Synthesis of Organically Inorganically Functionalized MCM-41 for Adsorptive Desulfurization of C4 Hydrocarbons

A series of organically inorganically-functionalized MCM-41 compounds have been prepared with 3-aminopropyltrimethoxysilane (APTMS) as the organic component and CuO and/or Cu(NO3)(2) as the inorganic component. The textural properties of functionalized MCM-41 were characterized by powder X-ray diffraction (XRD), nitrogen adsorption-desorption, and transmission electron microscopy (TEM). The results indicate that the hexagonally ordered structure of MCM-41 remained intact after functionalization. The presence of grafted organosilanes was confirmed by Fourier transform infrared (FTIR) spectra, C-13 nuclear magnetic resonance (C-13 CP-MAS NMR), and Si-29 nuclear magnetic resonance (Si-29 MAS NMR). All adsorbents showed similar desulfurization performances for different sulfur compounds in the order tert-butyl mercaptan (TBM) > dimethyl sulfide (DMS) > dimethyl disulfide (DMDS), which is due to the poor reactivities and polarities of DMS and DMDS. MCM-41-NH2-Cu functionalized with Cu2+ as the active sites is the most efficient adsorbent for the removal of TBM. The desulfurization mechanism was discussed based on the experimental results and X-ray photoelectron spectroscopy (XPS) characterization. The results show that CuO plays a more dominant role than Cu2+ for the removal DMS and DMDS.