The role of geometrically different carbon-based fillers on the formation and gas separation performance of nanocomposite membranes

Abstract

Carbon nanotube (CNT) incorporated thin film nanocomposite (TFN) is a promising membrane for gas separation. However, agglomeration of CNT tends to occur due to its high aspect ratio and strong Van de Waals force. This study aims to improve the dispersion of CNT in TFN membrane through the addition of amphiphilic graphene oxide (GO) nanosheet. Interfacial polymerization (IP) technique was employed for the synthesis of thin selective layer atop a porous polysulfone (PSF) support. Amino acid functionalization was performed on CNT and GO and its impact on IP was evaluated. It was observed that the nanomaterials properties such as dispersibility, absorptivity and hydrophilicity could affect the reactivity of IP which in turn altered the characteristics of selective layer. Separation results showed that co-incorporation of amino acid modified CNT and GO improved the permeability and selectivity of TFNs by 30% and 60%, respectively. The resulted TFN was also more reproducible and stable under different applied pressures and exposure to air. The outcome of this study suggested that synergetic incorporation of the two geometrically different carbon-based nanomaterial could provide an additional degree of freedom to control the selective film formation as compared to single-filler incorporation.