Degradation of potassium diclofenac using ozone: Evaluation of the central compound rotational design and kinetics

Abstract

This work aims to use the ozonation process for the degradation of the drug diclofenac potassium (DK), using a rotational design of 2² central compounds, varying the DK concentration from 5.9 to 34.1 (mg L⁻¹) and O₃ mass flow rate from 292.9 to 1707.1 (mg h⁻¹) to verify its degradation kinetics in the ideal condition by the first (FO) and second order (SO) models and theoretically evaluate the degradation mechanism of the DK molecule by verifying the possible intermediates formed in the process. A 68.97 % degradation of DK was observed after 30 minutes of reaction, the best model was PSO with R² of 0.952 with k₂ of 0.009 (L (mg min)⁻¹) indicating strong interaction of the reagents (DK+O₃) for the degradation mechanism, the formation of HClO and KClO₃ was noted in the medium. Finally, the degradation of DK with O₃ proved to be effective, enabling the use of this effluent/waste in the formation of commercial products with added value, as in the case of KClO₃, thus being an environmentally friendly means of promoting the circular economy without harming the environment by forming more waste.