水环境
皮运正,王建龙.臭氧氧化水中2,4,6-三氯酚的反应机理研究[J].环境科学学报,2005,25(12):1619-1623
臭氧氧化水中2,4,6-三氯酚的反应机理研究
- The pathway of the ozonation of 2,4,6-trichlorophenol in aqueous solution
- 基金项目：国家自然科学基金(No.50325824);中国博士后科学基金
- 作者
- 单位
- 皮运正
- 清华大学核能与新能源研究院环境技术研究室, 北京 100084
- 王建龙
- 清华大学核能与新能源研究院环境技术研究室, 北京 100084
- 摘要：研究了臭氧氧化对2,4,6-三氯酚的去除效果,以及氧化过程中过氧化氢、氯离子、甲酸和乙二酸的变化情况,探讨了臭氧氧化2,4,6-三氯酚的反应机理和反应途径.实验结果表明,如果溶液中没有自由基清除剂,在臭氧投加量为24mg·L-1时,0.1mmol·L-1的2,4,6-三氯酚在6min内,去除率可达99%.臭氧分子氧化2,4,6-三氯酚的过程中产生过氧化氢,检测到的过氧化氢的最大摩尔浓度为初始2,4,6-三氯酚摩尔浓度的22.5%.中间产物过氧化氢随后和臭氧反应生成大量的羟基自由基,此时2,4,6-三氯酚是被臭氧和羟基自由基联合氧化,生成甲酸和乙二酸.当溶液中含有大量的自由基清除剂时,2,4,6-三氯酚首先被臭氧分子氧化成黄色的氯代对苯醌,然后氧化成甲酸和乙二酸.臭氧氧化2,4,6-三氯酚存在臭氧分子氧化以及O3/OH.联合氧化两种反应途径.
- Abstract：The reaction mechanism and pathway of the ozonation of 2,4,6-trichlorophenol (2,4,6-TCP) in aqueous solution were investigated. The removal efficiency and the variation of H2O2, Cl-, formic acid and oxalic acid were studied during the ozonation process. The results showed that when there was no scavenger, the removal efficiency of (0.1 mmol·L-1)2,4,6-TCPcould reach 99% within6 min by adding (24 mg·L-1) ozone. The reaction of molecular ozone with 2,4,6-TCPresulted in the formation of H2O2. The maximal concentration of H2O2 detected during the ozonation could reach 22.5% of the original concentration of 2,4,6-TCP. The reaction of ozone with H2O2 resulted in generating a lot of OH· radicals. Therefore, 2,4,6-TCPwas destroyed to formic acid and oxalic acid by ozone and OH· radicals together. With the inhibition of OH· radicals, ozone molecule firstly destroyed 2,4,6-TCPto form chlorinated quinone, which was subsequently oxidized to formic acid and oxalic acid. Two reaction pathways of the degradation of 2,4,6-TCPby ozone and O3/OH· are proposed.
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