Active Control of Irreversible Faradic Reactions to Enhance the Performance of Reverse Electrodialysis for Energy Production from Salinity Gradients

Journal Article

Title: Active Control of Irreversible Faradic Reactions to Enhance the Performance of Reverse Electrodialysis for Energy Production from Salinity Gradients

Author:

Oh, Y.; Han, J-Y.; Kim, H.; Jeong, N.; Vermaas, D.; Park, J-S.; Chae, S.

Publication Date:

July 26, 2021

Journal:

Environmental Science & Technology

Volume:

Issue:

Pages:

11388-11396

Publisher:

American Chemical Society

Affiliation:

University of Cincinnati, Korea Institute of Energy Research, Delft University of Technology, Sangmyung University

Technology:

Salinity Gradient, Reverse Electrodialysis

Collection Method:

Lab Data

Engineering:

Control, Performance

Document Access

Website:

External Link

Citation

Oh, Y.; Han, J-Y.; Kim, H.; Jeong, N.; Vermaas, D.; Park, J-S.; Chae, S. (2021). Active Control of Irreversible Faradic Reactions to Enhance the Performance of Reverse Electrodialysis for Energy Production from Salinity Gradients. Environmental Science & Technology, 55(16), 11388-11396. https://doi.org/10.1021/acs.est.1c02734

Abstract

Irreversible faradic reactions in reverse electrodialysis (RED) are an emerging concern for scale-up, reducing the overall performance of RED and producing environmentally harmful chemical species. Capacitive RED (CRED) has the potential to generate electricity without the necessity of irreversible faradic reactions. However, there is a critical knowledge gap in the fundamental understanding of the effects of operational stack voltages of CRED on irreversible faradic reactions and the performance of CRED. This study aims to develop an active control strategy to avoid irreversible faradic reactions and pH change in CRED, focusing on the effects of a stack voltage (0.9–5.0 V) on irreversible faradic reactions and power generation. Results show that increasing the initial output voltage of CRED by increasing a stack voltage has an insignificant impact on irreversible faradic reactions, regardless of the stack voltage applied, but a cutoff output voltage of CRED is mainly responsible for controlling irreversible faradic reactions. The CRED system with eliminating irreversible faradic reactions achieved a maximum power density (1.6 W m^–2) from synthetic seawater (0.513 M NaCl) and freshwater (0.004 M NaCl). This work suggests that the control of irreversible faradic reactions in CRED can provide stable power generation using salinity gradients in large-scale operations.