Comparing photo-fenton degradation of malachite green using FeII and FeIII salts under UVA light irradiation

Abstract

Photo-Fenton degradation of pollutants involves the reaction of FeII salts with hydrogen peroxide under ultraviolet A irradiation, which significantly enhances the process. The reaction with FeIII salts is slower and therefore less studied. In this work, we compared the efficiencies of FeIII and FeII salts in the photo-Fenton degradation of malachite green (MG), a known carcinogen. We optimized the concentration of reagents and the pH to achieve the highest MG degradation with the lowest amounts of reagents. Complete MG degradation was achieved under 2 h for the FeIII system and 1 h for FeII, reaching a high degree of mineralization, even in the presence of chloride and sulfate anions. The results show that although slower, the reaction with FeIII salts allows significant photodegradation of MG under mild reaction conditions.