| abstract |
The present invention relates to an adsorbent formed by the pyrolysis of a hydrophobic silica with a pore size greater than 5 ANGSTROM , such as SILICALITE TM , with a molecular sieving polymer precursor such as polyfurfuryl alcohol, polyacrylonitrile, polyvinylidene chloride, phenol-formaldehyde resin, polyvinylidene difluoride and mixtures thereof. Polyfurfuryl alcohol is the most preferred. The adsorbent produced by the pyrolysis has a silicon to carbon mole ratio of between about 10:1 and 1:3, and preferably about 2:1 to 1:2, most preferably 1:1. The pyrolysis is performed as a ramped temperature program between about 100 DEG and 800 DEG C., and preferably between about 100 DEG and 600 DEG C. The present invention also relates to a method for selectively adsorbing organic molecules having a molecular size (mean molecular diameter) of between about 3 and 6 ANGSTROM comprising contacting a vapor containing the small organic molecules to be adsorbed with the adsorbent composition of the present invention. |