Ultraviolet-catalyzed persulfate degradation of cellulosic ethanol wastewater

To study environmental pollution problems, the effects of advanced treatment by an ultraviolet (UV) system, a persulfate (PS) system, and an ultraviolet/persulfate (UV/PS) system on cellulosic ethanol wastewater were compared. The results showed that the UV/PS system had the best removal effi-ciency. When the reaction temperature was 50°C, the initial pH was 6, the dosing of PS was 10 g/L, and the reaction time was 20 h. The maximum removal rate of chemical oxygen demand (COD) was 94.16%, and the effluent COD concentration was 39.6 mg/L. The removal capacity of the system was in accordance with the primary reaction’s kinetic equation. In addition, an optimization analysis of the composite system–degradation of cellulosic-ethanol-reduction in wastewater with alkali + UV-activated persulfate–was conducted. The results showed that the optimum reaction conditions were temperature of 50°C, NaOH dosage of 2 g/L, pH of 6, PS dosage of 6 g/L, and reaction time of 20 h. Under these conditions, the maximum COD removal rate was 97.59%, and the discharge standard of cellulosic ethanol wastewater was met. Therefore, this study can provide a reference for the treatment of cellulosic ethanol wastewater.