Sorption Distribution Coefficient of Pu(Ⅳ) and Pu(Ⅴ) in Sand Soil

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(K_d) of Pu(Ⅳ) and Pu(Ⅴ) in the sand soil were studied by batch experiments,K_d of Pu(Ⅳ) is about 5.5×10³ mL/g to 4×10⁴ mL/g,K_d of Pu(Ⅴ) is 3.2×10³ mL/g to 1.1×10⁴ mL/g.In conclusion,K_d 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.