Linked Life Data

16433357

Source:http://linkedlifedata.com/resource/pubmed/id/16433357

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2006-1-25
pubmed:abstractText
Reductive transformation reactions involving mineral-bound Fe2+ species are of great relevance for the fate of groundwater contaminants. For clay minerals, which are ubiquitously present in soils and sediments, the factors determining the reactivity of structural Fe2+ and surface-bound Fe2+ are not well understood. We investigated the reactivity and availability of Fe2+ species in suspensions of chemically reduced montmorillonite (SAz-1) as well as in suspensions of oxidized and reduced nontronite (SWa-1, ferruginous smectite) using two acetylnitrobenzene isomers as reactive probe compounds. The analyses of the reduction kinetics of the two nitroaromatic compounds (NACs) suggested that Fe2+ bound in the octahedral layer of reduced smectites is the predominant reductant and that electron transfer presumably occurs via basal siloxane planes. In contrast, reduction of NACs by Fe2+ associated with oxidized nontronite is orders of magnitude slower than reduction by octahedral Fe2+. Reductive transformation and reversible, nonreactive electron donor-acceptor (EDA) complexation of NACs at basal smectite surfaces occur simultaneously at reduced montmorillonite exhibiting low structural iron content. In contrast, EDA complexation was not observed in suspensions of reduced iron-rich nontronite. Due to the similar reduction rate constants measured for the two NACs, we propose that the (re)- generation of octahedral Fe2+ sites, e.g., by electron transfer and/or Fe rearrangement within the octahedral nontronite layers, partly limited the rate of contaminant transformation. Since iron in clay minerals is available for microbial reduction, our study suggests that octahedral Fe2+ can contribute to abiotic contaminant transformation in anoxic environments.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0013-936X
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
235-42
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Reduction of nitroaromatic compounds by Fe(II) species associated with iron-rich smectites.
pubmed:affiliation
Swiss Federal Institute of Technology (ETH) and Swiss Federal Institute for Environmental Science and Technology (EAWAG), Universitätsstr. 16, ETH Zentrum, CH-8092 Zürich, Switzerland. thomas.hofstetter@env.ethz.ch
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't