Fast removal of samarium ions in water on highly efficient nanocomposite based graphene oxidemodified with polyhydroquinone: Isotherms, kinetics, thermodynamics and desorption

Nowadays, the removal of the rare-earth elements in water and hydrogeosystems is an urgent issue. Therefore, graphene oxide / polyhydroquinone nanocomposite was used to remove samarium ions (Sm3+) in aqueous solutions. The sorption and desorption of Sm3+ ions on the graphene oxide / polyhydroquinone nanocomposite from aqueous solutions are studied with contact time (15.0 min.), initial concentration (100.0 mg/L), the weight of sorbent (0.3 g/L), pH of a solution (6.0) and temp. (25C degrees). The rate constants of sorption, equilibrium sorption capacity, percentage sorption and desorption, entropy and enthalpy of Sm3+ extraction process are discussed. The analysis of the proceed mechanisms is conducted with the kinetic dependences and sorption isotherms, for which reason the empirical equations of pseudo-first and pseudo-second-order, Elovich and intraparticle diffusion, as well as the equations of Langmuir, Freundlich, Temkin, Dubinin-Radushkevich were used. It should be noted that the absorption of Sm3+ proceeded according to the mixed diffusion mechanism and is controlled by the interactions among the sorbent and the functional groups of the sorbent. According to Langmuir's model, the maximumsorption capacity of the developed sorbent was 357.14mg g(-1). Thus, the high efficiency of the developed sorbent for the purification and remediation of hydrogeosystems for samarium ions is useful. The reported method may be used for the removal of 360 million tons of wastewater with rare earth elements including samarium ions. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the use of graphene oxide/polyhydroquinone nanocomposite for the removal of samarium ions in aqueous solutions. Various parameters such as sorption and desorption were analyzed, and the maximum sorption capacity was determined using Langmuir model. The method shows potential for efficient purification and remediation of hydrogeosystems containing rare earth elements, including samarium ions.