水体中磺胺甲恶唑和甲氧苄氨嘧啶的自然光降解

Natural sunlight photodegradation of sulfamethazole and trimethoprim in aquatic environment

实验研究了磺胺甲恶唑和甲氧苄氨嘧啶连续暴露于自然光下72 h,在pH值为4.0、7.0、9.0水体中的光降解行为,同时考察了黑暗条件下对照样品在不同pH条件下的稳定性.实验表明,光强、光照时间、水体pH都直接影响到磺胺甲恶唑的去除率.在自然光照环境下,不同pH溶液中的磺胺甲恶唑均易发生光降解,而黑暗对照样品去除率较小.甲氧苄氨嘧啶则比较稳定,几乎未发生降解,但黑暗对照样品在pH值为4.0和7.0的溶液中,与起始浓度相比,去除率大于10%,这可能主要与该药物在不同pH溶液中的离子形态及光照过程中的温度波动有关.

In this study,natural sunlight photodegradation behavior of sulfamethoxazole and trimethoprim in aqueous solution with pH 4.0,7.0 and 9.0 for consecutive 72 h was studied,while dark controls were used to test the stability of selected drugs under the same condition.The results show that light intensity,illumination time and pH are directly responsible for the loss of sulfamethoxazole.The chemical was susceptible to photodegradation under different pH conditions,but no loss was found for dark controls.Trimethoprim was quite resistant to photodegradation,with hardly any removal.However,over 10% loss of parent compound was observed in aqueous solution with pH 4.0 and 7.0 for dark controls.It is probably related to speciation of TRM as a function of pH,combined with fluctuation of temperature during the photolysis process.