MOHAMAD FAKIH , XAVIER CHÂTELLIER, MÉLANIE DAVRANCHE AND ALINE DIA
Environ. Sci. Technol. 2008, 42, 3194–3200
University of Rennes 1, CNRS, Géosciences Rennes, UMR 6118, Avenue du Général Leclerc, 35042 Rennes Cedex, France
Bacteria are known to associate closely with secondary iron oxides in natural environments, but it is still unclear whether they catalyze their precipitation. Here, Fe2+ ions were progressively added to various concentrations of Bacillus subtilis bacteria in permanently oxic conditions while maintaining the pH at 6.5 by adding a NaOH solution at a monitored rate. The iron/ bacteria precipitates were characterized by wet chemistry, SEM, and XRD. Abiotic syntheses produced nanolepidocrocite, and their kinetics displayed a strong autocatalytic effect.
Biotic syntheses led to the formation of tiny and poorly crystallized particles at intermediate bacterial concentrations and to a complete inhibition of particle formation at high bacterial concentrations. The occurrence of the autocatalytic effect was delayed and its intensity was reduced. Both
Biotic syntheses led to the formation of tiny and poorly crystallized particles at intermediate bacterial concentrations and to a complete inhibition of particle formation at high bacterial concentrations. The occurrence of the autocatalytic effect was delayed and its intensity was reduced. Both
Aucun commentaire:
Enregistrer un commentaire