Preparation of solvent-resistant composite polyimide nanofiltration membranes by vacuum-assisted interfacial polymerization combined with a magnetic field array of carbon nanotubes

Solvent-resistant nanofiltration (SRNF) membranes have excellent applications in wastewater treatment, such as organic solvent recovery and water purification. However, the high performance with high solvent permeability passing through the membrane is still a big challenge. We prepared polyimide (PI) SRNF membranes with highly efficient oriented nanochannels via vacuum-assisted interfacial polymerization and magnetic field arraying magnetized functionalized multi-walled carbon nanotubes (MWCNTs). This prepared composite membrane got a molecular weight cutoff of around 600-800 Da, significantly improving the permeability but no change in rejection performance. When MWCNTs were magnetically oriented, the permeability raised from 7.8 to 15.9 L/m-2 h-1 bar-1, which was 103% higher than that of the non-arrayed composited membrane. The stability test illustrated that the permeability rose slightly, but the rejection rate of the CaSO4 solution was kept at 92-94% after being immersed in polar organic solvents for 48 h. This work aimed to design an innovative method for preparing a high-performance SRNF membrane that introduced an arranged nanochannel.

Automated summary

The research team prepared polyimide SRNF membranes with highly efficient oriented nanochannels using vacuum-assisted interfacial polymerization and magnetic field arraying magnetized functionalized multi-walled carbon nanotubes (MWCNTs). The prepared composite membrane showed improved permeability without compromising rejection performance.