Multi-ion diffusiophoresis
Multi-ion diffusiophoresis
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DOI：
10.1016/j.jcis.2014.03.003
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发表时间：
2014-06-15
影响因子：
9.9
通讯作者：
Velegol, Darrell
中科院分区：
文献类型：
--
作者：
Chiang, Tso-Yi;Velegol, Darrell
带电粒子的运动通过扩散电泳机制在盐浓度梯度中发生。目前的分析模型扩散电泳已开发的对称Z：Z电解质在稳态下产生的梯度。最近，我们的实验室报告了由于溶解碳酸钙（CaCO 3）产生三种离子（Ca 2+，HCO 3-和OH-）的扩散渗透流，这种流体运动不能用当前的分析模型来描述。在这篇文章中，我们推导出了涉及多个不同价态离子的梯度中的扩散渗流的表达式，假设无限薄的双层。我们还数值求解了三离子情况下随时间变化的浓度分布，发现溶液中HCO 3-的浓度分布是非单调的。最后，我们定量地检验了溶液中电中性的假设，发现即使对于多离子的情况，电中性也是一个很好的近似，这表明我们从离子迁移方程导出的电场是相当准确的。(C)由Elsevier Inc.出版。
The movement of charged particles occurs in a salt concentration gradient by the mechanism of diffusiophoresis. Current analytical models for diffusiophoresis have been developed for a gradient generated by a symmetric Z:Z electrolyte at steady state. Recently, our lab has reported diffusioosmotic flows due to dissolving calcium carbonate (CaCO3) which generates three ions (Ca2+, HCO3-, and OH-), and this fluid motion cannot be described by current analytical models. In this communication, we derive an expression for the diffusioosmotic flow in a gradient involving multiple ions of different valences, assuming infinitesimally thin double layers. We also solve numerically the time-dependent concentration profiles for the three-ion case and find that the concentration profile of HCO3- is non-monotonic in solution. Finally, we examine quantitatively the assumption of electroneutrality in solution, finding that electroneutrality is a good approximation even for the multi-ion case, indicating that our electric field derived from the ion migration equation is quite accurate. (C) 2014 Published by Elsevier Inc.