Adsorption isotherms and kinetics study for U(VI) removal by excellent sorbent materials graphene oxide and functionalised graphene oxide

Abstract

In this paper, the graphene oxide (GO) and carboxylic functionalized graphene oxide (COOH-GO) were synthesized for the removal of U(VI) ion in samples of water. The structures of prepared GO and COOH-GO were confirmed by X-ray diffraction (XRD), Scanning electron microscope (SEM), Fourier transformed infrared (FTIR) spectroscopy, Raman spectra, and high-resolution transmission electron spectroscopy (HR-TEM). An adsorption study was carried out for these and it has been found that COOH-GO has more excellent adsorption property at 4.5 pH. The batch adsorption was studied successfully by the effect of initial uranium concentration, pH of the medium, sorbent dose, temperature, and contact time efficiency. The adsorption isotherms were studied successfully for Langmuir and Freundlich. The kinetics were studied successfully and fitted for the pseudo-first-order and pseudo-second-order model. The maximum adsorption capacities at pH 4.5 were calculated for COOH-GO, GO, and graphite. The thermodynamic studies revealed that adsorption is endothermic and spontaneous.