In Situ Electrochemical Dilatometry of Phosphate Anion Electrosorption

Daniel Moreno, Yousuf Bootwala, Wan Yu Tsai, Qiang Gao, Fengyu Shen, Nina Balke, Kelsey B. Hatzell, Marta C. Hatzell

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Here we investigate the competitive electrosorption of mono- and divalent phosphate anions through electrochemical desalination- and dilatometry-based experiments. Through in situ dilatometry, we monitor the strain at the electrode surface as anions and cations are electrosorbed. Strain measurements show that the presence of divalent ions promotes a greater than anticipated electrode expansion during cation (Na+) electrosorption. The expansion observed with Na+ equaled the expansion observed with HPO4 2-. Because the ionic radius of Na+ is smaller than that of HPO4 2-, the symmetric expansion suggests that divalent anions do not completely desorb during electrode regeneration, causing the adverse interactions with the cation during co-ion expulsion. This results in a decrease in desalination performance, indicated by a decreased salt adsorption capacity. Conversely, an expected asymmetric expansion during anion and cation electrosorption occurs with monovalent phosphate anions (H2PO4 -), indicating that monovalent ions can be effectively replaced by the cation at the electrode surface.

Original languageEnglish (US)
Pages (from-to)745-749
Number of pages5
JournalEnvironmental Science and Technology Letters
Volume5
Issue number12
DOIs
StatePublished - Dec 11 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Ecology
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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