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 Xue, S. K. Articles by Selim, H. M. Search for Related Content PubMed Articles by Xue, S. K. Articles by Selim, H. M. Agricola Articles by Xue, S. K. Articles by Selim, H. M.

Modeling Adsorption-Desorption Kinetics of Alachlor in a Typic Fragiudalf

Agronomy Dep., Sturgis Hall, Louisiana State Univ., Baton Rouge, LA 70803.

^* Corresponding author (xp2469{at}lsuvm.sncc.lsu.edu).

ABSTRACT

Adsorption and desorption kinetics are essential components for modeling the fate of pesticides in soils. This study was conducted to characterize the kinetics of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide] adsorption and desorption in Gigger (fine-silty, mixed, thermic Typic Fragiudalf) surface soil samples collected from long term no-till and conventional tillage plots. A batch method was used to determine alachlor adsorption with time up to 528 h for a range of input concentrations from 0.5 to 50 mg/L. Successive dilution was used to quantify desorption kinetics following 16, 32, 64, 128, 256, and 512 h of adsorption. For both samples, alachlor time-dependent results indicated initially fast adsorption followed by slow adsorption where kinetic reactions appeared dominant. Adsorption-desorption showed extensive hysteretic behavior resulting from discrepancies between adsorption and desorption isotherms. Hysteresis was more pronounced with increased reaction time of adsorption. Four variations of a nonlinear multireaction kinetic model successfully described retention results. Adsorption and desorption, however, were best described by a model version incorporating nonlinear equilibrium, a kinetic reversible mechanism, and a consecutive irreversible mechanism. The model was successfully used in describing alachlor adsorption and desorption results. The model predicted the overall alachlor hysteresis satisfactorily except that, at large times, desorption isotherms were not considered adequate. The model also was capable of predicting alachlor desorption kinetics based solely on parameters obtained from adsorption experiments.

Manuscript no. 95-09-9030 of the Louisiana Agric. Exp. Stn.

Received for publication October 19, 1994.

This article has been cited by other articles:

				M. Sander, Y. Lu, and J. J. Pignatello A Thermodynamically Based Method to Quantify True Sorption Hysteresis J. Environ. Qual., May 11, 2005; 34(3): 1063 - 1072. [Abstract] [Full Text] [PDF]

				K. Saffih-Hdadi, L. Bruckler, and E. Barriuso Modeling of Sorption and Biodegradation of Parathion and Its Metabolite Paraoxon in Soil J. Environ. Qual., November 1, 2003; 32(6): 2207 - 2215. [Abstract] [Full Text] [PDF]

				H. M. Selim, L. Zhou, and H. Zhu Herbicide Retention in Soil as Affected by Sugarcane Mulch Residue J. Environ. Qual., July 1, 2003; 32(4): 1445 - 1454. [Abstract] [Full Text] [PDF]

				H. M. Selim Retention and Runoff Losses of Atrazine and Metribuzin in Soil J. Environ. Qual., May 1, 2003; 32(3): 1058 - 1071. [Abstract] [Full Text] [PDF]

				H. M. Selim, L. Zhou, and S. K. Xue Alachlor Transport during Transient Water Flow in Unsaturated Soils Soil Sci. Soc. Am. J., November 1, 2002; 66(6): 1773 - 1783. [Abstract] [Full Text] [PDF]

				R. Celis and W. C. Koskinen Characterization of Pesticide Desorption from Soil by the Isotopic Exchange Technique Soil Sci. Soc. Am. J., November 1, 1999; 63(6): 1659 - 1666. [Abstract] [Full Text] [PDF]

				H.M. Selim, L. Ma, and H. Zhu Predicting Solute Transport in Soils: Second-Order Two-Site Models Soil Sci. Soc. Am. J., July 1, 1999; 63(4): 768 - 777. [Abstract] [Full Text]