Montmorillonite-chitosan bionanocomposites as adsorbents of the herbicide clopyralid in aqueous solution and soil/water suspensions

► Montmorillonite-chitosan bionanocomposites were prepared using different methodologies. ► The samples were characterized and tested as adsorbents of the anionic herbicide clopyralid. ► The bionanocomposites were effective in adsorbing clopyralid at mild acidic conditions. ► The samples showed potential as adsorbents to remove and immobilize anionic pesticides in soil and water systems.