Embedding Porous MXene into the Selective Layer of Pebax-Based Thin-Film Nanocomposite Membranes for Enhanced CO2 Removal Performance

Abstract

The robust two-dimensional MXene was synthesized from the MAX phase using the hydrofluoric acid etching method and mixed with a Pebax copolymer in a water–ethanol solvent mixture. Then, the resultant solvent mixture solution was coated onto the surface of the polysulfone (TFNc) membrane to compare its gas separation performance with that of the uncoated polysulfone membrane. The pristine PSF membrane was fabricated by utilizing the immersion precipitation phase inversion technique. The presence of MXene in the TFNc membrane was confirmed using FESEM analysis. The addition of MXene into the TFNc membrane was attributed to the changes in crystallinity, surface roughness, thermal stability, and pore volume, which were studied using XRD, AFM, TGA, and BET analyses, respectively. Subsequently, the gas separation studies of the TFNc were conducted, and it was observed that 0.5 wt % of the MXene-embedded TFNc membrane showed the maximum CO₂ permeance with a value of 23.822 GPU. It also displayed maximum CO₂/N₂ and CO₂/CH₄ selectivity since the MXene results in the creation of more tortuous pathways, as well as the hydroxyl group present on the MXene, which leads to the selective permeation of CO₂ molecules. Further, the long-term stability of the resultant TFNc membrane was studied for its application in industries.