Nonsteady State Methods without Mass Transfer Enhancement

1 Nonsteady State Methods without Mass Transfer Enhancement 

The nonsteady state methods described in this section are all based on no or negligible reactions taking place in the system. If reactions are present, the treatment of the mass balances becomes more complicated since 

Other methods to evaluate the data are then necessary (see Levenspiel, 1972 Levenspiel and Godfrey, 1974). 

The most common approach in the laboratory is to use a batch set-up (with respect to the liquid) where ozone-free (clean) water is gassed with the ozone/air or ozone/oxygen mixture. The change in the liquid ozone concentration over time is measured with an ozone probe or an on-line photometer. The mass balance reduces to  

It is important to note that even in clean water, ozone decay (which can be considered a special ozone reaction ) cannot be prevented at pH 4. In order to achieve a situation where no reactions occur (rL = 0), the ozone mass transfer experiments are mostly conducted 

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