Triamine-grafted pore-expanded mesoporous silica for CO2 capture: Effect of moisture and adsorbent regeneration strategies

Adsorption of carbon dioxide (CO2) was investigated on triamine-grafted, pore-expanded MCM-41 mesoporous silica (TRI-PE-MCM-41). Measurements of adsorption capacity using mass spectrometry showed an enhanced CO2 adsorption capacity in humid streams compared to dry CO2. This was corroborated with breakthrough experiments, which also showed that TRI-PE-MCM-41 offered a practically infinite selectivity towards CO2 over nitrogen. Cyclic measurements of pure CO2 and CO2:N-2 = 10:90 mixture using different regeneration modes showed that amine-grafted PE-MCM-41 is particularly suitable for CO2 removal using temperature swing adsorption (TSA) at adsorption temperatures higher than ambient, while temperature-vacuum swing adsorption (TVSA) may be attractive at ambient temperature.