Ag-AgIO3改性BiOI光催化剂湿法脱除气态单质汞

采用沉积沉淀-光还原法制备了不同AgIO₃含量的BiOI光催化剂，利用X射线衍射、N₂吸附-脱附、扫描电子显微镜、X射线光电子能谱、紫外-可见漫反射光谱和电子自旋共振对其物理化学结构进行表征，在光催化反应器上研究了AgIO₃负载量、光照、溶液温度、pH值、SO₂和NO对气态单质汞（Hg⁰）去除性能的影响.结果表明，与BiOI相比，Ag-AgIO₃改性后光催化剂的脱汞性能大幅提高.当AgIO₃负载量为4wt.%时，光催化剂的脱汞效率高达98%.与NO相比，SO₂对脱汞性能的抑制作用更大.由于Ag和AgIO₃在BiOI表面的高度分散性，Ag-AgIO₃（4%） BiOI的可见光吸收性能明显提高.荧光灯辐照与Ag-AgIO₃/BiOI光催化剂协同会产生大量的活性物种.在Ag-AgIO₃/BiOI光催化剂的高效脱汞体系中，超氧阴离子自由基（·O₂^-）为最主要的活性物质，而空穴（h⁺）和羟基自由基（·OH）次之.

Wet process of gaseous Hg0 removal by Ag-AgIO3 modified BiOI photocatalyst

A series of Ag-AgIO₃/BiOI photocatalysts were successfully synthesized by a coprecipitation-photoreduction method and characterized by X-ray diffraction (XRD), N₂ adsorption-desorption, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS) and electron spin resonance (ESR). The effects of AgIO₃ content, fluorescent lamp (FSL) irradiation, solution temperature, pH value, SO₂ and NO on Hg⁰ removal were investigated in a photocatalytic reactor. In comparison to BiOI, Ag-AgIO₃ photocatalyst exhibited an enhanced fluorescent-light-driven photocatalytic activity for Hg⁰ removal. When the loading of AgIO₃ was 4wt.%, the removal efficiency of the Ag-AgIO₃/BiOI photocatalyst was as high as 98%. Compared with NO, the inhibitory effect of SO₂ on Hg⁰ removal efficiency became predominant. Due to the high dispersibility of Ag and AgIO₃ on the surface of BiOI, the visible light absorption performance of Ag-AgIO₃(4%)BiOI was significantly improved. The combination of fluorescent lamp irradiation and Ag-AgIO₃/BiOI photocatalyst could produce a large number of active species. The mechanism showed that in the efficient mercury removal system of the Ag-AgIO₃/BiOI photocatalyst, the superoxide radical (·O₂^-) was the most important active material, and the holes (h⁺) and hydroxyl radical (·OH) were the secondary factors.