MODELING OF ION DIFFUSION INDUCED CURRENT THROUGH A NANOCHANNEL

In this article, a theoretical model that takes into consideration both the diffusion and electric osmosis fluxes to estimate the diffusion current through a nanochannel is proposed. Equivalent impedance of a nanochannel is modeled as a series connection of finite RC circuits. The impedances of the electrical double layer and buffer solution in each infinitesimal RC circuit are represented by a capacitor and a resister, respectively. Due to the electrical double layer effect, the diffusion induced current in the proposed model is position dependent. Computer simulations and experiments using a nanoporous anodic aluminum oxide (AAO) thin film as the filter to separate electrolysis with ion concentration gradient are conducted. A high degree coincidence between the theoretical and experimental data is observed. 1