AN EXAMINATION OF THE HUMIC ACIDS OF SPHAGNUM PEAT

1964 ◽  
Vol 44 (1) ◽  
pp. 76-87 ◽  
Author(s):  
D. G. Smith ◽  
J. W. Lorimer
Keyword(s):  
Molecular Weight ◽  
Humic Acid ◽  
Sodium Hydroxide ◽  
Humic Acids ◽  
Infrared Spectra ◽  
Low Molecular Weight ◽  
Salt Solutions ◽  
Similar Composition ◽  
Sphagnum Peat ◽  
Dilute Sodium Hydroxide

Humic acid fractions were prepared by the repeated extraction of Sphagnum peat with dilute sodium hydroxide. The infrared spectra of the initial fractions were typical of humic acids. Spectra of the later fractions were indicative of an aromatic structure similar to that of lignin. The content of methoxyl groups, which had remained constant through the earlier fractions, increased rapidly in the later fractions. Changes in the intrinsic viscosity of the fractions in aqueous alkali and salt solutions paralleled those observed in the infrared spectra and methoxyl group content. The results show that humic acids of similar composition and increasing molecular weight were extracted initially, and that low molecular weight material resembling lignin predominated towards the end of the extraction. The presence of lignin was confirmed by alkaline nitrobenzene oxidation of a peat residue. Dilute sodium pyrophosphate extracted humic acids which were similar in all respects to the first fraction obtained by extraction with dilute sodium hydroxide.

scholarly journals An integrated chemical and micromorphological investigation of humic substances in three podzolized soils of the Netherlands.

1982 ◽  
Vol 30 (3) ◽  
pp. 205-226
Author(s):  
J. Drozd ◽  
A. Jongerius ◽  
S. Kowalinski
Keyword(s):  
Molecular Weight ◽  
Chemical Composition ◽  
The Netherlands ◽  
Humic Substances ◽  
Humic Acids ◽  
Infrared Spectra ◽  
Fulvic Acids ◽  
Low Molecular Weight ◽  
Ap Horizon ◽  
The Stability

The humic substances in a 'Holt' leptic podzol, a 'Haar' humic podzol and a 'Veld' gleyic podzol from the Netherlands were analysed chemically and micromorphologically. The absorption spectra of Na-humates in visible light and infrared spectra were determined for the humic acids. The translocation and distribution of the principal humus compounds occurred by mechanical illuviation in the 'Holt' podzol, and by translocation in solution in the 'Haar' podzol and the 'Veld' podzol. The micromorphological images were closely correlated with the chemical composition of the humic substances. Illuviation cutans occurring in the B horizons of the 'Haar' podzol and the 'Veld' podzol appeared to consist mainly of fulvic acids. The dark humus micro-aggregates characteristic of the 'Haar' podzol and the Ap horizon of the 'Veld' podzol were composed mainly of bitumens, humins and humic acids of high molecular weight, while the brown micro-aggregates of the 'Holt' podzol and the lower horizons of the 'Veld' podzol consisted mainly of fulvic acids and humic acids of low molecular weight. The stability of micro-aggregates was correlated with their composition. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Reduction of Surfactant Retention in Limestones Using Sodium Hydroxide

SPE Journal ◽  
2018 ◽  
Vol 24 (01) ◽  
pp. 92-115 ◽  
Author(s):  
D.. Wang ◽  
M.. Maubert ◽  
G. A. Pope ◽  
P. J. Liyanage ◽  
S. H. Jang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Sodium Hydroxide ◽  
Anionic Surfactants ◽  
Geochemical Modeling ◽  
Low Molecular Weight ◽  
Low Concentrations ◽  
Reservoir Conditions ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Indiana Limestone

Summary Geochemical modeling was used to design and conduct a series of alkaline/surfactant/polymer (ASP) coreflood experiments to measure the surfactant retention in limestone cores using sodium hydroxide (NaOH) as the alkali. Surfactant/polymer (SP) coreflood experiments were conducted under the same conditions for comparison. NaOH has been used for ASP floods of sandstones, but these are the first experiments to test it for ASP floods of limestones. Two studies performed under different reservoir conditions showed that NaOH significantly reduced the surfactant retention in Indiana Limestone. An ASP solution with 0.3 wt% NaOH has a pH of approximately 12.6 at 25°C. The high pH increases the negative surface charge of the carbonate, which favors lower adsorption of anionic surfactants. Another advantage of NaOH is that low concentrations of only approximately 0.3 wt% can be used because of its low molecular weight and its low consumption in limestones. Most reservoir carbonates contain gypsum or anhydrite, and therefore sodium carbonate (Na2CO3) will be consumed by the precipitation of calcium carbonate (CaCO3). As shown in the two studies, NaOH can be used in limestone reservoirs containing gypsum or anhydrite.

scholarly journals A dialysis accessory for attenuated total reflection infrared spectroscopy

2006 ◽  
Vol 20 (3) ◽  
pp. 89-94 ◽  
Author(s):  
Maria Krasteva ◽  
Saroj Kumar ◽  
Andreas Barth
Keyword(s):  
Molecular Weight ◽  
Infrared Spectroscopy ◽  
Infrared Spectra ◽  
Chemical Oxidation ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Low Molecular Weight ◽  
Dialysis Membrane ◽  
Effects Of Ph ◽  
Sample Compartment

A dialysis accessory for attenuated total reflection (ATR) infrared spectroscopy is described together with an evaluation based on known systems with well-studied infrared spectra, such as chemical oxidation and reduction of cytochromecand substrate binding to the Ca2+-ATPase. Changes in the infrared spectra of the two proteins are successfully monitored with the dialysis accessory. The accessory was developed in our laboratory for the diamond 9-reflections SensIR ATR unit. It can be used to study absorbance changes of macromolecules which are induced by low molecular weight compounds, for example the binding of substrates, inhibitors or ions to macromolecules as well as effects of pH, ionic strength or denaturants on the structure of macromolecules. The dialysis accessory confines the macromolecule of interest to a sample compartment created between the ATR crystal and the dialysis membrane. On the other side of the dialysis membrane, a reservoir for the sample medium is created. In this way the low molecular weight compound of interest can exchange freely between the reservoir and the sample compartment via the dialysis membrane. This provides a flexible way to change sample conditions for the macromolecule of interest, allowing for example initiation of ligand binding.

Low-molecular-weight fractions of Bulgarian lignite humic acids

Fuel ◽  
1981 ◽  
Vol 60 (8) ◽  
pp. 685-688 ◽  
Author(s):  
Elena M. Balabanova-Radonova ◽  
Maia D. Stefanova
Keyword(s):  
Molecular Weight ◽  
Humic Acids ◽  
Low Molecular Weight ◽  
Lignite Humic Acids ◽  
Molecular Weight Fractions

scholarly journals Visualization and Quantification of the Impact of Humic Acid on Zinc Accumulation in Aquatic Plants Using a Low-Molecular-Weight Fluorescent Probe

2021 ◽  
Vol 19 (2) ◽  
pp. 49-63
Author(s):  
Thenuwara Arachchige Omila Kasun Meetiyagoda ◽  
Kabul Fadilah ◽  
Masayori Hagimori ◽  
Mudalige Don Hiranya Jayasanka Senavirathna ◽  
Takeshi Fujino
Keyword(s):  
Molecular Weight ◽  
Humic Acid ◽  
Fluorescent Probe ◽  
Aquatic Plants ◽  
Low Molecular Weight ◽  
Zinc Accumulation ◽  
The Impact

scholarly journals Humic Acid Reduction by Propionibacterium freudenreichii and Other Fermenting Bacteria

1998 ◽  
Vol 64 (11) ◽  
pp. 4507-4512 ◽  
Author(s):  
Marcus Benz ◽  
Bernhard Schink ◽  
Andreas Brune
Keyword(s):  
Molecular Weight ◽  
Humic Acids ◽  
Iron Reduction ◽  
Ferric Iron ◽  
Hydrogen Oxidation ◽  
Low Molecular Weight ◽  
Propionibacterium Freudenreichii ◽  
Iron Reducing Bacteria ◽  
Fermenting Bacteria ◽  
Reducing Bacteria

ABSTRACT Iron-reducing bacteria have been reported to reduce humic acids and low-molecular-weight quinones with electrons from acetate or hydrogen oxidation. Due to the rapid chemical reaction of amorphous ferric iron with the reduced reaction products, humic acids and low-molecular-weight redox mediators may play an important role in biological iron reduction. Since many anaerobic bacteria that are not able to reduce amorphous ferric iron directly are known to transfer electrons to other external acceptors, such as ferricyanide, 2,6-anthraquinone disulfonate (AQDS), or molecular oxygen, we tested several physiologically different species of fermenting bacteria to determine their abilities to reduce humic acids.Propionibacterium freudenreichii, Lactococcus lactis, and Enterococcus cecorum all shifted their fermentation patterns towards more oxidized products when humic acids were present; P. freudenreichii even oxidized propionate to acetate under these conditions. When amorphous ferric iron was added to reoxidize the electron acceptor, humic acids were found to be equally effective when they were added in substoichiometric amounts. These findings indicate that in addition to iron-reducing bacteria, fermenting bacteria are also capable of channeling electrons from anaerobic oxidations via humic acids towards iron reduction. This information needs to be considered in future studies of electron flow in soils and sediments.

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