Investigating Saltwater Desalination by Electrodialysis and Curriculum Extensions To Introduce Students to the Chemical Physics of Polymeric Ion-Exchange Membranes

Even though our planet contains large reservoirs of water as oceans, access to drinking water is a global concern because large amounts of salt are fatal to humans. While electrochemical desalination, that is, electrodialysis, is a process that is capable of generating potable water from salt water, most chemistry curricula do not teach this process. Therefore, we developed a curriculum and accompanying low-cost activity to expose students from middle school to undergraduate studies to the concept of electrodialysis and the importance of polymeric ion-exchange membranes in the electrodialysis process. The curriculum provides background by introducing the students to issues of water access, current state-of-the-art solutions and the scenarios where they are optimal, and the urgent need for alternative and innovative processes for clean, potable water generation. The concepts and techniques presented in this curriculum cover those relevant to desalination, which encompass several physical phenomena that span multiple disciplines. The supporting activity that accompanies this curriculum allows students to perform electrodialysis and monitor the progress of the reaction using common pH indicators, which inherently includes many concepts that are relevant to general chemistry. The scientific depth of this curriculum is easily adjusted to challenge students at various levels of expertise.