Adsorption and desorption behavior of herbicide diuron on various Chinese cultivated soils.
The adsorption-desorption behaviors of diuron were investigated in six cultivated soils of China. The effect of system pH and temperature were also studied. The data fitted the Freundlich equation very well. The adsorption K(F) values indicated the adsorption of diuron in the six soils was in the sequence of black soil (D)>yellow earth (F)>paddy soil (B)>yellow-brown soil (C)>yellow-cinnamon soil (A)>lateritic red earth (E). The adsorption K(F) and Freundlich exponents n were decreased when temperature was increased from 298 K to 318 K. However, the Gibb's free energy values were found less negative with the increasing temperature. Meanwhile, the extent of diuron adsorption on soil was at rather high level under low pH value conditions and decreased with increasing pH value. In addition, the desorption behavior of diuron in the six soils was in the sequence of lateritic red earth (E)>yellow-cinnamon soil (A)>paddy soil (B)>yellow earth (F)>yellow-brown soil (C)>black soil (D). At the same time, desorption hysteresis of diuron were observed in all of the tested soils. And the soil organic matter content may play an important role in the adsorption-desorption behavior.
Liu
Yihua
Y
Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China.
Xu
Zhenzhen
Z
Wu
Xiaoguang
X
Gui
Wenjun
W
Zhu
Guonian
G
D000327:Adsorption; D000383:Agriculture; D000465:Algorithms; D002681:China; D002851:Chromatography, High Pressure Liquid; D004237:Diuron / Q000737:chemistry*; D006540:Herbicides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007474:Ion Exchange; D007700:Kinetics; D018570:Risk Assessment; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
D006540:Herbicides; D012987:Soil; D012989:Soil Pollutants; D004237:Diuron