Ultrasound-assisted adsorption of Sunset Yellow CFC dye onto Cu doped ZnS nanoparticles loaded on activated carbon using response surface methodology based on central composite design

A novel metal-free perylene-functionalized graphite adsorbent for efficient antibiotic removal from wastewater

Adsorption remains a widely utilized and effective technique for removing chemical contaminants from polluted water, and novel adsorbents are currently in the process of being developed. The presence of antibiotics residues in aqueous effluents is a potential concern due to their potential adverse effects on living organisms. In this work, perylene tetracarboxylic acid-functionalized expanded graphite (PTCA-EG) was synthesized as a metal-free adsorbent and its potential for efficient treatment of contaminated wastewater with cefalexin (CLX) antibiotic was studied. The experimental variables were modeled and optimized using central composite design (CCD) and response surface methodology (RSM) to maximize adsorption efficiency. In this regard, the contact time of 20 min, solution pH of 7.0, adsorbent dosage of 18 mg, and initial CLX concentration of 45 mg L-1 were found to be the optimum conditions for adsorptive removal of CLX with a maximum efficiency of 99 ± 1.21%. In addition, the adsorption equilibrium data were well analyzed with isotherm, kinetic, and thermodynamic studies. The isotherm results revealed the adsorption process was favorable and took place on the heterogeneous surface. Moreover, the Langmuir maximum adsorption capacity (Qmax) was determined as 220.7 mg g-1. Also, thermodynamic parameters revealed the spontaneity and endothermic nature of the adsorption process. The reusability studies demonstrated that the spent PTCA-EG can be easily regenerated through NaOH solution (0.01 mol L-1) and reused for six cycles without any significant decrease in its adsorption efficiency. Also, the PTCA-EG showed excellent behavior in adsorptive removal of CLX in real water samples including river water (96.61 ± 1.82%) and hospital effluents (91.91 ± 3.41-93.69 ± 3.06%).

Modeling sunset yellow removal from fruit juice samples by a novel chitosan-nickel ferrite nano sorbent

Analysis of food additives is highly significant in the food industry and directly related to human health. This investigation into the removal efficiency of sunset yellow as an azo dye in fruit juices using Chitosan-nickel ferrite nanoparticles (Cs@NiFe2O4 NPs). The nanoparticles were synthesized and characterized using various techniques. The effective parameters for removing sunset yellow were optimized using the response surface methodology (RSM) based on the central composite design (CCD). Under the optimum conditions, the highest removal efficiency (94.90%) was obtained for the initial dye concentration of 26.48 mg L-1 at a pH of 3.87, a reaction time of 67.62 min, and a nanoparticle dose of 0.038 g L-1. The pseudo-second-order kinetic model had a better fit for experimental data (R2 = 0.98) than the other kinetic models. The equilibrium adsorption process followed the Freundlich isotherm model with a maximum adsorption capacity of 212.766 mg g-1. The dye removal efficiency achieved for industrial and traditional fruit juice samples (91.75% and 93.24%), respectively, confirmed the method's performance, feasibility, and efficiency. The dye adsorption efficiency showed no significant decrease after five recycling, indicating that the sorbent has suitable stability in practical applications. variousThe synthesized nanoparticles can be suggested as an efficient sorbent to remove the sunset yellow dye from food products.

A feasible approach for azo-dye methyl orange degradation in siderite/H2O2 assisted by persulfate: Optimization using response surface methodology and pathway

Siderite was applied to the binary oxidant system of siderite-catalyzed hydrogen peroxide (H₂O₂) and enhanced with persulfate (PS). In the absence of PS, methyl orange (MO) almost could not be degraded by the siderite/H₂O₂ process. However, adding PS significantly improved the capacity of MO to oxidize azo-dye. The influence of individual and interaction of reaction factors have been explored with a simple response surface methodology (RSM) based on central composite design (CCD). The quadratic model with low probabilities (<0.0001) at a confidence level of 95% was satisfactory to predict MO degradation in siderite/H₂O₂/PS system, whose correlation coefficients of R² and R²-adj were 0.9569 and 0.9264, respectively. Moreover, the optimum operation conditions of 21.20 mM, 2.75 g/L, 3.86 mM, and 4.69 for H₂O₂, siderite, PS and initial pH, respectively with the response of C/C₀ around 0.047. Radical scavenging experiments and electron spin resonance (ESR) determined that ·OH was crucial for MO degradation, while the contribution of SO₄^·- was minor. The surface morphology and iron content of siderite before and after the oxidation process showed clear differences. Possible intermediates and a degradation pathway were proposed based on the results of UV-Vis spectral and GC-MS analysis. Moreover, the toxicity to Vibrio fischeri bioluminescent bacterium has increased in the earlier degradation stage due to the generated by-products and weaken with the continuous treatment. This study demonstrated that the siderite/H₂O₂/PS system was effective over a relatively wide pH range without producing secondary pollutants, making it a promising technology and potential environmentally benign approach to azo-dye wastewater treatment.

Green Production of Zero-Valent Iron (ZVI) Using Tea-Leaf Extracts for Fenton Degradation of Mixed Rhodamine B and Methyl Orange Dyes

The danger from the content of dyes produced by textile-industry waste can cause environmental degradation when not appropriately treated. However, existing waste-treatment methods have not been effective in degrading dyes in textile waste. Zero-valent iron (ZVI), which has been widely used for wastewater treatment, needs to be developed to acquire effective green production. Tea (Camellia sinensis) leaves contain many polyphenolic compounds used as natural reducing agents. Therefore, this study aims to synthesize ZVI using biological reducing agents from tea-leaf extract and apply the Fenton method to degrade the color mixture of rhodamine B and methyl orange. The results show that the highest polyphenols were obtained from tea extract by heating to 90 °C for 80 min. Furthermore, PSA results show that ZVI had a homogeneous size of iron and tea extract at a volume ratio of 1:3. The SEM-EDS results show that all samples had agglomerated particles. The ZVI 1:1 showed the best results, with a 100% decrease in the color intensity of the dye mixture for 60 min of reaction and a degradation percentage of 100% and 66.47% for rhodamine B and methyl orange from LC-MS analysis, respectively. Finally, the decrease in COD value by ZVI was 92.11%, higher than the 47.36% decrease obtained using Fe(II).

Exploration on Optimized Control Way of D-Amino Acid for Efficiently Mitigating Membrane Biofouling of Membrane Bioreactor

The thorny issue of membrane biofouling in membrane bioreactors (MBR) calls for new effective control measures. Herein, D-amino acid (DAA) was employed to mediate MBR membrane biofouling by inhibiting biofilm information and disintegrating formed biofilm. Different DAA control ways involving membrane property, DAA-adding timing, and DAA-control mode were explored through experiments and the multiple linear regression model and the response surface methodology. The optimized DAA control ways were acquired, involving DAA used as an active agent, and the DAA-adding timing of 4 h cultured before running, as well as both hydrophilic and hydrophobic membrane, resulting in an approximately 40.24% decrease in the membrane biofouling rate in comparison with the conventional MBR. DAA is an efficient membrane biofouling mediating approach for MBR under optimized control ways combination and a facile solution for solving membrane biofouling in actual membrane systems.

Degradation of bisphenol A by persulfate coupled with dithionite: Optimization using response surface methodology and pathway

The degradation efficiency of bisphenol A (BPA) was investigated in the process of persulfate (PS) coupled with dithionite (DTN) as a function of concentration of BPA, PS, DTN and solution pH. A simple response surface methodology (RSM) based on central composite design (CCD) was employed to determine the influence of individual and interaction of above variables and the optimum processing parameters. It is satisfactory of a quadratic model with low probabilities (<0.0001) at a confidence level of 95% to predict the BPA degradation efficiency. The model was well fitted to the actual data and the correlation coefficients of R² and R²-adj were 0.9270 and 0.8885, respectively. In addition, the obtained optimum conditions for BPA degradation were 1.79 μM, 131.77 μM, 93.64 μM for BPA, PS, DTN and pH = 3.62, respectively. It achieved a degradation efficiency >90% within 150 min. Moreover, the trapping experiment of active species demonstrated that SO₄^·- and ·OH were the dominant species and natural water matrix showed an obvious inhibition effect on BPA degradation. The BPA degradation pathway was predicted based on GC-MS results in this study.

Utilization of agroindustrial wastes for the production of laccase by Achromobacter xylosoxidans HWN16 and Bordetella bronchiseptica HSO16

Agroindustrial residual lignocellulosic biomaterial provides an economical and renewable natural bioresource for the large-scale, gainful biofuel production, as well as the production of fine bulk chemicals, which may include industrial biocatalysts. To this end, the laccase-inducing aptitude of some agroindustrial, lignocellulosic residues were appraised in submerged fermentation batch culture of two woodland betaproteobacteria (Hb9c; Achromobacter xylosoxidans HWN16, Hb16c; Bordetella bronchiseptica HSO16). Significant fermentation factors for laccase production were identified following a one-variable-at-a-time: OVAT screening method, levels of significant factors were optimized using response surface methodology: RSM. Mandarin peelings: MP and wheat bran: WB were suitable substrates for laccase production in Hb9c; 29.4 U/mL and Hb16c; 28.2 U/mL, respectively. However, the numerical optimization of significant factors for laccase production in both isolates presented an overall maximum laccase output encountered throughout the study (Hb9c; 169.39 U/mL, Hb16c; 45.22 U/mL), albeit the simulated conditions of the statistical model were outside the design space of the algorithm such as pH 5, 0.5 g MP, 100 rpm, 0.25 g NaNO₃ for Hb9c and pH 3, 2.5 g WB, 50 rpm, 0.05 g yeast extract for Hb16c. Furthermore, a record 17.5 and 15.54 fold increase in laccase turnover depicts the astuteness of the statistical method in the valorization of these lignocellulosic residues for enhanced laccase production, hence, the incorporation of these outcomes at industrial scales might yield tremendous outputs.

Biosorption of anionic and cationic dyes via raw and chitosan oligosaccharide-modified Huai Flos Chrysanthemum at different temperatures

Raw Huai Flos Chrysanthemum (HFC) and modified HFC (HFC@CO) were used for the first time as a biosorbent material to remove cationic dyes Malachite green (MG) and Crystal violet (CV), and anionic dyes Sunset yellow (SY), Lemon yellow (LY), and Carmine (CM), at different temperatures (5–50 °C). The highest removal rates (R) for dye adsorption were observed at low temperature (5 °C) and room temperature (20 °C). At high (500 mg L⁻¹) dye concentration, adsorption was completed within one minute, but the time required to reach adsorption equilibrium was longer than at the low (20 mg L⁻¹) concentration. The experimental data fitted very well to the Langmuir model and the values of the maximum adsorption capacity for SY, LY, CM, CV, and MG, were 481.41, 507.23, 141.78 mg g⁻¹, 526.32, and 769.23 mg L⁻¹, respectively. The adsorption data fit well to a pseudo-second-order kinetic model.

Raw Huai Flos Chrysanthemum and modified HFC were used for the first time as a biosorbent to remove cationic dyes Malachite green and Crystal violet, and anionic dyes Sunset yellow, Lemon yellow, and Carmine, at different temperatures (5–50 °C).

Synthesis of nanocomposites of iron oxide/gold (Fe3O4/Au) loaded on activated carbon and their application in water treatment by using sonochemistry: Optimization study

This paper focuses on the finding best operational conditions using response surface methodology (RSM) for Rhodamine123 (R123) and Disulfine blue (DSB) dyes removal by ultrasound assisted adsorption onto Au-Fe₃O₄ nanoparticles loaded on activated carbon (Au-Fe₃O₄ NPs-AC). The influences of variables such as initial R123 (X₁) and DSB concentration (X₂), pH (X₃), adsorbent mass (X₄) and sonication time (X₅) on their removal were investigated by small central composite design (CCD) under response surface methodology. The significant variables and the possible interactions among variables were investigated and estimated accordingly. The best conditions were set as: 4min, 4.0, 0.025g, 13.5 and 26.5mgL^-1 for sonication time, pH, adsorbent weight, initial R123 and DSB concentration, respectively. At above conditions, the adsorption equilibrium and kinetic follow the Langmuir isotherm and pseudo-second-order kinetic model, respectively. The maximum monolayer capacity (Q_max) of 71.46 and 76.38mgg^-1 for R123 and DSB show sufficiency of model for well presentation of experimental data.

Investigate the ultrasound energy assisted adsorption mechanism of nickel(II) ions onto modified magnetic cobalt ferrite nanoparticles: Multivariate optimization

In present study, magnetic cobalt ferrite nanoparticles modified with (E)-N-(2-nitrobenzylidene)-2-(2-(2-nitrophenyl)imidazolidine-1-yl) ethaneamine (CoFe₂O₄-NPs-NBNPIEA) was synthesized and applied as novel adsorbent for ultrasound energy assisted adsorption of nickel(II) ions (Ni²⁺) from aqueous solution. The prepared adsorbent characterized by Fourier transforms infrared spectroscopy (FT-IR), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and X-ray diffraction (XRD). The dependency of adsorption percentage to variables such as pH, initial Ni²⁺ ions concentration, adsorbent mass and ultrasound time were studied with response surface methodology (RSM) by considering the desirable functions. The quadratic model between the dependent and independent variables was built. The proposed method showed good agreement between the experimental data and predictive value, and it has been successfully employed to adsorption of Ni²⁺ ions from aqueous solution. Subsequently, the experimental equilibrium data at different concentration of Ni²⁺ ions and 10mg amount of adsorbent mass was fitted to conventional isotherm models like Langmuir, Freundlich, Tempkin, Dubinin-Radushkevich and it was revealed that the Langmuir is best model for explanation of behavior of experimental data. In addition, conventional kinetic models such as pseudo-first and second-order, Elovich and intraparticle diffusion were applied and it was seen that pseudo-second-order equation is suitable to fit the experimental data.

Multi-responses optimization of simultaneous biosorption of cationic dyes by live yeast Yarrowia lipolytica 70562 from binary solution: Application of first order derivative spectrophotometry

Present study is based on application of live yeast Yarrowia lipolytica 70562 as new biosorbent was investigated for the simultaneous biosorption of Crystal Violet (CV) and Brilliant Green (BG) from wastewater. The effect of operating parameters such as initial dye concentrations (6-14mgL^-1), solution pH (4.0-8.0) and contact time (4-20h) was investigated by response surface methodology (RSM) for modeling and optimization of biosorption process and accordingly the best operational conditions was set as: initial CV and BG concentration of 8.0, and 10mgL^-1, pH of 7.0 and contact time of 16h. Above specified conditions lead to achievement of maximum biosorption of 98.823% and 99.927% for CV and BG dyes, respectively. The experimental equilibrium data well explained according to Langmuir isotherm model with maximum biosorption capacity of 65.359 and 56.497mgg^-1 for BG and CV, respectively. The second order and intraparticle diffusion models as cooperative mechanism has high efficiency and performance for interpretation of real data.

Optimization of peak current of poly(3,4-ethylenedioxythiophene)/multi-walled carbon nanotube using response surface methodology/central composite design

Modification of electrode surface with poly(3,4-ethylenedioxythiophene)/multi-walled carbon nanotube (PEDOT/MWCNT) composite prepared by electrodeposition technique was reported in this study.

Adsorption behavior of modified Iron stick yam skin with Polyethyleneimine as a potential biosorbent for the removal of anionic dyes in single and ternary systems at low temperature

The skin of Iron stick yam (ISY) was modified with Polyethyleneimine (ISY@PEI) and evaluated for use as a potential biosorbent to remove the anionic dyes Sunset yellow (SY), Lemon yellow (LY), and Carmine (CM) from wastewater under low temperature conditions (5-15°C) in single and ternary dye systems. Both in the single and ternary systems, experimental data showed that adsorption capacity reached the highest value at 5°C, and adsorption capacity decreased when the temperature increased (10-50°C). The equilibrium data fitted very well to the Langmuir model and the extended Langmuir isotherm, for the single and ternary systems, respectively. The maximum adsorption capability was 138.92, 476.31, and 500.13mg/g for LY, SY, and CM, respectively, in a single system and 36.63, 303.31, and 294.12mg/g for LY, SY, and CM, respectively, in a ternary system. The adsorption followed pseudo-second-order kinetics. The thermodynamic parameters indicated that it was a spontaneous and exothermic process.