Influence of operational parameters on photocatalytic decolorization of a cationic azo dye under visible-light in aqueous Ag3PO4.

• Ag 3 PO 4 photocatalyst was prepared by precipitation method. • Photocatalytic degradation of MB dye was studied under visible light irradiation. • The decolorization of MB was mainly affected by operational conditions. • The mechanism of higher initial pH playing a positive role is elaborated. The Ag 3 PO 4 nanoparticles were facilely prepared via the liquid precipitation method, and the physical property, optical properties, crystalline and morphologic properties were explored using various techniques. The XRD and SEM results show Ag 3 PO 4 nanoparticles possessed the cubic phase structure and spheroid-like morphology with a particle size of about 300–500 nm. Spectra analysis results indicated that nanoparticles prepared had the same functional groups as Ag 3 PO 4 and can absorb visible light with wavelengths less than 530 nm. The photocatalytic degradation of a cationic azo dye methylthionine chloride (MB) using Ag 3 PO 4 as a photocatalyst in aqueous solution has been investigated under visible-light irradiation. The effects of different parameters on the photodegradation of MB were analyzed. During visible light photocatalytic degradation of MB in the water at different pH values by the Ag 3 PO 4 catalyst, the process was found along with a regular dependency between the degradation rate and adsorption capacity. Both the adsorption efficiency and degradation efficiency of MB on Ag 3 PO 4 increased with increasing initial solution pH value. Ag 3 PO 4 nanoparticles show excellent photocatalytic activity against cationic azo dye under visible-light irradiation and are expected to be effective as a promising visible-light photocatalyst for textile-dyeing wastewater remediation. [ABSTRACT FROM AUTHOR]