基于有机氯农药废水降解的磁性生物炭基Ag/AgX/BiOX异质结复合光催化剂的制备及增强活性机理研究

Organochlorine pesticides (OCPs) are a kind of typical and persistent organic chlorine pollutants, which have the characteristics of the high toxicity, high biological concentration and the difficult biodegradation. It is very difficult to treat waste water generated in the process of the production of organochlorine pesticides. However, the environmental quality condition of our country decides that this kind of waste water has to be disposed. Therefore, the economic and efficient photocatalytic degradation to organic chlorides has extremely important practical significance to the environmental protection. The aim of this project is to design the novel magnetic biochar-based Ag/AgX/BiOX heterojunction composite photocatalysts with the surface modified magnetic biochar as a medium and with the Ag/AgX/BiOX heterojunction composite as a photocatalyst. We will build a convenient preparation method of magnetic cellular tube biochar materials, obtain the biochar materials with the regular morphology and the excellent performance and study the forming mechanism of the cellular tube biochar. We will also acquire the synthesis process of magnetic cellular tube biochar-based Ag/AgX/BiOX heterojunction composite photocatalysts. In addition, we will discuss the electronic transfer behavior and the coupling mechanism between the Ag/AgX/BiOX heterojunctions and the biochar materials. The catalytic mechanism that the composite photocatalysts degrade the organic chlorides will be revealed. The ultimate goal of this project is to provide the experimental basis and the theoretical guidance for the application of the metal/semiconductor/carbon based materials in the degradation of the organic chlorides.

有机氯农药（OCPs）是一类典型的持久性有机氯污染物，具有高毒性、高生物富集性和难以生物降解等特点。有机氯农药生产过程中产生的废水处理难度较大，而我国的环境质量状况又决定该类废水必须进行处理。因此，对其进行经济、高效的光催化降解对保护环境有着极其重要的现实意义。本课题旨在以表面修饰改性磁性生物炭为载体，以Ag/AgX/BiOX异质结复合材料为光催化剂，设计新型磁性生物炭基Ag/AgX/BiOX异质结复合光催化剂；构建便捷的磁性蜂窝管生物炭材料制备方法，得到形貌规整、性能优良的磁性生物炭材料并研究蜂窝管生物炭的成型机制；获得磁性蜂窝管生物炭基Ag/AgX/BiOX异质结复合光催化剂的合成工艺；探讨Ag/AgX/BiOX异质结与生物炭材料的电子迁移行为及其耦合机理；揭示复合光催化剂光催化降解有机氯化物的催化机理。为将金属/半导体/碳基材料复合光催化剂应用于有机氯化物降解提供实验依据和理论指导。

摘要：水环境中的有机污染物种类繁多，大多数具有高毒性、高生物聚集性、持久性和难降解等特点，对生态环境的可持续发展构成了严重威胁。因此，对其进行绿色、经济、高效的光催化降解对保护环境有着极其重要的现实意义。本课题以生物炭材料、磁性材料和半导体材料为主体，设计并构建了多种新型的磁性生物炭基贵金属/半导体复合材料，实现了对农药、有机染料和酚类化合物等多种有机污染物的高效催化降解。通过对生物炭原材料的选择和合成调控，获得了不同尺寸和形状的生物炭材料，同时成功制备得到了生物炭/半导体复合材料、贵金属/半导体/生物炭复合材料以及磁性核/生物炭/半导体复合材料。此外，本课题还通过调控超顺磁性Fe3O4的合成工艺，结合种子沉积法制备了Fe3O4/半导体/贵金属Ag纳米复合材料。我们以农药、有机染料和酚类化合物等多种有机污染物作为目标降解物，通过研究贵金属、生物炭、磁性材料与半导体材料间的电子迁移行为及耦合机理，揭示了磁性生物炭基多功能纳米复合催化剂降解有机污染的催化机理。本课题不仅实现了将物理、化学、材料等多学科的交叉，还为将半导体材料、磁性材料和碳基材料复合催化剂应用于有机污染物降解提供了实验和理论指导。