Parametric and laboratory aging studies of direct CO2 air capture simulating ambient capture conditions and desorption of CO2 on supported alkaline adsorbents

Abstract

Alkali and alkaline earth metal oxides dispersed on high surface area γ-alumina were studied for the selective adsorption of CO2 under simulated ambient direct air capture (DAC) and subsequent temperature programmed desorption. Thermogravimetric analysis showed Na2O/γ-Al2O3 had superior adsorption and desorption via temperature programed desorption (TPD) relative to other supported metal oxides. Parametric and laboratory aging studies were conducted under simulated direct air capture of 400 ppm CO2, reflecting seasonal and locational ambient temperature and humidity conditions. Initial studies were performed on granular carriers and subsequently on washcoated ceramic monoliths. Aging studies were conducted on sample compositions of 10% Na2O/γ-Al2O3 granules and 10% Na2O + PX-80 γ-Al2O3 washcoat, deposited on a cordierite automotive-catalytic converter type monolith designed for low pressure drop in high air flow rates. Both selective adsorption and desorption of CO2 showed high stability with no signs of deactivation after 400+ hours of cyclic testing under a wide variety of simulated ambient conditions.