Desulfurization of Liquid Hydrocarbon Streams via Adsorption Reactions by Silver-Modified Bentonite

Removal of organic sulfur compounds from its solution has been investigated by using adsorption. The purpose of this study is to investigate the removal of dimethyl disulfide (DMDS) in liquid hydrocarbon streams with bentonite modified by Ag+. The addition of Ag+ on the bentonite significantly enhanced the adsorption capacity of DMDS. The adsorbents were characterized by nitrogen adsorption, X-ray diffraction (X), and thermal analysis (TGA). Fourier transform infrared (FT-IR) spectroscopy showed that the type and number of surface acidic sites on the adsorbents could increase the adsorption capacity. Several factors that influence the desulfurization capability, including loading, reaction temperature, and calcination temperature, were studied. The maximum sulfur adsorption capacity was obtained at a silver loading of 6 wt %, and the optimum calcination temperature was 150 degrees C. Spectral shifts of the v(C-S), v(S-S), and v(Ag-S) vibrations of the complex compound obtained by the reaction of Ag+ and DMDS were measured with the Raman spectrum. On the basis of complex adsorption reaction and hybrid orbital theory, the adsorption on modified bentonite occurred via multilayer intermolecular forces and S-M (sigma) bonds.