Synthesis of activated carbon fibers from cotton by microwave induced H₃PO₄ activation

The preparation of activated carbon fiber (ACF) with cotton as raw precursor via microwave assisted H₃PO₄ activation was explored in the present study. The influence of microwave power, activation time and acid concentration on the properties of activated carbon fiber was investigated. The ACF with maximum surface area and total pore volume of 1370 m²/g and 0.98 cm³ was prepared at microwave input power of 640 W, activation time of 10 min and H₃PO₄ concentration of 50% (Wt.). The ACF was tested with methylene blue (MB) dye adsorption and the equilibrium adsorption capacity was 476 mg/g, with the adsorption isotherm following the Langmuir isotherm model. The adsorption kinetic followed the pseudo-second-order kinetic model, while the adsorption mechanism was well described by the film diffusion model. The experimental results indicated the potential of cotton as good precursor for the preparation of ACF with promising adsorption capacity by microwave heating.