Melamine-based organoclay to sequester atrazine

Sequestration of aqueous atrazine by organoclays prepared from the surfactant 6-piperazin-1-yl-N,N'-bis-(1,1,3,3-tetramethyl-butyl)(1,3,5)triazine-2,4-diamine and Gonzales bentonite was assessed using C-14-labeled atrazine. Organoclays with varying ratios of surfactant to clay were evaluated with respect to their ability to sequester atrazine from an aqueous solution. Organoclays containing 100200 g kg(-1) surfactant on a total weight basis provided the most efficient adsorption of atrazine, with apparent K-OC values exceeding 5000 1 kg(-1) at these loading fractions. Less than 12% of sequestered atrazine was released during four sequential daylong washings, supporting our expectation that the majority of the reaction of atrazine with the surfactant lead to irreversible chemical bond formation through nucleophilic aromatic substitution. (c) 2005 Elsevier Ltd. All rights reserved.