Using solid sorbents to selectively capture CO 2 from various gas streams, especially from flue gas, is of critical importance in mitigating the greenhouse gas emissions, and is a promising alternative because of its great potential in lowering energy requirements for regeneration and operation, and the cost for the CO 2 separation process due to smaller process equipment, less expensive materials of construction, and inexpensive raw materials. In the past years, we have developed a novel sorbent material on the basis of molecular basket concept, so-called molecular basket sorbent (MBS). The sorbent has shown some potential advantages including high sorption capacity, high selectivity, fast CO 2 sorption/desorption kinetics, easy regeneration and positive effect of moisture. However, the CO 2 sorption mechanism over MBS is still not clear. As a continuous work, the present paper will report our current efforts and progress in the study of the fundamentals on CO 2 sorption mechanism over MBS material by using in-situ FT-IR, CO 2 temperature-programmed desorption method (CO 2-TPD) and the computational simulation. Through the study, two sorption species, surface carbamate species and chemically sorbed CO 2 molecules within the sorbent bulk have been recognized by in-situ FT-IR. And two desorption stages, i.e. for the desorption of carbamate species and chemically sorbed CO 2 molecules, and two sorption regions, i.e. kinetically and thermodynamically controlled regions in CO 2 sorption over PEI/SBA-15 have also been identified and clarified. The CO 2 sorption mechanism over MBS has consequently been proposed.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)