Monitoring Solid Oxide CO 2 Capture Sorbents in Action

The separation, capture, and storage of CO 2 , the major greenhouse gas, from industrial gas streams has received considerable attention in recent years because of concerns about environmental effects of increasing CO 2 concentration in the atmosphere. An emerging area of research utilizes reversible CO 2 sorbents to increase conversion and rate of forward reactions for equilibrium‐controlled reactions (sorption‐enhanced reactions). Little fundamental information, however, is known about the nature of the sorbent surface sites, sorbent surface–CO 2 complexes, and the CO 2 adsorption/desorption mechanisms. The present study directly spectroscopically monitors Na 2 O/Al 2 O 3 sorbent–CO 2 surface complexes during adsorption/desorption with simultaneous analysis of desorbed CO 2 gas, allowing establishment of molecular level structure–sorption relationships between individual surface carbonate complexes and the CO 2 working capacity of sorbents at different temperatures.