Activated carbon fibers of high surface area from corn husk: Mono and multicomponent adsorption studies of Pb2+ and Cu2+ ions from aqueous solution

Abstract

The present work reports the preparation of activated carbon fibers (ACF) from corn husk through the slow pyrolysis process in the presence of H3PO4. The ACF were properly characterized, exhibiting morphological characteristics of microfibers, high surface area (SBET = 1824 m2/g), and acidic surface properties (pHpcz = 3.85). Adsorption studies for mono and multicomponent systems of Pb2+ and Cu2+ ions in aqueous solution were carried out and kinetic models of pseudo-first-order, pseudo-second-order, and Elovich, and equilibrium models of Langmuir, Freundlich, and Dubinin-Radushkevich, as well as, multicomponent adsorption models of modified Langmuir, extended Freundlich, and Sheindorf-Rebuhn-Sheintuch were fitted to the experimental data. The results showed the ACF exhibited high adsorption capacity in the monocomponent system (Pb2+= 210.6 mg g−1, Cu2+= 212.9 mg g−1), which decreased for the multicomponent system (Pb2+ = 101.6 mg g−1; Cu2+ = 56.1 mg g−1). Furthermore, the adsorption process involved both physisorption and chemisorption reactions and it was considered spontaneous and endothermic.