A modified Donnan–steric-pore model for predicting flux and rejection of dye/NaCl mixture in nanofiltration membranes
A modified Donnan–steric-pore model for predicting flux and rejection of dye/NaCl mixture in nanofiltration membranes
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DOI：
10.1081/ss-120002238
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发表时间：
2002-03
影响因子：
2.8
通讯作者：
A. Mohammad
中科院分区：
文献类型：
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作者：
A. Mohammad
基于扩展的Nernst-Planck方程，考虑了离子在膜内传输的电荷效应和空间效应，以及带电离子/溶质混合物的浓差极化效应，提出了一种修正的Donnan-steric-pore模型（DSPM），用于预测纳滤膜对无机盐/带电有机物混合物的截留率。利用这种方法，可以基于膜表面处的离子/带电溶质的浓度来计算渗透通量。使用三个参数对膜性能进行建模，即：有效孔半径r p;膜厚度与孔隙率的有效比Δx/A k;和有效电荷密度X d。基于该模型的计算结果与已发表的实验数据的比较表明，该模型可以预测的趋势和模式的排斥和通量减少行为合理地含有NaCl-染料-H2O的系统。利用该模型研究了传质膜厚度、染料价态、染料扩散系数和染料/盐浓度比等系统变量对通量和NaCl截留率的影响。该模型可以作为初步的工具来评估纳滤膜对二元溶液和混合物的截留能力以及通量行为。
This paper presents a modified Donnan–steric-pore model (DSPM) to predict the rejection of mixture of salts/charged organic in nanofiltration (NF) membranes, based on the extended Nernst–Planck equation with the incorporation of charge and steric effects for the transport of ions inside the membrane, and incorporation of concentration polarization effect for a mixture of charged ions/solutes. With this approach, the permeate flux can be calculated based on the concentration of ions/charged solutes at the membrane surface. The membrane performance was modeled using three parameters, namely: effective pore radius, r p; effective ratio of membrane thickness to porosity, Δx/A k; and the effective charge density, X d. Comparison of the calculation based on the model with published experimental data shows that the model can predict the tendencies and patterns of rejection and flux reduction behavior reasonably well for systems containing NaCl–dye–H2O. Effects on fluxes and NaCl rejections of system variables such as mass transfer film thickness, dye valence, dye diffusivity, and dye/salt concentration ratio were studied using this model. This model can be used as a preliminary tool to assess the rejection capability as well as the flux behavior of NF membranes towards binary solution and mixtures.