The role of hydrous ferric oxide precipitation in the fractionation of arsenic, gallium, and indium during the neutralization of acidic hot spring water by river water in the Tama River watershed, Japan
The role of hydrous ferric oxide precipitation in the fractionation of arsenic, gallium, and indium during the neutralization of acidic hot spring water by river water in the Tama River watershed, Japan
复制标题
日本多摩川流域河水中和酸性温泉水过程中水合三氧化二铁沉淀在砷、镓和铟分馏中的作用
DOI：
10.1016/j.gca.2012.03.009
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Noriyoshi Tsuchiya
中科院分区：
文献类型：
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作者：
Yasumasa Ogawa;Daizo Ishiyama;Naotatsu Shikazono;Kenta Iwane;Masahiro Kajiwara;Noriyoshi Tsuchiya
小吹温泉是日本北方秋田县玉川温泉中最大、酸性最强的温泉，它排出的水约为200毫升。9000 L/min的富氯酸性水（pH 1.2），含有高浓度的As和稀有金属，如Ga和In。本文旨在量化这些元素的流动性的季节性变化，在涩黑和多摩河，这是美联储的热沃茨的小吹，所造成的吸附到水合氧化铁（HFO）。季节性观察揭示了以下关系与HFO去除As：（a）Fe 2+的氧化主要是由pH值和水温控制，并在酸性较低和较温暖的条件下进行得更快;（B）HFO的形成主要是由pH值控制;和（c）溶解的砷酸盐的去除是直接相关的HFO存在的量。因此，在寒冷和较低pH期间，氧化为Fe 3+较慢，并且HFO的量太小而不能有效地去除溶解的砷酸盐。因此，相当数量的溶解砷酸盐和Fe 2+留在河水中。相比之下，当HFO生产从Fe 3+增加，溶解的砷酸盐被删除在温暖和酸性较低的时期，只有少量的溶解的亚砷酸盐和Fe 2+留在河水中。Ga和In的地球化学行为主要受pH值的控制，当HFO的生成受pH值小于3.5的限制时，Ga的行为主要受HFO量的控制。镓往往被吸附在更酸性的条件下比在。由于吸附行为的差异，Ga，As和In在沉降过程中被分馏。在上游，砷酸盐和溶解镓吸附到HFO，并广泛分布在整个流域。相反，溶解的In被下游的HFO去除。因此，In相对集中在下游湖底，而不像As和Ga，目前正在积累富In矿床。
The Obuki spring is the largest and most acidic of the Tamagawa hot springs (Akita Prefecture, northern Japan), and it discharges ca. 9000L/min of chloride-rich acidic water (pH 1.2) that contains high concentrations of both As and rare metals such as Ga and In. This paper aims to quantify seasonal variations in the mobility of these elements in the Shibukuro and Tama rivers, which are fed by the thermal waters of the Obuki spring, caused by sorption onto hydrous ferric oxide (HFO). Seasonal observations revealed the following relationships with respect to As removal by HFO: (a) the oxidation of Fe2+is predominantly controlled by both pH and water temperature, and progresses more quickly in less acidic and warmer conditions; (b) HFO formation was predominantly controlled by pH; and (c) the removal of dissolved arsenate is directly related to the amount of HFO present. Consequently, the oxidation to Fe3+was slower during periods of cold and lower pH, and the amount of HFO was too small to remove the dissolved arsenate effectively. Consequently, considerable amounts of dissolved arsenate and Fe2+remained in river water. In contrast, when HFO production from Fe3+increased, and dissolved arsenate was removed during warmer and less acidic periods, only small amounts of dissolved arsenite and Fe2+remained in the river water. The geochemical behavior of Ga and In was essentially controlled by pH; however, when HFO production was limited by a pH of less than 3.5, Ga behavior was controlled mainly by the amount of HFO. Gallium tended to be sorbed under more acidic conditions than was In. Due to differences in sorption behavior, Ga, As, and In were fractionated during sedimentation. In the upstream reaches, arsenate and dissolved Ga sorbed onto HFO, and were widely distributed across the watershed. Conversely, dissolved In was removed by HFO downstream. As a result, In is relatively concentrated on the downstream lakebed, unlike As and Ga, and In-rich mineral deposits are accumulating at present.