nanoporous materials, CO2 capture, adsorption capacity, adsorption selectivity, deactivation pathways
Amine-containing nanoporous materials gained tremendous popularity in recent years as adsorbents for CO2 removal. When properly designed, amine-functionalized materials exhibit high adsorption capacity, fast CO2 adsorption and desorption, and low-energy requirements for recycling compared to amine solutions. Although work in this area has been extensive, particular in the last 5-6 years, the literature is dominated by measurements of equilibrium and near equilibrium CO2 uptake using simple gas mixtures, without the typical impurities found in industrial gases. Not only little attention was devoted to adsorption and desorption kinetics, but long-term stability of the adsorbent even in the presence of simple gas mixtures has been rarely addressed. This work summarizes our multifaceted studies dealing with the following issues (i) importance of the pore size volume and length, (ii) optimization of amine-grafting conditions, (iii) CO2 adsorption capacity and rate, (iv) tolerance to moisture in the feed, (v) selectivity toward CO2 vs. other adsorbates such as N2, O2, H2, CH4, H2S, and SO2 and (vi) adsorption-desorption cycling, (vii) stability of the adsorbent in the presence of moisture, (viii) oxidative degradation, and (ix) dry CO2-induced deactivation and mitigation thereof.