Dirty Water Electrolysis in Anion Exchange Membrane Systems
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Date
2021
Authors
Beaudoin, Sarah
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
Electrolysis, also known as water splitting, consists of two half-reactions occurring within an electrolytic cell that make possible the extraction of storable and non-pollutive hydrogen gas. Anion-exchange membrane (AEM) electrolysis, utilizing an anion-selective membrane, shows promise for greater resistance to contaminants, potentially allowing for operation using impure water sources. Research regarding AEM electrolyzer performance and failure during operation in impure water feed will contribute to the development of impurity-tolerant electrolyzers and therefore increase the accessibility and implementation of sustainable hydrogen fuel. Electrochemical measurements were conducted using an electrolyzer test stand hardware powered by a Biologic potentiostat. In addition to current and voltage profiles over time, impedance measurements were conducted to understand conductivity changes within the membrane electrode assembly over time. To study the effects of feed water purity, an H-cell consisting of two liquid compartments of varying impurity on either side of an MEA was used. Monitoring the movement of ions between the anode and the cathode was completed via conductivity and pH probe analysis. Using these methods, I have shown that ion transport of Cl- to the anode is driven by diffusion and not accelerated by an applied potential, while Na+ transport from the anode to cathode is enhanced at low current densities but completely mitigated at high current densities.
Description
1 page.
Keywords
electrolysis, renewable energy, hydrogen, fuel cell