Transformation and removal of imidacloprid mediated by silver ferrite nanoparticle facilitated peroxymonosulfate activation in water: Reaction rates, products, and pathways
Transformation and removal of imidacloprid mediated by silver ferrite nanoparticle facilitated peroxymonosulfate activation in water: Reaction rates, products, and pathways
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铁氧体银纳米粒子介导的吡虫啉的转化和去除促进水中过一硫酸盐的活化：反应速率、产物和途径
DOI：
10.1016/j.envpol.2020.115438
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发表时间：
2020
影响因子：
8.9
通讯作者：
Liang Mao
中科院分区：
文献类型：
--
作者：
Qihui Kan;Kun Lu;Shipeng Dong;Danlei Shen;Qingguo Huang;Yang Tong;Wei Wu;Shixiang Gao;Liang Mao
吡虫啉（IMI）是使用最广泛的有机氯农药之一，其广泛存在使其引起了越来越多的公众关注和科学兴趣。过氧单硫酸盐（PMS）活化法是去除水中有机污染物的一种有效方法。但很少有研究集中在它们的非均相催化性能，特别是银铁氧体纳米粒子（nAgFeO 2）的存在下，对吡虫啉的催化性能。本文采用共沉淀法制备了nAgFeO 2催化剂，并将其用于活化PMS去除吡虫啉（IMI）。结果表明，制备的nAgFeO 2能显著促进PMS对IMI的活化去除，且随着nAgFeO 2用量的增加，IMI的去除符合准一级动力学模型。电子顺磁共振（EPR）和淬灭测试表明，在IMI降解中起主导作用的是单线态氧（1 O2）介导的非自由基途径，而不是羟基自由基（· OH）或硫酸根自由基（SO 4·-）。共鉴定出8种产物，并提出了IMI的降解途径。推测IMI的C-1位的主要位点更容易被· OH攻击，产生（6-氯吡啶-3-基）甲醇）。而IMI的脒氮（2）位更容易被1 O2攻击，然后与· OH反应生成5-羟基吡虫啉。总之，本研究揭示了基于PMS的非自由基氧化过程去除水中农药的机理，拓宽了银铁氧体纳米粒子在废水处理中的应用。
Imidacloprid (IMI) is one of the most extensively used chlorinated organic pesticides and its widespread occurrence makes it attract increased public concern and scientific interest. Peroxymonosulfate (PMS) activation has been widely studied for the elimination of organic pollutants from water. But few studies are focused on their heterogeneous catalytic performance towards imidacloprid especially with the presence of silver ferrite nanoparticles (nAgFeO 2)-based catalysts. Herein, the catalyst, nAgFeO 2, was prepared via a co-precipitation method, and further applied to activate PMS for the removal of imidacloprid (IMI). Our results demonstrated that the prepared nAgFeO 2 significantly promoted the activation of PMS for removing IMI, and the removal of IMI followed a pseudo first-order kinetics model with the corresponding nAgFeO 2 dosage. Electron paramagnetic resonance (EPR) and quenching tests revealed the singlet oxygen (1 O 2)-mediated nonradical pathway, instead of hydroxyl radical (• OH) or sulfate radical (S O 4•−), played the dominant role in the degradation of IMI. Eight products were identified and the degradation pathways of IMI were proposed. It is postulated that the primary site at the C-1 position of IMI was more easily attacked by the• OH yielding (6-chloropyridin-3-yl) methanol). While the site at the amidine nitrogen (2) of IMI was more likely attacked by the 1 O 2, and then reacted with• OH to produce 5-hydroxy imidacloprid. Overall, this study provides insights into the mechanisms of nonradical oxidation processes based on PMS for the elimination of pesticides from water, broadening the application of silver ferrite nanoparticles in wastewater treatment.