Application of Heterogeneous Catalytic Ozonation Process with Magnesium Oxide Nanoparticles for Toluene Degradation in Aqueous Environments

Abstract

Background: Volatile organic compounds (VOCs) removal like toluene is an important concern for health of humans and the environment. Objectives: In this study, the efficiency of heterogeneous catalytic ozonation process (COP) with MgO nanoparticles for toluene degradation in aqueous solutions was investigated. Materials and Methods: Response surface methodology (RSM) using central composite design (CCD) was applied to study the interactions between critical operating factors and to find their optimum levels. Four independent factors namely pH, catalyst dosage, ozonation time and concentration of toluene were transformed to coded values and consequently a second order quadratic model was prepared for responses prediction. Results: The analysis of variance (ANOVA) of the toluene degradation by COP/MgO nanoparticles showed F-value of 19.53 for the quadratic model indicating that the prepared model is significant. The predicted result showed that maximum degradation of toluene (~99.99%) could be achieved at pH 12, MgO dose 0.5 g, ozonation time of 50 minutes and initial toluene concentration of 10 mg/l. The correlation coefficient (R2 = 0.9480) indicates a good correlation between the experimental and predicted values. Conclusions: According to the results, COP is an efficient and rapid method for removing of toluene from aqueous solutions.