High Performance Water Desalination Using Propagating Ion Concentration Shock Waves

Stanford University, Stanford CA

Investigators

Abstract

This NSF award by the Chemical and Biological Separations program supports work by Professor Juan Santiago at Stanford University to develop highly efficient sea and brackish water desalination (ion removal) devices. Currently, the US faces simultaneous population growth and a decline in freshwater resources, so that desalination will become increasingly important towards realizing sustainable water management. However, current desalination methods suffer from high energy and/or infrastructure costs. In an effort to develop new methods which reduce these costs, Santiago's group is researching ion concentration shock waves created by concentration polarization. Concentration polarization arises when an electric field is applied across specialized membranes called ion exchange membranes. This concentration polarization describes the creation of a region of enriched ion concentration on one side of the membrane, and the associated creation of a region of depleted (desalinated) ion concentration on the opposite side of the membrane. The waves of interest are sharp, moving interfaces which bound growing regions of ion enrichment and depletion. The Santiago group will focus on performing controlled experiments and developing models of key phenomena, which will be utilized to develop highly efficient devices. The group will develop prototype desalination devices which generate small, test-amounts of desalinated water. The group will engage undergraduate students and incorporate material from this research into engineering curriculum courses.