Development of an Enhanced Ozone-hydrogen Peroxide Advanced Oxidation Process

Abstract

Advanced chemical oxidation processes (AOP’s), particularly processes using.ozone, involve a rapidly growing area of environmental research and applications. A need exists, however, for improvements to AOP’s to make them less costly and more effective. This paper evaluated the addition of a fixed bed of sand to the conventional H₂O₂-O₃ process as a function of reactor configuration, pH, and sand type. The West Liberty sand consisting of the greatest concentrations of iron and manganese yielded the best results, showing 15% more phenol removal than Muscatine sand and 28% more removal than no sand (i.e. H₂O₂-O₃). Phenol degradation product formation and disappearance rates in comparison to the direct ozonation and O₃-H₂O₂ processes indicate metal-oxide sand surface-catalyzed H₂O₂ decomposition improves the conventional O3-H2O2 advanced oxidation process at pH 7. Analysis of results suggests the enhancement is a result of increased formation of essential oxygen radical intermediates (i.e. hydroxyl radical). Direct ozonation, however, was equally effective at phenol removal at pH 8.9 because the conjugate base of phenol (i.e. phenate ion) has a direct ozonation reaction rate constant six orders of magnitude greater than phenol.