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

Abstract Herein, we report the synthesis and enhanced Cu(II) ions sorption performance of SiO 2 @GO-NH 2 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 SiO 2 @GO-NH 2 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 SiO 2 @GO-NH 2 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 @GO-NH 2 . A series of experiments suggested that the Cu(II) ions are adsorbed on the SiO 2 @GO-NH 2 surface by forming covalent bonds with available functional groups (–NH 2 and –NH–). In other words, the adsorption process in SiO 2 @GO-NH 2 is a chemical sorption process. These findings indicate that SiO 2 @GO-NH 2 can be served as a promising sorbent for the efficient recovery and cost-effective elimination of Cu(II) ions from wastewater.