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

Phenol and its derivatives is known as one of the most common pollutants in industrial waste-water. 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 photo -reactor 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 envi-ronmental risk.

Automated summary

Phenol and its derivatives are common pollutants in industrial waste-water. Drinking water with Phenolic compounds can cause systemic poisoning, gastrointestinal damage, skin burns, muscle tremors, and death. A new method combining oxidation and reduction processes (AO/RPs) was used to degrade and mineralize phenol. The UV/SO3/ZnO process had the highest degradation efficiency of 98.8% at 30 min reaction time, 5 mg/L phenol concentration, and pH 11. The results showed that AO/RP had twice the removal efficiency compared to AOP or ARP alone, and the effluent had low toxicity and environmental risk according to toxicity unit (TU<1).