INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Adsorption of glyphosate on modfied zeolitas
Autor/es:
A. TRINELLI; E. CHMIELEWSKÁ; M. DOS SANTOS AFONSO
Lugar:
Mar del Plata, Argentina
Reunión:
Congreso; V Congreso Iberoamericano de Fisica y Quimica Ambiental; 2008
Institución organizadora:
UNSAM, UBA, SiFyQA
Resumen:
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It is a wide spectrum herbicide, non selective, widely in Argentina and worldwide, mainly in soybean, corn, sunflower and wheat crops.                  Zeolites are groups of porous aluminosilicates (mineral tectosilicates) found mainly in the nature in sedimentary rocks of volcanic origin. They possess cavities of molecular dimensions that allow them to work as ionic exchangers and as true molecular sieves. They have been used for the production of inclusion materials with diverse uses including different components inside their channels. They have also been used indeed in the treatment of contaminated waters for the removal of various kinds of pollutants. The zeolites can be specifically modified to increase their detoxification capacity (1, 2).                  In this work, batch adsorption experiments were carried out in 500 ppm PMG aqueous solutions with carbonized clinoptilolite (CMZ) (2), clinoptilolite-rich tuff hydrofobized with an organic ammonium base, octadecylammonium acetate (ODAZ) (1)  and with clinoptilolite without treatment (CZ) (Slovak origin). The experiments were carried out at constant ionic strength, temperature and pH.  Suspentions were .preparing at fixed pH and ionic strengths of KCl. After that, the herbicide solution was added and suspensions were kept with permanent agitation during 24 hours. The pH was readjusted to a constant value by adding aliquots of NaOH or HCl and was measured prior to all analyses The samples were centrifuged at 17000 rpm. The concentrations of remaining PMG were determined by ionic chromatography in the supernatant. Some complementary studies were carried out for characterization of the surfaces by means of SEM, UV-VIS diffuse reflectance, IEPpH and powder XRD.                  The PMG adsorption isotherms on CMZ, ODAS and CZ were determined. It was found that the best PMG adsorption rate appears for ODAZ