Linked Life Data

12026997

Source:http://linkedlifedata.com/resource/pubmed/id/12026997

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2002-5-24
pubmed:abstractText
Entrapped and pooled dense nonaqueous-phase liquids (DNAPLs) often persist in aquifers and serve as a long-term source of groundwater contamination. To address the problematic nature of DNAPL remediation, a surfactant-enhanced aquifer remediation (SEAR) technology, density-modified displacement (DMD), has been developed which significantly reduces the risk of downward migration of displaced DNAPLs. The DMD method is designed to accomplish DNAPL density conversion through the introduction of a partitioning alcohol, n-butanol (BuOH), in a predisplacement flood using conventional horizontal flushing schemes. Subsequent displacement and recovery of the resulting LNAPL is achieved by flushing with a low-interfacial tension surfactant solution. The objective of this study was to investigate density conversion of two representative DNAPLs, chlorobenzene (CB) and trichloroethene (TCE). A series of batch experiments was performed to assess changes in NAPL composition, density, and phase behavior as a function of BuOH mole fraction. Experimental results were used to develop contaminant/BuOH/water ternary phase diagrams and to elucidate regions of contrasting NAPL density. UNIQUAC calculations are presented to support measured compositional and phase behavior data. Density conversion of CB and TCE, relative to water, occurred at NAPL BuOH mole fractions of 0.38 and 0.50, respectively. Significant incorporation of water into the organic phase was observed at relatively high BuOH mole fractions and was shown to limit changes in NAPL composition and density. Interfacial tensions between CB-NAPL and TCE-NAPL and a 6% (by wt) BuOH aqueous solution were found to decrease with increasing NAPL BuOH mole fraction, although in both cases the measured values remained above 2.5 dyn/cm. Total trapping number calculations suggest that, in most aquifer formations, density conversion can be achieved without premature NAPL displacement using a 6% (by wt) BuOH aqueous solution.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0013-936X
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2082-7
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Density-modified displacement for dense nonaqueous-phase liquid source-zone remediation: density conversion using a partitioning alcohol.
pubmed:affiliation
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332-0512, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't