Our paper entitled: The Permselectivity and Water Transference Number of Ion Exchange Membranes in Reverse Electrodialysis has been accepted for publication in the Journal of membrane science. Ion exchange membranes are the main components of equipment to perform reverse electrodialysis, i.e. to produce electricity from the mixing of fresh-water (from rivers) and sea-water. In the article, we show that the water transference number of ion exchange membranes plays an important role in deciding their selectivity, and hence the efficiency of cells for reverse electrodialysis. We have measured the transport numbers of sodium, chloride and water in ion exchange membranes from Fumatech. Using the measured transport numbers, we demonstrate that a route to improve the selectivity of ion exchange membranes, and hence the performance of cells for reverse electrodialysis is to have a water transference number as close to zero as possible. This can possibly be achieved by constructing hydrophobic membranes. The work is an important step towards making saline power available, and was performed in collaboration with Agnieszka Zlotorowicz, Robin V. Strand, Odne S. Burheim and Signe Kjelstrup from NTNU.
