Improving multifunctional properties of the polyvinylidene fluoride (PVDF) membrane with crosslinked dialdehyde-starch (DAS) and polyethyleneimine (PEI) coating.

Dialdehyde-soluble starch (DAS) and polyethyleneimine (PEI) were used to coat the polyvinylidene fluoride (PVDF) membrane for improving its antifouling and multifunctional properties through a combination of dip-coating and spray-coating techniques. The resulting membrane demonstrated excellent hydrophilicity and underwater oleophobicity due to hydrophilic DAS and PEI on its surface. The membrane achieved an impressive oil removal rate of 99.8 % and a flux 1420.8 ± 26.5 L·m-2·h-1 when it was used for oil-water emulsion separation. The hydration layer formed by the DAS and PEI greatly enhanced the membrane antifouling property, and its flux recovery rate was up to 96.6 % in BSA filtration experiments. The positive charge PEI and the negative charge DAS contributed to high separation efficiency of 99.1 % for the anion dye MO with the membrane D10P20, and high separation efficiency of 88.3 % for the cation dye RhB with the membrane P5D20. In addition, the coating layer was stable due to the cross-linked DAS and PEI. This research contributes greatly to the preparation of antifouling and multifunctional membrane using environmentally friendly material including polysaccharide derivatives and water soluble polymer.