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研究报告

王枫亮,陈平,苏海英,王盈霏,马京帅,姚琨,李富华,刘国光,吕文英.水体中几种无机离子对硝酸根敏化甲芬那酸光降解影响研究[J].环境科学学报,2016,36(8):2859-2868

Effects of inorganic ions on the nitrate photosensitized transformation of mefenamic acid in aqueous solution

摘要：以中压汞灯为光源，研究环境浓度范围内硝酸根对甲芬那酸（MEF）光降解的影响机制.结果表明，甲芬那酸在不同浓度硝酸根溶液中的光解反应符合准一级动力学规律，其降解速率常数随硝酸根离子浓度增大而增大，当硝酸根离子浓度由0增至1 mmol·L^-1时其速率常数由0.00627 min^-1增至0.0232 min^-1；以异丙醇为分子探针检测到羟基自由基存在于MEF光解过程中；光解过程中产生亚硝酸根，其浓度随着反应的进行而不断增大；碱性水环境对硝酸根敏化甲芬那酸的光解反应有利；碳酸盐、氯离子、三价铁对硝酸根敏化甲芬那酸光解产生抑制作用.采用UPLC/MS/MS对硝酸根敏化MEF光降解产物进行鉴定，并提出3条可能的光解路径.毒性研究表明，在硝酸根敏化甲芬那酸光降解过程中，生成了具有较甲芬那酸而言更高风险的中间产物.

Abstract：The mechanism of mefenamic acid (MEF) photodegradation in aqueous media was investigated in the presence of nitrate under UV irradiation. The results demonstrate that the photodegradation of MEF followed pseudo-first-order kinetics. The photolysis of MEF was enhanced, and the MEF photolysis rate significantly increased, from 0.00627 min^-1 to 0.0232 min^-1 as the nitrate was increased from 0 mmol·L^-1 to 1 mmol·L^-1. Hydroxyl radicals were detected in the photolysis process through using isopropanol as a molecular probe. During the photolysis process, nitrite was generated as the increasing reaction time. Alkalinity increased the photodegradation of MEF in the presence of nitrate ions while carbonate, Cl^-, Fe³⁺ had inhibitory effects. Photoproducts of MEF were identified using UPLC/MS/MS, and three possible pathways were proposed. The toxicity of the phototransformation products was evaluated using the Microtox test, which revealed that the photoproducts were more toxic than mefenamic acid.