Synthesis of PVDF/MWCNT nanocomplex microfiltration membrane via atom transfer radical addition (ATRA) with enhanced fouling performance

Abstract Polyvinylidene fluoride (PVDF) membranes were combined with multiwall carbon nanotubes (MWCNTs) through atomic transfer radical addition (ATRA) to improve flux and fouling resistance. The novel PVDF membranes were achieved by introducing amine-modified MWCNTs including ethylamine, octylamine, and octadecylamine, to improve dispersion and hydrophilicity. ATRA synthesis was conducted by adding a ligand and a catalyst when preparing the PVDF solution. PVDF-modified MWCNT nanocomplex membranes were prepared by the non-solvent induced phase separation process (NIPS), and MWCNTs were chemically combined with the PVDF. The water flux of the AT-E0.01 membrane (2137 LMH) increased by more than 155.3% in comparison with the PVDF membrane (837 LMH). The high protein rejection greater 98% was retained for the AT-E0.01 membrane, and BSA adsorption showed a lower value than the pristine PVDF membrane. This was attributed to formation of a hydration layer on the membrane through increased binding and capture of water molecules by hydrogen bonds and the hydrophilic Cu[DNDP]3MWCNT-EA complex in PVDF polymer. The flux recovery ratio of AT-E0.01 was 92.7% after three cycles of fouling performance, which indicates excellent fouling resistance. As a result, the AT-E0.01 membrane had excellent water flux and fouling resistance due to its high hydration capacity, hydrophilicity, smooth surface, and negatively surface charge.