Abstract:

Pu exists in four different oxidation states(Ⅲ, Ⅳ, Ⅴ, Ⅵ) with in the Eh(redox potential) and pH ranges of natural environment. Pu(Ⅳ) in Pu(OH)4 form and Pu(Ⅴ) in PuO2(H2O)+n form are the dominant oxidation states under equilibrium conditions for groundwater compositions. The sorption distribution coefficients(Kd) of Pu(Ⅳ) and Pu(Ⅴ) in the sand soil were studied by batch experiments, Kd of Pu(Ⅳ) is about 5.5×103 mL/g to 4×104 mL/g, Kd of Pu(Ⅴ) is 3.2×103 mL/g to 1.1×104 mL/g. In conclusion, Kd values of Pu(Ⅳ) in the sand soil were larger than those of Pu(Ⅴ). Such distribution coefficients increase with the increase of amount of clay in sand soil and the decrease of particle size.

Key words: Pu(Ⅳ), Pu(Ⅴ), Sandy soil, Distribution coefficient