Effect of surfactants on sorption of atrazine by soil

This study investigates the effect of synthetic wastewater containing surfa ctants on the sorption of atrazine using an equilibrium batch technique. La boratory experiments were conducted on three soils with two non-ionic (Rexo l and Rexonic) surfactants and one anionic (Sulphonic) surfactant, specific ally manufactured for the detergent industry. Four sets of experiments were conducted to examine the influence of surfactants on the equilibrium time of atrazine sorption, to explore the effect of surfactant concentration, pH and type of surfactant on the amount of atrazine sorbed and to determine s orption isotherms of atrazine in the presence of surfactants. The results i ndicate that the application of Sulphonic results in dramatic increase in t he adsorption of atrazine on to soils, the increase being directly proporti onal to the concentration of the surfactant. Application of the Sulphonic s urfactants with a concentration of 3000 mg/l can result in a significant in crease in K-d values of atrazine for loam and sandy loam soils. On the othe r hand, the effect of non-ionic surfactants depends on their concentration, Generally, non-ionic surfactants can result in a slight increase in atrazi ne sorption at high concentration, an exception being Rexol on sandy loam s oil. At low concentrations, non-ionic surfactants have shown a tendency to decrease atrazine sorption. (C) 1999 Published by Elsevier Science B.V, All rights reserved.