Abstract:

A series of fumed silica materials with different polyethyleneimine（PEI） loadings as CO₂ adsorbents were prepared by using the equal-volume impregnation method.The composition，structure，actual loading amount of PEI，and thermal stability of the adsorbents were characterized by X-ray diffraction（XRD），scanning electron microscopy（SEM），thermogravimetric analysis（TGA），Fourier-transform infrared spectroscopy（FT-IR），and nitrogen physical adsorption measurements.The effects of PEI relative molecular weight，loading amount，and environmental temperature on the CO₂ adsorption performance of the adsorbents were investigated.It was found that the 50%-PEI（600）-SiO₂ adsorbent exhibited the best CO₂ adsorption performance at 100 ℃，with a maximum adsorption capacity of 130.6 mg/g when the relative molecular weight of PEI was 600 and the loading amount was 50%（mass fraction）.Furthermore，the adsorbent showed excellent cyclic performance，with only 4.8% performance loss after 5 cycles.The adsorbent was cost-effective and held great potential for application in CO₂ capture from thermal runaway flue gases of lithium-ion batteries.

Key words: amine-functionalized material, silica material, solid adsorbent, CO₂ adsorption