Preparation Of Nitrogen - Rich Carbon - Based Microporous Materials And Their Physical Adsorption Properties Of CO 2

Carbon-based microporous materials attract great interests because of their unique composition structure, high specific surface area, narrow pore size, high physical chemical and mechanical stability as the most promising candidates for CO2 adsorption and separation. The microporous volume, pore size, heat of adsorption and stability can affect the physical adsorption properties of CO2 and CO2/N2 selectivity.We synthesize a series of MR polymer microspheres with an extended network via a hydro-thermal method using melamine(M), formaldehyde(F), resorcinol(R) as precursors. A series of nitrogen enriched microporous carbons have been prepared by direct KOH activation of melamine-doped phenolic resins. In this work, we primarily investigated the ratio of M/R(1:1-3:1) and effect of activation temperature(500-700oC) on the BET specific surface area and micropore volume of microporous carbon material. Further studied was carried on the relationship of N content, activation temperature and CO2 capture and CO2/N2 selectivity.The activated carbons show high CO2 uptakes up to ca. 1.3 mmol/g under low pressure(0.15 bar, 25oC), which can be ascribed to not only their optimal fraction of ultramicropores but also the high N-contents. One of the samples even exhibits excellent adsorption selectivity for CO2 over N2(i.e., selectivity factors of 43.7 and 52.9 obtained from initial slope and IAST calculations, respectively). Furthermore, the preferential CO2 uptake of the carbons was confirmed by successive breakthrough experiments under post combustion flue gas stream conditions(15% CO2 concentration, 1 bar and 25oC). Since these carbons also feature good stability over repeated thermal cycling and ease of regeneration, their practical applications in post combustion CO2 capture shall lie within the realm of possibility.