Investigation On Synthesis And Extraction Of Sr²⁺and Nd³⁺ By Calix[n]arene Derivatives

Nowadays, spent fuel reprocessing is one of the most difficult step in thecirculation process of nuclear fuel. In spent fuel reprocessing process, separationmaterials are of great importance for the extraction of Sr2+and Nd3+. Based on theexcellent irradiate stability, chemical stability, thermal stability as well as easiermodification performance of calixarene, it has a promising research and applicationvalue in the aspect of the metal extraction separation. So calixarene can be used as anew extractant to recognise Sr2+and Nd3+in the high-level radioactive waste liquid.Four kinds of calixarene derivatives were synthesized through a six-step reaction.The molecular structure of the above four calixarene derivatives were characterizedand confirmed by FT-IR, MS,1H NMR and TG-DTA, and the compounds obtainedwere final objective products.In this thesis, the calixarene derivatives were synthesized and their extractiveproperties on strontium, neodymium and other elements were investigated. This studyfocused on the effect of diluent, nitric acid concentration, contact time, extractantconcentration, metalion concentration and temperature on the extraction performanceof Sr2+and Nd3+. The results showed that the extraction effect was better when usingdichloromethane as diluent. When four kinds of calixarene derivatives were used toextract Sr2+and Nd3+, the extraction rate was changing with the increase of nitrateconcentrations and when nitrate concentration was3.00mol/L and4.00mol/L, theextraction performance of four kinds of calixarene derivatives was better. Withcontact time increasing, the extraction rate of Sr2+, Nd3+gradually stabilized after90min. It was indicated that the reaction system was close to equilibrium when thecontact time was90min. By slope analysis method, the composition of the fourextracted complexes were deduced from the studies of factors such as extractantconcentration and ion concentration, which affected the distribution coefficient. Thethermodynamics parameters including ΔH, ΔS and ΔG were determined by theeffects of temperature on distribution coefficient. And the process of the calixarenederivatives extraction Sr2+and Nd3+were exothermic reactions. Besides, thefunctional groups of calixarene derivatives can improve extractive performancegreatly. The extraction ability of four kinds of calixarene derivatives for Sr2+and Nd3+ from strong to weak was followed by CalixEPO, CalixSPO, CalixFPO and CalixFMO.The above conclusions can provide a reliable theoretical foundation and experimentalbasis for extracting Sr2+and Nd3+from high level liquid waste. And the extractionperformance of four kinds of calixarene derivatives for other metal ions was studiedas well.