J. Phys. Chem. C 2008, 112, 7717–7724
7717
Adsorption of n-Hexane and p-Xylene in Thin Silicalite-1 Films Studied by FTIR/ATR Spectroscopy Mattias Grahn,*,† Allan Holmgren,‡ and Jonas Hedlund† DiVisions of Chemical Technology and Chemistry, Luleå UniVersity of Technology, SE-971 87 Luleå, Sweden ReceiVed: January 14, 2008; ReVised Manuscript ReceiVed: February 28, 2008
Adsorption isotherms for p-xylene and n-hexane in silicalite-1 films with a thickness of 200 nm were determined at 323, 343, 368, 393, and 423 K using Fourier transform infrared/attenuated total reflection (FTIR/ATR) spectroscopy. For both adsorbates, the low-pressure data agreed with literature data for MFI powder and the estimated Henry’s constant and adsorption enthalpy were close to previously reported results. The upper region of the n-hexane isotherm (p > 2 kPa at 323 K) was likely influenced by micropores in open grain boundaries, as expected for a polycrystalline film of small (
