Preparation of amidoxime-functionalized biopolymer/graphene oxide gels and their application in selective adsorption separation of U(VI) from aqueous solution

The amidoxime-functionalized biopolymer/graphene oxide gels were prepared and their performance in the application of the adsorption separation of uranium (VI) in aqueous solution has been studied. The prepared gels were characterized by using scanning electron microscopy, energy dispersive spectroscopy, Fourier transformed infrared spectra, and X-ray diffraction to determine the microscopic morphology, chemical composition and crystal structure. The adsorption performance of the gels including the effects of solution pH and contact time on the adsorption capacity has been evaluated by a batch adsorption technology. The adsorption isotherms and kinetics were measured, and the experimental data were analyzed and shown to be agreed with the Langmuir isotherm and the pseudo-second-order kinetic model. The results demonstrated that the adsorption process was the rate-limiting step in the separation process. (author)