Flowing Microreactors for Periodate/H2O2 Advanced Oxidative Process: Synergistic Degradation and Mineralization of Organic Dyes
Abderrahmane Talbi, Slimane Merouani, Aissa Dehane
Abstract
The periodate/hydrogen peroxide (PI/H2O2) system is a recently developed advanced oxidation process (AOP) characterized by its rapid reaction kinetics, making it highly suitable for continuous-flow applications compared to conventional batch systems. Despite its potential, no prior studies have investigated its performance under flowing conditions. This work presents the first application of the PI/H2O2 process in a tubular microreactor, a promising technology for enhancing mass transfer and process efficiency. The degradation of textile dyes (specifically Basic Yellow 28 (BY28)) was systematically evaluated under various operating conditions, including reactant concentrations, flow rates, reactor length, and temperature. The results demonstrated that higher H2O2 flow rates, increased PI dosages, and moderate dye concentrations (25 µM) significantly improved degradation efficiency, achieving complete mineralization at 2 mM PI and H2O2 flow rates of 80–120 µL/s. Conversely, elevated temperatures negatively impacted the process performance. The influence of organic and inorganic constituents was also examined, revealing that surfactants (SDS, Triton X-100, Tween 20, and Tween 80) and organic compounds (sucrose and glucose) acted as strong hydroxyl radical scavengers, substantially inhibiting dye oxidation—particularly at higher concentrations, where nearly complete suppression was observed. Furthermore, the impact of water quality was assessed using different real matrices, including tap water, seawater, river water, and secondary effluents from a municipal wastewater treatment plant (SEWWTP). While tap water exhibited minimal inhibition, river water and SEWWTP significantly reduced process efficiency due to their high organic content competing with reactive oxygen species (ROS). Despite its high salt content, seawater remained a viable medium for dye degradation, suggesting that further optimization could enhance process performance in saline environments. Overall, this study highlights the feasibility of the PI/H2O2 process in continuous-flow microreactors and underscores the importance of considering competing organic and inorganic constituents in real wastewater applications. The findings provide valuable insights for optimizing AOPs in industrial and municipal wastewater treatment systems.