Technetium sorption granite

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. 

Erdal, B.R. Aguilar, R.D. Bayhurst, B.P. Daniels, W.R. Duffy, C.J. Lawrence, F.O. Maestas, S. Oliver, P.Q. Wolfsberg, K. "Sorption-Desorption Studies on Granite. I. Initial Studies of Strontium, Technetium, Cesium, Barium, Cerium, Europium, Uranium, Plutonium, and Americium", in "Proceedings of the Task 4 Waste Isolation Safety Assessment Program Second Contractor Information Meeting", Vol. II, Report PNL-SA-7352, Battelle Pacific Northwest Laboratory, 1978, pp. 7-67. 

Allard, B., Kipatsi, H. and Torstenfelt, B., "Technetium Reduction and Sorption in Granitic Bedrock", subm. to Radiochem. Radioanal. Lett. 

Table III. Sorption Coefficients for Technetium on Quartz, Granite, and Gabbro under Oxic Conditions...

Studies on the sorption of technetium by various minerals demonstrate that only a few percent of pertechnetate arc sorbed by tuff and basalt and that granite, dolomite, and shale sorbed only small amounts (< ()%). However, minerals containing copper, lead or iron sulphide, c.g. bournonite, galena, and chalcopyrite. sorbed pertechnetate... 

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