Synthesis a Clay Based Photocatalyst for the Removal of Eosin Yellow in Aqueous Solution

Abstract

Composite photocatalysts of clay and ZnO have been prepared using three different compositions and characterized by various techniques such as SEM, EDX, FTIR, and XRD. SEM micrographs in different magnifications revealed different morphology of composite particles rather than commercial ZnO and clay. The particle size of the prepared composite decreased with the increasing amount of clay and thus improves the catalyst surface area. EDX revealed that the composite contains clay and ZnO only. According to FTIR spectrum data, when the ratios of clay to ZnO are 12:88 and 25:75, all the clay particles are completely covered. The shift in the peak position of XRD patterns indicates the molecular level interaction between clay and ZnO. The composite photocatalyst with a composition of clay: ZnO = 25:75 has the highest capability to eliminate Eosin Yellow (EY) by both adsorption and photodegradation among the tested composite photocatalysts. At this composition, the degrading rate of 0.2 g of material in a 2×10-5 M aqueous solution was around 44.48% EY. However, after 60 minutes of photodegradation using UV light, the entire elimination of dye, including adsorption and photodegradation, is around 68.32%. As the concentration of EY increased, the degradation rate of EY reduced. It was discovered that the consequences of HCO3-, CO32-, Cl-, NO3-, and SO42- ions were deleterious to the photodegradation of EY. It was also discovered that the UV source was more effective than the visible source. An intense UV light causes EY to completely degrade.