Modelling Charge-selective Membranes Using Poisson-Nernst-Planck Equations

Abstract

Charge-selective membranes play an important role in reverse electro dialysis (RED), which is a process to extract energy from the mixing of fresh and salt water. This thesis begins by deriving the classical limiting current for charge-selective membranes. We then look at modelling a charge-selective membrane using the Poisson-Nernst-Planck system and solve this system numerically. We find results in agreement with the literature, including the emergence of a so called extended space charge. Lastly other literature on the dynamics of currents through a membrane and additional physical mechanism causing over-limiting current are briefly discussed.