(401w) Sorption Enhanced Mixed Matrix Materials Comprising Palladium Nanoparticles and Polybenzimidazole for H2/CO2 Separation
Polymeric membranes have been widely explored for energy-efficient and low-cost CO2 capture and H2 purification in the integrated gasification combined cycle (IGCC) processes. Conventional approaches are focused on designing rigid polymers with strong size sieving ability achieving high H2/CO2 diffusivity, such as poly[2,2â-(m-phenylene)-5,5â-bisbenzimidazole] (PBI). In contrast, we investigate mixed matrix materials (MMMs) containing PBI and palladium (Pd) nanoparticles, which have strong affinity towards H2 and thus exhibit extremely high H2/CO2 solubility selectivity. Pd nanoparticles with uniform diameters of 6 - 8 nm are prepared via hot-injection approaches, which show H2/CO2 solubility selectivity of 840, compared with < 0.1 for typical polymers. The effect of Pd loading (0 - 70 wt%) and temperature on the pure- and mixed-gas H2/CO2 separation properties is thoroughly evaluated. The loading of Pd nanoparticles dramatically increases H2 solubility and H2/CO2 solubility selectivity, resulting in a significant increase in H2 permeability and H2/CO2 selectivity at temperatures of 100 - 200 oC. For example, adding 70 wt% Pd in PBI increases H2 permeability from 25 to 70 Barrers, and H2/CO2 selectivity from 13 to 29 at 150 oC. Such performance is above the upper bound of the Robesonâs plot for H2/CO2 separation, demonstrating their potential for industrial H2/CO2 separation. This presentation will also examine morphology of the MMMs and describe a model to elucidate the relationship of the structure and H2 transport properties in these sorption enhanced MMMs.