Photocatalytic Decolorization of Uranine Using UV/S2O8 and UV/H2O2 Processes from Aqueous Solutions: A Laboratory Study

The entry of textile mills’ wastewater into the environment causes severe disruption to aquatic environments. Thus, the aim of this study was to compare the performance of processes of UV/ S2O8 and UV/H2O2 in removal of Uranine dye from aqueous solutions. In this laboratory study, in a batch reactor, the efficiency of UV/S2O8 and UV/H2O2 photocatalytic methods in removing the dyes of Uranine from aqueous solutions was investigated. In this study, a UV-C low pressure mercury lamp covered by quartz and 150 W was used inside a steel chamber with a high degree of reflection. The pH variables (3-5-7-9 and 11), the concentration of hydrogen peroxide (10-15-20-30 and 50 Mmol/l), the concentration of persulfate (0.1-0.5-1-1.5 and 2 Mmol/l) and primary dye concentrations (10-25-50-75 and 100 mg/l) were optimized. The highest removal efficiency (100%) was attained by UV/S2O8 process under the optimized conditions as follows: pH 3, persulfate concentration 2 Mmol / L, Uranine concentration 10 mg/L and contact time of 5 min, but, by UV/H2O2 process the same amount of dye was removed in the optimal conditions of pH = 3, the hydrogen peroxide concentration 20 Mmol / L, Uranine concentration 10 mg/L and contact time of 2.5 min. According to the results, the methods used to remove the mentioned paint in the wastewater have a 100% efficiency. Also, the catalyst concentration and reaction time variables have a more effective role in the removal efficiency than the other parameters.