Influence of preparation method on oxidation degree of graphene oxide and adsorption for Th (IV) and U(VI)

Abstract

Graphene oxide (GO) was prepared from graphite using Hummers' method, improved Hummers' method and modified Hummers' method. The samples were characterized by FT-IR spectroscope, TGA, XRD, XPS,SEM and element analysis. The results showed that graphene oxide was more oxidized prepared by the improved Hummers' method(IGO). The isothermal adsorption experiments of Th(IV) and U(VI) on graphene oxide showed that the maximum adsorption capacity of Th(IV) on IGO was 192.3 mg/g, increased by 38.5% as compared with that of GO prepared by Hummers' method. The maximum adsorption capacity of U(VI) was 156.2 mg/g, increased by 28.1%. Both of above values are in accord with Langmuir isotherm model. Furthermore, kinetic and thermodynamic parameters of Th (IV) and U(VI) adsorption on IGO were investigated by using batch experiments, confirming that adsorption fits pseudo-second kinetic equations, which are spontaneous and endothermic.