Preparation and characterization of carbon molecular sieve membranes for gas separation—the effect of incorporated multi-wall carbon nanotubes

• Published in: Desalination 2009-05, Vol.240 (1), p.40-45
• Main Authors: Tseng, Hui-Hsing, Kumar, Itta Arun, Weng, Tzu-Hsiang, Lu, Chi-Yuan, Wey, Ming-Yen
• Format: Article
• Language: English
• Subjects: Applied sciences; Carbon membranes; Carbon nanotube; Chemical engineering; Exact sciences and technology; Gas separation; Membrane separation (reverse osmosis, dialysis...); Nanocomposite; Pollution; Polyimide
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2008.01.048

A new class of multi-wall carbon nanotubes (MWCNTs)/carbon nanocomposite thin films was successfully prepared by incorporating (MWCNTs) into polyimide (PI) precursor solution. The carbon films were obtained in only one coating step by spin-coating technique on a macroporous alumina substrate and were pyrolyzed at 773 K. The structure and single gas permeation properties of PI-based carbon membranes incorporated with or without MWCNTs were investigated. From the FE-SEM images, the pure carbon membranes have a thin dense permselective layer with few closed pores while the permselective layer of the MWCNTs/carbon nanocomposite thin films are porous due to the structure of nanotubes. The MWCNTs/carbon nanocomposite thin films exhibited that the ideal carbon dioxide flux was 866.6 Barrer (1 Barrer = 1×10 −10 cm 3 (STP) cm cm −2 s −1 cm Hg −1) and the separation factor of CO 2/N 2 was 4.1 at room temperature and 1 atm, which was 2–4 times of magnitude higher than that of pure carbon membrane prepared by the same procedures and conditions.