Developing slurry based on immobilized and aqueous [MEACl][EDA] for CO2 capture

Abstract

The urgent need to mitigate climate change and reduce greenhouse gas emissions has underscored the importance of developing effective CO2 capture technologies. In this study, a novel strategy was proposed and developed, where adding cosolvent and immobilizing deep eutectic solvent (DES) were combined to enhance the performance from capacity to rate. To this end, [MEACl][EDA] (1:5) was chosen as the DES, H2O was used as the cosolvent, and silica was selected as the substrate to immobilize the DES; the effects of the DES immobilization amount and the concentration of the immobilized DES particles in the aqueous system as well as temperature on the viscosity and CO2 capture performance were investigated systematically. Compared to the aqueous DES, the slurry exhibited higher CO2 uptake and improved kinetics, comparable viscosity before CO2 capture, and slightly high viscosity after CO2 capture, where the best sample (3 wt% of (5 wt% DES@silica) in 40 wt% aqueous DES) showed a capacity of 24.93 wt% at the room temperature (22 ℃) and viscosities of 7.32 and 21.82 mPa·s before and after CO2 capture. Also, the CO2 capture rate of the slurry reached 1.4 mol CO2/(kg sorbent·min) after 2 min at 22 ℃, which was higher than the aqueous DES without immobilized DES (1.24 mol CO2/(kg sorbent·min) under the same condition). The prepared slurries showed high stability (over one month) and high regeneration (∼91 % CO2 capture recovery after 5 cycles).