膜科学与技术

无机盐体系卷式纳滤膜真实截留率的求取方法

作者：张显球杜明霞王志良张勇贾国正

单位： 1.南京师范大学环境科学与工程系，江苏南京，210046；2.江苏省环境科学研究院，江苏南京，210036

关键词：纳滤膜；真实截留率；浓差极化

出版年,卷(期):页码： 2010,30(6):0-0

摘要：

摘要：在表征纳滤膜分离性能时通常采用真实截留率(R)，然而R不能直接测定，一般借助传质系数通过浓差极化模型求得，因实验条件的差别导致文献报道的计算传质系数的经验方程各异，对卷式膜的有效性也难以确定。本文基于浓差极化理论模型和卷式膜元件的流道结构，结合NF90-2540型卷式纳滤膜元件对NaCl溶液的纳滤实验结果，建立了膜真实截留率的计算公式，为卷式纳滤膜R的求取提供了一种直接方法。同时，实验和分析结果表明，浓差极化程度主要受渗透通量和料液在流道中平均流速的影响：流速较低时，浓差极化程度随渗透通量增加也明显增加，表观截留率(Robs)与R相差明显；随着流速增加，浓差极化程度下降，当流速达到0.2m/s以上时，渗透通量对浓差极化的影响较小，Robs与R可不超过1%。

Abstract: The real retention of membrane is usually used when performances of nanofiltration membrane are characterized . But the real retention is only obtained from mass transfer coefficient at present because it can not be directly measured. It is difficult for correctly calculation the real retention of spiral-wound modules because there are large difference among mass transfer coefficient equations published in literatures. In this paper, based on concentration polarization theoretic model and the flow structure of spiral-wound modules，and combined permeation experiments results with NF90-2540 spiral-wound modules, a equation for calculation the real retention of nanofiltration membrane was established. Meanwhile, the experimental and calculation results showed concentration polarization was mainly controlled by permeation flux and solution velocity in membrane: concentration polarization notably increased at low velocity, and the difference between observed retention and real retention was notable; concentration polarization notably lowered as velocity increasing, and when velocity was higher than 0.2m/s, the difference between observed retention and real retention was small.

张显球（1971—），男，安徽太湖人，博士，副教授，从事水污染控制与膜分离技术研究。

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