Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Langmuir. 2012 May 8;28(18):7125-8. doi: 10.1021/la301136w. Epub 2012 Apr 27.
The interaction of anhydrous supercritical CO(2) (scCO(2)) with both kaolinite and ~1W (i.e., close to but less than one layer of hydration) calcium-saturated montmorillonite was investigated under conditions relevant to geologic carbon sequestration (50 °C and 90 bar). The CO(2) molecular environment was probed in situ using a combination of three novel high-pressure techniques: X-ray diffraction, magic angle spinning nuclear magnetic resonance spectroscopy, and attenuated total reflection infrared spectroscopy. We report the first direct evidence that the expansion of montmorillonite under scCO(2) conditions is due to CO(2) migration into the interlayer. Intercalated CO(2) molecules are rotationally constrained and do not appear to react with waters to form bicarbonate or carbonic acid. In contrast, CO(2) does not intercalate into kaolinite. The findings show that predicting the seal integrity of caprock will have complex dependence on clay mineralogy and hydration state.
在与地质碳封存相关的条件下（50°C 和 90 巴），研究了无水超临界 CO2（scCO2）与高岭石和~1W（即接近但不到一层水合的）钙饱和蒙脱石之间的相互作用。使用三种新型高压技术的组合：X 射线衍射、魔角旋转核磁共振波谱和衰减全反射红外光谱，原位探测 CO2 分子环境。我们首次直接证明，蒙脱石在 scCO2 条件下的膨胀是由于 CO2 迁移到层间。插层 CO2 分子受到旋转约束，似乎不会与水反应形成碳酸氢盐或碳酸。相比之下，CO2 不会插入高岭石。研究结果表明，预测盖层的密封完整性将复杂地取决于粘土矿物学和水合状态。
