Factors Controlling the Fractionation and Seasonal Mobility Variations of Ga and In in Systems Impacted by Acidic Thermal Waters : Effects of Thermodynamics and Bacterial Activity
Factors Controlling the Fractionation and Seasonal Mobility Variations of Ga and In in Systems Impacted by Acidic Thermal Waters : Effects of Thermodynamics and Bacterial Activity
复制标题
受酸性热水影响的系统中控制 Ga 和 In 的分馏和季节性迁移变化的因素：热力学和细菌活性的影响
DOI：
10.1007/s10498-018-9328-z
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发表时间：
2018
影响因子：
1.6
通讯作者：
Scott A Wood
中科院分区：
文献类型：
--
作者：
Yasumasa Ogawa;Daizo Ishiyama;Naotatsu Shikazono;Koichi Suto;Chihiro Inoue;Noriyoshi Tsuchiya;Bernhardt Saini-Eidukat;Scott A Wood
这项工作评估了分馏和季节性流动性变化的Ga和In的系统受酸性热沃茨。这是通过使用PHREEQC算法进行热力学计算和评估嗜酸性铁氧化细菌的活性来实现的。日本中部群马县草津温泉沃茨的pH值在加入石灰悬浮液后迅速升高。在pH值突然升高后，Ga和In的自由离子及其与Cl-和SO 42-的络合物仅以可忽略的量存在，大部分溶解的Ga和In通过吸附到悬浮的水合氧化铁（HFO）上而被去除。然后，这些HFO被输送到人工湖，而不会沿河流沿着发生明显的沉积。随后，悬浮的HFO沉降出来，并被添加到沉积物中，而Ga和In之间没有显著的分馏。日本东北部秋田县的多摩川温泉沃茨也用石灰处理。然而，完全中和需要与一些支流混合，导致下游pH值逐渐增加。溶解的镓，在一般情况下，吸附在上游地区的HFO，导致广泛的分散在整个流域的镓。相比之下，In主要以Cl−络合物的形式被输送到湖泊入口，而不会沿着河流被显著去除，大部分沉淀在人工湖中，其中Cl−浓度太低，无法与In形成稳定的络合物，因此，溶解的In被HFO吸附。因此，在有效地集中在下游湖底沉积物，而镓分散沿着。Ga流动性的季节性变化，在玉川领域之间的融雪和低流量的季节主要由pH值控制，因为这些金属的水解反应，这是相关的吸附反应，往往发生在上游地区的融雪季节。然而，在较温暖的条件下，由于嗜酸性铁氧化细菌的活性，优选发生HFO形成。因此，在类似的pH值变化下，溶解的Ga在温暖的季节被HFO更有效地去除。相反，由于HFO在低流量季节大量形成，即使在较冷的条件下，在In水解反应开始发生之前，In的流动性受水温和细菌活性的影响较小。
This work assessed both the fractionation and the seasonal mobility variations of Ga and In in systems impacted by acidic thermal waters. This was accomplished by performing thermodynamic calculations using the PHREEQC algorithm and by assessing the activity of acidophilic iron-oxidizing bacteria. The pH of the Kusatsu thermal waters in Gunma Prefecture, central Japan, is rapidly increased following the addition of a lime suspension. After an abrupt pH increase, under which conditions free ions of Ga and In and their complexes with Cl−and SO42−exist only in negligible quantities, the majority of dissolved Ga and In is removed by sorption onto suspended hydrous ferric oxides (HFOs). These HFOs are then transported to an artificial lake without significant sedimentation along the river. Subsequently, the suspended HFOs settle out and are added to sediments without significant fractionation between Ga and In. The Tamagawa thermal waters in Akita Prefecture, northeast Japan, are also treated with lime. However, complete neutralization requires mixing with some tributary streams, leading to a gradual downstream increase in pH. Dissolved Ga is, in general, sorbed by HFOs in upstream areas, leading to wide dispersal of Ga across the entire watershed. In comparison, In is transported to the lake inlet predominantly as a Cl−complex species without significant removal along the river, with the majority being precipitated in an artificial lake, where Cl−concentrations are too low to form stable complex species with In, and thus, dissolved In is sorbed by HFOs. As a result, In is effectively concentrated within downstream lakebed sediments, whereas Ga is dispersed along the river. Seasonal variations in Ga mobility within the Tamagawa field between snowmelt and low-flow seasons are primarily controlled by pH, because hydrolysis reactions of these metals, which are related to sorption reactions, tend to occur in the upstream regions in the snowmelt season. However, under warmer conditions, HFO formation preferably occurs due to the activity of acidophilic iron-oxidizing bacteria. Thus, under similar pH variations, dissolved Ga is more effectively removed by HFOs during warmer seasons. On the contrary, because HFOs are abundantly formed in low-flow season, even under colder conditions, before In hydrolysis reaction starts to occur, In mobility is less affected by water temperature and then bacterial activity.