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In this study, unmodified biosorbent was obtained from Arachis hypogea husk and applied to remove hexavalent chromium [Cr(VI)] from aqueous media through batch technique. The independent variables (contact time, pH of the solution and initial Cr(VI) concentration) influencing the adsorption process were optimized by central composite design (CCD) f...
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... These parameters were treated as independent variables, with the degradation of methyl orange (MO) as the response variable. The Central Composite Design (CCD), a widely used variant of RSM, was employed to investigate the effects of these two factors on the response [47,48]. This was accomplished through a series of thirteen experimental sets. ...
This study introduces a novel Fe3O4@SiO2/Ag/AgCl/CdS nanocomposite, designed for the efficient photocatalytic degradation of methyl orange (MO), serving as a proxy for synthetic water pollutants under visible light. A combination of co-precipitation, sol-gel, and photodeposition techniques was used to synthesize the desired nanocomposite. Leveraging the response surface methodology (RSM), we optimized the degradation process, achieving an unprecedented near-complete degradation efficiency of 99% within 90 min. The nanocomposite, characterized by an average diameter of 25 nm and uniform size distribution, demonstrated significant photocatalytic activity and stability, maintaining effectiveness over multiple usage cycles. Notably, the incorporation of Ag/AgCl alongside CdS not only extends the light absorption range but also facilitates charge separation, enhancing photocatalytic performance. Additionally, mineralization was confirmed by measuring the Chemical Oxygen Demand (COD) values. This work not only presents a significant advancement in the field of photocatalyst for water purification but also introduces a scalable and effective approach for the development of next-generation photocatalysts. Our findings highlight the potential of magnetic nanocomposites in environmental remediation, offering a sustainable solution for the degradation of organic pollutants.
Graphical Abstract
... It is widely used in medium optimization since it establishes and quantifies correlations between various factors fast and with few trials. During the process optimization stage, the Central composite design (CCD) in RSM is especially helpful for fitting second-order quadratic polynomials [5]. Currently, the application of Bokashi fermentation using EMBs for starter Bokashi bran has never been reported. ...
Mushroom production as the largest solid-state fermentation industry globally. It draws attention to a significant economic and environmental challenge, specifically the storage and disposal of expired mushroom blocks (EMBs) remaining after harvest. Importance of ongoing biotechnological research focused on fungi utilizing various agro-industrial wastes to produce biofertilizer for industrial. The paper proposes using EMBs as a substrate for Bokashi fermentation as fertilizer, focusing on the development of starter Bokashi Bran. The study identifies and optimize bacterial and fungal growth in Bokashi Fermentation using ADA starter Bokashi bran sample from ADA Fresh Farm, Johor Bharu using Response Surface Methodology (RSM). Factors affecting growth both microbes were analysed: EMB content (2 g/ml to 10 g/ml) and fermentation durations (5 days to 9 days). The analysis analysed the highest bacterial and fungal growth in Starter Bokashi Bran using the Design Experts (DE) software Version 7.0 predicting maximum growth at 8 days and 4g/ml respectively. The quadratic model showed a good fit, with an R-squared value exceeding 0.80 and a confidence level surpassing 95%.The research demonstrated that EMBs can be utilized as alternative medium for starter bokashi bran that are eco-friendly and sustainable biofertilizer.
... In this regard, huge efforts have been directed to develop and find new approaches and techniques to solve this issue and minimize its negative impacts. Many methods have been employed to treat and eliminate heavy metals from water such as Precipitation, Coagulation and Flocculation, Ion Exchange, Membrane Filtration, Electrochemical Treatment, Biological Treatment, Chelation, and adsorption [14][15][16][17][18]. The adsorption technique is considered one of the most attractive means to treat pollutants due to its simplicity, efficiency, and versatile applicability [19,20]. ...
... This content may vary according to the origin and nature of weather and soil [25,26]. For instance, the content of cellulose differs (55-90)%; lignin ranges (10-23)%; and that of hemicellulose is (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)% approximately [27,28]. it is composed of abundant and very stable hydroxyl groups (-OH) that can be modified and good to support some other functional compounds [29]. Several studies have been done for the synthesis of LC-based composites and investigated their potential application in the removal of heavy metal ions such as Pb (II) [30,31], Mg, Zn and Ni [32], and Cu [33]. ...
Water treatment has emerged as a global priority in recent years due to its direct impact on human health. Toaddress this concern, the utilization of cost-effective, readily available, and efficient materials is imperative inovercoming associated challenges. In this study, cellulose derived from Luffa cylindrica (LC) underwent oxida-tion using (2,2,6,6-tetramethylpiperidine-1-yl)oxyl (TEMPO) and subsequently functionalized with amine groupsfrom poly(ethylenimine) (PEI). The resulting material was then composited with polyvinyl alcohol (PVA)nanofiber. The modified membrane was employed for the adsorption of hexavalent chromium from wastewaterusing various pH, contact time, temperature, concentration, and composite dose. The findings revealed that theprocess is pH-dependent with a high optimal removal (93 %) observed at pH 2, (94 %) for the composite dose,and (90.3 %) for contact time. The Kinetics were studied by applying pseudo-first-order, pseudo-second-order,Elovich, and Intraparticle diffusion models. And the data suggested that the adsorption process adheres to thepseudo-second-order model (R2 = 0.9948). Moreover, the adsorption isotherm examined by Langmuir,Freundlich, Tempkin, and D-P equation and results exhibited a satisfactory fit to the Langmuir isotherm (R2 =0.99193) and the maximum removable capacity was (52.91)
(PDF) Enhanced water treatment with TEMPO-modified luffa cellulose-PVA nanofiber composite for removal of hexavalent chromium. Available from: https://www.researchgate.net/publication/381468048_Enhanced_water_treatment_with_TEMPO-modified_luffa_cellulose-PVA_nanofiber_composite_for_removal_of_hexavalent_chromium [accessed Jun 16 2024].
... Nevertheless, many of these treatment techniques are ineffective and time-consuming [5,6]. For example, reverse osmosis can only be used to remove trace amounts of heavy metals and is considered not to be an efficient method for removing heavy metals from aquatic environments/industrial effluent [7]. ...
... The central composite design contains 2 k factorial runs, k c center runs, and 2 k axial runs, in which the total experimental runs (N) that could be conducted are calculated as Eq. (1) [6]. ...
... As represented in Table 5, the response of R 2 was 0.9971, which recommends that the analyzed process parameters can describe 99.71% of the response variability in adsorption capacity, and it could not describe nearly 0.29% of the response variation. It was obtained that the value of R 2 is very close to 1, showing the exact correlation between the experimental and predicted value, thus showing the adequacy of the model [6]. In another way, the determinant coefficients of R 2 and adjusted R 2 shown in Table 5 indicate the close agreement of experimental and predicted values. ...
The present study mainly focuses on the statistical analysis and optimization of Hg(II) removal from aqueous solution by wheat straw-supported magnetite nanoparticles (Fe3O4-WSS NPs). A response surface methodology with the central composite design was used to optimize the adsorption of Hg(II) and adsorption parameters. Following a central composite design (CCD) model, the result of the analysis revealed that the optimum adsorption parameters acquired by the quadratic model for maximum percentage removal of Hg(II) were 6.42, 40 mg/L, 1 g, and 35 min for pH, initial Hg(II) concentration, the dosage of wheat straw-supported magnetite nanoparticles, and contact time respectively. Under these conditions, the maximum removal efficiency of Hg(II) was found to be 98.60%. Langmuir isotherm model yielded the best fit to the experimental data with a maximum adsorption capacity of 112.40 mg/g. The results from the kinetic study also showed that the pseudo-second-order model well predicted the adsorption process. Moreover, the findings of the studies were predominantly fitted to a pseudo-second kinetic model, the Elovich kinetic model, and the Dubinin-Radushkevich isotherm model indicating that the rate-limiting step for the adsorption of Hg(II) ions onto Fe3O4-WSS NPs was of chemisorption processes. The results from thermodynamic parameters (∆Ho, ∆Go, ∆So) indicated that the removal process of Hg(II) ions was endothermic, spontaneous, and feasible. The study performed for the regeneration and reusability cycles showed wheat straw-supported magnetite nanoparticles can retain more than 86% of Hg(II) ions over the five cycles.
... This negative surface charge significantly aids in the adsorption of heavy metals by the biosorbent. Bulk density is a crucial parameter in the context of carbon removal through filtration (Bayuo et al., 2020b).The measured bulk density of E.feroxSC was found to be 0.515 g/cm 3 surpassing the lower limit of 0.25 g/cm 3 set by American Water Work Association for granular activated carbons (Atemkeng et al., 2020). ...
Heavy metal pollution is an enduring environmental challenge that calls for sustainable and eco-friendly solutions. One promising approach is to harness discarded plant biomass as a highly efficient environmental friendly adsorbents. In this context, a noteworthy study has spotlighted the employment of Euryale ferox Salisbury seed coat (E.feroxSC) for the exclusion of trivalent and hexavalent chromium ions. This study aims to transform discarded plant residue into a novel, environmentally friendly, and cost-effective alternative adsorbent, offering a compelling alternative to more expensive adsorption methods. By repurposing natural materials, we can contribute to mitigating heavy-metal pollution while promoting sustainable and economically viable solutions in environmental remediation. The effect of different parameters, i.e., chromium ions’ initial concentration (5–25 mg L⁻¹), solution pH (2–7), adsorbent dosage (0.2–2.4 g L⁻¹), contact time (20–240 min), and temperature (298–313 K), were investigated. E.feroxSC proved highly effective, achieving 96.5% removal of Cr(III) ions at pH 6 and 97.7% removal of Cr(VI) ions at pH 2, with a maximum biosorption capacity of 18.33 mg/g for Cr(III) and 13.64 mg/g for Cr(VI), making it a promising, eco-friendly adsorbent for tackling heavy-metal pollution. The adsorption process followed the pseudo-second-order kinetic model, aligning well with the Langmuir isotherm, exhibited favorable thermodynamics, and was characterized as feasible, spontaneous, and endothermic with physisorption mechanisms. The investigation revealed that E.feroxSC effectively adsorbed Cr(VI) which could be rejuvenated in a basic solution with minimal depletion in its adsorption capacity. Conversely, E.feroxSC’s adsorption of Cr(III) demanded rejuvenation in an acidic milieu, exhibiting comparatively less efficient restoration.
... Biosorption is a process where a biological entity produces a material that can accumulate the heavy metals in its cellular structure (Bayuo et al., 2020(Bayuo et al., , 2022a(Bayuo et al., , 2023aBayuo, 2021a). Biosorption is a rapid and reversible process in which the ions get bonded to the functional groups that are available on the surface of biomass like bio-char, marine alga, chitin, etc. (Bayuo et al. 2021, b;Pandiyarajan et al. 2023). ...
... The kinetic investigation's findings reveal the sorption process's physical or chemical nature, the sorption mechanism, and the rate-controlling step (Kang & Kim, 2019;Wu et al. 2009). Pseudo-first order (PFO), Pseudo-second order (PSO), and intraparticle diffusion (IPD) kinetic models (Bayuo et al., 2020(Bayuo et al., , 2023bKang & Kim, 2019) were used to figure out the kinetics of uranium sorption from aqueous solution onto bio-char adsorbents PBC, PBC-Zn, and PBC-SA. Table S1 declares the linear forms of the applied models (Bayuo et al., 2020(Bayuo et al., , 2023bKang & Kim, 2019). ...
... Pseudo-first order (PFO), Pseudo-second order (PSO), and intraparticle diffusion (IPD) kinetic models (Bayuo et al., 2020(Bayuo et al., , 2023bKang & Kim, 2019) were used to figure out the kinetics of uranium sorption from aqueous solution onto bio-char adsorbents PBC, PBC-Zn, and PBC-SA. Table S1 declares the linear forms of the applied models (Bayuo et al., 2020(Bayuo et al., , 2023bKang & Kim, 2019). The values of model terms can be achieved from the linear plots of ln (q e -q t ) versus t ( PFO plot), t/q t versus t (PSO plot), and the slope of the q t vs t½ (IPD plot) (El-Sabbagh et al., 2023). ...
Carbonaceous materials produced from agricultural waste (palm kernel shell) by pyrolysis can be a proper type of low-cost adsorbent for wide uses in radioactive effluent treatment. In this context, the as-produced bio-char (labeled as PBC) and its sub-driven sulfuric acid and zinc oxide activated carbons (labeled as PBC-SA, and PBC-Zn respectively) were employed as adsorbents for uranium sorption from aqueous solution. Various analytical techniques, including SEM (Scanning Electron Microscopy), EXD (X-ray Diffraction), BET (Brunauer–Emmett–Teller), FTIR (Fourier Transform Infrared Spectroscopy), and Zeta potential, provide insights into the material characteristics. Kinetic and isotherm investigations illuminated that the sorption process using the three sorbents is nicely fitted with Pseudo-second-order-kinetic and Langmuir isotherm models. The picked data display that the equilibrium time was 60 min, and the maximum sorption capacity was 9.89, 16.8, and 21.9 mg/g for PBC, PBC-SA, and PBC-Zn respectively, which reflects the highest affinity for zinc oxide, activated bio-char, among the three adsorbents, for uranium taking out from radioactive wastewater. Sorption thermodynamics declare that the sorption of U(VI) is an exothermic, spontaneous, and feasible process. About 92% of the uranium-loaded PBC-Zn sorbent was eluted using 1.0 M CH3COONa sodium ethanoate solution, and the sorbent demonstrated proper stability for 5 consecutive sorption/desorption cycles.
... Bayuo et al. optimized biosorption of hexavalent chromium using RSM from aqueous media. The results revealed that the maximum adsorption capacity was achieved 2.355 mg/g when the contact time, pH, initial Cr(VI) concentration were 120 min, 8.0, and 50 mg/L [21]. ...
... Thus, it should be carried out in further studies to demonstrate chitosan-based adsorbent's potential in nitrite adsorption. Additionally, new research methods such as process intensification [74,75] and data-driven modeling with machine learning [76,77] have been successfully applied in the study of the adsorption process in chemical engineering. These powerful new methods can discover complex and nonlinear relationships between independent parameters and predict the required conditions with high accuracy, which are highly desirable in further studies. ...
... ANOVA analysis was performed to assess model fit in predicting Cr (VI) adsorption and the summary statistics of model fit are shown in Table 3. ANOVA, is particularly useful in situations where there are multiple factors or variables that can influence the outcome. By incorporating both model and experimental error, ANOVA provides a comprehensive analysis of the significance of the model to the observed data [58]. Therefore, the F-value (29.63) of the model suggested that the variables included in the model have a strong relationship with the outcome variable, indicating that the model is significant and accurate. ...
The study utilized a ZnCl2-impregnated biochar mixture from banana peel and corncob for treating Cr(VI) in tannery industries. The thermal stability of the raw sample and the crystallinity of the activated adsorbent were characterized by thermogravimetric analysis-differential thermogravimetry (TGA–DTG) and X-ray powder diffraction (XRD) methods. The effects of parameters such as contact time (25–45 min), pH (1–3), biochar dose (0.2–0.6 g), and initial Cr(VI) concentration (10–30 mg L–1) on the treatment of Cr(VI) contaminated wastewater from tannery were thoroughly investigated and optimized using the response surface method (RSM). The kinetic and isotherm models were evaluated. The TGA analysis revealed that the temperature range for biochar preparation begins at 500˚C. The XRD analysis confirmed the presence of crystalline surface structures, indicating well-formed biochar. The maximum Cr(VI) removal effectiveness of 98.95 ± 0.375%, 87.19 ± 0.28%, and 85.02 ± 0.21% were found for synthetic solutions, East Africa Tannery PLC and Houdao Chen/Pelle Leather Production, respectively, at optimal conditions of contact time of 34.40 min, pH 2.05, a biochar dose of 0.354 g, and an initial Cr(VI) concentration of 23.02 mg L–1. The findings also suggested that the pseudo second order kinetic model best describes the adsorption process. The experimental results were best fitted by the Langmuir isotherm model, which produced a maximum adsorption capacity of 35.84 mg g–1. In summary, the use of a mixed adsorbent consisting of banana peel and corn cob activated with 8% ZnCl2, proved to be highly effective and the best candidate for removing Cr(VI) in tannery wastewater.
Keywords: Adsorption Mechanisms; Hexavalent Chromium; Kinetic and Isotherm Model; Optimization; Tannery Wastewater
... Due to its efficacy, and availability, the utilization of natural, domestic, and agricultural wastes has attracted considerable interest in the last few years to remove chromium (VI) and other heavy metals from wastewater by adsorption processes (Bayuo et al. 2022;Bayuo et al. 2021;Bayuo et al. 2020;Bayuo et al. 2019;Zakaria et al. 2023). The polyamine-modified carbon nanotubes (PA-CNTs) have been introduced to remove Cr(VI) (Liu et al. 2023;Jia et al. 2022). ...
In the leather industry, 8–12% of chromium compound is used in tanning and around 60–70% of the applied chromium is consumed by the leather fibre and the rest of them are discharged to the effluent. This chromium has an adverse impact on the environment as well as on humans. Chromium (III) can be oxidized into chromium (VI) in many ways which are considered carcinogenic as well as mutagenic. Activated carbon generated from liming pelt trimming which is left over as a tannery solid waste with vegetable tannin (mimosa) was employed to investigate chromium (VI) adsorption from aqueous solutions. Activated carbon was prepared in a muffle furnace at 600 o C in the presence of sulfuric acid. Batch tests were performed to determine how several factors, such as pH, contact time, adsorbent dosage, initial chromium content, and temperature affected the adsorption process. The excellent maximum chromium (VI) removal efficiency was found 99.15% from aqueous solutions at pH 1 and an adsorbent dosage of 15 g/L. According to the kinetic investigation, the chromium (VI) removal by the activated carbon followed a pseudo-second-order kinetic with an R ² of 0.9889. Thermodynamic parameters including ΔG o , ΔH o , and ΔS o revealed that the adsorption of chromium ions on the activated carbon was exothermic and spontaneous. The results prove that chromium (VI) could be removed from industrial wastewater using a very promising, cost-efficient biosorbent made from tannery solid waste. The novelty of the current approach is to utilize the tannery solid waste as an adsorbent to reduce the dangerous chemicals from the wastewater where pollutants will be eliminated by the treatment of waste.
