Desulfurization of Real Diesel Fuel onto Mesoporous Silica MCM-41 Implementing Batch Adsorption Process: Equilibrium, Kinetics, and Thermodynamic Studies

Abstract

In the current work, sulfur was removed from actual diesel fuel containing 1.2 wt.% sulfur from the Al-Dura Oil Refinery (Iraq), which was studied using adsorption desulfurization with the spherical mesoporous silica MCM-41. This study investigated the effects of different operating conditions, including the dose of MCM-41 (0.04-0.2 gm), time (60-180 min), and temperature (30-70°C). The optimal working conditions were determined to be 0.4 gm MCM-41, 180 min, and 70°C. After exploring the isotherm models of Langmuir, Freundlich, and Temkin, Temkin models with a correlation coefficient (R2 = 0.9996) were selected to best represent the stable data. The kinetics of sulfur components on MCM-41 were studied using pseudo-first-order and pseudo-second-order kinetic models and intra-particle diffusion. A pseudo-first-order adsorption kinetic model with a correlation coefficient (R2) of 0.9867 can accurately represent the adsorption process. Gibbs free energy (ΔGo), enthalpy (ΔHo), and entropy (ΔSo) were calculated as thermodynamic parameters. The adsorption of total sulfur-containing compounds onto mesoporous silica was spontaneous, endothermic, and increased the irregularity of the sulfur compounds on the surface of the adsorbent. The total sulfur content of actual diesel fuel was reduced from 1.2% to 0.84%, corresponding to a desulfurization efficiency of 29.72%. Consequently, the findings of this study might be used as a starting point for future research.