A new method for direct observation of microscale multielemental behavior in waterlogged soil: μXRF-μXAFS combined live soil imaging chamber (LOACH)
A new method for direct observation of microscale multielemental behavior in waterlogged soil: μXRF-μXAFS combined live soil imaging chamber (LOACH)
复制标题
直接观察淹水土壤微尺度多元素行为的新方法：μXRF-μXAFS组合活土成像室（LOACH）
DOI：
10.1016/j.geoderma.2020.114415
复制
发表时间：
2020
期刊：
影响因子：
6.1
通讯作者：
Takahashi Yoshio
中科院分区：
文献类型：
--
作者：
Mitsunobu Satoshi;Hiruta Takuya;Fukudo Jinsuke;Narahashi Yuna;Hamamura Natsuko;Matsue Naoto;Takahashi Yoshio
在本研究中，我们开发了一种新颖的无损方法，即μXRF-μXAFS活体土壤成像室组合方法，可以直接观察淹水土壤（例如淹水稻田）中常见的氧化还原层中金属（类）的局部行为。新设计的土壤室采用钛板和玻璃制成，具有低透气性和高耐腐蚀性，专门用于缺氧环境的淹水土壤的实验。土壤室可以直接安装在同步加速器 μXRF-μXAFS 光束线上。因此，通过这种方法，我们可以在没有物理和化学干扰的情况下观察完整的稻田土壤。 μXRF-μXAFS 分析的应用使我们能够在微尺度上分析土壤元素的元素丰度和化学形态。此外，由于μXRF-μXAFS对各种元素都具有高元素选择性和高适用性，因此我们可以研究目标元素的行为及其与相关元素的关系。在这项研究中，我们应用新方法来研究砷（As）在淹水稻田土壤表面形成的氧化还原层中的行为。砷污染水稻土的 μXRF 成像最新表明，在淹水条件下培养 1 个月，土壤中的砷在表土层中以毫米级强烈积累。此外，As和相关金属的μXAFS分析表明，As的积累与As氧化态随土壤深度的变化以及稻土氧化还原层中最有利的吸附剂（Fe（III）氢氧化物）的共存密切相关。
In this study, we developed a novel non-destructive method, a combined μXRF–μXAFS live soil imaging chamber method, to directly observe the local behavior of metal(loid)s in the oxidative–reductive layer typically found in waterlogged soil such as flooded paddy soil. The newly-designed soil chamber was made of titanium plate and glass with low gas permeability and high corrosion resistance, and thus specializes in the experiment of the waterlogged soil with anoxic environment. The soil chamber can be mounted directly in the synchrotron μXRF–μXAFS beamline. Hence, by using this method, we can observe the intact paddy soil without physical and chemical disturbances. The application of μXRF-μXAFS analysis allows us to analyze the elemental abundances and chemical speciation of soil elements at a microscale. In addition, since the μXRF–μXAFS has both and high elemental selectivity and high applicability for various elements, we can investigate the behavior of target element as well as its relationships with related elements. In this study, we applied the new method to examine the behavior of arsenic (As) in the oxidative–reductive layer formed at the surface of flooded paddy soil. The μXRF imaging of As-contaminated paddy soil newly showed that As in the soil was strongly accumulated in the topsoil layer in a millimeter scale by 1 month incubation under flooded condition. Moreover, the μXAFS analysis of As and related metals indicated that the As accumulation was closely attributed to the change in the oxidation state of As with soil depth and the coexistence of the most favored sorbent (Fe(III) hydroxides) in the oxidative–reductive layer of the paddy soil.