State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, PR China.
J Hazard Mater. 2012 Nov 15;239-240:340-7. doi: 10.1016/j.jhazmat.2012.09.005. Epub 2012 Sep 11.
Atenolol (ATL) is a photostable and hydrolysis resistant beta-blocker and has been frequently detected in natural water. In this study, mechanism on aquatic photodegradation of ATL was investigated with an emphasis on the role of dissolved organic matters (DOMs) as well as other natural water compositions (nitrate, bicarbonate and ferric ions). Significant acceleration of photodegradtion of ATL was observed in the presence of each DOMs added, namely Suwannee River Fulvic Acid (SRFA), Suwannee River Humic Acid (SRHA), Nordic Lake Fulvic Acid (NOFA) and Nordic Lake Humic Acid (NOHA). Hydroxyl radical (•OH) was determined as the main reactive species in this process, instead of singlet oxygen or excited triplet of DOM. Addition of these four DOMs all inhibited photodegradation of ATL in nitrate solutions through reducing nitrated-derived •OH and screening photons absorbed by nitrate. No loss of ATL was detected in bicarbonate solution with or without DOMs. Bicarbonate exhibited a scavenger of •OH derived from DOMs. However, in the presence of iron species, photodegradation of ATL was significantly enhanced by the addition of each DOM, due to the high yield of •OH in the photoprocess of Fe(III)-DOM complex. The photoproducts distribution of ATL demonstrated that SRFA promote the hydroxylation on aromatic ring in the presence of nitrate and reduce the ketone moiety to alcohol in the system of ferric ions. Our findings indicate that DOMs should be considered in aquatic photoprocesses of organic pollutants induced by themselves as well as other coexisting photoactive water compositions.
阿替洛尔（ATL）是一种光稳定且水解稳定的β受体阻滞剂，经常在天然水中被检测到。在这项研究中，我们研究了 ATL 在水中的光降解机制，重点探讨了溶解有机物（DOM）以及其他天然水成分（硝酸盐、碳酸氢盐和铁离子）的作用。当添加每种 DOM（即苏万尼河富里酸（SRFA）、苏万尼河腐殖酸（SRHA）、北欧湖富里酸（NOFA）和北欧湖腐殖酸（NOHA））时，ATL 的光降解明显加速。在这个过程中，确定了羟基自由基（•OH）是主要的反应性物质，而不是 DOM 的单线态氧或激发三重态。添加这四种 DOM 都会通过减少硝化物衍生的•OH 和屏蔽硝酸盐吸收的光子来抑制硝酸盐溶液中 ATL 的光降解。无论是否添加 DOM，在碳酸氢盐溶液中都未检测到 ATL 的损失。碳酸氢盐表现为 DOM 衍生的•OH 的清除剂。然而，在铁物种存在的情况下，由于 Fe（III）-DOM 络合物光过程中•OH 的高产量，添加每种 DOM 都会显著增强 ATL 的光降解。ATL 的光降解产物分布表明，在硝酸盐存在的情况下，SRFA 促进芳香环的羟化，并在铁离子体系中减少酮部分为醇。我们的研究结果表明，在由自身以及其他共存的光活性水成分引起的有机污染物水相光过程中，应考虑 DOM。
