Development of K and N based composite CO2 sorbents (KN) dried with a supercritical fluid

The objective of this research was to develop composite CO2 sorbents for overcoming the shortcomings of the corresponding individual sorbents. The composite sorbents were synthesized with K2CO3, 3-aminopropyltriethoxysilane (APTES), tetraethylorthosilicate (TEOS) and dried either with supercritical or conventional technique. Comparative experiments demonstrated that supercritical fluid drying (SCFD) was better than conventional drying (CD) in preparing CO2 sorbents with more developed pore structure and thus higher CO2 sorption capacity. The composite sorbent prepared with SCFD was tested under various conditions for their effects on CO2 sorption capacity. The optimal K:N mole ratio for preparation of the composite sorbent and the reaction conditions for achieving the highest sorption capacity were obtained. In addition, the sorbent proved to be regenerable. Thus, supercritical drying is an effective technique for preparation of a promising composite CO2 sorbent.