Superior fouling resistant PVDF membrane with enhanced filtration performance fabricated by combined blending and the self-polymerization approach of dopamine

Abstract

This work presents a new and simple modification approach to fabricate a Polyvinylidene Fluoride membrane with superior permeation, separation, and antifouling performance. Dopamine was introduced by blending into the membrane casting solution and the membrane was prepared using a classic non-solvent induced phase separation technique. The prepared flat-sheet membrane was then dipped into a Tris-HCl buffer solution with a pH of 8.5 to trigger the polymerization of dopamine into polydopamine. The effects of the modification on the membrane characteristics were analyzed in terms of a change in the chemical components, hydrophilicity, surface porosity, and mechanical strength. In addition, the permeation, separation, and fouling resistant performance were studied by means of a filtration experiment using deionized water and humic acid solution as feeds. The results revealed that the addition of dopamine successfully increased the porosity by 300%, hydrophilicity by 180%, and water flux performance by 600% compared to the original membrane. Polymerization of dopamine into the polydopamine layer recovered the loss of rejection due to pore enlargement by dopamine blending from 91 to 93%. In addition, the blended and polymerized membrane successfully recovered up to 92% of pure water flux after backwash, which indicates the superior antifouling performance. It can be concluded that this new technique can be a potential approach to produce membranes for the water treatment process with overall excellent performance.