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, N₂ 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 °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.