Synthesis Of Preparation Of Carboxylic Acid Functionalized Ionic Liquids And Homogeneous Extraction Performances For Eu(?)

Treatment and disposal of high-level waste liquids is one of the most critical aspects of the nuclear fuel cycle process.Americium has long half-life,strong radioactivity and high toxicity,and it is one of the key nuclides that affect the disposal and disposal of high-level waste liquid.The effective separation of americium is a hotspot and difficulty in the current nuclear fuel cycle research.The ionic liquid has the advantages of lower vapor pressure,stronger dissolving power,etc.It is a promising environment-friendly green solvent.Europium has similar oxidation states,ionic radii,and coordination chemistries but does not have radiotoxicity and can be used as a non-radioactive substitute for americium.In this paper,we study the behavior of the new carboxylic acid functionalized ionic liquids for extracting europium in liquid phase.The details are as follows:?1?Three kinds of carboxylic acid-functionalized ionic liquids,Bis?trifluorom ethane sulfonimide?betaine[Hbet][Tf₂N],Bis?trifluoromethanesulf onimide?N-?carboxymethyl?-N,N-dimethyl ethanaminium[DHbet][Tf₂N]and Bis?trifluorom ethane sulfonimide?N-?carboxyethyl?-trimethylammonium[THbet][Tf₂N]were synthesized by the reaction of N-alkylation and substitution using tertiary amines as raw materials.Two of them have not been reported.Fourier-transform infrared?FT-IR?and nuclear magnetic resonance?NMR?techniques were used to identify and characterize it.?2?Using a static test method,[Hbet][Tf₂N],[DHbet][Tf₂N],[THbet][Tf₂N]was used as the extractant,and the pH of the solution,extraction contact time,initial concentration of Eu³⁺,and temperature were systematically investigated.The effects of ionic strength and other factors on the extraction of Eu³⁺from three ionic liquids were calculated and the thermodynamic parameters were calculated.The extraction mechanism was also studied by slope method.The structure of the extracted complex was calculated and subjected to multi-stage countercurrent extraction experiments.Homogeneous extraction experiments showed that the optimal extraction pHs of[Hbet][Tf₂N],[DHbet][Tf₂N]and[THbet][Tf₂N]for Eu³⁺were 3,3 and 4,respectively,and the extraction equilibrium time was 20 min.Ionic strength has little effect on extraction.The thermodynamic function of the extraction indicates that the extraction process cannot proceed spontaneously and endothermically.The upper critical solution temperature?UCST?during the homogeneous extraction was different,being 333.15 K,358.15,and 343.15 K,respectively.The slope study showed that the structure of the extracts was 2Eu?NO₃?₃·0.5IL.It also shows good results in multi-stage countercurrent extraction and meets the requirements of industrial processing.In summary,the three carboxylic acid-functionalized ionic liquids have a certain ability to separate americium.This study provided new materials and new methods for the separation of americium from high-level liquid wastes.