Biobased chitosan hybrid aerogels with superior adsorption: Role of graphene oxide in CO2 capture

Abstract

Currently extensive research is focused on developing and designing novel porous materials for clean energy and environmental applications such as reducing the emission of carbon dioxide (CO₂). In this work, hybrid monolith aerogels of chitosan (CTS), an environmentally-benign biopolymer, with different amounts of graphene oxide (GO) are prepared using freeze-drying. The sorption performance of the developed aerogels for CO₂ capture is studied. The aerogels are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and nitrogen adsorption–desorption measurements. Homogeneous dispersion of GO in CTS is studied beyond the particle concentration where agglomeration takes place. The effects of GO on the specific surface area of the aerogels and CO₂ capture are investigated and shown to increase with GO content. The BET surface area is dramatically increased from 153 to 415 m² g⁻¹ by loading 20 wt% GO into the CTS adsorbent. The amount of CO₂ adsorbed at 25 °C increases from 1.92 to 4.15 mol kg⁻¹ with the addition of 20 wt% GO. Adsorption–desorption cycles exhibit the stability of the hybrid aerogels during prolonged cyclic operations, suggesting excellent potential for CO₂ capture technology.