Technetium sorption

Figure 4. Sorption and Desorption Isotherms for (a) Selenium and (b) Technetium Sorption on Mabton Interbed Solids under Reducing Conditions.

Table VH shows that hydrazine is the only important variable for technetium sorption on each of the geologic solids. Hydrazine causes technetium to be removed from solution either by sorption or by precipitation of the reduced technetium species. Hydrazine is a powerful reducing agent and should reduce TcO/ to technetium(IV) according to standard half-cell potentials. No Tc02 was observed however, since the technetium passed through...

Table II. Chemical Composition of Solutions used Technetium Sorption Studies Concentration in mg/L in the ...

Table V. Ferrous-Iron-Containing Minerals used in Technetium Sorption Studies...

Table VI. Total Iron, Fe(II) and Sulfur. Concentrations in "Opaques" (Ilmenite, Iron Oxides, and Iron Oxyhydroxides used in Technetium Sorption Studies Concentrations in wt%...

The autoradiographs also show some sorption on the granite obtained from the Eye-Dashwa Lakes pluton (Figure 6). Even though the iron concentration is low, hydrothermal alteration of the granite has resulted in the infilling of the minute fractures in the microcline feldspar with iron oxides, which show technetium sorption, while there is no sorption on the biotite crystals. 

Thus, while fresh, unaltered granite matrix rock has little or no iron in the form of iron oxides, alteration zones around fractures do, and technetium sorption may occur there. It should also be noted that sorption of technetium is limited to specific mineral surfaces. Thus, it appears that the reduction of TcO, to a lower oxidation state occurs at or near the surface of the iron oxide and not in the bulk of the solution, by dissolved ferrous ions. 

Actinide and Technetium Sorption on Iron-Silicate and Dispersed Clay Colloids... 

The objectives of the laboratory studies were (1) to study the behavior of volatile technetium compounds produced by direct fluorination of UO with elemental fluorine (2) to study the technetium sorption characteristics of MgF and (3) to determine the feasibility of repeated regeneration of MgF by desorption of technetium with fluorine. 

Pretreatment conditioning of MgF significantly affects technetium sorption capacity. 

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