紫外/亚硫酸钠体系对2,4,6-三溴酚的脱溴效果及机理

Debromination effect and mechanism of 2,4,6-tribromophenol by UV/sodium sulfite system

研究了紫外/亚硫酸钠(UV/SO32-)体系对2,4,6-三溴酚(2,4,6-TBP)的脱溴效果及影响因素,分析了还原体系2,4,6-TBP的脱溴过程、降解机理及降解路径。结果表明:UV/SO32-还原体系对2,4,6-TBP的降解效果明显高于单独UV体系;亚硫酸钠浓度、pH与反应温度均对还原体系目标污染物的降解影响显著。随着亚硫酸钠浓度升高、pH上升及反应温度提高,UV/SO32-体系2,4,6-TBP的降解效果逐渐增加。准一级动力学方程可描述不同亚硫酸钠浓度与反应温度时还原体系对目标污染物的降解过程。水合电子捕获剂的添加可有效抑制2,4,6-TBP的脱溴反应;UV/SO32-体系污染物还原降解速率与溴离子产生率均高于单独UV体系。还原体系中2,4,6-TBP在水合电子作用下逐级脱溴降解为低毒性物质。

The debromination effect and influencing factors of 2,4,6-TBP in UV/SO32-system were examined,and the debromination process,degradation mechanism and degradation pathway of 2,4,6-TBP in reduction system were analyzed.Results showed that:the degradation effect of UV/SO32-reduction system on 2,4,6-TBP was significantly higher than that of UV system alone.Na2SO3 concentration,pH and reaction temperature had significant effects on the degradation effect of reduction system.With the increase of Na2SO3 concentration,pH and reaction temperature,the degradation effect of UV/SO32-system 2,4,6-TBP increased gradually.The quasi-first-order kinetic equation could describe the degradation process of the target pollutant in the reduction system at different Na2SO3 concentrations and reaction temperatures.The addition of hydrated electron capture agent could effectively inhibit the debromination reaction of 2,4,6-TBP.The reduction rate and bromide ion yield of the pollutants in the UV/SO32-system were higher than that of the UV system alone.2,4,6-TBP was degraded into low toxicity substances by hydration electrons in the reduction system.