Oxidation of organic matter for chemical oxygen demand determination

Oxidation of organic matter for chemical oxygen demand determination 

Since degradation of organic matter requires the presence of oxygen, the content of organic matter in a given aqueous system can be estimated from the amount of oxygen 

As in other oxidation processes, increased temperatures have an adverse effect which aiso ascribed to the resuiting increased vapour pressure ieading to easier cavitation, but iess vioient coiiapse, as a consequence of the decreased viscosity and surface tension. As the temperature approaches the soivent boiiing point, a iarge number of cavitation bubbies are formed concurrentiy that act as a barrier to sound transmission and dampen the effective US energy from the source to enter the iiquid medium. A temperature dose to room ievei is easy to maintain and ensures proper deveiopment of the process. 

Bubbiing a gas through an oxidizing medium subjected to US had a favourabie effect on the process no differences, however, were observed in the use of monoatomic (e.g. Kr, Ar, He) or diatomic gases e.g. N2, O2, air), or in the manner the gas was bubbied (before or during sonication). 

Concerning interferences with the oxidation of organic matter in water, US-assisted oxidation toierates the presence of chioride ions up to 7000 mg/i for 100 mg/i COD as 

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