In-situ growth of double-layered polyaniline composite membrane for organic solvent nanofiltration

The trade-off between permeability and rejection limits the widespread application of organic solvent nanofiltration (OSN) membrane. As a promising membrane materials, polyaniline (PANI) has drawn increasing attention owing to its easy synthesis and excellent chemical stability. Nowadays, the reported PANI-based OSN membranes were fabricated by phase inversion process together with chemical crosslinking treatment. In this work, a novel double-layered polyaniline (PANI) composite OSN membrane was firstly developed through in-situ polymerization of aniline onto hydrolyzed polyacrylonitrile (HPAN) porous substrate. The separation performances of PANI/HPAN composite membrane were optimized by varying aniline concentration, polymerization time and oxidant:aniline ratio. The double-layered PANI/HPAN composite membrane prepared with 0.2 M aniline, 1 h polymerization and 1:4 oxidant:aniline ratio displayed ethanol permeance of 14.9 L∙m−2∙h−1∙bar−1 and rose bengal rejection of 98.1%. The membrane performance with the solvents including methanol, isopropanol, 1-butanol, acetone, n-hexane, and toluene were also tested, showing a molecular weight cut-off (MWCO) of 500 ∼ 600 g∙mol−1. In addition, the double-layered PANI/HPAN composite membrane maintained excellent and stable performance under strong acid soaking, ultrasonic vibration and continuous filtration