Uranium removal from contaminated groundwater by synthetic resins.
Synthetic resins are shown to be effective in removing uranium from contaminated groundwater. Batch and field column tests showed that strong-base anion-exchange resins were more effective in removing uranium from both near-neutral-pH (6.5)- and high-pH (8)-low-nitrate-containing groundwaters, than metal-chelating resins, which removed more uranium from acidic-pH (5)-high-nitrate-containing groundwater from the Oak Ridge Reservation (ORR) Y-12 S-3 Ponds area in Tennessee, USA. Dowex 1-X8 and Purolite A-520E anion-exchange resins removed more uranium from high-pH (8)-low-nitrate-containing synthetic groundwater in batch tests than metal-chelating resins. The Dowex 21K anion-exchange resin achieved a cumulative loading capacity of 49.8 mg g(-1) before breakthrough in a field column test using near-neutral-pH (6.5)-low-nitrate-containing groundwater. However, in an acidic-pH (5)-high-nitrate-containing groundwater, metal-chelating resins Diphonix and Chelex-100 removed more uranium than anion-exchange resins. In 15 m L of acidic-pH (5)-high-nitrate-containing groundwater spiked with 20 mg L(-1) uranium, the uranium concentrations ranged from 0.95 mg L(-1) at 1-h equilibrium to 0.08 mg L(-1) at 24-h equilibrium for Diphonix and 0.17 mg L(-1) at 1-h equilibrium to 0.03 mg L(-1) at 24-h equilibrium for Chelex-100. Chelex-100 removed more uranium in the first 10 min in the 100mL of acidic-(pH 5)-high-nitrate-containing groundwater ( approximately 5 mg L(-1) uranium); however, after 10 min, Diphonix equaled or out-performed Chelex-100. This study presents an improved understanding of the selectivity and sorption kenetics of a range of ion-exchange resins that remove uranium from both low- and high-nitrate-containing groundwaters with varying pHs.
Phillips
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DH
Environmental Engineering Research Centre, School of Planning, Architecture, and Civil Engineering, Queen's University of Belfast, Belfast BT9 5AG, Northern Ireland, UK. d.phillps@qub.ac.uk
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Watson
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Parmele
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D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007475:Ion Exchange Resins / Q000737:chemistry*; D009566:Nitrates / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry*; D014501:Uranium / Q000737:chemistry*; D014875:Water Pollutants, Radioactive / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D014881:Water Supply
D007475:Ion Exchange Resins; D009566:Nitrates; D012117:Resins, Synthetic; D014875:Water Pollutants, Radioactive; D014501:Uranium