Synthesis and Characterization of Dual-Phase Membranes

The combustion of fossil fuels accounts for over a third of total CO2 emissions in the United States. Carbon capture and storage technology is gaining influence as a method of reducing the release of greenhouse gas into the atmosphere. Mixed ionic-electronic conducting (MIEC) dual-phase membranes are in development for selective CO2 separation at high temperatures. The application of these membranes is limited by chemical instability in a CO2-rich atmosphere. Pr0.6Sr0.4Co0.2Fe0.8O3-δ (PSCF) was selected as a potential material for development into a dual-phase CO2 selective disk membrane because of its high oxygen permeation properties and preliminary CO2 stability measurements. Porous supports demonstrated highly repeatable synthesis with an average porosity of 36.9%, He permeance on the order of 10-6 mol·s-1·m-2·Pa-1, and pore diameter of 330 nm. Infiltration with a eutectic mixture of Li2CO3/Na2CO3/K2CO3 resulted in a 16.1% weight gain and reduction in He permeance to 10-9 mol·s-1·m-2·Pa-1. CO2 permeance measurements of the dual-phase membrane were inconclusive due to mechanical failure during heating. XRD, SEM imaging, and EDXS compositional analysis revealed significant strontium carbonate formation on the membranes surface after testing. More thorough CO2 permeance testing of dual-phase PSCF is recommended as the focus of future study.