%A Feng Zhang, Lu Tan, Li Gong, Shuqi Liu, Wangxi Fang, Zhenggong Wang, Shoujian Gao, Jian Jin %T Ionic strength directed self-assembled polyelectrolyte single-bilayer membrane for low-pressure nanofiltration %0 Journal Article %D 2022 %J Front. Chem. Sci. Eng. %J Frontiers of Chemical Science and Engineering %@ 2095-0179 %R 10.1007/s11705-021-2093-3 %P 699-708 %V 16 %N 5 %U {https://journal.hep.com.cn/fcse/EN/10.1007/s11705-021-2093-3 %8 2022-05-15 %X

Layer-by-layer assembly is a versatile technique for fabricating nanofiltration membranes, where multiple layers of polyelectrolytes are usually required to achieve reasonable separation performance. In this work, an ionic strength directed self-assembly procedure is described for the preparation of nanofiltration membranes consisting of only a single bilayer of poly(diallyldimethylammoniumchloride) and poly(sodium-4-styrenesulfoate). The influence of background ionic strength as well as membrane substrate properties on the formation of single-bilayer membranes are systematically evaluated. Such a simplified polyelectrolyte deposition procedure results in membranes having outstanding separation performance with permeating flux of 14.2 ± 1.5 L∙m–2∙h–1∙bar–1 and Na2SO4 rejection of 97.1% ± 0.8% under a low applied pressure of 1 bar. These results surpass the ones for conventional multilayered polyelectrolyte membranes. This work encompasses an investigation of ionic strength induced coiling of the polyelectrolyte chains and emphasizes the interplay between-polyelectrolyte chain configuration and substrate pore profile. It thus introduces a new concept on the control of membrane fabrication process toward high performance nanofiltration.