In solution, they are easily regenerated as hydroxides by the addition of calcium (or strontium or barium) hydroxides for reuse, since the carbonates of these three elements are all insoluble.
Evaporated they may also be decomposed by heat.
Cesium, and to a lesser extent, rubidium and potassium, on heating of the carbonates can generate (with appropriate separation schemes) the free metals and equimolar mixtures of oxygen and carbon dioxide gas, an excellent tool for reformation reactions.
Radioactive cesium is of particular interest for side products containing halogen containing contaminants which may appear in the combustion of municipal wastes, and will quantitatively destroy the most problematic of all nitrogen oxides - the most persistent - nitrous oxide, N2O. (In fact, N2O gas can be utilized as a radiological dosimeter.)
It is also self heating.
In an ideal world, the radiocesium available - regrettably there isn't that much - might be utilized to make the insoluble compound cesium titanate, possibly nanostructured to include some barium fluoride. This material - which has been evaluated as a "waste form" for disposal, disposal being a very bad idea in my view - has the interesting property when irradiated of producing electron holes that can decompose some otherwise intractable halides. Exposed to air, it would remove N2O, SF6, residual CFC's, HFC's with air flow being maintained with convective heat from the radioactive decay.
If located in cities, this would destroy the important ground level pollutant ozone, by generating the same chemistry as been worrisome in the upper atmosphere where the radiation source is high energy solar radiation, gamma, x-rays and UV. Of course, in the upper atmosphere, ozone is an important shielding agent, but at the ground level, it is a serious pollutant, responsible for a fair share of the unacceptably large death toll from air pollution.
Exposed to water it could remove contaminants like the horrible PCB problem that has plagued the Hudson River, among other places, and I believe some of the serious perfluoroalkanoic acids, the most prominent such molecule being PFOS, perfluorooctanoic acid.
If one looks at old literature from the 1950's and 1960's, one can realize that many scientists then recognized the potential of fission products to be utilized for a number of very interesting applications. Regrettably, probably as a result of open air nuclear testing, these scientists ideas were lost owing to mass hysteria of the type that continues to plague the planet in an extremely destructive way.
There are no fission products, none, that cannot be put to use. I have spent 30 years convincing myself of that. They are wonderful and remarkable materials, many of which can do things that other radiologically stable materials cannot.
Regrettably, stupidity prevents us from recognizing this, in part because our culture has a "waste mentality" that believes in dumps. Of course the worst dump is our planetary atmosphere, and its use as such is killing us. We could shut this dump, and in fact clean it up and remediate it by embracing nuclear materials, but again, as a culture, we are too stupid to do so.
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