Preparation of antifouling poly (ether ether ketone) hollow fiber membrane by ultraviolet grafting of polyethylene glycol

Abstract

Polyethylene glycols (PEG) with relative molecular weights of 2,000, 10,000, 20,000, and 50,000 were grafted onto the surface of Poly (ether ether ketone) (PEEK)hollow fiber membranes respectively by UV irradiation grafting methods. The surface morphology, pore structure, and filtration performance of the PEEK and PEEK-g-PEG membranes were investigated in detail. Moreover, the bovine serum protein(BSA)was used as a model foulant to characterize the antifouling performance of the membrane. The effects of grafting density and grafting chain length on membrane permeability and antifouling performance were explored. The results of surface morphology showed that after grafting polyethylene glycol, there was no significant decrease of the surface porosity. When the relative molecular weight of PEG is 2000, the normalized water flux of the PEEK-g-PEG2000 membrane is increased to 3.38, but the flux recovery rate is only 79.9 %; when the molecular weight of PEG is 50,000, the flux recovery rate of the PEEK-g-PEG50000 membrane is 99.2 %, but the normalized water flux decreased to 0.73. Therefore, the increase of hydrophilicity can improve the permeability of the membrane, but the long grafting chains easily plugs the membrane pores and reduces the permeability of the membrane. The research found that the grafting density and grafting chain length have different mechanisms of action to prevent the adsorption of foulants to the polymer matrix. The antifouling performance of PEEK membrane can be effectively improved by regulating the grafting density and grafting chain length.