Novel antibifouling nanofiltration polyethersulfone membrane fabricated from embedding TiO ₂ coated multiwalled carbon nanotubes

Multiwalled carbon nanotubes (MWCNTs) coated by anatase titanium dioxide (TiO ₂) nanoparticles were synthesized via the precipitation of TiCl ₄ precursor on the acid oxidized MWCNTs and used in preparation of nanocomposite polyethersulfone (PES) membranes. In this work, the effect of embedding TiO ₂ coated MWCNTs in PES matrix on membrane morphology, properties and antibiofouling was presented and the obtained results were compared with the prepared oxidized MWCNTs and TiO ₂ blended PES membranes. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses showed that the formed TiO ₂ on the surface of MWCNTs had anatase nanostructure with size in the range of 10-20 nm. The scanning electron microscopy (SEM) images displayed a finger-like and porous structure for all NF membranes and showed that agglomeration of TiO ₂ coated MWCNTs is very low. Contact angle measurements indicated that coating of TiO ₂ nanoparticles on the surface of oxidized MWCNTs improved the hydrophilicity of the obtained membranes. The pure water flux of the blend membranes increased with the content of TiO ₂ coated MWCNTs. Fouling resistances of membranes evaluated by whey solution filtration revealed that 0.1 wt.% TiO ₂ coated MWCNTs membrane had the best antibiofouling properties due to its lowest surface roughness and synergistic photocatalytic activity induced by incorporated nanoparticles.