A novel conductive membrane with RGO/PVDF coated on carbon fiber cloth for fouling reduction with electric field in separating polyacrylamide

Directly applying an electric field on conductive membrane can effectively mitigate membrane fouling. Thus, a conductive reduced graphene oxide/polyvinylidene fluoride (RGO/PVDF) membrane was prepared by casting PVDF and graphene oxide (GO) solution over a selected carbon fiber cloth, then phase inversion and final heat treatment in hydroiodic acid (HI) solution. This method realized uniform and stable presence of RGO in PVDF membrane. Scanning electron microscopy (SEM) images showed addition of GO reduced the pore size of the composite membranes. The thermal HI treatment partially reduced graphene oxide to RGO, and made the membrane more conductive but less hydrophilic [as characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and contact angle (CA)]. From thermogravimetric analysis (TGA), it showed that the addition of GO and RGO improved the thermal stability of the membranes, when temperature was lower than 400 degrees C. The HI treatment increased the pore size and water flux of the RGO/PVDF membrane (being 71.6% higher than the GO/PVDF membrane). The RGO/PVDF membrane was used in separating polyacrylamide (PAM), a macromolecule pollutant in oil field waste water; when applying a 0.6 V/cm external electric field, its membrane fouling and flux decline was effectively slowed down, as shown in the fitting curves slopes using the classical cake filtration model (t/V-V). Being uniform and stable, the RGO/PVDF membrane had great potential for practical applications. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43597.