U(VI) sorption during ferrihydrite formation: Underpinning radioactive effluent treatment.

摘要: Abstract Iron (oxyhydr)oxide nanoparticles are known to sorb metals, including radionuclides, from solution in various environmental and industrial systems. Effluent treatment processes the Enhanced Actinide Removal Plant (EARP) (Sellafield, UK) use a neutralisation process induce precipitation of iron (oxyhydr)oxides remove radionuclides solution. There is paucity information on mechanism(s) U(VI) removal under conditions relevant such processes. Here, we investigated simulated effluents containing 7.16 mM Fe(III) with 4.2 × 10−4–1.05 mM U(VI), during base induced hydrolysis Fe(III). The solid product was ferrihydrite all conditions. Acid dissolutions, Fourier Transform infrared spectroscopy thermodynamic modelling indicated that removed by adsorption ferrihydrite. sorption mechanism supported X-ray Absorption Spectroscopy which showed adsorbed via bidentate edge-sharing inner-sphere species carbonate forming ternary surface complex. At concentrations ≤0.42 mM entirely adsorption, however at 1.05 mM there also evidence for discrete phase. Overall these results confirm sequestered over concentration range 4.2 × 10−4–0.42 mM confirming remarkably consistent this industrially system.