Study of CO-hydrate formation in contact with bulk nanobubbles: An investigation from experiment and molecular-dynamics simulations.

Hypothesis: Nanobubbles (NBs) have been extensively investigated as a sustainable promoter for gas hydrate nucleation, which also contribute to the hydrate memory effect. However, less attention afforded to their effects on the hydrate-growth process, thus lacking a complete perspective of the overall effects from NBs on hydrate formation. We hypothesize that their effect on CO hydrate growth may vary depending on the properties of NBs.

Experiments And Simulations: This study investigates CO-hydrate nucleation and growth with a dual methodology. Laboratory experiments were conducted using bulk NBs generated either from CO hydrate dissociation or electric-field-based electrostriction in virgin water. Simultaneously, molecular dynamics simulations examined hydrate growth in contact with a single NB containing CO molecules.

Findings: Experimental results indicate that NBs promote hydrate nucleation, with finer ones from electric fields leading to a slight promotion at the onset of hydrate growth, followed by inhibition. MD simulations reveal that while NBs can serve as a gas source for growth, denser NBs hinder the process due to stronger gas-water interactions and CO clustering. These results suggest that optimizing NB size and concentration is critical for maximizing gas-hydrate formation efficiency in industrial applications such as gas storage and carbon capture.