Performance of a Functionalised Polymer-Coated Silica at Treating Uranium Contaminated Groundwater from a Hungarian Mine Site

Abstract

The performance of an active material for treating uranium contaminated groundwater within a permeable reactive barrier (PRB) is reported. This material, called PANSIL, has a tailored ligand system that selectively removes the uranyl (UO 2 2+) cation from solution. The active uranyl ligand in PANSIL is a polyacryloamidoxime resin derived from polyacrylonitrile, which is deposited from solution onto the surface of quartz sand to form a thin film coating.PANSIL is effective at sequestering cationic and neutral uranyl species when the solution pH is above 4, due to the stability of the polyacryloamidoxime-uranyl complex formed. However the rate of sequestration decreases rapidly when the pH exceeds about 8 where neutral uranyl species are present only at very low concentrations. It can preferentially sequester UO 2 2+ in the presence of typical divalent groundwater cations. In mildly alkaline conditions the sequestration performance in groundwater is sensitive to the concentration of uranyl complexing ligands, such as bicarbonate. Such behaviour has important consequences for PRB design as it will determine the barrier thickness required to treat a particular groundwater flow rate.1

Unsafe drinking water quality in remote Western Australian Aboriginal communities

“…Consequently, ferric iron can convert insoluble uranium dioxide, UO 2 (U 4+ ) to soluble UO 2 +2 ions (U 6+ ) thus mobilising the uranium (Scharer & Ibbotson, ). Evidently, the groundwater biogeochemistry of uranium is quite complex, making the treatment of contaminated groundwater difficult (Stewart et al ., ).…”