Microporous and Mesoporous Materials 22 ( 1998) 281–288 Adsorption of halocarbons on a carbon molecular sieve1 Ravindra K. Mariwala, Madhav Acharya, Henry C. Foley * Center for Catalytic Science and Technology, Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA Received 24 November 1997; received in revised form 24 February 1998; accepted 25 February 1998 Abstract The adsorption isotherms of 16 halocarbons have been obtained in the mid to high range of pressures and at room temperature on a zeolite-like nanoporous carbon molecular sieve Carbosieve G (CSG). All the isotherms display Type I structure in the range investigated. The agreement between the pore volume of the adsorbent calculated based upon the liquid 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 between 4.7 and 7.5 mmol/g. For the larger two-carbon species, C 2 , the adsorption 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 near vicinity of 5 A ˚ are found to predominate, a result which agrees well with pore size determinations made earlier by other means. © 1998 Elsevier Science B.V. All rights reserved. Keywords: Nanoporous carbon; Fluorocarbons; Adsorption isotherms 1. Introduction perform as molecular sieves and do resemble zeo- lites in this respect. This has given rise to a surge The study of microporous, or more properly of research involving these materials as both adsor- nanoporous, structures has enlarged over the last bents and membranes [5–12]. The pioneering work decade to encompass materials that are non-zeo- of Walker and his students laid the foundations litic and even non-crystalline [1–4]. Nanoporous for much of the present-day research in this field carbons (NPC ), called carbon molecular sieves [13]. Shape selective effects at the angstrom level (CMS), are an example of one such class of can and do give rise to adsorptive and catalytic material. Although nanoporous, these materials phenomena which can be exploited for reaction have local order which at best ranges over length and separation technology. At the same time, these scales on no more than 10 to 20 A ˚ . Despite this effects also offer new challenges to the science of lack of long range order, the materials are able to nano-confinement, transport and reaction [14–20]. As a result of its non-crystalline—but regular— * Corresponding author. Fax: +1 302 831 2085; structure, one problem that arises with the NPC E-mail: foley@che.udel.edu that does not arise to the same extent with the 1Dedicated to Professor Lovat V.C. Rees in recognition and zeolite is characterization of the pore structure, appreciation of his lifelong devotion to zeolite science and his outstanding achievements in this field. particularly the pore size distribution. One 1387-1811/98/$19.00 © 1998 Elsevier Science B.V. All rights reserved. PII: S1387-1811(98)00109-7