Adsorption-desorption behavior of acetochlor to soils in the presence of some environmental substances

Article type: Research Article

Authors: Ye, Chang-ming | Lei, Zhi-fang

Affiliations: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. E-mail: [email protected]

Abstract: The behavior of herbicide acetochlor adsorption-desorption to soil in the presence of humic acid (HA), anionic surfactant sodium dodecylbenzene sulfonate (SDBS), cationic surfactant hexadecyltrimethyl-ammonium bromide (HDAB) and NH_4NO_3 as a chemical fertilizer was studied. Observed acetochlor adsorption isotherm were well described using Freundlich isotherm equation, from which the desorption isotherm equation has been deduced. The deduced equation can more directly describe acetochlor desorption process. The results showed that the enhance of acetochlor adsorption capacity by solid HA was greater than by soluble HA. The presence of NH_4 NO_3 can slightly enhance acetochlor adsorption to soil by comparison with that measured in NH_4NO_3-free solution. In soil-water system, surfactant-acetochlor interaction is very complex, and the surfactant adsorptions as well as acetochlor adsorption need to be considered. When acetochlor-soil suspensions contained lower concentration SDBS or HDAB (40 mg/L), K_f for acetochlor adsorption was decreased in comparison to that measured in SDBSor HDAB-free solution. When acetochlor-soil suspensions contained higher concentration SDBS or HDAB (corresponding 1400 mg/L or 200 mg/L), K_f for acetochlor adsorption was increased in comparison to that measured in SDBS- or HDAB-free solution.

Keywords: adsorption-desorption, acetochlor, humid acid, surfactants, ammonium nitrate, soil

Journal: Journal of Environmental Sciences, vol. 14, no. 2, pp. 269-276, 2002