Iron sorption cesium

For each nuclide studied, the sorption distribution coefficients appeared to result from a minimum of two separate mechanisms. In all cases, one mechanism appears to be an ion-exchange phenomena associated with the silicate phases and appears to have a relatively much larger sorption capacity than the other mechanism. In the case of cesium (and probably rubidium) the second mechanism appears to also be related to the silicate phases and may or may not be an ion-exchange phenomena. However, for the other elements studied, the second mechanism appears to be related to the hydrous iron and manganese oxides and again may or may not be an ion-exchange process. 

Another phyllosilicate mineral, namely, biotite, has larger sorption capability as expected. It is likely related to the iron content of biotite. Similarly, the carbonates containing iron and magnesium (ankerite and dolomite Table 3.8) show more significant cesium sorption as calcite (calcium carbonate), which practically does not adsorb cesium. The low sorption ability of calcite can be explained by the Hahn adsorption rule (Chapter 1, Section 1.2.4) that is, the sorption is low when the sorbate (cesium carbonate) has great solubility. 

The construction and application work on the linear model of sorption has important results. First, the distribution coefficients of the different minerals for radioactive ions in very low concentrations can be determined. The minerals with similar structure obviously have similar distribution coefficients because of the similar sorption mechanism. The differences are the results of a specific property of the minerals for example, the presence of iron of magnesium in carbonates has a significant effect on the sorption of the cesium ion. 

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