Decolorization of Methyl Orange Using Mill Scale by Photo-Fenton Reaction

Abstract

The textile dyeing industries generate large amount of effluents, sewage sludge and solid waste materials everyday which are being directly discharged into the surrounding channel, agricultural fields, irrigation channels, surface water and these finally enter into river. The presence of dyes in surface and subsurface water is making them not only aesthetically objectionable but also causes many water borne diseases. Various options have been being employed to treat such wastes. These include chemical treatment such as chlorination and ozonation, electrochemical treatment, physical treatment such as adsorption by activated carbon and membranes, biological treatment and advanced oxidation processes (AOPs). AOPs have attracted wide interests in wastewater treatment. AOPs are based on the generation of hydroxyl radicals in water, which are highly reactive and next on Selective oxidants being able to oxidize organic compounds particularly unsaturated organic compounds such as azo dyes. Among AOPs, two of the most important processes to generate hydroxyl radicals are using the photo-Fenton and photo-ferioxalate (Fe2+/H2O2/UV and Fe2+/OA/UV) systems. In the present study, the aqueous solution of Methyl Orange (MO), a model organic dye has been subjected to photocatalytic degradation by UV irradiation in presence of mill scale (iron oxide, solid waste generated in steel plants) containing different concentrations of H2O2 employing photo-Fenton process. The effect of various parameters such as initial mill scale amount, initial hydrogen peroxide (H2O2) concentration & initial dye concentration on decolorization process has been studied. The experiments were carried out by varying amount of mill scale (0.01-0.3g/100mL), initial concentration of dye (0.01-0.10mM/100mL) and hydrogen peroxide concentration (1-4mL/100mL). The optimum mill scale content was found to be 50mg/100mL. The degradation rate decreased with increasing dye concentration.