A Comparative Study between Photocatalytic activity of ZnO/bentonite Composites Prepared by Precipitation, Liquid-state Ion Exchange and Solid-state Ion Exchange Methods

The purpose of this research is to produce ZnO/bentonite nanocomposites with precipitation, liquid-state ion exchange (LSIE) and solid-state Ion exchange (SSIE) methods and compare their photocatalytic activity. The physicochemical properties of the prepared photocatalysts were determined by scanning electron microscope (SEM), energy dispersive X-ray (EDX) and diffusive reflective spectroscopy (DRS) analysis. The Photocatalytic activity was evaluated by degradation of methyl orange (MO) with prepared photocatalysts. SEM images showed that the ZnO particles were successfully distributed on the bentonite in the samples prepared by precipitation method. Nevertheless, after ion exchange-based methods, no particles were formed on the bentonite surface. The EDX analysis showed that the Zn contents in the ZnO/bentonite were 0.39, 0.44 and 0.66% prepared with LSIE, SSIE and precipitation methods, respectively. Based on changes in the UV–vis spectrum of Parent zinc chloride and bentonite, the DRS analysis confirmed the formation of ZnO/bentonite composites. The photo-degradations of MO were 85, 87 and 84% for the composites prepared by LSIE, SSIE and precipitation methods, respectively. Finally, the photocatalytic composites prepared by the solid-state method were very bright due to their simple production, low price and short time due through direct heating of the reaction.