Cellulose acetate blending and cellulose nanocrystal doping improve the diafiltration and antifouling properties of polyvinylidene fluoride membranes

In this paper, cellulose acetate (CA) and cellulose nanocrystal (CNC) modified polyvinylidene fluoride (PVDF) membranes were prepared by solution blending and non-solvent induced phase separation methods to improve the hydrophilicity and diafiltration capacity of the membranes. The changes in membrane performance before and after modification were systematically studied through simulated dialysis experiments, antifouling performance tests and biocompatibility analysis. The results show that CA blending and CNC doping will change the morphology and structure of the PVDF membrane, improve its hydrophilicity and permeability, and make it show better filtration capacity and antifouling performance. The modified PVDF membrane has higher clearance and diafiltration efficiency for small molecular solutes urea and creatinine, especially for the middle molecular solute lysozyme, while retaining most of the protein molecules, with a flux recovery rate of more than 95%. The modified PVDF membrane also has good biocompatibility. Bio-based CA and CNCs play an important role in improving the antifouling and diafiltration capacity of PVDF membranes.