Sustainable activated carbon production from sunflower seeds via chemical activation

Abstract

The increasing demand for high-performance activated carbon necessitates applying sustainable and cost-effective production methods. This study explores the use of biochar derived from renewable biomass. The primary feedstock for biochar consisted of woody residues from composting, along with pre-dried sunflower seed shells that had a moisture content of around 10% as a precursor for the production of activated carbon. The process started with carbonization followed by potassium hydroxide (KOH) activation. Key parameters such as the impregnation ratio, temperature, and activation time were optimized to enhance the physicochemical properties of the activated carbon. Under optimized conditions, namely a KOH-to-biochar impregnation ratio of 3:1, an activation temperature of 800 °C, and an activation duration of 5 h, the yield of activated carbon was 58% and the specific surface area was 498 m²/g. A significant enhancement in surface area, with a maximum value of 709 m²/g, was achieved after increasing the time to 24 h of activation. Differential Scanning Calorimetry (DSC) analysis was applied to evaluate the CO₂ adsorption performance of both biochar and activated biochar at 30 °C, demonstrating a 30% improvement in adsorption efficiency following activation. This study underscores the potential of biochar as a renewable and sustainable precursor for the production of high-performance activated carbon. This study underscores the potential of biochar derived from agro residue as a source for the production of high-performance activated carbon. The findings contribute to the advancement of environmentally friendly production technologies and highlight the potential applicability of biochar-derived activated carbon in gas adsorption and environmental remediation.