Document Detail


Humic acid aggregation in zero-valent iron systems and its effects on trichloroethylene removal.
MedLine Citation:
PMID:  19327814     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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.
Authors:
Daniel C W Tsang; Nigel J D Graham; Irene M C Lo
Related Documents :
22834224 - Process performance and polyphosphate-accumulating organism-glycogen-accumulating organ...
17126354 - Mass transfer of weak acid in nanometer-sized pores of octadecylsilyl-silica gel.
10371434 - Combinations of etchants, composite resins, and bracket systems: an important choice in...
19774664 - Indispensable structure of solution additives to prevent inactivation of lysozyme for h...
1359904 - Changes in neurotransmitter levels associated with the deficiency of some essential ami...
3240094 - Influence of thiamine and ascorbic acid supplementation on the antidotal efficacy of th...
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    
Affiliation:
Environmental and Water Resources Engineering, Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK. daniel.tsang@canterbury.ac.nz
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Chemical Precipitation
Chromatography, High Pressure Liquid
Humic Substances / analysis*
Hydrophobicity
Iron / chemistry*
Kinetics
Spectroscopy, Fourier Transform Infrared
Time Factors
Trichloroethylene / analysis*
Water Pollutants, Chemical / analysis*
Chemical
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


Previous Document:  Performance of activated carbon and bentonite for adsorption of amoxicillin from wastewater: Mechani...
Next Document:  Upflow anaerobic filter for the degradation of adsorbable organic halides (AOX) from bleach composit...