ADSORPTION OF HALOCARBONS ON A CARBON MOLECULAR-SIEVE

The adsorption isotherms of 16 halocarbons have been obtained in the m id to high range of pressures and at room temperature on a zeolite-lik e nanoporous carbon molecular sieve Carbosieve G (CSG). All the isothe rms display Type I structure in the range investigated. The agreement between the pore volume of the adsorbent calculated based upon the liq uid densities of the one-carbon, C-1, halocarbons at room temperature and that determined from the nitrogen adsorption isotherm obtained at 77 K is good. The capacity of CSG for these C-1 molecules ranges betwe en 4.7 and 7.5 mmol/g. For the larger two-carbon species, C-2, the ads orption is lower, in the range from 3.1 to 4.7 mmol/g. A plot of these equilibrium capacities versus the molecule size shows how the extent of adsorption varies with molecule size. The pores with sizes in the n ear vicinity of 5 Angstrom are found to predominate, a result which ag rees well with pore size determinations made earlier by other means. ( C) 1998 Elsevier Science B.V. All rights reserved.