Nanofibrous ultrafiltration membranes containing cross-linked poly(ethylene glycol) and cellulose nanofiber composite barrier layer

Nanofibrous ultrafiltration membranes based on the thin-film nanofibrous composite (TFNC) format with a nanocomposite barrier layer made of cross-linked poly(ethylene glycol) (PEG) matrix and ultra-fine cellulose nanofibers (CN, ∼5 nm in diameter) were demonstrated. Physical properties, including pore size, chemical composition, morphology, hydrophilicity and surface roughness of these membranes, were characterized by filtration test, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), water contact angle measurements and atomic force microscopy (AFM). It was found the cross-linked PEG/CN barrier layer was highly hydrophilic and had excellent anti-fouling properties, which were confirmed by short-term and long-term fouling tests using bovine serum albumin (BSA) solution (1 g/L). In addition, the membranes exhibited better anti-fouling properties and recovery ability than comparable commercial membranes (e.g., Pall Life Sciences omega membranes and Koch HFK 328 membranes). For example, the flux of the composite layer was about twice as high as that of commercial membranes during the long-term testing, while the rejection was maintained above 90%.