Surpassing the conventional limitations of CO2 separation membranes with hydroxide/ceramic dual-phase membranes

Abstract We report the development of a dual-phase membrane for CO 2 separation based on a molten hydroxide liquid phase and a nanoporous yttria-stabilized zirconia solid support phase, termed hydroxide/ceramic dual-phase (HCDP) membranes, that can operate in the flue gas temperature range of 250–650 °C. HCDP membranes demonstrate selectivity for CO 2 over N 2 greater than 1000 and CO 2 permeability of 1.78 ± 0.16 × 10 –10 mol m m –2 s –1 Pa –1 (5.32 × 10 5 barrer) at 550 °C with 20 vol% CO 2 , which is more than an order of magnitude greater than the best values for dual-phase and polymer membranes reported in the literature. We also demonstrate using three different experimental methods that CO 2 absorption by molten hydroxides is reversible in the presence of water vapor at temperatures as low as 300 °C.