Controlling and tuning CO2 hydrate nucleation and growth by metal-based ionic liquids

The complex kinetic process of CO 2 hydrate formation limits its applications of CO 2 capture and sequestration et al. In this work, the effects of metal-based ionic liquids with different cations and anions on CO 2 hydrate nucleation and growth was studied. The results showed that CO 2 hydrate nucleation was promoted by the anions of [NiCl 3 ] - , [MnCl 3 ] - , [FeCl 4 ] - , [C 8 MIM] + and [C 16 MIM] + ions due to the enhancement of local hydrogen-bonding network to construct crystal nuclei. The induction time of CO 2 hydrate nucleation was decreased by 75.0% in the [C 16 MIM]FeCl 4 aqueous solution. However, CO 2 hydrate nucleation was inhibited by [C 2 MIM] + and [ZnCl 3 ] - anion. The gas storage capacity of CO 2 hydrate was increased by mass transfer channels around the metal complex anions which could accelerate the diffusion rate of H 2 O and CO 2 molecules. The co-effect between [C 16 MIM] + cations and [FeCl 4 ] - anions on CO 2 hydrate growth was the strongest, which increased gas storage capacity by 16.1%. Hence, CO 2 hydrate formation can be controlled and tuned by changing cations and anions of metal-based ionic liquids.