Removal of Atrazine and Deisopropylatrazine from Water by Montmorillonite-Phosphate Crosslinked Compounds
2000
González-Pradas, E. | Villafranca-Sánchez, M. | Del Rey-Bueno, F. | Ureña-Amate, M. D. | Fernández-Pérez, M.
To assess the potential use of two montmorillonite-(cerium [Ce] or zirconium [Zr]) phosphate crosslinked compounds in removing organic pollutants from water, the adsorption of atrazine (6-chloro-N²-ethyl-N⁴-isopropyl-1,3,5-triazine-2,4-diamine) and one of the major metabolites of atrazine in water, deisopropylatrazine (6-chloro-N⁴-ethyl-1,3,5-triazine-2,4-diamine), has been studied at 25°C using batch experiments. The influence of the presence of 0.01 M KCl in the medium was also investigated for a better understanding of variables affecting the adsorption of these organic compounds. Experimental data points have been fitted to the Langmuir equation, with the results indicating a higher adsorption for deisopropylatrazine than for atrazine on both adsorbents in saline and nonsaline medium. Variation of the uptake of atrazine and the metabolite in the solution of 0.01 M KCl shows an enhanced adsorption of deisopropylatrazine on both samples compared w th that of atrazine. Fourier-transformed infrared (FTIR) spectroscopic studies reveal that at the pH generated by the adsorbents (3.7 and 3.9 for Ce and Zr—montmorillonite compounds, respectively), atrazine and its metabolite interact with the surface of the adsorbents. X-ray diffraction analysis showed that the compounds studied are intercalated into the adsorbents. For the compounds considered, the cerium—montmorillonite adsorbent shows a higher capacity of adsorption compared with zirconium—montmorillonite adsorbent, so it might be particularly useful in removing atrazine and, to a greater extent, deisopropylatrazine from water.
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