Department of Earth and Environmental Sciences, University of Illinois at Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States.
Environ Sci Technol. 2012 May 15;46(10):5623-30. doi: 10.1021/es3005865. Epub 2012 Apr 23.
Powder X-ray diffraction shows that K- and Ca-exchanged montmorillonites swell upon interacting with CO(2) at ambient temperatures, depending on their initial hydration state. K-exchanged montmorillonite swells rapidly to a maximum d(001) of ∼12.2 Å. In contrast, Ca-exchanged montmorillonite swells more slowly, but reaches a maximum d(001) of ∼15.1 Å. Reaction kinetics differ significantly between the K- and Ca-exchanged montmorillonite complexes. Expansion of K-exchanged montmorillonite samples was rapid, occurring on time scales of tens of minutes or less. The Ca-exchanged montmorillonite samples continued to expand over periods up to 42 h. Aging of both K- and Ca-exchanged montmorillonite complexes at elevated CO(2) pressure for 1-2 days resulted in greater stability when CO(2) pressure was released. The observed intercalation reactions have important consequences for carbon sequestration: (1) CO(2) absorption by swelling clays may represent a significant pathway for storage of CO(2). (2) The swelling of smectites under CO(2) pressure may have a significant impact on the permeability of caprock formations.
粉末 X 射线衍射表明，在环境温度下，K 和 Ca 交换蒙脱石与 CO(2)相互作用时会发生膨胀，这取决于它们的初始水合状态。K 交换蒙脱石迅速膨胀到最大 d(001)约 12.2 Å。相比之下，Ca 交换蒙脱石膨胀较慢，但达到最大 d(001)约 15.1 Å。K 和 Ca 交换蒙脱石复合物之间的反应动力学有显著差异。K 交换蒙脱石样品的膨胀速度很快，在几十分钟或更短的时间内发生。Ca 交换蒙脱石样品在长达 42 小时的时间内继续膨胀。在升高的 CO(2)压力下，K 和 Ca 交换蒙脱石复合物老化 1-2 天，当 CO(2)压力释放时，稳定性更高。观察到的插层反应对碳封存有重要影响：(1) 膨胀粘土对 CO(2)的吸收可能代表 CO(2)储存的重要途径。(2) 在 CO(2)压力下蒙脱石的膨胀可能对盖层形成的渗透率有重大影响。
