DFT simulation of the adsorption of sodium silicate species on kaolinite surfaces
DFT simulation of the adsorption of sodium silicate species on kaolinite surfaces
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DOI：
10.1016/j.apsusc.2016.02.179
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发表时间：
2016-05-01
影响因子：
6.7
通讯作者：
Chen, Jianhua
中科院分区：
文献类型：
--
作者：
Han, Yonghua;Liu, Wenli;Chen, Jianhua
采用密度泛函理论（DFT）研究了Si（OH）4和SiO（OH）3（-）在高岭石表面的吸附，探讨了硅酸钠在高岭石表面的分散机理。计算结果表明，Si（OH）（4）和SiO（OH）（3）（-）主要吸附在高岭石Al端的（001）表面上。Si（OH）（4）和SiO（OH）（3）（-）都通过O-2 p轨道和H-1 s轨道的杂化与Al封端的表面成键。SiO（OH）（3）（-）中未键合的O原子具有显著的活性。SiO（OH）3（-）阴离子可以增加更多的电子，与Al表面形成更强的静电相互作用。SiO（OH）（3）（-）的吸附比Si（OH）（4）的吸附更稳定。高岭石吸附硅酸钠后，表面亲水性增强，带负电荷增加。因此，硅酸盐物种的吸附使高岭石微粒更容易分散在水溶液中。(C)2016爱思唯尔B. V.保留所有权利。
The adsorption of Si(OH)(4) molecules and the SiO(OH)(3)(-) anion on kaolinite surfaces was studied using density functional theory (DFT) calculations to investigate the dispersion mechanism of sodium silicate on kaolinite particles. The calculated results demonstrate that Si(OH)(4) and SiO(OH)(3)(-) primarily adsorb on kaolinite Al-terminated (001) surfaces. Both Si(OH)(4) and SiO(OH)(3)(-) bond with the Al-terminated surface by hybridization of the O-2p orbital and H-1s orbital. The unbonded O atom of SiO(OH)(3)(-) is notably active. The SiO(OH)(3)(-) anion can add more electrons and form a stronger electrostatic interaction with the Al surface. The adsorption of SiO(OH)(3)(-) is more stable than the adsorption of Si(OH)(4). After adsorption of sodium silicate, the surfaces of kaolinite can become more hydrophilic and carry more negative charge. Therefore, the adsorption of silicate species makes the fine particles of kaolinite disperse in aqueous solution more easily. (C) 2016 Elsevier B.V. All rights reserved.