Al-MCM-48 as a potential hydrotreating catalyst support: I – Synthesis and adsorption study

The work has been focused on utilizing mesoporous alumina MCM-48 material as a potential hydrotreating catalyst support for light-cycle oil (LCO) and exploring its adsorption ability for large aromatics. A series of Al-MCM-48 samples with various Si/Al ratios was synthesized via a hydrothermal method and characterized with X-ray diffraction (XRD), nitrogen adsorption isotherms, solid NMR, etc. The adsorption equilibrium isotherms of typical aromatics in LCO such as diaromatic 1-methylnaphthalene on Al-MCM-48 and MCM-48 samples were studied by a standard gravimetric technique. Compared with parent MCM-48, Al-MCM-48 samples exhibited higher adsorption capacity and stronger adsorption affinity towards the addressed aromatic compounds. The incorporation of alumina into MCM-48 materials generated acid centers and more hydroxyl groups on the support surface, which can provide enhanced adsorption for the sorbate molecules and dispersion of active phases. It was found that the adsorption behaviors of the aromatic compounds in Al-MCM-48 samples were mainly governed by the acidity of the support. The balance between pore volume and acid strength of Al-MCM-48 can be adjusted by altering Si/Al ratio. The influence of incorporation of Al on the framework and adsorption properties of the materials has also been investigated.