Removal of uranium(VI) from aqueous solution using graphene oxide functionalized with diethylenetriaminepentaacetic phenylenediamine

A novel chelator diethylenetriaminepentaacetic phenylenediamine (DTPAA) was successfully synthesized using p-phenylenediamine and diethylenetriaminepentaacetic acid. The as-synthesized DTPAA was covalently bonded to a supporting matrix of graphene oxide (GO), and a composite material (GO-DTPAA) was obtained. The structure of GO-DTPAA was characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The morphology was observed using scanning electron microscope (SEM) and Raman spectroscopy. The adsorption of uranium(VI) from aqueous solution was investigated using GO-DTPAA via batch experiments. Results indicated that GO-DTPAA was a highly efficient absorbent for the removal of uranium (VI) from aqueous solution at pH 6.5. Kinetics and adsorption isotherm investigations revealed that the adsorption process was well-fitted by pseudo-second-order kinetics and by the Langmuir isotherm. The adsorption capacity of GO-DTPAA was as high as 485.0 mg·g^?1 at 298.15 K, which was far greater than that of pristine GO (97.3 mg·g^?1) at the same temperature.