Journal of Membrane Science, Vol.577, 91-103, 2019
Influence of non-solvent chemistry on polybenzimidazole hollow fiber membrane preparation
Polybenzimidazole membrane materials have attractive H-2/CO2 separation characteristics and high thermochemical stability for elevated temperature synthesis (syn) gas separations. The development of PBI membranes with a thin defect-free selective layer and porous support morphology is vital to achieving industrially attractive separation performance. This work is focused on developing a fundamental understanding of the liquid-liquid demixing-based phase inversion process for asymmetric PBI hollow fiber membrane (HFM) formation. The development of industrially attractive HFMs is a challenging process due to the complex interplay between phase equilibria, phase inversion kinetics, and interfacial mass transfer that exist during the liquid-liquid demixing process. Numerous parameters including the dope, bore, and outer coagulant chemistries and compositions significantly influence the HFM morphologies produced. Here, a systematic study is conducted to investigate the phase inversion process parameters including the roles of the non-solvent solubility and diffusivity parameters with respect to the solvent and PBI on the phase inversion process. Furthermore, the influence of dope, bore and coagulant chemistries and compositions on PBI HFM morphology are investigated. The fabricated PBI HFMs are evaluated for their ideal H-2 and CO2 permeance and H-2/CO2 selectivity at 250 degrees C to benchmark their separation performance.
Keywords:Polybenzimidazole;Hollow fiber membrane fabrication;Non-solvent selection;Selective layer optimization;Phase inversion;Syngas separation;Carbon capture;IGCC