Abstract/Details

Oxidation of humic substances by environmentally friendly oxidants iron(VI) and hydrogen peroxide


2005 2005

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Abstract (summary)

The kinetics of the reactions between humic and fulvic acids (HA and FA) and potassium ferrate were investigated under pseudo order conditions. The rates of HA and FA oxidation with ferrate(VI) were determined at pH 9.0, 25°C. The reactions were found to be first order for each reactant. The oxidation of HA and FA with Fe(VI) occurred by two different pathways allowing for two different pseudo first order rate constants. Rate constant values for an estuarine FA (Mullet Creek) were very similar to those for SRFA (Suwannee River Fulvic Acid) increasing the likelihood that the values are applicable to other natural aqueous systems. The degradation of HA and FA in aqueous solution by means of a photolytic method was also studied. Both FA and HA oxidation by H2O2 followed first-order kinetics for HS (humic substances) and fractional order kinetics for H2O 2, respectively. The optimum H2O2 dose was found to be 86 mM for the oxidation of HS from this study.

The oxidation efficiency of Fe(VI) and oxidation by-products were analyzed by TOC, NMR and GC/MS. The TOC experiments were conducted by measuring organic carbon contents after the oxidation of FA. The results showed that the oxidation of HS by Fe(VI) occurred efficiently and led to 48% mineralization within 30min. The NMR results showed a decrease in aromaticity and carbohydrates after oxidation, and the GC/MS analysis positively identified small carboxylic acid and polycarboxylic acid residues.

The heterogeneous photocatalytic degradation of FA and HA by Fe(VI) with UV/TiO2 was investigated at pH 9.0, 25°C. The oxidation of HS by the Fe(VI) was enhanced by the addition of TiO 2 in the presence of UV light.

Indexing (details)


Subject
Biochemistry;
Biogeochemistry;
Environmental science
Classification
0487: Biochemistry
0425: Biogeochemistry
0768: Environmental science
Identifier / keyword
Health and environmental sciences; Pure sciences; Earth sciences; Environmentally friendly; Humic substances; Hydrogen peroxide; Iron; Oxidation
Title
Oxidation of humic substances by environmentally friendly oxidants iron(VI) and hydrogen peroxide
Author
Lee, Changyoul
Number of pages
129
Publication year
2005
Degree date
2005
School code
0473
Source
DAI-B 66/02, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780496981328, 0496981323
Advisor
Sohn, Mary L.
University/institution
Florida Institute of Technology
University location
United States -- Florida
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3164139
ProQuest document ID
305385963
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305385963
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