Effect of Sulfate and Nitrate Anions on the Oxidative Degradation of Tetrachloroethylene by Magnetite with Glutathione

Abstract

This work demonstrates the effect of sulfate \( {({\text{SO}}_{4}}^{2 - } ) \) and nitrate \( {({\text{NO}}_{3}}^{ - } ) \) anions during the oxidative degradation of tetrachloroethylene (PCE) by magnetite (Fe3O4) with glutathione. The enhanced of oxidative degradation of PCE was achieved due to the presence of \( {{\text{SO}}_{4}}^{2 - } \) and \( {{\text{NO}}_{3}}^{ - } \) anions to form reactive radicals in the Fe3O4-glutathione system. Kinetic rate constants for the oxidative degradation of PCE were accelerated 1.8 and 2.7 times higher, from 0.020 min−1 in the PCE-Fe3O4-glutathione to 0.036 and 0.054 min−1 in the PCE-Fe3O4-glutathione-\( {{\text{NO}}_{3}}^{ - } \) and PCE-Fe3O4-glutathione-\( {{\text{SO}}_{4}}^{2 - } \) systems respectively. The experimental results reveal that the oxidative degradation kinetic rate constant of PCE are strongly dependent on the presence of \( {{\text{SO}}_{4}}^{2 - } \) and \( {{\text{NO}}_{3}}^{ - } \) radicals. Kinetic oxidative degradation rate constant of PCE increased proportionally as the concentrations of \( {{\text{NO}}_{3}}^{ - } \) (0.036–0.120 min−1) and \( {{\text{SO}}_{4}}^{2 - } \) (0.0540–0.160 min−1) increased from 1 to 10 ppm at pH 7. The significant finding of this study is to provide the understanding of the oxidative degradation of PCE by Fe3O4 with glutathione in hyporheic zone and groundwater containing the \( {{\text{SO}}_{4}}^{2 - } \) and \( {{\text{NO}}_{3}}^{ - } \) anions for the development of novel remediation technolojgies.