Oxidation mechanisms of all kinds of active substances by hybrid photoelectrocatalytic treatment
TANG Jian-wei1,2, LI Meng1, LI Zhao-dong1
1. Department of Civil Engineering, Wuhan University of Science and Technology, Wuhan 430070, China;
2. People's Liberation Army of China 95338, Guangzhou 510405, China
Refractory 3,4-dimethylaniline wastewater was studied for the oxidation mechanisms of various active substances generated in the HPECO process and the contribution degree (kf/K) based on kinetics was utilized to evaluate the oxidation effect of each active substance. The results showed that the contribution degrees of active chlorines and hydroxyl radicals were respectively 89.03% and 6.24% and the contribution of hole and anode direct oxidation was negligible. The holes, hydroxyl radicals and free chlorine were determined respectively by the ways of melamine, dimethylsulfoxide and DPD and the results showed that the contribution degrees of holes and ·OH were decreased due to high concentration of sodium chloride and ·OH yield followed the zero-order kinetic law with the rate of 0.106mg/(L·min). Moreover, the cumulative concentration regulation of free chlorine was divided into three stages with the rate of 0.159mg/(L·min) in the third stage. Free chlorine only accounted for a small portion in active chlorines, while the oxidation of other chlorinated oxides and chlorinated free radicals played important roles. By GC-MS, UV-vis and TOC determination, it showed that in the initial 10.0min, the active chlorines attacked the side chains rapidly, so that 3, 4-DMA could be converted into benzaldehyde and other benzene derivatives. After 10.0min, the benzene derivatives were attacked towards the π bonds by ·OH and transformed into small molecules which could be finally mineralized.
唐建伟, 李孟, 李肇东. 光电催化氧化处理中各类活性物质的氧化机理[J]. 中国环境科学, 2019, 39(5): 2048-2054.
TANG Jian-wei, LI Meng, LI Zhao-dong. Oxidation mechanisms of all kinds of active substances by hybrid photoelectrocatalytic treatment. CHINA ENVIRONMENTAL SCIENCECE, 2019, 39(5): 2048-2054.
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