Abstract
Electrodiffusion of ions in both cation (CEM) and anion exchange membranes (AEM) has been studied with theoretical calculations and experimental studies. Calculations are based on the Finite Element Method (FEM) using COMSOL Multiphysics® software. Nernst-Planck equations are solved in multi-ionic systems where no closed form solutions are available. Simulations are compared with laboratory-scale experiments in terms of current efficiency and membrane selectivity. Simulations revealed unexpected features in transport, due to coupling of ionic fluxes when the local electroneutrality condition is assumed. Transport of weak electrolytes showed the importance of involving ionic equilibria along the concentration profiles in both solutions and membranes, compelling to consider ionic constituents. The advantage of the COMSOL simulations is the ease to find concentration and potential profiles across the entire system, and to split fluxes to diffusion and migration contributions, showing their coupling even in the absence of electric current.
| Original language | English |
|---|---|
| Article number | 100169 |
| Journal | Chemical Engineering Journal Advances |
| Volume | 8 |
| DOIs | |
| Publication status | Published - Aug 2021 |
| MoE publication type | A1 Journal article-refereed |
Funding
This work has received funding from the European Institute of Innovation and Technology (EIT), a body of the European Union, under the Horizon 2020, the EU Framework Programme for Research and Innovation. Project Name and Number: 680652 Credit -18243. SUEZ water technologies and solutions is acknowledged for the supply of the membranes.
Keywords
- Finite element method
- Ion-exchange membranes
- Multi-ionic transport
- Nernst-Planck equation
- Simulation