Isotherm and kinetics modeling of simultaneous CO2 and H2O adsorption on an amine-functionalized solid sorbent

Isotherm and kinetic models of CO2 adsorption on an amine-functionalized silica sorbent, SiO2/0.37 EB-PEI, in humid conditions is proposed through experiments in a fixed bed reactor. The proposed isotherm model is derived through as equilibrium reaction mechanism and can simultaneously express competitive adsorption of H2O and CO2 and adsorption by bicarbonate formation. Breakthrough curve tests were conducted at different values of CO2 and H2O partial pressures (CO2 = 2.5, 5, and 15 kPa & H2O = 2.5 and 3.75 kPa) and temperatures (313, 328, and 343 K) in the adsorption-dominant region, and the data were regressed to a rigorous fixed-bed model. Kinetic models were derived from the reaction mechanism forming carbamate and bicarbonate, and model parameters were estimated using experimental data. Langmuir-type kinetic models with parameters expressed as functions of CO2 partial pressure, H2O partial pressure, and temperature could successfully represent CO2 adsorption on the amine-functionalized solid sorbent.