Document Detail

Humic acid aggregation in zero-valent iron systems and its effects on trichloroethylene removal.
MedLine Citation:
PMID:  19327814     Owner:  NLM     Status:  MEDLINE    
The influence of natural organic matter on contaminant removal by Fe(0) systems has been of increasing concern. Recent studies have shown that, in addition to direct sorption on the Fe(0) surfaces, humic acid complexation with dissolved iron released from corrosion results in the formation of colloids and aggregates in solution that may affect contaminant removal. High-pressure size-exclusion chromatographic analyses revealed increasing molecular weights of dissolved humic acids with reaction time. Humic acid aggregation occurred across a wide range of molecular weight fractions. Fourier transform infrared spectroscopic analysis of humic acid aggregates suggested the presence of inner-sphere complexation involving different oxygen-containing functional groups; hydrophobic interactions also probably contributed to aggregation as the humic acid of more aromatic and hydrophobic character was aggregated at a faster rate. Because of multiple underlying processes, a variety of cross-correlated physicochemical properties of humic acids contributed to their aggregation. The presence of humic acid aggregates provided an additional hydrophobic domain for partitioning that enhanced trichloroethylene removal, although steric blocking of the Fe(0) surfaces may inhibit its reduction to some extent. Comparable effects were demonstrated for various types of humic acids.
Daniel C W Tsang; Nigel J D Graham; Irene M C Lo
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-03-26
Journal Detail:
Title:  Chemosphere     Volume:  75     ISSN:  1879-1298     ISO Abbreviation:  Chemosphere     Publication Date:  2009 Jun 
Date Detail:
Created Date:  2009-05-04     Completed Date:  2009-06-18     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0320657     Medline TA:  Chemosphere     Country:  England    
Other Details:
Languages:  eng     Pagination:  1338-43     Citation Subset:  IM    
Environmental and Water Resources Engineering, Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK.
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MeSH Terms
Chemical Precipitation
Chromatography, High Pressure Liquid
Humic Substances / analysis*
Iron / chemistry*
Spectroscopy, Fourier Transform Infrared
Time Factors
Trichloroethylene / analysis*
Water Pollutants, Chemical / analysis*
Reg. No./Substance:
0/Humic Substances; 0/Water Pollutants, Chemical; 7439-89-6/Iron; 79-01-6/Trichloroethylene

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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