摘要
光化学降解是表层水体中抗生素类污染物的重要消减方式.研究了水中代表性唑烷酮类抗生素利奈唑酮的光降解动力学、影响因素与转化产物.模拟日光(λ>290nm)照射下,利奈唑酮的光解遵循准一级反应动力学,纯水中表观光解量子产率为0.834±0.054;与纯水中相比,淡水、海水中光解较慢,这归因于水中常见溶解性物质的影响.pH,Cl–和海水盐度对光解动力学无显著影响(P>0.05),但腐殖酸、NO3–和Fe(III)通过光掩蔽等效应显著抑制其光降解猝灭实验表明,模拟日光和UV-vis(λ>200nm)照射下,利奈唑酮发生了直接光解及1O2参与的自敏化光解,表现为光解速率常数与初始浓度呈负相关.两种光源照射下,主要光解产物和途径均有差别,UV-vis光照下主要发生了脱氟和光致水解,而在模拟日光照射下发生了吗啉环脱氢等反应.
Photochemical degradation is a central factor in determining the fate of antibiotic micropollutants in surface waters. In this study, the photodegradation kinetics, influencing factors and transformation products of linezolid, a representative oxazolidinone antibiotic, were investigated. Under simulated sunlight irradiation （λ〉290 nm）, the photodegradation followed the pseudo-first-order kinetics with an apparent quantum yield of 0.834±0.054 in pure water. The rates of linezolid photodegradation were slower in freshwater or seawater than in pure water, which was attributed to the effects of the ubiquitous aqueous dissolved matter on the photodegradation, pH, C1- and seawater salinity did not affect the photodegradation kinetics （P〉0.05）, while humic acid, NO~ and Fe（III） acted mainly as radiation filters and inhibited the photodegradation （P~〈0.05）. Under simulated sunlight as well as UV-vis （2〉200 nm） irradiation, scavenging experiments revealed that linezolid underwent direct photolysis and self-sensitized photodegradation via tO2, which resulted in a negative correlation between the photolysis rate constants and the initial concentrations. The main photodegradation products and pathways varied under irradiation of different light sources. Linezolid mainly underwent defluorination and photoinduced hydrolysis under UV-vis irradiation, whereas morpholine-dehydrogen was primary under simulated sunlight.
出处
《科学通报》
EI
CAS
CSCD
北大核心
2012年第26期2469-2474,共6页
Chinese Science Bulletin
基金
国家自然科学基金(21007013)
近岸海域生态环境重点实验室开放基金(201007)资助
关键词
利奈唑酮
光降解
影响因素
反应类型
产物
linezolid, photodegradation, influencing factors, reactive types, photoproducts
