Oxidation of Ce(III) to Ce(IV) by Ozone in Nitric Acid Medium Using a Static Mixer: Mathematical Modeling and Experimental Validation

This paper deals with a cerium based redox chemical process which is employed to remove fixed radioactive contaminants from alpha bearing metallic surfaces, worldwide. Oxidation of cerium to its fourth valence state is a crucial step of this process. We present an inactive bench scale study to obtain the effect of various process parameters on conversion of Ce(III) to Ce(IV) by ozone in nitric acid medium, using an SMX type of static mixer. Two different mathematical models, one considering a simple semibatch mixed reactor configuration and another based on the concept of axial dispersion, were developed for predicting Ce(III) conversions using the said static mixer, in a full recycle mode. Simulation results from the models matched fairly well to experimental data, with respective mean absolute percentage deviations of 21.1% and 17.4%, computed over all the parameters. An attempt to extend these models for other non-nuclear environmental applications is also described.