Removal of Eosin Yellow dye from industrial wastewater using UV/H2O2 and photoelectro-Fenton techniques

Abstract

This work investigates the feasibility of applying photochemical advanced oxidation as a viable technique to overcome the ecological issue of stubborn organic contaminants. UV/H2O2 and photoelectro-Fenton processes were used for degradation of Eosin Yellow in its solutions. The operational variables examined for UV/H2O2 are solution pH, initial concentration of dye, H2O2 dosage and superficial velocity of oxygen sparging. Meanwhile, oxygen flow rate, applied current density, initial concentration of dye and the cathode thickness were tested for photoelectro-Fenton method. Decolorization was achieved by 99.9 % removal using UV/H2O2 method within 60 min at 200 ppm Eosin Yellow concentration and 50 mM of H2O2 and superficial oxygen velocity of 5 cm/s. The optimum conditions of photoelectro-Fenton method are 200 ppm initial concentration of Eosin Yellow dye with pH 3, superficial oxygen velocity 2.5 cm/s, applied current density 1 mA/cm2 and three layer of graphite cathode. The degradation rate was found to follow a pseudo-first order reaction kinetics. To assist in the economic evaluation of the two techniques energy consumption was calculated, the electrical energy required for the treatment of 1 m3 of Eosin Yellow dye solution was found to be 15 and 18.88 kW∙h/m3 for UV/H2O2 and photoelectro-Fenton processes, respectively. The cost of chemicals consumed in the UV/H2O2 process should be also considered in comparing the two methods.