Chapter

Chemical Oxidation

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Abstract

Chemical oxidation is a process involving the transfer of electrons from an oxidizing reagent to the chemical species being oxidized. In water and wastewater engineering, chemical oxidation serves the purpose of converting putrescible pollutant substances to innocuous or stabilized products. Chemical oxidation processes take place in natural waters and serve as an important mechanism in the natural self-purification of surface waters. Oxidative removal of dissolved iron and sulfide pollutants in aerated waters is a prominent example. The degradation of organic waste materials represents an even more important phenomenon associated with natural water self-purification. It is well known that the efficacy of natural water organic oxidations is due to the presence of microorganisms, which serve to catalyze a highly effective utilization of dissolved oxygen as an oxidant. In fact, such microorganism-catalyzed processes have been optimized and developed into the various forms of so-called “biological processes” in high concentration organic waste treatment applications. The subject of biochemical oxidation processes is thus covered in a different book that deals with biological treatment processes.

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Catalytic oxidation of phenol in aqueous solution over supported copper oxide was studied in the batchwise mode at atmospheric and above-atmospheric pressure and between 369 and 419°K. The reaction undergoes an induction period and transition to a much higher, steady-state activity regime. The reaction is first order with respect to phenol in both regimes, but the oxygen dependency decreases from first to one-half order in shifting from the induction period to the steady-state activity regime. The rate shows other than first-order behavior with respect to catalyst loading. The reaction is proposed to involve a free-radical mechanism. Oxidation rates at atmospheric pressure conditions are too slow to be of practical interest but can easily be brought into the range of practical importance by only moderate increases in temperature and operating pressure.
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