Treatment of a textile wastewater using sulfate and hydroxyl radicals based oxidation under the uv light: a comparison between uv/h2o2, uv/ps and uv/pms

Abstract

In this study, chemical oxygen demand (COD), total organic carbon (TOC) and color removal efficiencies and treatment costs were compared with three different oxidation processes using hydroxyl or sulfate radicals in a textile wastewater. UV/H2O2 process was used to obtain hydroxyl radicals, UV/PS and UV/PMS were used to obtain sulfate radicals. Optimum catalyst concentrations and optimum pH values were determined for all three processes by investigating COD, TOC and color removal efficiencies. According to the results, the highest removal efficiencies were obtained under the optimal conditions of pH: 7 in UV/PS oxidation, pH: 8 in UV/PMS oxidation, and pH 4 in UV/H2O2 oxidation. The COD, TOC and color removal efficiencies were obtained as 85.5%, 65.7% and 99.0% in UV/PS oxidation (COD/PS: 1/5, pH: 7) and 81.8%, 70.3% and 96.7% in UV/H2O2 oxidation (H2O2: 1750 mg/L, pH: 4), respectively. The COD, TOC and color removal efficiencies were 65.9%, 37.3% and 98.8% in UV/PMS oxidation (COD/PMS: 1/10, pH 8), respectively. UV/PMS oxidation was sufficient in terms of color removal, but not satisfactory in terms of organic matter removal. The order of performance of the processes was as follows: UV/PS>UV/H2O2>UV/PMS. The ranking according to total cost was as follows: UV/PS