Adsorption of xanthate from aqueous solution by multilayer graphene oxide: an experimental and molecular dynamics simulation study

Xanthate has become the main organic pollutant in mine wastewater because of its widespread use as a flotation collector. Multilayer graphene oxide (MGO) exhibits excellent adsorption performance in removing organic contaminants from aqueous solutions that is attributed to its rich oxygen-containing functional groups and large specific surface area. MGO was prepared using the modified Hummers method. Moreover, MGO was characterised by Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). The adsorption of xanthate by MGO follows the Langmuir model, and thermodynamic studies have shown that the adsorption process can be completed spontaneously. The results of XPS analysis indicated that the oxygen content on the MGO surface decreased after the adsorption of xanthate, and the proportion of oxygen-containing functional groups was also significantly lower than that before adsorption. Molecular dynamics studies revealed that the head group of xanthates was closer to the surface of the MGO than the tail group. This research indicates that MGO can be successfully used to adsorb xanthate. In addition, the dispersion force between the head group of xanthates and the oxygen-containing functional group on the MGO surface was the dominant factor affecting the adsorption process. Multilayer graphene oxide can be used to remove xanthate in aqueous solutions, and the oxygen-containing groups on multilayer graphene oxide can provide adsorption sites for xanthate.