Effect of Operational Parameters on Photodegradation of Methylene Blue on ZnS Nanoparticles Prepared in Presence of an Ionic Liquid as a Highly Efficient Photocatalyst

M. Barjasteh-Moghaddam and A. Habibi-Yangjeh*

Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran

In the present study, photocatalytic degradation of methylene blue (MB) on ZnS nanoparticles, prepared in aqueous solution of a room-temperature ionic liquid (RTIL), was studied and the results were compared with commercial ZnS. Influence of various operational parameters such as calcination temperature, catalyst weight, pH of solution, and initial concentration of MB on the photodegradation reaction was investigated to achieve maximum degradation efficiency. The optimum value of pH and catalyst dose was found to be 9.5 and 0.6 g l^-1. It was demonstrated that the photodegradation of MB follows a pseudo first-order kinetic. At optimized conditions, the rate constant of the reaction on ZnS nanoparticles prepared in aqueous solution of the RTIL is about five and four times greater than the prepared sample in water and commercial ZnS, respectively.

Keywords: ZnS, Photocatalysis, Room-temperature ionic liquid, Methylene blue, Nanoparticle