Optimization and Degradation Mechanism of Photocatalytic Removal of Bisphenol A Using Zn_0.9 Fe_0.1 S Synthesized by...

The sulfide photocatalyst of Zn_0.9 Fe_0.1 S was successfully synthesized by a facile microwave-assisted method, and Zn_0.9 Fe_0.1 S photocatalysts were characterized using SEM, EDX, XRD and BET. The specific surface area of synthesized Zn_0.9 Fe_0.1 S is 78.1 m² g^-1 , and total pore volume is 0.4 cm³ g^-1 . With bisphenol A (BPA) as a target pollutant, photocatalytic system of UV + Zn_0.9 Fe_0.1 S + H₂ O₂ was set up. Some influencing parameters, including H₂ O₂ dosage, initial pH value, initial concentration of BPA and Zn_0.9 Fe_0.1 S dosage, were investigated, and the stability of the Zn_0.9 Fe_0.1 S was also studied during the photocatalysis. The optimum values of operating parameters were found at an initial pH value of 5.0, a H₂ O₂ dosage of 0.15 mmol L^-1 and a Zn_0.9 Fe_0.1 S dosage of 0.08 g when the initial concentration of BPA was 10 mg L^-1 . Under the optimal conditions, the highest removal rate of BPA achieved 95%. After seven consecutive reaction cycles, the degradation efficiency of BPA could still reach 85% and there was only a little dissolution of Zn²⁺ and Fe²⁺ . Compared with the traditional photo-Fenton system, the UV + Zn_0.9 Fe_0.1 S + H₂ O₂ system can not only improve the degradation efficiency of BPA, but also reduce the dosage of H₂ O₂ and thus reduce the processing cost.