A kinetic and mechanistic examination of micelle’s effect on the peroxydisulphate oxidation of [Co ^II CYDTA] ²⁻ catalyzed by Ag(I)

Abstract

Abstract Oxidative processes involving aminocarboxylate complexes and oxy-anions are intriguing for understanding cellular oxygen transport in biological systems. The proposed research aims to examine the implications of anionic, cationic, and neutral surfactants on the Ag + catalyzed peroxydisulphate (S 2 O 8 2− ) oxidation of [Co II CYDTA] 2− (CYDTA = trans-cyclohexane-1,2 diamine N,N,N′,N′-tetra acetic acid). The kinetics of oxidation in both aquatic and SLS/TX-100/CTAB micellar media are assessed by measuring an increase in absorbance at 538 nm. The impacts of pH, [Ag + ], [S 2 O 8 2− ], [Co II CYDTA 2− ], ionic strength, [Surfactant], and temperature were investigated. The inclusion of supplementary cations and the reaction medium’s ionic strength does not influence the reaction rate, indicating that the reaction occurs through the formation of ion pairs. Anions increased catalysis, suggesting an outer sphere mechanism. The analysis of various concentrations revealed that the reaction under investigation exhibited a first-order dependence on [Co II CYDTA 2− ], [Ag + ], and [S 2 O 8 2− ]. The presence of CTAB micelles facilitated approximately 3.3-fold enhancement in the oxidation rate. TX-100 moderately facilitates the oxidation of [Co II CYDTA] 2− , whereas SLS, an anionic surfactant, diminishes the oxidation rate. As a catalyst, CTAB exhibits the best compatibility with Ag + metal salt. The proposed mechanistic approach is further supported by the computed activation parameters.