Fluorescent sensing and determination of mercury (II) ions in water

Authors

  • Phendukani Ncube Department of Applied Chemistry, University of Johannesburg, PO Box 17011, Doornfontein 2028, South Africa
  • Rui WM Krause Department of Applied Chemistry, University of Johannesburg, PO Box 17011, Doornfontein 2028, South Africa
  • Derek T Ndinteh Department of Applied Chemistry, University of Johannesburg, PO Box 17011, Doornfontein 2028, South Africa
  • Bhekie B Mamba Department of Applied Chemistry, University of Johannesburg, PO Box 17011, Doornfontein 2028, South Africa

DOI:

https://doi.org/10.4314/wsa.v40i1.21

Keywords:

azo dye, crown ether, fluorescence, mercury (II), sensor, water

Abstract

The presence of heavy metals released from industrial activities into water streams is an ever-growing challenge to ensuring a safe and clean aquatic environment. Detection and determination of the levels of these heavy metals in wastewater is an important step before any measures can be taken. In this study we report on a fluorescent sensing probe based on a naphthyl azo dye modified dibenzo-18-crown-6-ether (DB18C6) for the detection and determination of mercury (II) ions in water. The probe showed high sensitivity and selectivity towards the mercury (II) ion among various alkali, alkaline earth, and transition metal ions. The mercury (II) ion quenched the fluorescence of the probe. Stern-Volmer quenching constants (Ksv) were found to be highest for Hg2+ ion at 1.18 x 105 M-1 compared to 3.85 x 104 M-1 for copper (II) ion. The stoichiometry of the sensor–metal ion interaction was found to be 1:1 for both metal ions using Job plots. The detection limit for Hg2+ was 1.25 x 10-8 M. The dye modified crown ether was then used to detect mercury in a water sample from a coal-fired power plant and to determine the amount of mercury in the water sample.

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Published

2025-03-31

Issue

Vol. 40 No. 1 January (2014): Water SA

Section

Research paper

License

Copyright (c) 2025 Phendukani Ncube, Rui WM Krause, Derek T Ndinteh, Bhekie B Mamba

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Creative Commons License

The content of this journal is licensed under a Creative Commons Attribution Licence.  Users are permitted to read, download, copy, distribute, print, search or link to the full texts of the articles in this journal under the terms of this Licence, without asking prior permission from the publisher or the author, provided the source is attributed. Copyright is retained by the authors.

How to Cite

Phendukani Ncube (2025) “Fluorescent sensing and determination of mercury (II) ions in water”, Water SA, 40(1 January). doi:10.4314/wsa.v40i1.21.