Sorção de ametryn em frações de solo associadas à matéria orgânica

• Autor(a) principal: Magalhães, Elisângela Jaqueline
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2184
• topic: Sorção; Isotermas de Freundlich; Solo; Ametryn; Sorption; Freundlich isotherms; Soil; Ametryn; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA

It was aimed at this work to evaluate the sorptive capacity of the herbicide ametryn in fractions of distrofic yellow red latosoil of the region of Viçosa, MG, mixed with different texts of organic matter. After the collection of the samples made in the superficial layer, horizon A, it was made the physical, chemical and mineralogic characterization of the soil and separation of the fractions into silt/sand and clay. After this, to these fractions of the soil it was mixed a vermicompost (organic matter in proportions 0, 5, 15 and 30 %). This mixture was incubated for 90 days in ambient temperature. The sorption ametryn in this material was evaluated on 0, 30, 60 and 90 days of incubation. To do the extration of ametryn of the fractions of soil + organic matter it was used the technique of Liquid-Liquid Extration with partition in low temperature (LLE-PLB), otimized and valided for parameters of linearity, seletivity, detection limit, quantification limit and precision. The extration of ametryn was carried through acetonitrile and etile acetat with recuperation media of 99 %. In the assays of sorption it was used the method batch equilibrium, lead in controlled conditions of laboratory. For this, 10,0 mL of solutions oin NaCl 0,100 mol L-1 contend 10,0; 30,0; 50,0; 80,0; 100,0; 120,0; 150,0 μg mL-1 of ametryn added in bottles of centrifugal contend 1 g of matrix emaining under horizontal agitation 27ºC until reaching the equilibrium time. After centrifugation the ametryn was extracted by technic LLE-PLB being quantification of ametryn made by gaseous chromatography with detector for ionization in flame. It was verified high sorption of ametryn in all soil fractions. The fraction silt/sand presented bigger sorptive capacity than soil and fraction clay. This effect was attributed to the high text of organic matter (19,31 %) found in this fraction. Difference in the sorption of ametryn with addition of organic matter was not observed. This fact can be explained high text of native organic matter and present clay in the ground. However, in the fractions silte/sand and clay when it was added organic substance verified positive effect in the increase of the sorption. The reduction of the sorption of ametryn with the incubation time can be attributed to the fast decomposition of the one which had organic substance at the favorable conditions. Reduction of the affinity of the sorption of ametryn in the soil and its mixed fractions was observed after the organic matter incubation of the matrix in humidity conditions next to the saturation.