Experimental evaluation of Reactive Yellow 17 degradation using UV light and iron ions activated peroxydisulfate: Efficiency and kinetic model

Abstract

In the present study, the degradation of Reactive Yellow 17 (RY17) azo dye in aqueous solution was performed using UV light and iron ions as activators of peroxydisulfate (S₂O₈²⁻ or PDS). The effect of several parameters affecting the degradation process was studied and the optimum conditions are found to be: [RY17] = 10 mg/L, [Fe²⁺] = 0.05 mM, [S₂O₈²⁻] = 1 mM and the pH = 3. The obtained results showed that the removal degrees of RY17 using different processes such as S₂O₈²⁻/Fe²⁺, S₂O₈²⁻/UV and S₂O₈²⁻/Fe²⁺/UV was 63.3%, 81.0% and 95.4% respectively within 20 min of the degradation. Based on theses removal degrees, the degradation efficiency of the RY17 increases in the order: S₂O₈²⁻/Fe²⁺/UV > S₂O₈²⁻/UV > S₂O₈²⁻/Fe²⁺ > UV > S₂O₈²⁻. The experimental data were analyzed using the first-order, second-order and Behnajady-Modirshahla-Ghanbery (BMG) kinetic models, and the kinetic data were in good agreement with the BMG model. Under the optimal conditions, the comparative study of the RY17 degradation using two salts Na₂S₂O₈ and K₂S₂O₈ showed a strong similarity. The total mineralization was monitored using COD and TOC techniques. The results showed that the peroxydisulfate activated by UV and Fe²⁺/UV system is efficient for the degradation and mineralization of RY17; it could also be an alternative for the treatment of the real wastewater contaminated by azo dyes.