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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-2-12
pubmed:abstractText
The effect of pH and rhamnolipids on the solubility of phenanthrene was investigated in a sand-water system. Batch phenanthrene solubilization experiments in this system showed that the highest phenanthrene solubility occurred at pH 5 in the presence of 240 and 150 mg L(-1) rhamnolipids. As the pH was increased from 5 to 7, the apparent solubility of phenanthrene decreased and then stabilized from pH 7 to 8. At pH 4, a dramatic decrease in phenanthrene solubility was observed. This result is in contrast to previous findings obtained in an aqueous system without soil particles. To investigate the reason for this decrease, the critical micelle concentrations (CMCs) were measured in the presence or absence of sand particles, and the maximum amount of sorbed biosurfactant at each pH was calculated based on the differences of the two CMC values. More rhamnolipid molecules were lost by the sorption into sand particles at pH 4 than at other pH values; this explains the dramatic decrease of solubility at pH 4 in the sand-water system. To confirm the explanation for the different solubilizing capacity that results from the structural change of biosurfactant aggregate, cryo-transmission electron microscopy was used. Micrographs showed that the rhamnolipid morphology changed from large lamellar sheets, to vesicle, and then to micelle as the pH increased. The large and multilamellar vesicles at pH 5 were considered to be the most effective structure for the solubilization of phenanthrene.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0047-2425
pubmed:author
pubmed:issnType
Print
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
509-14
pubmed:meshHeading
pubmed:articleTitle
Rhamnolipid morphology and phenanthrene solubility at different pH values.
pubmed:affiliation
Dep. of Environmental Science and Engineering, Gwangju Inst. of Science and Technology, Gwangju, Korea.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't