<abstract xmlns="http://www.w3.org/1999/xhtml">The degradation kinetics and sorption characteristics of atrazine and metolachlor in Japanese andisol soil were evaluated using laboratory incubation of soil samples. The water content of the soil was set to field capacity while three different temperatures (5, 25 and 35°C) were considered for the experiment. First order model fitted the degradation kinetics of both herbicides under the investigated temperature range with half-lives ranging from 19.2 to 46.9 days for atrazine and from 23.4 to 66.9 days for metolachlor, respectively. The activation energies (<italic>Ea</italic>) of atrazine and metolachlor calculated using Arhenius equation were 21.47 and 23.91 kJ mol−1, respectively. The soil sorption study was conducted using the batch equilibrium process. The adsorption behaviors of atrazine and metolachlor were investigated using linear, Freundlich and Langmuir isotherms although the linear and Freundlich isotherms gave relatively high correlation coefficient (<italic>R2</italic>) and very low standard error of estimate (<italic>SEE</italic>). The free energy (Δ<italic>G</italic>°) values were in the range −30.6 to −32.0 kJ/mol, and −32.1 to −41.5 kJ/mol for atrazine and metolachlor, respectively. Thermodynamic parameters indicated that the adsorption is spontaneous, endothermic accompanied by increase in entropy. The understanding of atrazine and metolachlor sorption processes is essential to determine the pesticide fate and availability in soil for pest control, biodegradation, runoff and leaching.</abstract>

The degradation kinetics and sorption characteristics of atrazine and metolachlor in Japanese andisol soil were evaluated using laboratory incubation of soil samples. The water content of the soil was set to field capacity while three different temperatures (5, 25 and 35°C) were considered for the experiment. First order model fitted the degradation kinetics of both herbicides under the investigated temperature range with half-lives ranging from 19.2 to 46.9 days for atrazine and from 23.4 to 66.9 days for metolachlor, respectively. The activation energies (Ea) of atrazine and metolachlor calculated using Arhenius equation were 21.47 and 23.91 kJ mol−1, respectively. The soil sorption study was conducted using the batch equilibrium process. The adsorption behaviors of atrazine and metolachlor were investigated using linear, Freundlich and Langmuir isotherms although the linear and Freundlich isotherms gave relatively high correlation coefficient (R2) and very low standard error of estimate (SEE). The free energy (ΔG°) values were in the range −30.6 to −32.0 kJ/mol, and −32.1 to −41.5 kJ/mol for atrazine and metolachlor, respectively. Thermodynamic parameters indicated that the adsorption is spontaneous, endothermic accompanied by increase in entropy. The understanding of atrazine and metolachlor sorption processes is essential to determine the pesticide fate and availability in soil for pest control, biodegradation, runoff and leaching.

Aspect of the degradation and adsorption kinetics of atrazine and metolachlor in andisol soil

Tokyo University of Agricultural and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8581,

Pesticide Residues and Environmental Pollution Department, Central Agricultural Pesticide Laboratory, Agriculture Research Center, Dokki, Giza, 12618,

Hellenic Plant Protection Journal

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The degradation kinetics and sorption characteristics of atrazine and metolachlor in Japanese andisol soil were evaluated using laboratory incubation of soil...

Aspect of the degradation and adsorption kinetics of atrazine and metolachlor in andisol soil

Published Online: Feb 07, 2017

Page range: 1 - 14

Received: Jul 05, 2016

Accepted: Dec 23, 2016

DOI: https://doi.org/10.1515/hppj-2017-0001

Keywords
adsorption isotherm, atrazine, degradation kinetics, metolachlor, temperature

© 2017 P. Jaikaew et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Aspect of the degradation and adsorption kinetics of atrazine and metolachlor in andisol soil

Published Online: Feb 07, 2017

Page range: 1 - 14

Received: Jul 05, 2016

Accepted: Dec 23, 2016

DOI: https://doi.org/10.1515/hppj-2017-0001

Keywordsadsorption isotherm, atrazine, degradation kinetics, metolachlor, temperature

© 2017 P. Jaikaew et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
adsorption isotherm, atrazine, degradation kinetics, metolachlor, temperature