Sustainable and novel biomass‐derived adsorbents for post‐combustion carbon capture: Preparation, characterization, and adsorption performance studies

Abstract This study investigates the development of low‐cost biomass‐derived activated carbons from walnut shell (WS), rice straw (RS), and sugarcane bagasse (SB) for post‐combustion CO 2 capture via physical adsorption. A one‐step simultaneous carbonization and chemical activation approach is employed to synthesize the adsorbents. The prepared adsorbents are characterized using proximate and ultimate analyses, Brunauer–Emmett–Teller (BET)‐surface area analysis, Barrett–Joyner–Halenda (BJH)‐pore size distribution analysis, Scanning Electron Microscopy (SEM)‐surface morphology analysis, Fourier Transform Infrared Radiation Spectrometer (FTIR)‐surface functional group analysis, and Thermogravimetric Analysis (TGA)‐thermal stability techniques to evaluate their physicochemical and surface textural properties. The SBA adsorbent exhibited the highest BET surface area of 2489 m 2 g −1 and pore volume of 1.75 cm 3 g −1 , followed by WSA (1876 m 2 g −1 , 0.96 cm 3 g −1 ) and RSA (1584 m 2 g −1 , 0.78 cm 3 g −1 ). CO 2 adsorption experiments are conducted at temperatures ranging from 0 to 30°C and pressures up to 1 bar. Among the adsorbents, SBA achieved the highest CO 2 uptake capacity of 6.69 mmol g −1 at 0°C and 1 bar, while WSA and RSA achieved 6.16 mmol g −1 and 5.58 mmol g −1 , respectively. The superior adsorption performance of SBA is attributed to its enhanced porosity, larger surface area, and abundant active adsorption sites. Dynamic breakthrough studies further confirmed the higher adsorption capability of SBA with a breakthrough uptake of 0.89 mmol g −1 . The isosteric heat of adsorption values below 40 kJ mol −1 confirmed that the adsorption process predominantly followed physisorption behavior. The findings demonstrate that biomass‐derived activated carbons produced from agricultural residues possess excellent potential as sustainable and efficient adsorbents for post‐combustion carbon capture applications.