Effects of Simulated Rare Earth Recycling Wastewaters on Biological Nitrification.

Environmental science & technology (2015-07-02)
Yoshiko Fujita, Joni Barnes, Ali Eslamimanesh, Malgorzata M Lencka, Andrzej Anderko, Richard E Riman, Alexandra Navrotsky
RESUMO

Increasing rare earth element (REE) supplies by recycling and expanded ore processing will result in generation of new wastewaters. In some cases, disposal to a sewage treatment plant may be favored, but plant performance must be maintained. To assess the potential effects of such wastewaters on biological treatment, model nitrifying organisms Nitrosomonas europaea and Nitrobacter winogradskyi were exposed to simulated wastewaters containing varying levels of yttrium or europium (10, 50, and 100 ppm), and the extractant tributyl phosphate (TBP, at 0.1 g/L). Y and Eu additions at 50 and 100 ppm inhibited N. europaea, even when virtually all of the REE was insoluble. Provision of TBP with Eu increased N. europaea inhibition, although TBP alone did not substantially alter activity. For N. winogradskyi cultures, Eu or Y additions at all tested levels induced significant inhibition, and nitrification shut down completely with TBP addition. REE solubility was calculated using the previously developed MSE (Mixed-Solvent Electrolyte) thermodynamic model. The model calculations reveal a strong pH dependence of solubility, typically controlled by the precipitation of REE hydroxides but also likely affected by the formation of unknown phosphate phases, which determined aqueous concentrations experienced by the microorganisms.

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Sigma-Aldrich
Tributyl phosphate, ≥99%
Sigma-Aldrich
Tributyl phosphate, 97%
Sigma-Aldrich
Europium(III) chloride, anhydrous, powder, 99.99% trace metals basis
Sigma-Aldrich
Yttrium, powder, −40 mesh, 99.5% trace rare earth metals basis
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Yttrium, chips, 99.9% trace rare earth metals basis
Sigma-Aldrich
Europium(III) chloride, powder, ≥99.9% trace metals basis
Yttrium, foil, not light tested, 25x25mm, thickness 0.005mm, as rolled, 99%
Yttrium, rod, 100mm, diameter 6.35mm, cast, 99%
Yttrium, rod, 50mm, diameter 12.5mm, cast, 99%
Yttrium, rod, 50mm, diameter 2.0mm, cast, 99%
Yttrium, rod, 50mm, diameter 6.35mm, cast, 99%
Yttrium, wire reel, 0.05m, diameter 0.5mm, 99.9%
Yttrium, wire reel, 0.05m, diameter 1.0mm, 99.9%
Yttrium, wire reel, 0.05m, diameter 1.0mm, square section, 99.9%
Yttrium, wire reel, 0.1m, diameter 0.5mm, 99.9%
Yttrium, wire reel, 0.1m, diameter 1.0mm, 99.9%
Yttrium, wire reel, 0.2m, diameter 0.5mm, 99.9%
Yttrium, wire reel, 0.2m, diameter 1.0mm, 99.9%
Yttrium, foil, 25x25mm, thickness 0.125mm, as rolled, 99%
Yttrium, foil, 25x25mm, thickness 0.15mm, as rolled, 99%
Yttrium, foil, 50x50mm, thickness 0.125mm, as rolled, 99%
Yttrium, foil, 50x50mm, thickness 0.15mm, as rolled, 99%
Yttrium, foil, 25mm disks, thickness 0.50mm, as rolled, 99%
Yttrium, foil, not light tested, 100x100mm, thickness 0.025mm, as rolled, 99%
Yttrium, foil, not light tested, 25x25mm, thickness 0.025mm, as rolled, 99%
Yttrium, foil, not light tested, 50x50mm, thickness 0.025mm, as rolled, 99%
Yttrium, rod, 100mm, diameter 12.5mm, cast, 99%
Sigma-Aldrich
Yttrium sputtering target, diam. × thickness 2.00 in. × 0.25 in., 99.9% trace metals basis
Sigma-Aldrich
Yttrium, ingot, 99.9% trace rare earth metals basis