Synthesis of composite hydrogel of glutamic acid, gum tragacanth, and anionic polyacrylamide by electron beam irradiation for uranium (VI) removal from aqueous samples: Equilibrium, kinetics, and thermodynamic studies

A bio-compatible hydrogel sorbent was prepared through chemical conjugation of glutamic acid (GA) with gum tragacanth (GT) followed by mixing with anionic polyacrylamide (PAAm) and irradiating by the electron beam. The prepared composite of the hydrogel of GA-GT/PAAm was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, point zero charge (PZC) analysis, thermogravimetric analysis (TGA), and X-ray diffraction-(XRD). The sorption capability of the hydrogel was investigated for the removal of U(VI) from aqueous samples. The sorption data were analyzed by Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models and the experimental results were in agreement with Langmuir isotherm. The sorption process was found to be endothermic and spontaneous. The maximum sorption capacity of the composite of GA-GT/PAAm hydrogel for U(VI) determined from Langmuir isotherm was 384.6 mg g(-1). The experimental data were also analyzed by four different kinetic equations, and the results were fitted well with the pseudo-second-order model.