用放射性示踪技术研究海洋沉积物中铱的吸附和解吸行为及其富集机制  

Study on sorption, desorption behaviors and enrichment mechanism of iridium in marine sediments by radioactive tracer

作　　者：戴雄新[1] 柴之芳[1] 毛雪瑛[1] 欧阳宏[1] 张朝晖[1] 

机构地区：[1]中国科学院高能物理研究所核分析技术开放研究实验室,北京100080

出　　处：《核技术》2000年第3期181-186,共6页Nuclear Techniques

基　　金：国家自然科学基金!29771031;中国科学院重大项目!21039751;核分析技术开放实验室资助

摘　　要：利用放射性示踪技术，结合静态吸附、解吸实验及可见分光光度分析，研究了海洋沉积物一海水体系中铱的吸附及解吸行为。结果表明，在极低的铱浓度范围内，铱的吸附一解吸等温线呈线性，且吸附一解吸不可逆。 IrＣ１２6－形态的铱极易被沉积物所吸附，一旦吸附后又很难解吸下来。沉积物沉积过程中不断地吸附海水中的IrＣ１２6－可能致使铱累积于沉积物中，从而引起铱富集。丹麦鱼粘土对铱的吸附能力弱于近海洋沉积物，说明丹麦鱼粘土高含量铱来源于其它成因机制，如火山或地外成因。By using radiotracer technique, the sorption and desorption behaviors of iridium in marine sediment-seawater system were studied through the sorption and desorption experiments and visible absorption spectrum analysis. The results indicated that, in the range of very low iridium concentration, the sorption and desorption isotherms were linear, and the sorption-desorption process was irreversible. Iridium in the form of IrCl62- was very easy to be sorbed by the sediments. Once being sorbed by the sediments, Ir was hard to be desorbed. In the sedimentary process, the sediment continuously absorbed the species of IrCl62- from the seawater, which might lead to the Ir accumulation in the sediment. The sorption ability of the Danish K/T Fish Clay was weaker than that of the coastal sediment, which indicated that the excessively high Ir content in the Fish Clay might be caused by the other enrichment mechanisms, such as volcanic or extraterrestrial origin.

关 键 词：海洋沉积物 铱 吸附 解吸 富集 放射性示踪技术 可见分光光度分析 

分 类 号：P736.211[天文地球—海洋地质] O657.4[天文地球—海洋科学]