Liu Zi-Qi, Qiu Fu-Guo, Lai Man-Ting, Li Jin, Dong Hui-Yu, Qiang Zhi-Min
College of Environmental Science and Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Huan Jing Ke Xue. 2021 Mar 8;42(3):1443-1450. doi: 10.13227/j.hjkx.202007274.
Based on the formation of free radical-hydrated electrons by the activation of sulfite (SO), the UV/SO process is an advanced reduction process that can reduce pollutants. This study investigated the degradation kinetics, mechanism, influencing factors, and degradation pathways of sodium diatrizoate (DTZ), an iodinated contrasting media, during the UV/SO process. The degradation kinetics of DTZ were well fitted by the pseudo-first-order model, the degradation rate of which was higher than that of UV only and UV/H O. The degradation rate of DTZ during the UV/SO process was positively correlated with the initial SO concentration. Weakly alkaline and alkaline conditions promoted the degradation of DTZ, while organic matter inhibited degradation during the UV/SO process. The degradation mechanism included direct photolysis and free radical attack, whereby free radical attack played a more important role than direct photolysis. Sulfite radicals dominated DTZ degradation efficiency, and hydrated electrons controlled the deiodination efficiency. The degradation pathways of DTZ during the UV/SO process included substitution, decarboxylation-hydroxylation, and amide bond cleavage.
基于亚硫酸盐（SO）活化形成自由基水合电子，UV/SO工艺是一种可降解污染物的高级还原工艺。本研究考察了碘化造影剂泛影酸钠（DTZ）在UV/SO工艺中的降解动力学、机理、影响因素及降解途径。DTZ的降解动力学符合准一级模型，其降解速率高于单独UV和UV/H₂O工艺。UV/SO工艺中DTZ的降解速率与初始SO浓度呈正相关。弱碱性和碱性条件促进DTZ的降解，而有机物在UV/SO工艺中抑制降解。降解机理包括直接光解和自由基攻击，其中自由基攻击比直接光解起更重要的作用。亚硫酸根自由基主导DTZ的降解效率，水合电子控制脱碘效率。UV/SO工艺中DTZ的降解途径包括取代、脱羧-羟基化和酰胺键断裂。
