摘要
2,9-Diamide-1,10-phenanthroline(DAPhen)ligands represent a new family of tetradentate extractants given their strong affinity to actinides and the CHON principle.Among this family,N,N′-diethyl-N,N′-ditolyl-2,9-diamide-1,10-phenanthroline(Et-TolDAPhen),initially reported by us,exhibits excellent selectivity towards actinides(U,Th,Am,Pu)over lanthanides and thus can be potentially applied in the group actinide extraction(GANEX)process for the group separation of actinides.In this article,by tailoring the lengths of alkyl chains,we synthesized other four DAPhen ligands with different substitute groups in the diamide moieties,and characterized the relationship between properties and substitute groups of DAPhen ligand.The extraction results show that three of the ligands exhibit high performance in UO_2^(2+)extraction from an acidic solution and the extracted UO_2^(2+)can be easily stripped by only using ultrapure water.Spectrophotometry titration confirms that UO_2^(2+)combined with all the four ligands in 1:1 mode.The extended X-ray absorption finestructure(EXAFS)study shows that six donor atoms comprise the first equatorial shell of the UO_2^(2+)ions bonded by the DAPhen ligands,among which two nitrogen and two oxygen atoms are from the DAPhen ligand,while other two oxygen atoms are from one nitrate ions.This article promises to provide basic data for assessing the feasibility of this kind of DAPhen ligands applied in actinides separation from nuclear wastes.
2,9-Diamide-1,10-phenanthroline（DAPhen）ligands represent a new family of tetradentate extractants given their strong affinity to actinides and the CHON principle.Among this family,N,N＇-diethyl-N,N＇-ditolyl-2,9-diamide-1,10-phenanthroline（Et-TolDAPhen）,initially reported by us,exhibits excellent selectivity towards actinides（U,Th,Am,Pu）over lanthanides and thus can be potentially applied in the group actinide extraction（GANEX）process for the group separation of actinides.In this article,by tailoring the lengths of alkyl chains,we synthesized other four DAPhen ligands with different substitute groups in the diamide moieties,and characterized the relationship between properties and substitute groups of DAPhen ligand.The extraction results show that three of the ligands exhibit high performance in UO2^2＋ extraction from an acidic solution and the extracted UO2^2＋can be easily stripped by only using ultrapure water.Spectrophotometry titration confirms that UO2^2＋ combined with all the four ligands in 1：1 mode.The extended X-ray absorption finestructure（EXAFS）study shows that six donor atoms comprise the first equatorial shell of the UO2^2＋ ions bonded by the DAPhen ligands,among which two nitrogen and two oxygen atoms are from the DAPhen ligand,while other two oxygen atoms are from one nitrate ions.This article promises to provide basic data for assessing the feasibility of this kind of DAPhen ligands applied in actinides separation from nuclear wastes.
基金
supported by the National Natural Science Foundation of China (21471153, 21777161, 21477130, 21790373)
the Youth Innovation Promotion Association, Chinese Academy of Sciences and the Science Challenge Project (JCKY2016212A504)
