Photodecomposition of 4-chlorophenol by reactive oxygen species in UV/air system
Photodecomposition of 4-chlorophenol by reactive oxygen species in UV/air system
复制标题
紫外/空气系统中活性氧对 4-氯苯酚的光分解
DOI：
10.1016/j.jhazmat.2010.11.023
复制
发表时间：
2011-02-15
影响因子：
13.6
通讯作者：
Su, Yaling
中科院分区：
文献类型：
--
作者：
Du, Yingxun;Fu, Q. Shiang;Su, Yaling
本文研究了4-氯苯酚(4-CP)在紫外光照射下的光降解，重点研究了活性氧物种(ROS)对4-CP的光降解作用。4-CP在UV/空气体系中比在UV/N-2体系中降解更快、更彻底。在UV/空气体系中，(OH)-O-中心点清除剂叔丁醇的加入对4-CP的降解有明显的抑制作用。在叔丁醇存在下，UV/空气体系中4-CP的降解和中间体的形成趋势与UV/N-2体系非常相似。在UV/空气体系中，4-CP的降解有两条途径，一条是通过吸收光子直接光解，另一条是通过(OH)-O-心点氧化。根据表观动力学常数，直接光解和(OH)-O-中心点氧化对4-CP分解的贡献率分别为17.2%和82.8%。在紫外光/空气体系中，过氧化氢可通过光解生成(OH)-O-心点。结果表明，溶解氧、激发态有机物和氢离子都是过氧化氢形成所必需的。在实验的基础上提出了过氧化氢的生成机理。(C)2010爱思唯尔B.V.保留所有权利。
In this article, the photo-degradation of 4-chlorophenol (4-CP) under UV irradiation was studied with focus on the photodecomposition of 4-CP by reactive oxygen species (ROS). 4-CP underwent much faster and more complete degradation in UV/air system than in UV/N-2 system. In UV/air system, the addition of t-butanol, a well-known (OH)-O-center dot scavenger, significantly impeded the degradation of 4-CP. In the presence of t-butanol, the tendencies for the degradation of 4-CP and the formation of intermediates in UV/air system were very similar to those in UV/N-2 system. In UV/air system, 4-CP was degraded by two pathways, direct photolysis by absorbing the photons and the oxidation via (OH)-O-center dot. The contribution of direct photolysis and the oxidation via (OH)-O-center dot to 4-CP decomposition were 17.2% and 82.8%, respectively based on the apparent kinetic constants. Hydrogen peroxide, which could produce (OH)-O-center dot through photolysis, was formed in UV/air system. It was shown that dissolved oxygen, organic matter in excited state and hydrogen ion are all necessary for the formation of hydrogen peroxide. The formation mechanism of H2O2 was proposed based on experimental evidence. (c) 2010 Elsevier B.V. All rights reserved.