A Novel Strategy to Prepare Anti-Fouling Composite Layer on Hydrophobic Membrane by Opposite Transmission Reaction

The surface modification method by depositing polymers can effectively improve anti-fouling performance of the hydrophobic membrane. However, the relatively thick composite layer formed by the conventional deposition reaction will cause a low permeate flux. Herein, an in-situ cross-linking reaction to prepare composite layer based on opposite transmission process is proposed for the first time. In this study, glutaraldehyde (GA) vapor reacts with polyvinyl alcohol (PVA) solution at the opening of the membrane pore channels to form composite layer. The results show that the composite layer formed by the opposite transmission reaction could more completely cover the large skin pores of hydrophobic membrane surface compared with that formed by the conventional deposition reaction. Therefore, the as-prepared composite membrane exhibited better anti-fouling performance. Moreover, the diffusion of GA vapor was limited after forming the integral composite layer. The thickness of the corresponding composite layer was merely 1.08 μm, which was 89.2% less than that of the composite layer formed by the conventional deposition reaction. Therefore, the permeate flux of the as-prepared composite membrane was much higher than that of the composite membrane prepared by the conventional deposition reaction. This study provides a novel strategy for preparing composite layer on hydrophobic membrane surface.