Post-combustion carbon dioxide adsorption of concurrent activated and surface modified palm kernel shell-derived activated carbon

Abstract

This research applied a concurrent activation and surface modification (CAM) process to synthesize palm kernel shell-derived activated carbon (PKSdAC) to obtain CO₂ affinity surface functionalization. The CAM process is a simplified activated carbon activation process that is cost-effective. The CAM process used in this study integrates sulphuric acid activation and barium chloride functionalization. The formation of barium sulphate is targeted to incorporate barium through a reduction process with carbon-containing material at elevated temperatures into PKSdAC to obtain basic metal surfaces functional group for chemical adsorption. The optimal temperature for CAM-PKSdAC CO₂ adsorption performance was at 40–60 °C, established through temperature-programmed desorption of CO₂ (TPD-CO₂) analysis. The CAM-PKSdAC adsorption performance was tested using a lab-scale adsorption system. The bed CO₂ content was determined using gas chromatography coupled with a thermal conductivity detector (GC-TCD) by manual syringe injection. CAM-PKSdAC exhibited a high CO₂ adsorption capacity of 0.89 mmol g⁻¹ from TPD-CO₂, and 1.91 mmol g⁻¹ from GC-TCD at 40 °C and 1 bar. It showed comparable CO₂ adsorption capacity to conventional surface modified-activated PKSdAC (1.96 mmol g⁻¹) while higher than commercial and modified ACs (1.14–1.60 mmol g⁻¹), but lower than potassium hydroxide modified ACs (1.81–2.10 mmol g⁻¹) at 40 °C and 1 bar. Barium promoted chemisorption of CO₂ as supplementary reaction, which increases adsorption capacity. The non-linear Dubinin Radushkevich model strongly correlates with the experimental adsorption data for CAM-PKSdAC adsorption, indicating the physisorption process via micropore filling on CAM-PKSdAC. CAM-PKSdAC showed moderate reusability with negligible variation in adsorption capacity after 10 adsorption–desorption cycles. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.