Liquid-liquid Extraction of U(Ⅵ) and Pu(Ⅳ) with 2,2′-((4-Ethoxy-1,2-phenylene) bis (oxy)) bis (N,N-bis(2-ethylhexyl)acetamide)

Abstract

To develop a highly selective extractant for Pu(Ⅳ), 2,2′-((4-ethoxy-1,2-phenylene)bis(oxy)) bis (N,N-bis(2-ethylhexyl)acetamide), short for 4-EthoxyBenzoDODA, has been evaluated as a novel extractant in n-dodecane diluent for the extraction of U(Ⅵ) and Pu(Ⅳ). The effect of contact time of two phases, HNO3 concentration and extractant concentration on the distribution ratios of U(Ⅵ) and Pu(Ⅳ) was investigated. Acid uptake studies suggested that 4-EthoxyBenzoDODA (KH=0.14) was less basic as compared to BenzoDODA (KH=0.44), making it more conducive to selectively extract Pu(Ⅳ) with stronger ionic potential. Extraction experiments showed that the maximum of SFPu/U, SFPu/Eu were 6.9, 223 respectively. Slope analysis indicated extraction of 1∶1 (ML) species with U(Ⅵ) and mixed 1∶1 (ML) and 1∶2 (ML2) species with Pu(Ⅳ) at 4.0 mol/L HNO3 98% of Pu in the loaded organic phase can be stripped to the aqueous phase using reductive stripping agent such as hydrazine nitrate and hydroxylamine nitrate. The results showed that the 4-EthoxyBenzoDODA exhibited good selectivity toward Pu.

Keywords

• uranium
• plutonium
• selective extractant
• separation factor