Extraction Separation Process of Minor Actinide Elements using Biomimetic Polymer Gel

本研究的目的是通过热摆操作合成能够提取和释放微量锕系元素的仿生聚合物凝胶，并测试软金属（Cd(II)）和微量锕系元素（Am(III)）的可提取性。所得调查结果总结如下：(1)以氮供体配体BTP(2,6-二（3-乙烯基苄基-1 -1,2,4-三唑-5-基）吡啶为共聚体，合成了一种热敏型NIPA （n -异丙基丙烯酰胺）凝胶。提出了一种新的聚合方法——超声聚合法，用于合成NIPA和BTP的均相共聚物。(2)选择性提取三价次锕系元素Am和Cm，需要开发一种能够识别金属离子柔软度的凝胶。本研究测试了BTP-NIPA凝胶对软金属Cd（II）的萃取，并评价了BTP-NIPA凝胶对金属离子柔软度的识别。Cd（II）在LCS以上温度下收缩的凝胶中被提取出来，更多的T（较低临界溶液温度）从LTST以下肿胀的凝胶中释放出来，利用超声照射下聚合的凝胶成功地实现了这种热变萃取(3)当BTP含量增加时，凝胶中形成BTP分支，因为这些BTP分支不作为交联剂。支链BTP分子上提取的Cd（II）不因缩胀相转变而释放。分支结构的形成不利于稳定的热摆抽提作业。为了抑制支链的形成，进一步提高萃取能力，需要开发新的聚合技术。(4)采用与NIPA和磷酸化合物（MR）共聚的仿生凝胶进行了Am（III）的提取试验。Am（III）在温度高于LCST（5℃）时被成功提取，在温度低于LCST（40℃）时被成功释放。反复热摇操作不影响Am（III）的提取能力。这些结果表明，利用仿生凝胶进行热摇萃取对Am（III）的回收是有益的。少

The object of this research is to synthesize biomimetic polymer gels that can extract and release minor actinide elements by thermal-swing operation and to test the extractability of a soft metal (Cd(II)) and a minor actinide (Am(III)). The investigation results obtained are summarized as follows ;(1)A thermosensitive NIPA (N-isopropylacrylamide) gel copolymerized with a nitrogen donor ligand, BTP (2,6-di(3-vinylbenzy1-1,2,4-triazol-5-yl)pyridine), was synthesized as a biomimetic gel. A new polymerization method, ultrasound polymerization method, was proposed for the synthesis of homogeneous copolymer of NIPA and BTP(2) The development of gel that can recognize the softness of metal ion is required for the selective extraction trivalent minor actinides Am and Cm. In this study, the extraction of a soft metal, Cd(II), with BTP-NIPA gel were tested and the recognition of softness of metal ion by BTP-NIPA gel was evaluated. Cd(II) was extracted in the gel shrunken at temperature above LCS … More T (Lower Critical Solution Temperature) and released from that swollen below LTST Such thermal-swing extraction was achieved successfully by use of gel polymerized under the irradiation of ultrasound(3) When the content of BTP was increased, BTP branches were formed in the gel Since these BTP branches did not act as crosslinking agent, Cd(II) extracted on the branched BTP molecules was not released by the phase transition from the shrinking state to the swelling one. The formation of branch structure is undesirable for stable thermal-swing extraction operation. The development of new polymerization technique is required for depressing the branch formation and further enhancing the extraction capacity.(4) The extraction tests of Am(III) were carried out by a biomimetic gel copolymerized with NIPA and a phosphorus acid compound (MR). Am(III) was extracted at temperature above LCST (5℃) and released successfully below LCST (40℃) The extraction ability of Am(III) was not changed by the repetition of thermal-swing operation. These results suggest that the thermal-swing extraction using biomimetic gel is useful for the recovery of Am(III). Less