Effect of Water on the CO2Adsorption Capacity of Amine-Functionalized Carbon Sorbents

Abstract

Molecular simulation is used as a tool to improve understanding of CO2 adsorption in nitrogen-functionalized carbon sorbents in the presence of water vapor, which is crucial to the advancement of adsorption approaches to CO2 separation from exhaust streams of coal- and natural gas-fired power plants. Molecular simulations were carried out for binary mixtures of CO2 and H2O over four N-functionalized surfaces and three variations of the quaternary group with increasing wt % N. The quaternary group was found to be most stable with a 13% loss in CO2 capacity observed, followed by the pyrrolic and pyridonic groups, which lost 25 and 28% CO2 loading capacity, respectively. The oxidized pyridinic group demonstrated a dramatic loss in capacity, i.e., 58% when compared to ideal loading. The quaternary group was the only functionality to display loading in excess of 2.0 mmol CO2 g–1 sorbent under ambient temperature and 1% humidity (2.40 mmol CO2 g–1 sorbent). Further, the two functional groups without oxygen were...