Silicic acid competes for dimethylarsinic acid (DMA) immobilization by the iron hydroxide plaque mineral goethite.
Silicic acid competes for dimethylarsinic acid (DMA) immobilization by the iron hydroxide plaque mineral goethite.
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硅酸与氢氧化铁斑块矿物针铁矿竞争固定二甲基胂酸 (DMA)
DOI：
10.1016/j.scitotenv.2014.11.093
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Daus B.
中科院分区：
文献类型：
--
作者：
Kersten M;Daus B.
使用表面络合建模方法来扩展有关在强吸附剂存在的情况下影响土壤根际二甲氧基硅酸（DMA）有效性的过程的知识，例如水稻根系上的铁斑块。已发表的光谱和分子模型信息表明，有机砷剂与铁氢氧化物形成双齿双核球内表面配合物，类似于无机砷氧阴离子。然而，由于无处不在的硅酸氧阴离子也形成了相同的双齿双核表面配合物，我们的假设是它可能对土壤中铁氢氧化物对DMA的吸附有影响。我们的实验批平衡数据表明，DMA在酸性pH范围内被强吸附，在DMA酸度常数（pKa= 6.3）和针铁矿吸附剂零电荷点（pHpzc= 8.6）之间的环中性pH区有陡峭的吸附边。选择1-pKCD-MUSIC表面络合模型拟合实验吸附与pH值的关系。用针铁矿吸附剂对硅酸批平衡数据进行了同样的处理。然后将单个DMA和硅酸吸附的模型参数合并到一个CD-MUSIC模型中，以预测二元DMA + Si的吸附行为。因此，该模型预测，在pH为6的条件下，硅酸（500 μM）对DMA具有很强的竞争能力，后者的动员率高达60%。该模型结果可以通过零可调参数的实验批平衡数据进行验证。本文还讨论了二氧化硅施肥后水稻籽粒中DMA比例增加的原因之一，即DMA与硅酸之间的拮抗关系。
A surface complexation modeling approach was used to extend the knowledge about processes that affect the availability of dimethylarsinic acid (DMA) in the soil rhizosphere in presence of a strong sorbent, e.g., Fe plaques on rice roots. Published spectroscopic and molecular modeling information suggest for the organoarsenical agent to form bidentate-binuclear inner-sphere surface complexes with Fe hydroxides similar to the inorganic As oxyanions. However, since also the ubiquitous silicic acid oxyanion form the same bidentate binuclear surface complexes, our hypothesis was that it may have an effect on the adsorption of DMA by Fe hydroxides in soil. Our experimental batch equilibrium data show that DMA is strongly adsorbed in the acidic pH range, with a steep adsorption edge in the circumneutral pH region between the DMA acidity constant (pKa= 6.3) and the point of zero charge value of the goethite adsorbent (pHpzc= 8.6). A 1-pKCD-MUSIC surface complexation model was chosen to fit the experimental adsorption vs. pH data. The same was done for silicic acid batch equilibrium data with our goethite adsorbent. Both model parameters for individual DMA and silicic acid adsorption were then merged into one CD-MUSIC model to predict the binary DMA + Si adsorption behavior. Silicic acid (500 μM) was thus predicted by the model to strongly compete for DMA with up to 60% mobilization of the latter at a pH 6. This model result could be verified subsequently by experimental batch equilibrium data with zero adjustable parameters. The thus quantified antagonistic relation between DMA and silicic acid is discussed as one of factors to explain the increase of the DMA proportion in rice grains as observed upon silica fertilization of rice fields.
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影响因子：
11.4
作者：
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通讯作者：
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影响因子：
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影响因子：
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作者：
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合成针铁矿的形态和表面异质性。
影响因子：
9.9
作者：
B. Prélot;F. Villieras;M. Pelletier;G. Gérard;F. Gaboriaud;J. Ehrhardt;J. Perrone;M. Fédoroff;J. Jeanjean;G. Lefèvre;L. Mazerolles;J. Pastol;J. Rouchaud;C. Lindecker
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C. Lindecker