Degradation of organic dye using a new homogeneous Fenton-like system based on hydrogen peroxide and a recyclable Dawson-type heteropolyanion

Abstract

The main objective of this work was to study the degradation of Acid Orange 7 (AO7) dye in aqueous solution by hydrogen peroxide using HFe2.5P2W18O62 23.H2O as a catalyst. HFe2.5P2W18O62 23.H2O is a recyclable DAWSON-type heteropolyanion. Effects of various experimental parameters of the oxidation reaction of the dye were investigated. The studied parameters were the initial pH, the initial H2O2 concentration, the catalyst mass, and the dye concentration. The optimum conditions had been determined, and it was found that efficiency of degradation obtained was about 100%. The optimal parameters were: initial pH 4; [H2O2]0 = 2 mM; catalyst mass 0.01 g; concentration of dye 30 mg/L. Infrared spectroscopy analysis of the HFe2.5P2W18O62 23.H2O catalyst indicates that the catalyst showed good stability for degradation of AO7 even after second cycle.