Modelling how incorporation of divalent cations affects calcite wettability-implications for biomineralisation and oil recovery.
Modelling how incorporation of divalent cations affects calcite wettability-implications for biomineralisation and oil recovery.
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DOI：
10.1038/srep28854
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发表时间：
2016-06-29
影响因子：
4.6
通讯作者：
Stipp SL
中科院分区：
文献类型：
--
作者：
Andersson MP;Dideriksen K;Sakuma H;Stipp SL
利用密度泛函理论和地球化学形态模型，我们预测了当二价阳离子取代方解石表面时固液界面能如何变化。对润湿性的影响可能是巨大的。微量金属的吸收会影响有机化合物的吸附，例如影响生物体控制晶体生长的能力以及我们预测孔隙表面润湿性的能力。润湿性影响有机相从表面去除的容易程度，无论是来自受污染土壤的有机化合物还是来自储层的原油。在我们的模拟中，过渡金属以放热方式取代方解石，并且比本体更有利地取代方解石的表面位置，这意味着表面性质受到比本体实验结果暗示的更强烈的影响。由于二价阳离子取代，方解石-流体界面能显着改变，足以改变宏观接触角数十度。 Sr、Ba 和 Pb 的取代使表面更加疏水。随着镁和过渡金属的取代，方解石变得更加亲水，削弱了有机化合物的吸附。对于生物矿化，这提供了打开和关闭有机晶体生长抑制剂活性的开关，从而控制相关矿物相的形状。
Using density functional theory and geochemical speciation modelling, we predicted how solid-fluid interfacial energy is changed, when divalent cations substitute into a calcite surface. The effect on wettability can be dramatic. Trace metal uptake can impact organic compound adsorption, with effects for example, on the ability of organisms to control crystal growth and our ability to predict the wettability of pore surfaces. Wettability influences how easily an organic phase can be removed from a surface, either organic compounds from contaminated soil or crude oil from a reservoir. In our simulations, transition metals substituted exothermically into calcite and more favourably into sites at the surface than in the bulk, meaning that surface properties are more strongly affected than results from bulk experiments imply. As a result of divalent cation substitution, calcite-fluid interfacial energy is significantly altered, enough to change macroscopic contact angle by tens of degrees. Substitution of Sr, Ba and Pb makes surfaces more hydrophobic. With substitution of Mg and the transition metals, calcite becomes more hydrophilic, weakening organic compound adsorption. For biomineralisation, this provides a switch for turning on and off the activity of organic crystal growth inhibitors, thereby controlling the shape of the associated mineral phase.