Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
Environ Sci Technol. 2011 Feb 15;45(4):1737-43. doi: 10.1021/es1034975. Epub 2011 Jan 11.
To ensure the viability of geologic CO2 sequestration (GCS), we need a holistic understanding of reactions at supercritical CO2 (scCO2)-saline water-rock interfaces and the environmental factors affecting these interactions. This research investigated the effects of salinity and the extent of water on the dissolution and surface morphological changes of phlogopite [KMg2.87Si3.07Al1.23O10(F,OH)2], a model clay mineral in potential GCS sites. Salinity enhanced the dissolution of phlogopite and affected the location, shape, size, and phase of secondary minerals. In low salinity solutions, nanoscale particles of secondary minerals formed much faster, and there were more nanoparticles than in high salinity solutions. The effect of water extent was investigated by comparing scCO2-H2O(g)-phlogopite and scCO2-H2O(l)-phlogopite interactions. Experimental results suggested that the presence of a thin water film adsorbed on the phlogopite surface caused the formation of dissolution pits and a surface coating of secondary mineral phases that could change the physical properties of rocks. These results provide new information for understanding reactions at scCO2-saline water-rock interfaces in deep saline aquifers and will help design secure and environmentally sustainable CO2 sequestration projects.
为了确保地质封存二氧化碳（GCS）的可行性，我们需要全面了解超临界 CO2（scCO2）-盐水-岩石界面的反应以及影响这些相互作用的环境因素。本研究调查了盐度和含水量对潜在 GCS 地点中模型粘土矿物白云母 [KMg2.87Si3.07Al1.23O10(F,OH)2] 的溶解和表面形貌变化的影响。盐度增强了白云母的溶解，并影响了次生矿物的位置、形状、大小和相。在低盐度溶液中，次生矿物的纳米级颗粒形成得更快，纳米颗粒的数量也比在高盐度溶液中多。通过比较 scCO2-H2O(g)-白云母和 scCO2-H2O(l)-白云母的相互作用，研究了含水量的影响。实验结果表明，吸附在白云母表面的薄水膜的存在导致了溶解坑的形成和次生矿物相的表面覆盖，这可能改变岩石的物理性质。这些结果为深入了解深部咸水含水层中 scCO2-盐水-岩石界面的反应提供了新的信息，并将有助于设计安全且环境可持续的 CO2 封存项目。
