Copper modified iron oxide as heterogeneous photo-Fenton reagent for the degradation of coomasie brilliant blue R-250

The heterogeneous photo-Fenton degradation of coomasie brilliant blue R-250 under visible light has been investigated using copper modified iron oxide, which has been prepared by coprecipitation method and characterized by IR spectroscopy, scanning electron microscopy and X-ray diffraction. The rate of photocatalytic degradation of dye follows pseudo-first order kinetics. The effects of various parameters like pH, concentration of dye, amount of photocatalyst, amount of H2O2 and light intensity on the rate of the photo-Fenton degradation has also been studied. Chemical oxygen demand of the reaction mixture before and after exposure has been determined. A tentative mechanism for the photocatalytic degradation has been proposed, wherein involvement of (OH)-O-center dot radicals has been confirmed by the drastic reduction in the reaction rate in the presence of (OH)-O-center dot radical scavengers such as isopropanol and butylated hydroxy toluene. The retardation with butylated hydroxy toluene is much higher than with isopropanol. Under similar conditions, efficiencies of Fe2O3 and copper modified Fe2O3 have been compared for the photocatalytic degradation of coomasie brilliant blue R-250.