| This work presents the synthesis and characterization of a novel adsorbent and the development of a modified method for pore size characterization of microporous adsorbents. In the first part, a novel adsorbent is developed by polymerization and carbonization of monomer, either acrylonitrile or furfuryl alcohol, in the channels of a host material. The substrate used is MCM-41, a mesoporous silica with long range order, with one-dimensional, hexagonal channels. The results show that the polyfurfuryl alcohol (PFA) yields carbon loadings closer to the theoretical value than the polyacrylonitrile (PAN). Encapsulation of polyfurfuryl alcohol (PFA) results in a variety of adsorbents with either mesoporosity or microporosity, or a combination of both. The microporous PFA carbon-MCM adsorbents exhibit a narrow pore size distribution. Isotherm data indicate that the PFA carbon in the pores is activated and possesses a high surface area. In addition, a change in the impregnation time and carbonization temperature affects the evolution of carbon in the pores, thereby changing the adsorption properties.;The other part of this work focussed on modifying the HK method to provide a single pore size distribution for a given adsorbent using different probe molecules. The probes used in this study are argon, xenon, nitrogen, carbon dioxide, methyl chloride, and ammonia, while the adsorbents are BPL carbon and silica gel. The original HK method is not sufficient to give consistent results for all of the probes. It underpredicts or overpredicts the pore potential in some cases. A parametric study indicated that the use of an optimized set of parameters including adsorbate density would serve to collapse the pore size distributions together. The modifications to the HK method accounted for the additional electrostatic and induction forces resulting from the polar nature of the probes. However, like the original HK equation, the modified HK equation does not provide a unified model for pore structure description. Results indicate that coupling of one or more of the effects studied would provide consistent results for all of the probes on a given adsorbent. Recommendations have been made for the use of each probe within the framework of the HK method. |
