The production of ultraclean fuel represents a big challenge for scientists and workers in the petroleum industry because the presence of sulfur in the fuel may have severe consequences for human health and the environment. Oxidative desulfurisation (ODS) is a promising technology when compared with classical hydrodesulfurisation (HDS). In this work, the production of a new catalyst for the ODS process, in which a mixed oxide catalyst was synthesised by mechanochemistry mixing of three metal chlorides (cobalt, nickel, and chromium chlorides), and the atmospheric oxygen was used as an oxidant agent for Iraqi gasoil desulfurisation in an aerobic oxidative desulfurisation (AODS). The prepared catalyst was characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Energy Dispersive X-ray analysis (EDX). The study included an investigation of the effect of catalyst dosage, reaction temperature, and oxidation time. Response surface methodology (RSM) was used to investigate the performance of the AODS reaction and to evaluate the main impact of the studied variables, as well as the interaction and quadratic effects, for determining the optimum condition. According to the findings obtained from the regression analysis, the experimental data were fitted to a quadratic model with a high correlation coefficient (R² 0.9839), adjusted correlation coefficient (Adj. R² 0.9419), and predicted correlation coefficient (Pred. R² 0.7419). The AODS process was applied with a maximum sulfur removal efficiency of 99% under operating conditions of 0.75 g catalyst dosage, 200 °C reaction temperature, and 60 minutes reaction time. The experimental sulfur removal efficiency was in satisfactory agreement with the predicted efficiency of 98.12%. Analysis of variation (ANOVA) shows that oxidation time is the most significant factor affecting sulfur removal efficiency, followed by reaction temperature and catalyst dosage, as indicated by their F-values.
Taha et al. (Mon,) studied this question.