Photo-decolourization kinetics of acid red 87 dye in Zno suspension under different types of UV-A light

Abstract

Present study confirmed that the essential requirements for photo-decoulorizationof acid red 87 (Eosin yellow) dye solution are dependent on the presence of the UV light and a photocatalyst ZnO. A kinetics and thermodynamics studies of decolourization phenomenon involved in the photocatalytic decolorization of acid red 87 dye solutions was performed in suspension solution of the commercial ZnO, under the artificial light (high pressure mercury lamp) types 125 and 250 watt as UV A source.The photoreaction of this dye was obeyed to pseudo-first order kinetics and the calculated activation energies for this dye with using 125 and 250 watt were found to be 26.012 KJ and 29.397 kJ mol-1, respectively, which indicated the fast photo-reaction and decreased energy barrier. On the other hand, the reaction is endothermic and non-spontaneously. The optimum conditions for the photocatalytic decolorization of Acid Red 87 were performed. The best dose of ZnO to remove 50 ppm from this dye is 300 mg/100 mL and maximum value for the initial pH of an aqueous solution of dye is 6.