CO2 CAPTURE OVER MOLECULAR BASKET SORBENTS: INFLUENCE OF THREEDIMENSIONAL MESOPOROUS MATRIX

摘要

CO2 capture and sequestration have attracted great interest in both fundamental research and practical application. Among the new approaches for CO2 capture, amine functionalized sorbents have been shown to be an effective and less-energyintensive approach, as it overcomes the disadvantage of directly using amine aqueous solution. In recent years, we have developed several nano-structured sorbents, called as Molecular- Basket Sorbents (MBS), which are prepared by immobilization of CO2-phillic polyethylenimine (PEI) or oligomer on mesoporous silica materials. Compared to other sorbents, MBS have shown several potential advantages, such as higher capacity (140 mg-CO2/g-sorb at the CO2 partial pressure of 15 kPa), high selectivity, high sorption/desorption rate, and good regenerability and stability. Various mesoporous silica materials, such as MCM-41, SBA-15, MCM-48, and KIT-6, have been investigated for preparation of amine functionalized adsorbents for CO2 capture, giving a CO2 sorption capacity of 111, 127, 119, and 135 mg-CO2/g-sorb, respectively. According to the characteristics of pore structure, the mesoporous silica materials could be classified into 1-D and 3-D mesoporous silica materials. Three dimensional materials are expected to be more attractive and advantageous than those with 1-D or 2-D arrays of pores for adsorption and separation application. Because the material with 3-D pore arrangement could be more efficient for diffusion of CO2 in the CO2-phillic polymer through different directions during sorption/desorption process, and thus may provide more accessible sites for sorption.