Electrostatic cooling in Ion-Exchange Membranes

TL;DR

This paper explores electrostatic heating and cooling phenomena in ion-exchange membranes, focusing on the effects of electrical double layers and pressure differences on temperature regulation during ion and water transport.

Contribution

It introduces the concept of electrostatic cooling in ion-exchange membranes and analyzes the thermal effects associated with EDLs and pressure-driven flows.

Findings

Electrostatic effects can cause cooling in EDLs during ion transport.

Pressure differences across EDLs induce heating or cooling effects.

Electrostatic phenomena significantly influence thermal management in membrane processes.

Abstract

In ion-exchange membrane processes, ions and water flow under the influence of gradients in hydrostatic pressure, ion chemical potential, and electrical potential (voltage), leading to solvent flow, ionic fluxes and ionic current. At the outer surfaces of the membranes, electrical double layers (EDLs) are formed (Donnan layers). When a current flows through the membrane, we argue that besides Joule heating in the bulk of the membrane and in the electrolyte outside the membrane, there is also electrostatic heating and cooling in the EDLs. In addition, when fluid flows through a charged membrane, at the outsides of the membrane there is pressure-related heating or cooling due to the osmotic and hydrostatic pressure differences across the EDLs.