Removal of atrazine from water using covalent sequestration

Abstract

Monochlorotriazines including atrazine and its major metabolites, deethylatrazine and deisopropylatrazine, are susceptible to nucleophilic aromatic substitution. Competitive reactions to rank the relative reactivity of nucleophiles with atrazine reveal that constrained secondary amines are the most reactive. When the nucleophile is attached to a solid support, atrazine can be sequestered from solution. As proof of concept, polystyrene resins displaying constrained secondary amines are shown to sequester atrazine, deethylatrazine, and deisopropylatrazine from water. Sequestration can be followed spectrophotometrically or using a liquid chromatography mass spectrometry protocol. The kinetics of sequestration are similar to that of granulated charcoal. Evidence for covalent bond formation comes from control experiments with unreactive herbicides and degradation analysis of the solid support. Using both (1)H NMR spectroscopy and mass spectrometry, covalent adducts are identified in ratios close to what is calculated theoretically. This method for sequestration is effective at removing atrazine from pond water.