J. Mehralipour, M. Kermani
May 4, 2021
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0
Influential Citations
10
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Journal
Journal of Environmental Health Science and Engineering
Abstract
2–4 Dichlorophenoxy acetic acid is most publicly applied from chlorinated phenoxy acids herbicides. In this research, central composite design for optimization of photo-Elecro/persulfate/nZVI process to degradation and mineralization of this herbicide in aqueous solution to environment protection was applied. The initial pH (2–4), persulfate anion concentration (0.25–0.5 mg/L), direct electrical (0.5–1 A), herbicide concentration (50–100 mg/l), nZVI dose (0.05–1 mg/L), and reaction time (50–100 mg/l) are independent variables optimized. Also, the synergist effect, COD and TOC removal, the effect of radical scavengers, and by-products were investigated. The fitting of the model, suggested a quadratic model (R2 = 0.9926). F-value and P value of ANOVA were 719.81 and 0.0001 respectivelty. After optimizing the PEP/nZVI process, the proposed optimal conditions was pH = 3.4, persulfate concentration equal to 0.49 mg/l, in 1 A direct current, nZVI dose equal to 0.1 mg/l, in 50.05 mg/l herbicide concentration as an initial concentration, in 80 min reaction time. The theoretical and actual removal was evaluated 91.99% and 92%, respectively. In the optimum condition, 45.4% synergist effect indicated. 78.3% and 66.5% of initial COD and TOC were decreased. 39.02% of Cl ion was released form 2,4-D structure. The presence of radical scavengers have an adverse impact on the performance of process. The highest amount of radical scavenging was in methanol, tert-butyl alcohol and bicarbonate ions at concentrations at 50 mM/l. The kinetic data was fitted via pseudo-first-order reaction (R2 = 0.99).The direct and indirect oxidation process lead to formation of several organic by-products which were confirmed by GC-MS analysis.