Magnetic Modification of Tea Waste for Uranium Adsorption

Abstract

Tea waste (TW) was crushed into powder and mixed with graphene oxide (GO) in water, followed by adjusting the pH value of the resulting suspension with ammonia, adding FeCl2·4H2O under magnetic stirring, filtration and drying to prepare a rGO/Fe3O4/TW composite. The microstructure and crystal phase of the composite were characterized by FTIR and XRD. The effects of the pH value, adsorption time and initial uranium concentration on the uranium removal rate were investigated. Results indicate that rGO/Fe3O4/TW has excellent adsorption performance with an uranium removal rate up to nearly 100% in a short time at an initial uranium concentration of 10 mg. L-1. The maximum adsorption capacity of rGO/Fe3O4/TW is 103.84 mg. g-1 while that of TW is 97.70 mg. g-1. The rGO/Fe3O4/TW adsorbed with uranium is easily separated from the solution by appying magnetic field. The isotherm and kinetics of uranium adsorption on rGO/Fe3O4/TW are best fitted by the Langmuir isotherm model and the pseudo-second-order model. The rGO/Fe3O4/TW and TW have a good reusability with an uranium removal rate of about 85% after five cycles.