Desalination Through the Extensional Flow of Polyelectrolytes

Abstract

As the earth begins to face increased water scarcity, methods to produce freshwater such as desalination are becoming ever more important. These desalination techniques must be energy efficient, economical, and scalable in order to implement them on a widespread scale. To meet these demands, we hypothesized the use of extended polyelectrolytes to capture and remove salt. We investigated how inducing an extensional flow in a solution of water, salt, and polyelectrolytes could stretch the polyelectrolytes, exposing more charge sites and attracting the oppositely charged salt ions. Then, these polyelectrolytes and the captured salt ions could be filtered out, decreasing the salt concentration of the solution. The efficacy of this method was compared to passing the solution through the membrane without extension. Implementation of the proposed method given the limitations of the experiment setup proved to be less effective than the control process at separating salt from water.