Fabrication, characterization, and optimization of porous electrodes for electrochemical desalination

Faradaic deionization (FDI) is an emerging technique for the removal of salt ions from water due to Faradaic electrodes, such as those composed of Prussian blue analogues (PBAs), having high ion storage capacity. However, when compared with desalination technologies such as reverse osmosis, FDI is currently limited by impractically high energy consumption and low salt removal. The work in this dissertation is focused on reducing FDI energy consumption per unit salt removed by modifying the electrodes and surrounding desalination system to increase electronic conductivity, ionic conductivity, hydraulic permeability, and active material utilization of PBA electrodes. These modifications range in scale from control over colloidal forces between constituent microscopic particles in the electrode slurry, increasing electrode density, laser-milling of macroscopic ion-conducive patterns into the electrode, flow-through electrode cell design, and construction of an automated recirculating fluid system. Iterations were made as these techniques were developed, with experimental studies testing the reduction of energy consumption over previous designs and leading to the creation of an automated recirculating FDI cell using dense, patterned, highly conductive intercalation electrodes with an eightfold greater electrode area than the initial cell. This novel system can remove more than half the salt from influent with salinity comparable to seawater while achieving a thermodynamic energy efficiency of over 50%, far exceeding the performance of previous FDI systems. Higher removal rates are achievable at the cost of greater energy consumption, however experimental results demonstrate that FDI can be a highly efficient desalination technology. The combination of enhancements at every scale of the system has addressed the most significant practical challenges of FDI and brought the technology closer to viability.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2021

Author dc:creator

• Reale, Erik

Contributors dc:contributor

• Smith, Kyle C
• Dillon, Shen
• Miljkovic, Nenad
• Juarez, Gabriel

• Desalination Porous Electrodes

Statement dc:rights

• Copyright 2021 Erik Reale

Language dc:language

en

Handle dc:identifier

https://hdl.handle.net/2142/117885

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/117885