CO ₂ capture from flue gas using molecular basket sorbents with different supports

CO ₂ capture and storage has attracted great interests in both fundamental research and practical application. Solid amine sorbent has been considered as one of the potential sorbents for CO ₂ capture, which is typically prepared by immobilization of CO ₂-philic polyethylenimine (PEI) or oligomer on a mesoporous material such as MCM-41, SBA-15, MCM-48, KIT-6 etc. In this paper, we report our current progress in improvement of the sorption performance of the molecular basket sorbent (MBS) by using 3-D hexagonal mesoporous silica material (HMS) with wormhole like structure for CO ₂ capture from flue gas. The result showed that HMS-MBS with 50 wt% PEI loading achieved a CO ₂ sorption capacity of 150 mg-CO ₂/g-sorb, which is higher than those of MBS prepared by MCM-41 (90 mg-CO ₂/g-sorb) and SBA-15 (140 mg-CO ₂/g-sorb) with the same PEI loading, although the pore size and pore volume of HMS is quite similar to MCM-41. In addition, the highest CO ₂ sorption capacity of 180 mg-CO ₂/g-sorb was obtained by loading 65% PEI over HMS. The superior CO ₂ sorption capacity of HMS-MBS could be attributed to the special pore structure of HMS, i.e., 3-D wormhole channel motif structure and large textural mesoporosity.