Fractionation Of Humic Substances
Mostrando 1-10 de 10 artigos, teses e dissertações.
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1. Fractionation of aquatic humic substances and dynamic of chromium species in an aquatic body influenced by sugarcane cultivation
Este estudo teve como objetivo principal avaliar a influência das SHA obtidas a partir de uma área de cultivo de cana de açúcar sobre a influência das espécies de crômio (Cr(III) e Cr(VI)). Foi estudada a capacidade de complexação (CC) das SHA com as espécies de crômio e estas foram caracterizadas por espectrofotometria de UV/Vis, fluorescência m
J. Braz. Chem. Soc.. Publicado em: 2014-01
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2. Frações da matéria orgânica e propriedades redox de substâncias húmicas em sedimentos de oceanos profundos
Previous studies have verified that free radicals such as quinone moieties in organic matter participate in the redox reactions in natural systems. These functional groups were positively correlated with the increase in aromaticity and hydrophobicity of the humic substances. As an alternative to relatively complex and expensive spectroscopic methods, the red
Quím. Nova. Publicado em: 2013
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3. MatÃria orgÃnica proveniente de Ãgua residuÃria de suinocultura na interaÃÃo e transporte de alaclor no solo
A aplicaÃÃo de Ãgua residuÃria de suinocultura ao solo como reÃso de Ãgua na agricultura resulta na adiÃÃo de matÃria orgÃnica total e dissolvida, que interferem na dinÃmica dos pesticidas no solo. Objetivou-se avaliar o efeito da aplicaÃÃo de matÃria orgÃnica total e dissolvida proveniente de dois sistemas de tratamento de Ãgua residuÃria d
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/08/2011
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4. Extraction kinetics and molecular size fractionation of humic substances from two brazilian soils
No presente trabalho foi estudada sistematicamente a extração de substâncias húmicas (SH) de um Oxisol e de um Mollisol do Sul do Brazil, empregando-se soluções de NaOH 0.1 e 0.5 mol L-1 e de Na4P2O7 0.15 mol L-1 a pH 7. A cinética e o rendimento de extração foram monitorados através de espectroscopia UV/Vis. Os ácidos húmicos (AH) e os ácidos f
Publicado em: 2010
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5. Fracionamento de Ba, Cr, Cu, Ni e Zn em solos tratados com lodo de esgoto em experimentos de longa duração
As the agronomic importance of the provision of agricultural sewage sludge, and its growing concerning environmental point of view, in this work decomposition procedures of soil samples subjected to the addition of sewage sludge were evaluated for total content determination of Ba, Cd, Cr, Cu, Ni, Pb and Zn; the contents of the aforementioned elements presen
Publicado em: 2010
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6. Estoque e qualidade da matéria orgânica do solo em áreas cultivadas com café sob sistemas agroflorestal e a pleno sol / Soil organic matter stock and quality in agroforestry and full sun coffee systems
Soil organic matter (SOM) restoring is considered a main goal in the enhancement of soil quality. The evaluation of changes in the SOM as a result of soil management practices is fundamental to identify strategies to increase agricultural production, avoiding soil degradation and decreasing the emission of greenhouse gases. In Brazil, no-tillage has been bro
Publicado em: 2009
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7. HUMIC SUBSTANCES IN SOILS FROM DIFFERENTS GEOMORPHOLOGIC FEATURE IN THE EDGE OF RIO GRANDE DO SUL PLATEAU / SUBSTÂNCIAS HÚMICAS EM SOLOS DE DIFERENTES FEIÇÕES GEOMORFOLÓGICAS NO REBORDO DO PLANALTO DO RIO GRANDE DO SUL
In spite of the great importance of the soil organic matter for the sustainability of the natural systems and of agricultural production, its study remains incipient in the area of the Edge of the Rio Grande do Sul Plateau, where different research have been reporting negative aspects of the inadequate soil use. In that sense, the carbon distribution evaluat
Publicado em: 2008
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8. Caracterização química de resíduos da produção de biodiesel compostados com adição mineral / Chemical characterization of residues from biodiesel production composted with mineral addiction
The production of biodiesel has in agriculture its base of sustentation. The culture of sugar cane and oleaginous species as castor oil plant after processing to obtain alcohol and vegetal oil, respectively, generates organic residues. These residues when used in agriculture in the compost form make possible the reduction of production costs and increase of
Publicado em: 2006
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9. Substâncias húmicas aquáticas: fracionamento molecular e caracterização de rearranjos internos após complexação com íons metálicos
The aquatic humic substances (AHS) investigated in this study were conventionally isolated from Rio Negro waters - Amazonas State/Brazil by means of the collector XAD 8. A special five-stage tangential-flow ultrafiltration device was used for analytical fractionation of AHS. The fractionation patterns (6 fractions each) showed that metal traces remaining in
Química Nova. Publicado em: 2001-06
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10. Substâncias húmicas: sistema de fracionamento sequencial por ultrafiltração com base no tamanho molecular
A sequential system for fractionation by ultrafiltration (SSFU) equipped with advanced membranes filters (molecular size cut-off: 5, 10, 30, 50 and 100 kDalton) of the polyethersulfone type was developed for analytical fractionation of humic substances (HS) extracted from aquatic systems or soils. The device consists of five membrane filters (Sartocon® Micr
Química Nova. Publicado em: 2000-06