Synthesis, characterization of carbon adsorbents derived from waste biomass and its application to CO2 capture

Waste Entada Rheedii shell (ERS) was used for the preparation of biochar-based adsorbents for CO2 capture at ambient conditions. Three types of adsorbents were prepared by treating ERS with acid, base and neutral condition. The physico-chemical properties of synthesized carbons were derived by X-ray diffraction, N-2 adsorption, Fourier-transform infrared spectroscopy, C-13-Nuclear magnetic resonance spectroscopy, Laser Raman, Field emission scanning electron microscopy (FESEM), CHNS elemental and thermo gravimetric analysis. Characterization results indicated that the surface area and presence of basic sites in the carbon depended on the nature of pre-treatment of shell. The CO2 adsorption ability of the ERS derived carbons was tested at ambient temperatures. Carbon prepared after acid treatment showed superior CO2 adsorption capacity. The reasons for high CO2 adsorption behavior of the carbons were explained by its characteristics. The adsorption capacity in presence of moisture was also estimated. These carbon adsorbents also exhibited recyclability without any change in its adsorption capacity.