Enhanced Salt Removal in an Inverted Capacitive Deionization Cell Using Amine Modified Microporous Carbon Cathodes

Xin Gao, Ayokunle Omosebi, James Landon, Kunlei Liu

Research output: Contribution to journalArticlepeer-review

171 Scopus citations

Abstract

Microporous SpectraCarb carbon cloth was treated using nitric acid to enhance negative surface charges of COO- in a neutral solution. This acid-treated carbon was further modified by ethylenediamine to attach -NH2 surface functional groups, resulting in positive surface charges of -NH3+ via pronation in a neutral solution. Through multiple characterizations, in comparison to pristine SpectraCarb carbon, amine-treated SpectraCarb carbon displays a decreased potential of zero charge but an increased point of zero charge, which is opposed to the effect obtained for acid-treated SpectraCarb carbon. An inverted capacitive deionization cell was constructed using amine-treated cathodes and acid-treated anodes, where the cathode is the negatively polarized electrode and the anode is the positively polarized electrode. Constant-voltage switching operation using NaCl solution showed that the salt removal capacity was approximately 5.3 mg g-1 at a maximum working voltage of 1.1/0 V, which is an expansion in both the salt capacity and potential window from previous i-CDI results demonstrated for carbon xerogel materials. This improved performance is accounted for by the enlarged cathodic working voltage window through ethylenediamine-derived functional groups, and the enhanced microporosity of the SpectraCarb electrodes for salt adsorption. These results expand the use of i-CDI for efficient desalination applications.

Original languageEnglish
Pages (from-to)10920-10926
Number of pages7
JournalEnvironmental Science and Technology
Volume49
Issue number18
DOIs
StatePublished - Sep 15 2015

Bibliographical note

Publisher Copyright:
© 2015 American Chemical Society.

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry

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