Extraction Separation Process of Minor Actinide Elements using Biomimetic Polymer Gel

本研究的目的是合成能够通过热摆动操作来提取和释放微量鳗系元素的仿生聚合物凝胶，并测试软金属(Cd(II))和微量鳗系元素(Am(III))的萃取性。主要研究结果如下：(1)合成了N-异丙基丙烯酰胺(N-异丙基丙烯酰胺)与氮供体(2，6-di(3-vinylbenzy1-1，2，4-triazol-5-yl)pyridine)，共聚的温敏凝胶作为仿生凝胶。提出了一种合成NIPA和BTP均相共聚物的新的聚合方法--超声聚合法。(2)选择性萃取Am和Cm的三价次元素Am和Cm需要一种能够识别金属离子柔软性的凝胶。本研究测试了BTP-NIPA凝胶对软金属Cd(II)的萃取作用，评价了BTP-NIPA凝胶对金属离子软性的识别能力。Cd(II)在高于lcs…的温度下收缩的凝胶中被提取(3)当BTP含量增加时，由于BTP支链不起交联剂的作用，BTP支链不起交联剂的作用，在支链BTP分子上提取的Cd(II)不会从收缩状态向溶胀状态的相变中释放。分支结构的形成不利于稳定的热摆萃取操作。需要开发新的聚合技术来抑制支化形成，进一步提高萃取能力。(4)用NIPA与磷酸化合物(MR)共聚的仿生凝胶进行了Am(III)的萃取实验。Am(III)在Lcst以上(5℃)被萃取，在Lcst以下(40℃)被成功释放。重复热摆动操作不改变Am(III)的萃取能力。这些结果表明，仿生凝胶热摆动萃取法对Am(III)的回收是有效的。较少

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