Study of CO2permeation in Zn2+‐modified Al2O3‐carbonate membrane

Abstract

AbstractMolten carbonate‐based membranes for CO2capture have received attentions because of their high CO2selectivity, potential energy‐saving capability and environmental friendliness. Zn2+‐modified Al2O3/carbonates membranes with the enhanced CO2permeability have been developed in this work. Interfaces of LiAlO2were formed on the surface of Al2O3due to the carbonates incorporation. Microstructural and interfacial characterisation of the membrane revealed that the outermost LiAlO2layer was due to the reactions between Li2CO3and ZnAl2O4, resulting in the dissolution of ZnO in the molten carbonate. CO2permeability of 0.5% ZnAl2O4/Al2O3/carbonates reached 9.12 × 10−12 mol.m−1s−1 Pa−1at 700°C, higher than that of Al2O3/carbonates, because of the dissolved ZnO. With the increase of ZnAl2O4, CO2permeability was decreased. The dissolved ZnO in the molten carbonates could enhance the ionic conductivity, whereas a higher amount of ZnO than its solubility will attenuate its effects on CO2permeation.