Electrochemical behavior and complexation of thallous chloride in aqueous solutions: Insights from cyclic voltammetry with bromocresol green

This study investigates the solvation and electrochemical behavior of thallous chloride (TlCl) in aqueous KNO₃ solutions, both in the presence and absence of bromocresol green (BCG). Cyclic voltammetry was employed to evaluate the thermodynamic, diffusion, and kinetic parameters at varying scan rates and concentrations of Tl and BCG. The main reduction peak for TlCl was observed at −1.0 V, while the oxidation of thallous ions occurred at −0.6 V. An increase in thallous concentration led to enhanced solvation and diffusion parameters. The addition of BCG resulted in a significant decrease in the redox waves of thallous ions, indicating a complexation reaction that could be applied to reduce thallous ions toxicity. The research also emphasizes the thermodynamic parameters, stability constants, and Gibbs free energies associated with complexation, all of which decreased as ligand concentration increased. The findings demonstrate that the presence of bromocresol green significantly influences the electrochemical behavior of TlCl in aqueous solution. The observed decrease in redox activity of thallous ions upon the addition of BCG suggests effective complexation, which may serve as a strategy to mitigate the toxicity of Tl ions. The results underscore the importance of understanding solvation dynamics and the role of ligands in modifying the electrochemical properties of toxic metal ions. Future work should focus on further elucidating the mechanisms of complexation and exploring potential applications in environmental remediation.