Photocatalytic degradation kinetics and mechanism of environmental pharmaceuticals in aqueous suspension of TiO2: a case of beta-blockers.
Photocatalytic degradation kinetics and mechanism of environmental pharmaceuticals in aqueous suspension of TiO2: a case of beta-blockers.
复制标题
DOI：
10.1016/j.jhazmat.2010.03.079
复制
发表时间：
2010-07
影响因子：
13.6
通讯作者：
Hai Yang;T. An;Guiying Li;Weihua Song;W. J. Cooper;Haiying Luo;Xin-chao Guo
中科院分区：
文献类型：
--
作者：
Hai Yang;T. An;Guiying Li;Weihua Song;W. J. Cooper;Haiying Luo;Xin-chao Guo
研究了三种磺胺类药物在TiO 2水悬浮液中的光催化降解动力学。根据Langmuir-Hinshelwood（L-H）模型，这三种化合物的消失遵循伪一级动力学。考察了催化剂用量、初始pH值、底物初始浓度等因素对光催化降解率的影响。磺胺类药物的降解主要是由于TiO 2表面反应的影响，而活性氧（ROS）的进一步研究表明，光空穴（h+）和羟基自由基（OH）是磺胺类药物降解的主要原因。硫和氮元素在各种磺胺类药物以及总有机碳（TOC）的命运进行了检查后，其光催化转化。结果表明，3种药物在240 min内均能完全矿化为CO2、H2O和无机离子。这些结果表明，磺胺类药物的光催化转化过程中产生了许多中间产物。基于已鉴定的中间体，提出了磺胺类药物光催化降解的两种可能途径，即羟基化加成和光空穴攻击下磺胺上的S-N键断裂。
The photocatalytic degradation kinetics of three sulfa pharmaceuticals has been investigated in TiO2aqueous suspension. The disappearance of these three compounds follows a pseudo-first-order kinetics according to the Langmuir–Hinshelwood (L–H) model. The effects of catalyst amount, initial pH value, and initial concentration of each substrate on the photocatalytic degradation rates were measured in detail. It was observed that the surface reaction on TiO2played an important role in the degradation of sulfa pharmaceuticals, and the further study of reactive oxygen species (ROSs) indicated that both photohole (h+) and especial hydroxyl radical (OH), were responsible for the major degradation of sulfa pharmaceuticals. The fates of the sulfur and nitrogen elements in various sulfa pharmaceuticals as well as total organic carbon (TOC) were examined following their photocatalytic transformation. The data showed that all three pharmaceuticals could be completely mineralized into CO2, H2O and inorganic ions within 240min. These results indicated that many intermediates were produced during the photocatalytic transformation of sulfa pharmaceuticals process. Based on the identified intermediates, two tentative degradation pathways for the photocatalytic degradation of sulfa pharmaceuticals were proposed, for example hydroxylation addition to parent pharmaceuticals and the cleavage of S–N bond from the sulfaniline attacked by photohole.