abstract
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Solvent extraction of Np(V) from nitric acid solution by n-octyl(phenyl)-N, N-diisobutyl-carbamoylmethylphosphine oxide (CMPO) in the presence and absence of tri-n-butyl phosphate (TBP) has been studied using decalin and n-dodecane as diluents. Without the TBP, Np( V ) can be extracted using CMPO in decalin with extraction equation :
NpO2+(a)+NO3-(a)+2CMPO(o)=NpO2(NO3)2CMPO(o)
The maximum Np(V) distribution ratio using 0.65 M CMPO in decalin from 2 M nitric acid is 4. The net effect of TBP to CMPO at 2M nitric acid is slight suppression of Np(V) distribution ratio. However, at low CMPO concentration (0.2 M ?? ) after the Np(V) distribution ratio reaches the minimum value, the distribution ratio gradually increases as the TBP concentration increases. No synergistic interaction of CMPO and TBP has been observed.