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Semi continuous flow experiments for fluoride removal were undertaken to investigate the effects of the different parameters such as: applied voltage (10–20 V), flow rate (150–450 ml/min), initial pH (6–8), and initial fluoride concentration (2–10 mg/l) at lowest cost with novel rector. The maximum of 8 mg/l fluoride treated up to world health orga...
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En este trabajo se evalúo el proceso de electrocoagulación (EC) en un prototipo para remoción de arsénico y flúor en agua de pozo, con el objetivo de atender la problemática actual del agua para consumo humano contenida en el acuífero del Valle de Guadiana, ubicado en el municipio de Durango, que históricamente ha presentado concentraciones de flúo...
In this study, surface response methodology was employed to investigate the effect of different interacting factors on the removal of fluoride from synthetic water using aluminum electrocoagulation (Al-EC) and iron electrocoagulation (Fe-EC) in different reactors. Box-Behnken design of a Design Expert version 11 was used for the optimization and ev...
This experimental study concerns the elimination of fluoride from water using an electrocoagulation reactor having a variable flow direction in favour of increasing the electrolysing time, saving the reactor area, and water mixing. The detention time of the space-saver EC reactor (S-SECR) was measured and compared to the traditional reactors using...
The presence of excessive amounts of fluoride than prescribed standards has been reported in various sources of domestic water supply around the slopes of Mount Meru and other parts in Tanzania. Efforts to remove the excessive fluoride have been carried out using various technologies. In this study, electrocoagulation experiments were carried out t...
Fluoride ions present in drinking water are beneficial to human health when at proper concentration levels (0.5-1.5 mg L −1), but an excess intake of fluoride (>1.5 mg L −1) may pose several health problems. In this context, reducing high fluoride concentrations in water is a major worldwide challenge. The World Health Organization has recommended...
Citations
... In order to increase the oxidation reactions, voltage shall be adjusted according to the degradation efficiency. Along with voltage, electrode material selection also alters the degradation efficiency [20][21][22]. Based on the electrical conductivity, electrolyte can be added to enhance the conductivity of the leachate [22]. ...
Chemical, Material Sciences & Nano technology book series aims to bring together leading academic scientists, researchers and research scholars to exchange and share their experiences and research results on all aspects of Chemical, Material Sciences & Nano technology. The field of advanced and applied Chemical, Material Sciences & Nano technology has not only helped the development in various fields in Science and Technology but also contributes the improvement of the quality of human life to a great extent. The focus of the book would be on state-of-the-art technologies and advances in Chemical, Material Sciences & Nano technology and to provides a remarkable opportunity for the academic, research and industrial communities to address new challenges and share solutions.
... At lower fluoride concentration of 5 mg/L and pH 3, the removal of fluoride was higher and didn't affect much till the neutral pH 7. However, the removal was decreased with an increase in the concentration of fluoride solution because of increase in the fluoride ions with respect to the available coagulant complexes (Bhagawan et al. 2019). ...
The main objective of this study was to assess the continuous electrocoagulation process effectiveness for removing fluoride from potable water. The effect of different parameters like applied potential, electrode spacing, and feed flow rate was optimized for the continuous removal of fluoride from potable water. Response surface methodology (RSM) was used to examine the impact on essential operational factors such as voltage, concentration, and pH for fluoride removal as a response. The results demonstrate that all the parameters had a significant effect on removal efficiency. The quadratic model accurately predicted the optimal parameters for maximal fluoride removal efficiency with the association of desirability 1.0, which was discovered to be voltage 2.38 V, feed concentration 5.52 mg/L, and pH 6.45. According to the analysis of variance, R2 of the proposed quadratic model is higher (0.9877). Moreover, the difference between the predicted R2 of 0.9258 and the adjusted R2 of 0.9767 was less than 0.2. The model adequacy was also studied based on residual plot, perturbation plot, and box-cox plot. The RSM was best modeling techniques use to predict data than the multilayer perceptron and linear regression due to high accuracy. Finally, the generated flocs were characterized by scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction, and Fourier transform infrared spectroscopy instrumental techniques. The outcomes demonstrate that a newly designed continuous electrocoagulation process is a promising alternative for the removal of fluoride from potable water.
... The basic economic evaluation carried out by Mena et al. [271] resulted that the associated price of fluoride removal using EC is 0.27 $/m 3 . Additionally, Bhagawan et al. [272] reported that the operation cost of EC in fluoride removal range between 0.28 and 0.98 $/m 3 . The cost of EC process mostly depends on electrode materials, electricity consumed and fluoride initial concentration. ...
Fluoride has a significant impact on our surroundings. Various treatment methodologies are available to reduce the fluoride level in groundwater and surface water. Water containing fluoride is most likely to affect humans, plants, and animals in different ways, based on the allowable limits set by the countries. This way, an attempt has been made to review the different parameters related to fluoride occurrence, effect, and treatment. The aim of this work is to review the literature about the background of fluoride availability, the source of fluoride, highlight the potential effect of fluoride on the surrounding, and compile different treatment techniques for fluoride removal. This review will be helpful to the research scholars who work in the field of water and wastewater treatment from groundwater and surface water.
... In this relevance, along with the aqueous phase recognition of F -, development of environmentally sustainable Fremoval strategies is an obvious mandate in today's scientific world (Ghosh and Banerjee 2019;Gao et al. 2014;Mondal et al. 2021;Mukhopadhyay et al. 2020). A series of methodologies, for instance, adsorption, precipitation, coagulation, ion exchange, and membrane-based methods, have been postulated in literature aiming this (Aigbe and Osibote 2022;Bhagawan et al. 2019;Jadhao et al. 2019;Karthika et al. 2018;Krishnan et al. 2017;Li et al. 2010;Lyu et al. 2016;Mahadevan et al. 2018;Majumder 2019;Malalagama et al. 2022;Melidis 2015;Mondal and George 2015). The adsorption technology is considered the most proficient, economically viable, and widely implemented methodolgy amidst these, owing to minimal energy consumption and less wearisome processing methodology. ...
An inimitable adsorbent “FI-TM-BWCC,” emanated from meta-phase-selective thermochemical modulation of excavation-squander (mine waste)-derived terra-firma (blackish white china clay, i.e., BWCC), is explored in the present work for fluoride (F⁻) adsorption purpose. FI-TM-BWCC portrayed an excellent adsorption efficiency (95% removal capacity and Qe: 99 mg/g, at initial adsorbate dose: 10 mg/L, pH: 7±0.5, adsorbent dosage: ~600 mg, exposure time: 60 min). At identical experimental conditions, the F⁻ scavenging phenomenon was superior than two analogous adsorbents: (i) biopolymer chitosan and glutaraldehyde cross-linked BWCC (CG@BWCC, wherein F⁻ removal efficiency: 74%) and (ii) meta-phase-selective thermally moduled BWCC (TM-BWCC, removal efficiency: 75%). BWCC predominantly comprises kaolinite and a trace amount of anatase along with prime elemental compositions: 41.71% Al2O3, 49.80 % SiO2, 4.25% Fe2O3, and 3.93% TiO2, as revealed by PXRD and XRF analyses. The thermochemical modulation pathway significantly escalated the BET surface area of BWCC (~11.92 m²/g, avg. pore radius: 23.64 Å, i.e., mesoporous in nature) to FI-TM-BWCC (216.95 m²/g, avg. pore radius: 31.41 Å). The fluoride-adsorbed F⁻•••FI-TM-BWCC species revealed a reduced surface area of 21.5 m²/g, which was explained in the light of ion exchange pathway on FI-TM-BWCC’s non-uniform surface (surface roughness/SA of 1597 nm, reduced to 1179 nm after F⁻ uptake). The spontaneous F⁻•••FI-TM-BWCC interaction (ΔG⁰ = −6.25 kJ) occurred following chemisorption-controlled ion exchange (CCIE) pathway as appearance of a F1s band at 685.5 eV was rationalized for Si-F bond formation; corroborating pseudo second-order (PSO) kinetics and resembling Freundlich isotherm. The usefulness of FI-TM-BWCC was diversified through field validation with natural groundwater specimens and proposition of a gravity-fed defluoridation unit. The flow rate was documented to be ~11 liters per hour (LPH) by implementing viscous turbulence fluent model. The experimental findings certainly followed the premise conventions of sustainability metrics upholding socio-economic equipoise.
Graphical abstract
... Pesticide intermediate industrial wastewater sample has been collected from pesticide intermediates industry located at Hyderabad, Telangana, India. Physicochemical characterisation of wastewater samples has been carried out using "standard methods for the examination of water and wastewater 21st addition-2005, APHA" (Jotin R et al. 2012;Bhagawan et al. 2019). Initial characterisation of the sample has been provided in Table 1. ...
Now-a-days industrial wastewater treatment has been a major preventive step against the pollution of natural water resources. This wastewater contains different type of contaminants and it needs prior treatment for its discharge in to water body. This study deals with the treatment of pesticide intermediate industrial wastewaters using individual treatment processes such as fenton, photo-fenton, electro-oxidation, rotavapor distillation, and coagulation. Optimization of operational parameters such as reaction time and fenton reagent dosages in fenton process, coagulant dosage in coagulation, inter-electrode distance, reaction time and pH in electro-oxidation process had been carried out in this study for the optimal reduction of chemical oxygen demand (COD). Using optimised dosages of fenton reagents FeSO4.7H2O of 0.1 g/l, H2O2 of 1.75 g/l for 250 ml of sample (i.e. Fe⁺²/H2O2 = 0.050) in the fenton treatment of pesticide intermediate industrial wastewater an optimum COD. Removal of 51.1% was obtained at a reaction time of 180 min and at a pH of 3. Where as in photo-fenton process, an optimum COD removal of 53.33% was obtained at a reaction time of 180 min. Using rotavapor distillation, highest percentage removal of COD (62.22%) was obtained at a distillation temperature of 100 ℃.
Graphic abstract
... Groundwater contains anions such as chloride (Cl − ), nitrate (NO 3 ; 0, 10, and 100 mg/L) to the bulk fluoride solution (C 0 = 10 mg/L and adsorbent dose = 1 g/L). The concentration range was selected based on actual chemical composition of groundwater contaminated with fluoride (Narsimha and Sudarshan, 2017;Bhagawan et al., 2019;Thakur and Mondar, 2017). In case of phosphate, 100 mg/L is not a relevant concentration. ...
The presence of excess fluoride (F⁻ > 1.5 mg/L) in drinking water affects more than 260 million people globally and leads to dental and skeletal fluorosis among other health problems. This study investigated fluoride removal by graphene oxide-ceria nanohybrid (GO-CeO2) and elucidated the mechanisms involved. The nanohybrid exhibited ultra-rapid kinetics for fluoride removal and the equilibrium (85% removal, 10 mg F⁻/L initial concentration) was achieved within 1 min which is one of the fastest kinetics for fluoride removal reported so far. Fluoride removal by the nanohybrid followed Langmuir isotherm with a maximum adsorption capacity of 8.61 mg/g at pH 6.5 and that increased to 16.07 mg/g when the pH was lowered to 4.0. Based on the experimental results and characterization data, we have postulated that both electrostatic interaction and surface complexation participated in the fluoride removal process. The O²⁻ ions present in the CeO2 lattice were replaced by F⁻ ions to make a coordination compound (complex). While both Ce⁴⁺ and Ce³⁺ were present in ceria nanoparticles (CeO2 NPs), Ce³⁺ participated in fluoride complexation. During fluoride removal by GO-CeO2, the GO sheets acted as electron mediators and help reduce Ce⁴⁺ to Ce³⁺ at the CeO2 NPs-GO interface, and the additional Ce³⁺ enhanced fluoride removal by the nanohybrid.
... The costs to defluoridate water by EC have been estimated in the recent scientific literature. Bhagawan et al. [94] concluded that the total cost could range from 0.28 to 0.98 $ m −3 of treated water. Besides, the type of sacrificial electrode and electrode configuration can affect the cost of EC. ...
... Bhagawan et al. [94] examined a lab-scale cylindrical reactor with a working volume of 2.5 L operating under semi-continuous flow-EC using aluminum and iron electrodes and stainless steel as anodes and cathodes, respectively. The application of the novel semicontinuous flow EC reactor demonstrated that the fluoride concentration of 8 mg L −1 in groundwater met the WHO drinking limits under conditions of 30 min, 300 mL min −1 flow rate, 15 V applied voltage, and pH 7. López-Guzmán et al. [10] investigated the EC lab-scale reactor for well water treatment containing 4.18 mg L −1 fluoride from the Guadiana Valley, Mexico. ...
Fluoride ions present in drinking water are beneficial to human health when at proper concentration levels (0.5-1.5 mg L −1), but an excess intake of fluoride (>1.5 mg L −1) may pose several health problems. In this context, reducing high fluoride concentrations in water is a major worldwide challenge. The World Health Organization has recommended setting a permissible limit of 1.5 mg L −1. The application of electrocoagulation (EC) processes has received widespread and increasing attention as a promising treatment technology and a competitive treatment for fluoride control. EC technology has been favourably applied due to its economic effectiveness, environmental versatility , amenability of automation, and low sludge production. This review provides more detailed information on fluoride removal from water by the EC process, including operating parameters, removal mechanisms, energy consumption, and operating costs. Additionally, it also focuses attention on future trends related to improve defluoridation efficiency.
... It is highly unlikely to have PO 4 3À and NO 3 À concentrations of 100 mg/L in groundwater and thus won't affect the F À removal efficiency. Additionally, the typical concentration of SO 4 2À in groundwater is 0.81e60 mg/L (Bhagawan et al., 2019;Sailo and Mahanta, 2014 (Amalraj and Pius, 2017). In addition, the degree of interference may also be related to the charge to radius ratio of the anions (PO 4 3À (3/3.40) ...
Excess fluoride (F⁻, >1.5 mg F⁻/L) in drinking water affects >260 million people across the globe and leads to dental and skeletal fluorosis. In this study, commercially available granular activated carbon (GAC) was modified with 0.3 M citric acid to get citric acid modified GAC (CAGAC). Over 70% of fluoride was removed in the first 60 min by CAGAC, whereas unmodified GAC removed only 30%. There were negligible interferences by co-existing ions (NO3⁻, Cl⁻, HCO3⁻, SO4²⁻, PO4³⁻) and organic matters. Maximum adsorption capacity of CAGAC was two times (1.65 mg/g) that of unmodified GAC (0.88 mg/g). Dubinin-Radushkevich (D-R) isotherm described the experimental data well indicating that ion exchange was involved in fluoride removal. CAGAC worked effectively over a wide range of pH (2–10) even though the point-of-zero-charge (PZC) was 4.89, and so the removal was not controlled by electrostatic interaction alone; surface adsorption and intra-particle diffusion were the rate-determining processes.
