Deep Desulfurization by the Adsorption Process of Fluidized Catalytic Cracking (FCC) Diesel over Mesoporous Al−MCM-41 Materials

Al−MCM-41 adsorbents with different SiO 2 /Al 2 O 3 molar ratios (100, 50, and 30) were synthesized and used for desulfurization of a commercial diesel fuel (sulfur content = 1786 ppmw) at 373 K. The adsorbents were characterized by means of X-ray diffraction, N 2 adsorption isotherm, Fourier transform infrared, and high-resolution transmission electron microscopy techniques. The adsorption capacity for sulfur-containing compounds was found to follow the order: Al−MCM-41(50) > Al−MCM-41(30) > Al−MCM-41(100) (the number in parentheses is the SiO 2 /Al 2 O 3 ratio hereafter). The efficiency of sulfur removal is 95% over Al−MCM-41(50) at the initial state and still above 75% after a cumulative effluent volume of 17 mL. The effect of the adsorption temperature on the adsorption capacity of Al−MCM-41(100) was investigated. The results indicate that high temperature is disadvantageous for desulfurization. After the regeneration of a spent Al−MCM-41(100) sample (calcined at 823 K for 6 h), there is good recovery of the adsorption capacity. In addition, with the presence of Cu + ions in Al−MCM-41, there is enhancement in the adsorption capacity and sulfur removal efficiency at 373 K and the effect can be related to the formation of π complexation between sulfur-containing compounds and Cu + ions.