The adsorption of water vapor on carbon fiber composite molecular sieve

Carbon Fiber Composite Molecular Sieve (CFCMS) is a porous adsorbent carbon material manufactured from isotropic pitch derived carbon fibers and a phenolic resin binder via a slurry molding process. The material is produced in the form of a monolith and can be activated in steam, CO{sub 2} or O{sub 2}, during which it develops high BET surface areas and micropore volumes. The material has a continuous carbon skeletal structure and is, therefore, electrically conductive. The passage of an electric current at low voltage allows for direct resistive heating of the carbon and thus provides an efficient method of desorbing adsorbed gases. This method of separating gases has been named electrical swing adsorption (ESA) and is analogous to thermal or pressure swing adsorption. Recently, the authors have examined the potential of CFCMS/ESA for the adsorption and separation of water vapor. Frequently, water vapor must be removed from a gas stream before separation and processing can occur. To assess the potential of CFCMS for water adsorption a series of CFCMS samples were manufactured and activated to relatively high burn-off. Half of each sample was treated at 200 C in flowing oxygen to increase the number of chemisorbed surface functional groups. The amount of water adsorbed has previously been shown to be controlled by the availability of surface functional groups (such as carboxylic acid) which act as active sites for the adsorption of water. Here the authors report the preliminary study of the moisture adsorption behavior of treated and untreated CFCMS samples