The effect of functional carbon nanotubes on the permeability of ultrafiltration nanocomposite PVDF membranes

Flux and antifouling performance of poly(vinylidnene fluoride) (PVDF) (15wt%.) nanocomposite ultrafiltration membrane with different functional carbon nanotubes (–COOH, –OH, –NH2) are considered. Membranes are prepared with phase‐inversion method using n‐methylpyrrolidone as solvent. This is the first time that hydrophilicity of different nanocomposite membranes are changing gradually, as performance of nanocomposite membrane are considered. Gradually changing of hydrophilicity explains behavior and performance of nanocomposite membrane. Scanning electron microscopy analysis of PVDF membrane with different functional multiwall carbon nanotube (FMWCNT) showed that all prepared membranes are asymmetric structure with a compact top layer and a bottom layer with large pore channels. All modified nanocomposite membranes show better hydrophilicity surface in compared with pristine PVDF membrane (87°). Results of pure water flux are approved by the result of contact angle and porosity. Measurement flux membranes with optimized percent FMWCNT is increased more than twofold compared to pristine membrane (146 L·m−2·hr−1). Atomic force microscopic also revealed that modified membranes have smaller roughness in compared with neat membrane (Sa = 270 nm). Flux recovery ratio analysis for all membranes is increased more than pure membrane (39%) because of better hydrophobicity and decrease of roughness. This subject is shown that FMWCNTs have no detrimental effect on mechanical resistance in modified membranes.