The effect of gel layer thickness on the salt rejection performance of polyelectrolyte gel-filled nanofiltration membranes
The effect of gel layer thickness on the salt rejection performance of polyelectrolyte gel-filled nanofiltration membranes
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DOI：
10.1016/j.memsci.2006.12.029
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发表时间：
2007-03
影响因子：
9.5
通讯作者：
S. Suryanarayan;A. M. Mika;R. F. Childs
中科院分区：
文献类型：
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作者：
S. Suryanarayan;A. M. Mika;R. F. Childs
从理论和实验两个方面研究了凝胶层厚度对带正电荷的微孔纳滤膜盐分离的影响。扩展的能斯特-普朗克（ENP）方程与Teorell-Meyer-Sievers（TMS）模型耦合用于计算具有在纳滤应用中通常使用的范围内的凝胶密度的膜的压力驱动的氯化钠截留率。结果表明，膜（凝胶层）的厚度对盐截留率有很大的影响，当凝胶层厚度达到50-75μm时，盐截留率迅速增加。超过该点进一步增加厚度对盐截留率的影响要小得多。通过制备一系列具有不同密度的交联聚（3-丙烯酰胺丙基）-三甲基氯化铵（PAPTAC）凝胶的薄微孔聚乙烯（PE）支持物的孔内的膜，实验检查理论预测。膜的特征在于它们的聚合物体积分数（凝胶浓度），厚度和有效电荷密度。通过使用单个膜和两个膜的堆叠来检查膜厚度的影响。在50- 550 kPa压力范围内测定了膜和膜堆的纯水通量和脱盐率。膜的单盐截留率与膜或膜堆的厚度密切相关，与计算的膜的盐截留率完全雅阁。
The effect of gel layer thickness on salt separation of positively charged pore-filled nanofiltration membranes has been examined both theoretically and experimentally. The extended Nernst-Planck (ENP) equation coupled with the Teorell-Meyer-Sievers (TMS) model were used to calculate the pressure-driven sodium chloride rejections for membranes having gel densities in the range typically used in nanofiltration applications. It was found that salt rejection was dependent on membrane (gel-layer) thickness with salt rejections increasing rapidly with thickness up to 50–75μm. Further increases in thickness beyond this point had a much smaller effect on salt rejection. The theoretical predictions were examined experimentally by preparing a series of membranes with cross-linked poly(3-acrylamidopropyl)-trimethylammonium chloride (PAPTAC) gels with varying densities within the pores of a thin microporous polyethylene (PE) support. The membranes were characterized by their polymer volume fractions (gel concentration), thicknesses and effective charge densities. The effect of membrane thickness was examined by using single and stacks of two membranes. The pure water fluxes and salt rejections of the membranes and membrane stacks were determined in the pressure range 50–550kPa. The single salt rejections of the membranes which were very dependent on the thickness of the membrane or membrane stack, were fully in accord with the calculated salt rejections of the membranes.