High-Performance Composite Membrane with Enriched CO₂-philic Groups and Improved Adhesion at the Interface

Abstract

A novel strategy to design a high-performance composite membrane for CO2 capture via coating a thin layer of water-swellable polymers (WSPs) onto a porous support with enriched CO2-philic groups is demonstrated in this study. First, by employing a versatile platform technique combining non-solvent-induced phase separation and surface segregation, porous support membranes with abundant CO2-philic ethylene oxide (EO) groups at the surface are successfully prepared. Second, a thin selective layer composed of Pebax MH 1657 is deposited onto the support membranes via dip coating. Because of the water-swellable characteristic of Pebax and the enriched EO groups at the interface, the composite membranes exhibit high CO2 permeance above 1000 GPU with CO2/N2 selectivity above 40 at a humidified state (25 °C and 3 bar). By tuning the content of the PEO segment at the interface, the composite membranes can show either high CO2 permeance up to 2420 GPU with moderate selectivity of 46.0 or high selectivity up to 109.6 with fairly good CO2 permeance of 1275 GPU. Moreover, enrichment of the PEO segment at the interface significantly improves interfacial adhesion, as revealed by the T-peel test and positron annihilation spectroscopy measurement. In this way, the feasibility of designing WSP-based composite membranes by enriching CO2-philic groups at the interface is validated. We hope our findings may pave a generic way to fabricate high-performance composite membranes for CO2 capture using cost-effective materials and facile methods.

Hollow ZIF-8 nanoparticles improve the permeability of mixed matrix membranes for CO2/CH4 gas separation

“…H_ZIF-8 was homogeneously mixed with PVC-g-POEM polymer matrix without any apparent interfacial voids or particle aggregation, regardless of H_ZIF-8 content. We expected the good adhesion between H_ZIF-8 and PVC-g-POEM to provide effective gas permeation and separation properties, because compatibility between the filler and polymer matrix is of pivotal importance in MMMs [12,[34][35][36][37][38]. The maximum loading amount of H_ZIF-8 for robust free-standing MMMs was 30 wt%, above which the MMMs became too brittle to be installed in the time-lag machine, which operates under high vacuum conditions.…”

Preparation and characterization of a polyethersulfone/polyaniline nanocomposite membrane for ultrafiltration and as a substrate for a gas separation membrane

“…It was reported that the polymer chains within the pores displayed lower mobility and were described as "chain rigidification", which would cause a decrease of gas permeance and an increase of selectivity. 25 In order to investigate the difference in the spread and penetration of coating solution on PES and PES/PANI substrates, the dynamic contact angle of coating solution on the substrats was recorded using 2.0 wt% PVAm coating solution as the dispense liquid. As shown in Fig.…”

“…While recently more and more researchers are realizing the importance of porous membrane supports on the performance of composite membrane and attempt to figure out the suitable properties of substrates for fabricating composite membrane. [19][20][21][22][23][24][25][26] In the published studies, the surface properties of the substrates were mainly altered by varying the polymer concentration 21 and blending polyvinylpyrrolidone (PVP) or poly (ethylene glycol) (PEG) 23 in the casting solution. It was reported that the porous support membrane could exert an effect on the selective layer structure besides providing the mechanical support for fabricating composite membrane.…”

“…24 During the fabrication of GS composite membrane by coating, the pore size or surface functional groups of the substrate could influence the interface structure between the selective and support layers. 25,26 As one of the most promising conducting polymers, polyaniline (PANI) has received great attention as a membrane material or blending modifier during the preparation of UF and GS membranes. [27][28][29][30][31][32][33][34] PANI nanomaterials could be incorporated into the casting solution or coating solution to modify the porous membrane or the selective layer of the composite membrane.…”

Enhanced CO2 separation properties by incorporating poly(ethylene glycol)-containing polymeric submicrospheres into polyimide membrane

“…Low molecular weight poly(ethylene glycol) (PEG) with abundant polar ether groups could produce dipole-quadrupole interactions with CO 2 and has been recognized as an effective polymer to achieve high CO 2 permeability and CO 2 /other gas selectivity [18,21,22]. Numerous efforts have been devoted to explore PEGcontaining blend membranes [23], copolymer membranes [24] and hybrid membranes [25,26] for efficient CO 2 separation.…”