A comprehensive kinetic model for phenol oxidation in seven advanced oxidation processes and considering the effects of halides and carbonate

Huang, Kuan; Zhang, Huichun

doi:10.1016/j.wroa.2021.100129

As one of the most powerful approaches to mechanistically understanding complex chemical reaction systems and performing simulations or predictions, kinetic modeling has been widely used to investigate advanced oxidation processes (AOPs). However, most of the available models are built based on limited systems or reaction mechanisms so they cannot be readily extended to other systems or reaction conditions. To overcome such limitations, this study developed a comprehensive model on phenol oxidation with over 550 reactions, covering the most common reaction mechanisms in nine AOPs—four peroxymonosulfate (PMS), four peroxydisulfate (PDS), and one H2O2 systems—and considering the effects of co-existing anions (chloride, bromide, and carbonate) and product formation. Existing models in the literature were first gathered and revised by correcting inaccurately used reactions and adding other necessary reactions. Extensive model tuning and validation were then conducted by fitting the model against experimental data from both this study and the literature. When investigating the effects of anions, we found that PDS/CuO suffered the least impact, followed by the H2O2/UV and other PDS systems, and finally the PMS systems. Halogenated organic byproducts were mainly observed in the PMS systems in the presence of halides. Most of the 556 reactions were found to be important based on the sensitivity analysis, with some involving anions even among the most important, which explained why these anions can substantially alter some of the reaction systems. With this comprehensive model, a deep understanding and reliable prediction can be made for the oxidation of phenol (and likely other phenolic compounds) in systems containing one or more of the above AOPs.

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