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Treatment of Pertechnetate (TcO4-)-Contaminated Groundwater |
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Breakthrough
of pertechnetate (TcO4-) on a bifunctional
RO-02-119 resin column in
a field experiment at the Paducah Gaseous Diffusion Plant site, |
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Less than 3% TcO4- breakthrough observed after treatment of ~700,000 bed volumes of groundwater. |
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Pertechnetate (TcO4-) – an analog to perchlorate (ClO4-). |
This
study evaluated a new class of bifunctional anion-exchange
resins developed at the Oak Ridge National Laboratory for removing
pertechnetate (TcO4-) from contaminated groundwater.
Both laboratory-column and field flow-through
experiments were performed, and results indicated that superior
performance of the bifunctional resins has been achieved through the use
of two quaternary ammonium groups, one
having long chains (trihexylamine) for higher selectivity for poorly
hydrated large anions and one having shorter chains (triethylamine) for
enhanced kinetics and exchange capacity.
Field results indicated that the bifunctional resin performed
much better than one of the best commercial monofunctional anion-exchange
resins (e.g., Puroliteâ
A-520E) with respect to the removal of TcO4- from
contaminated groundwater (with improved selectivity and sorption
kinetics).
Less than 3% of TcO4- breakthrough was
observed after ~700,000 bed volumes (BV) of contaminated groundwater had
been treated by the bifunctional resin column at the U.S. Department of
Energy's Paducah Gaseous Diffusion Plant site.
The results demonstrate that the new resin is particularly
effective in removing low levels of TcO4- (e.g., at
influent concentration of ~0.07 mg/L or ~0.7
nmol/L Tc), and a cost saving may be realized by using the bifunctional
resins for the treatment of large quantities of contaminated groundwater
because of its increased selectivity, treatment efficiency, and longevity.
The new resin may also be applied for the efficient treatment of
other poorly hydrated large anions such as perchlorate (ClO4-)
from contaminated groundwater or surface water.
