Impregnation of Polyethylenimine in Mesoporous Multilamellar Silica Vesicles for CO₂ Capture: A Kinetic Study

Amine-impregnated solid sorbents have been approved as one of the promising sorbents for CO₂ capture. However, the low adsorption rate seriously limits their real application. Herein, we synthesized the mesoporous multilamellar silica vesicle (MMSV) and used them as a novel support for the impregnation of polyethylenimine (PEI). The mesoporous multilamellar structure, as well as the presence of surfactant templates, significantly improved the dispersion of PEI in sorbents and hence improved both adsorption capacity and adsorption rate simultaneously. Among various MMSV-PEIs samples, MMSV­(a)-PEI-60% showed the best CO₂ adsorption capacity, up to 4.73 mmol/g in pure and dry CO₂ flow at 90 °C, and even exhibited a 22% enhancement in humid CO₂ flow at 75 °C. Moreover, it also presented good adsorption/desorption cyclic performance. The kinetic study showed that the second-order kinetic model fitted quite well for dynamic CO₂ adsorption, and the adsorption rate constants revealed its faster adsorption rate and higher amine efficiency compared with most reported amine-impregnated sorbents