Kinetic modeling of removal of aromatic hydrocarbons from petroleum wastewaters by UiO-66-NH2/TiO2/ZnO nanocomposite

Abstract

In this study, the UiO66-NH2/TiO2/ZnO (UTZ) nanocomposite was synthesized using the sol-gel method. The mean particle size of UTZ nanocomposite was about 33.63 nm. The present work investigates the applicability of a photocatalytic oxidation process for benzene, toluene and xylene (BTX) degradation. The response surface modeling (RSM) was utilized to optimize important parameters, i.e. catalyst content (g/L), lamp power (W), initial contaminant concentrations and pH. The optimized values of these parameters involved UTZ concentration of 0.11 g/L, lamp power of 15 W, the initial pollutant concentration of 50 ppm and pH= 7. The BTX degradation and total organic carbon (TOC) removal efficiencies were 90.03% and 85.16%, respectively, under optimal conditions. Ultimately, a new kinetic reaction rate model was developed in the form of Langmuir- Hinshelwood equation based on the intrinsic-element reactions in the form of−r=0.102I0.5[UTZ]0.5[BTX]/1+1.9298[BTX]0+1.6059I0.5[UTZ]0.5. The first-order kinetic constant determined by this model was 0.133 min-1. It was observed that the model for the photocatalysis reaction rate was well fitted with the experimental data at minimal mean absolute relative residual (14.18%).