Ag^+、Ni^(2+)改性复合钛铌酸钾盐对二甲基硫和乙硫醇吸附与光催化氧化研究

Investigation of Adsorption and Photocatalytic Oxidation of Dimethyl Sulfide and Ethyl Mercaptan on Composite Potassium Titanoniobate Modified by Ag^+/Ni^(2+) Ion

由高温固相法制备复合钛铌酸钾盐,通过Ag+和Ni2+离子交换对其进行改性。采用红外光谱方法考察Ag+与Ni2+离子改性的复合钛铌酸盐对二甲基硫(DMS)和乙硫醇(EM)的吸附特征与光催化氧化作用。结果表明,复合钛铌酸盐对DMS与EM的吸附与光催化氧化行为取决于分子中S原子的环境与复合钛铌酸盐中阳离子的性质。DMS同Ag+与Ni2+离子改性的钛铌酸钾盐表面相互作用较弱,在自然光辐射下稳定,而EM同Ag+离子改性的钛铌酸盐具有明显的相互作用,即使在自然光辐射下也可被氧化。在紫外光辐射下,DMS和EM在两种离子改性的钛铌酸钾盐上均被催化氧化,DMS被氧化至亚砜、砜和硫酸酯,而EM被氧化至磺酸。

Potassium-modified titanoniobate photocatalysts were prepared by the solid-state method,through Ag+ and Ni2+ ion-exchange respectively. The adsorption features and photocatalytic oxidation activities for dimethyl sulfide (DMS) and ethyl mercaptan (EM) respectively on the as-prepared composite titanoniobates were evaluated through infrared spectroscopy techniques. The results show that the adsorption features and photocatalytic oxidation activities for DMS and EM on the as-prepared catalysts depend on surrounding of the S atom in the sulfides and nature of the cation in the titanoniobates. DMS is stable under visible light irradiation because of a weak interaction between it and the catalyst surface; however it is converted to DMSO, DMSO2, and sulfate under ultra-light irradiation. EM is converted to ethyl sulfonic acid over the catalyst modified by Ag+ ion-exchange even though under visible light irradiation because of a strong interaction between it and the catalyst surface. EM can be oxidized to sulfonic acid on the as-prepared catalysts by ultra light irradiation.