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In this study, chitosan was modified with cellulose and gelatin for the removal of Cu2+, Fe2+, and Pb2+ from oily wastewater. Chitosan was characterized using Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X‐ray diffraction (XRD). Carbon (77.54%), hydrogen (10.30%), oxygen (8.89%), nitrogen (2.74%), and sulphur (0.53%) were found in the organic constitution of the oil utilized, according to elemental analysis. Despite the presence of other metal ions in the used oil and effluent, this study focused solely on Cu2+, Fe2+, and Pb2+. Studies on the removal of Cu2+, Fe2+, and Pb2+ from oily wastewater were conducted, and multiple effect factors such as temperature and pH, time and pH, solvent and pH, temperature and time, temperature and solvent, and time and solvent were evaluated. An adsorption study was performed to remove the heavy metals. The results revealed that the highest percentage removal of Cu2+ was 96.62 (pH = 7.52 and conductivity = −12 mV), of Fe2+ was 97.95 (pH = 6.30 and conductivity = +68 mV), and of Pb2+ was 98.86 (pH = 10.58 and conductivity = −170 mV). To analyze the impacts of experimental factors, experiments were developed using central composite design (CCD) based on response surface methodology (RSM). [ABSTRACT FROM AUTHOR]

Natural clinoptilolite was modified with dialkylphosphinic and succinic acid for the selective removal of Co2+, Cu2+, Zn2+, Ni2+ and Fe2+. The natural and modified materials were characterized using x-ray diffraction (XRD), xray fluorescence (XRF), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis. Batch experiment was conducted as a function of contact time, pH, clinoptilolite mass and temperature. The higher removal efficiency was obtained under the following optimal conditions: contact time 240 min, pH 6, the mass of modified clinoptilolite 6 g and temperature 45oC. The experimental data fit satisfactory to Langmuir and Dubinin-Radushkevich (D-R) isotherm models as well as pseudo-second order kinetic. Thermodynamic parameters such as Gibb's free energy change (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were calculated. The ion exchange process was found to be spontaneous, endothermic and randomness. The selectivity of clinoptilolite towards heavy metals from industrial wastewater was in the sequence: Co2+ > Cu2+ > Zn2+ > Ni2+ > Fe2+. The effect of the acid concentration in elution was also investigated. [ABSTRACT FROM AUTHOR]

Natural clinoptilolite was modified with dialkylphosphinic and succinic acid for the selective removal of Co2+, Cu2+, Zn2+, Ni2+ and Fe2+. The natural and modified materials were characterized using x-ray diffraction (XRD), xray fluorescence (XRF), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis. Batch experiment was conducted as a function of contact time, pH, clinoptilolite mass and temperature. The higher removal efficiency was obtained under the following optimal conditions: contact time 240 min, pH 6, the mass of modified clinoptilolite 6 g and temperature 45oC. The experimental data fit satisfactory to Langmuir and Dubinin-Radushkevich (D-R) isotherm models as well as pseudo-second order kinetic. Thermodynamic parameters such as Gibb’s free energy change (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were calculated. The ion exchange process was found to be spontaneous, endothermic and randomness. The selectivity of clinoptilolite towards heavy metals from industrial wastewater was in the sequence: Co2+ > Cu2+ > Zn2+ > Ni2+ > Fe2+. The effect of the acid concentration in elution was also investigated. [ABSTRACT FROM AUTHOR]

In this study, the ozonolysis of real anaerobically digested distillery wastewater (DWW) was carried out. The effect of operating parameters, such as pH, initial concentration, and ozone dosage, on the efficiency of ozone utilization, color removal, and sludge solubilization was studied. The highest ozone utilization of 99% was observed at the highest initial concentration (COD of 3000 mg/L) and lowest ozone flowrate (22.5 mg O3/L/min), but with a very low color reduction of 20%, after 60 minutes of ozonolysis. To achieve a higher color reduction >80% and at ozone utilization >95%, the DWW had to be diluted twice (COD 1500 mg/L), and the flowrate doubled to 45 mg O3/L/min. The reduction in color signified the oxidation of the color causing biorecalcitrant aromatic melanoidin compounds. This was confirmed by the 47% reduction in ultraviolet absorbance at 254 nm indicating the breakdown of the complex aromatic compounds into low molecular weight organics. Moreover, increases in average oxidation state from −0.6 to −0.2 suggested a decline in aromaticity and formation of easily biodegradable aliphatic compounds. The ozonolysis process was found to follow the first-order reaction kinetic model with the highest rate constant of 0.0326 min−1 obtained. A reduction in suspended COD by 88% indicated solubilization of the sludge contained in the effluent. [ABSTRACT FROM AUTHOR]