Water exchange uranyl complexes

U Anion-exchange uranyl thio-cyanide complex Water (0.04 Mg/1) 328)... 

Differences in behavior of actinides in the aquatic environment are shown by the data in Table VI. In WOL, we have noted that about 12% of the total Pu in the water column passes a 0.45-vim filter and also passes a 10,000 mol wt membrane filter. Essentially all of this soluble Pu is retained when passed through an anion exchange column. Curium-244 behaves somewhat differently in that about 50% of the activity in WOL water is soluble, but it also behaves anionically. The reasons for a negative charge on Pu and Cm are complex and are not understood, but one possible explanation is the presence of Pu(VI) carbonate complexes, analogous to the soluble uranyl carbonate complexes found in natural waters. Experiments are in progress to determine the valence state of this soluble form of Pu. Another explanation for the observed soluble Pu would be organic complexes. 

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