A Model for the Adsorption Kinetics of CO2 on Amine-Impregnated Mesoporous Sorbents in the Presence of Water

A simple model for the adsorption kinetics carbon dioxide onto an amine-impregnated mesoporous sorbent, NETL-32D, was developed. The model was developed based on the mechanistic pathways believed to be responsible for the uptake of CO2 by the sorbent, including interactions with H2O. The model consists of quasi-ideal expressions to describe the kinetics of three reactions responsible for the uptake of CO2 and H2O by the sorbent. The model was fitted to experimental data obtained from thermogravimetric analysis and found to be a reasonable representation of the observed equilibrium and kinetics. The model is able to predict the increased uptake due to the interaction between CO2 and H2O in the sorbent. The heat of reaction predicted by the model for the uptake of CO2 in dry conditions of -65 kJ/mol compares well to the value of -67 kJ/mol obtained via calorimetry for similar sorbents.