Solvation Cyclic voltammetry Parameters for Na2WO4 In NaClO4 , HCl Media and lnteraction with Congo Red Dye

Abstract

The study examined the effects of different concentrations of sodium tungstate (Na₂WO₄) using cyclic voltammetry with a glassy carbon electrode (EGC). In acidic HCl and neutral NaClO₄ media, the cathodic reaction of sodium tungstate was characterized by the transfer of tungstate ions to WO₂. Additionally, the oxidation of WO₂ ions to WO₃ was observed. Cyclic voltammetry parameters for sodium tungstate in the absence and presence of Congo red dye were analyzed in both NaClO₄ and HCl media. The stability constants and Gibbs free energies of complexation were estimated for both media, revealing higher values in NaClO₄ compared to HCl. This suggests that the complexation reaction between Na₂WO₄ and Congo red dye is more favorable in NaClO₄ than in HCl. Furthermore, the kinetic and solvation parameters for the interaction of Na₂WO₄ with Congo red in 0.1 M NaClO₄ were lower than those observed in 0.1 M HCl, attributed to a faster electron transfer rate in the HCl medium.