A highly photoactive Ce-doped nano ZnSphoto catalyst: Synthesis and characterization for enhanced photocatalytic degradation of Congo red form aqueous sample solution

Environmental problems associated with hazardous wastes and toxic water pollutants have been attracted much attention. Among them, organic dyes are one of the major groups of pollutants in wastewaters. Among various physical, chemical and biological techniques for treatment of wastewaters, heterogeneous photocatalysis has been considered as a cost-effective alternative for water remediation. The photocatalytic treatment of wastes containing dyes has also been wildly reported in the literature. In most cases, TiO2 was used as a famous photocatalyst, whereas, the other semiconductors such as metal sulfides were lesser used especially in the dimensions of nano-scale. In this study, a novel and high efficient nanophotocatalyst of zinc sulfide as undoped and doped with cerium were used as photocatalyst in the photodegradation of congo red. The characterization of nanoparticles was studied using X-ray powder diffraction (XRD) patterns and diffuse reflection spectroscopy (DRS) analysis. Experimental condition including pH, dye concentration, photocatalyst concentration and temperature were optimized. The most degradation efficiency was obtained in acidic pH around 4 with study of photodegradation in pH amplitude of 2–12. The degradation efficiency was decreased in dye concentrations above of 20 mg/L. Because of synergetic effect of Ce on Ce-doped ZnS catalyst the activity would be increased than undoped ZnS. Furthermore, coupling of electrical current with photocatalytic process has proven to be effective in the degradation of congo red aqueous solution clearly.