INQUISUR   21779
INSTITUTO DE QUIMICA DEL SUR
Unidad Ejecutora - UE
artículos
Título:
Synthesis, characterization and application of a hexagonal mesoporous silica for pesticide removal from aqueous solution
Autor/es:
MAXIMILIANO BRIGANTE; MARCELO AVENA
Revista:
MICROPOROUS AND MESOPOROUS MATERIALS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2014 vol. 191 p. 1 - 9
ISSN:
1387-1811
Resumen:
A hexagonal mesoporous silica (SiO 2 ) was hydrothermally synthesized in alkaline media by using mixed
cationic cetyltrimethylammonium tosylate-non-ionic Pluronic F68 surfactants as template. After
characterization by commonly used techniques, the solid was evaluated as adsorbent for the remotion
of dicationic herbicide paraquat (PQ
2+
). The adsorption of the PQ
2+
on SiO 2 has been studied in batch
experiments by performing adsorption isotherms under different conditions of pH, supporting electrolyte
concentration, and temperature. Adsorption kinetic on the studied material has also been carried out and
discussed. The adsorption of PQ
2+
on the studied material is strongly dependent on pH, increasing as pH
increases. The adsorption seems to take place by direct binding of the cationic herbicide to SiO 2 active
sites (e.g. surface and/or inside the mesopores) through electrostatic interactions and outer-sphere (or
ionic pair) complexes formations, as deduce from adsorption experiments at several ionic strengths
and temperatures. The analysis of thermodynamic parameters suggests that the adsorption of PQ 2+ on the studied solid is exothermic and spontaneous in nature. Even after four regeneration cycles through
acid washing, the mesoporous material has still a removal efficiency of ca. 75%, showing a promising
application for the treatment of wastewater containing paraquat ions.