Titre
Role of bacterial biomass in the sorption of Ni by biomass-birnessite assemblages
Type
article
Institution
UNIL/CHUV/Unisanté + institutions partenaires
Périodique
Auteur(s)
Peña, J.
Auteure/Auteur
Bargar, J.R.
Auteure/Auteur
Sposito, G.
Auteure/Auteur
Liens vers les personnes
Liens vers les unités
ISSN
0013-936X
Statut éditorial
Publié
Date de publication
2011
Volume
45
Première page
7338
Dernière page/numéro d’article
7344
Peer-reviewed
Oui
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.
PID Serval
serval:BIB_962FAC3F030E
Date de création
2011-10-14T14:02:58.021Z
Date de création dans IRIS
2025-05-20T22:39:54Z