Mineralization as a mechanism for TOC removal: Study of ozone/ozone-peroxide oxidation using FT-IR

FT-IR spectroscopy was used to study the course of abiotic mineralization in samples treated with ozone and ozone:peroxide. The importance of oxidative mineralization as a mechanism for dissolved organic carbon (DOC) removal during disinfection must be determined if advanced oxidation processes (AOPs) in water and wastewater treatment is to be fully exploited. Understanding the full impact of these applications is critical for determining how effective a remedy AOPs are for eliminating disinfection by-product formation and for assessing how well these applications might facilitate compliance with future regulatory changes. Although these processes have been shown to surpass the level of disinfection afforded by traditional techniques and improve biodegradability, this study found that the use of ozone, or ozone in combination with hydrogen peroxide, to chemically effect TOC reduction may have practical limitations when applied to dilute aqueous solutions containing both refractory and degradable dissolved organic carbons. Reactions possessing very favorable thermodynamics were found, by an indirect measure, to be complicated by solute/solvent interactions which may have served to inhibit oxidation. It was also shown that "close to real time" CO2 plots generated using highly sensitive FT-IR techniques may have some practical utility in assessing mineralization potential and optimizing disinfection processes. (C) 2000 Elsevier Science Ltd. All rights reserved.