Adsorptive Removal of Thiophene by Cu-Modified Mesoporous Silica MCM-48 Derived from Direct Synthesis

A series of Cu-containing mesoporous MCM-48 molecular sieves (Cu-MCM-48) were prepared by the direct synthesis method and used as the adsorbents for desulfurization of model fuel. The samples were characterized by X-ray power diffraction, N-2 adsorption-desorption isotherms, Brunauer-Emmett-Teller specific surface area, transmission electron microscopy, inductively coupled plasma atomic emission spectrometry, and X-ray photoelectron spectroscopy. The results show that the Cu-MCM-48 adsorbent with a copper content up to 10 wt % can still retain the uniform mesoporous framework of MCM-48. The proposed direct synthesis method gives better Cu dispersion and a higher content of active component Cu+ in the support than the conventional incipient impregnation method. As a result, the desulfurization performance of these adsorbents is enhanced. The adsorption behaviors of thiophene on these molecular sieves were measured at 20 degrees C, and their adsorption capacities follow the order 10Cu-MCM-48 > 5Cu-MCM-48 > 10Cu/MCM-48 (synthesized by the incipient impregnation method) > 20Cu-MCM-48. The adsorption isotherms for thiophene fit the Langmuir model well.