Preparation of heteroatomic mesoporous Ce-MCM-41 molecular sieve and its performance in the adsorptive removal of dimethyl sulfide

Heteroatomic mesoporous Ce-MCM-41 molecular sieve was synthesized by using hydrothermal synthesis method with cetyltrimethy ammonium bromide (CTMABr) as template, cerium chloride as cerium source and sodium silicate as silica source. X-ray diffraction (XRD) and infrared spectrum (FT-IR) results indicate that the well-ordered meso-porous structure was obtained when the Ce/Si molar ratio is less than 0.04; Ce was incorporated into the framework of MCM-41. Nitrogen physisorption measurements indicate that the average pore diameters of MCM-41 and Ce-MCM-41 are 2.82 and 2.46 nm, with pore volumes of 0.762 1 and 0.689 4 m³/g and BET surface areas of 986.42 and 756.8 m²/g, respectively. Dimethyl sulfide with a molecular size of 0.464 8 nm can easily enter the meso-scale pores of MCM-41 and Ce-MCM-41. NH₃-TPD results illustrate that the acidity of Ce-MCM-41 is stronger than that of MCM-41. As a result, for the adsorptive removal of dimethyl sulfide from nitrogen with a dimethyl sulfide content of 58 μg/g, the desulfurization capacity of Ce-MCM-41 is 7.52 mg(S)/g, higher than that of MCM-41 (4.57 mg(S)/g). Furthermore, both MCM-41 and Ce-MCM-41 molecular sieves could be easily regenerated after adsorption of dimethyl sulfide; the desulfurization capacity can be recovered up to 80% of the original capacity after regenerated for three times.