Magnetic modified montmorillonites as potential sorbent phases: characterization and sorption of triazine herbicides

In the present work, montmorillonite (Mt) from two different sources was modified by a one-pot method based on the oxidative polymerization of aniline using Fe₂(SO₄)₃ and magnetite formation by coprecipitation. The magnetic materials were used for the concentration and extraction of six triazine pesticides from aqueous solutions by magnetic solid-phase extraction, and their quantification was done by liquid chromatography–diode array detection. The starting and modified materials were subjected to different characterizations, and the composite formation was confirmed by the modification of the chemical groups present in the mineral phases and their different morphologies. Under optimal sorption conditions, the sorption values obtained for magnetic Mt (MMt) and magnetic Mt-K10 (MMt-K10) were above 80% for all compounds, except hexazinone. The best results were observed for ametryn (96%) on MMt and simazine (95%) on MMt-K10. Based on the results, it can be noted that the low-cost magnetic modified materials demonstrated a very satisfactory sorption of the selected triazines, which present a wide range of polarity. This could allow the development of cheaper analytical methods, with sustainable sorbents, for the quantification of more polar contaminants in aqueous matrices.