AWAM International Conference on Civil Engineering 2019 (AICCE'19) - Nibong Tebal - Malaysia (2019-08-21)

Effect of sulfate and nitrate anions on the oxidative degradation of tetrachloroethylene by magnetite with glutathione
This work demonstrates the effect of sulfate 〖(SO〗_4^(2-)) and nitrate 〖(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 SO_4^(2-) and NO_3^- anions that act as a catalyst to form reactive radicals in the Fe3O4-glutathione system. Kinetic rate constant for the oxidation degradation of PCE was accelerated 1.8 times higher, from 0.0035±0.0094 hr−1 in the Fe3O4-glutathione system to 0.0060±0.0098 hr−1 in the Fe3O4-glutathione-NO_3^- system. Contrarily, the oxidative degradation kinetic rate of PCE by Fe3O4-glutathione-SO_4^(2-) system was slightly faster as compared to experimental in the presence of NO_3^- anions that the increased of the kinetic rate constant was 2.5 times higher, from 0035±0.0094 hr−1 in the Fe3O4-glutathione system to 0.0085±0.0086 hr−1 in the Fe3O4-glutathione-SO_4^(2-)system. . SO_4^(2-) and NO_3^- anions were transformed to sulfate radical (SO_4^•) and nitrate radical 〖(NO〗_3^•) anions were transformed to sulfate radical (SO_4^•) and nitrate radical 〖(NO〗_3^•) in the presence of hydroxyl OH. radicals. The experimental results reveal that the oxidative degradation kinetic rate constant of PCE are strongly dependent on the present of SO_4^(2-) and〖 NO〗_3^- radicals. Kinetic oxidative degradation rate constant of PCE increased proportionally as the concentrations of NO_3^- (0.0060 ± 0.0098 – 0.020 ± 0.0086 hr−1) and SO_4^(2-) (0.0085 ± 0.0086 – 0.030 ± 0.0090 hr−1) increased from 1ppm to 10 ppm at pH 7. This study reveals that the novelty finding on the potential of SO_4^(•-) and NO_3^• radicals as a catalyst to enhance oxidative degradation of PCE by Fe3O4 in the presence of glutathione. 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 SO_4^(2-) and NO_3^- anions for the development of novel remediation technologies.
Mrs. Nur Dalila Mohamad