Adsorption behavior of copper ions from aqueous solution onto graphene oxide-CdS composite

Graphene oxide (GO)-CdS composite (GO/CdS(en)) is prepared by liquid insertion method with addition of ethylenediamine (en) in synthesis process. The properties of the composite are characterized by FT-IR, XRD, TEM, Raman spectroscopy and N-2 physical adsorption, respectively. The adsorption capacity of the composite was evaluated by the removal of copper ions from aqueous solution. Effect of several factors including the initial pH, absorbent dose and contact time on removal efficiency of copper ions was investigated by batch experiment. The results show that the GO/CdS(en) composite exhibits excellent adsorption capacity for Cu(II) ions and has good chemical stability. Under the optimum experimental conditions, the removal rate of copper ions can reach ca. 90%. Also, the adsorption isotherm was investigated by both Langmuir and Freundlich models. The adsorption process was found to be well-described by Langmuir model. Thermodynamics parameters suggest that Cu(II) ions adsorption on the GO/CdS(en) was an endothermic and spontaneous process. (C) 2014 Elsevier B.V. All rights reserved.