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  • Author or Editor: Bao Bo-Rong x
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Abstract  

A systematic investigation has been carried out on the extractive behavior of N,N'-dihexanoylpiperazine (DHPEZ) with respect to U(VI) in five diluents, from aqueous nitric acid media. The variation of U(VI) distribution ratio with the concentrations of aqueous nitric acid, extractant, salting-out agent and with temperature has been investigated and discussed. The increasing order of extractive ability of DHPEZ towards U(VI) is: chloroform, carbon tetrachloride, 1,4-dimethyl-benzene, toluene, benzene. The composition of the extracted species and extraction constants as well as the enthalpy changes are given.

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Abstract  

The effect of diluents on the extraction of uranium(VI) with petroleum sulfoxides (PSO) was studied. The decreasing order of extraction ability of PSO is as follows: benzene, toluene, cyclohexane, heptane, kerosene, carbon tetrachloride and chloroform. The effect of temperature on the extraction equilibrium was also investigated and enthalpy of the extraction was obtained. The relationship between the extraction equilibrium constantsK ex and the physical parameters of diluents can be derived.

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Abstract  

The liquid-liquid extraction of uranium(VI) from aqueous nitric acid with bis(octylsulfinyl)methane (BOSM) has been studied over a wide range of conditions. The extracted species appear to be UO2(NO3)2·2BOSM. It was found that the extraction increased with increasing nitric acid concentration up to 8.5 mol/l and then descreased. Extraction also increased with increasing extractant concentration. The influence of temperature and salting-out agent concentration on the extraction equilibrium has also been investigated, and the enthalpy of the extraction reaction was estimated.

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Abstract  

The extraction of uranium (VI) from nitric acid by N-octanoylpyrrolidine (OPOD) in toluene has been investigated at varying concentrations of nitric acid, extractant, salting-out agent LiNO3 and at different temperatures. The mechanism of extraction is discussed in the light of the obtained results.

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Abstract  

The liquid-liquid extraction behavior of uranium(VI) from aqueous nitric acid with bis(octylsulfinyl)ethane (BOSE) in 1,1,2,2-tetrachloroethane has been studied over a wide range of conditions. The extracted species appears to be UO2(NO3)2·2BOSE. It was found that the extraction increases with increasing nitric acid concentration up to 7 mol/l and then decreased. Extraction also increases with increasing extractant concentration. The influence of temperature and salting-out agent concentration on the extraction equilibrium and stripping of uranium(VI) was also investigated and the enthalpy of the extraction reaction was obtained.

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Abstract  

A novel extractant, N, N-didecanoylpiperazine (DDPEZ), was synthesized for the first time. The extraction of U(VI) by DDPEZ from aqueous nitric acid media in carbon tetrachloride has been studied. The dependence of extraction distribution ratio on concentration of aqueous nitric acid, extractant, salting-out agent and temperature was investigated and the enthalpy of the extraction was calculated.

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Abstract  

N,N-dialkylamides having ethyl (DEDOA), butyl (DBDOA) and octyl (DODOA) groups as the alkyl substituents were synthesized in order to investigate their selectivity and capability in the extraction from acidic nitrate media in nuclear reprocessing. The extraction distribution coefficients of U(VI) with the amides in toluene decrease in the order of DODOA>DBDOA>DEDOA. The structure of the extracted species was suggested from the dependence of the distribution ratio on the concentration of the extractant, with the aid of FT-IR spectra. The structural effect on the extraction capability of U(VI) was discussed in terms of the molecular modelling. The effects of temperature on the distribution ratios were also considered, and the extraction reaction enthalpy was calculated.

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Abstract  

A new symmetrical diamide, the straight-chain alakyl substituted neutral tetrabutyladipicamide (TBAA) has been synthesized, characterized and used for the extraction of U(V) and Th(IV) from nitric acid solutions in a diluent composed of 50% 1,2,4-trimethylbenzene (TMB) and 50% kerosene (OK). Extraction distribution coefficients of U(VI) and Th(IV) as a function of aqueous nitric acid concentration, extractant concentration and temperature have been studied. Back-extraction of U(VI) and Th(IV) from organic phases by dilute nitric acid has been undertaken. From the data, the compositions of extracted species, equilibrium constants and enthalpies of extraction reactions have also been calculated.

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Abstract  

N,N,N,N-tetrabutylsuccinylamide (TBSA) in a diluent composed of 50% trimethylbenzene (TMB) and 50% kerosene (OK) can extract uranyl (II) ion from nitric acid solution. The results of extraction study suggested the formation of the 121 uranyl (II) ion, nitrate ion and N,N,N,N-tetrabutylsuccinylamide complex as extracted specis. The values of thermodynamic functions have been calculated.

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Abstract  

A novel extractant, N,N-dilauroylpiperazine (DLPEZ), was synthesized for the first time. The extraction of uranium(VI) with the novel extractant in carbon tetrachloride from aqueous nitric acid media has been studied. The dependence of extraction distribution ratio on the concentration of aqueous nitric acid, extractant, salting-out agent and temperature was investigated and the enthalpy of the extraction was determined.

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