Adsorptive desulfurization properties of refractory sulfur compounds onto Al2O3-Ga2O3 nanomaterials

Abstract

The impact of the synthesis method on the structural, textural, and surface properties of the Al2O3-Ga2O3 sample was investigated, and the adsorbents were evaluated for their adsorptive desulfurization properties. The incorporation of Ga atoms into the Al2O3 framework (via SGM) resulted in an increase in specific surface area and pore volume, but a decrease in average pore size. XRF analysis confirmed Ga loading, while SEM-EDS and STEM-EDS techniques revealed well-distributed elements with irregular spherical morphologies. XRD diffractograms confirmed the formation of γ-Al2O3, with a slight shift of diffraction peaks due to the presence of Ga (via SGM), suggesting that Ga atoms are part of the structure. The obtained solids exhibit values in the Freundlich equation that indicate a degree of nonlinearity in adsorption for Al2O3, while Al2O3-Ga2O3(SGM) and Al2O3-Ga2O3(IM) suggest a possible chemical process and favorable adsorption. The small KF values demonstrate weak adsorption on the adsorbents, which can be explained by sulfur-to-metal interaction, π-complexation, and non-specific interactions such as Van der Waals forces. The adsorbent showed the greatest affinity for BT and the least for DBT. The selectivity order from strongest to weakest adsorption was BT: Al2O3-Ga2O3(SGM) > Al2O3-Ga2O3(IM) > Al2O3, and DBT: Al2O3-Ga2O3(IM) > Al2O3-Ga2O3(SGM) > Al2O3.