Abstract
More effective and convenient methods for scrubbing carbon dioxide from gas streams are required for a range of applications, from purification of air to removal of carbon dioxide from fuel and syngas streams for fuel cells. In this paper, recent results on the development of three-dimensional carbon fiber composite molecular sieve (CFCMS) material as a selective, regenerable adsorbent for removing CO2 (and other small molecules) from air and other gas streams will be presented. CFCMS is a contiguous monolithic carbon structure that can be activated to various levels for tunable adsorption properties, and can be regenerated through a combination of pressure swing and resistive heating. Dynamic breakthrough data for CO2 separation from air were analyzed and expressed in terms of a simple kinetic model (Yoon-Nelson). It was demonstrated that predictions made on the basis of the model can be extrapolated over a broad range of influent CO2 concentrations and flow rate conditions. In addition to reducing CO2 concentrations in air, e.g., from tens of percents levels to a few ppm levels, CFCMS material can also be tailored for the rapid removal of air borne molecular contaminants, odor control, and personnel protection (respirators). The CFCMS adsorbent can be efficiently regenerated by a combination of resistive heating and gas purge.
