Performance of UV/Persulfate/Ce(IV) process for wastewater treatment in a recycled batch reactor

In this research a new hybridized photochemical oxidation process, named as UV/Persulfate/Ce(IV), has been designed and applied to degrade an organic pollutant, i.e., direct red 16 (DR16) in aqueous media. The process was run in a fully recycled batch photo reactor under mild condition of atmosperic pressure and ambient temperature. Influence of important operational factors such as initial pH of solution as well as initial concentration of persulfate (PS) and cerium(IV) ions were studied. It was found that the PS initial dosage has a strong effect on the degradation efficiency of the DR16. Also, a considarable progress in the chemical oxidation of DR16 was obtained at first min of the process. With respect to the environmental protection point of view related to the concentration of sulfate ions in the aqueous media, low amount of persulfate ions (initial molar ratio of [PS]/[DR16] equal to 25, i.e., 320 mg/l of the potasium persulfate) was used. On the other hand, the photochemical process performance was improved by simultaneous application of small amount of cerium(IV) in molar ratio of [Ce(IV)]/[DR16] equal to 10 (190 mg/l of cerium sulfate). This hybridization was led to a promising result. In the case of hybridized process, the higher efficiency rather than both individual processes is obtained while lower chemicals is added to the media. By the UV/PS(25)/Ce(IV)(10) process about 30% lower consumption of the chemicals is occurred rathe than UV/PS(50), but interestingly higher efficiency is obtained. This result is promising from the applied and economical point of view for the case of running the treatment process in the industrial scale for wastewater effluents.