Ozone and chlorine dioxide: Similar chemistry and measurement issues |
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Authors: | Gilbert Gordon Bernard Bubnis |
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Affiliation: | Department of Chemistry and Biochemistry , Miami University , Oxford, Ohio, USA |
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Abstract: | The chemical reactions associated with ozone and chlorine dioxide can be complicated and involve numerous intermediates. When ozone is applied, the presence of reactive intermediate species (O2 ‐, O3 ‐, OH, HO2, HO2 ‐, and H2O2) influence the extent of oxidation that takes place and determines the amount and types of by‐products formed. Similarly, when chlorine dioxide is applied the amount of intermediate (Cl2O2) formed determines whether chlorine dioxide producing reactions or chlorate ion forming reactions occur. Ozone and chlorine dioxide are excellent agents for inactivating Cryptosporidium and Giardia. Microbiologically, each of the agents are very reactive. In the case of ozone, typically each molecule undergoes a one‐electron change. The mechanism of chlorine dioxide inactivation involves a recycling process whereby chlorine dioxide is reduced to chlorite ion followed by the “regeneration” of chlorine dioxide that continues to react within the cell over and over again. Chlorite ion also has oxidizing power and in some cases, is a biocide. When ozone and chlorine dioxide are used in combination, it is important that the chlorine dioxide application follow the ozone treatment to prevent the formation of unwanted by‐products such as ClO3 ‐. |
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Keywords: | Ozone Chlorine Dioxide Chlorine Dioxide Generation Bromate Ion Generation Oxidant demand Analytical Methods Gas Diffusion Indigotrisulfonate IDBP(Inorganic Disinfection By‐Products) |
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