膜科学与技术

垫片法对正渗透过程中浓差极化的改善研究

作者：程世营张捍民，杨凤林

单位：大连理工大学环境学院工业生态与环境工程教育部重点实验室，中国辽宁大连 116024

关键词：正渗透；内浓差极化；垫片位置；

出版年,卷(期):页码： 2015,35(1):49-55

摘要：

正渗透过程中存在的浓差极化现象对其实际的水通量运行效果影响显著。本文在不增加能耗的前提下提出了一种简易的垫片法来改善正渗透过程中出现的浓差极化现象。利用这种方法，在正渗透膜活性层朝向原料液的膜取向下，发现垫片安置在汲取液廊道贴紧膜的位置可以最好的减缓稀释内浓差极化，进而显著的提升正渗透的运行效果；此时，以0.5M的NaCl为原料液，而分别以1M、2M、4M的NaCl为汲取液进行批式实验，与未安置垫片的方式相比，水通量分别有2.94 %, 9.0 % 和 12.5 %的提升幅度；另外，还发现当将垫片放置在原料液廊道（远离膜）和汲取液廊道（贴紧膜）时，可以起到同时减缓浓缩外浓差极化(CECP)和稀释内浓差极化(DICP)的效果。

A major barrier to use asymmetric membranes for forward osmosis (FO) process is concentration polarization (CP) which dramatically reduces the real performance of FO. The scope of this study was to provide a simple method of mitigating CP, especially dilutive internal CP, in the absence of additional energy consumption and investigate the impact of spacer location on concentrative external CP and dilutive internal CP which occurred in FO (AL-FW) mode; finally we tried to provide a spacer location that could significantly decrease the adverse effect of CP on FO performance. These findings of the research led the author to the conclusion that in FO mode, placing the spacer in the draw channel with one end connecting the membrane could well mitigate dilutive ICP. Under such conditions when the feed solution was 0.5M NaCl while the draw solution was 1M, 2M and 4M NaCl separately, the average water flux could increase by 2.94 %, 9.0 % and 12.5 % respectively. Besides, placing the spacer in both feed (away from the membrane) and draw channels (in contact with the membrane) could be an acceptable method of decreasing the negative effects of concentrative ECP and dilutive ICP simultaneously.

张捍民(1973-)，女，教授，博士，博士生导师，研究方向为水污染控制、膜法水处理等，(电话)0411-84706173 (电子邮箱)zhanghm@dlut.edu.cn],

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