Synthesis scaly Ag-TiO2 loaded fly ash magnetic bead particles for treatment of xanthate wastewater

It is a challenging problem which Titanium dioxide (TiO2) has low utilization of visible light and difficult recovery. In this work, the Ag-TiO2-FAMB photocatalyst was prepared by the sol-gel method, with Ag as the dopant and Fly Ash Magnetic Bead (FAMB) as the carrier to improve its photocatalytic performance and recovery rate. The samples prepared were characterized by XRD, SEM, EDS, VSM, UV-vis diffuse reflection. The effects of the amount of photocatalyst, initial pH value and concentration of xanthate, and the intensity of light on the degradation of xanthate were investigated. Free radical quenching test, full-spectrum ultraviolet scanning, and ion test are used to explore the potential mechanism of xanthate degradation. The test results show that the synthesized Ag-TiO2 is scaly and uniformly supported on the surface of FAMB and its response of the photocatalyst to visible light shifts to 475 nm. When the photocatalyst concentration is 3.0 mg/L, the initial pH value is 5.0, the initial concentration of xanthate is 10.0 mg/L and the light intensity is 250 W, the degradation rate of xanthate reaches 98.5% after 30 h of light. The photocatalyst recovered by the external magnetic field was reused 5 times, and the degradation rate of xanthate remained above 83.8%. Superoxide radical (& sdot;O2- ) is the main active species for photocatalytic degradation of xanthate, and xanthate peroxide (ROCSSO-) is an intermediate product, which is finally degraded into CO2, SO42-, H2O.

Automated summary

The Ag-TiO2-FAMB photocatalyst was successfully prepared by the sol-gel method to improve its photocatalytic performance and recovery rate, with superoxide radicals identified as the main active species for the degradation of xanthate into CO2, SO42-, H2O.