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IMPROVED TECHNIQUES FOR RESIDUAL OZONE
Citation:
Gordon, G. AND J. Grunwell. IMPROVED TECHNIQUES FOR RESIDUAL OZONE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-84/036.
Description:
Eight analytical methods for the determination of residual ozone in water are evaluated. Four are iodometric methods based on the reduction of ozone by iodide ion: the iodometric method, the amperometric method, the arsenic (III) back titration method, and the N, N-diethyl-p-phenylenediamine (DPD) method. Four are non-iodometric methods: the indigo method, the arsenic (III) direct oxidation method, the Delta electrode, and the direct measurement of ultraviolet absorption at 259 nm. Two or more analytical methods are compared by simultaneous measurement of the decay curve of ozone in water. This kinetic technique allows a direct comparison of methods under conditions of rapidly changing ozone concentration. The mechanism of ozone decay is discussed. Four exploratory methods based on new ozone-reductant reactions are discussed: the chlorite ion method, the iodate method, the iron (II) terpyridine method, and the cerium method. The failure of these potential new methods is traced.