HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Related articles in JEQ Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (14) Citing Articles via Google Scholar Google Scholar Articles by Satapanajaru, T. Articles by Shea, P. J. Search for Related Content PubMed PubMed Citation Articles by Satapanajaru, T. Articles by Shea, P. J. Agricola Articles by Satapanajaru, T. Articles by Shea, P. J. Related Collections Remediation Organic Compounds Agricultural Pesticides Soil Pollution

TECHNICAL REPORTS

Organic Compounds in the Environment

Enhancing Metolachlor Destruction Rates with Aluminum and Iron Salts during Zerovalent Iron Treatment

^a Department of Environmental Science, Kasetsart University, Bangkok, Thailand 10900
^b School of Natural Resources, University of Nebraska-Lincoln, 256 Keim Hall, Lincoln, NE 68583-0915

^* Corresponding author (scomfort{at}unl.edu).

Received for publication September 19, 2002. Pesticide-contaminated soil may require remediation to mitigate ground and surface water contamination. We determined the effectiveness of zerovalent iron (Fe⁰) to dechlorinate metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methyl ethyl) acetamide] in the presence of aluminum and iron salts. By treating aqueous solutions of metolachlor with Fe⁰, we found destruction kinetics were greatly enhanced when Al, Fe(II), or Fe(III) salts were added, with the following order of destruction kinetics observed: Al₂(SO₄)₃ > AlCl₃ > Fe₂(SO₄)₃ > FeCl₃. A common observation was the formation of green rusts, mixed Fe(II)–Fe(III) hydroxides with interlayer anions that impart a greenish-blue color. Central to the mechanism responsible for enhanced metolachlor loss may be the role these salts play in facilitating Fe(II) release. By tracking Al and Fe(II) in a Fe⁰ + Al₂(SO₄)₃ treatment of metolachlor, we observed that Al was readily sorbed by the corroding iron with a corresponding release of Fe(II). The manufacturing process used to produce the Fe⁰ also profoundly affected destruction rates. Metolachlor destruction rates with salt-amended Fe⁰ were greater with annealed iron (indirectly heated under a reducing atmosphere) than unannealed iron. Moreover, the optimum pH for metolachlor dechlorination in water and soil differed between iron sources (pH 3 for unannealed, pH 5 for annealed). Our results indicate that metolachlor destruction by Fe⁰ treatment may be enhanced by adding Fe or Al salts and creating pH and redox conditions favoring the formation of green rusts.

Abbreviations: HPLC, high performance liquid chromatography • GR, green rusts • SEM, scanning electron microscopy

Related articles in JEQ:

This Issue in Journal of Environmental Quality

JEQ 2003 32: 1577-1582. [Full Text]  

This article has been cited by other articles:

				T. Lee and C. H. Benson Sorption and Degradation of Alachlor and Metolachlor in Ground Water Using Green Sands J. Environ. Qual., September 1, 2004; 33(5): 1682 - 1693. [Abstract] [Full Text] [PDF]

				J. Park, S. D. Comfort, P. J. Shea, and T. A. Machacek Remediating Munitions-Contaminated Soil with Zerovalent Iron and Cationic Surfactants J. Environ. Qual., July 1, 2004; 33(4): 1305 - 1313. [Abstract] [Full Text] [PDF]