Kinetic modeling of CO2 adsorption on an amine-functionalized solid sorbent

A kinetic model of CO2 adsorption on an amine-functionalized silica sorbent, 0.37EB-PEI, was proposed by using experimental data from a miniature isothermal fixed bed reactor system called Autochem. Breakthrough curve tests were conducted at different CO2 concentrations and different temperatures to acquire experimental data under adsorption-dominant conditions. Additionally, temperature programmed desorption (TPD) experiments were carried out for different CO2 concentrations with different starting temperatures to investigate the desorption kinetics. A modified Langmuir kinetic equation was found to provide a satisfactory representation of the adsorption-dominant experimental data, including the long tails. A separate kinetic model was proposed to express the desorption-dominant TPD data. The dynamic effects of the empty volume in the Autochem device on the experimental measurements were rigorously handled through separate empty-volume dynamic tests.