| Certain kinds of chlorine-containing organic compounds could be formed in tapping water after disinfected by chlorine, because of the trace nature organic compounds existed in surface water. Fe-Si+Mg-Al is the mixture of Fe-Si alloy particles and Mg-Al alloy particles. It has been shown in our former study that clorine-containing organic compounds in water could be degraded when using Fe-Si+Mg-Al as filter material. In this thesis, systemical study on reaction mechanism as well as reaction kinetics of trichloroacetic acid (TCAA) degraded by Fi-Si+Mg-Al was reported.In this study, trace TCAA and its several degradation products in water was determined simultaneously by ion chromatography. The change in TCAA concentration was detected under different conditions, such as filter material with different ratio, different TCAA initial concentration, or at different reaction temperature. Based on the results, mechinsm and kinetics of the degradation reaction were discussed.The couple interaction between Fe-Si alloy particles and Mg-Al alloy particles was confirmed to accelerate the reductively degradation of TCAA. The degradation pathway of TCAA was speculated to remove chlorine atoms one by one. The degradation rate of TCAA was found to be related to the amount or particle size of the composition material and stirring speed. The dechlorination reaction of TCAA follows pseudo-first-order reaction kinetics when TCAA in low concentration, and the order between 0-1 when the concentration of TCAA was high. The active energy of the degradation reaction was calculated to be 26.40kJ/mol. |
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