https://doi.org/10.15255/KUI.2022.061
Published: Kem. Ind. 72 (5-6) (2023) 289–295
Paper reference number: KUI-61/2022
Paper type: Original scientific paper
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Determination of Cu2+ Ions Concentration by Electrochemical Methods

S. Gudić and N. Krišto

Abstract

The possibility of determining the concentration of heavy metal ions, i.e., Cu²⁺ ions in an aqueous solution of CuSO₄ ∙ 5H₂O, was tested by electrochemical means. For this purpose, polarisation curves were recorded on a Pt electrode in solutions of known (0.1, 0.5, 1.0, 2.5, 5.0, 7.5, 10.0, 50.0, and 100.0 mM) and unknown concentrations of Cu²⁺ ions with the reading of the limiting diffusion current. Polarisation measurements were performed in the potential range from open circuit potential to −3.0 V with different potential scan rates (1, 5, 10, 20, and 50 mV s^–1). By cathodic deposition on the Pt surface, a reddish-brown copper coating was deposited, the thickness of which increased as the concentration of Cu²⁺ ions in the solution increased. Furthermore, the limiting diffusion current i_d increased linearly with the increase in Cu²⁺ ion concentration, c. The i_d = f(c) plot was constructed and the unknown concentrations of Cu²⁺ ions in three randomly prepared CuSO₄ ∙ 5H₂O solutions were determined. Heavy metal ions from polluted waters (Cu²⁺ ions) can be successfully removed by electrochemical means, and their concentration determined.

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Keywords

heavy metal ions, copper, polarisation measurements, electrodeposition, limiting diffusion current