Arsenic-bicarbonate interaction on goethite particles
Arsenic-bicarbonate interaction on goethite particles
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DOI：
10.1021/es063087i
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发表时间：
2007-08-15
影响因子：
11.4
通讯作者：
Van Riemsdijk, Willem H.
中科院分区：
文献类型：
--
作者：
Stachowicz, Monika;Hiemstra, Tjisse;Van Riemsdijk, Willem H.
本文研究了针铁矿体系中As(V)和As(Ill)与HCO3的相互作用，在与现场条件相关的pH和As浓度范围内。我们的研究表明，溶解的小苏打可能是ASM和As(III)的竞争对手。在我们的封闭体系中，碳酸氢盐的最大影响发生在最低的实验pH值(pH-6.5)，这与碳酸盐吸附过程的pH依赖性有关。实验数据用电荷分布(CD)模型进行了模拟。分别用HCO3、As(III)和As(V)的“单离子”吸附数据对针铁矿的CD模型进行了参数化处理。可以很好地预测HC03对As(III)和As(V)释放的竞争作用。模型的应用表明，含水物质的天然As负荷比单独基于As-HCO3竞争的As负荷小1-2个数量级。这表明，另一个非常突出的竞争对手，如磷酸盐和天然有机物，将对自然系统中砷的控制做出强有力的贡献。
The As(V) and As(Ill) interaction with HCO3 has been studied for goethite systems using a pH and As concentration range that is relevant for field situations. Our study shows that dissolved bicarbonate may act as a competitor for both AsM and As(III). In our closed systems, the largesteffect of bicarbonate occurs atthe lowest experimental pH values (pH -6.5), which is related to the pH dependency of the carbonate adsorption process. The experimental data have been modeled with the charge distribution (CD) model. The CD model was separately parametrized for goethite with "single ion" adsorption data of HCO3, As(III), and As(V). The competitive effect of HC03 on the As(III) and As(V) release could be predicted well. Application of the model shows that the natural As loading of aquifer materials (- 1 -2 orders of magnitude smaller than the As loading based on the competition of As-HCO3 alone. It indicates that another, very prominent competitor, like phosphate and natural organic matter, will strongly contribute to the control of As in natural systems.