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Fig. 2. Scheme of 2,4-D adsorption on soils. A: 2,4-D adsorption on active surface hydroxyls of metal (hydr)oxides by an ion exchange reaction (electrostatic interaction). B: 2,4-D adsorption on metal (hydr)oxides by a ligand exchange reaction which replaces an active surface hydroxyl with a carboxyl group of 2,4-D molecule, forming a strong coordination bond. C: 2,4-D adsorption on metal-humate complexes by a ligand exchange reaction. M denotes metals such as Al and Fe.
