ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Efficient degradation of Ponceau S Using a Co²⁺/H₂O₂/UV advanced oxidation process: a Box–Behnken design approach

Yasmine Laftani, Baylassane Chatib, Tesnim Dhiss, Saoussan El Mouhri, Redouan Hammal, Mohsine Hachkar, and Abdelghani Boussaoud

Laboratory of Process, Signals, Industrial Systems and Computer Science, Graduate School of Technology, Cadi Ayyad University, Safi, Morocco

E-mail: laftani90yasmine@gmail.com

Received: 13 June 2025  Accepted: 21 August 2025

Abstract:

This study investigates the degradation of Ponceau S (PS), a commonly used azo dye, through the cobalt-catalyzed Co²⁺/H₂O₂/UV advanced oxidation process (AOP). Process optimization was performed using the Box–Behnken design (BBD) under the framework of response surface methodology (RSM). Key operational parameters, namely the Co(II) concentration, the hydrogen peroxide (H₂O₂) dosage, and the PS dye concentration, were evaluated to maximize degradation efficiency, as the chosen response, after one hour of irradiation. The statistical analysis of the experimental data produced a robust predictive model with a high coefficient of determination (R² = 0.9655), confirming the model’s reliability. The model F value of 21.79 indicates that the model is statistically significant, with only a 0.03% probability that such a high F value could result from random noise. Among the tested variables, the initial PS concentration and the H₂O₂ dose were found to have a highly significant impact on the degradation efficiency. In contrast, the Co(II) concentration showed no significant effect whether in its linear, interaction, or quadratic forms. Regarding interaction effects, only the interaction between dye concentration and H₂O₂ dose was significant, and among the quadratic terms, only the H₂O₂ dosage showed a notable influence. Optimal conditions for maximum PS degradation were determined to be 0.03 mM dye concentration, 0.55 mM H₂O₂, and 0.06 mM Co²⁺. These findings underscore the potential of the Co²⁺/H₂O₂/UV system as an effective method for azo dye wastewater treatment, with BBD proving to be a valuable tool for operational optimization.

Keywords: Azo dye degradation; Advanced oxidation process; Wastewater treatment; Box–Behnken design; Statistical modeling; Ponceau S

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04347-3

Chemical Papers 79 (12) 8753–8762 (2025)