Removal of acid yellow 36 using Box–Behnken designed photoelectro-Fenton: a study on removal mechanisms

Abstract

Photoelectro-Fenton was applied for the removal of acid yellow 36 (AY36) from synthetic aqueous solution using iron electrodes. A Box–Behnken design was used for optimization of the effects of pH, H₂O₂ concentration, current density, and reaction time. Individual effects of these variables were more important than their interaction effects. The derived model was in good agreement with the experimental results. Total organic carbon was determined in solution and sludge in order to clarify the removal mechanism. Increase of H₂O₂ concentration and current density led to domination of oxidation and coagulation mechanisms, respectively. The effects of scavenging and inhibiting agents were also investigated: (1) presence of alcohols can reduce the efficiency through competition with dye for reaction with hydroxyl radicals; (2) anions (NO₃⁻, HCO₃⁻, and H₂PO₄⁻) scavenged hydroxyl radicals and reduced decolorization of AY36.

Keywords:

• photoelectro-Fenton
• Box–Behnken design
• removal mechanism
• dye

Acknowledgments

The authors would like to thank Mr Jalal Karimpour and Ms Mina Sayyadi for providing the cylindrical quartz reactor. They would also like to thank the anonymous reviewers for their suggestions.

Disclosure statement

The authors declare that there is no conflict of interest.