Didactic experiment for voltametric determination the complexing capacity of natural waters
1 Department of Chemistry, Federal University of Viçosa, 36.570-900 - Viçosa, Brazil.
2 Dinamic Faculty of Piranga Valley, 35.430-302 - Ponte Nova, Brazil.
3 College of Application of the Federal University of Viçosa, 36.570-900 - Viçosa, Brazil.
Research Article
World Journal of Advanced Engineering Technology and Sciences, 2024, 11(01), 337–344.
Article DOI: 10.30574/wjaets.2024.11.1.0069
Publication history:
Received on 13 January 2024; revised on 24 February 2024; accepted on 26 February 2024
Abstract:
The titration method can be applied to determine the complexation capacity between metal ions and ligands in natural water samples. The process involves the incremental addition of the metal to the sample containing a specific ligand, resulting in a titration curve that reflects the formation of complexes. The change in the curves slope indicates the saturation of the complexation capacity. In this study, the copper (II) ion was used due to its stability with organic ligands. The titration curve was analyzed to determine the complexation capacity (CC) and conditional formation constant (K) of the complex. Different mathematical treatments are proposed for this analysis. In the described experiment, differential pulse anodic stripping voltammetry was used to determine the complexation capacity of humic substances in natural waters. Experimental parameters such as pH, supporting electrolyte concentration, and volume of additions were previously optimized for the voltammetry technique. The obtained data were processed and analyzed, resulting in titration curves and voltammograms. The analysis of the curves allowed for the calculation of the complexation capacity and conditional stability constant of the formed complex. The results demonstrate the feasibility of the method as a didactic experiment for the voltammetric determination of natural water complexation capacity.
Keywords:
Natural Waters; Voltammetry; Complexation Capacity; Formation Constant
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