Electric Fields Assisted ZIF-8 Adsorption Hydration Methane Storage and Release: A Molecular Insight

The ZIF-8 adsorption-hydration method is regarded as a highly promising technology for methane storage. However, the high temperatures required for ZIF-8 desorption and the slow growth rate of methane hydrate has become unsatisfactory in current production. In this study, the behavior of ZIF-8 adsorption-hydration for methane storage and release under a cosine-oscillating electric field was systematically investigated via molecular dynamics simulations. The results indicate that an electric field of 1 V/nm at 8 THz can effectively promote methane desorption from ZIF-8. Under 273 K and 0.1 MPa, the residual fraction of methane in ZIF-8 after desorption decreased from 77.7% to 5.4%. In addition, the electric field influences hydrate growth by modulating hydrogen bonding between water molecules, and, at each field strength, there is a frequency window that promotes hydrate formation. High-frequency fields disrupt the hydrogen bonds within the hydrate phase, accelerating decomposition. Fields with suitable frequency disrupt hydrogen bonds in the liquid, improving gas–liquid interaction and facilitating hydrate formation. By applying an intermittent electric field of 1 V/nm at 4 THz, high-speed, stable methane-hydrate growth was achieved, with a growth rate five times that of a control system without an electric field. These findings elucidate, at the molecular scale, the mechanism by which a cosine-oscillating electric field governs methane storage and release in the ZIF-8 adsorption-hydrate method and provide theoretical guidance for developing efficient methane storage and transport technologies.