A COF-coated polyamide membrane fabricated by vapor-assisted conversion for water-in-oil emulsion separation

Abstract

The separation of water-in-oil emulsion is of great significance, but some difficulties remain in the present study. Herein, a COF-coated polyamide membrane (PA@COF) was prepared by vapor-assisted conversion at room temperature. The TFB-BD(Me)₂ COF, with blocks of 1,3,5-benzenetricarboxaldehyde (TFB) and 3,3′-dimethyl-[1,1′-biphenyl]-4,4′-diamine (BD(Me)₂), is highly hydrophobic, making the COF-coated membrane display hydrophobicity with a contact angle of around 100°. The PA@COF membrane showed good separation ability for filtering various water-in-oil emulsions. The separation efficiency for different water-in-oil emulsions can be as high as 99.7% and the flux could reach 4583 L m⁻² h⁻¹. Overall, the vapor-assisted conversion exhibits good potential for fabricating functional membranes for applications such as oil/water separation.