Study on Adsorption of Rare Earth Elements by Kaolinite

Rareearthelements (REEs)werewidelyappliedtotracingthesourcesofmaterialsandtostudyingtheirevolutionprocessesinmanyfieldsofearthscienceinconsiderationoftheirsimilarityandsystematicdiffer enceinchemicalproperties .Furthermore ,lanthanidesarebothimportantprod…     

洱海沉积物孔隙水中溶解有机质的三维荧光光谱特征

文章应用三维荧光光谱技术对洱海沉积物孔隙水中的溶解有机质进行了研究。结果表明，所有样品均含有4个明显的荧光峰，其中A和C为类腐植酸荧光，B和D为类蛋白荧光。荧光强度在沉积物-水界面特别强，在1cm处急剧下降，之后随着沉积深度呈上升趋势。孔隙水溶解有机质均具有强的类蛋白荧光，     

新一代高性能二次离子质谱在地球和空间科学中应用…

自８０年代以来，国际上相继出现的ＳＨＲＩＭＲ，ＩＳＯＬＡＢ１２０及ＩＭＳ１２７０为代表的瓣一代高性能二次离子质谱，它们同时具有高灵敏度和高分辨率的优异性能，从而对地球和空间科学发展产生了重大影响。并将概述在地质年代学，宇宙年代学，同位素地球化学以及环境科学中微区分析已取得的进展及展望在下一世纪的发展。     

Inorganic Speciation of Rare Earth Elements in Chaohu Lake and Longganhu Lake, East China

Geochemical behaviors of the rare earth elements(REEs)in river and lake water bodies are dependentmainly on water chemistry and other factors,andhence their variationsin concentration and compositionreflect changes of various environmental variables.There…     

ICP-MS测定表生水体稀土过程中pH值对酸性膦萃取稀土效率的影响

针对目前最常用的液-液萃取、ICP-MS测定法检测表生水体中微量稀土元素方法,研究了不同pH值条件下,酸性膦(65%HDEHP和35%H2MEHP)自表生水体中萃取稀土元素(REEs)的回收率。结果表明,在pH1~4的范围内,不同性质的水体(湖泊、河流、地下水)有不同的REEs回收率。其中湖水在pH 1.8~3.7有90%以上的回收率,最高回收率为93.64%;河水在pH 2.1~3.5范围内有90%以上的回收率,最高回收率为95.52%;地下水仅在pH 1.3~1.5时回收率超过90%,最高回收率为97.61%。说明在萃取不同表生水体中稀土元素时,需要调到特定的pH值才能得到最好的萃取效果。     

电感耦合等离子体质谱测量硒的研究进展

近年来,准确测量生物、食品、环境、地质等样品中的硒元素含量、同位素组成及其各种形态受到越来越多的关注。随着质谱技术的发展,电感耦合等离子体质谱(ICP-MS)技术成为硒的各种特性量研究和测量的重要手段,使其在生命科学、环境地球化学、生物、营养等研究中有着广泛的应用前景。本文综述了ICP-MS法应用于硒同位素比值,元素总量以及多种形态测量技术方面的最新研究进展。     

Strontium isotopic geochemistry of the Changjiang estua-rine waters: Implications for water-sediment interaction

The Sr concentrations and 87Sr/86Sr ratios have been measured for the Changjiang es-tuarine waters with a main purpose to understand physical and chemical processes at the estuary. The result shows that the Changjiang River water has higher Sr concentration (150 ng/g) and lower 87Sr86Sr ratio (0.7105) when compared with the average values (0.7119 for 87Sr/86Sr and 78ppb for Sr, respectively) of large world rivers. In the mixing process, no simple mixing of two end-members has been found according to the variations of Sr concentration and isotope ratios. There is an abrupt rise of Sr isotope ratios at the salinity about 1 mg/g during river-sea water mixing at the estuary. This abrupt rise of Sr isotope ratios is mostly ascribed to the strong water-sediment interaction, because there exists the same rise of suspended particulate materials due to energetic resuspension of bottom sediments.     

Review of Rare Earths and Fluid-Rock Interaction

As demonstrated by a great amount of geologic and experimental evidences, RE of rock systems may be mobilized during fluid-rock interaction when solutions are rich in F^-, Cl^-, CO3^2- , HCO3^-, CO2, HPO4^2- , HS^-,S^2- , SO4^2- , though little has been known about the mobilizing mechanism of these anions or ligands. The fractionation of RE resulted from hydrothermal alterations, i. e., fluid-rock interactions, are distinctive. One set of field data implies the preferential mobility of the LRE, while another set of field observations demonstrates the dominant mobilization of the HRE, and some theoretical prediction is not consistent with the field evidence. The Eu anomalies caused by fluid-rock interaction are complex and compelling explanation is not available due to inadequate experimental approaches. To know the exact behavior of RE during fluid-rock interaction and to solve the contradiction between some theoretical predictions and field observations, the following works remain to be done : ( 1 ) experimental investigations of RE mobility and fractionation as a function of fluid chemistry, e.g., the activity of F^-,Cl^-, CO3^2- , HCO3^-, CO2, HPO4^2- , HS^-, S^2- , SO4^2- , etc. ; (2) experimental determination of RE mobility and fractionation as a function of T, P, pH, Eh and water/rock ratios; (3) investigation of the mechanism and the controlling factors of RE partitioning between hydrothermal minerals and fluids. It was demonstrated that RE mobility is a potentially useful method for exploration.     

Behaviors of Rare Earths during Fluid-Rock Interaction and Its Significance of Geochemistry

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Enrichment and Release of Rare Earth Elements during Weathering of Sedimentary Rocks in Wujiang Catchments, Southwest China

Thirteen weathering profiles of sedimentary rocks such as limestone, dolomitic limestone, dolomite, sillicalite, black shale and purple sandrock from Wujiang catchments were selected for study on enrichment and release behavior of rare earth elements （REE） during weathering, and its impact on plant growth and riverine REE distribution in the catchments with methods of hierachical cluster analysis and mass balance calculation in order to set a basis for riverine material source research and agricultural production. The results show that the enrichment degree of REE in calcareous soils from the Wujiang catchments is much higher than that of limestone, yellow soil, upper continental crust （UCC）, China soil （CS） and world soil （WS）. The ability of enrichment and release of REE is partly controlled by distribution of REE in bedrocks, contents and adsorption ability of organic matters, clay minerals and Fe-oxides/hydroxides in weathering profiles. The REE released from weathering of carbonate rocks and clastic rocks can be absorbed and utilized by local plants. The results also reveal that release of REE and Fe mainly from weathering of carbonate rocks and partly from clastic rocks exerts an important control on riverine REE distribution.