Synergistic Effect of Boric Acid and Sodium Dodecyl Sulfate in Promoting CO2 Hydrate Formation under Static Conditions

Abstract

Hydrate-based CO₂ capture and storage (HCCS) is a promising approach to mitigate the greenhouse effect. However, the formation rate of the CO₂ hydrate is extremely slow, making it difficult to industrialize the HCCS technology. Here, we first report that the synergistic combination of boric acid (BA) and sodium dodecyl sulfate (SDS) significantly promotes CO₂ hydrate formation under static conditions. At the optimum concentration ratio (0.3 wt % BA + 0.2 wt % SDS), the capacity of the composite system reached 323.5 mg g^–1, which is much higher than that of 0.5 wt % BA (47.7 mg g^–1) or 0.5 wt % SDS (49.9 mg g^–1). In addition, visual observations of the morphologies of the produced CO₂ hydrates indicated that the promotion mechanism was based on the capillary-driven theory. This work may open the door to the design of highly effective CO₂ hydrate promoters for HCCS technology.