Zeng Xiaolan, Sun Xiaozi, Meng Yu, Yu Ningning, Liu Jing
College of Chemistry and Chemical Engineering, Xinyang Normal University, Henan Xinyang, 464000 People's Republic of China.
Henan Key Laboratory for Synergistic Prevention of Water and Soil Environmental Pollution, Xinyang Normal University, Henan Xinyang, 464000 People's Republic of China.
Water Air Soil Pollut. 2021;232(10):410. doi: 10.1007/s11270-021-05351-5. Epub 2021 Oct 1.
Sulfonamides (SAs) including sulfamethoxypyridazine (SMP) are regarded as a new type of persistent pollutant at present due to their abuse. In this work, the direct photodegradation behavior of 11 SAs under simulated sunlight was first investigated, and the results indicated that the direct photolysis of SMP is the slowest among these SAs. Then the oxidation degradation of SMP in UV/Co(II)/peroxymonosulfate (PMS) system was systematically explored. Up to 95.2% removal of 0.071 mM SMP was observed after 20 min of reaction under the optimal condition with a molar ratio of 1:150:5 between SMP, PMS, and Co(II). The effects of some coexisting anions on degradation of SMP were investigated. It was found that Cl and high concentrations of CO and HCO have a significant inhibitory effect, while HPO has only a slight positive effect. Radical scavenger experiments indicated that hydroxyl radicals (HO) are prevailing active species responsible for SMP removal in UV/Co(II)/PMS system. The degradation of SMP in UV/Co(II)/PMS system was accomplished mainly by hydroxylation of the aromatic ring, extrusion of SO, oxidation of NH group, and N - S bond cleavage. Eight intermediates for SMP degradation were identified, and their toxicities to aquatic organisms were predicted by using the ECOSAR program based on the structure - activity relationships (SARs), which suggested that the chronic toxicities of SMP and its degradation intermediates are more significant than their acute toxicities. The present research indicates that UV/Co(II)/PMS system is applicable for SMP degradation in aqueous solutions and may be helpful to understand the transformation behavior of SAs.
The online version contains supplementary material available at 10.1007/s11270-021-05351-5.
包括磺胺甲氧嗪（SMP）在内的磺胺类药物（SAs）由于滥用，目前被视为一种新型持久性污染物。在本研究中，首次研究了11种磺胺类药物在模拟阳光下的直接光降解行为，结果表明，磺胺甲氧嗪的直接光解在这些磺胺类药物中是最慢的。然后系统地研究了磺胺甲氧嗪在紫外/钴（II）/过一硫酸盐（PMS）体系中的氧化降解。在最佳条件下，当磺胺甲氧嗪、过一硫酸盐和钴（II）的摩尔比为1:150:5时，反应20分钟后，0.071 mM磺胺甲氧嗪的去除率高达95.2%。研究了一些共存阴离子对磺胺甲氧嗪降解的影响。发现Cl以及高浓度的CO₃²⁻和HCO₃⁻具有显著的抑制作用，而HPO₄²⁻只有轻微的促进作用。自由基清除实验表明，羟基自由基（·OH）是紫外/钴（II）/过一硫酸盐体系中去除磺胺甲氧嗪的主要活性物种。磺胺甲氧嗪在紫外/钴（II）/过一硫酸盐体系中的降解主要通过芳环羟基化、SO₂脱出、NH基团氧化和N-S键断裂来实现。鉴定出了8种磺胺甲氧嗪降解的中间产物，并基于结构-活性关系（SARs）使用ECOSAR程序预测了它们对水生生物的毒性，这表明磺胺甲氧嗪及其降解中间产物的慢性毒性比急性毒性更显著。本研究表明，紫外/钴（II）/过一硫酸盐体系适用于水溶液中磺胺甲氧嗪的降解，可能有助于理解磺胺类药物的转化行为。
在线版本包含可在10.1007/s11270-021-05351-5获取的补充材料。
