黄腐酸对17α-乙炔基雌二醇光降解的影响

Influence of Fulvic Acid on the Photodegradation of 17α-ethynylestradiol

以黄腐酸(FA)为溶解性有机质代表物,探讨了FA对水中17α-乙炔基雌二醇(EE2)光降解过程的影响及其机制。结果表明:EE2在纯水和FA溶液中的光降解过程均服从准一级动力学规律。与纯水溶液相比(0.0157h-1),EE2在FA溶液(5.0mgC/L)中的光降解速率显著增大(P<0.05),其增幅约434%。但是,随FA浓度增大,EE2光降解速率增幅不断减小,当FA浓度高于20.0mgC/L时,EE2光降解速率趋于稳定。活性物质淬灭实验表明,光生羟基(HO·)和三线态物种是导致FA溶液中EE2发生快速光降解的主要原因。研究结果可为水生生态系统中类固醇雌激素的归趋及风险评价提供依据。

In this study,the influence of dissolved organic matter on 17α-ethynylestradiol(EE2)photodegradation in waters was studied by selecting fulvic acid(FA)as a representative.The mechanisms of FA on EE2 photodegradation was also indentified.The results showed that both the photodegradation of EE2 in pure water and FA solution obeyed the pesudo first-order kinetics.Compared to EE2 photodegradation in pure water(0.0157 h-1),the photodegradation rate of EE2 in FA solution(5.0 mgC/L)was hugely enhanced(P<0.05),with an extent about 434%.With the FA concentration increasing,the enhancement of EE2 photodegradation rate decreased continuously.When the concentration of FA was over the threshhold of 20.0 mgC/L,EE2 photodegradation rate tended to be stable.The reactive species quenching experiments showed that the photogenerated hydroxyl groups(HO·)and triplet-state excited species were the main contributors to the rapid photodegradation of EE2 in FA solutions.The results derived from this study could provide a basis for the fate and risk assessment of steroid estrogens in aquatic ecosystems.