Synergistic effects between different advanced oxidative treatments for degradation of Rhodamine B

Advanced oxidative processes (AOPs) have been extensively investigated for the removal of a wide range of organic contaminants, including dyes, pharmaceuticals, and other industrial pollutants. However, systematic evaluations of synergistic effects among different AOP configurations remain limited. This study investigated the synergistic interactions between AOPs for the degradation and mineralization of Rhodamine B, a dye widely used as a model compound for industrial effluents. Solutions were treated using photolysis (UV), hydrogen peroxide (H₂O₂), UV/H₂O₂, Fenton (Fe²⁺/H₂O₂), and photo-Fenton (Fe²⁺/H₂O₂/UV) processes. H₂O₂ concentrations ranged from 1.6 to 43.2 mmol/L when applied alone and from 0.53 to 4.8 mmol/L in Fenton and photo-Fenton systems, using Fe²⁺/H₂O₂ ratios of 1:5 and 1:10. The results revealed that the UV/H₂O₂ achieved 69% degradation within 2 h at 14.4 mmol/L of H₂O₂, outperforming the individual treatments. The photo-Fenton process exhibited superior efficiency, achieving complete degradation in half the time required by the Fenton process at 0.5 mmol/L of H₂O₂ and an Fe²⁺/H₂O₂ ratio of 1:5. Furthermore, mineralization increased by 20% when UV was incorporated. This study demonstrates that integrating AOPs enhances the performance, supporting the optimization of the treatments for dye-containing wastewaters and reinforcing the importance of synergistic strategies for environmental remediation.