Evaluation of phenol degradation rate using advanced oxidation/reduction process (AO/RP) in the presence of sulfite and zinc oxide under UV

Abstract

Phenol and its derivatives is known as one of the most common pollutants in industrial wastewater. Drinking water containing Phenolic compounds can cause systemic poisoning, serious gastrointestinal damage, skin burns, muscle tremors, and death. Since phenol is not removed by conventional wastewater treatment methods, hybrid methods are needed. Therefore, in the present study, two processes of oxidation and reduction (AO/RPs) were combined in a photoreactor as a new method, so that oxidizer and reducer agents simultaneously degrade and mineralize phenol. Degradation efficiency of the UV-only, UV/ZnO, UV/SO3 and UV/SO3/ZnO processes were obtained as 27%, 59.24%, 77.93% and 98.8% respectively, at 30 min reaction time, 5 mg/L phenol concentration and pH 11. According to the results obtained, 0.3 g/L ZnO dose and 1.5 mg/L SO3 were the optimal values in phenol degradation. GC-MS analysis showed that within 30 min, phenol was converted to simpler linear hydrocarbons, however more time was required for complete mineralization. In general, the removal efficiency of AO/RP was twice as high as the AOP or ARP alone. According to the results obtained from the toxicity unit (TU<1), it can be concluded that the toxicity of the effluent from AO/RP was low and has a low environmental risk.