(361h) Laser Induced Graphene on Polysulfone Membrane for H2/CO2 Gas Separation

There has been a growing interest in polymeric membranes for gas separation due to their low cost, low energy usage, and lack of moving parts. Dense polymeric membranes have an intrinsic trade-off between selectivity and permeability based on the kinetic diameter of the gases involved. Molecular sieving materials like graphene-based nanomaterials, MXenes, zeolites, and carbon nanotubes. shown promising applications in gas separation membranes. Mixed matrix membranes with improved selectivity over polymeric membranes have been developed by adding nanomaterials as fillers in polymer matrix. However, the membrane fabrication is limited by dispersion of fillers because of their incompatibility with polymer matrix and the membrane performance is compromised due to unselective voids. ^[1] Laser induced graphene (LIG) can be photothermally formed on surface of polymeric substrates; this method is fast and scalable and has been applied for ultrafiltration applications in polysulfone, polyethersulfone, and polyphenylsulfone.^[2]

Here, we report that LIG on surface of polysulfone substrates can enhance the H₂/CO₂ perm-selectivity of the control polysulfone film. A new class of heterogeneous mixed matrix membranes is developed by forming graphene on surface of polymer and combining molecular sieving mechanism with solution-diffusion mechanism of baseline polymers. In a proof-of-concept experiment, we have used LIG on 100 micrometers thick polysulfone substrate for separation of light gas pair H₂/CO₂ at room temperature and 1 atm pressure. Preliminary measurements indicate that this combination is a high perm-selectivity membrane with a selectivity of 51 and permeance of 707 GPU (1 GPU = 3.35 x 10^-10 mol/m²/Pa) as compared to neat polysulfone with selectivity of 2 and permeance of 1 GPU. X-Ray Diffraction analysis, thermogravimetric data, optical and scanning electron microscopy were utilized to study the final material; these characterizations confirmed graphene formation on the substrate.

References:

[1] M. Etxeberria-Benavides, O. David, T. Johnson, M. M. Łozińska, A. Orsi, P. A. Wright, S. Mastel, R. Hillenbrand, F. Kapteijn, J. Gascon, Journal of Membrane Science 2018, 550, 198.

[2] S. P. Singh, Y. Li, J. Zhang, J. M. Tour, C. J. Arnusch, ACS Nano 2018, 12, 289.