SiC/石墨烯复合纳米材料制备及其光电催化降解BFRs机理研究

The work aimed to eliminate brominated flame retardants (BFRs) from water. In view of the bromine atom that is easy to be reduced rather than oxidized due to its high electronegativity, this work will develop a SiC/grapheme (GNS) composite nanomaterial with enhanced quantum hall effect. The prepared SiC/GNS composite nanomaterial will be deposited on the titanium plant to make a photocathode with strong photoelectric activity. By analyzing the effect of quantum hall and measuring hall voltage of the electrode, the transmission of photogenerated carriers will be elucidated under the electrified light irradiation. The rate-limiting step during the reaction will be determined by exploring the influences of reaction conditions on the reductive debromination kinetics. The work will also provide insights into the debromination degradation mechanism of BFRs and the formation route of brominated intermediates by identifying the intermediate products and analyzing the dominating active free radicals during the photoelectrocatalytic reaction process. Furthermore, a systematic treatment strategy for removal of BFRs from water is expected to be obtained and optimized based on the above analyses. The results are expected to offer the theoretical basis and new technology for the elimination of BFRs from water by photoelectrocatalytic oxidation method.

本项目以水中难降解有毒有机物溴化阻燃剂（BFRs）为研究目标，针对BRFs苯环上溴原子电负性高的独特性质，拟研发具有量子霍尔强化效应的SiC/石墨烯（GNS）复合纳米材料，制备具有光电催化还原能力强的Ti基SiC/GNS阴极材料；阐明GNS量子霍尔效应在光电催化还原BRFs过程中的作用机制，揭示光照下电场诱导SiC颗粒表面光生载流子的电荷传递机理；建立不同反应条件下BFR电催化还原脱溴的反应动力学方程，明确影响光电催化降解BRFs过程的速率控制步骤；阐明光电催化反应条件下中间产物的变化规律和活性自由基的产生机理，揭示水中BFRs的光电催化脱溴降解机理；创建SiC/GNS复合纳米材料的制备技术及其光电催化降解水中BFRs的高效水处理工艺。研究成果可为净化水中难降解有机污染物BFRs提供理论指导和技术支撑。

溴化阻燃剂（BFRs）是我国产量和用量较大的有机阻燃剂，进入到环境水体中的BFRs难以自然降解，且含溴的降解中间产物生物毒性较大，威胁人体健康和生态安全，研究水体中BFRs类污染物的高效去除技术尤为必要。本项目以BFRs类污染物为研究对象，合成了不同金属修饰的SiC、石墨烯、Ti基复合纳米材料，建立了四溴双酚A、四溴联苯醚等典型BFRs污染物的降解动力学，考察了电极间距、电流密度、污染物初始浓度等影响因素对降解动力学的影响，通过反应过程中活性物种和降解中间产物检测，揭示了典型BFRs污染物脱溴反应途径和降解机理，初步建立了水中BFRs污染物光电催化降解新技术。本项目主要取得了以下三个方面的重要成果：（1）研发了具有普适性的单原子/纳米颗粒负载光电催化材料的制备方法，提出了通过单原子/纳米颗粒调控基底材料表面局域电荷排布和电子传输通道的方法，通过低温热处理可调控单原子的配位环境；（2）阐明了配位环境对材料催化性能的影响机理，建立了材料表面微观结构与催化性能的构-效关系，揭示了强金属-载体相互作用对界面电子传递和质子还原过程的影响机制；（3）构建光电催化降解体系，优化了运行参数，实现对典型BFRs降解率90~100%，脱溴率70~96%。降解中间产物检测结果表明，反应过程中生成了多种脱溴中间产物和完全脱溴产物，揭示了水中BFRs降解过程中加氢脱溴反应机理，初步建立了含BFRs废水高效低耗深度处理光电催化技术。该研究成果对于光电催化技术降解水中BFRs具有重要的理论意义和应用价值。