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Removal of ^<137>Cs from ecosystems using phytoremediation in former Soviet Union

前苏联利用植物修复从生态系统中去除 ^<137>Cs

基本信息

批准号：
13574019
负责人：
FUNAKAWA Shinya
金额：
$ 4.42万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

The in sib distribution patterns of clay minerals and thermodynamic analysis of quasi-soil solution composition reveal the weathering, sequence of 2:1 minerals in humid Asia as follows : In moderately to highly weathered soils, dioctahedral mica inherited from parent materials is a major source of 2:1 minerals in soil clays. In Thailand, under moderately acidic conditions with annual precipitation of less than 1500 mm, mica is considered to be directly weathered to kaolin minerals with forming few expandable 2:1 minerals, if any. In contrast, under strongly acidic conditions in Indonesia and/or Japan with higher precipitation, mica tends to firstly weathered to expandable 2:1 minerals and then to kaoliniteSuch expandable 2:1 minerals formed under acidic conditions can immobilize Cs^+ extensively. In addition, FES of weathered mica can immobilize Cs^+ ion In Thailand and Ukraine, Cs immobilizing capacities of the soils are relatively small and vary depending on the occwYence of FFS in m … More ica minerals. Judging firm the results obtained for Cs-adsorption and desorption behaviors under different ionic strengths, FES immobilize Cs independently of I of a soil solution while collapsed interlayer sites also immobilize Cs but are, to some degree, affected by 1, i.e., increased ionic concentration of surrounding solution may enhance desarption of Cs^+ once immobilized. Such properties of clay minerals on Cs adsorption are possibly modified through soil formation, i.e., hydroxy-interlayering and/or extensive weathering of mica mineralsGenerally expandable 2:1 minerals with modeltely-to highly-charged layers can immobilize Cs^+ most strongly. This is the case that occurs in Japan and/or Indonesia among the present study Fortunately such soils in Japan are mostly modified by hydroxy interlayering, which can decrease the chance of irreversible Cs immobilization. Moreover, the Cs^+ ion once immobilized in the collapsed layers of expandable 2:1 minerals can be desorbed if solution I increases. In this sense, these is a room for trying phytoremediacion in Japanese and/or Indonesian soils,although high dose of soluble salts may be required if the main target for extraction of Cs^+ is collapsed 2:1 layers. On the other hand, FES of weathered mica can fix Cs^+ ion independently of solution L In rum, Cs^+ ion once retained by mica minerals would not be released by the change of 1 of surrounding solution In the soils of Ukraine and Thailand, such mica minerals are considered to be mainly responsible for Cs immobilization. It is, therefore, quite difficult to remove Cs^+ ion firm these soils if a fairly large amount of mica minerals is present Less

粘土矿物的同源分布模式和准土壤溶液组成的热力学分析揭示了亚洲湿润地区2：1矿物的风化顺序为：在中-高度风化土壤中，母质继承的双八面体云母是土壤粘土中2：1矿物的主要来源。在泰国，在年降水量小于1500毫米的中等酸性条件下，云母被认为直接风化成高岭土矿物，几乎没有形成可膨胀的2：1矿物。而在降水较多的印度尼西亚和日本的强酸性条件下，云母往往先风化成可膨胀的2：1矿物，再风化成高岭石。在酸性条件下形成的这种可膨胀的2：1矿物可以广泛地固定Cs~+。此外，在泰国和乌克兰，风化云母中的FeS对Cs~(++)具有固定作用，土壤中Cs的固定化能力相对较小，且随风化云母中FeS在m…中的含量不同而不同更多的ICA矿物。从不同离子强度下Cs的吸附和解吸行为来看，FeS对Cs的固定不依赖于土壤溶液中的i，而塌陷的层间位也固定Cs，但在一定程度上受1的影响，即提高周围溶液的离子浓度可促进Cs~+的脱附。粘土矿物对Cs的这种吸附性能可能通过土壤形成而改变，即云母矿物的羟基插层和/或广泛的风化。通常可膨胀的2：1矿物具有模型到高电荷层，对Cs^+的固定作用最强。在本研究中，日本和/或印度尼西亚的情况就是如此。幸运的是，日本的这类土壤大多是通过羟基插层改性的，这可以减少不可逆Cs固定的机会。此外，一旦Cs~+离子固定在可膨胀的2：1矿物的坍塌层中，如果溶液I增加，则Cs~(++)离子可以被解吸。从这个意义上说，这是在日本和/或印度尼西亚土壤中尝试植物修复的空间，尽管如果Cs^+的主要提取目标是塌陷的2：1层，可能需要高剂量的可溶盐。另一方面，风化云母中的FeS能独立于L溶液固定朗姆酒中的Cs~(++)离子，在乌克兰和泰国土壤中，一旦被云母矿物保留的Cs~(++)离子不会因周围溶液的变化而释放，这种云母矿物被认为是Cs固定的主要原因。因此，如果相当大量的云母矿物存在较少，则很难去除这些土壤中的Cs^+离子