(226e) Designing Sorption-Enhanced Mixed Matrix Membranes for H2/CO2 Separation Using an Integrated Experimental and Modeling Approach
Membrane technology is an energy-efficient and low-cost approach for pre-combustion CO2 capture and H2 purification in the integrated gasification combined cycle (IGCC) processes. Conventional membranes are based on rigid polymers with strong size sieving ability, such as poly[2,2â-(m-phenylene)-5,5â-bisbenzimidazole] (PBI) that provides high H2/CO2 diffusion selectivity. In this study, we demonstrate enhanced H2 sorption and diffusion in PBI films with embedded palladium (Pd) nanoparticles, which have strong affinity towards H2. Pd nanoparticles with uniform diameters of 6 - 8 nm are prepared via a hot-injection colloidal synthesis. The loading of Pd nanoparticles in PBI increases H2 sorption by almost 1,000 times, and at high Pd loadings, the Pd nanoparticles may form fast channels allowing the H2 molecules to jump from one particle to another and thus increasing the effective H2 diffusivity. For example, adding 58 wt.% Pd in PBI increases H2 permeability from 25 to 60 Barrers, and H2/CO2 selectivity from 13 to 34 at 175 Â°C. Such performance is above the Robesonâs upper bound for H2/CO2 separation, demonstrating the potential of these new materials for industrial H2/CO2 separation. The gas transport in these PBI-Pd nanocomposites is being modeled using computational fluid dynamics (CFD) to elucidate the mechanisms for the facilitated H2 transport. This presentation will also discuss the visualized microstructure of the nanocomposites and provide a unified view of the H2 and CO2 transport in the nanocomposites using an integrated experimental and simulation approach.