天然海水中 ~(238)U、~(234)Th 的富集、纯化与测定

  • 摘要: 以232U-228Th平衡溶液为产额示踪剂,利用Fe(OH)3共沉淀法富集大体积海水中的U、Th同位素,并通过阴离子交换树脂“双柱法”进行分离、纯化。238U、234Th的放射性活度分别用α能谱仪和β计数仪测定,两台仪器间的相对探测效率用钍同位素标准源校正。由该法获得南沙海域、南海东北部海域、厦门湾塔角附近海域以及九龙江口表层水中溶解态、颗粒态238U、234Th的放射性浓度,讨论了各相238U、234Th的空间分布变化。该研究为海洋真光层颗粒动力学和海洋新生产力的同位素示踪研究奠定了方法学基础

     

    Abstract: ENRICHMENT,PURIFICATIONANDDETERMINATIONOF238UAND234ThINNATURALSEAWATERChenMinHuangYipuQiuYusheng(DepartmentofOceanography,XiamenUniversity,361005)ABSTRACTAprocedurehasbeendevelopedfordeterminationof238Uand234Thinnaturalseawaterandparticulatematerial.Intheprocedure,thesamplesarespikedwith232U-228Thequilibri-umtracertodeterminethechemicalyields.BothUandTharecoprecipitatedwithferrichy-droxidefromlargevolumeseawaterandseperatedfromeachotherbyusing“two-column”ionexchangetechniques.Theiractivitiesarecountedbyanα-spectrometerandalowback-groundβ-counter.Therelativecountingeficiencybetweenthesetwodetectorsisintercali-bratedbytwothoriumstandardsolutions.Thegeochemicalbehaviorofdissolvedandpartic-ulate238U,234Thinfourseaareasarestudied.Thisworkhaslaiddownamethodologicalfoundationforstudiesonparticledynamicsinmarineeuphoticzoneandmarinenewproduc-tionbyisotopictracers.Keywordsseawater238U234Thenrichmentpurificationdetermination

     

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