Performance of metal-functionalized rice husk cellulose for CO2 sorption and CO2/N2 separation

Abstract

In this work, cellulose was extracted from rice husk. Fe3O4 and TiO2 particles were successfully bonded on the cellulose surface via hydroxyl group. The products were confirmed and characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). A pressure decay technique was carried out to evaluate CO2 sorption capacity and reusability. In addition, ab Initio calculations were performed. The experimental results show an increase in CO2 sorption ability upon cellulose modification with metal oxides. Titanium dioxide modified cellulose fibers (cellulose-TiO2, 184.1 mg/g at 30 bar and 298.15 K) and iron oxide modified cellulose fibers (cellulose-Fe3O4, 130.6 mg/g at 30 bar and 298.15 K) exhibited enhanced CO2 uptake than nonmodified cellulose (cellulose, 81.6 mg/g under the same conditions). The best CO2/N2 selectivity result was obtained for cellulose-TiO2 (3.56 ± 0.16). Selective capacity of cellulose-TiO2 for CO2/N2 was approximately 270% higher than raw cellulose fibers. CO2 sorption recycling experiments demonstrated high stability and reuse capacity in CO2 capture processes of Cellulose-TiO2.