The characteristics of adsorptive thermodynamics and kinetics of a new type chelating surfactant named N-lauroylethylenediaminetetriacetate (N-LED3A) on water/soil interface were studied by the batch equilibration method. The effects of pH value, temperature, ionic strength and water-soil ratio on the adsorption behavior of N-LED3A were also investigated. The results showed that pseudo-second order kinetics equation was adapted to describe the adsorption process of N-LED3A on soil, and Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models fitted well to the adsorption behavior. In addition, soil organics and clay minerals played important roles in the adsorption characteristics of N-LED3A on soil. The pH values of solution greatly impacted the adsorption process of N-LED3A on soil as well. As the pH value increased from 5 to 11, the adsorption amount of N-LED3A on soil decreased sharply. Moreover, increasing temperature (from 25℃ to 35℃, and then to 45℃) had little influence on the adsorption amount when N-LED3A concentration was below 1000mg/L. When N-LED3A concentration was higher than 3000mg/L, however, the adsorption amount decreased as the temperature increased. Besides, the adsorption amount of N-LED3A on soil increased with the increasing Na+ ionic strength in solution, and the adsorption amount varied with water-soil ratio in the sequence of (20:1)< (40:1)< (80:1).
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