CeO-Blended Cellulose Triacetate Mixed-Matrix Membranes for Selective CO Separation.

Due to the high affinity of ceria (CeO) towards carbon dioxide (CO) and the high thermal and mechanical properties of cellulose triacetate (CTA) polymer, mixed-matrix CTA-CeO membranes were fabricated. A facile solution-casting method was used for the fabrication process. CeO nanoparticles at concentrations of 0.32, 0.64 and 0.9 wt.% were incorporated into the CTA matrix. The physico-chemical properties of the membranes were evaluated by SEM-EDS, XRD, FTIR, TGA, DSC and strain-stress analysis. Gas sorption and permeation affinity were evaluated using different single gases. The CTA-CeO (0.64) membrane matrix showed a high affinity towards CO sorption. Almost complete saturation of CeO nanoparticles with CO was observed, even at low pressure. Embedding CeO nanoparticles led to increased gas permeability compared to pristine CTA. The highest gas permeabilities were achieved with 0.64 wt.%, with a threefold increase in CO permeability as compared to pristine CTA membranes. Unwanted aggregation of the filler nanoparticles was observed at a 0.9 wt.% concentration of CeO and was reflected in decreased gas permeability compared to lower filler loadings with homogenous filler distributions. The determined gas selectivity was in the order CO/CH > CO/N > O/N > H/CO and suggests the potential of CTA-CeO membranes for CO separation in flue/biogas applications.