Improving the hydrophilicity and fouling resistance of RO membranes by surface immobilization of PVP based on a metal-polyphenol precursor layer
Improving the hydrophilicity and fouling resistance of RO membranes by surface immobilization of PVP based on a metal-polyphenol precursor layer
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DOI：
10.1016/j.memsci.2015.08.044
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发表时间：
2015-12-15
影响因子：
9.5
通讯作者：
Wang, Shichang
中科院分区：
文献类型：
--
作者：
Wu, Junhui;Wang, Zhi;Wang, Shichang
为了提高聚酰胺反渗透(RO)膜的亲水性和抗污染性能，采用连续两步浸渍涂覆工艺对其进行了表面改性。在第一步中，通过单宁酸(TA)和Fe(III)离子的自组装，在膜表面沉积了一层超薄的金属-多酚前驱体，并加入了聚乙烯亚胺(PEI)作为共价交联剂。第二步，利用聚N-乙烯基吡咯烷酮(PVP)中的LAD：AM基团与前驱层中的酚羟基之间强烈的氢键作用，将一种常见的亲水性聚合物PVP固定在金属-多酚前驱体层上。X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和Zeta电位测试证实了前驱层和PVP的成功固定化。原子力显微镜(AM)测试表明，改性膜的表面更加光滑。此外，改性膜的水通量仅略有下降，对盐分的截留率几乎没有变化。更重要的是，静态接触角测量表明，EVE固定化后膜表面的亲水性显著提高(接触角从59.0+/-1.2度增加到14.5+/-2.4度)。以两种蛋白质(溶菌酶和牛血清白蛋白)和一种多糖(海藻酸钠)为模型污染剂，进行了三个“过滤-冲洗”周期的膜污染实验。污染实验结果表明，EVE的表面固定化明显提高了反渗透膜的抗污染能力。此外，在高水动力剪切条件下进行了15天的错流过滤试验，结果表明固定化EVE具有良好的稳定性。本工作为提高反渗透膜的抗污染性能提供了一种新的潜在策略。(C)2015爱思唯尔B.V.保留所有权利。
A commercial polyamide reverse osmosis (RO) membrane was surface modified in a sequential two-step dip coating process for improvement of the hydrophilicity and fouling resistance. In the first step, an ultrathin metal-polyphenol precursor layer was deposited onto the membrane surface via the self-assembly of tannic acid (TA) and Fe(III) ions, and polyethylenimine (PEI) was added as a covalent cross linker. In the second step, poly(N-vinylpyrrolidone) (PVP), a common hydrophilic polymer, was immobilized onto the metal-polyphenol precursor layer through the strong hydrogen bonding interactions between the lad:am groups in PVP and the phenolic hydroxyl groups in the precursor layer. X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscopy (TEM) and zeta potential measurements confirmed the successful immobilization of the precursor layer and PVP. Atomic force microscopy (AM) Lest indicated a smoother surface of the modified membrane. Furthermore, the water flux of the modified membrane was only slightly decreased and the salt rejection was almost unchanged. More importantly, static contact angle measurement showed that the membrane surface hydrophilicity was significantly improved after the EVE immobilization (contact angle horn 59.0 +/- 1.2 degrees to 14.5 +/- 2.4 degrees). Membrane fouling experiments were performed over three "filtration-rinsing" cycles using two proteins (lysozyme and bovine serum albumin) and one polysaccharide (sodium alginate) as model foulants. The results of the fouling experiments revealed that the fouling resistance of the reverse osmosis membrane was obviously improved by the surface immobilization of EVE. Besides, cross-flow Filtration test under high hydrodynamic shear condition for 15 days indicated the excellent stability of the immobilized EVE. This work provided a new potential strategy for improving the fouling resistance of RO membranes. (C) 2015 Elsevier B.V. All rights reserved.