Semiconductor Assisted Photodegradation of Textile Dye

Abstract

The degradation of commonly used textile dye reactive red 2 in an aqueous solution by means of photocatalysis using ZnO in the form of slurry is studied. The influence of initial concentration of the dye, pH of the reaction mixture. Catalyst loading, the presence of oxygen, hydrogen peroxide, and potassium persulphate on the degradation rate is observed. When concentration of the dye increases from 60 to 140 ppm, the rate constants vary between 0.055 and 0.019 min^-1. The disappearance of the dye follows approximately pseudo-first order kinetics. For an irradiation time of 60 min, 86 per cent COD reduction is noted, whereas 100 per cent degradation observed at 300min of irradiation time. The oxidising agents (oxygen, hydrogen peroxide and potassium persulphate) enhance the degradation rate of the dye. Carbonate ions present in dye solution inhibit the degradation rate of the dye. This method suggests the possible use of ZnO photocatalysed degradation of textile dye present in wastewater.