ZnO catalyzed degradation of methyl orange in aqueous medium

Synthesis and characterization of zinc oxide nano particles (ZnO NPs) and investigation of their catalytic activity for the degradation of methyl orange in aqueous medium has been reported in this work. ZnO NPs were prepared by reaction of zinc acetate dihydrate and sodium hydroxide in distilled water. The prepared ZnO NPs were characterized by XRD, FTIR, SEM TGA and surface area analysis. ZnO NPs were employed as catalyst for oxidative degradation of methyl orange in aqueous medium. The effects of various parameters like time, temperature, initial concentration of dye and catalyst dose on degradation experiments were investigated. Oxidative degradation reaction followed Eley-Rideal mechanism. According to Eley-Rideal mechanism the gaseous reactant, oxygen adsorbs at the surface of catalyst while methyl orange reacts in fluid phase. Adsorbed oxygen transform to reactive radicals through the formation of electron-hole pair between conduction and valence band of zinc oxide catalyst. These active radicals mineralized the dye into water and carbon dioxide.