Direct Air Capture of CO with an Amine Resin: A Molecular Modeling Study of the CO Capturing Process.

Several reactions, known from other amine systems for CO capture, have been proposed for Lewatit R VP OC 1065. The aim of this molecular modeling study is to elucidate the CO capture process: the physisorption process prior to the CO-capture and the reactions. Molecular modeling yields that the resin has a structure with benzyl amine groups on alternating positions in close vicinity of each other. Based on this structure, the preferred adsorption mode of CO and HO was established. Next, using standard Density Functional Theory two catalytic reactions responsible for the actual CO capture were identified: direct amine and amine-HO catalyzed formation of carbamic acid. The latter is a new type of catalysis. Other reactions are unlikely. Quantitative verification of the molecular modeling results with known experimental CO adsorption isotherms, applying a dual site Langmuir adsorption isotherm model, further supports all results of this molecular modeling study.