FAU-Type Zeolite Nanocasted Carbon Replicas for CO2 Adsorption and Hydrogen Purification

Microporous ordered carbon have been synthesized by the nanocasting process from zeolite Y using acetylene and furfuryl alcohol as carbon precursors. If the proper synthesis conditions are chosen, these materials retain the long-range order of the zeolite mold. The resulting carbons possess a large surface area (>= 2200 m(2)/g), a high microporosity (>= 1.0 cm(3)/g), and a controlled pore size distribution, which was tailored by the wall thickness of the zeolite template. Because of their high micropore volume, the carbon replicas of zeolite Y are attractive adsorbent materials and might be used to replace conventional activated carbons as adsorbents in pressure swing adsorption processes (PSAs) for H-2 purification. In the present contribution, we evaluate the adsorption capacity of the carbon replicas in a H-2-PSA based on their single-component adsorption isotherms of CO2, CH4, and N-2 measured at room temperature. The ideal adsorbed solution theory (IAST) was used to predict the co-adsorption of CO2/CH4/N-2 vas mixtures and to evaluate the working capacity of the materials under typical operating conditions of a H-2-PSA process. The comparison of the working capacities shows that the carbon replicas largely outperform conventional activated carbons while having comparable CO2/CH4 and CO2/N-2 selectivity.