Water Contact Angle Dependence with Hydroxyl Functional Groups on Silica Surfaces under CO2 Sequestration Conditions
Water Contact Angle Dependence with Hydroxyl Functional Groups on Silica Surfaces under CO2 Sequestration Conditions
复制标题
CO2 封存条件下二氧化硅表面羟基官能团对水接触角的依赖性
DOI：
10.1021/acs.est.5b03646
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发表时间：
2015-12-15
影响因子：
11.4
通讯作者：
Song, Yongchen
中科院分区：
文献类型：
--
作者：
Chen, Cong;Zhang, Ning;Song, Yongchen
由于超临界CO2、盐水和二氧化硅之间的反应，CO2封存条件下二氧化硅表面上的官能团是复杂的。分子动力学模拟已经进行了研究羟基官能团对润湿性的影响。已经发现，润湿性表现出强烈的依赖于二氧化硅表面上的官能团：硅烷醇数密度，空间分布，和去质子化/质子化程度。对于具有晶体结构（Q（3），Q（3）/Q（4），Q（4））的中性SiO2表面，在10.5MPa和318 K下，随着硅醇数密度的降低，接触角从33.5 °增加到146.7 °。当Q（3）表面变为无定形结构时，水接触角增加20度。当Q（3）表面上9%的硅醇基团被去质子化时，水接触角减小约12度。当去质子化度增加到50%时，水接触角减小到0。用二氧化硅表面官能团对润湿性的依赖性来分析文献中接触角测量的模糊性。CO2封存条件下二氧化硅表面的组成是复杂的，本研究的结果有助于更好地理解CO2/盐水/二氧化硅体系的润湿性。
Functional groups on silica surfaces under CO2 sequestration conditions are complex due to reactions among supercritical CO2, brine and silica. Molecular dynamics simulations have been performed to investigate the effects of hydroxyl functional groups on wettability. It has been found that wettability shows a strong dependence on functional groups on silica surfaces: silanol number density, space distribution, and deprotonation/protonation degree. For neutral silica surfaces with crystalline structure (Q(3), Q(3)/Q(4), Q(4)), as silanol number density decreases, contact angle increases from 33.5 degrees to 146.7 degrees at 10.5 MPa and 318 K. When Q(3) surface changes to an amorphous structure, water contact angle increases 20 degrees. Water contact angle decreases about 12 degrees when 9% of silanol groups on Q(3), surface are deprotonated. When the deprotonation degree increases to 50%, water contact angle decreases to 0. The dependence of wettability on silica surface functional groups was used to analyze contact angle measurement ambiguity in literature. The composition of silica surfaces is complicated under CO2 sequestration conditions, the results found in this study may help to better understand wettability of CO2/brine/silica system.