Transforming palm waste into poly(acrylamide–acrylic acid) modified green carbon fibers: A sustainable high-performance adsorbent for CO₂ capture

The excessive emission of carbon dioxide (CO₂) from anthropogenic activities poses a critical challenge to global climate stability, necessitating efficient and sustainable capture technologies. In response, this study introduces a novel adsorbent material, poly (acrylamide/acrylic acid) modified green carbon fiber (PAAGCF), that synthesized from waste palm leaves to tackle CO₂ capture efficiently. The base green carbon fibers (GCF) were prepared through carbonization and nitric acid activation, and then functionalized via in situ polymerization of acrylamide and acrylic acid. The resulting PAAGCF exhibited substantial improvements in porosity and surface chemistry, as confirmed by XRD, FTIR, TGA, SEM, and BET analysis. Polymer grafting introduced abundant amide and carboxylic groups, which enhanced CO₂ affinity, while increasing BET surface area to 358.14 m²/g and total pore volume to 3.072 cm³/g. The material demonstrated high CO₂ uptake capacities of 29.81 mmol g⁻¹ at 0 °C and 18.77 mmol g⁻¹ at 25 °C with CO₂/N₂ selectivity values around 38–40. Thermodynamic and modeling studies confirmed exothermic physisorption (−28.34 kJ/mol), surface heterogeneity (Freundlich model, R² = 0.989), and chemisorption-driven kinetics (PSO model, R² = 0.903). These results underscore the novelty and effectiveness of PAAGCF as a renewable, cost-effective, and high-performance material for scalable CO₂ capturing and environmental remediation.