Zhou Wenwen, Song Lianfa
Centre for Water Research, Department of Civil Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260.
Environ Sci Technol. 2005 May 1;39(9):3382-7. doi: 10.1021/es0403561.
Water flux and salt rejection rate, which are the two most important parameters in evaluating the performance of a reverse osmosis membrane process, are desirable to be directly related to the membrane properties and operating conditions. However, the membrane transport theories in their general forms are unable to describe the membrane performance satisfactorily. In this study, water and salt fluxes through reverse osmosis membranes were carefully examined with a cross-flow filtration cell under various operating conditions. Experimental results showed that a notable permeate flux was detected when the driving pressure was smaller than the feed osmotic pressure. Water flux increased with the driving pressure nonlinearly before approaching a linear relation with the pressure. In addition, salt transport was highly dependent on both operating pressure and feed salt concentration. A power relationship between salt flux and concentration was correlated well with the experimental data. The equations for water and salt fluxes obtained from this work would provide a facile and accurate means for predicting the membrane performance in design and optimization of reverse osmosis processes.
水通量和脱盐率是评估反渗透膜过程性能的两个最重要参数，它们希望能直接与膜性能和操作条件相关。然而，一般形式的膜传输理论无法令人满意地描述膜性能。在本研究中，使用错流过滤池在各种操作条件下仔细研究了通过反渗透膜的水和盐通量。实验结果表明，当驱动压力小于进料渗透压时，检测到显著的渗透通量。在与压力接近线性关系之前，水通量随驱动压力呈非线性增加。此外，盐传输高度依赖于操作压力和进料盐浓度。盐通量与浓度之间的幂关系与实验数据相关性良好。从这项工作中获得的水通量和盐通量方程将为在反渗透过程的设计和优化中预测膜性能提供一种简便而准确的方法。
