State Key Laboratory of Separation Membranes and Membrane Processes, School of Textiles, Tianjin Polytechnic University , Tianjin 300387, China.
ACS Appl Mater Interfaces. 2016 Jul 20;8(28):18418-29. doi: 10.1021/acsami.6b04083. Epub 2016 Jul 11.
Hybrid membranes blended with nanomaterials such as graphene oxide (GO) have great opportunities in water applications due to their multiple functionalities, but they suffer from low modification efficiency of nanomaterials due to the fact that plenty of the nanomaterials are embedded within the polymer matrix during the blending process. Herein, a novel Fe3O4/GO-poly(vinylidene fluoride) (Fe3O4/GO-PVDF) hybrid ultrafiltration membrane was developed via the combination of magnetic field induced casting and a phase inversion technique, during which the Fe3O4/GO nanocomposites could migrate toward the membrane top surface due to magnetic attraction and thereby render the surface highly hydrophilic with robust resistance to fouling. The blended Fe3O4/GO nanocomposites migrated to the membrane surface with the magnetic field induced casting, as verified by X-ray photoelectron spectroscopy, elemental analysis, and energy dispersive X-ray spectroscopy. As a result, the novel membranes exhibited significantly improved hydrophilicity (with a contact angle of 55.0°) and water flux (up to 595.39 L m(-2) h(-1)), which were improved by 26% and 206%, 12% and 49%, 25% and 154%, and 11% and 33% compared with those of pristine PVDF membranes and PVDF hybrid membranes blended with GO, Fe3O4, and Fe3O4/GO without the assistance of magnetic field during membrane casting, respectively. Besides, the novel membranes showed high rejection of bovine serum albumin (>92%) and high flux recovery ratio (up to 86.4%). Therefore, this study presents a novel strategy for developing high-performance hybrid membranes via manipulating the migration of nanomaterials to the membrane surface rather than embedding them in the membrane matrix.
基于多种功能，混合了氧化石墨烯（GO）等纳米材料的混合膜在水应用中具有巨大的发展潜力，但由于在混合过程中大量纳米材料嵌入聚合物基质中，纳米材料的改性效率较低。在此，通过磁场诱导铸造和相转化技术的结合，开发了一种新型的 Fe3O4/GO-聚偏二氟乙烯（Fe3O4/GO-PVDF）混合超滤膜，在此过程中，由于磁性吸引，Fe3O4/GO 纳米复合材料可以迁移到膜的表面，从而使表面具有极强的亲水性和抗污染能力。通过 X 射线光电子能谱、元素分析和能量色散 X 射线光谱验证了混合的 Fe3O4/GO 纳米复合材料在磁场诱导下向膜表面迁移。结果，新型膜表现出显著提高的亲水性（接触角为 55.0°）和水通量（高达 595.39 L m(-2) h(-1)），与原始 PVDF 膜相比，分别提高了 26%和 206%、12%和 49%、25%和 154%和 11%和 33%；与未施加磁场时仅添加 GO、Fe3O4 和 Fe3O4/GO 的 PVDF 混合膜相比，分别提高了 26%和 206%、12%和 49%、25%和 154%和 11%和 33%。此外，新型膜对牛血清白蛋白的截留率大于 92%，通量恢复率高达 86.4%。因此，本研究提出了一种通过控制纳米材料向膜表面迁移而不是将其嵌入膜基质中从而开发高性能混合膜的新策略。
