Enhanced photocatalytic degradation kinetics of azo-dyes by novel Ni2+ and Ag2+ doped ZnO nanocatalysts

Abstract

Zinc oxide (ZnO) nanocatalyst was doped with nickel (Ni2+) and silver (Ag2+) by co-precipitation method for effective degradation of acid blue 113 dye (AB113) from textile industries wastewater. The synthesized co-doped nanocatalyst was characterised using a scanning electron microscope, and its size was around 50-200 nm. The elemental constituents of Ag2+ and Ni2+ in the co-doped zinc oxide nanocatalyst have analysed the results of energy dispersive analysis. The effects of the process parameters pH, initial dye concentration and catalyst loading were optimized to get the maximum dye removal from the wastewater. The acid blue 113 dye gets degraded entirely once it was subjected to irradiation of 120 min. The co-doped and un-doped zinc oxide nanocatalyst were used to degrade dye molecules. The co-doped ZnO nanocatalyst was twice effective as the un-doped ZnO nanocatalyst in the entire dye degrading phenomena upon exposure to the sunlight. The kinetic models have been applied to predict kinetic behaviour, and its mechanism. The present study promotes the importance of co-doped ZnO nanocatalysts in the treatment of azo dyes discharged from the textile industry.