PHOTOCATALYTIC DEGRADATION OF RB21 DYE BY TIO2 AND ZNO UNDER NATURAL SUNLIGHT, MICROWAVE IRRADIATION AND UV-REACTOR

The present work aims to degrade the RB21 dye from synthetic wastewater using semiconductors TiO2 and ZnO. The activity of photocatalytic degradation process of dye was carried out using different light sources of 900 W/m 2 intensity in natural sunlight from 02:00 to 04:00 pm with 48°C temperature in Ahmedabad city in the month of May, 600 Watt microwave oven and high pressure UV-light photocatalytic reactor of wavelength 200-450 nm. All the experiments were performed with dye concentration 50 mg/L, catalyst dosage 0.8 g, pH 7, room temperature, irradiation time 240 min followed by 30 min in dark. All the samples were collected at different time intervals of 30, 60, 90, 120, 150, 180, 210, 240 min for the analysis of COD degradation and color removal. The best performances was achieved using high pressure UVphotocatalytic reactor using TiO2. The successful result obtained using TiO2is 80% COD degradation and 99% color removal followed by 75% COD and 99% color removal with ZnO. Chemical kinetics was found to follow first order mechanism. The formation of intermediate compounds and identification of the final products were carried out using LCMS/MS analysis and FT-IR techniques.