紫外/一氯胺高级氧化工艺降解萘丁美酮的动力学、降解路径、毒性变化和消毒副产物生成

Kinetics,Degradation Pathways,Toxicity Changes,and Disinfection By-Product Formation in Degradation of Nabumetone by UV/Monochloramine Advanced Oxidation Processes

紫外活化氯胺高级氧化工艺对降解有机微污染物具有潜在应用价值.为探究紫外/一氯胺(UV/NH_(2)Cl)工艺对水中非甾体抗炎药的去除性能,选用萘丁美酮(nabumetone,NMT)为降解对象,比较UV光解、NH_(2)Cl氧化和UV/NH_(2)Cl这3种手段对NMT的降解性能,考察NH_(2)Cl投加量、pH、Cl^(−)、HCO_(3)^(−)和天然有机物(natural organic matters,NOM)对UV/NH_(2)Cl降解NMT的影响,结合量子化学计算和UPLC-HRMS检测结果探究NMT的降解路径并预测毒性变化,最后分析消毒副产物的生成情况.结果表明:①UV/NH_(2)Cl体系内NMT的降解过程符合拟一级反应动力学方程,在温度25℃、NMT初始浓度5μmol/L、NH_(2)Cl投加量50μmol/L的条件下,反应150 s后NMT的降解效率可达88.81%.②增加NH_(2)Cl投加量可促进NMT降解,pH在5.5~8.5范围内对NMT降解速率无明显变化,Cl−、HCO_(3)−和NOM对NMT的降解具有抑制作用.③基于UPLC-HRMS共鉴定出10种降解产物,NMT降解过程主要涉及羟基化、亚硝基化和去甲基化等反应,TEST软件预测表明,降解产物的急性毒性和发育毒性比NMT母体更高.④气相色谱检测结果显示,UV/NH_(2)Cl促进了NMT降解过程中消毒副产物的产生.研究显示,UV/NH_(2)Cl高级氧化工艺对水中NMT具有良好的降解效能,其降解产物可能存在更高的急性毒性和发育毒性,后续需进一步探究.

UV-activated chloramine advanced oxidation process has potential application value in the degradation organic micropollutants.In order to investigate the removal performance of non-steroidal anti-inflammatory drugs in water by ultraviolet/monochloramine(UV/NH_(2)Cl)system,the degradation of nabumetone(NMT)by UV photolysis,NH_(2)Cl oxidation and UV/NH_(2)Cl was compared.The influence of various factors on the degradation of NMT by UV/NH_(2)Cl was investigated.The degradation pathways of NMT was investigated and the toxicity changes were predicted by combining the quantum chemical calculation and the detection results of UPLC-HRMS.Finally,the generation of disinfection by-products was analyzed.The results show that:(1)The degradation of NMT in UV/NH_(2)Cl system conforms to the pseudo-first-order reaction kinetics equation.Under the conditions of 25℃,the initial concentration of NMT is 5μmol/L,and the dosage of NH_(2)Cl is 50μmol/L,the degradation efficiency of NMT could reach 88.81%after 150 s of reaction.(2)Increasing the dose of NH_(2)Cl can promote the degradation of NMT,and there is no significant change in the degradation rate of NMT in the range of pH 5.5-8.5.Cl^(−),HCO_(3)^(−)and natural organic matter inhibit the degradation of NMT.(3)A total of 10 degradation products were identified based on UPLC-HRMS,and the degradation process of NMT mainly involved hydroxylation,nitrosation and demethylation.The TEST software predicted that,The acute and developmental toxicity of the degradation products were higher than that of the NMT.(4)Gas chromatography analysis results showed that UV/NH_(2)Cl promoted the generation of disinfection byproducts during the degradation of NMT.The results of this study show that UV/NH_(2)Cl advanced oxidation process has good degradation efficiency for NMT in water,and its degradation products may have higher acute and developmental toxicity,which needs further investigation.