Optimizing palm tree wood-derived activated carbon surface using RSM-CCD for continuous wastewater treatment and enhancing CO2 capture using sulfur modified-activation

Abstract

Developing highly efficient adsorbents is essential for overcoming diverse environmental and industrial challenges, especially in wastewater treatment and CO₂ capture. In this work, palm tree wood–derived activated carbon (AC) was optimized for these applications using Response Surface Methodology (RSM), examining how various synthesis conditions and activators influence performance. The synthesis parameters, including temperature, activation time, and activator concentration, were optimized to achieve high surface area and porosity, which are critical for efficient adsorption processes. Additionally, the impact of various activators, including potassium hydroxide (H₃PO₄) and potassium thiosulfate (K₂S₂O₃), was analyzed. The optimized AC was extruded for use in a continuous wastewater treatment system, effectively adsorbing cefixime (CFX), and was also utilized for CO₂ capture, demonstrating its multifunctional capabilities. Optimum breakthrough time for CFX adsorption and CO₂ adsorption capacity was found to be 90 min and 4.73 mmol.g⁻¹, respectively. The Thomas kinetic model provided an excellent fit to the obtained adsorption data. Optimum H₃PO₄-AC removed 96.33 % of CFX (30.68 % utilization of adsorption capacity), while K₂S₂O₃-AC achieved 79.33 % removal (25.27 % utilization of adsorption capacity). H₃PO₄ activation proved more favorable for CFX adsorption due to enhanced surface functionality, while K₂S₂O₃ activation significantly improved CO₂ capture by promoting stronger adsorption of CO₂ molecules.