Assesment of phosphate functionalised silica gel (PFSG) for separation and recovery of uranium from simulated silicide fuel scraps dissolver solution (SSFSDS)

Phosphate Functionalized Silica Gel (PFSG) has been synthesized by reaction of DEHPA with modified silica gel. PFSG has been characterized by Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray Spectroscopy (EDS), Thermo-Gravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FT-IR) and X-Ray Photoelectron Spectroscopy (XPS) techniques. With PFSG the following studies for uranium sorption have been carried out: sorption kinetics, sorption isotherm, effect of feed acidity, effect of other metal ions on uranium sorption, desorption of uranium from loaded PFSG. Sorption kinetics is fast; equilibrium is achieved within five minutes with the sorbent dose of 5 gL(-1). Sorption kinetics follows the pseudo-second-order kinetic model. Sorption isotherm folllows Freundlich isotherm model, indicating that the process has belonged to chemical sorption. Quantum chemical calculations have been carried out to understand the binding of uranium with DEHPA functional groups present in PFSG. Computed geometry nicely correlate with the experimental FT-IR spectra with 1: 2 (UO22+: DEHPA) ratio. PFSG shows desirable selectivity for uranium over other competing metal ions. PFSG has been tested for the recovery of uranium from Simulated Silicide Fuel Scraps Dissolver Solution (SSFSDS). Studies show that>99% uranium can be recovered using PFSG from SSFSDS. Thus PFSG has a potential applicability.