纳米结构Ta3N5基大面积无纺布光催化剂的设计、构筑及其在净化流动污水中的应用

Photocatalytic technology has great potential in the application of the decontamination of the polluted water, and a prerequisite for photocatalytic application is to obtain excellent photocatalysts. Traditional nanosized photocatalysts usually have high photocatalytic activity but can not be efficiently recycled; and film-shaped photocatalysts on the substrate can be easily recycled, but they have low surface area and/or high production cost. To solve these problems, this project aims to develop efficient and easily recyclable macroscale photocatalysts with nanostructure: the case of nanostructured Ta3N5-based macroscale nonwoven-cloth photocatalyst for the decontamination of flowing sewage. This project consists of three steps. The first step is to design and prepare nanostructured Ta3N5-based macroscale nonwoven-cloth by an electrospinning based method. The second step is to measure the photocatalytic activity of the Ta3N5-based nonwoven-cloth, and to investigate the effects of compositions, morphologies, fabric structure and etc on the photocatalytic performance, and then to select efficient, stable and easily recyclable nonwoven-cloth photocatalysts. The last step is to design and construct novel multiple-stage photocatalytic devices with Ta3N5-based nonwoven-cloth as the photocatalyst-based filter-membrane for the purification of flowing sewage, and to investigate the relationships among stage number of photocatalytic devices, decontamination efficiency, and treatment cost. This project will not only lay a foundation for the future development of efficient, stable and easily recyclable nonwoven-cloth photocatalysts, but also make important contributions to the practical application of photocatalytic technology, for example, degrading pollutants in lake and/or river.

光催化技术在处理污水方面已经展现了巨大潜力，但是其应用前提是开发优异的光催化剂。纳米光催化剂有较好性能，但是难以回收；衬底固定的光催化剂容易被回收，但是比表面积小或成本高。为了解决这些难题，本项目旨在开发高效稳定且易回收的宏观尺度纳米结构光催化剂，以Ta3N5为例制备纳米结构Ta3N5基大面积无纺布光催化剂，并将其用于净化流动污水。主要研究内容包括：(1)设计纳米结构Ta3N5基无纺布，再发展以静电纺丝为基础的方法来制备无纺布，探索其生长机理；(2)测试无纺布的光催化性能，探索其组分、形貌和织物结构等对其光催化活性的影响规律，筛选出高效稳定且易回收的无纺布光催化剂；(3) 以Ta3N5基无纺布为光催化剂滤膜，设计并构造可用于净化流动污水的多级光催化装置，探索装置级数、降解效率、处理成本等之间关系。该项目将为发展高效稳定和易回收的无纺布光催化剂奠定基础，也为光催化技术走向实用做出重要贡献。

随着工农业的发展，废水排放量越来越多，中国2015年废水排放量高达73.53 km3；废水中主要包含大量的有机和重金属污染物，这些污染物严重威胁人类健康。光催化技术在处理污水方面已经展现了巨大潜力，但是其应用前提开发高效稳定且易回收的光催化剂。本项目旨在开发高效稳定且易回收的宏观尺度纳米结构光催化剂，以Ta3N5 为例制备纳米结构Ta3N5 基大面积无纺布光催化剂；并将其用于净化流动污水。实际上发展了三类制备技术来构建纳米结构大面积光催化剂。第一类是以静电纺丝为基础的路线构筑半导体异质结纤维基无纺布光催化剂，获得了Ta3N5/Bi2MoO6、Fe2O3/AgBr和NiTiO3/Bi2MoO6等3种无纺布，这些纤维基无纺布都具有优异的光吸收能力和光催化活性；例如Ta3N5/Bi2MoO6纤维基无纺布能在光照60分钟后降解99.5%罗丹明B。第二类是以碳纤维(CFs)束为衬底构筑柔性可编织光催化剂，获得了CFs/TiO2、CFs/TiO2/Bi2WO6、CFs/TiO2/MoS2等三种柔性可编织纤维；将它们编织成大面积布后，都具有良好的光催化和光电催化性能。第三类是以碳纤维布为衬底构筑大面积滤膜状光催化剂，获得了CF/C3N4、CF/TiO2/C3N4、CF/MoS2/Bi2S3和CF/C3N4/Ag-Ag2O等4种大面积滤膜，它们都可作为光催化滤膜来降解流动污水。例如，以CF/C3N4布(4 × 4 cm2)为滤膜状光催化剂来构筑新型光催化装置用于降解流动污水，以RhB水溶液为模拟流动废水(流速：1.5 L h-1)，经过7级反应，去除效率从第1级的18%上升到第7级的92%。另外，还开发了一系列新型粉末状半导体光催化剂，发现它们都具有较好的可见光光催化活性。同时，也探索了其它新型光功能材料及其应用。发表标注受本项目资助的论文有28篇，其中在Appl. Catal. B: Environ.、Nano Energy、Water Research、J. Hazard. Mater.、Environ. Sci.: Nano等重要期刊上共发表SCI论文26篇。申请的专利有4项，另外已经授权专利有3项。项目主持人参与并获得教育部自然科学二等奖(证书编号2015-116)。