Experimental and theoretical study of deep oxidative desulfurization of Dibenzothiophene using Oxalate-Based catalyst

Abstract

The present study reports the experimental and theoretical investigation for production of ultra-low sulfur liquid fuels through estimation of various reactive species formed during the reaction with the help of simulation. All the experiments were performed using an ultrasound bath which operates at a frequency of 37 kHz and a theoretical power of 95 W. The presented oxalate-based technique is found to be more efficient with > 93% DBT oxidation within 15 min of reaction time at 25 °C due to formation of reactive species like FeIIC2O4 and FeIIC2O422- which accelerate the reaction kinetics. Moreover, we have also investigated the influence of process parameters such as molar ratio of C2O42-/Fe2 +, oxidant concentration, volume ratio of organic to aqueous phase, sulfur concentration, and activation methods of oxidant. The results revealed that catalyst can be reused for several runs without decrease in catalytic activity. The experimental and simulation of cavitation bubble dynamics results revealed that sonochemical effect assists to accelerate the reaction kinetics through formation of free radicals (•O, •H, •OH and HO2∙) and other reactive species like O3 and H2O2 generated during transient cavitation. The sono-physical effects of cavitation help to create a fine emulsion in the liquid–liquid heterogeneous system leading to enhanced mass transfer rate by providing more interfacial surface area for occurring chemical reaction.