Effect of multivalent ions on electroosmotic flow in micro- and nanochannels
Effect of multivalent ions on electroosmotic flow in micro- and nanochannels
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DOI：
10.1002/elps.200305561
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发表时间：
2003-09-01
期刊：
影响因子：
2.9
通讯作者：
Conlisk, AT
中科院分区：
文献类型：
--
作者：
Zheng, Z;Hansford, DJ;Conlisk, AT
在这项工作中，研究了多价离子对多种电解质成分的电渗流的影响。研究的案例包括将 Ca2+ 和 HPO42- 以及其他一价离子（例如 K+ 和 H2PO4-）掺入 NaCl 水溶液中。推导并数值求解控制方程。控制方程的边界条件是根据电化学平衡要求获得的。与单价离子相比，结果表明，在具有固定表面电荷的微通道和纳米通道中，多价反离子即使数量非常少，也会显着降低电渗流，而多价共离子对电渗流影响很小。由于离子-壁相互作用增强，多价抗衡离子构成了双电层 (EDL) 中的大部分离子，导致表面净电荷减少。
In this work, the effect of multivalent ions on electroosmotic flow is investigated for multiple electrolyte components. The cases studied include incorporating Ca2+ and HPO42- and other monovalent ions, such as K+ and H2PO4-, into an aqueous NaCl solution. The governing equations are derived and solved numerically. The boundary conditions for the governing equations are obtained from the electrochemical equilibrium requirements. In comparison with monovalent ions, the results show that in micro- and nanochannels having fixed surface charges, multivalent counterions, even in very small amounts, reduce electroosmotic flow significantly, while the multivalent co-ions have little effect on the electroosmotic flow. Due to the enhanced ion-wall interactions multivalent counterions compose the majority of ions in the electric double layer (EDL), causing a decrease of net charge at the surface.