Effect of different additives on the physicochemical properties and performance of NLDH/PVDF nanocomposite membrane

The main objective of this research was to introduce an appropriate additive for improving the properties and performance of the NLDH/PVDF nanocomposite ultrafiltration membrane. For this purpose, the effects of the different additives including hydrophilic polymers e.g. PVP (with molecular weight of 10,000 and 29,000) and PEG (with molecular weight of 1500 and 6000) and amphiphilic copolymer e.g. pluronic F-127 were investigated on the properties and performance of NLDH/PVDF nanocomposite membrane. The properties of the fabricated membranes were studied using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM) and water contact angle techniques. Moreover, the pure water flux, water flux of BSA solution and flux recovery ratio (FRR) were determined for fabricated membranes in order to investigate their permeability and antifouling property. The results indicated that there was an interaction between the NLDH nanolayers and additive molecules, and so the effect of both NLDH and additive should be simultaneously considered. The results obtained from analysis techniques indicated that the surface porosity, average surface pore size, surface hydrophilicity and cross-sectional morphology of the NLDH/PVDF nanocomposite membrane were efficiently improved by introducing 1 wt.% of PVP29000 to the matrix of the nanocomposite membrane. Furthermore, in the presence of PVP29000 as optimum additive, the NLDH/PVDF nanocomposite represented high pure water flux (702.2 L/m² h), high water flux of BSA solution (119.3 L/m² h) and good antifouling property (FRR of 73.41%).