Oriented structure design and evaluation of Fe3O4/o-MWCNTs/PVC composite membrane assisted by magnetic field

A composite polyvinyl chloride (PVC) separation membrane blending with magnetic nanoparticles (NPs) was successfully prepared via the non-solvent induced phase separation (NIPS) method assisted by magnetic field. The magnetic Fe3O4/ oxidized multi-walled carbon nanotubes (o-MWCNTs) composite NPs with excellent hydrophilicity and magnetization were synthesized by chemical co-precipitation method. Then the Fe3O4/o-MWCNTs/PVC composite membrane included the Fe3O4/o-MWCNTs/PVC functional layer and PVC support layer was fabricated under the induction of the magnetic field. The effects of the addition of magnetic Fe3O4/o-MWCNTs NPs and its directional migration under magnetic field on the structure and performance of prepared Fe3O4/o-MWCNTs/PVC composite membrane were investigated. The results showed that the addition of hydrophilic magnetic Fe3O4/o-MWCNTs NPs and its directional migration to the membrane surface under the action of magnetic field promoted the process of double diffusion and microphase separation processes, which simultaneously increased the membrane porosity, hydrophilicity, pure water flux and BSA rejection ratio. The prepared Fe3O4/o-MWCNTs/PVC composite membrane exhibited higher pure water flux (400 L·m−2·h−1) and outstanding BSA rejection ratio (89%), which was increased by 60 and 117% compared with the PVC pristine membrane, respectively.