Self-assembly of inner skin hollow fiber polyelectrolyte multilayer membranes by a dynamic negative pressure layer-by-layer technique
Self-assembly of inner skin hollow fiber polyelectrolyte multilayer membranes by a dynamic negative pressure layer-by-layer technique
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DOI：
10.1016/j.memsci.2008.07.016
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发表时间：
2008-11
影响因子：
9.5
通讯作者：
Guojun Zhang;Xuejing Song;S. Ji;Naixin Wang;Zhong-zhou Liu
中科院分区：
文献类型：
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作者：
Guojun Zhang;Xuejing Song;S. Ji;Naixin Wang;Zhong-zhou Liu
在过去的研究中，静电逐层（LbL）吸附带相反电荷的聚电解质已被证明是一种很有前途的方法，用于制备多层膜（PEMMs）。到目前为止，这种方法主要用于组装平板和管状膜。由于中空纤维膜具有一些优点，如高填充密度，独立的机械支持，因此随之而来的经济优势，因此，本研究试图通过使用动态LbL吸附技术组装内层中空纤维PEMMs。采用聚丙烯酸（PAA）和聚乙烯亚胺（PEI）在水解聚丙烯腈（PAN）中空纤维膜上交替动态过滤的方法，在负压条件下成功地实现了组装过程。在95 wt.%的渗透蒸发分离的情况下，在乙醇-水混合物（50°C）中，仅用4.5和6.5双层获得的膜的分离因子分别为245和1338，而渗透通量分别为290和120 g/（m2 h）。考察了以叔丁醇、异丙醇和乙醇为醇类的不同醇/水混合物的渗透汽化分离行为。最后，扫描电子显微镜和原子力显微镜清楚地证实了在中空纤维支撑体的内表面上形成的均匀且无缺陷的层。由于可以使用不同的双金属对来组装不同用途的PEMM，因此预计动态负压LbL吸附技术也可以潜在地用于制备其他领域中的多种类型的PEMM。
In the past studies, electrostatic layer-by-layer (LbL) adsorption of oppositely charged polyelectrolytes has proven to be a promising method for the preparation of polyelectrolyte multilayer membranes (PEMMs). Till now, this method was mainly used to assemble flat sheet and tubular membranes. Since hollow fiber membrane has some advantages such as high-packing density, self-contained mechanical support and hence the consequent economical superiority, this study therefore seeked to assemble inner skin hollow fiber PEMMs by using a dynamic LbL adsorption technique. The assembly process was successfully accomplished by alternatively dynamically filtrating polyacrylic acid (PAA) and polyethyleneimine (PEI) on a hydrolyzed hollow fiber polyacrylonitrile (PAN) membrane under a negative pressure condition. In the case of pervaporation separation of 95wt.% ethanol–water mixture (50°C), the membrane obtained with only 4.5 and 6.5 bilayers had separation factor of 245 and 1338 while the permeate fluxes were 290 and 120g/(m2h), respectively. The pervaporation separation behavior of various alcohol/water mixtures with the alcohols being t-butanol, 2-propanol and ethanol were also investigated. Finally, scanning electron microscopy and atomic force microscopy clearly confirms a uniform and defect-free layer formed on the inner surface of hollow fiber support. Since different polyelectrolyte pairs could be used to assemble PEMMs for different uses, it was expected that the dynamic negative pressure LbL adsorption technique could also potentially be used to prepare many types of PEMMs in other fields.