Synergistic Catalytic Action of Fe0, Fe2+ and Fe3+ in Fenton Reaction for Methyl Orange Decolorization

Fenton and Fenton-like reactions are well known to be a very effective method in the removal of many hazardous organic pollutants. The reactions are activated by the mixtures of hydrogen peroxide (H2O2) and catalysts (metal iron; Fe-0, Fe2+ and Fe3+) to generate hydroxyl free radical (OH center dot), which is a strong oxidizing agent in the acidic pH range of 2.5 - 3.0. This study aimed to observe a synergistic catalytic action on Fenton and Fenton-like reactions with a combination of catalysts for Methyl Orange decolorization using experimental methodology via multilevel factorial design. It was revealed that efficiency of decolorization from a synergistic catalytic action was higher than the reactions with either Fe-0, Fe2+ or Fe3+ alone on Methyl Orange decolorization. In the mixtures with Fe-0, Fe2+, and H2O2 at pH 3 within 10 min, efficiencies of Methyl Orange removal with initial concentration of 75 mg/l were 84 and 99 % when the reaction systems were added with 10 mg/l of each synergistic catalyst and 25 and 50 mg/l of H2O2 with the rate of decolorization of 6.69 and 7.47 mg/l/min, respectively.