Assessment of Captan Pesticide Stability by Thermal and Spectroelectrochemical Analysis

In this study, thermal analysis and electrochemical methods were used to evaluate the stability of captan pesticide (CPTN). Simultaneous Thermogravimetry (TG), Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC) were successfully applied to study the stability of CPTN in the temperature range from 20 to 600 °C. The stability evaluation of CPTN by spectroelectrochemical analysis was carried out using cyclic voltammetry (CV) and electrolysis at constant current density in association with UV−Vis spectrophotometry. Thermoanalytical results revealed a relative stability of CPTN up to a temperature of 154 °C, and above this temperature the pesticide molecule undergoes irreversible degradation. The kinetic approach of the electrochemical results on the electrochemical degradation of CPTN showed a rate constant of 0.02min−1 in the presence of chloride ions and 0.089min−1 in the presence of bromide ions. Thermal and electrochemical methods are considered effective strategies applied in order to eliminate pesticides from polluted waters, and the choice of optimal parameters can considerably increase the efficiency of decontamination. The study also aims to provide insights into electrode processes to address the mechanism of electrochemical degradation.