Photocatalyst Decolorization of C. I. Sulphur Red 14 From Aqueous Solution by UV Irradiation in the Presence of ZnO Nanopowder

Abstract

Background: Industrial dyestuffs are the main sources of the discharge of dye pollutants into the environment, which are hardly degradable in the conventional biological treatment plants. Therefore, finding an effective method of treatment is urgent for color removal from dye-contaminated effluents. Objectives: In the present study, the photocatalytic degradation of C.I. Sulphur Red 14 was studied by using UV/ZnO process. Materials and Methods: In this work, ZnO catalyst and mercury lamp (UV-C, 254 nm) have been applied for removal of the C.I. Sulphur Red 14 dye from aqueous environments. The influence of various parameters such as the amount of ZnO, initial dye concentration, pH level, and H2O2 presence were also examined. Results: The results showed that the optimum catalyst dose was found to be 50 mg/L. The maximum rate of decolorization was obtained in acidic condition at pH 5 and the initial dye concentration of 10 mg/L. Photodegradation of C.I. Sulphur Red 14 increased by addition of proper dose of hydrogen peroxide. Mineralization of the dye was also investigated as Chemical Oxygen Demand (COD) measurements showed increase in the COD removal with increase in decolorization rate. Conclusions: The UV/ZnO system has been found an effective process with 90.2% COD removal and 95.6% dye removal after 50 minutes treatment.