Polyethyleneimine (PEI) loaded MgO-SiO2 nanofibers from sepiolite minerals for reusable CO2 capture/release applications

CO 2 capture and storage (CCS) by advanced materials and technologies will play a significant role in reducing industrial or human caused CO 2 emissions. In this article, a clay mineral based CO 2 absorbent was prepared by impregnating polyethyleneimine (PEI) onto acid modified fibrous sepiolite . X-ray diffraction (XRD), Fourier transform microscopy (FTIR), thermogravimetric analysis (TGA), and N 2 adsorption - desorption isotherms accompanied BET (Brunauer-Emmett-Teller) analysis were used to characterize the raw mineral and the prepared absorbents as well as their CO 2 adsorption performances. After the acid treatment, the raw sepiolite changed into amorphous silica (SiO 2 ) containing a small amount of MgO , but maintained their nanowire morphology, the S BET value of acid treated Sep was 4 times larger and pore volume was about 2 times higher than the raw mineral. The MgO-SiO 2 nanowires and polyethyleneimine (PEI) successfully formed an organic-inorganic hybrid composite. A maximized adsorption capacity of 2.48   mmol/g at 75   °C was reached in CO 2 adsorption/desorption measurement when the composite contained 50   wt% PEI. The product also showed an excellent adsorption repeatability, above 98% of the optimized CO 2 adsorption capacity could be maintained after 10 circles tests, which confirmed that the fibrous MgO-SiO 2 assembly optimal amount of PEI is a promising solid absorbent in CO 2 gases controlling fields.