Investigation of the formation processes of CO2 hydrate films on the interface of liquid carbon dioxide with humic acids solutions

Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work. It was found that after the growth of the hydrate film at the interface, further growth of hydrate due to the suction of water in the capillary system formed between the wall of the cuvette and the end boundary of the hydrate layer occurs. Most probably, substantial effects on the formation of this capillary system may be caused by variations in reactor wall properties, for example, hydrophobic-hydrophilic balance, roughness, etc. We found, that the rate of CO₂ hydrate film growth on the surface of the humic acid aqueous solution is 4-fold to lower in comparison with the growth rate on the surface of pure water. We suppose that this is caused by the adsorption of humic acid associates on the surface of hydrate particles and, as a consequence, by the deceleration of the diffusion of dissolved carbon dioxide to the growing hydrate particle.