Oxidant-Induced Mussel-Inspired Modification on PVDF Membrane for Oil/Water Separation

  • Author / Creator
    Luo, Chongdan
  • In this study, an oxidant-induced mussel-inspired modification was implemented to prepare modified polyvinylidene fluoride (PVDF) membrane utilizing the deposition of polydopamine (PDA) coating, which was oxidized by sodium periodate under a slightly acidic condition (pH = 5.0). The surface chemistry and morphologies of the decorated membranes were investigated by FTIR, XPS, EDS, and FESEM. The wettability and permeating properties of the membranes were evaluated by contact angle measurements and filtration tests. The results indicated that the oxidant-assisted PDA coating exhibited outstanding performance in deposition efficiency, hydrophilicity and permeation enhancement as compared with the conventional PDA coating under an autoxidative polymerization process in air (pH = 8.5). This facile one-step methodology endowed the PVDF membrane with superhydrophilicity and underwater superoleophobicity owing to the hydrophilic functional groups and micro/nano-hierarchical structure formed on the membrane surface and pore walls according to the “Cassie-Baxter” state in the oil/water/solid system. After 2 h reaction, the modified PVDF membrane (pore size 0.45 μm) showed an ultrahigh water flux of 11934 ± 544 L m-2 h-1 under 0.038 MPa, and even reached 606 L m-2 h-1 only by gravity. This optimized membrane had an excellent capability to effectively separate oil/water mixtures and oil-in-water emulsions. In addition, the remarkable chemical and mechanical stabilities imply its great potential for the practical application in oil/water separation. Besides, the oxidant-induced PDA modified PVDF membrane (pore size 0.22 μm) showed the protein resistance against bovine serum albumin (BSA) via a rapid deposition time of 0.5 h. The wettability and surface zeta potential measurements indicated the improved hydrophilicity and the more negatively charged surface of the modified membrane, which led to the formation of the combined-water layer on the surface and the electrostatic repulsion to inhibit the adsorption or deposition of BSA, thus reducing the protein fouling. The dynamic protein filtration and static protein adsorption tests confirmed the promoted antifouling performance of the modified membrane at a neutral condition.

  • Subjects / Keywords
  • Graduation date
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.