Flexibility of Ordered Surface Hydroxyls Influences the Adsorption of Molecules in Single-Walled Aluminosilicate Nanotubes

作者：Zang Ji; Chempath Shaji; Konduri Suchitra; Nair Sankar; Sholl David S^*

来源：Journal of Physical Chemistry Letters, 2010, 1(8): 1235-1240.

DOI：10.1021/jz100219q

Single-walled aluminosilicate nanotubes (NTs) are attractive for molecular separation applications because of their highly ordered structure, tunable dimensions, as well as their hydrophilic and functionalizable interiors. These NTs possess a pore surface consisting of an ordered array of silanol groups with flexible hydroxyls. We show that the flexibility of these hydroxyl groups is critical in the adsorption of hydrogen-bonding molecules. Specifically, we study the adsorption of water, methanol, CO2, and CH4 in the NT via grand canonical Monte Carlo (GCMC) simulations. The experimentally observed hydrophilicity of the surface can be captured in adsorption calculations only if the structural and orientational flexibility of the surface hydroxyls is incorporated. The adsorption selectivity of water over methanol is predicted to be larger than 100, which makes aluminosilicate NTs promising for dehydration of alcohols. Flexibility effects are less significant for the adsorption of non-hydrogen-bonding molecules.

• 出版日期2010-4-15