Selective Ammonium Removal from Synthetic Wastewater by Flow-Electrode Capacitive Deionization Using a Novel K2Ti2O5-Activated Carbon Mixture Electrode

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

3 Scopus Citations
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Author(s)

  • Lin Lin
  • Jiahui Hu
  • Xin He
  • Bing Li
  • Xiao-yan Li

Detail(s)

Original languageEnglish
Pages (from-to)12723-12731
Number of pages9
Journal / PublicationEnvironmental Science and Technology
Volume54
Issue number19
Online published14 Sep 2020
Publication statusPublished - 6 Oct 2020
Externally publishedYes

Abstract

Ammonium (NH4+) in wastewater is both a major pollutant and a valuable resource. Flow-electrode capacitive deionization (FCDI) is a promising technology for chemical-free and environmentally friendly NH4+ removal and recovery from wastewater. However, the coexisting sodium (Na+) in wastewater, with a similar hydrated radius to NH4+, competes for the adsorption sites, resulting in low NH4+ removal efficiency. Here, potassium dititanate (K2Ti2O5 or KTO) particles prepared by the electrospray method followed by calcination were mixed with activated carbon (AC) powder to form a novel KTO-AC flow-electrode for selective NH4+ removal over Na+. The mixed KTO-AC electrode exhibits a much higher specific gravimetric capacitance in NH4Cl solution than in NaCl solution. Compared with the pure AC electrode in the FCDI tests on NH4+ removal from synthetic wastewater, 25 wt % KTO addition in the electrode mixture increases the adsorption selectivity from 2.3 to 31 toward NH4+ over Na+, improves the NH4+ removal from 28.5% to 64.8% and increases the NH4+ desorption efficiency from 35.6% to over 80%, achieving selective NH4+ recovery and effective electrode regeneration. Based on DFT calculations, NH4+ adsorption on the K2Ti2O5 (0 0 1) surface is more thermodynamically favorable than that of Na+, which contributes to the high NH4+ adsorption selectivity observed.

Citation Format(s)

Selective Ammonium Removal from Synthetic Wastewater by Flow-Electrode Capacitive Deionization Using a Novel K2Ti2O5-Activated Carbon Mixture Electrode. / Lin, Lin; Hu, Jiahui; Liu, Jiahua; He, Xin; Li, Bing; Li, Xiao-yan.

In: Environmental Science and Technology, Vol. 54, No. 19, 06.10.2020, p. 12723-12731.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review