Abstract
We report herein the use of Medicago sativa alfalfa shoot biomass for
the removal of gold from aqueous solutions. The accumulation process
involves the reduction of Au(lll) to colloidal Au(0) and is shown to
increase at elevated temperatures and at lower pH. X-ray absorption
spectroscopy (XAS) was used to determine that gold(lll) was reduced to
form gold(0) colloids, which varied in size depending on the pH of the
initial solution. The gold cluster radius was 6.2 +/- 1 Angstrom at pH 5
and 9.0 +/- 1 Angstrom at pH 2. Our findings indicate that essentially
another layer of gold atoms was deposited onto the colloid surface at pH
2. Possible mechanisms of bioreduction and accumulation are discussed.
Original language | English |
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Pages (from-to) | 4392-4396 |
Journal | Environmental Science & Technology |
State | Published - Oct 2000 |