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

In this work, polyethersulfone (PES)/polyaniline (PANI) nanocomposite membranes were fabricated by an immersion precipitation process through incorporation of uniform and well-dispersed PANI nanorods. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used to identify the nanoparticle size and dispersion. The influence of incorporated PANI nanorods on membrane structure was investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). The properties of the nanocomposite membrane were evaluated by water contact angle, cross-flow ultrafiltration (UF) and antifouling measurements. The results indicated that the surface pore structure and hydrophilicity of PES membrane were improved by the incorporation of PANI nanorods. The PES/PANI nanocomposite membrane showed higher flux and better antifouling properties compared to the pure PES membrane without sacrificing the separation performance of BSA protein. Meanwhile, PES/PANI nanocomposite membrane was also used as the substrate to prepare a gas separation composite membrane by coating polyvinylamine (PVAm) aqueous solution on the surface. The gas permeation results showed that the PVAm/PES/PANI composite membrane exhibited higher gas permselectivity for CO2-N-2 separation than the PVAm/PES composite membrane, which may result from the improved surface porosity of PES/PANI substrate and the improved interface adhesion between the selective layer and the substrate.