(646a) Nanoengineered Solvent-Resistant Membranes from Biophenols and Graphene

Separating molecules dissolved in organic solvents is particularly important in pharmaceutical processing, where separations can account for as much as 70% of the total manufacturing cost. Organic solvent nanofiltration (OSN) membranes have the potential to achieve lower energy consumption than conventional separation processes. Despite the increasing interest in the OSN field, it is still an ongoing endeavor to improve separation performance and long-term stability of membranes. Our research provides solutions by designing new membrane nanocomposites for advanced separations in organic media:

• Polybenzimidazole (PBI) was functionalized with hydroxyl groups, followed by covalent grafting of graphene oxide on the polymer matrix, which tripled the solvent permeance (up to 45 L m^−2 h^−1 bar^−1 for acetone) while maintaining high solute rejection with molecular weight cutoff (MWCO) down to 140 g mol^−1.[1]
• Polymer of intrinsic microporosity (PIM-1) was blended into a PBI matrix, followed by the reduction of nitrile to amine, and ion-stabilization. The modification simultaneously increased solvent permeance and enabled fine-tuning of the MWCO of the membranes between 190 and 650 g mol^−1 in various media including polar aprotic solvents.[2]
• A novel membrane fabrication method that realizes the in situ polymerization of dopamine during PBI membrane formation was developed. The formation of interpenetrating polymer networks (IPN) endows the membranes with resistance towards polar aprotic solvents. The obtained membranes have MWCO values in the range of 190−850 g mol^−1 and permeances in the range of 2−19 L m^−2 h^−1 bar^−1.[3]
• A matrix of membranes comprising of broad combination of biophenol coatings and polymer supports was explored. Nanoengineering of the polymer membrane surface resulted in tunable membrane performance through systematic, versatile, reproducible and easily scalable biophenol coatings.[4]

References

[1] F. Fei, L. Cseri, G. Szekely, C.F. Blanford, Robust Covalently Cross-linked Polybenzimidazole/Graphene Oxide Membranes for High-Flux Organic Solvent Nanofiltration, ACS Applied Materials & Interfaces, 2018, 10, 16140–16147.

[2] G. Ignacz, F. Fei, G. Szekely, Ion-Stabilized Membranes for Demanding Environments Fabricated from Polybenzimidazole and its Blends with Polymers of Intrinsic Microporosity, ACS Applied Nano Materials, 2018, 1, 6349–6356.

[3] D. Zhao, J.F. Kim, G. Ignacz, P. Pogany, Y.M. Lee, G. Szekely. Bio-Inspired Robust Membranes Nanoengineered from Interpenetrating Polymer Networks of Polybenzimidazole/Polydopamine, ACS Nano, 2019, 13, 125–133.

[4] F. Fei, H.A. Le Phuong, C.F. Blanford, G. Szekely, Tailoring the Performance of Organic Solvent Nanofiltration Membranes with Biophenol Coatings, ACS Applied Polymer Materials, just accepted, DOI: 10.1021/acsapm.8b00161