天然水体腐殖质对双酚A光降解影响的研究

以中压汞灯模拟太阳光光源，研究了双酚A(BPA)在水体腐殖质中的光降解过程，探讨了不同来源的腐殖质、腐殖质浓度、BPA初始浓度、溶解氧等因素对BPA光解速率的影响，实验结果表明，BPA在纯水体系中直接光解很慢，但在腐殖质溶液中光解迅速，符合拟一级动力学反应，改变BPA初始浓度对BPA光解速率的影响不明显，增大溶解氧浓度会抑制BPA光解，通过活性氧分子探针鉴定了腐殖质吸收光辐射产生的羟基与单线态氧，利用GC-MS鉴定了双酚A在Nordic湖富里酸(NOFA)中的光敏化降解产物，推测出BPA敏化降解的可能历程为能量转移导致的直接光解、羟基加成和羟基氧化。

Study on the effect of natural aquatic humic substances on the photodegradation of bisphenol A

The photochemical degradation of BPA was studied in the presence of natural humic substances from different sources under simulated solar irradiation. BPA underwent insignificant direct photolysis in deioned water, but it could take place the rapid photosensitized degradation in four humic substances solutions via pseudo-first-order reaction. The photodegradation rate of BPA was insensitive for the variation of initial BPA concentration, and was inhibited in aerated solution compared with the deoxygenated medium. The reactive oxygen species (.OH and 1O_2) produced from excitation of humic substances under irradiation was determined from the quenching kinetic experiment by molecular probe. Five main intermediate photoproducts of BPA in NOFA were tentatively identified by GC-MS. Based on the analysis of the photoproducts formation, the possible phototransformation pathways of BPA were proposed, involving the hydroxyl radical addition and oxidation, as well as the direct photolysis due to the energy transfer from the triplet state 3HS* to BPA molecules.