Performance of three resin-based materials for treating uranium-contaminated groundwater within a PRB

Abstract

Three materials that are designed to treat uranium-contaminated water were investigated.These are a cation exchange resin, IRN77, an anion exchange resin, Varion AP, and a recently developed material called PANSIL (quartz sand coated with 2% amidoxime resin by wt.). The reaction rate, capacity, and effective pH range of the three materials are reported. The capacity and conditional distribution coefficient in neutral, uranyl contaminated synthetic groundwater containing carbonate are also reported. The suitability of each material for treating uraniumcontaminated groundwaters using a permeable reactive barrier approach is then discussed.All three materials react rapidly in the pH range 5-7, reaching equilibrium in less than 4 hours at ~23°C. The unconditioned cation exchange resin removed 8 g UO 2 2+ per kg of resin from neutral synthetic groundwater containing 30 mg/l of UO 2 2+ , but a lower capacity is anticipated in groundwater with either higher ionic strength or lower UO 2 2+ concentrations. It operates by first acidifying the solution, then sorbing UO 2 2+ , and can release UO 2 2+ when its buffering capacity has been exhausted. The anion exchange resin is very effective at removing anionic uranyl carbonate species from solutions with a pH above 5, with good specificity. Up to 50 g/kg of uranium is removed from contaminated groundwater at neutral pH. PANSIL is effective at sequestering cationic and neutral uranyl species from solutions in the pH range 4.5 to 7.5, with very good specificity. The capacity of PANSIL is pH dependent, increasing from about 0.4 g/kg at pH 4.5, to about 1 g/kg at pH 6 and 1.5 g/kg around pH 7.5. In neutral groundwater containing carbonate, both the anion exchange resin and PANSIL exhibit conditional distribution coefficients exceeding 1470 ml/g, which is about an order of magnitude higher than comparable reactive barrier materials reported in the literature.

Literature Survey for Groundwater Treatment Options for Nitrate Iodine-129 and Uranium 200-Zp-1 Operable Unit Hanford Site

“…• (Barton et al 2004) tested three IX resins in column tests to mimic behavior in PRBs with promising results. Another option" likely cheaper, would be to use a mulch barrier as described in the section previously for PRBs used for treatment of nitrate.…”

Application of commercially available anion exchange resins for preconcentration of palladium(II) complexes from chloride–nitrate solutions

“…At present various types of commercially available cation and anion exchangers Varion, are used in preconcentration processess [3,4], water treatment [5][6][7][8][9], removal [7,[10][11][12], purification and separation processes [10,13].…”

Groundwater protection from cadmium contamination by permeable reactive barriers

“…Current research is focused on the use of alternative materials and physical chemical processes for PRBs [11][12][13][14][15][16][17][18][19][20][21][22][23]. Adsorption is a very promising physical process for removing heavy metals and chlorinated solvents from natural and industrial waters [24].…”