Preparation of phosphate-functionalized biopolymer/graphene oxide gels for enhanced selective adsorption of U(VI) from aqueous solution

The adsorption properties of phosphate-functionalized biopolymer/graphene oxide gels on U(VI) in aqueous solution were studied. The characterization of prepared gels were measured by scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), Fourier transformed infrared spectra (FT–IR), and X-ray diffraction (XRD). The adsorption of U(VI) was evaluated as a function of the pH of solution, initial uranium concentration and the contact time, and the optimum conditions for U(VI) adsorption was obtained. The Langmuir isotherm model fits the experimental data very well, and the maximum uptake of U(VI) were 568.18 mg/g for P-TA-GO and 546.45 mg/g for P-AL-GO, respectively. The experimental data for the kinetics of adsorption correlated well with the second-order Langergren rate equation, and Langergren rate constants have been determined. Compared to other coexisting ions present in real-world uranium-containing wastewater, the phosphate-functionalized biopolymer/graphene oxide gels have demonstrated remarkably better selective adsorption to U(VI).