Limitations of charge efficiency in capacitive deionization processes III: The behavior of surface oxidized activated carbon electrodes

Eran Avraham, Malachi Noked, Yaniv Bouhadana, Abraham Soffer, Doron Aurbach

Research output: Contribution to journalArticlepeer-review

104 Scopus citations

Abstract

In previous papers we reported on attempts to improve the performance of water desalination using capacitive de-ionization (CDI) processes by understanding the ions transport and adsorption/desorption behavior of activated carbon electrodes as a function of the applied potential. We also investigated the charge efficiency in CDI processes of brackish water in symmetrical cells containing identical highly porous activated carbon electrodes. In this work, we study the influence of oxygen-containing surface groups on activated carbon electrodes on the adsorption/desorption behavior of ions in brackish water. A special methodology was developed in order to estimate the charge efficiency of CDI processes which include the ability to prepare various kinds of activated carbon electrodes (ACEs) with controlled porosity and surface groups, measuring the PZC (potential of zero charge) of ACE in solutions and simultaneous adsorption and desorption of ions into/from them. The presence of polar, oxygen containing surface groups on ACE does not affect the electroadsorption behavior of Na+ and Cl- ions into porous carbons whose average pore size is greater than 0.58 nm, apart of considerably changing the PZC. This results in a shift of the entire curves of ion adsorption vs. potential. The possible use of ACE with oxidized surfaces in CDI processes is discussed.

Original languageEnglish
Pages (from-to)441-447
Number of pages7
JournalElectrochimica Acta
Volume56
Issue number1
DOIs
StatePublished - 2010

Keywords

  • Activated carbon electrodes
  • Capacitive deionization (CDI)
  • Electro-adsorption
  • Surface groups
  • Water desalination

Fingerprint

Dive into the research topics of 'Limitations of charge efficiency in capacitive deionization processes III: The behavior of surface oxidized activated carbon electrodes'. Together they form a unique fingerprint.

Cite this