CO2 capture through the hydrophilic functionalized CNTs in boosting the separation efficiency from flue gas based on the hydrate method

CO 2 capture is one of the most straightforward ways for solving the greenhouse gas effects. Hydrate-based CO 2 capture from flue gas has been considered as an emerging green technology owing to its low energy consumption, cost-effectiveness, and environmental benefits. In this study, the hydrophilic functionalized multi-walled carbon nanotubes (FMWCNTs) were modified and applied for CO 2 capture from flue gas by combining the dynamic experiments towards CO 2 hydrate formation and theoretical simulations. Firstly, the selective adsorption towards CO 2 in the simulated flue gas was greatly improved by regulating the hydrophilic functional groups, especially for COOH groups on the surface. Particularly, FMWCNTs induced a rapid accumulation of CO 2 , which largely shortened the hydrate nucleation time to 13 min, reducing by 59.4 % compared to the pristine THF system. This further promoted the formation of CO 2 hydrate crystals and enhanced the hydration rate and gas consumption. As a result, the CO 2 storage capacity achieved 6.48 mmol/(mol·H 2 O), with the highest separation efficiency of 76.3 %, which increased by 23.6 % and 22.7 % than that of SDS-based traditional accelerators. Particularly, the low concentration of 0.01 wt% FMWCNTs still achieved a high separation efficiency of 73.4 %, showing a great potential as kinetic accelerators with low dosage. The present study could provide novel insights into the development of modified carbon nanotubes as the kinetic accelerators for CO 2 capture.