Preparation Of Silver Phosphate Composite Photocatalyst And Study On The Properties Of Degradation Organic Compounds Under Visible Light

Semiconductor photocatalytic degradation of organic matter is one of the important technologies to solve the increasingly serious environmental pollution problems. Among semiconductor photocatalysts, the silver phosphate catalyst is the newly discovered photocatalytic materials in recent years, which has a very strong photocatalytic ability under visible light irradiation. It can not only absorb the wavelength less than 520 nm in the light of the sun, but also the quantum yield under visible light is higher than 90%. Many effective methods have been proposed to improve the photocatalytic activity and stability of silver phosphate. Among them, the dispersion of silver phosphate to support to form nano silver phosphate composite photocatalyst, which combines the characteristics of nano particles and carrier, is an effective hot method to enhance the photocatalytic activity and stability of silver phosphate. This paper selects two different carrier (sepiolite and carbon microspheres) Silver phosphate wers successfully loaded onto the carriers in two different methods, which form sepiolite/Ag3PO4 and CMSs@Ag3PO4 composite photocatalyst. Specific methods and main conclusions are as follows:1、The characterization of the two kinds of composite photocatalyst were accomplished by means of XRD, SEM, HRTEM, XPS, BET, Uv-vis, PL and other characterization means. The results show that the addition of the carrier can significantly reduce the agglomeration of the phosphate in the composite photocatalyst and enhance its light absorption intensity in the visible light range.2、The photocatalytic degradation of 2,4-DCP with sepiolite/Ag3PO4 composite photocatalysts were screened through the P-B design. The results show that:pH, catalyst investment and the amount of hydrogen peroxide concentration are the main factors that influence the removal rate of 2,4-DCP. The main influence factors of the reaction process:pH, initial H2O2 concentration and catalyst dosage were optimized by BBD design. The results show that the optimal experimental conditions for the pH is 4.01, initial concentration of H2O2 for 35.26mM, catalyst dosage of 0.36 g/L, and under these conditions, the prediction of 2,4-DCP removal rate could reach to 84.65%, TOC removal rate reaches 64.48%, the experimental values were 84.50% and 64.39%.3、The two kinds of compound photocatalyst were reused in the experiment. The results showed that:sepiolite/Ag3PO4 still exhibited good catalytic activity and stability after repeated three times; CMSs@Ag3PO4 still show good catalytic activity and stability after repeated four times.4、The species of reactive oxygen species in the reaction process were investigated by a free radical trapping experiment. The results showed that hydroxyl free radical, superoxide radical, photogenerated holes are involved in the process of the degradation of organic matter. Photoinduced hole play a major role in the sepiolite/Ag3PO4 photocatalytic reaction and superoxide radicals plays a major role in the CMSs@Ag3PO4 photocatalytic reaction.