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Application of Ozonation, UV Photolysis, Fenton Treatment and other Related Processes for Degradation of Ibuprofen and Sulfamethoxazole in Different Aqueous Matrices
Abstract
Two pharmaceuticals ibuprofen (IBP) and sulfamethoxazole (SMX) were treated with ozone and advanced oxidation processes (AOPs): UV photolysis, O3/H2O2, O3/UV, O3/H2O2/UV, H2O2/UV, the Fenton and photo-Fenton process. The efficacy of AOPs for degradation of pharmaceuticals as well as the impact of the matrix (pure water, urea and wastewater) on drugs' decay was evaluated. The experimental study has been carried out using concentration of the pharmaceuticals in the level of 100 mg/L. IBP was more resistant to all types of treatment than SMX. Ozonation was effective for removal of SMX and IBP when carried out under alkaline conditions. The ultimate elimination of SMX could be achieved with UV photolysis, whereas more rapid removal of IBP was attained with H2O2/UV. The complete SMX removal and more than 90% IBP degradation by the ordinary Fenton treatment were reached with oxidant overdosing only. Additional UV-radiation improved substantially the performance of the Fenton oxidation for elimination of both pharmaceuticals. The elimination rates determined in the pure water cannot be directly used to predict the oxidation of SMX and IBP in the wastewater.
... Advanced oxidation processes (AOPs) constitute nowadays an environmental sound technology characterized by the production of reactive oxygen species like hydroxyl radicals ( • OH), which are one of the most reactive species known in the environment, with second-order rate constants for most organic compounds of 10 8 -10 10 M −1 s −1 (Buxton et al. 1988;Zepp et al. 1987). The degradation of SMX was widely evaluated using different AOPs, such as ozonation (Gonçalves et al. 2012), Fe 2+ /H 2 O 2 (Fenton) (Boreen et al. 2004;Epold et al. 2012), O 3 /UVC (Epold et al. 2012), H 2 O 2 /UVC (Epold et al. 2012;Richard et al. 2014), H 2 O 2 /O 3 /UVC (Epold et al. 2012), anodic oxidation (Dirany et al. 2010), TiO 2 /UVA (Nasuhoglu et al. 2011), classical photo-Fenton (Fe 2+ /H 2 O 2 / UVA) (Epold et al. 2012;Trovó et al. 2009), and modified photo-Fenton with Fe 3+ using complexing agents (Dias et al. 2014). As far as we know, no studies on AMI degradation by AOPs were done. ...
... Advanced oxidation processes (AOPs) constitute nowadays an environmental sound technology characterized by the production of reactive oxygen species like hydroxyl radicals ( • OH), which are one of the most reactive species known in the environment, with second-order rate constants for most organic compounds of 10 8 -10 10 M −1 s −1 (Buxton et al. 1988;Zepp et al. 1987). The degradation of SMX was widely evaluated using different AOPs, such as ozonation (Gonçalves et al. 2012), Fe 2+ /H 2 O 2 (Fenton) (Boreen et al. 2004;Epold et al. 2012), O 3 /UVC (Epold et al. 2012), H 2 O 2 /UVC (Epold et al. 2012;Richard et al. 2014), H 2 O 2 /O 3 /UVC (Epold et al. 2012), anodic oxidation (Dirany et al. 2010), TiO 2 /UVA (Nasuhoglu et al. 2011), classical photo-Fenton (Fe 2+ /H 2 O 2 / UVA) (Epold et al. 2012;Trovó et al. 2009), and modified photo-Fenton with Fe 3+ using complexing agents (Dias et al. 2014). As far as we know, no studies on AMI degradation by AOPs were done. ...
... Advanced oxidation processes (AOPs) constitute nowadays an environmental sound technology characterized by the production of reactive oxygen species like hydroxyl radicals ( • OH), which are one of the most reactive species known in the environment, with second-order rate constants for most organic compounds of 10 8 -10 10 M −1 s −1 (Buxton et al. 1988;Zepp et al. 1987). The degradation of SMX was widely evaluated using different AOPs, such as ozonation (Gonçalves et al. 2012), Fe 2+ /H 2 O 2 (Fenton) (Boreen et al. 2004;Epold et al. 2012), O 3 /UVC (Epold et al. 2012), H 2 O 2 /UVC (Epold et al. 2012;Richard et al. 2014), H 2 O 2 /O 3 /UVC (Epold et al. 2012), anodic oxidation (Dirany et al. 2010), TiO 2 /UVA (Nasuhoglu et al. 2011), classical photo-Fenton (Fe 2+ /H 2 O 2 / UVA) (Epold et al. 2012;Trovó et al. 2009), and modified photo-Fenton with Fe 3+ using complexing agents (Dias et al. 2014). As far as we know, no studies on AMI degradation by AOPs were done. ...
The present study aims to assess the removal of 3-amino-5-methylisoxazole (AMI), a recalcitrant by-product resulting from the biological breakdown of some pharmaceuticals, applying a solar photo-Fenton process assisted by ferrioxalate complexes (SPFF) (Fe3+/H2O2/oxalic acid/UVA-Vis) and classical solar photo-Fenton process (SPF) (Fe2+/H2O2/UVA-Vis). The oxidation ability of SPFF was evaluated at different iron/oxalate molar ratios (1:3, 1:6, and 1:9, with [total iron] = 3.58 × 10−2 mM and [oxalic acid] = 1.07 × 10−1, 2.14 × 10−1 and 3.22 × 10−1 mM, respectively) and pH values (3.5–6.5), using low iron contents (2.0 mg Fe3+ L−1). Additionally, the use of other organic ligands such as citrate and ethylenediamine-N,N′-disuccinic acid (EDDS) was tested. The oxidation power of the classical SPF was assessed at different pH values (2.8–4.0) using 2.0 mg Fe2+ per liter. Furthermore, the effect of AMI concentration (2–20 mg L−1), presence of inorganic ions (Cl−, SO42−, NO3−, HCO3−, NH4+), and radical scavengers (sodium azide and D-mannitol) on the SPF method at pH 3.5 was also assessed. Experiments were done using a lab-scale photoreactor with a compound parabolic collector (CPC) under simulated solar radiation. A pilot-scale assay was conducted using the best operation conditions. While at near neutral pH, an iron/oxalate molar ratio of 1:9 led to the removal of 72 % of AMI after 90 min of SPFF, at pH 3.5, an iron/oxalate molar ratio of 1:3 was enough to achieve complete AMI degradation (below the detection limit) after 30 min of reaction. The SPF process at pH 3.5 underwent a slower AMI degradation, reaching total AMI degradation after 40 min of reaction. The scale up of SPF process showed a good reproducibility. Oxalic and oxamic acids were identified as the main low-molecular-weight carboxylic acids detected during the pilot-scale SPF reaction.
Graphical abstract
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... Among the combined processes, H 2 O 2 /O 3 is a well-known and powerful method denominated as peroxone, which involves direct and indirect oxidation of pollutants. The effectiveness of H 2 O 2 /O 3 has been proven towards the degradation of 1,4-dioxane [6,13], dyes [14], pharmaceuticals [15,16], volatile organic compounds (VOCs) [17] and wastewaters [18,19]. In peroxone process, HO ...
... The parameter E EO (kWh m − 3 order − 1 ) describes the amount of energy required to degrade 90 % of pollutant in 1 m 3 of the contaminated liquid. The calculations were conducted considering the power of HC system and O 3 generator, which were 0. 16 In general, the ranges of E EO values determined for ozonation, peroxone and UV-based AOPs are 0.041-0.73, 0.86-5.96 ...
Hydrodynamic cavitation (HC) was employed to activate sodium percarbonate (SPC) and ozone (O3) to degrade recalcitrant 1,4-dioxane. The degradation efficiency > 99 % with a rate constant of 4.04 × 10−2 min−1 was achieved in 120 min under the optimal conditions of cavitation number (Cv) 0.27, pH 5, molar ratio of oxidant to pollutant (rox) 8, ozone dose of 0.86 g h−1 under 25 ± 2 °C with initial concentration of 1,4-dioxane 100 ppm. The application of HC with SPC/O3 increased the degradation efficiency by 43.32 % in 120 min, confirming a synergistic effect between the coupled processes. In addition, the degradation efficiency of 1,4-dioxane in HC/SPC/O3 was superior as compared to HC/H2O2/O3, suggesting that the presence of SPC has a significant role in degradation of 1,4-dioxane. Radical quenching experiment revealed highest contribution of hydroxyl (HOradical dot) radicals in the degradation of 1,4-dioxane among carbonate (CO3radical dot−) and superoxide (O2radical dot−) radicals. The presence of co-existing anions resulted in an inhibitory effect in the following order: SO42− > NO3− > Cl−. Based on GC–MS analysis, ethylene glycol diformate (EGDF) was detected as the main degradation product of 1,4-dioxane. The observed intermediate supports the radical route of 1,4-dioxane oxidation, which involves H-abstraction, ΔC-C splitting at the α-C position, subsequent dimerization, fragmentation and mineralization. Electric energy per order (EEO) for best process was 102.65 kWh·m−3·order−1. Total cost of treatment was estimated as approx. 12 USD/m3. These findings confirmed the SPC as an efficient, environmentally-friendly alternative to H2O2 and broadened the scope of HC-based AOPs for water and wastewater treatment.
... They are known as advanced oxidation processes, and they use oxidants (such as the aforementioned hydroxyl radical) that are responsible for decreasing the levels of chemical oxygen demand (COD)/biological oxygen demand (BOD) by separating the oxidizable organic and inorganic components. AOP is considered an alternative to traditional methods and that makes it possible to increase the degradability of contaminants in waste water and the inactivation of pathogenic organisms [39,40]. ...
... However, problems arise in ozonization processes due to the limitations of UV irradiation [69]. where most of the removal of SMX was achieved with UV photolysis, and the most rapid removal of IBP was achieved with H2O2/UV [39]. Likewise, Rodríguez-Chueca et al. (2019) performed wastewater treatments using different types of AOPs for the removal of more than 53 antibiotics, among which are macrolides (azithromycin: through 100%), fluoroquinolones (ciprofloxacin and ofloxacin: through 100%), sulfonamides (sulfadiazine 95% sulfamethoxazole 50%), lincosamides, and nitromidazole (metronidazole 90%), among others, and these removal methods via AOPs were successful as evidenced by good removal [70]. ...
In recent decades the presence of pollutants has grown considerably around the world, along with the scarcity of fresh water. One of the environmental problems that has intensified lately is the presence of antibiotic resistant strains and the appearance of resistant genes due to the misuse and high worldwide consumption of this type of pharmaceutical products. Therefore, the number of investigations has been intensified to address these great problems that can affect public health and cause great economic losses around the world. For this reason, in this review, different antibiotics removal techniques in water have been compiled and analyzed critically.
... The traditional treatment systems, such as coagulation, sedimentation, and biological process, suffer from numerous disadvantages when they are used for the degradation of micropollutants. Hence, advanced oxidation processes (AOPs) based on free radicals (HO* and SO 4 -*) have been developed with a high degree of urgency for effective treatment of residual antibiotics in the environment [10][11][12]. There are many methods to generate free radicals from persulfate (PS) for the degradation of antibiotics, for example, those involving heat activation [13][14][15], transition metal ions [16][17][18], ultrasonics [19], bases [20], UV light [13,21,22], and activated carbon [23,24]. ...
... Al 3+ + 3OH-→Al(OH) 3 (10) 2Al(OH) 3 ...
The removal mechanisms of ciprofloxacin (CIP) in an aqueous solution using the persulfate (PS) oxidation system activated by zero-valent metals (ZVMs), such as zero-valent iron (ZVI), zero-valent aluminum (ZVA), and zero-valent copper (ZVC), were compared. The CIP removal followed the pseudo-first-order kinetics in all the PS oxidation processes mediated by the ZVMs. The influence of factors of the PS oxidation system, such as pH, and concentrations of both ZVMs and PS, was analyzed. Our results indicate that ZVI/PS process resulted in the highest removal of CIP at 84.5 ± 1.3 % (k obs = 29.8 × 10 −3 min-1) within 60 min with pH o of 3.0, a molar dosage of PS at 2.25 mM and concentration of ZVI at 126 mg L-1. However, CIP was only removed to the extent of 73.3 ± 2.5 % with k obs = 21.9 × 10 −3 min-1 by ZVA/PS with pH o of 3.0, [PS] o = 2.25 mM and concentration of ZVA at 81 mg L-1. Finally, for ZVC/PS system, the removal efficiency of CIP was lowest at 59.9 ± 3.2 % with constant rate k obs = 15 × 10 −3 min-1 when optimum conditions were initial pH of 4.0, [PS] o = 2.25 mM and dosage of ZVC at 192 mg L-1. Based on X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) spectra, Fe 2+, and Fe 3+ ions from ZVI, Al 3+ ions from ZVA, and Cu + and Cu 2+ ions from ZVC were released by PS oxidation. Moreover, active radicals (HO*, SO 4 *-) determined as primary agents to total oxidation performance, were generated through the activation of PS by intermediate ion metals.
... In the AOPs, hydroxyl radicals are the primary oxidants that attack and decompose organic compounds (their characteristics and effectiveness are described elsewhere [23]). Among various AOPs, UV photolysis, ozonation, and their combination are potential technologies capable of destroying organic pollutants in water and wastewater [21,[24][25][26][27]. ...
... Ozone (O 3 ) has been successfully employed for the disinfection and decomposition of dissolved organic pollutants [21,[24][25][26][27]. Several studies have shown that ozonation could effectively remove certain PPCPs [9,14,17,21,[28][29][30]. ...
A municipal wastewater treatment plant (WWTP) is a melting pot of numerous pharmaceuticals and personal care products (PPCPs) together with many other substances. The removal of PPCPs using advanced oxidation processes within a WWTP is one way to reduce the amount of PPCPs that potentially enter an aquatic environment. The aim of this study was to examine the effectiveness of the ozone (O 3)/UV treatment process, especially, the effects of O 3 dose and reaction time, on the removal of PPCPs in the secondary effluent of a WWTP. Experiments were conducted using a pilot-scale treatment process that consisted of two flow-through reactors connected in series. Each reactor was equipped with three 65 W lamps (UV 65W). The experimental variables were ozone dosage (1, 2, 3, 4, and 6 mg L −1) and hydraulic retention time (HRT; 5 and 10 min). On the basis of the PPCP concentrations after O 3 /UV 65W treatment and their limit of detection (LOD), 38 PPCPs detected in the secondary effluent were classified into 5 groups ranging from the category of "sensitive" to O 3 /UV 65W or "unstable" in the O 3 /UV 65W process to the category of "insensitive" to O 3 /UV 65W or "very stable" in the O 3 /UV 65W process.
... Advanced oxidation processes (AOPs) are one of the most effective methods to remove bio-recalcitrant organic compounds [6][7][8]. Previous efforts have applied the following AOPs for SA treatment: O 3 -based AOPs (i.e., O 3 /H 2 O 2 , O 3 /UV, and O 3 /H 2 O 2 /UV) [9,10]; Fenton-and photo-Fenton-based AOPs (i.e., Fe 2+ /H 2 O 2 and Fe 2+ /UV/H 2 O 2 ) [10,11]; and, persulfate (PS)-or peroxymonosulfate (PMS)-based AOPs activated with UV light [11,12], heat [13][14][15], or transition metals [16,17]. Traditional AOPs, including Fe 2+ /H 2 O 2 , O 3 /H 2 O 2 , and UV/ H 2 O 2 , produce highly oxidative hydroxyl radicals ( % OH); however, PS and PMS oxidation techniques generate sulfate radicals (SO 4 %− ), which are considered more effective than % OH for some scenarios [18]. ...
... Advanced oxidation processes (AOPs) are one of the most effective methods to remove bio-recalcitrant organic compounds [6][7][8]. Previous efforts have applied the following AOPs for SA treatment: O 3 -based AOPs (i.e., O 3 /H 2 O 2 , O 3 /UV, and O 3 /H 2 O 2 /UV) [9,10]; Fenton-and photo-Fenton-based AOPs (i.e., Fe 2+ /H 2 O 2 and Fe 2+ /UV/H 2 O 2 ) [10,11]; and, persulfate (PS)-or peroxymonosulfate (PMS)-based AOPs activated with UV light [11,12], heat [13][14][15], or transition metals [16,17]. Traditional AOPs, including Fe 2+ /H 2 O 2 , O 3 /H 2 O 2 , and UV/ H 2 O 2 , produce highly oxidative hydroxyl radicals ( % OH); however, PS and PMS oxidation techniques generate sulfate radicals (SO 4 %− ), which are considered more effective than % OH for some scenarios [18]. ...
Sulfamethazine (SMZ) is one of the most widely used sulfonamides and is frequently detected in water resources, posing threats to human and ecological health. To address this concern, SMZ degradation was investigated using nanoscale zero-valent iron (nZVI) supported on an organo-montmorillonite (OMt) composite (nZVI/OMt), which was synthesized by reduction of Fe²⁺ with NaBH4, to activate persulfate (PS). Up to 97% degradation of 20 mg/L SMZ was achieved within 10 min using 1.5 mM nZVI/OMt (mass/mass, 3/1) and 4 mM persulfate at pH 6.8 and 25 °C. Experimental results indicated that SMZ degradation obeyed pseudo-first-order reaction kinetics, and the observed pseudo-first-order rate constant (kobs) in the nZVI/OMt-activated PS process was 1.5 times that for the nZVI-activated PS process. SMZ transformation was improved by increasing the PS concentration and temperature. Natural water constituents, such as Cl⁻, NO3⁻, and humic acid, slightly inhibited SMZ degradation, whereas SMZ transformation was significantly reduced by HCO3⁻. Electron paramagnetic resonance and radical scavenger experiments demonstrated that both [rad]OH and SO4[rad]− participated in SMZ degradation; however, SO4[rad]− was the dominant reaction mechanism. Degradation products were analyzed by UPLC-QTOF-MS and confirmed three reaction pathways: cleavage of the S–N bond; smiles-type rearrangement; and, oxidation of the aniline moiety. Overall, the experimental results suggest that nZVI/OMt-activated PS oxidation is an easy, low-cost, and efficient method for rapid remediation of SMZ-contaminated water.
... Other laboratory studies indicated that IBU was susceptible to photodegradation where degradation rates varied from 90% (Epold et al., 2012) to 60% (Giri et al., 2010). More recent studies have confirmed the photolysis of IBU and have reported on the identification of degradation products where (Jakimska et al., 2014) (Jakimska et al., 2014) identified five transformation products whereas Li et al., 2015(Li et al., 2015 reported the presence of degradation products, without identifying them, and reported that they had higher toxicity levels compared to the parent compound. ...
... To date, and to the authors' best knowledge, the synergetic effects of photolysis and thermal effects on the degradation of pharmaceuticals, and in particular IBU, have not been undertaken. Most studies that used artificial lamps supplied their reactor with a cooling setup to maintain temperature below 25°C (Epold et al., 2012;Giri et al., 2010;Li et al., 2015). In addition, other studies, which focused on the effect of natural sunlight, studied IBU degradation in surface water under environmental temperature variations (Tixier et al., 2003), or used transparent reactor vessels which maintained a constant room temperature (Yamamoto et al., 2009). ...
The increase in demand for, and disposal of, pharmaceuticals, positively correlated with the growing human population, has led to the emergence of contaminants with high environmental and health impacts. Several developing countries that endure problems related to water sufficiency and/or quality resort to the use solar stills as an affordable water treatment method. This research is aimed at investigating the fate of five chemically distinct pharmaceuticals that might pervade solar stills; ibuprofen (IBU), diclofenac (DCF), carbamazepine (CBZ), ampicillin (AMP) and naproxen (NPX). The experiments were conducted under three conditions. The first condition studied the combined effect of temperature and light in simulated field-test-scale solar stills. The effect of temperature as a sole variable was investigated in the second while the third condition studied the effect of light only via concentrated solar power (CSP). Results show that distillates from solar stills did not contain the parent compounds for four out of the five pharmaceuticals. IBU was the only pharmaceutical that showed a transfer via vapor into the distillate with the highest recorded transfer percentage of 2.1% at 50 °C when subjected to temperature alone and 0.6% under the combined effect of temperature and light. In the case of NPX and DCF, the parent compounds did not undergo transfer into the distillate phase; however their degradation by-products did. In addition, the results also showed that in the case of NPX, IBU and CBZ both high temperatures and sunlight combined were required to attain noticeable degradation. CSP accelerated the degradation of DCF, NPX and IBU with a three-minutes-degradation percentage of 44%, 13% and 2% respectively.
... Typically, additional measures are necessary for the treatment of solid wastes and renewal of the adsorbent, resulting in an increased financial burden on the whole process. Various chemical processes, including are frequently employed for the purpose of removing synthetic dyes (Epold et al., 2012, Arslan et al., 2000. Nevertheless, the production of toxic and unstable metabolites during these processes has detrimental impacts on the health of both animals and humans. ...
Excessive exposure of human to organic contaminants from industrial effluents calls for the implementation of effective pollutants removal techniques. This article investigates the photocatalytic degradation of bromophenol blue dye using Strontium oxide nanoparticles co-doped with Nickel and Zinc. Hydrothermal synthesis produced the nanoparticles, which were subsequently characterized using various analytical techniques. UV/Visible revealed absorption peaks at 294 nm, 306 nm, 311 nm, and 318 nm, while FTIR spectroscopy identified stretching peaks at 416 cm-1, 588 cm-1, and 856 cm-1 for Ni-O and Sr-O bonds. The nanoparticles displayed diameters ranging from 30.50 nm to 36.97 nm. EDX analysis confirmed the elemental composition, with Sr and O comprising of approximately 82.02 %, and Ni and Zn approximately 3.21%. Photocatalytic degradation experiments demonstrated that SrO nanoparticles 85.42% degradation efficiency, while co-doped SrO nanoparticles achieved an impressive 97.97% degradation efficiency. This work highlights the potential co-doped SrO nanoparticles as a promising solution for the efficient removal of organic pollutants from the industrial wastewater, addressing environment contamination concerns.
... The effective approach to deal with pharmaceutical residues is to prevent them from getting into water sources and streams by improving wastewater treatment (Behera et al., 2011;Epold et al., 2012). Conventional wastewater treatment methods incorporate physical, chemical, and biological processes. ...
Considering the health effects of antibiotics in the environment, effective monitoring and treatment technologies are needed to mitigate social and environmental impacts. The present study was carried out to investigate the efficiency of the constructed wetland (CW) on the removal of Ciprofloxacin (CIP) from aqueous samples. Experiments were conducted in pilot scale CWs planted with single plants of Cyperus alternifolius, Canna indica and one planted with both plant species. Analysis of CIP concentrations in the influent and effluent samples was done using Cary 60 UV–Vis spectrophotometer, while physical-chemical parameters were monitored for the influent and effluent samples. The removal efficiency of physico-chemical parameters was ˃70% for Nitrate, ˃60% for Phosphate, ˃70% for BOD and ˃77% for COD. The maximum removal of CIP (77.1%) was observed in CW planted with Cyperus alternifolius during a 7 days hydraulic retention time (HRT). The results of this study show superior performance of Cyperus alternifolius than Canna indica. There was no significance difference (p > 0.05) produced by mixing the two plants in a CW. However, mixing of plants especially ornamental plants in CWs brings good visual impression of the systems while treating the wastewater. This study demonstrate that CW can remove antibiotics from wastewater. The best performance depends on best selection and best combination of the plants.
... Adsorption, UV, oxidation, ozonation, photocatalytic degradation, Fenton's Reagent, and biodegradation are only a few of the methods that have been used to date to remove SMX from water [20][21][22][23]. Adsorption has been identified as an efficient, low-cost water treatment technology because it is simple to operate and produces no or very few harmful byproducts [24][25][26][27][28][29][30]. Adsorbents with desired qualities such as hydrophobicity, porous texture, and surface charge, are frequently regarded as the most useful materials for SMX removal [31][32][33]. ...
Antibiotic resistance genes represent treatment challenges for wastewater treatment systems. These resistance genes are a direct outcome of insufficient treatment of antimicrobial substances within wastewater treatment plants. Thus, this research work concentrated on a typical antibiotic sulfamethoxazole (4-amino-N-[5-methyl-3-isoxazolyl]-benzene sulfonamide or SMX). In this study, the effectiveness of SMX adsorption onto ordered mesoporous carbon (OMC) was first systematically evaluated. SEM, TEM, and BET were used to examine the morphology of OMCs, while XPS, FTIR, and Boehm titration were used to determine the functional groups present on OMCs. The specific surface was found to be 1395.31m²/g for OMC-900. The behavior of adsorbing SMX onto OMCs was evaluated using kinetics and isotherms studies. The influence of solution pH, temperature, coexisting ions, and natural organic matter (NOM) were also evaluated as to their impacts on SMX adsorption. The results revealed that the mesopores in OMC contributed significantly to SMX adsorption capacity. Adsorption achieved equilibrium after 4 hours with an adsorption capacity of 334 mg/g. The Pseudo Second Order Kinetic Model provided a good fit for the adsorption kinetic processes of SMX. The Freundlich Isotherm Model, which suggests physical adsorption, provides a better fit for adsorption isotherm data. The adsorption of SMX onto OMC was exothermic and spontaneous, according to thermodynamic analyses. Most importantly, the adsorption mechanisms of SMX onto OMC include hydrogen bonding and electrostatic interaction. Additionally, a key adsorption mechanism was found to be the affinity (π- π interactions) between the aromatic structures of OMC and the benzene ring in SMX molecule. This study reports a thorough understanding of adsorption components and mechanisms involved in the adsorption of SMX onto OMCs and also the regeneration of OMCs after adsorption.
... In addition, organic compounds can be oxidized and become degradable by ozonation [10]. Ozone has been successfully used for the disinfection and decomposition of dissolved organic pollutants [11][12][13][14][15][16]. Ozone is a strong oxidant that reacts as molecular ozone or through the formation of secondary oxidants, such as free radicals [17]. ...
The objective of this study is to investigate the consequence of ozone dosage rate on the qualitative change in organic compounds and nitrogen in anaerobic digester effluent during the ozone process. Therefore, ozonation improves the biodegradability of recalcitrant organic compounds, quickly oxidizes the unsaturated bond, and forms radicals that continue to deteriorate other organic matter. In this study, ozonation was performed in a microbubble column reactor; the use of microbubble ozone improves the status of chemical oxygen demand (COD) and changes of organic nitrogen to inorganic compounds. The ozone injection rates were 1.0, 3.2, and 6.2 mg/L/min. The samples obtained during the ozone treatments were monitored for CODMn, CODCr, TOC, NO2−-N, NO3−-N, NH4+-N, T-N, and Org-N. The ozone dose increased 1.0 to 6.2 mg/L and it increased the degradation ratio 40% and the total organic carbon 20% during 20 min of reaction time. During the ozonation, the CODCr and CODMn values were increased per unit of ozone consumption. The ozone treatment showed organic nitrogen mineralization and degradation of organic compounds with the contribution of the microbubble ozone oxidation process and is a good option for removing non-biodegradable organic compounds. The original application of the microbubble ozone process, with the degradation of organic compounds from a domestic wastewater treatment plant, was investigated.
... Reaction runs in three-neck round-bottom flasks equipped with an ozone inlet, an ozone outlet, and a sampling port (Epold et al., 2012). Ozone is supplied from the ozone generator IONTECH QLA-3G with a constant ozone flow rate of 100 mL/min for 2 h under continuous stirring and a constant temperature of 30°C. ...
This paper presents a novel approach to remove ciprofloxacin from an aqueous solution using Fe3O4/C material by adsorption and then followed by a degradation process using several advanced oxidation technologies, i.e., heterogeneous Fenton and catalytic ozonation. Porous carbon material was synthesized through several stages, i.e., polymerization of resorcinol-formaldehyde and carbonization (800 °C). The properties of porous carbon (blank carbon and Fe/C) were characterized by N2-sorption analyzer, SEM-EDX, XRD, and TGA. The adsorption isotherm data were well described by the Langmuir isotherm model with ciprofloxacin uptake up to 208.31 mg g⁻¹ and 189.38 mg g⁻¹ at 30°C by Fe/C and blank carbon material, respectively. The maximum uptake was influenced by adsorption temperature and mesopore volume of material. After adsorbing the ciprofloxacin, the Fe/C material was contacted with H2O2 and ozone to produce hydroxyl radicals (OH*). The result showed that ciprofloxacin was degraded about 99.7% within 120 min at 30°C through heterogeneous Fenton oxidation. The degradation performance for the other two oxidation processes: catalytic ozonation and combined ozonation-Fenton (O3/H2O2), has been explored as well. The process using O3/H2O2 could degrade ciprofloxacin quickly. In addition, Fe/C material could be reused during cyclability test without significantly reducing the catalytic activity.
... ozone transfer from gas phase to liquid phase) have an effect on the efficiency of ozonation and/or O 3 /H 2 O 2 for TrOCs removal. For example, the degradation of ibuprofen, sulfamethoxazole and phenol is more efficient at alkaline pH compared to acidic pH [78][79][80]. Indeed, more than 98% of ibuprofen and sulfamethoxazole was degraded at a pH between 9 and 12. When ozonation takes place at alkaline pH, • OH generation is increased and as a result the treatment efficiency is also enhanced [81]. ...
Trace organic contaminants (TrOCs) have been increasingly found in the aquatic environment and their potential health risk on human and wildlife has attracted more attention. Ozone-based advanced oxidation processes (AOPs) are a key technology for the removal of TrOCs from water and wastewater. This review provides an overview of current research and technology development regarding the application of ozone-based AOPs for TrOCs abatement. Performance of ozonation as a stand-alone process, as well as combined processes, including O3/H2O2, O3/UV, O3/catalysts, O3/plasma and O3/filtration for the removal of TrOCs in various types of (waste)water is discussed. Furthermore, this review also analyses the main mechanisms of oxidation by-products generation and compares and discusses the energy consumption during the application of ozone-based AOPs.
... Advances in water and wastewater treatment have led to the development of promising technologies, involving highly reactive hydroxyl radicals (HO • ), termed as advanced oxidation processes (AOPs). Ozonation, Fenton and electro-Fenton treatment, electrochemical and photocatalytic oxidation have been studied for aqueous DCF [38][39][40][41], IBU [38,[42][43][44][45], TMD [46][47][48][49][50] and MTF [51][52][53][54][55][56][57] removal. ...
Aqueous pharmaceuticals present an emerging environmental problem for their potent character. Advanced oxidation processes (AOPs) present efficacious abatement strategy, being, however, unaffordable in mass application. Energy efficient gas-phase pulsed corona discharge was experimentally studied for oxidation of aqueous ibuprofen, diclofenac, metformin and tramadol showing the energy yields of 53, 21, 15 and 89 g kW-1 h-1, respectively, at 10 mg L-1 initial concentrations, surpassing other AOPs. Impacts of alkaline pH and starting concentrations on oxidation energy efficiency are beneficial to various extents to all considered pharmaceuticals. The removal efficiency was found to correlate with molecular structure and hydrophobicity of medications.
... As can be observed, a low removal of IBU at its ThOD value was reached and which was kept constant around 25% during the time on stream of the continuous CWPO reaction. This result is in accordance to the study accomplished by Epold et al. (2012aEpold et al. ( , 2012b, where it was found an IBU removal of 90% by Fenton treatment using an oxidant overdosing and pH of 5. Secondly, the evolution of the DCF alone removal by CWPO treatment at a feed stream pH value of 5 has been depicted. In this case, it could be observed a higher DCF efficiency removal than IBU, reaching to a constant value close to 90% during 180 min of continuous CWPO reaction. ...
This research has been focused on the removal of two anti-inflammatory drugs, diclofenac (DCF) and ibuprofen (IBU), by a continuous catalytic wet peroxide oxidation (CWPO) process using a lab-synthesized nanomagnetic catalyst (Fe3O4/MWCNTs). The central composite rotatable design (CCRD) method was used to study the effect of DCF and IBU concentration (expressed as theoretical oxygen demand (ThOD) between 0 and 52.5 mg L⁻¹) and of the feed stream pH (from 3 to 7) on the removal of total organic carbon (TOC) and the concentration of aromatic compounds (Arm) and total phenolic compounds (TP) by CWPO. It could be observed that DCF was preferably removed from the DCF-IBU aqueous mixture at pH values ranging from 3 to 5. In addition, feed stream pH had a significant effect on the pollutants removal, as well as on TOC, TP and aromatic compounds removal, observing an increasing in the pollutants degradation when feed stream pH decreased from 7 to 3. Quadratic models predicted for response variable, such as TOC, TP and aromatic compounds removal, and their maximum model-predicted removal values were of 90.0, 80.2 and 90.0%, respectively. Finally, as a proof of concept, three environmentally-relevant aqueous matrices, spiked with DCF-IBU mixture, were treated. In this case, relatively high TOC degradation values were found after 20 h reaction time (ca. 57.7, 73.9 and 54.5% in surface water, WWTP effluent and hospital wastewater, respectively). This work deals the first study about DCF-IBU removal in aqueous solution by CWPO, as well as a continuous study using real wastewater that allow to extend the experimental results to a real scenario.
... To date, a variety of techniques have been applied to treat SMX in water, including adsorption, photocatalytic degradation, Fenton oxidation, ozonation, UV, and biodegradation (Epold et al., 2012;Gonçalves et al., 2013;Jang et al., 2018b;Kim and Kan, 2016;Yang et al., 2011). Adsorption, among these techniques, has been identified as a costeffective, easily operated, and scalable method to eliminate SMX from water (Jang et al., 2018b). ...
This work focused on the impacts of FeCl3 impregnation ratio on the properties of FeCl3-activated bermudagrass (BG)-derived biochars (IA-BCs), adsorption of sulfamethoxazole (SMX) onto IA-BCs and regeneration of SMX-spent IA-BC. Compared with the control BC (85.82 m²/g), IA-BCs made via pyrolysis with FeCl3 to BG mass ratio between 1 and 3 (1–3 g FeCl3/g BG) resulted in significantly enhancing surface area (1014–1035 m²/g), hydrophobicity, Fe content in IA-BCs (3.87–7.27%), and graphitized carbon. The properties of IA-BCs supported magnetic separation and higher adsorption (32–265 mg SMX/g BC) than the control BC (6–14 mg SMX/g BC) at various pH. Adsorption experiments indicated various adsorption mechanisms between SMX and IA-BCs via π-π EDA, hydrophobic interactions, and hydrogen bond with intraparticle diffusion limitation. The adsorption was also found to be spontaneous and exothermic. The IA-BC made at FeCl3 to BG mass ratio of 2 (IA-BC2.0) showed the maximum adsorption capacity for SMX (253 mg SMX/g BC) calculated from Langmuir isotherm model. Additionally, both NaOH desorption and thermal oxidation showed effective regeneration of SMX-saturated IA-BC2.0 over multiple cycles. After three cycles of adsorption-regeneration, 64% and 62% of regeneration efficiencies were still achieved under thermal treatment at 300 °C and desorption with 0.1 M NaOH solution, respectively, indicating a cost-efficient adsorbent for the elimination of SMX in water.
... Advanced oxidation processes (AOPs) have shown greater potential for the degradation and mineralization of recalcitrant and toxic organic pollutants, such as pharmcautical compounds, in water matrices than conventional treatment processes (Epold et al., 2012;Espejo et al., 2014;Klauson et al., 2019;Rosal et al., 2008;Wang and Zhuan, 2020). AOPs mainly include the use of different systems and/or combination of systems based on ozone (O 3 ), hydrogen peroxide (H 2 O 2 ), and persulfate (PS). ...
This study investigates the individual and simultaneous degradation and mineralization of the antibiotics, sulfamethoxazole (SMX) and trimethoprim (TMP) in aqueous solution by ozonation, ozone-activated persulfate (PS) and hydrogen peroxide (H2O2) processes. The trials were carried out in a semi-continuous column bubble reactor with an ozone diffuser located at the bottom of the column for a period of 2 hours. Furthermore, the efficiency of studied processes were evaluated at two different initial pH and various doses of oxidants. The target compounds degradation observed pseudo-first-order rate constants (kobs) and removal of total organic carbon (TOC) using ozone-based oxidation processes were compared. Irrespective of the applied processes, the mineralization of target compounds was less effective than their degradation in both individual and simultaneous systems. The highest antibiotics degradation rate constants were observed for individual oxidation of TMP (kobs=0.379 min⁻¹) and SMX (kobs=0.367 min⁻¹) at alkaline initial pH (pH0) in the O3/H2O2 system at an [antibiotic]/H2O2 molar ratio of 1/1. Irrespective of the antibiotic studied, the most effective TOC removal (∼44%) was observed after a 2-h treatment with the O3/H2O2 system at an [antibiotic]/H2O2 molar ratio of 1/5 (pH0 10.9). The O3/PS system at an [antibiotic]/PS molar ratio of 1/5 (pH0 10.9) proved the most effective system for both mineralization and degradation (kobs values of 0.294 min⁻¹ and 0.266 min⁻¹) of TMP and SMX, respectively, during the simultaneous oxidation of SMX-TMP. The decomposition by-products of SMX and TMP in studied ozone-based processes were identified using LC-MS analysis. The results of this study strongly suggest that using the O3/PS process is a promising solution to reduce SMX-TMP contamination in water matrices.
... AOP comprise photochemical (e.g. heterogenous photocatalysis, UV/H 2 O 2 and photo-Fenton), electrochemical, ozone-based and sonochemical processes (Długosz et al., 2015;Epold et al., 2012;Miklos et al., 2018). Sonochemical process is an interesting option because destruction of water contaminants can occur by thermal decomposition or radical reactions, also in some cases the process exhibits low interference from water matrix and it can be easily combined with other AOP (Miklos et al., 2018). ...
This work presents the degradation of ampicillin (a highly consumed β-lactam antibiotic) in aqueous media by sonochemical advanced oxidation processes. Initially, effects of frequency, power and operation mode (continuous vs. pulsed) on the antibiotic degradation by sonochemistry were analyzed. Then, under the suitable operational conditions, pollutant degradation and antimicrobial activity (AA) evolution were monitored. Afterwards, computational calculations were done to establish the possible attacks by the hydroxyl radical to the ampicillin structure. Additionally, the antibiotic degradation in synthetic hydrolyzed urine by ultrasound was performed. Finally, the combination of sonochemistry with Fenton (sono-Fenton) and photo-Fenton (sono-photo-Fenton) was evaluated. Our research showed that ampicillin removal was favored at low frequency, high power (i.e., 375 kHz, 24.4 W) and continuous mode (exhibiting an initial degradation rate of 0.78 μM min⁻¹). Interestingly, ampicillin degradation in the hydrolyzed urine by sonochemistry alone was favored by matrix components (i.e., the pollutant showed a degradation rate in urine higher than in distilled water). The sonochemical process decreased the antimicrobial activity from the treated water (100% removal after 75 min of treatment), which was related to attacks of hydroxyl radical on active nucleus (the computational analysis showed high electron density on sulfur, oxygen and carbon atoms belonging to the penicillin core). Sono-photo-Fenton system achieved the fastest degradation and highest mineralization of the pollutant (40% of organic carbon removal at 180 min of treatment). All these aspects reveal the good possibility of sonochemical advanced oxidation technologies application for the treatment of antibiotics even in complex aqueous matrices such as hydrolyzed urine.
... Indeed, there is a possibility that micropollutants, present in small amounts, may not get enough oxidants. However, at least some advanced oxidation processes (AOPs) have already shown selective performance in the degradation of micropollutants in simulated or real wastewater samples [26][27][28][29][30]. ...
In this work, four advanced oxidation processes, namely heterogeneous photocatalysis, ozonation, homogeneous and heterogeneous Fenton-like treatment, were studied separately and in combinations and compared for the degradation of a widely used sulfonamide group antibiotic, sulfamethizole. The trials were carried out in a column bubble reactor operated in semi-batch and continuous mode. The applicability of the selected processes for sulfamethizole degradation was investigated at elevated concentrations (ppm level), with subsequent successful scale-down to ppb concentration level. Among studied methods, the application of ozone-based processes demonstrated the highest sulfamethizole decomposition efficiency, with 25 µg L-1 of antibiotic being completely degraded in three minutes, even though low ozone amounts (99 µg O3 min-1) were used, comparable to those produced by germicidal lamps. The highest target compound decomposition efficiency was shown by uncoated expanded clay-assisted ozonation, where complete sulfamethizole removal was obtained within one minute. The results show that operating at elevated concentrations to determine the performance of a micropollutant degradation method is not only acceptable but also completely justified, as the scale-down study results reflect those obtained at higher concentrations quite accurately.
... Various treatment methods including biodegradation [12], adsorption [13], ozonation [14] and advanced oxidation process (AOP) [15] have been reported for the removal of PPCPs from contaminated streams. Biodegradation is most preferred for the treatment of waste streams. ...
Ag2[email protected] core-shell structured microspheres were prepared through a very simple, novel and green in-situ method using dimethyl sulfoxide as both the solvent and sulfur S source at low temperature (140 °C). The photocatalytic performance of synthesized samples was tested for degradation of acetaminophen (ACT) under visible light irradiation. ACT removal efficiency was directly depended on the GO-level in composite and the maximum photocatalytic yield was achieved for the sample with GO concentration of 0.2 g/L. Formation of Ag2S in the nanocomposite was confirmed using XRD, XPS and UV–Vis DRS and photoluminescence (PL) measurement. XRD patterns pointed to the existence of a wurtzite structure for all samples and by silver loading, Ag2S peaks were visualized in the XRD patterns, with increased intensity by rising the Ag content in the solution precursor. EDS and XPS data indicated the presence of sulfur and silver in the form of Ag⁺ and S²⁻. A considerable red shift in absorption edge and reduce in PL emission peak intensity was observed over the introduction of Ag in the precursor solution due to the existence of Ag2S. The Ag2[email protected] composites indicated enhanced photocatalytic performance toward degradation of ACT under visible light compared to bare ZnO and [email protected] The underlying mechanism has been investigated based on the results of UV–Vis DRS, PL and reactive species scavenging experiments. The improved photocatalytic activity is mainly ascribed to better light harvesting and increased photogenerated electron-hole separation. Ag2S play an important role in the composite due to the synergistic effect of Ag2S and rGO, which not only improve the light harvesting but also reduce the charge recombination. The as-made catalyst indicated a great potential for recycling, suggesting the potentially large-scale applications of prepared catalyst for emerging water contaminants and wastewater treatment. The cytotoxicity of untreated and photocatalytic oxidation (PCO)-treated ACT solutions was evaluated using the cultured human embryonic kidney (HEK) cells, which revealed that ACT solution in the developed PCO system could be significantly detoxified.
... Moreover, the antibiotics are likely to pass without treatment from the conventional WWTPs that subsequently enter the drinking water system (Kümmerer, 2009;Wojcieszyńska et al., 2014). Elimination of such pharmaceuticals from the environment water and industrial effluents has been the focus of research for decades and thus to achieve the goal, efficient treatment technologies for degradation in aqueous matrices are required (Epold et al., 2012;Kattel et al., 2018;Owens and Dash, 2003). ...
The present study focuses on degradation and mineralization of a third generation cephalosporin antibiotic ceftriaxone (CTA) in UVA- and UVC-induced persulfate (PS) system combined with heterogeneous (α-FeO(OH) and Fe3O4) activators. The CTA oxidation efficiency was investigated in buffered solution (pH 7.4) to stimulate the inhibitory properties of environmental and processed water matrices. Irrespective of the studied UV-induced persulfate system, the mineralization was less effective than CTA degradation. In turn, UVC-induced systems proved to be more effective than UVA-induced processes for decomposition of the target compound and removal of TOC. Accordingly, 2-h oxidation in UVA-induced systems resulted in partial decomposition and negligible mineralization of CTA. While the application of UVC-activated persulfate processes resulted in complete CTA degradation during the first 15 min of oxidation with the most efficient kobs of 0.53 min−1 and 38.3% TOC removal obtained in the UVC/PS system at [PS]0 = 500 μM. Groundwater (GW) trials results clearly indicated the inhibitory effect of the GW composition on the effectiveness of CTA degradation in the studied UV-induced PS-based systems, while the potential treatment efficacy in GW proved predictable based on the results obtained in the buffered UW trials. Adjusting the pH to 3 considerably improved the removal of TOC and the use of PS in both of the water matrices studied. The results of radicals scavenging experiments indicated that both SO4− and HO contributed to the CTA decomposition efficacy in the UV-induced persulfate systems, but the former was the predominant radical in all studied processes. The findings of the study strongly suggest that the UV-induced PS systems are promising treatment technologies for the abatement of cephalosporin antibiotics pollution in natural aqueous matrices.
... Conventional water purification technologies such as chlorination in the disinfection of drinking water and biological degradation in wastewater treatment are not always effective in the treatment of influents contaminated by noxious and refractory organic micropollutants (Margot et al. 2015;Stackelberg et al. 2004). A promising solution to the issues discussed is the introduction of advanced oxidation technologies (AOTs), mainly based on the oxidative properties of hydroxyl radicals (HO•) and sulfate radicals (SO 4 • − ), into the technological scheme proposed for the purification of contaminated water (Babuponnusami and Muthukumar 2014;Epold et al. 2012;Matzek and Carter 2016;. ...
The efficacies of UV photolysis, UV-activated persulfate (UV/PS), and combined UV/Fe²⁺-activated persulfate (UV/PS/Fe²⁺) systems for degrading of different organic micropollutants in ultrapure water and groundwater were examined and compared. The studied micropollutants belonging to the different classes involved an artificial sweetener acesulfame K (ACE), beta-lactam antibiotic amoxicillin (AMX), and endocrine disrupting compound 4-nonylphenol (NP). Among the studied systems, the UV/PS/Fe²⁺ process showed the highest performance both in degradation and in mineralization of ACE (UVA-induced systems; kapp = 0.126 1/min and 80.3% TOC removal) and AMX (UVC-induced systems; kapp = 1.383 1/min and 85.4% TOC removal), followed by the UV/PS process. In the case of NP trials, the application of UVC/PS systems was the most promising, and after careful adjustment of oxidant concentration, it demonstrated a considerable improvement in the target compound degradation (at a NP/PS molar ratio of 1/4 kapp = 0.024 1/min) compared with the UVC photolysis (kapp = 0.016 1/min). Irrespective of the applied UV-induced treatment process, the efficacy of target compounds degradation was lower in groundwater as compared with ultrapure water trials.
... Organic materials typically contain toxic particles that affect benthic water clusters and alter the composition of fauna species (Cooper 1993). These organic materials contain a residue of pharmaceuticals used in veterinary (Dulova et al. 2011;Epold et al. 2012). Pollution not only severely deteriorates the condition of water ecosystems but also impedes the use of their water for different purposes and threatens human health (Burkholder et al. 2007). ...
The most dangerous pollution sources are intensive agricultural activity and livestock farming, whose production waste has a negative impact on soil and water quality. Livestock farming is separated into two systems: indoor (pigs and poultry) and pasture-based (livestock and sheep). Numerous studies aimed at elucidating how different systems affect the environment have been performed. In Lithuania, the biggest environmental problems are caused by 24 farms with more than 5000 pigs, 21 poultry farm with more than 1000 chickens, 2179 cow-cattle farms larger than 50 places, and about 200,000 sheep. We aimed to assess the quality of surface water in the Kaunas region next to the pig and livestock farms. In 2008–2017, seven livestock agricultural companies and seven larger farmers were regarded as potential sources of pollution in the Kaunas region. Half of these sources were pig farms, and the rest were livestock farms. Locations next to potential agricultural pollution sources were chosen to monitor the surface water. The results indicated that although the agricultural areas, number of livestock units, and nitrogen rate per 1 ha were similar between the pig and livestock farms, the activity on the pig farms affected the surface water quality more than that on livestock farms. As the number of livestock units (LU) increased on the farms, the pH decreased and the suspended materials, nitrates, and phosphates increased in the surface water. With increasing nitrogen kg/ha, the pH values decreased, thereby yielding more acidic water. The intensity of agricultural activity did not affect the water quality near the livestock farms, except for livestock units (LU), which affected the pH.
... Advanced oxidation processes (AOPs) have been studied extensively owing to their strong oxidizing power and high processing efficiency (Belkheiri et al., 2011;Epold et al., 2012;Liu et al., 2015). Among them, nonthermal plasma (NTP) based on glow discharge can effectively oxidize organics that are difficult to biodegrade by generating different radicals (Muhammad et al., 2001;Schiavon et al., 2017). ...
Biological treatment is insufficient for infield treatment of domestic wastewater that contains low amounts of carbon. This study proposes a pretreatment process for enhancing the nutrient removal efficiency by improving the biodegradability of organic matter using glow discharge nonthermal plasma (GDNTP), which generates several strongly oxidizing active species. A series of batch experiments was conducted at pH 5.0 and 9.0 to investigate removal of nitrogen based on either physiochemical effects or improvement of the biodegradability of organic matters by the GDNTP pretreatment. At pH 5.0, total nitrogen (TN) was not removed by chemical reactions with active species from the GDNTP generator, whereas more TN was removed by chemical reactions or air stripping with the gas discharged from GDNTP at pH 9.0. Part of nitrogen removal was not achieved by ammonia air stripping, but by the improvement of biodegradation due to the GDNTP pretreatment for each operational sequencing batch reactor cycle. Findings indicate that GDNTP pretreatment improves the denitrifying of nitrate rather than producing a better carbon/nitrogen (C/N) ratio.
... Ozone treatment is a promising technology to decompose organic pollutants (Epold et al. 2012;Huber et al. 2005;Klavarioti, Mantzavinos, and Kassinos 2009;Ternes et al. 2002;Zwiener and Frimmel 2000). Ozone is a strong oxidant with an oxidation potential of 2.07 V (Weast 1970). ...
This study investigated the degradability of pharmaceuticals and personal care products (PPCPs) by ozonation for the treatment of secondary effluent of a municipal wastewater treatment plant. A set of experiments were conducted in a laboratory using a pilot-scale process consisting of three flow-through reactors in series, by varying the ozone dose (1 to 9 mg L⁻¹), the hydraulic retention time (5 to 15 min), and the concentration of ozone injected into the reactors (14 – 42 mgL⁻¹). Thirty-seven PPCPs were detected in the secondary effluent, which belong to the use categories of antibiotics, analgesics, antiarrhythmic agents, anticonvulsants, vasodilators, lipid modifying agents, anti-itch drugs, anti-psychotic drugs, insect repellents, bronchodilators, diuretics, peptic ulcer drugs, NMDA receptor antagonists, antifungal drugs, antimicrobial drugs, and antineoplastic agents. These PPCPs were broadly classified into five groups ranging from “sensitive” to ozone (O3) or “unstable” in the ozonation process, to the group of “insensitive” to O3 or “very stable” in the ozonation process. These groups are based on the PPCP concentrations after the ozone treatment and their limit of detection (LOD). Further, this study examined comparatively the effects of the ozone dose, the retention (reaction) time, and the concentration of O3 supplied to the reactors on the degradability of the PPCPs.
... UV-photolysis thus may be an interesting option. For some types of contaminants commonly present in urban groundwater, photolysis by means of UV radiation may be an effective degradation method [4,5,8,10,13,22,23,27,31,32]. In addition to facilitating sustainable energy, ATES installation with a UV reactor might allow the remediation of contaminated groundwater. ...
In several places in The Netherlands, industrial areas are redeveloped into residential areas with sustainable heating systems based on aquifer thermal energy storages (ATES). At these sites, groundwater is contaminated with chlorinated ethenes. In this project various pilot set-ups were tested as a non-invasive technique to remove chlorinated ethenes from contaminated groundwater by integrating a UV reactor into the ATES system. It was demonstrated that per- and trichloro ethenes (PCE and TCE) can be photolyzed by LP UV-lamps up to 10–20% at a relatively high dose of 500 mJ/cm². However, the photolysis of cis-dichloro ethene (DCE) and vinyl chloride (VC) was limited to maximum 5%. In addition, it was found that, during the photolysis trans-DCE may be formed, which usually is not observed in biodegradation pathways of chloroethenes. As the groundwater composition at a certain location may show significant variations in time (concentration differences of a factor 2–3 were no exception during the various experiments) it is important to adjust the system to the range of concentrations that can be expected.
... The compounds which were degraded by means of O 3 at alkaline medium were phenol [11,12], dye [62], dibutyl sulfide (DBS) [10], perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) [69], dimethyl sulfoxide (DMSO) [15], Fluoxetine (FXT) [21,70], norfluoxetine (NFX) [70], Ranitidine [71], Ibuprofen (IBP) and Sulfamethoxazolein (SMX) [72]. Model dye, PFOS and PFOA were persistent to degradation as indicated in Table 1. ...
Advanced oxidation processes (AOPs) have been used as an alternative and effective option for treatment of industrial wastewater, especially in the case of the non-biodegradable compounds. Despite of several well developed AOPs, the majority of them are effective only at acidic or neutral pH, namely Fenton related processes, making the list of available effective advanced oxidation technologies strongly limited. In many cases, industrial effluents are formed at basic pH conditions. This paper reviews the state of the art of AOPs exclusively at alkaline pH, the type of compounds and effluents effectively degraded, the influence of pH on the efficiency of the processes, economic evaluation and degradation pathways. Spent caustic, polyester and acetate fiber dye effluents, phenol, acidic and sulfur based compounds, specific dyes and drugs were effectively degraded at basic pH. Factors like point of zero charge, pKa of the compounds, amount of radicals produced and activation of the oxidants are crucial factors that affect the treatment efficiency of AOPs at basic pH. H2O2 and O3 were the cheapest processes while peroxone was the most expensive. The treatment costs were in general too expensive and unrealistic using the methodology used in the literature. The alternative methodology proposed in this paper reduced the treatment costs by three orders of magnitude to values more realistic and economical feasible. Literature regarding treatment of real effluents using AOPs at basic pH is scarce and further research is needed to perform complete analysis. It is important to present some alternatives regarding the treatment of alkaline effluents without pH correction using such technologies.
... Therefore, these compounds are present in Sewage Treatment Plant (STP) effluents and are discharged into surface waters (Halling-Sørensen et al., 1998;Huber et al., 2003;Petrović et al., 2003Petrović et al., , 2005Radjenović et al., 2009;Rosal et al., 2010). Beside the classical biological treatments, Advanced Oxidation Processes (AOPs) like UV-photolysis and ozonation are promising for elimination of these emerging pollutants (Zwiener and Frimmel, 2000;Ternes et al., 2002Ternes et al., , 2003Huber et al., 2005;Klavarioti et al., 2009;Epold et al., 2012). ...
Development in industrial sectors such as textile, paints, paper, and cosmetics creates a complicated problem in the ecosystem and human health by utilizing binary coloring materials (methylene blue, rhodamine B, etc.). Photocatalysis is one such most widely used technology for environmental remediation, in which a sunlight-based initialing factor was utilized. However, issues related to conventional photocatalysis, like fast recombination of photo-generated electron and hole pairs, limited visible light absorption property, and poor redox abilities of the charge carriers, must be addressed to improve semiconductor photocatalysts properties and catalytic performance. Enormous efforts have been undertaken to overcome these problems. Modeling of semiconductor photocatalysts is beneficial for understanding and optimizing the functional property. Engineering of semiconductor photocatalyst was done by various techniques such as Schottky, Type-I, Type-II, and Type-III heterojunction formation, through which an efficient photocatalyst retarding the demerits (optical property, spatial charge distribution, recombination, etc.) faced by normal (non-heterojunction) semiconductor photocatalyst can be obtained. The basic principle behind heterojunction formation and its utilization was discussed. The synergistic effect between two different materials significantly impacted their photocatalytic activity improvement. In this review, we have exemplified the purpose of heterojunction formation, their types, and the band potential findings necessary for evaluating semiconductors' ability for the redox process. Furthermore, the future perspective for enhanced photocatalytic material design providing a newer pathway for upcoming research works was provided.
Graphical Abstract
The heterogeneous photo-Fenton system using Fe-Co/γ-Al2O3 as a catalyst was applied in the study of sulfamethoxazole(SMX) degradation. The morphology, structure, elemental composition and metal valence distribution of Fe-Co/γ-Al2O3 were found to be relatively stable before and after the reaction. The highest SMX degradation efficiency and mineralization (The ratio of organic matter being oxidized to carbon dioxide and water) were obtained under the conditions of 15% Fe-Co loading rate, 1:1 mass ratio of Fe and Co, 1 g/L catalyst dosage, 1.5 mL 30% H2O2 dosage, 18 W UV lamp power and 60 min reaction time, which were 98% and 66%, respectively. Radical quenching experiments and electronic paramagnetic resonance (EPR) characterization revealed that ·OH played an important role in the degradation and mineralization SMX in the Fe-Co/γ-Al2O3 heterogeneous photo-Fenton system. Combined with the analysis of N, S and intermediate products, there may be three degradation pathways of SMX in the heterogeneous photo-Fenton system. This work provides a technical reference for realizing the efficient degradation and mineralization of SMX in a heterogeneous photo-Fenton reaction system.
Since ancient times, sunlight irradiation has been widely used for water purification. Apart from solar water disinfection techniques, UV irradiation is of particular interest when considering the photodegradation of various classes of emerging pollutants. Pharmaceutically active compounds are one of the largest classes of micropollutants. The main sources of these contaminants in wastewater and aqueous environments are households, hospitals, manufacturing plants, and improper disposal of expired drugs. It is estimated that the pharmaceutical market in the European Union comprises about 3000 active compounds, and this number is constantly growing. Conventional wastewater treatment procedures based mainly on the activated sludge method are not suitable for poorly biodegradable pharmaceuticals. Good alternatives are advanced oxidation processes (AOPs) and especially photochemical-based processes (PAOPs). These methods involve the combination of UV light with various oxidizing agents, like hydrogen peroxide, ozone treatment, Fenton systems, and heterogeneous photocatalysis. One of the main disadvantages of many photochemical processes is relatively high cost. Moreover, UV treatment can lead to the formation of toxic intermediates. For this reason, extensive research on the pharmaceuticals’ photoinduced degradation paths has been carried out.
The oxidation of sulphamethoxazole medicine (SMX) has been studied by means of UV/H2O2 conducting at a controlled pH between 2.0 and 12.0 and oxidant ratios of 500 mol H2O2/mol SMX. It is verified that operating at pH = 2.0 the highest rates of SMX degradation (74%) and loss of aromaticity (64%) are obtained. During the process, a strong brown tint and high turbidity are generated in the water depending on the pH, as it affects the chemical speciation of the dissociable compounds. The colour intensity of the water increases from pH = 2.0 (light brown, 3.5 NTU) to a maximum value at pH = 4.0 (dark brown, 42 NTU), when the neutral SMX species is almost 100%. Under these conditions, the formation of carboxylic acids (acetic and oxalic) and nitrate ion are minor. Conducting at higher pH, hue decreases, obtaining at pH = 12.0 a light yellow water (5 NTU) when the anionic SMX predominates. Thus, the maximum formation of nitrate ion occurs under these conditions. A pseudo-first order kinetic modelling is proposed for the loss of aromaticity and colour and turbidity formation in water, where the kinetic parameters are expressed as a function of the applied pH, being the pseudo-first-order rate constants (min-1): karom=0.0005pH2-0.0106pH+0.0707; kcolour=0.0011pH2-0.02pH+0.1125 and kNTU = 0.06 min-1.
Ibuprofen (IBP) is one ubiquitous drug prescribed as anti-inflammatory, analgesic, and antipyretic. It has been detected in effluents of wastewater plant treatments, sewage sludge, hospital wastewaters, surface waters, and drinking water due to its continuous release to the environment, mainly from the excretion in the urine of animals and humans. IBP is a carcinogenic and non-steroidal endocrine disrupting drug with harmful effects over fungal, bacterial, algae, microorganisms, crustacean, and fish species, and can be potentially hazard for human health. Since conventional treatments remove inefficiently this drug, many advanced oxidation processes (AOPs) have been developed aiming their abatement from waters to avoid their harmful health problems. This paper presents an exhaustive and critical review on the application of AOPs to treat synthetic waters, natural waters, and real wastewaters polluted with IBP alone or mixed with other common drugs covering up to 2020. The characteristics and main results obtained for single, hybrid, and sequential treatments are described. Dielectric barrier or pulsed-corona discharges are detailed among the single processes. Hybrid processes such as photocatalysis (UV/H2O2, UV/chlorine, TiO2/UV), hybrid ozonation (O3/H2O2, electro-peroxone, catalytic ozonation), Fenton-based processes (photo-Fenton, electro-Fenton, photoelectro-Fenton), zero-valent iron, ultrasonic, peroxymonosulfate, and persulfate, are discussed. The effect of the kind of irradiation (UV, visible, solar) on photo-assisted processes is analyzed. Sequential processes with biological pre- or post-treatments using or not membranes for natural water and real wastewater remediation are described. Finally, 38 by-products detected during IBP removal by AOPs are reported, allowing envisaging three parallel pathways for its initial degradation.
In this study, a Janus Fe/C3N4 micromotor driven by a chromate-hydrogen peroxide (Cr(VI)-H2O2) redox system was developed and its movement was analyzed. The motion of the micromotor was tracked via nanoparticle tracking analysis (NTA) and the corresponding diffusion coefficients (D) were determined. The NTA results revealed that D = 0 in water in the absence of additives (Cr(VI) or H2O2). The addition of H2O2 resulted in an increase in D from 0 to 12 × 10⁶ nm² s⁻¹, which further increased to 20 × 10⁶, 26.5 × 10⁶, 29 × 10⁶, and 44 × 10⁶ nm² s⁻¹ with the addition of 0.5, 1, 2, and 5 ppm of Cr(VI), respectively. Cr(VI) alone did not efficiently propel the Fe/C3N4-based micromotor. Therefore, it was proposed that the Cr(VI)/H2O2 redox system generates O2, which plays a major role in the movement of the C3N4-based micromotor. In addition, the formation of reactive species, such as •OH and ¹O2, was confirmed through electron spin resonance experiments. The reactive species efficiently degraded sulfamethaxazole (SMX), an organic pollutant, as demonstrated through degradation studies and product analyses. The effects of various parameters, such as H2O2 concentration, Cr(VI) concentration, and initial pH on the movement of micromotor and degradation of SMX were also documented.
Four common refractory pharmaceuticals, diclofenac (DF), sulpiride (SP), sulfamethoxazole (SMX) and sulfisomidine (SIM) were detected in the Disc Tubular Reverse Osmosis (DTRO) concentrates with higher concentrations ranging from 0.85 to 11.57 μg/L from the local landfill. The effect of complex matrix of DTRO concentrates on the UV-Fenton degradation kinetics of DF, SP, SMX and SIM and their transformation products (TPs) were studied. All the four pharmaceuticals could be degraded more efficiently in the ultrapure water than that in the DTRO-concentrate matrix, which also had a significant negative effect on the kinetic constants of the degradation. Twenty-two out of forty-nine TPs were newly identified by HPLC-QTOF-MS and their peak-area evolution was presented. The main degradation pathways for four pharmaceuticals were identified. When assessing cytotoxicity by using HepG2 cells, there appeared to be an obvious toxicity-increase region for each of SP, SMX and SIM. Eleven TPs were identified as the potential toxicity-increase causing TPs by combination of the QSAR prediction, HepG2 cytotoxicity assessment and peak-area evolution of TPs. Therefore, UV-Fenton process was a promising method for the refractory pharmaceutical degradation even in the complex water matrix and choosing appropriate reaction parameters for the UV-Fenton could eliminate the cytotoxicity of the TPs.
To improve the cycle between Fe³⁺ and Fe²⁺ in persulfate (PS) Fenton-like system, sulfite (Na2SO3) was used as the iron complexing agent to enhance the degradation of sulfamethoxazole (SMX) antibiotic in water. Response surface methodology (RSM) was applied to regulate the operation parameters for the Fe³⁺/Na2SO3/PS synergistic system. Based on the RSM, the SMX could be completely degraded when the concentration of Fe³⁺, Na2SO3, and PS were 0.4, 0.5, and 2.5 mM, respectively. The result showed that the synergistic process represented a high Fe³⁺ utilization rate and SMX degradation efficiency. After 1 h reaction, 100.00% of SMX and 27.80% of total organic carbon were removed under the ambient conditions containing the initial SMX concentration of 10 μM and initial pH of 5.96. Free radical masking and electron spin-resonance tests proved that hydroxyl radical (HO) and oxysulfur radicals (SOx⁻, x = 3, 4, 5) were all played the significant role in the antibiotic removal, and the primary active radical was HO. The SMX decomposition pathways based on the formed intermediates was proposed through the high-performance liquid chromatography and mass spectrum analyses. The toxicity assessment prediction indicated that the toxicities of decomposed SMX byproducts were reduced after the coupling treatment.
This study compared the degradation efficiency of diatrizoate (DTA) by UV/chlorine and UV/chloramine processes. DTA could be effectively degraded by the UV/chlorine and UV/chloramine processes compared with chlorination and chloramination solely. Although the UV/chlorine process was more sensitive to the variations of oxidant dosages, solution pH, the concentration of bicarbonate and chloride, UV/chlorine degraded DTA more efficiently than UV/chloramine process. The reactive chlorine species (RCS) and hydroxyl radical (HO) are predominant contributors to DTA degradation in the UV/chlorine and UV/chloramine processes respectively, and the specific contribution of each reactive specie changed with solution pH. The performance of UV/chlorine and UV/chloramine processes on DTA degradation was obviously inhibited in natural waters (e.g., wastewater, rainwater, river water and tap water), however, degradation of DTA in the UV/chlorine are still satisfactory compared with UV/chloramine process. Formation of chloroform, dichloroacetonitrile, and iodoform (IF) from DTA was observed in both UV/chlorine and UV/chloramine processes. It is notable that formation potential of IF from DTA was significantly enhanced in UV/chloramine process, and thus the overall cytotoxicity of generated DBPs in UV/chloramine process is far greater than that in UV/chlorine process.
This paper manifests the potential viability of soil as a cost-free catalyst in photo-Fenton-like processes for treating pharmaceuticals at large scale. Naturally available soil without any cost intensive modification was utilized as a catalyst to degrade pharmaceuticals, specifically ornidazole (ORZ) and ofloxacin (OFX). Soil was characterized and found enriched with various iron oxides like hematite, magnetite, goethite, pyrite and wustite, which contributes toward enhanced dissolution of Fe(3+) than Fe(2+) in the aqueous solution resulting in augmented rate of photo-Fenton reaction. The leached iron concentration in solution was detected during the course of experiments. The degradation of ORZ and OFX was assessed in solar induced batch experiments using H2O2 as oxidant and 95% ORZ and 92% OFX removal was achieved. Elevated efficiencies were achieved due to Fe(2+)/Fe(3+) cycling, producing more hydroxyl radical leading to the existence of homogeneous and heterogeneous reactions simultaneously. The removal efficiency of solar photo-Fenton like process was also compared to photo-Fenton process with different irradiation sources (UV-A and UV-B) and were statistically analysed. Continuous-scale studies were conducted employing soil either in the form of soil beads or as a thin layer spread on the surface of baffled reactor. Soil beads were found to have satisfactory reusability and stability. 84 and 79% degradation of ORZ and OFX was achieved using soil as thin layer while with soil beads 71 and 68% degradation, respectively. HPLC and TOC study confirmed the efficient removal of both the compounds. Toxicity assessment demonstrates the inexistence of toxic intermediates during the reaction.
Today, the presence of contaminants in the environment is a topic of interest for society in general and for the scientific community in particular. A very large amount of different chemical substances reaches the environment after passing through wastewater treatment plants without being eliminated. This is due to the inefficiency of conventional removal processes and the lack of government regulations. The list of compounds entering treatment plants is gradually becoming longer and more varied because most of these compounds come from pharmaceuticals, hormones or personal care products, which are increasingly used by modern society. As a result of this increase in compound variety, to address these emerging pollutants, the development of new and more efficient removal technologies is needed. Different advanced oxidation processes (AOPs), especially photochemical AOPs, have been proposed as supplements to traditional treatments for the elimination of pollutants, showing significant advantages over the use of conventional methods alone. This work aims to review the analytical methodologies employed for the analysis of pharmaceutical compounds from wastewater in studies in which advanced oxidation processes are applied. Due to the low concentrations of these substances in wastewater, mass spectrometry detectors are usually chosen to meet the low detection limits and identification power required. Specifically, time-of-flight detectors are required to analyse the by-products.
The study is about a novel method of decomposing and mineralizing the emerging contaminant ibuprofen (IBP) by catalytic ozonation using catalysts such as high-frequency ultrasound (US) and soluble/insoluble Fe-bearing species. Preliminary experiments with single processes were run to select the optimum values of IBP concentration, O3 flow rate and specific US power as 50 uM, 12mgmin−1,and 0.23 WmL−1, respectively. It was found that the most critical operation parameter was pH, as it controlled the mass transfer and decomposition of O3, as well as the diffusion of solutes from the bulk solution to the gas–liquid
and solid–liquid interfaces. As such, ozonation and sonication alone were most effective at pH 9.0 and 3.0, respectively owing to the higher rate of •OH production and gas–liquid interfacial reactions at these conditions. Catalytic ozonation with Fe-bearing species but no ultrasound was most effective at pH 6.5, with
a maximum degree of IBP decay in the presence of FeSO4. Catalytic ozonation with ultrasound and solid particles was effective at pH 6.5, but maximum degree of oxidation/mineralization was obtained with nanoparticles of zero-valent iron (ZVI) at pH 3.0 (100%,58%). The synergy of US+ZVI at acidic pH was attributed to: (i) the massive surface areas enriched with extensive reaction and nucleation sites, (ii) the role
of reactive Fe (furnishing out from the metal core onto the catalyst surface) and reactive oxygen species as promoters of Fenton-like reactions, and (iii) the contribution of hydrodynamic shear forces to continuous enhancement and cleaning of the catalytic surfaces.
The efficiency of ozonation and advanced oxidation processes such as ozone/UV, ozone/H2O2 and H2O2/UV was assessed for chlorinated hydrocarbons using a closed batch-type system. 1,1-Dichloropropene (DCPE), trichloroethylene (TCE), 1-chloropentane (CPA), and 1,2-dichloroethane (DCA) were used as model compounds.The direct reaction between substrates and ozone predominated at lower pH, which resulted in the efficient oxidation of the olefin, DCPE. At higher pH, ozonation resulted in more efficient oxidation of the chlorinated alkanes, with a corresponding decrease in the efficiency of DCPE oxidation. Consistent results were observed for ozone/H2O2 and ozone/UV treatment. Due to slow UV-induced decomposition of H2O2, the process using H2O2/UV (254 nm) resulted in very slow oxidation of all four compounds.The total ozone requirement to achieve a given degree of elimination (to 37% of the original concentration), δ0.37, was used to assess the combined effects of the direct and indirect reactions for different types of waters.
Aqueous photocatalytic oxidation (PCO) of a non-biodegradable sulphonamide antibiotic sulfamethizole was studied. The impacts of photocatalyst dose, initial pH, and substrate concentration in the range from 1 to 100 mg L(-1) were examined with a number of organic and inorganic by-products determined, suggesting the initial break-up of the SMZ molecule at the sulphonamide bond. The experiments were carried out under artificial near-UV and visible light, and solar radiation using Degussa P25 and less efficient visible light-sensitive C-doped titanium dioxide as photocatalysts.
The occurrence of analgesics in the environment can be explained by the fact that they are very popular and in common use, for example: to treat the symptoms of colds, aches and pains or for the treatment of painful diseases of rheumatic and non-rheumatic origin. Analgesic drugs are only partly removed from wastewater using the biological wastewater treatment processes. The photochemical methods are mentioned as a useful tool for the removal of analgesic medicines from the aquatic environment. The elimination of three analgesic drugs: diclofenac, naproxen and ibuprofen from the aquatic environment using UV- and UV/H(2)O(2)-processes was the aim of the study. All experiments were performed in the water with the presence and the absence of the urea as the main urine component. With the presence of urea the values of photo-oxidation rate constants (in the UV/H(2)O(2)-process) varied from 0.22 min(-1) (ibuprofen) to 0.39 min(-1) (diclofenac). The values of the photodegradation rate constants in the solution without urea (in the UV/H(2)O(2)-process) varied from 0.25 min(-1) (ibuprofen) to 0.45 min(-1) (diclofenac). The study showed that naproxen, ibuprofen and diclofenac may be effectively removed from the aquatic environment (e.g. from the urine) by means of photochemical methods.
Over the past few years, pharmaceuticals are considered as an emerging environmental problem due to their continuous input and persistence to the aquatic ecosystem even at low concentrations. Advanced oxidation processes (AOPs) are technologies based on the intermediacy of hydroxyl and other radicals to oxidize recalcitrant, toxic and non-biodegradable compounds to various by-products and eventually to inert end-products. The environmental applications of AOPs are numerous, including water and wastewater treatment (i.e. removal of organic and inorganic pollutants and pathogens), air pollution abatement and soil remediation. AOPs are applied for the abatement of pollution caused by the presence of residual pharmaceuticals in waters for the last decade. In this light, this paper reviews and assesses the effectiveness of various AOPs for pharmaceutical removal from aqueous systems.
Acid solutions containing up to 1 g l−1 of the drug paracetamol have been treated with ozone alone and ozonation catalyzed with Fe2+, Cu2+ and/or UVA light at 25.0 °C. Direct ozonation yields poor degradation due to the high stability of final carboxylic acids formed, whereas more than 83% of mineralization is attained with the catalyzed methods. Under UVA irradiation, organics can be efficiently destroyed by the combined action of generated H2O2 and UVA light. In the presence of Fe2+ and UVA light, the process is accelerated due to the production of oxidant hydroxyl radical (OH) and the photodecomposition of Fe3+ complexes. The highest oxidizing power is achieved by combining Fe2+, Cu2+ and UVA light, because complexes of final acids with Cu2+ are more quickly degraded than those competitively formed with Fe3+. For all catalyzed methods, the initial mineralization rate is enhanced and the percent of degradation generally drops with increasing drug concentration. The paracetamol decay always follows a pseudo-first-order reaction with slightly higher rate constant for catalyzed systems than direct ozonation. Aromatic products such as hydroquinone, p-benzoquinone and 2-hydroxy-4-(N-acetyl)aminophenol are identified by gas chromatography–mass spectrometry (GC–MS) and reversed-phase chromatography. Acetamide is generated when hydroquinone is produced. These products are degraded to oxalic and oxamic acids as ultimate carboxylic acids, as detected by GC–MS and ion-exclusion chromatography. Oxalic acid is generated via glycolic, glyoxylic, tartronic, ketomalonic and maleic acids. While Fe3+-oxalato complexes are photolyzed by UVA light, Cu2+-oxalato, Fe3+-oxamato and Cu2+-oxamato complexes are oxidized with OH. NH4+ and NO3− ions are produced during mineralization.
The electrochemical oxidation of Ibuprofen (Ibu) was performed using a Ti/Pt/PbO2 electrode as the anode, prepared according to literature, and a boron doped diamond (BDD) electrode, commercially available at Adamant Technologies. Tests were performed with model solutions of Ibu, with concentrations ranging from 0.22 to 1.75 mM for the Ti/Pt/PbO2 electrode and 1.75 mM for the BDD electrode, using 0.035 M Na2SO4 as the electrolyte, in a batch cell, at different current densities (10, 20 and 30 mA cm−2). Absorbance measurements, Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) tests were conducted for all samples. The results have shown a very good degradation of Ibu, with COD removals between 60 and 95% and TOC removals varying from 48 to 92%, in 6 h experiments, with higher values obtained with the BDD electrode. General Current Efficiency and Mineralization Current Efficiency, determined for both electrodes, show a similar behaviour for 20 mA cm−2 but a very different one at 30 mA cm−2. The combustion efficiency was also determined for both anodes, and found to be slightly higher with BDD at lower current density and equal to 100% for both anodes at 30 mA cm−2.
The influence of water quality parameters (dissolved organic matter and alkalinity) on the efficiency of the ozone/hydrogen peroxide (O 3/H 2O 2) advanced oxidation process (AOP) relative to the corresponding conventional ozonation process was investigated. In natural waters with a high natural organic matter content (≥3 mg/L), O 3 decomposition is controlled by radical-type chain reactions. Thus, the overall OH radical oxidation capacity is nearly independent if conventional ozonation is replaced by O 3/H 2O 2 AOP. In contrast, when the organic matter content in the natural water is low (≤1 mg/L), the addition of H 2O 2 considerably enhances the oxidation capacity by OH radicals. A constant ratio between the OH radical and O 3 concentration (R Cτ) was found during both treatments, making it possible to predict the oxidation of micropollutants with O 3 and OH radicals if the rate constants of both oxidants are known. The oxidation of atrazine during ozonation and the combined process O 3/H 2O 2 could be accurately predicted in natural waters.
This study focused on the degradation of the worldwide Non-steroidal Anti-Inflammatory Drug (NSAID) ibuprofen (IBP) by gamma irradiation. Factors affecting IBP degradation efficiency were examined. The results showed that IBP concentration decreased with an increasing absorbed dose. When IBP concentration of 28.3mg/L and an absorbed dose of 1.1kGy were chosen, IBP degradation value was 100%. The degradation process of IBP could be depicted by first order reaction kinetics when the absorbed dose was less than 0.9kGy. 0.1% H2O2 and humic acid additives enhanced IBP degradation process, while 0.5% H2O2 additive restrained the degradation of IBP. The additions of CO32−, NO3−, CH3OH and thiourea restrained the degradation process. The pH value affected the IBP degradation. The degradation efficiency was more efficient under acidic condition than in neutral or alkaline media. The solution pH value became lower with increasing absorbed dose after gamma irradiation. High performance liquid chromatography (HPLC) and electrospray ionisation mass spectrometry (ESMS) techniques were employed to identify the IBP derivatives. The mono- and quadric-hydroxylated of IBP and the products due to the oxidation of propanoic acid, and isobutyl substituents of IBP were identified.
Environmentally relevant pharmaceuticals were chosen according to human consumption and occurrence in the aquatic environment like sewage plant effluents, rivers and groundwater to investigate their behavior during oxidative water treatment. Derived from data compilation in literature the lipid lowering agent clofibric acid and the analgesic agents ibuprofen and diclofenac were selected. Analyses of the acidic compounds were carried out after solid-phase extraction and online derivatization in the GC injector by means of single ion monitoring (SIM) GC/MS. Oxidation experiments with the aim to degrade the pharmaceuticals were carried out in bench scale using ozone and ozone/hydrogen peroxide (advanced oxidation process). Under the specific reaction conditions only diclofenac was degraded by ozone to about 3% of its initial concentration. The combined application of ozone and hydrogen peroxide leading to OH-radical formation improved the degradation efficiency of all investigated compounds. The application of increased oxidant concentration resulted in a better degradation of all compounds to more than 90% at a concentration of 3.7 mg l−1 ozone and 1.4 mg l−1 hydrogen peroxide and to more than 98% at a concentration of 5.0 mg l−1 ozone and 1.8 mg l−1 hydrogen peroxide. At the applied conditions no reaction products could be detected by GC/MS analyses after derivatization of acidic functional groups.
First, the effect of ferrioxalate or iron nitrate on the photo-Fenton degradation efficiency of the pharmaceuticals lincomycin (LCM) and diazepam (DZP) was evaluated. The degradation of both pharmaceuticals was improved in the presence of ferrioxalate in relation to Fe(NO3), either under black-light or solar irradiation. The degradation of the pharmaceuticals was then evaluated when present in an effluent from sewage treatment plant (STP) under black-light irradiation. Pharmaceuticals oxidation was not influenced by the matrix, since very similar results were obtained when compared to the experiments carried out in distilled water. However, DOC removal was slightly affected by the matrix, due probably to the generation of recalcitrant intermediates during effluent photodegradation and to the high content of inorganic carbon of STP effluent. Even so, high DOC removal percentages were achieved, 65% for lincomycin and 80% for diazepam after 60min irradiation.
The degradation of a 41mgdm−3 ibuprofen (2-(4-isobutylphenyl)propionic acid) solution of pH 3.0 has been comparatively studied by electrochemical advanced oxidation processes (EAOPs) like electro-Fenton, UVA photoelectro-Fenton and solar photoelectro-Fenton at constant current density. Experiments were performed in a one-compartment cell with a Pt or boron-doped diamond (BDD) anode and an O2-diffusion cathode. Heterogeneous hydroxyl radical (OH) is generated at the anode surface from water oxidation, while homogeneous OH is formed from Fenton's reaction between Fe2+ and H2O2 generated at the cathode, being its production strongly enhanced from photo-Fenton reaction induced by sunlight. Higher mineralization is attained in all methods using BDD instead Pt, because the former produces greater quantity of OH enhancing the oxidation of pollutants. The mineralization rate increases under UVA and solar irradiation by the rapid photodecomposition of complexes of Fe(III) with acidic intermediates. The most potent method is solar photoelectro-Fenton with BDD giving 92% mineralization due to the formation of a small proportion of highly persistent final by-products. The effect of Fe2+ content, pH and current density on photoelectro-Fenton degradation has been studied. The ibuprofen decay always follows a pseudo-first-order kinetics and its destruction rate is limited by current density and UV intensity. Aromatics such as 1-(1-hydroxyethyl)-4-isobutylbenzene, 4-isobutylacetophenone, 4-isobutylphenol and 4-ethylbenzaldehyde, and carboxylic acids such as pyruvic, acetic, formic and oxalic have been identified as oxidation by-products. Oxalic acid is the ultimate by-product and the fast photodecarboxylation of its complexes with Fe(III) under UVA or solar irradiation explains the higher oxidation power of photoelectro-Fenton methods in comparison to electro-Fenton procedures.
The mineralization of antibiotic sulfamethoxazole (SMX) of concentrations up to 300mgL−1 was examined by photoelectro-Fenton (PEF) using an activated carbon fiber (ACF) cathode with UVA (365nm) irradiation. Comparative mineralization has been studied by different methods: RuO2/Ti anodic oxidation (AO), AO in the presence of electrogenerated H2O2 (AO-H2O2), AO-H2O2 in the presence of UVA (AO-H2O2-UVA), and both the electro-Fenton (EF) and PEF processes. PEF treatment at a low applied current of 0.36A yields a faster and more complete depollution with 80% of the TOC removed after 6h of electrolysis. The higher oxidative ability of the PEF process can be attributed to the additional hydroxyl radicals (OH) produced by the photo-Fenton reaction. The 63% mineralization in the case of EF treatment was due to the formation of short intermediates, such as carboxylic acids, which were difficult to oxidise with OH. In the AO-H2O2-UVA process, about 36% of the TOC was removed after 6h electrolysis, while 28% of the TOC was removed in the AO-H2O2 process. SMX is only slightly mineralized by the AO process, with only 25% of the TOC removed. HPLC–MS analysis allowed for up to six aromatic reaction products to be identified during the SMX degradation in the PEF process, mainly formed from the hydroxylation of the aromatic ring or/and isoxazole ring, accompanied by the substitution of the amine group (on aromatic cycle) or methyl group (on isoxazole ring) by OH. The carboxylic acids generated, including oxalic, maleic, oxamic, formic and acetic acids, were detected by ion-exclusion chromatography. The initial organic nitrogen was mainly converted into NH4+ along with a very small proportion of NO3− ion. Considering all the oxidation intermediates and end products for SMX degradation in the PEF process, a general mineralization mechanism by OH and UVA was proposed.
The capital and operating costs for several aromatic compounds (phenanthrene, 2,4-dimethylphenol, 2,4,6-trichlorophenol, nitrobenzene) removal from polluted groundwater using ozonation and advanced oxidation have been estimated on the basis of the laboratory experiments in semibatch conditions. The pollutants initial concentration was in the range of 0.01–1.0 mM. In the calculations the polluted groundwater flow rate was taken 40 m/h with the initial pH = 7.0. It is shown that polluted groundwater purification from the aromatic pollutants with the initial concentration in the range of 0.01–1.0 mM using ozonation and advanced oxidation is economically feasible.
The quantum yield for the photolysis of hydrogen peroxide by 2537 Å light in 0.10 N perchloric acid is found to be 1.00 at 25°C and is independent of concentration and light intensity over the ranges studied, viz., 2 x 10-5 to 0.1 M peroxide and 4.5 x 10-6 to 5 x 10 -4 einstein l.-1 min-1. The yield falls to 0.80 at 4°C. The ion HO2- gives the same yields as H 2O2 at these temperatures. The presence of Cu2+ introduces a chain reaction in otherwise non-chain conditions. From this it is inferred that in the non-chain decomposition HO2 is an intermediate and the observed quantum yield is twice the primary yield. In the absence of air, formic acid, carbon monoxide, ethanol and isopropanol also induce the chain decomposition of hydrogen peroxide. On the other hand acetic acid decreases the quantum yield until it reaches 0.50 when it is independent of acetic acid concentration. This is considered additional evidence that the primary yield is 0.50 at 25°C. In the presence of air all the organic compounds reduce the quantum yield to less than 0.50, which means that peroxide is regenerated in these conditions.
The aim of this study is the evaluation of photocatalysis to degrade two antibiotics widely used in both human and veterinary medicine: sulfamethoxazole (SMX) and trimethoprim (TMP), in aqueous medium. The degradation of SMX and TMP, and the TOC reduction, were improved when TiO2 concentration was increased, up to 0.5 and 0.2–0.5g TiO2L−1 in the case of SMX and TMP, respectively, where the scattering phenomena start being noticeable. The comparison between photocatalysis and photolysis shows that the SMX degradation is improved when the catalyst is present in the solution. In the case of TMP, the final degradation achieved by the two processes is similar, but the evolution during time can be clearly differentiated, indicative of different reaction pathways. Surprisingly, when monitoring the aromatic content during TMP photocatalysis, this increases to a large extent during the first 3h. On the contrary, the photocatalytic degradation of SMX results in a gradual cleavage of the molecule, because the aromatic content decreases gradually during the photocatalytic reaction (72%). Finally, the experimental data of both antibiotics were fitted to a simple model, taking into account the effect of the radiation on the kinetic constants.
The stoichiometry of Fenton's reagent in the oxidation of dichloroethylene (DCE), trichloroethylene (TCE), tetrachloroethylene (tetra-CE), and dichloroethane (DCEA) was investigated. The theoretical optimal ratio between H2O2 and Fe2+ is found to be 11. However, the experimentally determined optimal ratio between H2O2 and Fe2+ ranged from 5 to 11 at optimal pH of 3.5. The amount of H2O2 required for a specific percentage removal of the organic compounds depends upon the initial organic concentration to be oxidized. The accumulation of chloride ion released also depends upon the initial organic substance concentrations. The typical percentage removal of organic compounds and percentage release of chloride ion were reported at 100%, 70%, 50%, 40%, 30%, 20%, 10%, and 1%. The amount of H2O2 required to achieve a certain percentage removal follows the order of TCE < Tetra-CE < DCE << DCEA. However, the amount of chloride ion detected at a constant concentration of H2O2 follows the order of DCEA << DCE < TCE < Tetra-CE.
The purpose of this study was to develop a municipal wastewater treatment method based on a solar advanced oxidation process (AOP) permitting reuse of the treated wastewater. The photoactive layer of TiO2 was deposited on glass spheres using the sol–gel dip-coating technique. The film was characterized by X-ray diffraction and scanning electron microscopy (SEM). Degradation of 15 emerging contaminants (ECs), each with an initial concentration of 100 μg L−1 was determined by ultra-performance liquid chromatography (UPLC–UV) and mineralization was monitored by measuring the dissolved organic carbon (DOC). The experiments were performed in a pilot compound parabolic collector (CPC) solar plant at the Plataforma Solar of Almeria. Five cycles of photocatalysis were studied for photocatalyst durability and activity. It was demonstrated that after five cycles, although photoactivity of the catalyst slowly decreases, it continues degrading contaminants.
Ozonation of sulfamethoxazole promoted by a powder activated carbon (PAC) of neutral nature has been studied for mechanistic and kinetic purposes. The main advantage of using powder activated carbon was the removal of both liquid–solid and internal diffusion mass transfer resistances. In addition, at the operational conditions applied the influence of the gas–liquid mass transfer was eliminated. As a result, in the absence of any physical mass transfer resistances, a mechanism that involves both homogenous and heterogeneous reactions for the mineralization of the water matrix was proposed and a mathematical kinetic model was obtained from the corresponding mass balances of main species present. In order to properly solve the kinetic model a term indicative of the changing nature of the water matrix was introduced. In that way the promoting or non-promoting character of water constituents was considered in the mechanism.
The photocatalytic degradation of sulfanilamide, sulfacetamide, sulfathiazole, sulfamethoxazole and sulfadiazine in aqueous solutions was examined during their irradiation with UV-A (366 nm) with TiO2, Fe salts and TiO2/FeCl3 catalysts. The study was carried out by HPLC-UV, HPLC/MS-EI and total organic carbon (TOC) methods.It was found that sulfonamides underwent photocatalytic degradation in the presence of TiO2, TiO2/FeCl3 and Fe3+ salts, and the optimum catalyst for this process can be FeCl3. Based on the identified intermediate products, a degradation pathway was proposed. Moreover, the rate of photocatalytic process carried out with FeCl3 as well as the relationship between the pH of irradiated solutions, initial concentrations of sulfanilamide and FeCl3 were stated.
The purpose of this study was to propose a municipal wastewater treatment method based on solar Advanced Oxidation Processes (AOPs) permitting reuse of the treated wastewater. Experiments were performed in a pilot compound parabolic collector (CPC) solar plant at the Plataforma Solar de Almería. Mineralisation was monitored by measuring the dissolved organic carbon (DOC), and the concentration profile of each compound during degradation was determined by HPLC–UV. Two different approaches, photo-Fenton (pH = 2.8) and TiO2 were tested with 9 different emerging contaminants at 100 μg L−1 each (acetaminophen, antipyrine, atrazine, caffeine, diclofenac, isoproturon, progesterone, sulfamethoxazole, and triclosan) at low iron and TiO2 concentrations. Photo-Fenton was by far more effective than TiO2 for degrading these contaminants, and was therefore selected for further study. The 9 contaminants were tested under the following conditions without pH adjustment: (i) Fe = 5 mg L−1, D.I. water; (ii) Fe = 5, 15 and 55 mg L−1, standard fresh water; (iii) Fe = 5 mg L−1, standard fresh water without NaHCO3. Initial amount of hydrogen peroxide was 50 mg L−1, frequently analysed and added to maintain this concentration. It was demonstrated that low efficiency in some cases is mainly due to bicarbonates, and it is therefore proposed that the process be improved, either by increasing the iron concentration, or eliminating bicarbonates.
Comprehensive lists of rate constants of reactions of ozone with acidic and basic organic chemicals dissolved in water, such as amines, amino acids, carboxylic acids and phenols are reported. The second-order rate constants increase with pH as does the degree of deprotonation of the dissolved substances, e.g. from 1 to 100 M−1 s−1 for formic acid, from 0.2 to 2 M−1 s−1 for glyoxalic acid and from 103 to 109 M−1 s−1 for phenolic compounds. All results support the conclusions presented in Part 1 for the electrophilic reactions of ozone with non-dissociating compounds. They are important for the understanding of the pH dependence of the rate and selectivity of ozonation reactions and for explaining the chemical effects of ozone on impurities in drinking water and waste waters.
This study investigates the oxidation of pharmaceuticals, endocrine disrupting compounds and pesticides during ozonation applied in drinking water treatment. In the first step, second-order rate constants for the reactions of selected compounds with molecular ozone (kO3) were determined in bench-scale experiments at pH 8.10: caffeine (650 ± 22 M−1 s−1), progesterone (601 ± 9 M−1 s−1), medroxyprogesterone (558 ± 9 M−1 s−1), norethindrone (2215 ± 76 M−1 s−1) and levonorgestrel (1427 ± 62 M−1 s−1). Compared to phenolic estrogens (estrone, 17β-estradiol, estriol and 17α-ethinylestradiol), the selected progestogen endocrine disruptors reacted far slower with ozone. In the second part of the study, bench-scale experiments were conducted with surface waters spiked with 16 target compounds to assess their oxidative removal using ozone and determine if bench-scale results would accurately predict full-scale removal data. Overall, the data provided evidence that ozone is effective for removing trace organic contaminants from water with ozone doses typically applied in drinking water treatment. Ozonation removed over 80% of caffeine, pharmaceuticals and endocrine disruptors within the CT value of about 2 mg min L−1. As expected, pesticides were found to be the most recalcitrant compounds to oxidize. Caffeine can be used as an indicator compound to gauge the efficacy of ozone treatment.
Photodegradation of the pharmaceuticals amoxicillin (AMX), bezafibrate (BZF) and paracetamol (PCT) in aqueous solutions via the photo-Fenton process was investigated under black-light and solar irradiation. The influences of iron source, initial H2O2 concentration and matrix (distilled water and sewage treatment plant effluent) on degradation efficiency were discussed in detail. The results showed that (i) the degradation of the drugs was favored in the presence of potassium ferrioxalate (FeOx) in comparison to Fe(NO3)3; (ii) the increase of the H2O2 concentration improved the efficiency of AMX and BZF oxidation; however, the same was not observed for PCT; (iii) the influence of the matrix was observed for the degradation of BZF and PCT; (iv) under solar irradiation, the oxidation of the BZF and PCT is faster than under black-light irradiation. All these pharmaceuticals can be efficiently degraded employing the process evaluated.
Solutions of the veterinary fluoroquinolone antibiotic enrofloxacin in 0.05 M Na2SO4 of pH 3.0 have been comparatively degraded by electrochemical advanced oxidation processes such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), photoelectro-Fenton (PEF) and solar photoelectro-Fenton (SPEF) at constant current density. The study has been performed using an undivided stirred tank reactor of 100 ml and a batch recirculation flow plant of 2.5 l with an undivided filter-press cell coupled to a solar photoreactor, both equipped with a Pt or boron-doped diamond (BDD) anode and a carbon–polytetrafluoroethylene gas diffusion cathode to generate H2O2 from O2 reduction. In EF, PEF and SPEF, hydroxyl radical (OH) is formed from Fenton's reaction between added catalytic Fe2+ and generated H2O2. Almost total decontamination of enrofloxacin solutions is achieved in the stirred tank reactor by SPEF with BDD. The use of the batch recirculation flow plant showed that this process is the most efficient and can be viable for industrial application, becoming more economic and yielding higher mineralization degree with raising antibiotic content. This is feasible because organics are quickly oxidized with OH formed from Fenton's reaction and at BDD from water oxidation, combined with the fast photolysis of complexes of Fe(III) with generated carboxylic acids under solar irradiation. The lower intensity of UVA irradiation used in PEF with BDD causes a slower degradation. EF with BDD is less efficient since OH cannot destroy the most persistent Fe(III)–oxalate and Fe(III)–oxamate complexes. AO-H2O2 with BDD yields the poorest mineralization because pollutants are only removed with OH generated at BDD. All procedures are less potent using Pt as anode due to the lower production of OH at its surface. Enrofloxacin decay always follows a pseudo first-order reaction. Its primary aromatic by-products and short intermediates including polyols, ketones, carboxylic acids and N-derivatives are detected by GC–MS and chromatographic techniques. The evolution of F−, NO3− and NH4+ ions released to the medium during each process is also determined.
Over the past few years, antibiotics have been considered emerging pollutants due to their continuous input and persistence in the aquatic ecosystem even at low concentrations. They have been detected worldwide in environmental matrices, indicating their ineffective removal from water and wastewater using conventional treatment methods. To prevent this contamination, several processes to degrade/remove antibiotics have been studied. This review addresses the current state of knowledge concerning the input sources, occurrence and mainly the degradation and removal processes applied to a specific class of micropollutants, the antibiotics. In this paper, different remediation techniques were evaluated and compared, such as conventional techniques (biological processes, filtration, coagulation, flocculation and sedimentation), advanced oxidation processes (AOPs), adsorption, membrane processes and combined methods. In this study, it was found that ozonation, Fenton/photo-Fenton and semiconductor photocatalysis were the most tested methodologies. Combined processes seem to be the best solution for the treatment of effluents containing antibiotics, especially those using renewable energy and by-products materials.
The energy consumptions of conventional ozonation and the AOPs O(3)/H(2)O(2) and UV/H(2)O(2) for transformation of organic micropollutants, namely atrazine (ATR), sulfamethoxazole (SMX) and N-nitrosodimethylamine (NDMA) were compared. Three lake waters and a wastewater were assessed. With p-chlorobenzoic acid (pCBA) as a hydroxyl radical ((•)OH) probe compound, we experimentally determined the rate constants of organic matter of the selected waters for their reaction with (•)OH (k(OH,DOM)), which varied from 2.0 × 10(4) to 3.5 × 10(4) L mgC(-1) s(-1). Based on these data we calculated (•)OH scavenging rates of the various water matrices, which were in the range 6.1-20 × 10(4) s(-1). The varying scavenging rates influenced the required oxidant dose for the same degree of micropollutant transformation. In ozonation, for 90% pCBA transformation in the water with the lowest scavenging rate (lake Zürich water) the required O(3) dose was roughly 2.3 mg/L, and in the water with the highest scavenging rate (Dübendorf wastewater) it was 13.2 mg/L, corresponding to an energy consumption of 0.035 and 0.2 kWh/m(3), respectively. The use of O(3)/H(2)O(2) increased the rate of micropollutant transformation and reduced bromate formation by 70%, but the H(2)O(2) production increased the energy requirements by 20-25%. UV/H(2)O(2) efficiently oxidized all examined micropollutants but energy requirements were substantially higher (For 90% pCBA conversion in lake Zürich water, 0.17-0.75 kWh/m(3) were required, depending on the optical path length). Energy requirements between ozonation and UV/H(2)O(2) were similar only in the case of NDMA, a compound that reacts slowly with ozone and (•)OH but is transformed efficiently by direct photolysis.
The UV (254 nm) and UV/VUV (254/185 nm) photolysis of two anti-inflammatory drugs, ibuprofen and ketoprofen, have been studied in aqueous solutions as a possible process for the removal of non-biodegradable compounds. We have examined the effects of dissolved oxygen and initial target concentration. Upon irradiation at 254 nm, the decomposition rate of ketoprofen is almost forty times higher as it of ibuprofen whilst VUV irradiation only increased the ibuprofen decomposition rate. The presence of dissolved oxygen accelerated the photodegradation of ibuprofen, whereas no effect was observed on the degradation of ketoprofen. The maximum quantum yield for the phototransformation was 0.2. The rate of mineralization in both cases was ∼60%, even after 1h of treatment and this suggests the formation of stable by-products which were identified using GC-MS and HPLC-MS, respectively.
The photolysis of two antibacterial compounds, sulfamethoxazole and trimethoprim, was studied in wastewater effluent. The rate of loss of sulfamethoxazole was enhanced in wastewater effluent due to indirect photolysis reactions, specifically reactions with hydroxyl radicals and triplet excited state effluent organic matter. Photolysis in the presence of natural organic matter, however, did not lead to enhanced degradation of sulfamethoxazole. Trimethoprim was also found to be susceptible to indirect photolysis in wastewater effluents, with hydroxyl radical and triplet excited effluent organic matter being the responsible species. Deoxygenation of solutions led to more rapid direct photolysis of sulfamethoxazole and trimethoprim, indicating that direct photolysis proceeds through a triplet excited state, which was verified by demonstrating that trimethoprim is a singlet oxygen sensitizer. In the wastewater effluents tested, photolysis could be apportioned into direct photolysis (48% for sulfamethoxazole, 18% for trimethoprim), reaction with hydroxyl radicals (36% and 62%, respectively) and reaction with triplet excited effluent organic matter (16% and 20%, respectively). These results indicate that allowing photolysis in wastewater stabilization ponds or wastewater treatment wetlands may lead to enhanced pharmaceutical removal prior to discharge and that effluent organic matter has different photoreactivity than natural organic matter.
The electrochemical abatement of the antibiotic sulfamethoxazole (SMX) from aqueous solutions at pH 3.0 has been carried out by anodic oxidation and electro-Fenton (EF) processes with H(2)O(2) electrogeneration. The electrolyses have been performed using a small, undivided cell equipped with a Pt or thin film boron-doped diamond (BDD) anode and a carbon-felt cathode. The higher performance of the EF process with 0.2mM Fe(2+) in a BDD/carbon felt cell is demonstrated. This is due to the higher production of ()OH radicals, as well as to the simultaneous degradation at the anode surface and in the bulk solution. At low current, the oxidation at the anode was predominant; at high current, SMX was pre-eminently degraded in the bulk. SMX was quickly destroyed under all the conditions tested, following pseudo first-order kinetics; however, the almost total removal of the total organic carbon was only achieved in the BDD/carbon felt cell. The reaction by-products were quantified by chromatographic techniques and thus, the reaction pathway for the mineralization of SMX by EF has been elucidated. Hydroxylation of SMX on the sulfanilic ring is suggested as the first step, followed by the formation of p-benzoquinone and 3-amino-5-methylisoxazole. Their oxidative cleavage led to the formation of five carboxylic acids that were finally mineralized to CO(2); the release of NH(4)(+), NO(3)(-), and SO(4)(2-) accounted for almost 100% of the initial nitrogen and sulfur content. The absolute rate constants for the oxidative degradation of SMX and the detected aromatic by-products have also been determined.
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The removal of sulfadiazine, sulfamethizole, sulfamethoxazole, and sulfathiazole from aqueous solution by ozonation was studied. The study was conducted experimentally in a semi-batch reactor under different experimental conditions, i.e., varying influent ozone gas concentration, bicarbonate ion concentration, and pH. The results of the study indicated that ozonation could be used to effectively remove the sulfonamides from water. The sulfonamides exhibited moderate reactivity towards aqueous ozone, k(O)(3) >2 x 10(4) M(-1)s(-1) at pH of 2 and 22 degrees C. The mol of ozone absorbed by the solution per mol of sulfonamides removed varied in the range of 5.5-12.0 with lower ranges representing ozone absorption by the solution at the beginning of the ozonation process whereas higher ratios correspond to >99.9% removal of the target sulfonamides. The removal rate of the sulfonamides improved with bicarbonate ion concentration up to 8mM but further increase in bicarbonate ion decreased removal efficiency. It was also observed that increasing the pH from 2.0 to 10.0 resulted in enhanced removal of the sulfonamides.
Ibuprofen (IBP) is a widely used analgesic and anti-inflammatory drug and has been found as a pollutant in aqueous environments. The sonolytic, photocatalytic and sonophotocatalytic degradations of IBP in the presence of homogeneous (Fe(3+)) and heterogeneous photocatalysts (TiO(2)) were studied. When compared with sonolysis and photocatalysis, a higher degradation rate was observed for sonophotocatalysis in the presence of TiO(2) or Fe(3+) and also a slight synergistic enhancement was found with a synergy index of 1.3 and 1.6, respectively. Even though TiO(2) sonophotocatalysis showed an additive process effect in the mineralization, a significant synergy effect was observed for the sonophotocatalysis in the presence of Fe(3+). This might be due to the formation of photoactive complexes between Fe(3+) and IBP degradation products, such as carboxylic acids. High performance liquid chromatography (HPLC) and electrospray ionisation mass spectrometry (ESMS) techniques were employed for the identification of the degradation intermediates. The sonication of IBP led to the formation of its mono- and di-hydroxylated intermediates. Apart from the hydroxylated intermediates, products formed due to the oxidation of propanoic acid and isobutyl substituents of IBP were also observed.
This work focuses on the treatment of real effluents from a municipal wastewater treatment plant (RE) with solar photo-Fenton (5 mg and 20 mg L(-1) Fe, pH approximately 3 and 50 mg L(-1) initial H(2)O(2) concentration) at pilot plant scale. In some experiments RE was spiked with 15 different (acetaminophen, antipyrine, atrazine, caffeine, carbamazepine, diclofenac, flumequine, hydroxybiphenyl, ibuprofen, isoproturon, ketorolac, ofloxacin, progesterone, sulfamethoxazole, and triclosan) emerging contaminants (ECs) at 100 and 5 microg L(-1) each which were added directly into RE prior to treatment. All experiments showed successful degradation of ECs in real effluents from different municipal wastewater treatment plants at low iron concentration (5 mg L(-1)). Although the most degradation took place during the Fenton process, photo-Fenton was necessary to degrade all ECs below their limit of detection (LOD). In the case of the RE containing 52 ECs (determined by HPLC-QTRAP-MS), four of them could not be degraded to their LOD and were still present, although at extremely low concentrations (nicotine 47 ng L(-1), cotinine 11 ng L(-1), chlorfenvinphos 99 ng L(-1), and caffeine 8 ng L(-1)). ECs were easily degraded by (*)OH without substantial competition with the organic content of the RE.
In this study the degradation of the worldwide Non-Steroidal Anti-Inflammatory Drug (NSAID) ibuprofen (IBP) by photo-Fenton reaction by use of solar artificial irradiation was carried out. Non-photocatalytic experiments (complex formation, photolysis and UV/Vis-H(2)O(2) oxidation) were executed to evaluate the isolated effects and additional differentiated degradation pathways of IBP. The solar photolysis cleavage of H(2)O(2) generates hydroxylated-IBP byproducts without mineralization. Fenton reaction, however promotes hydroxylation with a 10% contamination in form of a mineralization. In contrast photo-Fenton in addition promotes the decarboxylation of IBP and its total depletion is observed. In absence of H(2)O(2) a decrease of IBP was observed in the Fe(II)/UV-Vis process due to the complex formation between iron and the IBP-carboxylic moiety. The degradation pathway can be described as an interconnected and successive principal decarboxylation and hydroxylation steps. TOC depletion of 40% was observed in photo-Fenton degradation. The iron-IBP binding was the key-point of the decarboxylation pathway. Both decarboxylation and hydroxylation mechanisms, as individual or parallel process are responsible for IBP removal in Fenton and photo-Fenton systems. An increase in the biodegradability of the final effluent after photo-Fenton treatment was observed. Final BOD(5) of 25 mg L(-1) was reached in contrast to the initial BOD(5) shown by the untreated IBP solution (BOD(5)<1 mg L(-1)). The increase in the biodegradability of the photo-Fenton degradation byproducts opens the possibility for a complete remediation with a final post-biological treatment.
The study examined the effect of operating conditions of the Fenton process on biodegradability improvement and mineralization of amoxicillin, ampicillin and cloxacillin antibiotics in aqueous solution. In addition, degradation of amoxicillin, ampicillin and cloxacillin under optimum operating conditions were evaluated. The optimum operating conditions for an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin, and cloxacillin, respectively were observed to be COD/H2O2/Fe2+ molar ratio 1:3:0.30 and pH 3. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and cloxacillin occurred in 2 min. In addition, biodegradability improved from approximately 0 to 0.37 in 10 min, and COD and DOC degradation were 81.4% and 54.3%, respectively in 60 min. Maximum biodegradability (BOD5/COD ratio) improvement was achieved in 10, 20 and 40 min at antibiotics concentration 100, 250 and 500 mg/L, respectively for each antibiotic in aqueous solution. Increase in nitrate and ammonia concentration were observed due to mineralization of organic nitrogen, concentration of nitrate increased from 0.3 to 10 mg/L and concentration of ammonia increased from 8 to 13 mg/L in 60 min. The study indicated that Fenton process can be used for pretreatment of amoxicillin, ampicillin and cloxacillin wastewater for biological treatment.
In this work, the photocatalytic degradation of the antibiotic sulfamethoxazole (SMX) by solar photo-Fenton at pilot plant scale was evaluated in distilled water (DW) and in seawater (SW). Degradation and mineralization of SMX were strongly hindered in SW compared to DW. The influence of H(2)O(2) and iron concentration on the efficiency of the photocatalytic process was evaluated. An increase in iron concentration from 2.6 to 10.4 mg L(-1) showed only a slight improvement in SMX degradation and mineralization. However, an increase in H(2)O(2) concentration up to 120 mg L(-1) during photo-Fenton in DW decreased SMX solution toxicity from 85% to 20%, according to results of Daphnia magna bioassays. The same behaviour was not observed after photo-Fenton treatment in SW. Despite 45% mineralization in SW, toxicity increased from 16% to 86% as shown by Vibrio fischeri bioassays, which suggests that the intermediates generated in SW are different from those in DW. A SMX degradation pathway during the photo-Fenton treatment in DW is proposed.
Although antibiotics have been used in large quantities for some decades, until recently the existence of these substances in the environment has received little notice. It is only in recent years that a more complex investigation of antibiotic substances has been undertaken in order to permit an assessment of the environmental risks they may pose. Within the last decade an increasing number of studies covering antibiotic input, occurrence, fate and effects have been published, but there is still a lack of understanding and knowledge about antibiotics in the aquatic environment despite the numerous studies performed. This review addresses the present state of knowledge concerning the input, occurrence, fate and effects of antibiotics in the environment. It brings up important questions that are still open, and addresses some significant issues which must be tackled in the future for a better understanding of the behavior of antibiotics in the environment, as well as the risks associated with their occurrence. Questions related to resistance in the environment that may be caused by antibiotics will be addressed in the second part.
Although antibiotics have been used in large quantities for some decades, until recently the existence of these substances in the environment has received little notice. It is only in recent years that a more complex investigation of antibiotic substances has been undertaken in order to permit an assessment of the environmental risks they may pose. Within the last decade, an increasing number of studies covering antibiotic input, occurrence, fate and effects have been published. Antibiotics are one of the most important groups of pharmaceuticals. Antibiotic resistance is one of the major challenges for human medicine and veterinary medicine. However, there is still a lack of understanding and knowledge about sources, presence and significance of resistance of bacteria against antibiotics in the aquatic environment despite the numerous studies performed. This review summarizes this topic. It names important open questions and addresses some significant issues which must be tackled in the future for a better understanding of resistance related to antibiotics in the environment.
The application of ultrasound (US) waves for remediation of wastewater is an area of increasing interest and promising results. The aim of this paper is to evaluate the influence of several parameters of the US process on the degradation of ibuprofen (IBP), a widely used non-steroidal anti-inflammatory recalcitrant drug found in water. Applied US power, dissolved gas, pH and initial concentration of IBP were the parameters investigated under sonication (300 kHz). Ultrasound increased the degradation of IBP from 30 to 98% in 30 min. Initial rate of IBP degradation was evaluated in the range of 1.35 and 6.1 micromolL(-1)min(-1) for initial concentrations of 2 to 21 mgL(-1) or 9.7 micromolL(-1) to 101 micromolL(-1), respectively. Under air and oxygen the degradation rate of IBP was 4 micromolL(-1)min(-1) being higher than that when argon was used. The most favorable degradation pH was acidic media. Complete removal of IBP was achieved but some dissolved organic carbon (DOC) remained in solution showing that long-lived intermediates were recalcitrant to the US irradiation. However, chemical and biological oxygen demands (COD and BOD(5)) indicated that the process oxidize the ibuprofen compound to biodegradable substances removable in a subsequent biological step.
In this study, water containing the pharmaceutical compound sulfamethoxazole (SMT) was subjected to the various treatments of different oxidation processes involving ozonation, and photolysis and catalysis under different experimental conditions. Removal rates of SMT and total organic carbon (TOC), from experiments of simple UVA radiation, ozonation (O(3)), catalytic ozonation (O(3)/TiO(2)), ozone photolysis (O(3)/UVA), photocatalytic oxidation (O(2)/TiO(2)/UVA) and photocatalytic ozonation (O(3)/UVA/TiO(2)), have been compared. Photocatalytic ozonation leads to the highest SMT removal rate (pH 7 in buffered systems, complete removal is achieved in less than 5min) and total organic carbon (in unbuffered systems, with initial pH=4, 93% TOC removal is reached). Also, lowest ozone consumption per TOC removed and toxicity was achieved with the O(3)/UVA/TiO(2) process. Direct ozone and free radical reactions were found to be the principal mechanisms for SMT and TOC removal, respectively. In photocatalytic ozonation, with buffered (pH 7) aqueous solutions phosphates (buffering salts) and accumulation of bicarbonate scavengers inhibit the reactions completely on the TiO(2) surface. As a consequence, TOC removal diminishes. In all cases, hydrogen peroxide plays a key role in TOC mineralization. According to the results obtained in this work the use of photocatalytic ozonation is recommended to achieve a high mineralization degree of water containing SMT type compounds.
Pharmaceuticals and other micropollutants in wastewater pose a new challenge to wastewater professionals as well as to the pharmaceutical industry. Although there is a great deal of uncertainty concerning the possible detrimental effects on the aquatic ecosystems, the precautionary principle--or possibly new scientific evidence--may give rise to more stringent demands on wastewater treatment in the future. In conventional wastewater treatment plants, a combination of biological treatment with high sludge residence times and ozonation of the effluent seems to be the most promising technology. Ozonation, however, is an energy-intensive technology. Moreover, in conventional end-of-pipe systems a large part of the pollutants will always be lost to the environment due to leaking, primarily during rain. In the long term, source separation offers the more sustainable solution to the entire wastewater problem, including organic micropollutants. Urine source separation is an elegant solution to the problems of nutrients and pharmaceuticals alike and losses of untreated pollutants to the environment can be minimized. Although few technologies for the separate treatment of urine have been developed to date, the 100-500 times higher concentrations of micropollutants promise more efficient conditions for all removal technologies known from conventional wastewater treatment.
To reduce the release of pharmaceuticals and endocrine disruptors into the aquatic environment or to remove them from wastewater intended for direct or indirect reuse, the application of advanced wastewater treatment may be required. In the present study, municipal wastewater effluents were treated with ozone (O3) in a pilot-scale plant consisting of two bubble columns. The investigated effluents, which varied in suspended solids concentrations, comprised an effluent of conventional activated sludge treatment (CAS), the same effluent dosed with 15 mg of TSS L(-1) of activated sludge (CAS + SS), and the effluent of a membrane bioreactor pilot plant (MBR). Selected classes of pharmaceuticals were spiked in the wastewater at realistic levels ranging from 0.5 to 5 microg L(-1). Samples taken at the inlet and the outlet of the pilot plant were analyzed with liquid chromatography (LC)-electrospray tandem mass spectrometry (MS). Macrolide and sulfonamide antibiotics, estrogens, and the acidic pharmaceuticals diclofenac, naproxen, and indomethacin were oxidized by more than 90-99% for O3 doses > or = 2 mg L(-1) in all effluents. X-ray contrast media and a few acidic pharmaceuticals were only partly oxidized, but no significant differences were observed among the three effluents. These results show that many pharmaceuticals present in wastewater can be efficiently oxidized with O3 and that suspended solids have only a minor influence on the oxidation efficiency of nonsorbing micropollutants.
The potential occurrence of endocrine-disrupting compounds (EDCs) as well as pharmaceuticals and personal care products (PPCPs) in drinking water supplies raises concern over the removal of these compounds by common drinking water treatment processes. Three drinking water supplies were spiked with 10 to 250 ng/L of 62 different EDC/ PPCPs; one model water containing an NOM isolate was spiked with 49 different EDC/PPCPs. Compounds were detected by LC/MS/MS or GC/MS/MS. These test waters were subjected to bench-scale experimentation to simulate individual treatment processes in a water treatment plant (WTP). Aluminum sulfate and ferric chloride coagulants or chemical lime softening removed some polyaromatic hydrocarbons (PAHs) but removed <25% of most other EDC/ PPCPs. Addition of 5 mg/L of powder activated carbon (PAC) with a 4-h contact time removed 50% to >98% of GC/ MS/MS compounds (more volatile) and 10% to >95% of LC/ MS/MS compounds (more polar); higher PAC dosages improved EDC/PPCP removal. EDC/PPCP percentage removal was independent of the initial compound concentration. Octanol-water partition coefficients served as a reasonable indicator of compound removal under controlled PAC test conditions, except for EDC/PPCPs that were protonated or deprotonated at the test pH and some that contained heterocyclic or aromatic nitrogen. Separate chlorine or ozone experiments decreased the EDC/PPCP initial concentration by <10% to >90%; EDC/PPCPs were likely transformed to oxidation byproducts. Ozone oxidized steroids containing phenolic moieties (estradiol, ethynylestradiol, or estrone) more efficiently than those without aromatic or phenolic moieties (androstenedione, progesterone, and testosterone). EDC/PPCP reactivity with oxidants were separated into three general groups: (1) compounds easily oxidized (>80% reacted) by chlorine are always oxidized at least as efficiently by ozone; (2) 6 of the -60 compounds (TCEP, BHC, chlordane, dieldrin, heptachlor epoxide, musk ketone) were poorly oxidized (<20% reacted) by chlorine or ozone; (3) compounds (24 of 60) reacting preferentially (higher removals) with ozone rather than chlorine. Conventional treatment (coagulation plus chlorination) would have low removal of many EDC/PPCPs, while addition of PAC and/or ozone could substantially improve their removals. Existing strategies that predict relative removals of herbicides, pesticides, and other organic pollutants by activated carbon or oxidation can be directly applied for the removal of many EDC/PPCPs, but these strategies need to be modified to account for charged (protonated bases or deprotonated acids) and aliphatic species. Some compounds (e.g., DEET, ibuprofen, gemfibrozil) had low removals unless ozonation was used. Other compounds had low removals by all the WTP processes considered (atrazine, iopromide, meprobamate, TCEP), and removal processes capable of removing these types of compounds should be investigated.
A pilot plant for ozonation and UV-disinfection received effluent from a German municipal sewage treatment plant (STP) to test the removal of pharmaceuticals, iodinated X-ray contrast media (ICM) and musk fragrances from municipal wastewater. In the original STP effluent, 5 antibiotics (0.34-0.63 microgl(-1)), 5 betablockers (0.18-1.7 microgl(-1)), 4 antiphlogistics (0.10-1.3 microgl(-1)), 2 lipid regulator metabolites (0.12-0.13 microgl(-1)), the antiepileptic drug carbamazepine (2.1 microgl(-1)), 4 ICM (1.1-5.2 microgl(-1)), the natural estrogen estrone (0.015 microgl(-1)) and 2 musk fragrances (0.1-0.73 microgl(-1)) were detected by LC-electrospray tandem MS and/or GC/MS/MS. ICM, derived from radiological examinations, were present with the highest concentrations (diatrizoate: 5.7 microgl(-1), iopromide: 5.2 microgl(-1)). By applying 10-15 mgl(-1) ozone (contact time: 18 min), all the pharmaceuticals investigated as well as musk fragrances (HHCB, AHTN) and estrone were no longer detected. However, ICM (diatrizoate, iopamidol, iopromide and iomeprol) were still detected in appreciable concentrations. Even with a 15 mgl(-1) ozone dose, the ionic diatrizoate only exhibited removal efficiencies of not higher than 14%, while the non-ionic ICM were removed to a degree of higher than 80%. Advanced oxidation processes (O(3)/UV-low pressure mercury arc, O(3)/H(2)O(2)), which were non-optimized for wastewater treatment, did not lead significantly to a higher removal efficiency for the ICM than ozone alone.
Ozone and hydroxyl radical (*OH) reaction kinetics were measured for 14 antibacterial compounds from nine structural families, to determine whether municipal wastewater ozonation is likely to result in selective oxidation of these compounds' biochemically essential moieties. Each substrate is oxidized by ozone with an apparent second-order rate constant, k''(O3,app) > 1 x 10(3) M(-1) s(-1), at pH 7, with the exception of N(4)-acetylsulfamethoxazole (K''(O3,app) is 2.5 x 102 M(-1) s(-1)). k''(O3,app) values (pH 7) for macrolides, sulfamethoxazole, trimethoprim, tetracycline, vancomycin, and amikacin appear to correspond directly to oxidation of biochemically essential moieties. Initial reactions of ozone with N(4)-acetylsulfamethoxazole, fluoroquinolones, lincomycin, and beta-lactams do not lead to appreciable oxidation of biochemically essential moieties. However, ozone oxidizes these moieties within fluoroquinolones and lincomycin via slower reactions. Measured k''(O3,app) values and second-order *OH rate constants, k''(*OH,app) were utilized to characterize pollutant losses during ozonation of secondary municipal wastewater effluent. These losses were dependent on k''(O3,app), but independent of k''(*OH,app). Ozone doses > or =3 mg/L yielded > or =99% depletion of fast-reacting substrates (K''(O3,app) > 5 x 10(4) M(-1) s(-1)) at pH 7.7. Ten substrates reacted predominantly with ozone; only four were oxidized predominantly by .OH. These results indicate that many antibacterial compounds will be oxidized in wastewater via moiety-specific reactions with ozone.
Liquid chromatography/tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) was used to measure the concentrations of 14 pharmaceuticals, 6 hormones, 2 antibiotics, 3 personal care products (PCPs), and 1 flame retardant in surface waters and wastewater treatment plant effluents in South Korea. Tris (2-chloroethyl) phosphate (TCEP), iopromide, naproxen, carbamazepine, and caffeine were quite frequently observed (>80%) in both surface waters and effluents. The analytes of greatest concentration were iopromide, TCEP, sulfamethoxazole, and carbamazepine. However, the primary estrogen hormones, 17alpha-ethynylestradiol and 17beta-estradiol, were rarely detected, while estrone was detected in both surface water and wastewater effluent. The elimination of these chemicals during drinking water and wastewater treatment processes at full- and pilot-scale also was investigated. Conventional drinking water treatment methods were relatively inefficient for contaminant removal, while efficient removal (approximately equal to 99%) was achieved by granular activated carbon (GAC). In wastewater treatment processes, membrane bioreactors (MBR) showed limited target compound removal, but were effective at eliminating hormones and some pharmaceuticals (e.g., acetaminophen, ibuprofen, and caffeine). Membrane filtration processes using reverse osmosis (RO) and nanofiltration (NF) showed excellent removal (>95%) for all target analytes.
Sulfamethoxazole (SMX) is a bacteriostatic antibiotic largely used for diverse types of illness. Its widely use in humans and even in animals releases unmetabolized and active metabolites that have a strong potential in terms of effect in organisms. In this work, 200 mg L(-1) solution of sulfamethoxazole was treated by ozonation at different pH. Results showed that ozonation was proved to be an efficient method to degrade sulfamethoxazole. After 15 min of ozonation (corresponding dose=0.4 g of ozone L(-1)), the complete antibiotic abatement was almost achieved with just 10% of mineralization. The biodegradability and toxicity of the ozonation intermediates were also studied. A biodegradability enhancement (increment of BOD(5)/COD ratio) from 0 to 0.28 was observed after 60 min of ozonation. The acute toxicity of the intermediates was followed by the Microtox test and the toxicity profile showed a slight acute toxicity increment in the first stage of ozonation. The pH variation had an important role in the TOC and COD removal, promoting their growth with the increment of alkalinity. The second order kinetic constants for the ozonation of the SMX in an order of magnitude of 10(5) L mol(-1)s(-1) were also determined for pH 5 and 7.
The kinetics of Ultraviolet C (UV-C)-induced direct phototransformation of four representative pharmaceuticals, i.e., 17alpha-ethinylestradiol (EE2), diclofenac, sulfamethoxazole, and iopromide, was investigated in dilute solutions of pure water buffered at various pH values using a low-pressure and a medium-pressure mercury arc lamp. Except for iopromide, pH-dependent rate constants were observed, which could be related to acid-base equilibria. Quantum yields for direct phototransformation were found to be largely wavelength-independent, except for EE2. This compound, which also had a rather inefficient direct phototransformation, mainly underwent indirect phototransformation in natural water samples, while the UV-induced depletion of the other pharmaceuticals appeared to be unaffected by the presence of natural water components. At the UV-C (254 nm) drinking-water disinfection fluence (dose) of 400 Jm(-2), the degree of depletion of the select pharmaceuticals at pH=7.0 in pure water was 0.4% for EE2, 27% for diclofenac, 15% for sulfamethoxazole, and 15% for iopromide, indicating that phototransformation should be seriously taken into account when evaluating the possibility of formation of UV transformation products from pharmaceuticals present as micropollutants.