A novel extractant 2-Ethylhexyl Bis(2-ethylhexyl)phosphinate for cerium(IV) and fluorine extraction from nitric acid system

Abstract

A novel extractant, 2-ethylhexyl Bis(2-ethylhexyl)phosphinate (EHBEHP, abbreviated as B), was synthesized for the extraction of Cerium(IV) (Ce(IV)) and fluorine (F(I)) from nitric acid (HNO3) media. The effects of HNO3 concentration, extractant concentration, F(I) concentration and the temperature on the Ce(IV) and F(I) extraction were studied and discussed. The experimental results show that EHBEHP has a strong ability to extract Ce(IV), while the presence of F(I) decreases the extraction ability of Ce(IV). The extraction process had nothing to do within the studied temperature range. The extraction of HNO3, Ce(IV) and Ce(IV)-F(I) were studied respectively, and the extracted complexes were found to be 2HNO3·EHBEHP, Ce(NO3)4·2EHBEHP and Ce(HF)(NO3)4·EHBEHP, individually. The extraction mechanisms were determined according to slope analysis method. Saturation loading capacity of Ce(IV) and F(I) extracted by 0.867 mol/L EHBEHP in HNO3 system was about 50.98 g/L and 5.67 g/L, respectively. The stripping experiment shows that 95.3% of stripping efficiency of Ce(IV) can be obtained with 2.4% H2O2. The FT-IR of extracted complexes were measured and characterized. EHBEHP shows higher extraction ability and saturation loading capacity compared with DEHEHP.