An Attempt to Formulate a Quantitative Theory of Membrane Permeability
An Attempt to Formulate a Quantitative Theory of Membrane Permeability
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建立膜渗透性定量理论的尝试
DOI：
10.3181/00379727-33-8339c
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发表时间：
1935
影响因子：
--
通讯作者：
T. Teorell
中科院分区：
文献类型：
--
作者：
T. Teorell
电解质扩散的基本理论（Nernst，1 Planck 2）考虑了静电力与“渗透”力共同导致离子迁移。然而，在这些理论中，不必对溶液中粒子的电荷来源做出假设。因此，我们可以预期，他们关于离子扩散的预测可能会扩展到包括其他扩散情况，其中存在其他带电元素，无论这些元素的构成、形状等如何。电解质通过膜的扩散可能就是这种情况。由于“吸附”、“解离”或“极性特征”等，膜可以被认为具有电荷，但没有必要对其性质做出任何进一步的假设。膜的作用被认为是“添加离子”的作用。为了证明将渗透性问题视为简单扩散的有用性，为了清楚起见，以高度简化的方式，尝试证明当 NaCl 扩散穿过“负”膜时所谓的“浓度效应”在理论上是可预测的：从膜的一侧，活性为 1 的 NaCl 扩散到活性为 2 的另一侧。膜可以表示为由活性为 X 的负的、固定离子组成，假设为整个膜上保持恒定。在稳定状态下，膜表面层的离子活性可以是Na1、Cl1和Na2、Cl2。对于电中性，可以假设 Na1 = (Cl1 + X) 和 Na2 = (Cl2 + X)。尽管膜中 Na 的浓度与 Cl 的浓度不同，但通量将相等，因为作用在它们上的力（“渗透”加电）不相等。
The fundamental theories of electrolyte diffusion (Nernst, 1 Planck 2 ) take into account the electrostatic forces that coöperate with the “osmotic” forces to cause the migration of ions. In these theories, however, no assumption has to be made as to the origin of the charge on the particles in the solution. Accordingly, we may expect that their predictions regarding ionic diffusion may be extended to include other cases of diffusion, where other charged elements are present, regardless of the constitution, shape, etc., of these elements. Diffusion of an electrolyte through a membrane may be such a case. The membrane may be regarded as having a charge due either to “adsorption,” “dissociation,” or “polar character,” etc., but it is not necessary to make any further assumptions as to its nature. The effect of the membrane is regarded as that of an “added ion.” In order to demonstrate the usefulness of treating permeability problems as cases of simple diffusion we shall—for the sake of clarity, in a highly simplified way—try to show that the so-called “concentration effect” when NaCl diffuses across a “negative” membrane is theoretically predictable: From one side of the membrane, NaCl, having the activity a 1, diffuses to the other side where the activity is a 2. The membrane may be represented as consisting of negative, immobile ions of the activity X, which is assumed to be constant throughout the membrane. In the steady state the ionic activities in the membrane surface layers may be Na1, Cl1 and Na2, Cl2. For electroneutrality it may be assumed that Na1 = (Cl1 + X) and Na2 = (Cl2 + X). Although the concentration of Na in the membrane differs from that of Cl the flux will be equal because the forces (“osmotic” plus electrical) operating on them are not equal.