Extraction Separation Process of Minor Actinide Elements using Biomimetic Polymer Gel

点击翻译按钮获取中文摘要

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