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Mostrando ítems 11-20 de 126
Caracterização estrutural das substâncias húmicas aquáticas extraídas dos rios itapanhaú e ribeira de iguape
(Sociedade Brasileira de Química, 2011-01-01)
The knowledge of the structure characteristic of the Organic Matter is important for the understanding of the natural process. In this context aquatic humic substances (principal fraction) were isolated from water sample ...
Lability of heavy metal species in aquatic humic substances characterized by ion exchange with cellulose phosphate
(Elsevier B.V., 1997-01-01)
Labile metal species in aquatic humic substances (HSs) were characterized by ion exchange on cellulose phosphate (CellPhos) by applying an optimized batch procedure. The HSs investigated were pre-extracted from humic-rich ...
Reduction capability of soil humic substances from the Rio Negro basin, Brazil, towards Hg(II) studied by a multimethod approach and principal component analysis (PCA)
(Elsevier B.V., 2007-03-15)
This paper characterizes humic substances (HS) extracted from soil samples collected in the Rio Negro basin in the state of Amazonas, Brazil, particularly investigating their reduction capabilities towards Hg(II) in order ...
Thermal Decomposition Kinetics of Humic Substances Extracted from Mid-Rio Negro (Amazon Basin) Soil Samples
(Soc Brasileira Quimica, 2009-01-01)
In this work humic substances (HS) extracted from non-flooded (Araca) and flooded (Iara) soils were characterized through the calculation of stability and activation energies associated with the dehydration and thermal ...
Solar Radiation Effect on the Complexation Capacity of Aquatic Humic Substances with Metals
(Soc Brasileira Quimica, 2012-10-01)
This study had as main objective to assess the effect of solar radiation on the capacity of the aquatic humic substances (AHS) to complex Al3+, Cr3+, CrO42- and Ni2+. Microcosms were prepared with AHS from Preto River ...
Relative lability of trace metals complexed in aquatic humic substances using ion-exchanger cellulose-hyphan
(1997-12-01)
The purpose of this paper is to characterize the lability/inertness metal fractions complexed by aquatic humic substances (HS) in relation to pH, complexation time, and HS concentration. HS were preconcentrated by ...
Interaction of mercury(II) with humic substances from the Rio Negro (Amazonas State, Brazil) by means of an ion exchange procedure
(1998-12-01)
The aquatic humic substances (HS) investigated in this study with respect to their binding capability towards mercury(II) were isolated from the river Rio Negro, Amazonas State - Brazil, by means of the adsorbent XAD 8. ...
Characterization of the Interactions between Endocrine Disruptors and Aquatic Humic Substances from Tropical Rivers
(Soc Brasileira Quimica, 2011-01-01)
Interactions between two endocrine disruptors (ED) and aquatic humic substances (AHS) from tropical rivers were studied using an ultrafiltration system equipped with a 1 kDa cut-off cellulose membrane to separate free ED ...
Approach combining on-line metal exchange and tangential-flow ultrafiltration for in-situ characterization of metal species in humic hydrocolloids
(Springer Heidelberg, 2010-05-01)
This paper deals with the development and optimization of an analytical procedure using ultrafiltration and a flow-injection system, and its application in in-situ experiments to characterize the lability and availability ...
Interactions of chlorine with tropical aquatic fulvic acids and formation of intermediates observed by fluorescence spectroscopy
(2004-08-30)
The interactions of tropical aquatic fulvic acids (AFA) with chlorine and formation of trihalomethanes were characterized by fluorescence spectroscopy. The aquatic humic substances (AHS) were isolated from a dark-brown ...