Enhanced dual phase membranes for separating carbon from carbon-containing feed gases and separation methods using the same

Abstract

Dual phase membranes include a porous support providing a solid phase having a matrix of connected pores, and a liquefiable ion transport phase within the pores of the porous support. The ion transport phase is formed of at least one alkali metal hydroxide, and at least one oxide ion transport agent providing a source of ions selected from the group consisting of borate ions, nitrate ions, phosphate ions, vanadate ions, niobate ions or sulfate ions. The at least one alkali metal hydroxide may be selected from the group consisting of NaOH, KOH, LiOH, RbOH, CsOH and mixtures thereof. The oxide ion transport agent is preferably present in the ion transport phase in an amount between about 1 to about 30 molar %. Substantially lower operational temperatures may be realized when the membrane is used to separate CO2 from a feed gas.