CARRIER-MEDIATED TRANSPORT THROUGH BULK LIQUID MEMBRANES - DEPENDENCE OF TRANSPORT RATES AND SELECTIVITY ON CARRIER PROPERTIES IN A DIFFUSION-LIMITED PROCESS
CARRIER-MEDIATED TRANSPORT THROUGH BULK LIQUID MEMBRANES - DEPENDENCE OF TRANSPORT RATES AND SELECTIVITY ON CARRIER PROPERTIES IN A DIFFUSION-LIMITED PROCESS
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DOI：
10.1021/ja00287a043
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发表时间：
1985-01-01
影响因子：
15
通讯作者：
LEHN, JM
中科院分区：
文献类型：
--
作者：
BEHR, JP;KIRCH, M;LEHN, JM
一个扩散限制动力学处理被施加到载体介导的运输的一个单一的基板物种和一个离子对和载体介导的交换扩散2基板对一个回输物种。进行了大量的数值模拟，以描述的载体-基板对的热力学性质（萃取平衡）的传输速率和选择性的关系。运输率显示一个钟形的依赖平衡提取常数;它们减少时，要么是太少的基板提取在入口处或太多的提取在出口处的膜设置;域的运输是最佳的依赖于所涉及的特定过程和实验条件。在不同的基板之间的给定的载体的运输选择性的测定需要直接的竞争实验，运输选择性接近热力学提取选择性只有当有很少的复杂的形成在出口界面。这种处理被施加到一些文献结果上的运输通过液膜，涉及广泛不同的基板，载体和实验条件;扩散限制过程帐户在一个简单的方式为实验数据，没有必要调用一个机制，运输是有限的络合动力学。
A diffusion-limited kinetic treatment was applied to carrier-mediated transport of a single substrate species and of an ion pair and to carrier-mediated exchange diffusion of 2 substrates against a back-transported species. Extensive numerical simulation was performed in order to describe the relation of transport rates and selectivities with thermodynamic properties (extraction equilibria) of the carrier-substrate pairs. Transport rates display a bell-shaped dependence on equilibrium extraction constants; they decrease when there is either too little substrate extraction at the entry or too much extraction at the exit of the membrane set-up; the domain over which transport is optimal depends on the particular process involved and on the experimental conditions employed. The determination of transport selectivities of a given carrier between different substrates requires direct competition experiments, transport selectivities being close to thermodynamic extraction selectivities only when there is little complex formation at the exit interface. This treatment was applied to a number of literature results on transport through liquid membranes, involving widely different substrates, carriers and experimental conditions; the diffusion-limited process accounts in a straightforward fashion for the experimental data and there is no need to invoke a mechanism where transport is limited by complexation kinetics.