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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pignatello, J. J. Articles by Baehr, K. Search for Related Content PubMed Articles by Pignatello, J. J. Articles by Baehr, K. Agricola Articles by Pignatello, J. J. Articles by Baehr, K.

Ferric Complexes as Catalysts for "Fenton" Degradation of 2,4-D and Metolachlor in Soil

Dep. of Soil and Water, The Connecticut Agric. Exp. Stn., P.O. Box 1106, New Haven, CT 06504;

Katharina Baehr

Institüt für Bodenkunde und Standortslehre, Bodenchemie (Nr. 310), Universität Hohenheim, 7000 Stuttgart 70, Federal Republic of Germany.

^* Corresponding author.

ABSTRACT

Fenton-type reactions of hydrogen peroxide with Fe compounds generate hydroxyl radical (OH-) or other reactive species and are potentially useful for degrading organic contaminants in soil. The use of simple Fe salts is limited, however. This study investigated certain pH 6-soluble Fe(III) complexes (Fe-L, where L is an organic ligand) as catalysts for degradation of herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and metolachor (2-chloro-N-[2-ethyl-6-methylphenyl]-N-[2-methoxy-1-methylethyl]acetamide). Reactions were carried out in 1:1 aqueous suspensions of a topsoil (15.7 g kg^–1 organic C) at the natural pH of 5.7 with herbicides at concentrations representative of a spill (2–3 g kg^–1, about 0.01 mol kg^–1). The two herbicides had contrasting sorption behavior in that 2,4-D was mostly in solution, whereas metolachlor was mostly sorbed. The best results were obtained using Fe-nitrilotriacetate (NTA) or Fehydroxyethyleniminodiacetate (HEIDA) at 0.01 mol kg^–1 and [H₂O₂] 0.5 mol kg^–1. The gallic acid complex was less effective. In 3 h, ¹⁴C-labeled 2,4-D was quantitatively dechlorinated and partially (15–30%) converted to ¹⁴CO₂: metolachlor was 93% transformed and 29% dechlorinated. Controls using free ligand plus peroxide or peroxide alone gave little or no reaction. Fe-L + H₂O₂ was superior to the Fenton reagent itself (Fe²⁺ + H₂O₂). The results of this study demonstrate that relatively mild chemical oxidation can be effective for remediation of certain contaminants in soil.

This article has been cited by other articles:

				Q. Wang and A. T. Lemley Kinetic Effect of Humic Acid on Alachlor Degradation by Anodic Fenton Treatment J. Environ. Qual., November 1, 2004; 33(6): 2343 - 2352. [Abstract] [Full Text] [PDF]

				H.M. Gaber, S.D. Comfort, P.J. Shea, and T.A. Machacek Metolachlor Dechlorination by Zerovalent Iron during Unsaturated Transport J. Environ. Qual., May 1, 2002; 31(3): 962 - 969. [Abstract] [Full Text] [PDF]

				S. A. Benner, K. G. Devine, L. N. Matveeva, and D. H. Powell From the Cover: The missing organic molecules on Mars PNAS, March 14, 2000; 97(6): 2425 - 2430. [Abstract] [Full Text] [PDF]