PRESSURE-DRIVEN STABILIZATION OF CAPACITIVE DEIONIZATION

Author

Landon S. Caudill, University of KentuckyFollow

Date Available

4-25-2018

Year of Publication

2018

Document Type

Master's Thesis

Degree Name

Master of Science in Mechanical Engineering (MSME)

College

Engineering

Department/School/Program

Mechanical Engineering

Advisor

Dr. Kunlei Liu

Abstract

The effects of system pressure on the performance stability of flow-through capacitive deionization (CDI) cells was investigated. Initial data showed that the highly porous carbon electrodes possessed air/oxygen in the micropores, and the increased system pressure boosts the gases solubility in saline solution and carries them out of the cell in the effluent. Upon applying a potential difference to the electrodes, capacitive-based ion adsorption occurs in competition with faradaic reactions that consume oxygen. Through the addition of backpressure, the rate of degradation decreases, allowing the cell to maintain its salt adsorption capacity (SAC) longer. The removal of oxygen from the pore space of the electrodes makes it no longer immediately accessible to faradaic reactions, thus hindering the rate of reactions and giving the competing ion adsorption an advantage that is progressively seen throughout the life of the cell. A quick calculation shows that the energy penalty to power the pump is fairly insignificant, especially in comparison to the cost of replacing the electrodes in the cell. Thus, operating at elevated pressures is shown to be cost effective for continuous operation through the reduced electrode replenishment costs.

Digital Object Identifier (DOI)

https://doi.org/10.13023/ETD.2018.122

Recommended Citation

Caudill, Landon S., "PRESSURE-DRIVEN STABILIZATION OF CAPACITIVE DEIONIZATION" (2018). Theses and Dissertations--Mechanical Engineering. 113.
https://uknowledge.uky.edu/me_etds/113