Assessment of homogeneous hybrid advanced oxidation process for degradation of para-nitrophenol

In this work, degradation and mineralization of para-nitrophenol in the aqueous medium by a mixture of two strong oxidants of persulfate and periodate have been studied. To this aim, a photo-reactor with a volume of 1 L has been used. Optimization and modeling of the process was performed by the response surface methodology. According to the prediction of the model, the process has an ability to remove para-nitrophenol up to 91.6% in the optimal conditions of para-nitrophenol initial concentration of 15 mg/L, [KPS] = 50 mg/L, [KPI] = 49.7 mg/L, and pH = 5 after 40 min. Assessment of the mineralization of para-nitrophenol under optimal conditions showed an efficiency of about 57%, while parallel processes alone (UV and UV/KPS and UV/KPI) showed lower mineralization efficiency. Also, the kinetic study showed that the results were fitted with a pseudo-first-order equation with a regression coefficient of 0.97 and rate constant of 0.052 (L/min). Moreover, the electrical energy consumption for the process was calculated as 110.77 (kWh/m(3)) in the optimum condition. In general, the results of this work showed that the use of the homogeneous hybrid AOP methods increases the efficiency of the mineralization.