Background

Developing a novel loose NF membrane with zero NaCl rejection as well as effective anti-adhesive and anti-bacterial properties is significant for recycling and purification applications in many industries.

Materials and method

A novel anti-biofouling loose nanofiltration (NF) membrane was fabricated by crosslinking a graft copolymer chitosan-g-poly(sulfobetaine methacrylate) (CS-g-PSBMA) as selective layer of a thin film composite (TFC) membrane for dye/salt separation. Specifically, CS-g-PSBMA was synthesized using cerium (IV) ion as the oxidant to initiate the graft polymerization of SBMA from CS. The PSF membrane was pre-wetted with hyperbranched polyethylenimine solution, then the loose NF membrane was fabricated by crosslinking CS-g-PSBMA with glutaraldehyde on the polysulfone (PSf) ultrafiltration membrane as the support layer.

Results and discussion

Upon optimization, the membranes show minimal rejection rates to NaCl or MgCl_2, which is less than 5% but high rejection to dye molecules. After maintaining the pressure for 6 h, the interception rate for Congo red/mixed salts remained at 98% and that for methyl green/mixed salts was 80%. Further, experiment results show that the stable anti-bacterial rates of loose NF membrane against Escherichia coli and Staphylococcus aureus reached 98.3% and 99.0%, respectively.

中文翻译：

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两性离子接枝壳聚糖制备的具有优异抗生物污染性能的新型松散纳滤膜

背景

开发一种具有零 NaCl 排斥性以及有效的抗粘附和抗菌性能的新型松散 NF 膜对于许多行业的回收和净化应用具有重要意义。

材料和方法

通过交联接枝共聚物壳聚糖-g-聚（磺基甜菜碱甲基丙烯酸酯）（CS-g-PSBMA）作为染料/盐薄膜复合（TFC）膜的选择层，制备了一种新型抗生物污染松散纳滤（NF）膜分离。具体来说，CS-g-PSBMA 是使用铈 (IV) 离子作为氧化剂以引发 CS 的 SBMA 接枝聚合而合成的。将PSF膜用超支化聚乙烯亚胺溶液预润湿，然后在作为支撑层的聚砜（PSf）超滤膜上通过CS-g-PSBMA与戊二醛交联制备松散的NF膜。

结果和讨论

优化后，膜对 NaCl 或 MgCl _{2 的}排斥率最低_，低于 5%，但对染料分子的排斥率很高。保压6 h后，刚果红/混合盐的截留率保持在98%，甲基绿/混合盐的截留率为80%。此外，实验结果表明，松散的NF膜对大肠杆菌和金黄色葡萄球菌的稳定抑菌率分别达到98.3%和99.0%。