Enhanced ozonation of dichloroacetic acid in aqueous solution using
nanometer ZnO powders |
| |
Authors: | Xu Zhai Zhonglin Chen Shuqing Zhao He Wang and Lei Yang |
| |
Institution: | 1. State Key Laboratory of Urban Water Resource and Environment,School of Municipal and Environmental Engineering,Harbin Institute of Technology,Harbin 150090,China 2. State Key Laboratory of Urban Water Resource and Environment,School of Municipal and Environmental Engineering,Harbin Institute of Technology,Harbin 150090,China;Forestry Institute,Northeast Forestry University,Harbin 150090,China |
| |
Abstract: | Nanometer zinc oxide (ZnO) powders were used as a catalyst to enhance the ozonation for the degradation of dichloroacetic acid
(DCAA) in aqueous solution. The batch experiments were carried out to investigate the e ects of key factors such as catalyst dosage,
ozone dosage, solution pH and tert-butyl alcohol (t-BuOH) on the degradation e ciency of DCAA. Density functional theory (DFT)
was adopted to explore the mechanism of generating hydroxyl radical (.OH) on the ZnO surface. The results showed that adsorption
and ozonation processes were not e ective for DCAA removal, and the addition of ZnO catalyst improved the degradation e ciency of
DCAA during ozonation, which caused an increase of 22.8% for DCAA decomposition compared to the case of ozonation alone after 25
min. Under the same experimental conditions, the DCAA decomposition was enhanced by increasing catalyst dosage from 100 to 500
mg/L and ozone dosage from 0.83 to 3.2 mg/L. The catalytic ozonation process is more pronounced than the ozonation process alone at
pH 3.93, 6.88, and 10. With increasing the concentration of t-BuOH from 10 to 200 mg/L, the degradation of DCAA was significantly
inhibited in the process of catalytic ozonation, indicating that ZnO catalytic ozonation followed .OH reaction mechanism. Based on
the experimental results and DFT analysis, it is deduced that the generation of .OH on the ZnO surface is ascribed to the adsorption of
molecule ozone followed by the interaction of adsorbed ozone with active sites of the catalyst surface. It is also concluded that ZnO
may be an e ective catalyst for DCAA removal, which could promote the formation of .OH derived from the catalytic decomposition
of ozone. |
| |
Keywords: | dichloroacetic acid catalytic ozonation density functional theory hydroxyl radical |
本文献已被 CNKI 万方数据 ScienceDirect PubMed 等数据库收录! |
| 点击此处可从《环境科学学报(英文版)》浏览原始摘要信息 |
| 点击此处可从《环境科学学报(英文版)》下载免费的PDF全文 |
|