Development of a Digestion Procedure for MnO₂ Particles by Fe²⁺ in Preparation for Electrochemical Detection in Drinking Water

Authors

Kayla Elliott, Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, ON K7L 3N6;Beaty Water Research Centre, Queen’s University, 69 Union St., Kingston, ON K7L 3N6.
Sarah Jane Payne, Department of Civil Engineering, Queen’s University, 58 University Ave., Kingston, ON K7L 3N6; Beaty Water Research Centre, Queen’s University, 69 Union St., Kingston, ON K7L 3N6.Follow
Zhe She, Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, ON K7L 3N6;Beaty Water Research Centre, Queen’s University, 69 Union St., Kingston, ON K7L 3N6.Follow

Document Type

Article

Corresponding Author(s)

Sarah Jane Payne(sarahjane.payne@queensu.ca);
Zhe She(zhe.she@queensu.ca)

Abstract

Developing detection methods for contaminants in drinking water is essential to ensuring that safe and acceptable quality drinking water is delivered to consumers. While manganese (Mn) was previously known only as a mere aesthetic issue, recent epidemiological data has shown to have negative neurological effects on humans, especially on children, prompting new health-based guidelines by Health Canada and the World Health Organization (WHO). In drinking water, Mn exists predominantly as Mn(II) and Mn(IV) and is regulated based on total Mn levels. Interestingly, measurement of Mn particulate using electroanalytical methods has not yet been reported in the literature. Herein, a digestion procedure for insoluble MnO₂ using Fe²⁺ ions was optimized in preparation for Mn detection using cyclic voltammetry (CV). Digestion conditions including Fe²⁺ ion concentration, pH and digestion time were explored and optimized. Digestion of MnO₂ was found to be successful in both perfect and imperfect stoichiometric ratios; however, digestion was shown to be most effective in perfect stoichiometric conditions. CV proved to be an effective technique for the detection of different particulate Mn concentrations with good reproducibility using glassy carbon electrodes. After 4.5 hrs of digestion, CV obtained a detection limit of 0.3 mM, while after 24 hrs of digestion, CV obtained a detection limit of 0.1 mM for MnO₂. The digestion method, in addition to CV detection was found to be impacted by the presence of Cu²⁺ and Fe³⁺ ons.This interference suggests that this method may offer value as a multi-plexed technique. The Mn reduction signal was found to be enhanced by the presence of Mn²⁺, indicating that this method has the potential to be used to detect soluble and insoluble Mn species simultaneously. These digestion and detection methods are simple and reproducible methods which introduce the opportunity for total Mn detection in drinking water.

Graphical Abstract

Keywords

Manganese, Drinking Water, Cyclic Voltammetry, Digestion, Manganese Dioxide

DOI

10.61558/2993-074X.3572

Online Date

7-4-2025

Recommended Citation

Kayla Elliott, Sarah Jane Payne, Zhe She. Development of a Digestion Procedure for MnO₂ Particles by Fe²⁺ in Preparation for Electrochemical Detection in Drinking Water[J]. Journal of Electrochemistry, doi: 10.61558/2993-074X.3572.