Heterogeneous photocatalytic degradation of diuron on zinc oxide: Influence of surface-dependent adsorption on kinetics,degradation pathway,and toxicity of intermediates

论文摘要

Heterogeneous photocatalytic reaction has been generally applied for degradation of toxic contaminants.Degradations of a compound using the same kind of catalyst that was synthesized differently are commonly found in literature.However,the reported degradation intermediates are normally inconsistent.This issue is especially important for the degradation of toxic compounds because intermediates may be more toxic than their parent compounds and understanding the reason is necessary if appropriate catalysts are to be designed.This work systematically compares the photocatalytic degradation of diuron,a toxic recalcitrant herbicide,on two forms of zinc oxide（ZnO）,i.e.,conventional particles with zinc-and oxygen-terminated polar surfaces as the dominating planes,and nanorods with mixed-terminated nonpolar surfaces.Experimental and theoretical results indicate that both the rate of reaction and the degradation pathway depend on the adsorption configuration of diuron onto the surface.Diuron molecules adsorb in different alignments on the two surfaces,contributing to the formation of different degradation intermediates.Both the aliphatic and aromatic sides of diuron adsorb on the polar surfaces simultaneously,leading to an attack by hydroxyl radicals from both ends.On the other hand,on the mixed-terminated surface,only the aliphatic part adsorbs and is degraded.The exposed surface is therefore the key factor controlling the degradation pathway.For diuron degradation on ZnO,a catalyst confined tomixed-terminated surfaces,i.e.,ZnO nanorods,is more desirable,as it avoids the formation of intermediates with potent phytotoxicity and cytogenotoxicity.

论文目录

• Introduction
• 1. Materials and methods
•   1.1. Synthesis of ZnO
•   1.2. Adsorption studies
•   1.3. Photocatalytic degradation
•   1.4. Toxicity tests
• 2. Results and discussion
•   2.1. Characteristics of ZnO catalysts
•   2.2. Adsorption of diuron and DCA on catalysts
•   2.3. Photocatalytic degradation
•   2.4. Diuron degradation intermediates
•   2.5. Toxicity of the degradation products
• 3. Conclusions

文章来源

类型: 期刊论文

作者: Sutaporn Meephon,Thanyada Rungrotmongkol,Somchintana Puttamat,Supareak Praserthdam,Varong Pavarajarn

来源: Journal of Environmental Sciences 2019年10期

年度: 2019

分类: 工程科技Ⅰ辑

专业: 环境科学与资源利用

单位: Center of Excellence in Particle Technology, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University,Biocatalyst and Environmental Biotechnology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University,Bioinformatics and Computational Biology Program, Graduated School, Chulalongkorn University,Department of Chemistry, Faculty of Science, Thammasat University,Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering,Chulalongkorn University

基金: funded by the Thailand Research Fund (No. DBG5580006)

分类号: X592

页码: 97-111

总页数: 15

文件大小: 2543K

下载量: 14