Department of Chemical Engineering and Physical Chemistry, Area of Chemical Engineering, Faculty of Sciences, University of Extremadura, Avda. de Elvas, s/n, 06006, Badajoz, Spain.
Department of Chemical Engineering and Physical Chemistry, Area of Chemical Engineering, Faculty of Sciences, University of Extremadura, Avda. de Elvas, s/n, 06006, Badajoz, Spain.
J Environ Manage. 2020 May 1;261:110156. doi: 10.1016/j.jenvman.2020.110156. Epub 2020 Jan 31.
The degradation of four representative neonicotinoids, namely Thiamethoxam, Imidacloprid, Acetamiprid and Thiacloprid, was carried out by the sequential association of different advanced oxidation processes, including Ozonation, Electro-chemical Oxidation, Ultrasound, Ultraviolet radiation, and their different possible associations. There are no published papers in the literature on the removal of this type of insecticides through these associated oxidation processes. Single oxidation processes did not achieve total pollutants removal in less than 3 h (only UV radiation treatment obtain a total removal of Thiamethoxan in 150 min, but with mineralization below 15% TOC). For double sequential processes, Electro-oxidation-Ozone treatment obtains a total removal of Imidacloprid in 120 min and an increase of mineralization to 50% TOC. Three or four sequential processes are recommended to improve degradation and mineralization rates in a significant way, Electro-oxidation-Ozone-UV treatment obtains a total removal of Thiamethoxan in 80 min with mineralization over 75% TOC. These results confirm important synergistic effects which were quantified. The global trend indicates that Thiamethoxam is the most oxidizable neonicotinoid, whereas Acetamiprid is the most recalcitrant compound. The degradation rate of each neonicotinoid followed pseudo-first-order kinetics and the different oxidation pathways were also quantified from a kinetic point of view.
四种代表性新烟碱类杀虫剂（噻虫嗪、吡虫啉、噻虫胺和噻虫砜）的降解是通过不同高级氧化工艺的顺序联合进行的，包括臭氧化、电化学氧化、超声、紫外辐射及其不同可能的联合。在文献中，没有关于通过这些联合氧化过程去除这类杀虫剂的报道。单一氧化工艺在不到 3 小时内无法实现污染物的完全去除（只有 UV 辐射处理在 150 分钟内获得了噻虫嗪的完全去除，但总有机碳（TOC）的矿化率低于 15%）。对于双序连续工艺，电氧化-臭氧处理可在 120 分钟内实现吡虫啉的完全去除，并将矿化率提高到 50% TOC。推荐采用三或四序连续工艺以显著提高降解和矿化速率，电氧化-臭氧-紫外处理可在 80 分钟内完全去除噻虫嗪，TOC 的矿化率超过 75%。这些结果证实了重要的协同效应，并进行了定量分析。总体趋势表明，噻虫嗪是最易氧化的新烟碱类杀虫剂，而噻虫胺是最难降解的化合物。从动力学角度来看，每种新烟碱类杀虫剂的降解速率均遵循准一级动力学，并且还量化了不同的氧化途径。
