The study focuses on the characterization of Lewatit VP OC 1065, a reference sorbent for direct air capture of \({\hbox {CO}_{2}}\) , for its unary \({\hbox {CO}_2}\) and \({\hbox {H}_{2}\hbox {O}}\) equilibria and sorption kinetics. Unary \({\hbox {CO}_2}\) and \({\hbox {H}_{2}\hbox {O}}\) isotherms were obtained via static measurements and fit to the Toth and Guggenheim-Anderson-de Boer (GAB) isotherm models, respectively. Gravimetric uptake measurements were performed to estimate the sorption kinetics. Lewatit beads were crushed to different sizes to estimate the controlling resistance for \({\hbox {CO}_2}\) sorption. It was found that a portion of the resistance lies in the macropores of the sorbent, while the other is likely related to reaction kinetics. A series of micro-scale dynamic column breakthrough experiments was performed to evaluate equilibrium and kinetic parameters. The linear driving force (LDF) coefficient estimated for 400 ppm \({\hbox {CO}_2}\) at T = 30 \(^{\circ }\) C via gravimetric and breakthrough experiments were \(3.7\times 10^{-4}~{\textrm{s}^{-1}}\) , and \(2 \times 10^{-3}~{\textrm{s}^{-1}}\) , respectively. Similarly, for \({\hbox {H}_{2}\hbox {O}}\) at 15% relative humidity and \(30^{\circ }\) C, the LDF coefficient from gravitmetric and breakthrough experiments were \(3.38\times 10^{-3}~{\textrm{s}^{-1}}\) , and \(7.0\times 10^{-2}~{\textrm{s}^{-1}}\) , respectively. We postulate that this difference in LDF coefficients might be due to the unreliability of the sensors in detecting low compositions. Breakthrough experiments conducted suggest that the sorption kinetics increase with an increase in \({\hbox {CO}_2}\) composition and temperature.
