Liu Huiquan, Shi Changrui, Wang Shuai, Zhang Lunxiang, Zhao Jiafei, Yang Mingjun, Chen Cong, Song Yongchen, Ling Zheng
Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, School of Energy & Power Engineering, Dalian University of Technology, Dalian 116024, China.
Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, School of Energy & Power Engineering, Dalian University of Technology, Dalian 116024, China; Ningbo Institute of Dalian University of Technology, Ningbo, 315016, China.
J Colloid Interface Sci. 2023 Jul;641:812-819. doi: 10.1016/j.jcis.2023.03.118. Epub 2023 Mar 21.
Carbon dioxide (CO) reduction is an urgent challenge worldwide due to the dramatically increased CO concentration and concomitant environmental problems. Geological CO storage in gas hydrate in marine sediment is a promising and attractive way to mitigate CO emissions owning to its huge storage capability and safety. However, the sluggish kinetics and unclear enhancing mechanisms of CO hydrate formation limit the practical application of hydrate-based CO storage technologies. Here, we used vermiculite nanoflakes (VMNs) and methionine (Met) to investigate the synergistic promotion of natural clay surface and organic matter on CO hydrate formation kinetics. Induction time and t in VMNs dispersion with Met were shorter by one to two orders of magnitude than Met solution and VMNs dispersion. Besides, CO hydrate formation kinetics showed significant concentration-dependence on both Met and VMNs. The side chains of Met can promote CO hydrate formation by inducing water molecules to form a clathrate-like structure. However, when Met concentration exceeded 3.0 mg/mL, the critical amount of ammonium ions from dissociated Met distorted the ordered structure of water molecules, inhibiting CO hydrate formation. Negatively charged VMNs can attenuate this inhibition by adsorbing ammonium ions in VMNs dispersion. This work sheds light on the formation mechanism of CO hydrate in the presence of clay and organic matter which are the indispensable constituents of marine sediments, also contributes to the practical application of hydrate-based CO storage technologies.
由于二氧化碳（CO₂）浓度急剧增加以及随之而来的环境问题，减少CO₂排放是全球面临的一项紧迫挑战。海洋沉积物中天然气水合物的地质CO₂储存因其巨大的储存能力和安全性，是一种有前景且有吸引力的减少CO₂排放的方式。然而，CO₂水合物形成的动力学缓慢且增强机制不明，限制了基于水合物的CO₂储存技术的实际应用。在此，我们使用蛭石纳米片（VMNs）和蛋氨酸（Met）来研究天然粘土表面和有机物对CO₂水合物形成动力学的协同促进作用。与Met溶液和VMNs分散液相比，在含有Met的VMNs分散液中，诱导时间和t缩短了一到两个数量级。此外，CO₂水合物形成动力学对Met和VMNs均表现出显著的浓度依赖性。Met的侧链可通过诱导水分子形成笼形结构来促进CO₂水合物的形成。然而，当Met浓度超过3.0 mg/mL时，解离出的Met产生的铵离子临界量会破坏水分子的有序结构，抑制CO₂水合物的形成。带负电荷的VMNs可通过吸附VMNs分散液中的铵离子来减弱这种抑制作用。这项工作揭示了在粘土和有机物存在下CO₂水合物的形成机制，而粘土和有机物是海洋沉积物中不可或缺的成分，也有助于基于水合物的CO₂储存技术的实际应用。
