Screening of various hybrid composite materials for removal of extremely toxic acid yellow dye from wastewater

About 40,000 synthetic pigments and dyes are consumed in different industries throughout the world that severely contaminate water sources. The present study has been undertaken to remove extremely toxic and hazardous acid yellow dye from water. In total seven hybrid nanocomposites were pre -pared by mixing various materials with calcinized white stone powder (CWSP) and screened out for their dye removal efficiencies. The functional groups involved in the dye adsorption using 2% Cu/TiO2 composite with calcinized white stone powder were Si-O, -CO and -OH. Scanning electron microscopy micrographs of 2% Cu/TiO2 composite with calcinized white stone powder show that it has nano-granular structure as compared to other materials. The presence of distinctive and sharp peaks in X-ray diffraction indicated the crystalline nature of white stone powder, CWSP and 2% Cu/TiO2-CWSP composite. The zeta potential measurements (-22.4 mV) of calcinized white stone powder indicate that these have anionic nature. The overall acid dye removal efficacy of various hybrid nanocomposites was in the following order: Cu/TiO2-CWSP composite > Li/TiO2-CWSP composite > CaO-Fe3O4-CWSP composite > CaO-Fe2O3-CWSP composite > FeSnO4-CWSP composite, FeCdO-CWSP composite > Na2SiO3-CWSP composite. It is important to note that adsorbents have shown good adsorption at 30degree celsius and 40degree celsius. The optimized conditions for maximum removal of dye were pH 7, dose 0.05 g/L, initial concentration 40 mg/L and temperature 40degree celsius. Almost 99.19% of acid yellow dye was removed by Cu/TiO2-CWSP composite under optimized conditions.