High CO permeation using a new CeGdO-LaNiO composite ceramic-carbonate dual-phase membrane.

This work shows the synthesis, characterization and evaluation of dense-ceramic membranes made of CeGdO-LaNiO (CG-LN) composites, where the fluorite-perovskite ratio (CG:LN) was varied as follows: 75:25, 80:20 and 85:15 wt.%. Supports were initially characterized by XRD, SEM and electrical conductivity (using vacuum and oxygen atmospheres), to determine the composition, microstructural and ionic-electronic conductivity properties. Later, supports were infiltrated with an eutectic carbonates mixture, producing the corresponding dense dual-phase membranes, in which CO permeation tests were conducted. Here, CO permeation experiments were performed from 900 to 700°C, in the presence and absence of oxygen (flowed in the sweep membrane side). Results showed that these composites possess high CO permeation properties, where the O addition significantly improves the ionic conduction on the sweep membrane side. Specifically, the GC80-LN20 composition presented the best results due to the following physicochemical characteristics: high electronic and ionic conductivity, appropriate porosity, interconnected porous channels, as well as thermal and chemical stabilities between the composite support and carbonate phases.