Naslov
Effects of Temperature on Sorption-Desorption Processes of Imidacloprid in Soils of Croatian Coastal Regions

Autori
Broznić, Dalibor ; Milin, Čedomila

Izvornik
Journal of Environmental Science and Health. Part B : Pesticides, Food Contaminants, and Agricultural Wastes (0360-1234) 47 (2012), 8; 779-794

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
sorption; desorption; imidacloprid; Croatian olive orchard; temperature; hysteresis phenomena

Sažetak
Sorption-desorption behavior of imidacloprid in six soils collected from five coastal regions in Croatia at 20, 30 and 40°C was investigated using batch equilibrium technique. Isothermal data were applied to Freundlich, Langmuir and Temkin equation, and the thermodynamic parameters ΔH°, ΔG°, ΔS° were calculated. The sorption isotherm curves were of non-linear and may be classified as L-type suggesting a relatively high sorption capacity for imidacloprid. Our results showed that the KFsor values decreased for all the tested soils as the temperature increases, indicating that the temperature strongly influence the sorption. Values of ΔG° were negative (-4.65 to -2.00 kJ/mol) indicating that at all experimental temperatures the interactions of imidacloprid with soils were spontaneous process. The negative and small ΔH° values (-19.79 to -8.89 kJ/mol) were in the range of weak forces, such as H-bonds, consistent with interactions and par¬titioning of the imidacloprid molecules into soil organic matter. The ΔS° values followed the range of -57.12 to -14.51 J/molK, suggesting that imidacloprid molecules lose entropy during transition from the solution phase to soil surface. It was found that imidacloprid desorption from soil was concentration and temperature dependent, i.e. at lower imidacloprid concentrations and temperature, lower desorption percentage occurred. Desorption studies revealed that hysteretic behavior under different temperature treatments existed, and it was more pronounced at 20°C in the soils with higher OC content. The study results emphasize the importance of thermodynamic parameters in controling soil pesticide mobility in different geographical locations, seasons and greenhouses condition.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Javno zdravstvo i zdravstvena zaštita, Poljoprivreda (agronomija)

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