无机盐体系卷式纳滤膜真实截留率的求取方法  

A method for obtaining the real retention of nanofiltration membrane

作　　者：张显球[1] 杜明霞[1] 王志良[2] 张勇[1] 贾国正[1] 

机构地区：[1]南京师范大学环境科学与工程系,南京210046 [2]江苏省环境科学研究院,南京210036

出　　处：《膜科学与技术》2010年第6期93-96,共4页Membrane Science and Technology

基　　金：江苏省环保厅基金资助项目(200802);江苏省环境工程重点实验室开放课题(KF2009006)

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.文章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0.2 m/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%.The real retention of membrane is usually used when performances of nanofiltration membrane are characterized.The real retention is only obtained from mass transfer coefficient at present since it can not be directly measured.It is difficult for correctly calculating the real retention of spiral-wound modules as 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 that 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 remarkable;concentration polarization lowered as velocity increasing,and when velocity was higher than 0.2 m/s,the difference between observed retention and real retention was small.

关 键 词：纳滤膜 真实截留率 浓差极化 

分 类 号：TQ028.8[化学工程]