For the purpose of process simulation and economic analysis of the proposed CO{sub 2} selective membrane process, we began to generate the equilibrium and rate data at the operating condition interested to our applications. In the last quarter we presented the results obtained at 200 C. In this quarter, we have concentrated on the experiments at 250 C and CO{sub 2} pressure of 0 to 1 bar. In this report we present the equilibrium isotherm and the mathematical treatment using the commonly accepted Langmuir equation. The data fit the Langmuir isotherm well and will be used for future adsorber and membrane reactor modeling. In addition, unsupported hydrotalcite membranes have been successfully synthesized on the silicon wafer with micro-channels. The membrane developed in this quarter ranges 2 to 5 {micro}m in thickness. No visible cracks or defects were observed. Performance characterization of these membranes will begin in the next quarter. Since the interference from substrate in the characterization of the supported membrane is no longer existent, it is hoped that the hydrotalcite membrane thus formed can be optimized for its CO{sub 2} selectivity and performance with the aid of the morphological and performance characterization.