Reduction and Accumulation of Gold(III) by Medicago sativa Alfalfa Biomass: X-ray Absorption Spectroscopy, pH, and Temperature Dependence

Autor:	Mark W. Renner, Gerardo Gamez, Irene Cano-Aguilera, Jorge L. Gardea-Torresdey, K.J. Tiemann, K. Dokken, Lars R. Furenlid
Rok vydání:	2000
Předmět:	X-ray absorption spectroscopy Gold cluster Aqueous solution Absorption spectroscopy Chemistry food and beverages Mineralogy Sorption General Chemistry Colloid Adsorption Environmental Chemistry Medicago sativa Nuclear chemistry
Zdroj:	Environmental Science & Technology. 34:4392-4396
ISSN:	1520-5851 0013-936X
DOI:	10.1021/es991325m
Popis:	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(III) 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(III) 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 A at pH 5 and 9.0 ± 1 A 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.
Databáze:	OpenAIRE
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