Atrazine adsorption desorption behavior in Darehasaluie Kavar corn field soil in Fars province of Iran

ABSTRACT

Adsorption desorption behaviors of widely applied atrazine soil were studied, employing a batch technique as a case study in Darehasaluie Kavar corn field in Fars Province in 2005. Samples were collected into 0 to 20 cm soil depth, where was cultivated under a crop rotation [corn-wheat] during the past 10 years. Sorption kinetics exhibited two phenomena an immediate rapid sorption [1.31 microg/g soil after 12 hours] followed by a slow sorption process [1.37 microg/g soil after 24 hours]. Desorption behavior of atrazine was similar to its adsorption, but at a very slower rate. Atrazine desorption efficiencies were much less effective and incomplete even after a long equilibration time [only 9.16% after 96 hours]. The adsorption-desorption rate for most of the time was positively related to the amount of applied atrazine and the time required for equilibration [P<0.01]. Desorption data exhibited hysteresis phenomena. Atrazine adsorption data described well according to Freundlich [r2=0.95], Langmuir [r2=0.82] and Temkin [r2=0.84] isotherms. However, the fit to Freundlich adsorption model in a non linear form [1/n <1] was closer than the others. Desorption isotherm could be well described by the Temkin [r2=0.96] and Freundlich [r2=0.92] isotherms, but the fit to Temkin model was closer than that of Freundlich