Post-synthesis and adsorption properties of interlayer-expanded PLS-4 zeolite

PLS-4 lamellar precursors, comprised of FER layers and organic structure-directing agent of diethyldimethylammonium cations, were interlayer expanded by silylation with Me2Si(OEt)2 molecules, yielding PLS-4-sil materials with a larger porosity than directly calcined PLS-4 with the CDO topology. The silylation conditions were optimized to obtain a highly ordered interlayer-expanded structure. The silylation introduced about four additional silicon atoms per unit cell to pillar the FER layers. The silicon insertion not only widened the interlayer entrance but also endowed the inorganic zeolite with organic functionality by introducing two methyl groups per silane molecule. As an organic–inorganic hybrid material, PLS-4-sil possessed changeable pore openness and hydrophilicity/hydrophobicity after controlled removal of methyl groups by calcination. Coherently, its adsorption capacities varied with calcination temperature for the adsorption of water, n-hexane and benzene molecules.

Figure optionsDownload as PowerPoint slideHighlights
► Interlayer expanded zeolites were prepared by silylation of PLS-4 lamellar precursor.
► The silylation conditions were optimized to achieve a well ordered expanded structure.
► The pore opening and hydrophilicity/hydrophobicity were controlled by calcination.
► Interlayer expanded PLS-4 exhibits unique adsorption properties.