Role of bacterial biomass in the sorption of Ni by biomass-birnessite assemblages

Détails

ID Serval
serval:BIB_962FAC3F030E
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Role of bacterial biomass in the sorption of Ni by biomass-birnessite assemblages
Périodique
Environmental Science and Technology
Auteur(s)
Peña J., Bargar J.R., Sposito G.
ISSN
0013-936X
Statut éditorial
Publié
Date de publication
2011
Peer-reviewed
Oui
Volume
45
Pages
7338-7344
Langue
anglais
Résumé
Birnessites precipitated by bacteria are typically poorly crystalline Mn(IV) oxides enmeshed within biofilms to form complex biomass-birnessite assemblages. The strong sorption affinity of bacteriogenic birnessites for environmentally important trace metals is relatively well understood mechanistically, but the role of bacterial cells and extracellular polymeric substances appears to vary among trace metals. To assess the role of biomass definitively, comparison between metal sorption by biomass at high metal loadings in the presence and absence of birnessite is required. We investigated the biomass effect on Ni sorption through laboratory experiments utilizing the birnessite produced by the model bacterium, Pseudomonas putida. Surface excess measurements at pH 6?8 showed that birnessite significantly enhanced Ni sorption at high loadings (up to nearly 4-fold) relative to biomass alone. This apparent large difference in affinity for Ni between the organic and mineral components was confirmed by extended X-ray absorption fine structure spectroscopy, which revealed preferential Ni binding to birnessite cation vacancy sites. At pH >= 7, Ni sorption involved both adsorption and precipitation reactions. Our results thus support the view that the biofilm does not block reactive mineral surface sites; instead, the organic material contributes to metal sorption once high-affinity sites on the mineral are saturated.
Création de la notice
14/10/2011 16:02
Dernière modification de la notice
03/03/2018 19:42
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