Boehmite sorbs perrhenate and pertechnetate

Abstract

Boehmite and Al-oxyhydroxide gels sorb ReO4 -, a non-radioactive analogue of TcO4 - from NaNO3 solutions. Sorption appears to be substantially electrostatic (though there appears to be a specific preference for ReO4 - over NO3 -) and is most effective at pH < 8. Measured Kd´s lie between 5 and 105 ml g-1, depending on the solid, pH, and ionic strength. ReO4 - and TcO4 - are both partially removed from high pH Hanford-type acid waste simulants upon neutralization and formation of Al-rich sludges. We therefore propose that sequestration of Tc by boehmite limits dissolved Tc levels in the near and sub-surface environment and for that purpose boehmite might be relied on as a backfill, or reactive barrier, to limit environmental transport of Tc.