Experimental Study on Ion Transport in Microfluidic Electrodialysis Using Partially Masked Ion Exchange Membranes.

Junsu Jang,Bumjoo Kim,Minseok Kim,Minsung Kim,Daejong Yang,Joonghan Shin

doi:10.3390/mi13030356

Junsu Jang, Bumjoo Kim + Show 4 more

Open Access

https://doi.org/10.3390/mi13030356

Copy DOI

Abstract

Electrodialysis using anion-exchange membranes (AEMs) and cation-exchange membranes (CEMs) has been widely used for water desalination and the management of various ionic species. During commercial electrodialysis, the available area of an ion-exchange membrane is reduced by a non-conductive spacer that is in contact with the AEM/CEM. Although multiple reports have described the advantages or disadvantages of spacers, fewer studies have explored the effects of spacers on the mass transport effect of the reduced membrane area excluding the fluid flow change. In this paper, we present our experimental studies concerning mass transport in microfluidic electrodialysis systems with partially masked ion-exchange membranes. Six different types of masking membranes were prepared by the deposition of non-conductive films on parts of the membranes. The experimental results showed that the overlapped types (in which masking was vertically aligned in the AEM/CEM) exhibited a larger electrical conductance and better current/energy efficiency, compared with the non-overlapped types (in which masking was vertically dislocated in the AEM/CEM). We also observed that a reduction in the unit length of the unmasked ion-exchange membrane enhanced overall mass transport. Our results demonstrate the effects of patterned membranes on electrical resistance and desalination performance; they also identify appropriate arrangements for electromembrane systems.

Highlights

Ion-exchange membranes featuring many nanopores have attracted considerable attention from researchers in various fields; such membranes exhibit unique mass transport characteristics and ion selectivity
We experimentally explored the effects of partially masked ion-exchange membranes on the electrical responses and current/energy efficiency of electrodialysis
Non-conductive tive masking film was patterned onto membranes with or without vertical alignment masking film was patterned onto membranes with or without vertical alignment (over(overlapped or non-overlapped) of the anion-exchange membranes (AEMs)/cation-exchange membranes (CEMs)

Summary

Introduction

Ion-exchange membranes featuring many nanopores have attracted considerable attention from researchers in various fields; such membranes exhibit unique mass transport characteristics and ion selectivity. Workers in the field of eco-friendly and renewable energy commonly use ion-exchange membranes during the analysis of fuel cells, redox flow batteries, electrodialysis, and reverse electrodialysis [1,2,3,4]. Electrodialysis is a mature technology; desalination employs ion-exchange membranes [2,3,4]. Electrodialysis (which is driven by electrical energy) is simple, scalable, and controllable; it efficiently treats brackish water [5]. A conventional electrodialysis system features ion-exchange membranes, electrodes, a spacer, and fluidic compartments; it operates via the electrophoretic migration of cationic/anionic species (driven by an electric field) through permselective membranes [2].

Methods

Results

Conclusion