Abstract/Details

Extraction of pesticide residues in soils using multivariate optimization and supercritical fluid extraction


1996 1996

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Abstract (summary)

Sorption/desorption equilibria and kinetics of atrazine, diuron, and bensulfuron methyl were conducted on several selected soils. The low 1/n$\rm\sb{d}$ (isotherm slope for desorption) values showed that these pesticides were not readily desorbed from the soils tested. The slow rates of desorption were presumably associated with the heterogeneous nature of the soil, and potential hysteresis phenomena. The energy of activation values for both sorption (E$\rm\sb{a}$ = 11-25 kJ/mol) and desorption (E$\rm\sb{d}$ = 18-38 kJ/mol) suggested that transport or diffusion control is rate-limiting for both processes. Pesticide residence time had a major influence on binding extents for all tested pesticides. Extractability as a function of soil composition was greatly dependent on the particular pesticide examined. Effects of supercritical fluid extraction (SFE) parameters on extractability were apparently related to the nature of residues (e.g., freshly fortified versus aged residues), suggesting different desorption mechanisms. Several aged soil samples were extracted by Soxhlet, sonication, surfactant extraction, accelerated solvent extraction (ASE), and SFE for comparison. SFE was the best method to recover aged residues from the soils. Elevated temperature appeared to be a significant factor in effectively recovering aged residues from soils. Prewetting of aged samples was found to be effective in accelerating the extraction rate. Pesticide degradation occurred mostly in soils, but in some cases, it was also observed under laboratory conditions. Degradation basically depended on the characteristics of the pesticide and the nature of the environment.

Indexing (details)


Subject
Agricultural chemicals;
Environmental science;
Analytical chemistry
Classification
0749: Agricultural chemicals
0768: Environmental science
0486: Analytical chemistry
Identifier / keyword
Health and environmental sciences; Pure sciences; atrazine; bensulfuron methyl; diuron
Title
Extraction of pesticide residues in soils using multivariate optimization and supercritical fluid extraction
Author
Zhou, Min Michael
Number of pages
259
Publication year
1996
Degree date
1996
School code
0060
Source
DAI-B 58/01, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
0591271273, 9780591271270
Advisor
Sparks, Donald L.
University/institution
University of Delaware
University location
United States -- Delaware
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
9718795
ProQuest document ID
304292282
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304292282
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