Molecular Simulation Study of CO 2 Adsorption and Sequestration on Clay Minerals under Geological Conditions

High Resolution Image Download MS PowerPoint Slide Geological utilization and sequestration of CO 2 are considered among the most effective methods for reducing carbon emissions. Clay minerals, as dominant diagenetic components in sedimentary formations, play a crucial role in CO 2 geological sequestration owing to their large surface area and strong adsorption capacity. In this study, the adsorption and sequestration mechanisms of CO 2 on typical clay minerals, including illite and kaolinite, were systematically investigated under geological temperature and pressure conditions representative of the eastern Junggar Basin using grand canonical Monte Carlo and molecular dynamics simulations. The results demonstrate that CO 2 adsorption capacity is governed by the coupled effects of mineral type, pore size, temperature, and pressure. Illite exhibits approximately 1.4 times higher CO 2 storage capacity than kaolinite, attributed to its stronger thermodynamic affinity and higher adsorption heat. Elevated temperature reduces CO 2 adsorption, whereas increased pressure promotes it. In micropores smaller than 2 nm, confinement effects dominate and yield stable monolayer adsorption, while in mesopores, multilayer adsorption and coexistence of adsorbed and free CO 2 phases occur as the pore size increases. The adsorbed phase proportion is consistently higher in illite, implying more stable and efficient CO 2 trapping. These findings provide molecular-level insights into CO 2 -clay mineral interactions and establish a theoretical foundation for evaluating storage capacity, trapping stability, and caprock integrity, offering practical guidance for the safe and efficient implementation of CO 2 geological sequestration projects in the eastern Junggar Basin, China.