亚硫酸盐/过氧乙酸新型体系对水中碘代药物的降解效能与机制

Iodinated pharmaceuticals are widely used and emerging as a new type of environmental pollutants. Sulfate radical-based advanced oxidation processes can achieve significant removal of iodinated pharmaceuticals. Activating persulfate has been commonly used, requiring high energy consumption or addition of transition metals. This project takes sulfite as the sulfate radical precursor and develops a novel advanced oxidation process by the combination of sulfite and peracetic acid. This process will not only significantly promote the production of sulfate radical and degrade iodinated pharmaceuticals, but also effectively overcome the problem of adding transition metals and avoid secondary pollution. The following work will be conducted. Firstly, the abatement efficiency and degradation kinetics of iodinated pharmaceuticals by sulfite/peracetic acid process will be investigated. The influence of various water quality parameters and gas atmosphere of the reaction system on the abatement efficiency and kinetics of iodinated pharmaceuticals will be explored. Secondly, major reactive radicals produced in sulfite/peracetic acid process will be analyzed and the formation mechanism of sulfate radical will then be clarified. Finally, the degradation products and pathways will be studied and the transformation of iodine species (iodide, reactive iodine and iodate) will then be illuminated with respect to the deiodination of iodinated pharmaceuticals. Implementation of this project will provide theoretical basis and technological support to the rapid abatement of iodinated pharmaceuticals by sulfate radical-based advanced oxidation process.

碘代药物应用广泛，逐渐成为一类新型环境污染物，基于硫酸根自由基的高级氧化技术对碘代药物有很好的去除效果，目前多采用活化过硫酸盐的方法，但存在能耗高、需投加过渡金属等问题。本项目拟采用活化亚硫酸盐的方法，构建亚硫酸盐/过氧乙酸新型高级氧化体系，既可显著促进硫酸根自由基的产生，强化碘代药物的降解，又能有效克服需要投加过渡金属的问题，避免二次污染。主要开展以下工作：首先，研究亚硫酸盐/过氧乙酸体系对碘代药物的降解效能与动力学，探讨不同水质参数和反应体系气体氛围对碘代药物降解效能与动力学的影响；其次，分析亚硫酸盐/过氧乙酸体系产生的主要活性自由基，阐明硫酸根自由基的生成及作用规律；最后，研究碘代药物的降解产物和降解路径，基于脱碘情况，揭示碘组分(碘离子、活性碘和碘酸盐)的转化规律。本项目的实施预期将为基于硫酸根自由基的高级氧化技术快速降解碘代药物提供理论依据和技术支撑。

本研究成功构建了亚硫酸盐/过氧乙酸新型高级氧化体系，系统考察了亚硫酸盐/过氧乙酸体系对水中碘代药物的降解效能与机制，识别体系降解碘代药物效能的主要因素，评价该体系降解多种碘代药物的适用性，明确碘代药物的降解机制。结果表明：在中性条件下亚硫酸盐/过氧乙酸体系对碘海醇、碘普罗胺、泛影酸钠和甲状腺素的降解效率达到100%。通过EPR和荧光光谱分析，证实了体系中活性自由基(SO3•−、HO•)的产生；基于自由基定量实验，得出亚硫酸盐/过氧乙酸体系中SO4•−和HO•的稳态浓度分别为~6.5μM和~3.6μM；自由基抑制结果表明对SO4•−和HO•对降解碘海醇的贡献率分别为60.0%和20.0%。由于过氧乙酸作为有机酸催化剂和强氧化剂的特性，亚硫酸盐和过氧乙酸比例对亚硫酸盐/过氧乙酸体系产生的主要活性自由基存在显著的影响。随后，分析了水质参数对碘海醇降解效能的贡献，溶液pH值、溶解氧、水中阴离子和腐殖酸对碘海醇降解效能有显著的影响。最后，基于产物分析，阐明了碘海醇的降解路径和降解机制。亚硫酸盐/过氧乙酸体系能够高效产生硫酸根自由基，实现碘代药物的快速氧化降解，具有实际应用潜力。