Évaluation de l'efficacité du système Fe⁰/Chlore pour la dégradation avancée du colorant organique Basique Jaune 28

Abstract

This work focuses on the study of the degradation of an organic basic dye, Basic Yellow 28 (BY28), in aqueous phase using Fe⁰/Chlorine as an AOP process. The main objective is to investigate the influence of operational parameters in order to achieve optimal degradation efficiency. Experiments were carried out in a batch reactor (V=250 ml) under various conditions. The efficiency of the process was first evaluated by assessing the degradation of BY28 when using either iron or chlorine alone, then the obtained results were confronted to those obtained using Fe0/chlorine. The optimized parameters include temperature (25-55 °C), solution pH (3-9), initial dye concentration (10-50 ppm), and length of zero-valent iron (4.51-21 mm) and chlorine (50-500μM). The degradation kinetics were monitored using UV-Visible spectrophotometry. The obtained results showed that approximately 80% of JB28 was removed after 15 minutes of treatment in the presence of 150 μM chlorine. The degradation efficiency increased with increasing concentrations of chlorine and iron, although overdosing did not further improve the process. The fastest degradation occurred under acidic conditions (pH = 3). Alkalinization of the reaction medium significantly slowed down the degradation. The process was more effective at room temperature, as higher temperatures may interfere with the generation of reactive species. The degradation rate decreased with increasing initial dye concentration. Experiments conducted under nitrogen atmosphere confirmed the role of Fe²⁺ generated by corrosion in acidic medium, and the formation of strong oxidizing species responsible for BY28 degradation, mainly hydroxyl radicals (•OH) and reactive chlorine species.