Results 171 to 180 of about 2,736,925 (213)

Chemical Characteristics of Fulvic Acids

Journal AWWA, 1963
In the first article of this series on the nature of organic compounds that cause color in natural waters (BLACK, A. P. & CHRISTMAN, R. F. Characteristics of Colored Surface Waters. Jour. AWWA, 55 :753 [Jun. 1963]), data was presented concerning the physical and chemical properties of colored raw waters. This article discusses experimental evidence
A. P. Black, Russell F. Christman
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Pyrolysis of humic and fulvic acids

Geochimica et Cosmochimica Acta, 1969
Abstract Pyrolysis of humic and fulvic acids isolated from a North Carolina soil yields a variety of aromatic, heterocyclic and straight chain organ compounds. The pyrolysis products identified by gas chromatography and mass spectrometry indicate that humic and fulvic acids have aromatic and polysaccharide structures in their molecules.
R.L. Wershaw, G.E. Bohner
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Europium binding by fulvic acids

Analytica Chimica Acta, 1998
The binding of Eu to fulvic acid (FA) as a function of pH was determined by Schubert's method and by equilibrium dialysis. Data obtained by both methods showed a strong pH dependence, which was reproduced well by the model used to interpret the data (humic ion-binding model VI).
Lead, J. R., Hamilton-Taylor, John, Peters, A., Reiner, S., Tipping, E.   +4 more
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Protonation reactions of fulvic acids

Journal of Soil Science, 1988
SUMMARY The protonation reactions of fulvic acids are described in terms of a model involving a mixture of n monoprotic acids HA, HB, HC … pH titration data were analysed by nonlinear least squares methods, using a model having n ...
J. E. GREGOR, H. K. J. POWELL
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Effects of pH and fulvic acids concentration on the stability of fulvic acids – cerium (IV) oxide nanoparticle complexes

Chemosphere, 2016
The behavior of cerium (IV) oxide nanoparticles has been first investigated at different pH conditions. The point of zero charge was determined as well as the stability domains using dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy.
Oriekhova, Olena, Stoll, Serge
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Acid-base properties of aquatic fulvic acid

Analytica Chimica Acta, 1985
Abstract The acid-base properties of aquatic fulvic acid, concentrated from the Gota River, were studied by means of potentiometri titrations. The forward and reverse titrations exhibited hysteresis, which decreased as the fulvic acid underwent repeated titration.
N. Paxéus, M. Wedborg
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Determination of fulvic acids in water

Journal of Applied Chemistry, 1959
AbstractA method for the determination of fulvic acids present in naturally‐occurring waters has been developed, based on the measurement of the ultra‐violet absorption spectrum of the sample. The method has been applied to samples of water from different parts of the country, and the results indicate that for moorland waters the fulvic acids are very ...
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Acid pyrophosphate extraction of soil fulvic acids

Journal of Soil Science, 1986
SUMMARY A simple three step method is described for isolation of soil fulvic acids in high yield. The complexing agent H 2 P 2 O 7 2− (at pH 2) is used to release soil‐bound ...
J. E. GREGOR, H. K. J. POWELL
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Effect of fulvic acid on the photochemical degradation of methylparathion

Journal of Environmental Science and Health, Part B, 2010
Photochemical degradation of methylparathion (O,O,-dimethyl O-4 nitrophenylphosphorothioate) in the presence of fulvic acid (FA) between pH 2 and 7 was studied by differential pulse polarography (DPP). Fulvic acid and its photoproducts were not electro-active under the experimental conditions used in this study, and only the pesticide exhibited ...
José A, Manzanilla-Cano, Manuel H, Barceló-Quintal, Ligia Del C, Alcocer-Can, Tania I, Coral-Martínez   +3 more
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Sequestration of biogenic amines by alginic and fulvic acids

Biophysical Chemistry, 2006
The interaction of natural (alginic and fulvic acids) and synthetic (polyacrylic acid 2.0 kDa) polyelectrolytes with some protonated polyamines [diamines: ethylendiamine, 1,4-diaminobutane (or putrescine), 1,5-diaminopentane (or cadaverine); triamines: N-(3-aminopropyl)-1,4-diaminobutane (or spermidine), diethylenetriamine; tetramine: N,N'-bis(3 ...
DE STEFANO, Concetta, GIANGUZZA A, PIAZZESE D, PORCINO, NUNZIATINA, SAMMARTANO, Silvio   +4 more
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