Mechanism of the Adsorption Process: Cu²⁺ Adsorpted by Ramie Stalk

Abstract

Agriculture wastes, ramie stalk, was used to adsorb Cu 2+ ion from the aqueous solutions. Adsorption behaviors and mechanism involved in were systematically explored and discussed. A better fitting result of adsorption isotherms of Cu 2+ to ramie stalk was obtained from the Langmuir model. This suggested the surface of ramie stalk is rather homogeneous, which is supported by a better fitting result of the adsorption kinetic by using a pseudo-first-order kinetic model. Following surface complexation modeling suggested Cu 2+ uptake is driven by water-associated adsorption along with the precipitated CuO species. This is attributed to the low dissociation constant of ramie stalk and thus there was only around one quarter of surface adsorption sites participating Cu 2+ uptake at acidic environment.