Physicochemical characterization and evaluation of the photocatalytic activity of ZnO, NiO, TiO2 commercial oxides

Abstract

Traditional chemical, physical and biological processes for treating wastewater containing textile dyes have such disadvantages as high cost, high energy requirement and generation of secondary pollution during treatment process. The advanced oxidation processes (AOPs) technology has been attracting growing attention for the decomposition of organic dyes. Such processes are based on the light-enhanced generation of highly reactive hydroxyl radicals, which oxidize the organic matter in solution and convert it completely into water, CO2 and inorganic compounds. In this presentation, the photocatalytic degradation of dyes in aqueous solution using TiO2, ZnO, NiO as photocatalyst under solar and UV irradiation has been reviewed. It is observed that the degradation of dyes depends on several parameters such as pH, catalyst concentration, substrate concentration and the presence of oxidants. Reaction temperature and the intensity of light also affect the degradation of dyes. Particle size, BET surface area and different mineral forms of TiO2, ZnO, NiO also have influence on the degradation rate.