Highly selective hollow fiber membranes for carbon capture via in-situ layer-by-layer surface functionalization
Multilayer films of poly(ethylene oxide) (PEO) and poly(methyl acrylic acid) (PMAA) deposited on a Torlon© poly(amide imide) (PAI) hollow fiber substrate using layer-by-layer (LbL) method yield highly CO2-selective membranes. These all-polymer membranes were deposited in-situ on low-cost, high permeability, and low selectivity Torlon© hollow fibers for post-combustion carbon capture. Surface functionalization of hollow fibers using poly(ethylene imine) (PEI) in isopropanol increased hydrophilicity, aiding LbL deposition. Coatings of [PEO2/PMAA2] polymeric pair were successfully deposited on both untreated hollow fiber (10, 15, and 20 bilayers) and PEI-functionalized hollow fiber substrates (2, 5, and 10 bilayers) achieving one of the highest reported selectivity for CO2:N2 (240:1) at 1018 Barrer CO2 permeability (101 GPU permeance); exceeding the 2008 Robeson upper bound for homogenous polymer films. These results suggest membranes deposited via in situ LbL methodology on industrially applicable hollow fibers pave a way for carbon capture from flue gases at power plants.
N. K. Mishra, N. Patil, S. Yi, D. Hopkinson, J. C. Grunlan, B. A. Wilhite, J. Membr. Sci., 2021, 633, 119381.