Jump to main content
Jump to site search

Issue 60, 2018, Issue in Progress
Previous Article Next Article

High-capacity and selective ammonium removal from water using sodium cobalt hexacyanoferrate

Author affiliations

Abstract

A new NH4+ adsorbent with high capacity and selectivity, sodium cobalt(II) hexacyanoferrate(II) (NaCoHCF, NayCo(II) [Fe2+(CN)6]x·zH2O), was prepared. The adsorption performance was investigated by varying the mixing ratio of [Fe(CN)6]4− to Co2+ during synthesis, Rmix. The ammonia capacity was found to be proportional to Rmix, indicating that the NH4+ capacity can be increased by increasing the Na+-ion content in NaCoHCF. To conduct a detailed study, we prepared homogeneous nanoparticles by flow synthesis using a micromixer with Rmix = 1.00. Even on the addition of a saline solution (NaCl) with an Na+-ion concentration of 9350 mg L−1, the capacity was maintained: qmax = 4.28 mol kg−1. Using Markham–Benton analysis, the selectivity factor, defined by the ratio of equilibrium constants for NH4+ to that for Na+, was calculated to be α = 96.2, and 4.36 mol kg−1 was found to be the maximum capacity. The high selectivity of NaCoHCF results in good NH4+-adsorption performance, even from seawater. In comparison with other adsorbents under the same conditions and even for a NH4Cl solution, NaCoHCF showed the highest capacity. Moreover, the coexisting Na+ caused no interference with the adsorption of ammonium by NaCoHCF, whereas the other adsorbents adsorbed ammonia only slightly from the saline solution. We also found that the pores for NH4+ adsorption changed their sizes and shapes after adsorption.

Graphical abstract: High-capacity and selective ammonium removal from water using sodium cobalt hexacyanoferrate

Back to tab navigation

Supplementary files

Publication details

The article was received on 05 Sep 2018, accepted on 01 Oct 2018 and first published on 08 Oct 2018


Article type: Paper
DOI: 10.1039/C8RA07421F
RSC Adv., 2018,8, 34573-34581
  • Open access: Creative Commons BY license
  •   Request permissions

    High-capacity and selective ammonium removal from water using sodium cobalt hexacyanoferrate

    Y. Jiang, K. Minami, K. Sakurai, A. Takahashi, D. Parajuli, Z. Lei, Z. Zhang and T. Kawamoto, RSC Adv., 2018, 8, 34573
    DOI: 10.1039/C8RA07421F

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements