Extraction behavior of thorium(Ⅳ) and uranium(Ⅵ) from nitric acid(HNO_3) was studied using N,N,N',N'-tetraoctyldiglycolamide(TODGA) as extractant in different ionic liquids, and isooctane as comparison.Slope...Extraction behavior of thorium(Ⅳ) and uranium(Ⅵ) from nitric acid(HNO_3) was studied using N,N,N',N'-tetraoctyldiglycolamide(TODGA) as extractant in different ionic liquids, and isooctane as comparison.Slope analyses with varying HNO_3 concentrations and diluents revealed the extraction mechanism. With increasing length of alkyl chain and HNO_3 concentration, the extraction mechanism of TODGA/IL system changed from cation exchange to neutral complex and/or anion exchange,and the molar ratio between TODGA and metal ions varied gradually from 2:1 to 1:1 for Th(Ⅳ) and 3:1 to 1:1 for U(Ⅵ). The kinetics and thermodynamic studies of Th(Ⅳ)and U(Ⅵ) by the best TODGA/[C_2mim][NTf_2] system showed that the extraction equilibrium was reached within 2 h and extraction reactions were endothermic. Compared to TODGA/isooctane system, TODGA/[C_2mim][NTf_2]system presented higher radiation stability under c-irradiation. Therefore, it would have a promising application in spent fuel reprocessing.展开更多
基金financially supported by the National Natural Science Foundation of China(No.11475112)the Ph.D. Programs Foundation of Ministry of Education of China(No.20130073120051)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning
文摘Extraction behavior of thorium(Ⅳ) and uranium(Ⅵ) from nitric acid(HNO_3) was studied using N,N,N',N'-tetraoctyldiglycolamide(TODGA) as extractant in different ionic liquids, and isooctane as comparison.Slope analyses with varying HNO_3 concentrations and diluents revealed the extraction mechanism. With increasing length of alkyl chain and HNO_3 concentration, the extraction mechanism of TODGA/IL system changed from cation exchange to neutral complex and/or anion exchange,and the molar ratio between TODGA and metal ions varied gradually from 2:1 to 1:1 for Th(Ⅳ) and 3:1 to 1:1 for U(Ⅵ). The kinetics and thermodynamic studies of Th(Ⅳ)and U(Ⅵ) by the best TODGA/[C_2mim][NTf_2] system showed that the extraction equilibrium was reached within 2 h and extraction reactions were endothermic. Compared to TODGA/isooctane system, TODGA/[C_2mim][NTf_2]system presented higher radiation stability under c-irradiation. Therefore, it would have a promising application in spent fuel reprocessing.
