In this study, we developed a hierarchical thin-film nanofibrous composite (TFNC) membrane with electrospun mat as substrate and hydrophilic nanocellulose as the antifouling barrier layer. We found that, due to the super-hydrophilic nature of the nanocellulose, the contact angle of the barrier layer ( 20 − 28 ° ) decreased rapidly with time and reached nearly zero after a few seconds, whereby the membrane flux were remarkably higher ( 52 L . m − 2 . h − 1 ) than conventional polymeric membranes ( 4 − 14 L . m − 2 . h − 1 ) at a very low transmembrane pressure of 0.5 psi. In addition, the membrane surface was considerably more negatively-charged due to the high concentration of carboxylate groups, resulting in higher repulsive electrostatic forces between the barrier layer and the model foulant. As a result, the nanocellulose-based hierarchical membranes exhibited a lower fouling tendency ( 10 % ) and a higher degree of protein rejection ratio compared with the conventional membranes (fouling tendency > 30 % ). The effect of the nanocellulose layer thickness on the membrane fouling was also examined and it was demonstrated that the nanocellulose barrier layer thickness had a significant effect on the membrane fouling. The higher flux, lower fouling, and good rejection properties of this membrane system suggest nanocellulose is a promising barrier material for filtration membranes for water purification and other separation processes.
