Linked Life Data

21193215

Source:http://linkedlifedata.com/resource/pubmed/id/21193215

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2011-1-17
pubmed:abstractText
Although numerous studies have been conducted to discern colloid transport and stability processes, the mechanistic understanding of how dissolved organic matter (DOM) affects colloid fate in unsaturated soils (i.e., the vadose zone) remains unclear. This study aims to bridge the gap between the physicochemical responses of colloid complexes and porous media interfaces to solution chemistry, and the effect these changes have on colloid transport and fate. Measurements of adsorbed layer thickness, density, and charge of DOM-colloid complexes and transport experiments with tandem internal process visualization were conducted for key constituents of DOM, humic (HA) and fulvic acids (FA), at acidic, neutral and basic pH and two CaCl(2) concentrations. Polymeric characteristics reveal that, of the two tested DOM constituents, only HA electrosterically stabilizes colloids. This stabilization is highly dependent on solution pH which controls DOM polymer adsorption affinity, and on the presence of Ca(+2) which promotes charge neutralization and inter-particle bridging. Transport experiments indicate that HA improved colloid transport significantly, while FA only marginally affected transport despite having a large effect on particle charge. A transport model with deposition and pore-exclusion parameters fit experimental breakthrough curves well. Trends in deposition coefficients are correlated to the changes in colloid surface potential for bare colloids, but must include adsorbed layer thickness and density for sterically stabilized colloids. Additionally, internal process observations with bright field microscopy reveal that, under optimal conditions for retention, experiments with FA or no DOM promoted colloid retention at solid-water interfaces, while experiments with HA enhanced colloid retention at air-water interfaces, presumably due to partitioning of HA at the air-water interface and/or increased hydrophobic characteristics of HA-colloid complexes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1879-2448
pubmed:author
pubmed:copyrightInfo
© 2010 Elsevier Ltd. All rights reserved.
pubmed:issnType
Electronic
pubmed:volume
45
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1691-701
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Impact of dissolved organic matter on colloid transport in the vadose zone: deterministic approximation of transport deposition coefficients from polymeric coating characteristics.
pubmed:affiliation
Department of Biological and Environmental Engineering, Riley-Robb Hall, Cornell University, Ithaca, NY 14853-5701, USA. VLM8@cornell.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't