Key Laboratory of Ocean Energy Utilization and Energy Conservation of the Ministry of Education, Dalian University of Technology, Dalian 116024, China.
J Phys Chem Lett. 2021 Apr 8;12(13):3464-3467. doi: 10.1021/acs.jpclett.1c00010. Epub 2021 Apr 1.
A deeper understanding of the kinetics of CO hydrate formation in the complicated natural environment is required for its enhanced sequestration. Here we found that the organics-coated nanoclays enriched in the natural sediments could contribute to a 92% decline of the induction time of hydrate formation. This can be ascribed to the negative charges carried by the organics and the resulting ordered arrangement of the surrounding water molecules. It was, for the first time, proposed that the abundant functional groups from the coating organics could function as a protecting crust enabling the system more resistant to the acidification potentially upon the CO sequestration; besides, the negative charges could help prevent the deposition of the nanoclays via interparticle repulsive forces. These would consequently secure their sustainable promoting effect on hydrate formation. The findings suggest the deposits of gas hydrate a kinetically promising geological setting for the CO sequestration via forming hydrates.
为了增强 CO2 的封存效果，需要更深入地了解其在复杂自然环境中的水合物形成动力学。在这里，我们发现富含天然沉积物的有机包覆纳米粘土可以将水合物形成的诱导时间减少 92%。这可以归因于有机物质所携带的负电荷以及周围水分子的有序排列。这是首次提出，涂层有机物质中丰富的官能团可以作为保护壳，使系统在 CO2 捕集时更能抵抗潜在的酸化；此外，负电荷可以通过颗粒间的排斥力来防止纳米粘土的沉积。这将有助于确保它们对水合物形成的持续促进作用。这些发现表明，天然气水合物的沉积物是通过形成水合物来封存 CO2 的一种在动力学上很有前途的地质环境。
