Selective Liquid‐Liquid Extraction of Uranium by Phosphoramidate‐Group Bearing Ionic Liquid. Issue 26 (10th July 2019)

• Record Type: Journal Article
• Authors: Saha, Abhijit; Tiwari, Nidhi; Deb, Sadhan Bijoy; Saxena, Manoj Kumar
• Is Part Of: ChemistrySelect. Volume 4:Issue 26(2019)
• Page Start: 7691
• Page End: 7697
• Publication Date: 2019-07-10
• Subjects: Distribution ratio -- EXAFS spectroscopy -- Infrared spectroscopy -- Separation factor -- Task specific ionic liquid; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201901933
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: Extraction of pure uranium (U) from its ore or spent nuclear fuel and separation of U for trace impurities characterization of nuclear fuels are the processes resulting into the accumulation of large amounts of low boiling and volatile organic waste. The limited reusability and degradation (chemical and radiation induced) of these waste solutions turning out to be an environmental threat. The authors have addressed this issue by developing an eco‐friendly, simple and selective liquid‐liquid extraction (LLE) procedure for U employing a phosphoramidate group bearing task specific ionic liquid (TSIL). Optimization of various LLE parameters resulted in high distribution ratio (D) value of 174±5 for U when extracted from 5 mol L −1 HNO3 medium. A detailed study on the infrared and extended X‐ray absorption fine structure spectroscopy of U loaded ionic liquid phase reveals the extraction mechanism. Such high DU value resulted in high separation factors for U with respect to the elements which are commonly present in the ore, processed nuclear fuel and spent nuclear fuel. The structural integrity and metal ion extractability of the TSIL is found to remain unaffected when irradiated up to an absorbed dose of 400 kilogray (kGy). Sodium carbonate solution is found to back‐extract ≥ 95% of U from the ionic liquid phase and regenerate it for further usage. Abstract : A task specific ionic liquid (TSIL) viz., N‐propyl(diphenylphos‐phoramidate)trimethylammonium bis(trifluoromethanesulfonyl)imide, aided liquid‐liquid extraction (LLE) procedure for uranium has been developed. The infrared and extended X‐ray absorption fine structure spectroscopic studies have proven the coextraction of two different uranium complexes in the IL medium. The LLE of U from 5.0 mol L −1 HNO3 medium is found to provide very good distribution ratio and separation factor values. The TSIL is also found to be stable upto an absorbed dose of 400 kilogray (kGy).