The fraction of mobile Pu species for filtration of Pu solutions throu
gh silicate rock depends on the preparation method, the pH, the thickn
ess of the filtering layer, and the solution composition. The fraction
of mobile Pu species is 2-20% for filtration of solutions containing
2.3 . 10(-8)-8.6 . 10(-7) M Pu and 0.05 M NH4NO3 through a layer of qu
artz sand 4.5 cm in height with an average grain size of 310-290 mu m.
The minimal values are observed for solutions in which hydrolysis and
polymerization of Pu hydroxy complexes are most extensive. Plutonium
is weakly retained by a layer of quartz sand from solutions containing
humic substances. This is due to the binding of Pu to finely disperse
d colloidal soil particles that pass through the quartz sand with an a
verage grain size of 310-290 pm. Washing the layer of quartz sand cont
aining Pu with various solutions at pH 6-7.7 does not substantially mo
bilize the Pu.