Francis Ngoye^{1, 2,}, Ornellia Nargess Ozenga¹, Pradel Tonda-Mikiela¹, Rodrigue Safou Tchiama², Charly Mve Mfoumou¹

Co-carbonizing agricultural residues represents an efficient strategy to tailor activated carbon properties while reducing chemical activating agents. In this work, activated carbons (ACs) were prepared by blending sugarcane bagasse and coconut shell at different mass ratios, followed by pre-carbonization at 350 °C, KOH impregnation at a low mass ratio of 0.1:1 (w/w), and activation at 600°C. Characterization via Boehm titration, pH_pzc, iodine number, and methylene blue number revealed that the precursor ratio influences both structural and chemical properties. Specifically, the bagasse-rich blend (CA-B80) showed the highest estimated specific surface area (576 m².g^-1) and micropore volume (0.382 cm³.g^-1) among the samples, pointing to a positive textural effect during co-carbonization. Conversely, the coconut-rich blend (CA-B20) presented the highest concentration of carboxylic groups (1.31 mmol.g^-1), suggesting a distinct trend in surface chemistry enhancement. In batch adsorption tests, CA-B50 and CA-B20 achieved methylene blue uptake capacities of 492 and 477 mg.g^-1, respectively, outperforming single-precursor analogues. These findings demonstrate that co-carbonization provides a sustainable and cost-effective route to valorize tropical biomass wastes with minimal chemical demand.

Activated carbons, Sugarcane bagasse, Coconut Shell, Co-Carbonization, Low KOH Activation, Methylene blue adsorption