Abstract:
Electrochemical impedance and chronopotentiometric measurements with Na+-selective solvent polymeric (PVC) membranes containing a neutral ionophore and a cation exchanger revealed low-frequency resistance, which is ascribed to Na+ ion transfer across the interface between the membrane and aqueous solution. The attribution is based on the observed regular dependence of this resistance on the concentration of Na+ in solutions. The respective values of the exchange current densities were found to be significantly larger than the currents flowing through ion-selective electrodes (ISEs) during an analysis in non-zero-current mode. This fact suggests that the interfacial electrochemical equilibrium is not violated by the current flow and implies that the Nernst equation can be applied to interpret the data obtained in non-zero-current mode, e.g., constant potential coulometry.
摘要:
使用含有中性离子载体和阳离子交换剂的Na选择性溶剂聚合物(PVC)膜进行的电化学阻抗和计时电位测量显示出低频电阻,这归因于Na+离子跨膜和水溶液之间的界面转移。归属基于观察到的该电阻对溶液中Na浓度的规律依赖性。在非零电流模式的分析过程中,发现交换电流密度的相应值明显大于流过离子选择电极(ISE)的电流。这一事实表明,界面电化学平衡不会被电流破坏,并且意味着可以应用能斯特方程来解释在非零电流模式下获得的数据。例如,恒电位库仑法.