Studies On Adsorption Behaviour And Mechanism Of Liuwomijuzhi On Soils

Liuwomijuzhi, which is a new type of insecticide of non-ester oxime aether pyrethroids, has been researched and developed by Hunan Branch of National Southern Pesticide Research and Development Ceter, Hunan Research Institute of Chemical Industry in recent years .Now it has been registered and there is no English name. The pure sample is achromous solids. Its melting point is 27.3-27.1#.The compound is not soluble in water, but it is easily soluble in a majority of organic solvent. Liuwomijuzhi is not only high efficient, quick and broad spectrum, but also low toxic to mammal and safe to plant. Because this compound is new, there is no its studies on aspect of environmental behaviour in the world. This paper studied primely adsorption course and mechanism of Liuwomijuzhi on five soils whose physical and chemical characteristics are different. The major experiment contents and results are as follows:1 This article studied the adsorption course of Liuwomijuzhi on five soils who possess different physical and chemical characteristics , including optimum ratio of water/soil, the time of reaching adsorption equilibrium, the influence of soil pH on adsorption and the isotherm. The result shows that the adsorption strength of Liuwomijuzhi on soils is big (the value of kf is 102.81-187.20 ), the time of reaching equilibrium is short and adsorption is negatively related to soil pH. The adsorption benefit from the reduce of pH and the changes are apparent at pH 4 to 6.2 The adsorption course of Liuwomijuzhi on Clay and Humic acid was researched primely. Adsorption data on Ca-clay and humic acids could fit Freundlich-type equation and the value of kf is 2074.1 and 539.41 respectively. The adsorption on Ca-clay is stronger than on humic acids. Because of interacting Ca-clay with humic acids, adsorption of Liuwomijuzhi on the complex of clay with humic acids was less than clay and humic acids alone. But the interaction is reverse and the active center will be released respectively again after a period of time.3 The interaction mechanisms between Liuwomijuzhi to Ca-clay with humic acids were discussed by means of Fourier transform infrared spectra in this experiment. The results of IR showed that the formation of hydrogen bonds may be the main interaction mechanism.