PVDF Mixed Matrix Membranes Blended Ionic Liquid Intercalation Modified MXene And Its Anti-fouling Performance

Polyvinylidene fluoride（PVDF）membrane has been widely used in water treatment field.It is commonly used to prepare ultrafiltration membranes.However,the performance of the membrane,such as water flux and anti-fouling performance need to be enhanced.At present,the hydrophilic modification of membrane by physical blending is one of the most effective methods to improve membrane performance because of its simplicity and suitable for large-scale preparation.On the other hand,with the rapid development of nanotechnology,some new nano-materials,such as grapheme,MOF,COF,are considered to be ideal materials for the membrane modification with physical blending.MXene has two-dimensional layered structure and adjustable surface functional groups,which is also suitable for the modification of PVDF membrane.However,the multilayer structure and small layer spacing of MXene affect its dispersion in PVDF membrane and the improvement of membrane water flux.In this paper,MXene was impregnated with ionic liquid（IL）,and then MXene@IL/PVDF mixed matrix membranes was prepared by physical blending.The microstructures of MXene@IL/PVDF mixed matrix membranes were characterized by TEM,SEM,FT-IR and XRD analysis.The performance of the membranes was evaluated in the dead-end filtration.The results show that the interlayer spacing of MXene were increased through the intercalation of ionic liquid,and the permeability of water molecules between MXene lamellae were raised.Based on the amphiphilicity of ionic liquid,the dispersity of MXene in the mixed matrix membrane were promoted.MXene@IL/PVDF mixed matrix membrane had higher water flux and flux recovery rate,and the antifouling performance is significantly improved.The pure water flux of the MXene@IL/PVDF mixed matrix membrane was 125.97 L·m^-2·h^-1,and the flux recovery rate was 81.08%,which was about4.25 times and 1.76 times higher than that of PVDF membrane,respectively.In order to further improve the dispersion of MXene in MXene@IL/PVDF mixed matrix membrane,and enhance the performance of the membrane,MXene was modified by polyethyleneimine（PEI）using chemical grafting.Then the modified MXene（PEI-MXene）was intercalated with ionic liquid.Finally the PEI-MXene@IL/PVDF mixed matrix membranes were prepared by physical blending.The results shown that the hydrophilicity and layer spacing of PEI-MXene increased,and the compatibility between PEI-MXene and PVDF were improved.Compared with MXene@IL/PVDF mixed matrix membrane,The pure water flux of PEI-MXene@IL/PVDF mixed matrix membrane increased by 2.16 times,and reached272.36 L·m^-2·h^-1.After 4 cycles of test,water flux recovery rate of PEI-MXene@IL/PVDF mixed matrix membrane was more than 80%.