Investigation of affecting operational parameters in photocatalytic degradation of reactive red 198 with TiO2: optimization through response surface methodology

Dye-containing wastewater generated from textile industries is a major source of environmental pollution. Azo dyes, which are the largest group of coloring agents, are widely used in industries.This research investigated the photocatalytic decolorization and degradation of an azo dye Reactive Red 198 (RR198) in aqueous solution with TiO2-P25 (Degussa) as photocatalyst in slurry form using UV light. There is a significant difference in adsorption of dye on TiO2 surface with the change in the solution pH. The effect of various parameters such as catalyst loading, pH and initial concentration of the dye on decolorization and degradation have been determined. The optimum conditions of the reactor were acquired at dye concentration = 62 ppm, pH = 3.7, catalyst concentration = 2.25 g.L-1, in which dye removal efficiency was 98%. Catalyst loading (relevant coefficient = 19.25) and pH (relevant coefficient = −2.62) were resulted respectively as the most and less effective parameters on dye removal