Functionalization of graphene oxide sheets with magnetite nanoparticles for the adsorption of copper ions and investigation of its potential catalytic activity toward the homocoupling of alkynes under green conditions

This paper deals with the preparation of graphene oxide sheets (GO) modified with magnetite nanoparticles (Fe3O4NPs) for removing Cu(II) ions from aqueous solutions. Moreover, the recovered Cu(II)-based material was recycled as a catalyst for the homocoupling of a series of alkynes. The adsorption behavior of magnetic GO-based materials towards Cu(II) ions from aqueous solutions was studied as a function of the pH value and the contact time and it was observed that the magnetic GO-based absorbent can be separated quickly from its aqueous solution by using an external magnetic field. Its equilibrium adsorption capacity value for Cu(II) ions was as high as 3.808 ± 0.125 mmol.g−1 under neutral conditions. In addition, the catalytic activity of the resulting [GO-EDA-CAC@Fe3O4NPs]-BPED-Cu(II) material toward the homocoupling of phenylacetylene into 1,4-diphenylbuta-1,3-diyne was demonstrated with a yield up to 99%. Importantly, the [GO-EDA-CAC@Fe3O4NPs]-BPED-Cu(II) supported catalyst was consecutively reused for fifteen runs without a significant loss of its activity.