Mesoporous phenolic resin and mesoporous carbon for the removal of S-Metolachlor and Bentazon herbicides

Two mesoporous materials, i.e., a mesoporous phenolic resin and a mesoporous carbon, were synthesized following a soft template method to test the removal of two pesticides, Bentazon and S-Metolachlor. The adsorbents were characterized by X-ray diffraction analysis, nitrogen adsorption-desorption isotherms, thermogravimetric analysis, transmission electron microscopy, particle size measurement and XPS spectroscopy. Bentazon and S-Metolachlor adsorption kinetics and isotherm studies were carried out at pH 2 and 4, respectively, on these mesoporous materials as well as on a reference commercial carbon. Freundlich, Langmuir, Dubinin-Raduskevich and Temkin models were applied to describe the adsorption behavior with the Langmuir model showing the best fit. The regeneration of the adsorbents was carried out by calcination under nitrogen atmosphere and the results indicated that the regeneration of the mesoporous carbon was more efficient than that of the mesoporous phenolic resin and the commercial carbon after being reused several times. Another disadvantage of commercial carbon was the great loss of material that it experienced after several adsorption-desorption cycles. (C) 2014 Elsevier B.V. All rights reserved.