g-C3N4负载硫掺杂铋系复合物光催化-吸附控制烟气汞、砷的机理研究

燃煤电站是汞、砷污染物的主要人为排放源，零价汞、三价砷的有效控制是核心，不借助除尘器和脱硫塔从而不影响飞灰石膏等综合利用的烟气汞、砷脱除是一种更为理想的路径，具有重要的理论意义和应用价值。本项目提出石墨相氮化碳负载硫掺杂的铋系复合光催化剂对烟气零价汞、三价砷进行光催化氧化-吸附脱除的思想。研究石墨相氮化碳负载硫调控光催化剂表面活性点位、构建BiOI/BiOIO3异质结的机理，明确光催化剂的构效规律；研究复杂烟气组分下Hg0、As3+的光催化氧化-吸附反应过程，揭示烟气组分对零价汞、三价砷在复合光催化剂上光催化氧化-吸附反应行为的影响机制；结合微观分析及理论计算，探明汞、砷在催化剂表面形态转化及迁移过程，建立光催化氧化-吸附脱除汞、砷过程中烟气“扩散-表面吸附-光催化氧化-吸附-解吸附”反应动力学模型，揭示光催化氧化-吸附汞、砷及光催化剂再生的关键反应路径，丰富非均相光催化反应理论。

Coal-fired power stations are the main anthropogenic emission sources of trace mercury and arsenic pollutants. The effective controls of elemental mercury and trivalent arsenic is the core of emission reduction of the mercury and arsenic pollutants in the flue gas. A removal method of mercury and arsenic in flue gas is a promising emission control path, which is no need to rely on ESP and WFGD and so no effect on comprehensive utilization of fly ash and desulfurization gypsum, is with significant value for both theory and application. This project proposes g-C3N4 loaded with bismuth-based nanomaterials being doped with sulfur for photocatalytic oxidation-adsorption removal of elemental mercury and trivalent arsenic in flue gas. The mechanism of g-C3N4-supporting to enhance the surface activity of bismuth-based photocatalyst and construct BiOI/BiOIO3 heterojunction is to be studied, exploring structure-activity relationship of photocatalysts. Besides, the photocatalytic oxidation-adsorption processes of Hg0 and As3+ on the surface and inside of the composite catalyst under different flue gas components are to be studied, revealing the effects of other components of flue gas on the photocatalytic oxidation-adsorption behavior of elemental mercury and trivalent arsenic on composite catalysts. At the same time, combining micro-analysis and theoretical calculations, the change of valence state and migration process of mercury and arsenic on the catalyst surface are to be proved, the chemical reaction kinetic model of the flue gas diffusion, surface adsorption, photocatalytic oxidation and adsorption, and desorption during the process of photocatalytic removal on mercury and arsenic will be established by using the microanalysis and theoretical calculations. The key reaction pathways for photocatalytic oxidation and adsorption of mercury, arsenic and the photocatalyst regeneration are to be revealed, enriching the theory of heterogeneous photocatalytic reactions.