scholarly journals Obtaining humic materials by mechanochemical reduction

2021 ◽  
Vol 340 ◽  
pp. 01001
Author(s):  
Natalya Yudina ◽  
Elizaveta Linkevich ◽  
Anna Saveleva ◽  
Oleg Lomovsky
Keyword(s):  
Mechanical Activation ◽  
Functional Groups ◽  
Fulvic Acids ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Humic And Fulvic Acids ◽  
Humic Materials ◽  
Spectral Coefficients ◽  
Mechanochemical Modification

In the study, a mechanochemical modification of peat was carried out, leading to an increase in the number of functional groups and an increase in the solubility of humic complexes with metals. It was shown that the mechanical activation of peat in the presence of Zn significantly increased the yield of extractable fulvic acids. An analysis of the spectral coefficients showed that humic and fulvic acids extracted from peat were characterized by an increased content of alcohol hydroxyl groups, C–O carbohydrate moieties, and carboxyl groups.

Inhibition of iron precipitation by humic substances in field drains

1994 ◽  
Vol 123 (2) ◽  
pp. 247-252 ◽  
Author(s):  
D. Vaughan ◽  
B. G. Ord
Keyword(s):  
Humic Substances ◽  
Oxidation State ◽  
Ferrous Iron ◽  
Fulvic Acids ◽  
Iron Deposition ◽  
Humic And Fulvic Acids ◽  
Iron Precipitation ◽  
Humic Materials ◽  
Drainage Waters

SummaryFerrous iron is oxidized and precipitated as iron ochre in field drains. In drainage waters taken from an ochre-producing site near Aberdeen, Scotland in 1987, iron deposition was inhibited by the addition of humic and fulvic acids, which form complexes with Fe(II). The inhibition was dependent on the concentrations of soluble humic materials and the proportion of Fe complexed. Iron deposition in the presence of humic substances is discussed in relation to the amount of the cation which is complexed and its oxidation state.

scholarly journals Development of methods for the separation and characterization of natural organic matter in dam water

2014 ◽  
Author(s):  
◽  
Pinkie Sobantu
Keyword(s):  
Molecular Weight ◽  
Humic Acid ◽  
Fulvic Acid ◽  
Humic Substances ◽  
Water Samples ◽  
Fulvic Acids ◽  
Hydroxyl Groups ◽  
Humic And Fulvic Acids ◽  
Vaal Dam

This project arose out the need for a simple method to analyse NOM on a routine basis. Water samples were obtained from the Vaal dam, which is one of the dams used by a hydroelectric power station. Analysis was preceded by separation of NOM into the humic and non-humic portions. The humic portion was separated into two fractions by employing a non-ionic resin (DAX-8) to separate humic acid from fulvic acid. High performance size exclusion chromatography (HPSEC), equipped with an Ultraviolet( UV) detector and an Evaporative Light Scattering (ELS) detector connected in series, was used to obtain molecular weight distribution information and the concentration levels of the two acids. Mixed standards of polyethylene oxide/glycol were employed to calibrate the selected column. Suwanee River humic acid standard was used as a certified reference material. The molecular weight distributions (MWDs) of the isolated fractions of humic and fulvic acids were determined with ELSD detection as weight-average (Mw), number-average (Mn) and polydispersity (ρ) of individual NOM fractions. The Mw/Mn ratio was found to be less than 1.5 in all the fractions, indicating that they have a low and narrow size fraction. An increase in Mn and Mw values, with increasing wavelength for all three humic substances (HS) examined was observed. The HS, isolated from the dam water, was found to be about the same molecular weight as the International Humic Acid Standard (IIHSS). For the fulvic acid standard, the molecular weight was estimated to be around 7500 Da. Characterization of NOM was done to assist in the identification of the species present in the water. FTIR-ATR was used to as a characterization tool to identify the functional groups in the structure of the humic and fulvic acid respectively present in the Vaal Dam. Analysis of the infrared (IR) spectra indicated that the humic acids of the Vaal dam have phenolic hydroxyl groups, hydroxyl groups, conjugated double bond of aromatic family (C=C), and free carboxyl groups. The isolation method has proved to be applicable and reliable for dam water samples and showed to successfully separate the humic substances from water and further separate the humic substances into its hydrophobic acids, namely, humic and fulvic acids. It can be concluded that the Eskom Vaal dam composes of humic substance which shows that the technique alone gives a very good indication of the characteristics of water. The HPSEC method used, equipped with UV and ELSD was able to identify the molecular weight range of NOM present in source water as it confirmed that the Eskom Vaal dam contains humic substances as humic acid and fulvic acid and these pose a health concern as they can form disinfectant byproducts in the course of water treatment with chemicals. FTIR characterization was successful as important functional groups were clearly assigned. Lastly, the use of the TOC and DOC values to calculate SUVA was also a good tool to indicate the organic content in water. It is recommended to use larger amounts of water must be processed to obtain useful quantities of the humic and fulvic acid fractions.

scholarly journals New possibility for characterization of dissociation behaviour of supramolecular electrolytes: results obtained for the International Humic Substances Society standard and reference samples by coulometry

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Martina Klučáková
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Humic Substances ◽  
Functional Groups ◽  
Dissociation Constants ◽  
Fulvic Acids ◽  
Molecular Organization ◽  
Humic And Fulvic Acids ◽  
Acid Base ◽  
Reference Samples

Abstract Background Humic substances can be considered as polyelectrolytes with supramolecular character and complicated behaviour in water environment. The fractions of humic substances dissolved in water are the most active ones and determinative for their functioning in nature, where the proton-binding and dissociation ability play a crucial role. The dissociation behaviour of humic and fulvic acids can be affected by different circumstances including their concentration which is directly connected with the molecular organization of humic particles in solution and the accessibility of their ionizable functional groups. This study is focused just on these active fractions and their dissociation behaviour in the dependence on their content in studied system. Results Standards and reference samples of International Humic Substances Society were used. Flow-through coulometry was used to determine the total content of acidic functional groups in fulvic solutions and humic leachates. The amount of dissociated acidic groups was determined on the basis of potentiometry. Several differences between the behaviour of humic and fulvic acids were found. While whole samples of fulvic acids including the weakest functional groups were analysed, only the active dissolved humic fractions containing stronger acidic functional groups were characterized. The fractions containing higher amounts of the weakest functional groups remained insoluble. The dissociation degree of fulvic acids decreased with their increasing content, but a maximum on its concentration dependence obtained for humic acids was observed. Conclusions Two different values of dissociation constants were determined for each sample. The first was determined on the basis of the extrapolation of infinite dilution, second was determined as their average value in the region of high concentrations in which it was constant. Obtained values characterize the functioning of dissolved humic substances from point of view of their dissociation ability. The results obtained by this approach can help to predict the acid–base behaviour of dissolved organic carbon in soil and generally in nature. The acid–base behaviour of dissolved organic carbon depends on its ratio to water. It behaves differently in soil which is dry and in soil which is wet or saturated by water.

Radio-Labelled Humic Materials in Migration Studies

1992 ◽  
Vol 294 ◽  
Author(s):  
Lars Carlsen ◽  
Pia Lassen ◽  
Peter Warwick ◽  
Amanda Randall
Keyword(s):  
Environmental Fate ◽  
Fulvic Acids ◽  
Migration Studies ◽  
Humic And Fulvic Acids ◽  
Humic Material ◽  
Naturally Occurring ◽  
Significant Strength ◽  
Soils And Sediments ◽  
Humic Materials

ABSTRACTHumic- and fulvic acids are able to complex polyvalent metal ions, e.g. radionuclides, leading to soluble complexes of significant strength, thereby decreasing the sorption of these compounds to soils and sediments. The interaction of humic materials with radionuclides may significantly influence the availability and transport of the latter in the environment. Typically, studies along these lines have focussed almost exclusively on the radionuclides, whereas the actual role of the humic material has been elucidated only indirectly. In order directly to study the behaviour of the naturally occurring organic macro-molecules in relation to the environmental fate of radionuclides, radio-labelled humic- and fulvic acids can advantageously be applied. Radio-labels such as 14C and 125I have successfully been covalently incorporated in humic- and fulvic acids. Labelling of humic substances as well as preliminary migration studies are discussed

TERPENOIDS: V. SENEGENIN: FUNCTIONAL GROUPS AND PART STRUCTURE

1964 ◽  
Vol 42 (3) ◽  
pp. 491-501 ◽  
Author(s):  
J. J. Dugan ◽  
P. De Mayo ◽  
A. N. Starratt
Keyword(s):  
Functional Groups ◽  
Empirical Formula ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Carboxyl Group ◽  
Secondary Hydroxyl ◽  
Part Structure ◽  
Oxygen Atoms

Senegenin, the sapogenin from Polygalasenega has been shown to contain chlorine; it has the empirical formula C30OH45O6Cl. The oxygen atoms, contrary to earlier work, are contained in two carboxyl groups and two secondary hydroxyl groups. There is one isolated ethylenic linkage. The environment of the hydroxylic functions and one carboxyl group has been shown to be as in (XI).

SOME CHARACTERISTICS OF HUMIC MATERIALS IN CARIBBEAN VERTISOLS

1983 ◽  
Vol 63 (2) ◽  
pp. 151-159 ◽  
Author(s):  
M. B. HOLDER ◽  
S. M. GRIFFITH
Keyword(s):  
Functional Groups ◽  
Fulvic Acids ◽  
Comparative Investigation ◽  
High Reactivity ◽  
Spectrophotometric Analysis ◽  
Humic Materials ◽  
Dta Analysis ◽  
Metal Organic ◽  
The Caribbean ◽  
Organic Matter Fractions

A comparative investigation of the analytical features of organic matter fractions of acidic and calcium-saturated Vertisols (Ca-Vertisols) from the Caribbean was undertaken. The elemental composition and functional group content of the humic acids (HAs) and fulvic acids (FAs) were similar to previously reported values, except for the low yielding HAs of Ca-Vertisols which contained a greater proportion of O (35.82–47.17%). In addition, high values (8.38 meq/g–11.71 meq/g) for the COOH functional groups of the FAs emphasized the inherent high reactivity of the humic materials. Spectrophotometric analysis supported the view arrived at through chemical analysis that metal-organic (FA) complexes of Vertisols contained Al, Fe and Si with more soluble complexes in the Ca-Vertisols and in the presence of a basic cation (Ca). DTA analysis indicated that the organo-mineral complexes of Vertisols were regular and thermostable. Key words: Vertisols, humic materials, functional groups, infrared, DTA

Reduction of Arsenates by Humic Materials

2006 ◽  
Vol 3 (2) ◽  
pp. 131 ◽  
Author(s):  
Noel E. Palmer ◽  
John H. Freudenthal ◽  
Ray von Wandruszka
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Reduction Potential ◽  
Fulvic Acids ◽  
Redox Potentials ◽  
Humic And Fulvic Acids ◽  
Concentrated Solutions ◽  
Inductively Coupled ◽  
Humic Materials ◽  
Plasma Mass Spectrometry

Environmental Context.Reduction of arsenic(v) to arsenic(iii) in the environment is of interest because of the greater toxicity and mobility of the latter. It is important to know to what extent humic materials (which are ubiquitous in soils) can act as abiotic reducing agents, and what factors influence their actions. Abstract.Inorganic arsenates were found to be reduced to arsenite by homogeneous aqueous solutions of several humic and fulvic acids. Because of the concentration dependence of the redox potentials of humics, reduction was shown to be less likely in more concentrated solutions. This was especially true in higher pH ranges, and varied with the type of material used. Ion chromatography, validated by inductively coupled plasma mass spectrometry, was used to speciate arsenic after exposure to aqueous humates and fulvates. Reduction of As(v) proceeded in the 20–60% range, depending on the humic or fulvic acid used. The fraction of arsenate that was reduced initially increased with humic concentration, but leveled off as the reduction potential decreased at higher concentrations. Re-oxidation of As(iii) in humic solutions could be achieved by extended bubbling with air. Reduction capacities of two humates tested, as measured by I2 titration, were found to be significantly different.

Comparative Studies of Brown Coal and Lignin. II. The Action of Concentrated Alkali at Elevated Temperatures

1960 ◽  
Vol 13 (4) ◽  
pp. 567 ◽  
Author(s):  
BM Lynch ◽  
RA Durie
Keyword(s):  
Functional Groups ◽  
Brown Coal ◽  
Comparative Studies ◽  
Elevated Temperatures ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Brown Coals ◽  
Simple Chemical ◽  
Phenolic Hydroxyl Groups ◽  
Dihydric Phenol

A study was made of the products formed by treating brown coal or lignin with concentrated aqueous or ethanolic alkali at 200 �C. With brown coals a major redistribution of the oxygen-containing functional groups appeared to occur, because the products contained aliphatically linked carboxyl groups and aliphatic hydroxyl, as well as phenolic hydroxyl groups. The behaviour of lignin under the same conditions was less clear but sufficiently similar to that of brown coal to suggest that reactions of the same type were occurring in both cases. Reactions involving decarboxylation, ring scission of dihydric phenol structures, and subsequent hydrogenation are suggested tentatively as the main steps in the formation of the products. The results provide some additional evidence for the view that there is a simple chemical relation between Victorian brown coal and lignin.

ATRAZINE HYDROLYSIS IN SOILS: CATALYSIS BY THE ACIDIC FUNCTIONAL GROUPS OF FULVIC ACID

1985 ◽  
Vol 65 (3) ◽  
pp. 435-443 ◽  
Author(s):  
DONALD S. GAMBLE ◽  
SHAHAMAT U. KHAN
Keyword(s):  
Fulvic Acid ◽  
Functional Groups ◽  
Natural Waters ◽  
Acid Catalysis ◽  
Carboxyl Groups ◽  
Acid Solutions ◽  
Predictive Equation ◽  
Hydrogen Ions ◽  
Soil Solutions ◽  
Humic Materials

The catalysis of atrazine hydrolysis at 25.0 °C by the types of acidic functional groups found in humic materials has been investigated. No evidence of catalysis by carboxylate ions was observed. From a knowledge of the types and numbers of acid functional groups in a quantitatively characterized fulvic acid, and the distributions of their KA values it was found that hydrogen ions and undissociated carboxyl groups were the only catalytic agents. The carboxyl groups have a second-order kAH of 7.88 days −1∙M−1. Weakly acidic functional groups having [Formula: see text]showed no catalysis. A predictive equation has been produced for the half-life of atrazine in fulvic acid solutions at 25.0 °C. It represents a general class of equations which should permit the practical prediction of atrazine persistence in soil solutions and other natural waters. Key words: Atrazine hydrolysis, atrazine persistence, fulvic acid, fulvic acid carboxyls, acid catalysis, carboxyl catalysis

Evaluation of the Properties of Humus Liquid of Earthworm Eisenia Foetida Obtained from Different Rachis

2017 ◽  
Vol 3 (02) ◽  
Author(s):  
Ramiro Remigio Gaibor Fernández ◽  
Abraham Adalberto Bayas Zamora ◽  
Galo Israel Muñoz Sánchez ◽  
Cristhian Adrián Rivas Santacruz
Keyword(s):  
Plant Growth ◽  
Fulvic Acids ◽  
Cattle Manure ◽  
Eisenia Foetida ◽  
Humic And Fulvic Acids ◽  
Livestock Manure ◽  
A Value ◽  
The One ◽  
Liquid Slurry

The objective of the present investigation was to evaluate the physical characteristics of the vermicompost and the quality of the purine of the red Californian (Eisenia foetida) using different substrates of feed for these worms. For this purpose, nine treatments were studied: 75% African palm rachis + 25% cattle manure, 50% African palm rachis + 50% cattle manure, 25% African palm rachis + 75% livestock manure, 50% manure of cattle, 50% of manure of cattle, 25% of manure of cattle, 50% of manure of cattle, 50% of manure of cattle, 50% of rach of coconut + 50% of manure of Livestock, 25% coccus rachis + 75% livestock manure. The substrate made up of 50% of rachis of coconut and 50% of livestock manure can be used in nurseries or nurseries for being the one that registered a value of pH 7.3 plus the closest to the neutral compared to the others, besides this (75% of oil palm rachis and 25% of cattle manure) showed a higher content of humic and fulvic acids (0.87 and 0.45 p / p, respectively), compounds that are important for agriculture by stimulating plant growth, in addition to this reflection 0.06% sulfur content, 4.0 ppm boron, 7.0 ppm copper, 47.5 ppm iron, 6.0 ppm manganese, with a presence of microorganisms of the species Trichoderma, Penicillium, Cladosporium sp. in amounts of 1.91x105 UFC / ml, however in this substrate was obtained between 13.3 and 43.5% less liquid slurry in Comparison with other treatments.

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