To become a viable CO{sub 2} transport membrane, a reversible interaction between CO{sub 2} and the membrane material at the operating condition is a must. In the past quarter, we have conducted a comprehensive reversibility study using TGA and MS at {approx}200 C for both adsorption and desorption. This quarterly report summarizes the results. Evidently, CO{sub 2} can be reversible adsorbed and desorbed on the hydrotalcite surface via a pressure swing operation (i.e., between 1 bar and vacuum). About 2wt% working capacity was obtained. Even in the presence of water, the reversibility still holds. In the next quarter, we will focus on the reversibility under other operating conditions and the kinetic aspect of the reversibility study.

In this quarter, we have made progress in the three approaches selected for preparing CO{sub 2}-affinity membrane. A defect free nanoporous membrane was prepared via slip casting. This membrane will then be used for post treatment to seal the micropores to become a non-porous membrane with CO{sub 2} affinity. This post treatment study will be our focus in the next several quarters. Polymeric gel as a precursor was successfully prepared, which will be used for subsequent thin film deposition. Preparation of a defect-free thin film from this precursor will be our future focus using the sol-gel approach. Finally, the third approach, in-situ impregnation approach, was modified. Although we were able to deposit the precursor within the porous of the membrane, we have not been able to enhance the pH in-situ. Designing an unconventional approach to alternate the pH in-situ will be our focus of the next quarter.