CETMIC   05378
CENTRO DE TECNOLOGIA DE RECURSOS MINERALES Y CERAMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Caracterización y evaluacion de organoarcillas para la desorcion controlada de clorpirifos.
Autor/es:
M. PANTANETTI; M. DOS SANTOS AFONSO; R.M. TORRES SANCHEZ
Lugar:
Cacún
Reunión:
Congreso; VI Cong. Iberoamericano de Fisica y Quim.; 2011
Institución organizadora:
Soc. Iberoamericana de fisico y Quimica
Resumen:
The importance of understanding the interactions of agrochemicals in the soil, particularly with the
insecticide Chlorpyrifos (CPF), is motivated by its wide application in crops, besides the global need to
increase food production. Montmorillonite clays show significant adsorption capacity in the interlayer
spacing, which may be modified by treatment with salts of quaternary amines to produce organoclays. The
aim of this work was to obtain and characterize two organoclays (with octa decyltrimethylammonium
(CO) bromide and phenyl trimethylammonium (CF) chloride) and the raw clay (C) and to evaluate the
CPF desorption in order to further application such as slow-release formulations. Both organoclays
showed a decrease of specific surface and apparent diameter, respect to C, indicating a formation
increase of aggregates. While, only CO sample showed inversion to positive of the surface charge, the
XRD spectra of the reflexion peak (001) indicated interlayer entrance of both quaternary amines and
similar changes in the morphology were found for both organoclays. Samples with CPF adsorbed showed
an interlayer increase of 3Å for C sample while little or none increase was found for both organoclays,
indicating little CPF entrance in the interlayer surface. The zeta potential curves of samples with CPF
indicated an increase and a decrease of negative charge for both organoclays and C samples respect to
same samples without CPF. Both organoclays showed an first step (up to 25-50 h) of increasing
desorption, attaining at 100-150 h only 0, 1,34 y 2,1 % for CO, C and CF, respectively.