Sorption uranium isotherms

Figure 1. Cesium and Uranium Isotherms for Sorption on Sandstone at 23(o), 60(D), and 85°C(A). Oxidizing Conditions Were Used for Cesium and Reducing Conditions for Uranium.

Sorption isotherms were also measured for sorption of selenium, technetium, tin, radium, uranium, neptunium, plutonium, and americium on the reference Mabton Interbed solids. The GR-1A groundwater composition was used in these experiments. Two temperatures (23°C 2°C and 60°C 1°C) were used, and both oxidizing and reducing conditions were used for each radionuclide. 

Tin and americium were so extensively sorbed under all conditions that isotherm data could not be obtained. These elements are not significantly mobile in the Mabton Interbed aquifer. Values of Freundlich constants for technetium, radium, uranium, neptunium, and plutonium are given in Table IV. The Freundlich equation did not fit the selenium sorption data very well probably because of slow sorption kinetics or precipitation. Precipitation was also observed for technetium at 23°C for concentrations above 10 7M. This is about the same solubility observed for technetium in the sandstone isotherm measurements. Linear isotherms were observed only in the case of radium sorption. In general, sorption on the Mabton Interbed was greater than on the Rattlesnake Ridge sandstone. This is probably due to the greater clay content of the Mabton standard. 

Figure 3. Sorption and Desorption Isotherms for Uranium Sorption on Mabton Interbed Solids, (a) Oxidizing Conditions, (b) Reducing Conditions.

Gonzalez-Luque and Streat [45] determined the isotherms for the sorption and desorption of uranium from synthetic phosphoric acid solutions in the presence of interfering cations, such as Fe(II) and Ca(II), with these different impregnated resins and one commercial aminophosphinic acid ion-exchange resin. The effect of phosphoric concentration on uranium... 

The surface complex formation constants and the protolysis constants were optimized by using the experimentally obtained data sets and the computer code FITEQL (Herbelin and Westall, 1996). Surface site densities were evaluated from adsorption isotherms at pH 6.5 and a total uranium concentration of 1x10" M. The formation of ferrihydrite during the batch sorption experiment was identified by Mossbauer spec-... 

Fig. 2. Isotherm data for radium, uranium(VI) and plutonium sorption onto haematite (using the batch-sorption technique, liquid solid ratio indicated on diagrams). The general form of the data is consistent with a linear sorption mechanism. For information, error bars corresponding to 40% of the measured value are shovra (see text for further discussion of experimental variability).

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