Synthesis and adsorption properties of micro/mesoporous carbon-foams prepared from foam-shaped sacrificial templates

Foam-shaped, micro/mesoporous, monolithic, carbon materials (carbon-foam) were synthesized by acid-catalyzed polymerization of sucrose solution on selected sacrificial templates. Two different foam-shaped templates that were Polyurethane foam (PUF) and Zeolite foam (ZP), were used to prepare carbon-foam 1 (CP) and carbon-foam 2 (CZ), respectively. Prepared carbon-foams were characterized and studied for their structural and selective adsorption properties. The characterization involved electron microscopy and low-temperature nitrogen adsorption. The carbon-foams demonstrated characteristic cellular structure of foams that verified them as faithful replica of their respective templates. Prepared foams demonstrated specific surface area that varies between 283 and 420 m2 g−1, with hierarchical porosity (involving micro- and mesopores). As a value addition, these foams showed enhancement in compressive strength from their respective templates. High-pressure (up to 103 kPa) adsorption isotherms for CO2, C2H4, and C2H6 gases at highest studied equilibrium pressure revealed that, the order of maximum adsorption was CO2 > C2H4 > C2H6 for each material. Modeling of isotherm data was used to deduce selectivity variation and phase diagram of binary mixture separations, in respect to two important binary mixtures, CO2/C2H6 and C2H4/C2H6. Among other materials the CP was found to be most suitable in terms of separation possibility for both binary mixtures. To assess the competence of these materials in cyclic adsorption systems, their adsorption capacity in terms of working capacity was calculated at two different regeneration pressures (1.0 atm and 1.0 torr).

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► Monolithic shapes of carbon have appropriate transport properties, and stabilities under severe conditions.
► Monolithic shapes of carbon are attractive materials, for applications as adsorptive–separation, catalysis, and sensing.
► Hierarchical pores in these materials are important as macroporosity promotes rapid access to internal porosity.
► Production of hierarchically porous monoliths at industrial scale implies the use of cheap starting materials.
► For the first time sucrose impregnation in Polyurethane and Zeolite foams surface is used for fabricating carbon monoliths.