On the Acid-Base Chemistry of Permanently Charged Minerals
On the Acid-Base Chemistry of Permanently Charged Minerals
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DOI：
10.1021/es9802899
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发表时间：
1998-08
影响因子：
11.4
通讯作者：
A. Kraepiel;K. Keller;F. Morel
中科院分区：
文献类型：
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作者：
A. Kraepiel;K. Keller;F. Morel
氧化物的酸碱性质可以用表面络合模型很好地描述，该模型将氧化物表面酸碱反应的热力学描述与固溶体界面静电的双层模型叠加在一起。然而，到目前为止，这个模型还没有扩展到包括永久电荷的影响，例如，从粘土中的同构取代。与氧化物相反，具有永久电荷的固体在低pH值下通常表现出随着离子强度的降低而增加的质子化程度。它们还表现出随着离子强度的降低而增加的零质子条件（ZPC）。在这里，我们研究了固体的非pH依赖性电荷对其酸碱性质的影响。我们考虑两种简单的情况：模型1，其中所有的酸碱基团和pH无关的电荷分布在不可穿透的固体的表面，在与溶液的界面处;模型2，其中固体是多孔的（即，可被水和电穿透
The acid−base properties of oxides are well described by the surface complexation model, which superposes a thermodynamic description of acid−base reactions at the oxide surface with a double-layer model of the electrostatics at the solid−solution interface. So far, however, this model has not been extended to include the effects of permanent charges such as result, for example, from isomorphic substitution in clays. Contrary to oxides, solids with permanent charge often exhibit an increasing degree of protonation with decreasing ionic strength at low pH. They also show an increase in their zero proton condition (ZPC) with decreasing ionic strength. Here we examine the influence of the pH-independent charge of a solid on its acid−base properties. We consider two simple cases: model 1 in which all the acid−base groups and pH-independent charges are distributed at the surface of a nonpenetrable solid, at the interface with the solution; Model 2 in which the solid is porous (i.e., penetrable by water and el...