Photodegradation of methyl green by nickel-dimethylglyoxime/ZSM-5 zeolite as a heterogeneous catalyst

Abstract

Ni-DMG/ZSM-5 zeolite was prepared by ion exchange and complexation procedures. FT-IR, XRD, SEM, TG, and DTG methods were used for characterization of the raw and modified samples. The prepared composite was used as a catalyst in the photodegradation process of an aqueous solution methyl green (MG) dye under UV irradiation. The effect of key operating parameters such as catalyst dosage, temperature, the initial concentration of the dye, and pH of the samples was studied on the degradation extent of the dye. UV-Vis spectrophotometric measurements were performed for determination of the decolorization and mineralization extents. The optimal operation parameters were found as follows: pH = 9, temperature of 60°C, 0.6 g L-1 of the catalyst, and 40 ppm of the dye concentration. The Ni-DMG particles out of zeolite framework did not show significant degradation efficiency. The degradation process obeys the first-order kinetic. © 2013 Alireza Nezamzadeh-Ejhieh and Zahra Shams-Ghahfarokhi.