Polyaniline/ZnS nanocomposite as a novel photocatalyst for removal of Rhodamine 6G from aqueous media: Optimization of influential parameters by response surface methodology and kinetic modeling

Novel polyaniline/zinc sulfide (PANI/ZnS) nanocomposite in the role of photocatalyst was synthesized via a simplified method and was characterized by XRD, FT-IR, EDX and FE-SEM analysis. Modeling and optimization of photocatalytic removal of a hazardous xanthine dye, Rhodamine 6G (Rh-6G) from aqueous media by prepared nanocomposite was conducted using response surface methodology (RSM). Under optimum conditions (initial Rh-6G concentration = 4 mg L− 1, PANI/ZnS amount = 0.8 g L− 1, pH = 8 and irradiation time = 48 min) and exposure of UV-C light irradiation (20 W m− 2), photocatalytic process led to a remarkable removal of Rh-6G dye (80.62%). Reusability study of photocatalyst revealed a negligible decline of the process yield after five consecutive cycles. In continuation of our investigations, an empirical equation was obtained for estimation of apparent pseudo first- order rate constant (kap) as a function of influential parameters. In the final stage of the work, intermediate materials produced within photocatalytic degradation of Rh-6G dye were detected by GC-MS analysis.