高效脱毒含铬废水的稳定MOFs光催化材料的设计及机理

Cr(VI) and organic pollutants coexisted wastewater (denoted as Cr(VI)-contenting wastewater) is difficult to be treated because of its complicated component, long process flow and difficult to separate the components on each. Moreover, the reaction mechanism of these systems is still unclear. In this proposal, a new way for preparing high-efficiency Cr(VI)-contenting wastewater detoxification photocatalysts is proposed by taking the advantage of unique properties of metal-organic frameworks (MOFs) materials. According to the detoxification requirements of Cr(VI)-contenting wastewater, a series of six-coordinate MOFs photocatalysts with strong surface Lewis acidity will be synthesized. By modifying the ligands with different substituent groups, different metal cluster secondary building units (SUBs) or using the specific synthesis modulators, the band structures (HOMO and LUMO) and the property of as-prepared MOFs will be tuned. Thus these materials are endowed with excellent adsorbability and their energy bands will be adjusted to correspond with the redox potential of reactive molecules. In addition, the adsorption, activation, reaction processes of the reactants and the possible intermediates during the reaction process will be investigated in detail. Based on the catalyst characterization and the catalytic performance evaluation, the mechanisms between the component, structure, and properties of the photocatalysts will be clarified, we will try to unravel the interaction relationship among the components, band structures and redox potential of reactive molecules. Furthermore, by combining with the calculation of quantum chemistry, the possible models of photocatalytic detoxification will be proposed and established. This study is expected to have significant academic value not only in guiding the design of novel and high efficient photocatalysts for the environmental remediation, but also providing a new insight in comprehensively understanding the nature of photocatalytic detoxification of Cr(VI)-contenting wastewater from molecule leve.

本项目针对含铬（Cr(VI)）有机废水（简称含Cr(VI)废水）处理工艺流程长，多组分不易分离，脱毒机制尚不明确等问题，拟利用金属有机骨架（MOFs）材料独特的物理化学性质来开展对含Cr(VI)废水一步光催化脱毒研究。根据含Cr(VI)废水的实际脱毒需求，通过有机配体修饰、金属中心调节、合成过程中加入配位调控剂等方法对MOFs的吸附位点与能带位置进行灵活调控，设计制备系列强Lewis酸性的六配位型MOFs光催化剂，使之既能针对性捕获污染物又能与其氧化还原电位相匹配，达到一步脱毒的目标。同时，利用MOFs精确的结构特征来考察反应物分子的吸附、活化及反应过程，探寻污染物在脱毒过程中的可能中间产物，并结合量子化学计算，阐明MOFs的构-效关系，建立光催化机理模型。该研究不仅对指导新型光催化脱毒材料的设计开发具有重大理论价值，而且对于从分子水平上深入理解废水光催化深度脱毒机制具有重要意义。

工业废水的深度处理是社会可持续发展面临的巨大挑战之一。本项目针对含铬（Cr(VI)）有机废水（简称含Cr(VI)废水）污染治理难度和巨大需求，提出利用金属有机骨架（MOFs）材料独特的物理化学性质来开展对含Cr(VI)废水一步光催化脱毒研究。根据含Cr(VI)废水的实际脱毒需求，通过有机配体修饰、金属中心调节、合成过程中加入配位调控剂等方法对MOFs的吸附位点与能带位置进行灵活调控，设计制备系列强Lewis酸性的六配位型MOFs光催化剂，使之既能针对性捕获污染物又能与其氧化还原电位相匹配，达到一步脱毒的目标。已成功制备出系列MIL-53(Fe)-CQDs-贵金属、AgBr-Ag@MIL-68(Fe)复合光催化材料，系统研究了上述MOFs复合材料对于Cr(VI)/染料双功能体系的吸附机制与光催化转化过程；阐明MOFs的构-效关系，建立光催化机理模型。此外，我们还开发出系列高效的新型光催化剂，并将其应用于光催化环境修复领域，如燃油脱氮、染料降解，药物及个人护理品（PPCPs）的脱毒反应等。该研究对丰富光催化科学基础，发展光催化技术在燃油脱氮中的实际应用具有十分重要的科学价值和实际意义。项目资助发表论文9篇，待发表2篇，其中SCI收录9篇。培养硕士生4名，职称晋升2人，项目组成员获评各类人才2人。项目直接经费23万元，支出17.5351万元，各项支出与预算相符。剩余经费5.4649万元，剩余经费计划用于本项目研究后续支出。