Application of polyvinylidene fluoride membrane with demulsification property in oil–water separation

Abstract

Membrane‐based treatment for demulsification remains a significant challenge due to membrane fouling. In this work, the demulsification and membrane separation technology were combined to design polyvinylidene fluoride (PVDF) membrane with demulsification function. The hyperbranched polyethyleneimine was prepared by the acyl chloride reaction and grafted on the PVDF membrane by dopamine. The effects of different amounts of hyperbranched polyethyleneimine on PVDF membrane were studied. The modified membrane was characterized by SEM, CA, FTIR, and XPS, and then the optimum preparation conditions were selected. The separation test shows that the modified membrane can be used to separate oil‐in‐water emulsions and the separation efficiency was more than 90%, meanwhile it showed good anti‐pollution performance owing to the water‐based protective layer on the membrane surface and the steric effect of the branches. In addition, the demulsification mechanism was analyzed and it was found that the surface tension was the key point for demulsification.

Durable superhydrophobic Fe3O4@C/PVDF/PU sponge for efficient separation of surfactant-stabilized organic solvent/water emulsions

“…3 Compared with immiscible oil/water mixtures, there are great challenges for the separation of surfactant-stabilized emulsions because the addition of surfactants enhances the kinetic and thermodynamic stabilities of the dispersed phase in the continuous phase. 4 Therefore, effective separation of surfactantstabilized emulsions as well as spilled oil and chemical organic solvents from polluted water has become an urgent task to protect water resource and reduce environmental pollution. 5,6 Conventional methods such as physical adsorption, 7-10 centrifugation, 11,12 solidifier usage, 13,14 in situ controlled combustion 15 and the addition of chemical dispersants 16 have been widely employed for oil/water separation.…”