Sorption of plutonium(VI) by hydroxyapatite

The sorption of Pu(VI) by synthetic hydroxyapatite was determined in NaClO4 media. Pu(VI) sorption was determined to be rapid with equilibrium attained in 2 hours. Equilibrium experiments indicated sorption to be pH dependent with distribution constants, log K-d values, ranging from 4.11 at pH 6 to 5.92 at pH 8.5. Data collected at pH 8.0 with varying total Pu(VI) were fit to the Langmuir isotherm and yielded Langmuir constants of C-a = 0.0147 mole/mole and K = 1.71.10(8) I/mole. Although varying ionic strength did not have an effect on Pu(VI) sorption, a decrease in sorption was evident at high calcium and phosphate concentrations.