Re deposition is generally thought to involve reduction.  Unfortunately, the pathway to Re removal remains unclear.  Authors purport Re sequestration begins in suboxic (absence of oxygen and sulfide) environments; others produce evidence supporting removal under anoxic (presence of sulfide) conditions.  This research aims to clarify such issues by positing a plausible pathway to Re fixation in suboxic sediments.  While reduction of Tc(VII) is known to be strongly favored in the presence of alumina-sorbed Fe(II), analogous behavior for Re(VII) has not been established.  Preliminary glovebox experiments involve reacting 10 �M ReO4- at pH=7.0 in the presence of 100 �M Fe(II), hydrated d-alumina, or hydrated d-alumina previously exposed to  100 �M Fe(II).  At various times, aliquots of test solutions are filtered (0.45 �m) and ReO4- quantified using reverse phase ion pair chromatography with suppressed conductivity detection.  For comparison, similar experiments involving Mo(VI) (MoO42-) will also be performed and presented.

Re(VII) reduction in the presence of sorbed Fe(II): Plausible removal pathway in suboxic porewaters

245th National Meeting (2013)

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