Amino group functionalized SiO2@graphene oxide for efficient removal of Cu(II) from aqueous solutions

Herein, we report the synthesis and enhanced Cu(II) ions sorption performance of SiO2@GO-NH2 by an easy, cost-effective and efficient synthesis protocol. Various characterization techniques are employed to study the structure, morphology, chemical composition and porous nature of as-synthesis SiO2@GO-NH2 nanocomposite. Mechanistic insight into the adsorption process has been provided by using pseudo-second-order and Langmuir model. The maximum adsorption capacity of 105.4 mg g(-1) has been attained at 308 K according to Langmuir model and the adsorption equilibrium has been attained within 35 min. The results reveal that as-synthesized SiO2@GO-NH2 possesses fast adsorption kinetics. For the first time, the adsorption mechanism of Cu(II) ions has been explained by using ex-situ post sorption characterization of Cu(II)-loaded SiO(2)OGO-NH2. A series of experiments suggested that the Cu(II) ions are adsorbed on the SiO2@GO-NH2 surface by forming covalent bonds with available functional groups (-NH2 and-NH-). In other words, the adsorption process in SiO2@GO-NH2 is a chemical sorption process. These findings indicate that SiO2@GO-NH2 can be served as a promising sorbent for the efficient recovery and cost-effective elimination of Cu(II) ions from wastewater. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.