Role of competing ions in the mobilization of arsenic in groundwater of Bengal Basin: Insight from surface complexation modeling
Role of competing ions in the mobilization of arsenic in groundwater of Bengal Basin: Insight from surface complexation modeling
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DOI：
10.1016/j.watres.2014.02.002
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发表时间：
2014-05-15
期刊：
影响因子：
12.8
通讯作者：
Bhattacharya, Prosun
中科院分区：
文献类型：
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作者：
Biswas, Ashis;Gustafsson, Jon Petter;Bhattacharya, Prosun
本研究评估的作用，竞争离子在动员砷（As）的表面络合模拟的时间变化的砷在地下水中。两种不同的表面络合模型（SCM），开发的水铁矿和针铁矿的潜在用途，已被探索占的时间变化的As（III）和As（V）的浓度，监测在孟加拉盆地浅层地下水超过20个月。的SCM的水铁矿出现作为更好的预测所观察到的变化，在两个As（III）和As（V）的浓度在研究地点。结果表明，在Fe（OH）2吸附As（III）和As（V）的竞争离子中，PO 43-是Fe（OH）2吸附As（III）和As（V）的主要竞争离子，竞争能力的大小顺序为PO 43- >> Fe（II）> H4 SiO 4 = HCO-（3.）研究还表明，pH值的微小变化也会对As（III）和As（V）在含水层中的流动性产生重大影响。pH值的降低会增加As（III）的浓度，而降低As（V）的浓度，反之亦然。本研究表明，还原溶解的Fe羟基氧化物单独不能解释所观察到的高砷浓度的孟加拉盆地的地下水。这项研究支持的观点，还原溶解的Fe羟基氧化物，然后与含水层沉积物的竞争吸附反应是负责地下水富集的过程。(C)2014爱思唯尔有限公司版权所有。
This study assesses the role of competing ions in the mobilization of arsenic (As) by surface complexation modeling of the temporal variability of As in groundwater. The potential use of two different surface complexation models (SCMs), developed for ferrihydrite and goethite, has been explored to account for the temporal variation of As(III) and As(V) concentration, monitored in shallow groundwater of Bengal Basin over a period of 20 months. The SCM for ferrihydrite appears as the better predictor of the observed variation in both As(III) and As(V) concentrations in the study sites. It is estimated that among the competing ions, PO43- is the major competitor of As(III) and As(V) adsorption onto Fe oxyhydroxide, and the competition ability decreases in the order PO43- >> Fe(II) > H4SiO4 = HCO- (3.) It is further revealed that a small change in pH can also have a significant effect on the mobility of As(III) and As(V) in the aquifers. A decrease in pH increases the concentration of As(III), whereas it decreases the As(V) concentration and vice versa. The present study suggests that the reductive dissolution of Fe oxyhydroxide alone cannot explain the observed high As concentration in groundwater of the Bengal Basin. This study supports the view that the reductive dissolution of Fe oxyhydroxide followed by competitive sorption reactions with the aquifer sediment is the processes responsible for As enrichment in groundwater. (C) 2014 Elsevier Ltd. All rights reserved.