scholarly journals Isolation of humic acid from oxidized lignite and complexation with metal cations

2017 ◽  
Vol 71 (4) ◽  
pp. 319-327
Author(s):  
Benjamin Catovic ◽  
Minela Sisic ◽  
Majda Srabovic ◽  
Melita Huremovic
Keyword(s):  
Humic Acid ◽  
Metal Ions ◽  
Humic Acids ◽  
Metal Binding ◽  
Base Material ◽  
Metal Cations ◽  
Biological Properties ◽  
Metal Nitrate ◽  
Chemical Difference ◽  
The Difference

Lignite is brown coal, which in its composition contains humic acids. Humic acids are produced by coal combustion, which leads to the enrichment of coal humic acids. Lignite, from the opet pit mine Sikulje, lignite ore ?Kreka?, Bosnia and Herzegovina, was fragmented and sieved to the appropriate size and used as a base material. The isolation of humic acid was carried out from pre-oxidized and dried lignite after which it was refined. Identification thus obtained humic acids was carried out by FTIR spectroscopy and its characterization of UV analysis which is determined by optical density of isolated humic acid and its complexation with metal cations. Data obtained by FTIR spectroscopic analysis of isolated humic acids show no significant structural and chemical difference in relation to the spectrum obtained for standard humic acids (Sigma Aldrich). UV analysis showed that isolated and standard humic acid have E4/E6 ratio in an appropriate range of 3?5, which indicates the presence of a large number of aliphatic structure. Based on the degree of humification was found that the isolated humic acids belong to the type B standard while humic acids belong to type A. The most important property of the humic substances is the ability to interact with the metal ions forming soluble or insoluble complexes which possess different chemical and biological properties and stability. The nature of the complex between humic acid and metal cation derived from the heterogeneous, polyelectric and polydispersive character humic acids that occurs due to the presence of a large number of functional groups. Complexation of humic acid is carried out with different concentrations of metal nitrate solutions and at different pH values. Different amounts of humic acids were used for the complexation. The amount of the free metal ions was measured with the ICP-OES methode. The data were also statistically analyzed with ANOVA. The results showed that increasing the pH reduces the concentration of metal ions adsorbed on humic acid and by increasing the concentrations and amounts of metal humic acid that power increases. On the basis of the difference in absorbance between metals and humic acids can be said that there is an interaction between the metal and the ligand and is based on absorbance values obtained can be determine the next set of metal binding to humic acids Pb>Zn>Ni>Cu.

EFFECT OF IRRIGATION AND GRASSING TO CHANGE SOME OF THE BIOLOGICAL PROPERTIES OF THE MINING OF BROWN CALCAREOUS SOILS

2019 ◽  
Vol 1 (1) ◽  
pp. 29-32
Author(s):  
Ruzimurod B. Boimurodov ◽  
Zebinisso Q. Bobokhonova
Keyword(s):  
Folic Acid ◽  
Humic Acid ◽  
Humic Acids ◽  
Rapid Growth ◽  
Growth And Development ◽  
Sharp Increase ◽  
Humus Content ◽  
Calcareous Soils ◽  
Biological Properties ◽  
Humus Accumulation

In this article is showing, that the irrigation mountain brown carbonate soils prone methods of irrigation and grassing comes the rapid growth and development of natural vegetation, which leads to intensive humus accumulation. Humus content in the upper layer is increased by 0.98% and a significantly smaller severely eroded. Increasing the amount of humus promotes accumulation mainly humic acids, that conducts to expansion of relations the content of humic acid: The content of folic acid. When grassing of soil traced sharp increase in the number associated with the related and R2 O3 humic acid.

Metal ion complexation by soft nanoparticles: the effect of Ca2+ on electrostatic and chemical contributions to the Eigen-type reaction rate

2015 ◽  
Vol 12 (2) ◽  
pp. 130 ◽  
Author(s):  
Raewyn M. Town
Keyword(s):  
Humic Acid ◽  
Trace Metal ◽  
Metal Ions ◽  
Electrostatic Field ◽  
Metal Binding ◽  
Metal Ion ◽  
Bulk Solution ◽  
Trace Metal Ions ◽  
Charged Nanoparticles ◽  
Soft Nanoparticles

Environmental context The speciation of trace metals in the environment is often dominated by complexation with natural organic matter such as humic acid. Humic acid is a negatively charged soft nanoparticle and its electrostatic properties play an important role in its reactivity with metal ions. The presence of major cations, such as Ca2+, can decrease the effective negative charge in the humic acid particle body and thus modify the chemodynamics of its interactions with trace metal ions. Abstract The effect of Ca2+ on the chemodynamics of PbII complexation by humic acid (HA) is interpreted in terms of theory for permeable charged nanoparticles. The effect of the electrostatic field of a negatively charged nanoparticle on its rate of association with metal cations is governed by the interplay of (i) conductive enhancement of the diffusion of cations from the medium to the particle and (ii) ionic Boltzmann equilibration with the bulk solution leading to accumulation of cations in the particle body. Calcium ions accumulate electrostatically within the HA body and thus lower the magnitude of the negative potential in the particle. For the case where trace metal complexation takes place in a medium in which the particulate electrostatic field is set by pre-equilibration in the electrolyte, the lability of Pb-HA complexes is found to be significantly increased in Ca2+-containing electrolyte, consistent with the predicted change in particle potential. Furthermore, the rate-limiting step changes from diffusive supply to the particle body in a 1–1 electrolyte, to inner-sphere complexation in a 2–1 electrolyte. The results provide insights into the electrostatic and covalent contributions to the thermodynamics and kinetics of trace metal binding by soft nanoparticles.

A study on the metal binding of humic acid by multitracer technique

2006 ◽  
Vol 94 (1) ◽  
Author(s):  
Zheng Chang ◽  
Shizuko Ambe ◽  
Kazuya Takahashi ◽  
Fumitoshi Ambe
Keyword(s):  
Humic Acid ◽  
Metal Ions ◽  
Small Molecule ◽  
Metal Binding ◽  
Technical Problems ◽  
Slow Diffusion ◽  
Dialysis Membranes

SummaryA method combining radioactive ‘multitracer’ and dialysis techniques was developed to study the binding of multiple metal ions to humic acid (HA). Technical problems such as the leakage of small-molecule HA segment and the slow diffusion of metal ions through the dialysis membranes were examined. Under the condition of pH = 4.0,

Selective enrichment of metal-binding proteins based on magnetic core/shell microspheres functionalized with metal cations

The Analyst ◽  
2015 ◽  
Vol 140 (12) ◽  
pp. 4197-4205 ◽  
Author(s):  
Caiyun Fang ◽  
Lei Zhang ◽  
Xiaoqin Zhang ◽  
Haojie Lu
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Binding Proteins ◽  
Metal Cations ◽  
Magnetic Core ◽  
New Method ◽  
Magnetic Microspheres ◽  
Core Shell ◽  
Selective Enrichment

A new method based on magnetic microspheres with metal ions was developed and applied to characterize putative metal binding proteins.

scholarly journals Intraparticulate speciation analysis of soft nanoparticulate metal complexes. The impact of electric condensation on the binding of Cd2+/Pb2+/Cu2+by humic acids

2016 ◽  
Vol 18 (15) ◽  
pp. 10049-10058 ◽  
Author(s):  
Raewyn M. Town ◽  
Herman P. van Leeuwen
Keyword(s):  
Humic Acid ◽  
Metal Ions ◽  
Metal Complexes ◽  
Humic Acids ◽  
Speciation Analysis ◽  
The Impact

The drastic role of electrostatics in the binding of metal ions by soft charged nanoparticulate humic acid complexants is demonstrated.

Peptides and their Metal Complexes in Neurodegenerative Diseases: from Structural Studies to Nanomedicine Prospects

2018 ◽  
Vol 25 (6) ◽  
pp. 715-747 ◽  
Author(s):  
Giuseppe Trapani ◽  
Cristina Satriano ◽  
Diego La Mendola
Keyword(s):  
Neurodegenerative Diseases ◽  
Metal Ions ◽  
Metal Binding ◽  
Crucial Role ◽  
Neuronal Development ◽  
Protein Complexes ◽  
Specific Binding ◽  
Biological Properties ◽  
Recent Developments

Background: The metal ions dyshomeostasis is increasingly recognized to play a crucial role in the development of aging-related neurodegenerative diseases. Metal trafficking in the brain is related to proteins regulating both uptake and efflux of metals in neurons. Different pathways may occur, depending on specific binding features of metallo-protein complexes. In particular, copper, zinc and iron are recognized to influence the biochemistry of proteins involved in neurodegeneration (for instance Aβ and α-synuclein), as well as those playing a crucial role in neuronal development and efficiency (neurotrophins). Nowadays the application of peptide-based drugs is widespread for different pathologies, but the short lifetime in vivo due to proteolysis and other shortcomings still limit their use. Methods: A structured search was performed about the state of the art on: i) peptidomimetic approaches used to obtain peptides mimicking the metal binding activities of proteins involved in neurons survival, ii) peptide-based nanostructures, as promising biomaterials in tissue engineering and substrates for neurites outgrowth and synapses formation. Results: Recent developments on metal-binding peptides and peptide nanostructures for therapeutic application in neurodegenerative diseases are reviewed, showing as metal ions interaction may affect structural and biological properties of different proteins involved in neurodegenerative diseases. Conclusion: This review provides a survey on peptides able to mimic some biofunctional activities of the whole protein, e.g., the binding features to metal ions, thus highlighting their promising potentialities as new, more effective, therapeutics. The integration of such peptides into multifunctional nanoplatforms can be a smart route for the development of biomaterials scaffolds and nanomedicine applications.

scholarly journals Destabilization and aggregation of aqueous humic acids solution by metal ions

2004 ◽  
Vol 3 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Tatjana Andjelkovic ◽  
Jelica Perovic ◽  
Milovan Purenovic ◽  
Darko Andjelkovic
Keyword(s):  
Humic Acid ◽  
Metal Ions ◽  
Humic Acids ◽  
Ionic Radius ◽  
Negative Charge ◽  
Positive Ions ◽  
Soil Humic Acid

The aggregation of soil humic acid (HA) after addition of cations was investigated by nephelometric measurements of HA solution turbidity. Here we show that aggregation is promoted by the presence of positive ions in the solution and that the order of increasing effectiveness in turbidity follows Schulze-Hardy rule. Also, the obtained results indicate that the cation with the largest ionic radius within a common valence is the most effective coagulant. Influence of unions follows the sequence: chloride < nitrate < sulphate, but it is insignificant comparing the influence of cation. This confirms that HA molecules are of negative charge.

The effect of temperature on tight metal binding by peat and soil derived solid humic acids

2001 ◽  
Vol 81 (3) ◽  
pp. 331-336 ◽  
Author(s):  
Elham A Ghabbour ◽  
Geoffrey Davies ◽  
Nadeem K Ghali ◽  
Matthew D Mulligan
Keyword(s):  
Humic Acids ◽  
Conformational Changes ◽  
Metal Binding ◽  
Equilibrium Constants ◽  
Tight Binding ◽  
Metal Cations ◽  
Effect Of Temperature ◽  
Binding Isotherms ◽  
Different Temperatures ◽  
Binding Enthalpy

The brown biomaterials called humic acids (HA) in peats and soils retain water and bind metal cations and other solutes. Studies of the interactions of purified solid peat and soil-derived HA from different countries with metal cations in water probe HA microstructures and help to characterize the metal binding sites. Labile cations such as Caaq2+, Co aq2+, Cu aq2+, Fe aq3+, Mg aq2+ and Mn aq2+ tightly bind to solid HAs in sequential steps. The isotherms A vs. c are well fitted with the Langmuir model and plots of 1/A vs. 1/c are linear for each step. Here, A is mmol bound metal g–1 HA and c is the equilibrium cation concentration (M). This paper compares the stoichiometric site capacities vi and equilibrium constants Ki for tight binding of Ca aq2+, Co aq2+, Cu aq2+, Fe aq3+, Mg aq2+ and Mn aq2+ at different solid HA sites. Measurements at different temperatures give linearly correlated metal binding enthalpy and entropy changes, indicating that conformational changes and cation/HA hydration/dehydration are important factors in metal binding and release by solid HAs. Key words: Humic acids; metal binding; isotherms; thermodynamics

Changes in the Humic Acid–Metal Complexation Characteristics Depending on Humification Degree / Humīnskābju – Metālu Kompleksveidošanās Rakstura Izmaiņas Atkarībā No Humifikācijas Pakāpes

2012 ◽  
Vol 51 (3) ◽  
pp. 228-237
Author(s):  
D. Dudare ◽  
M. Klavins
Keyword(s):  
Humic Acid ◽  
Stability Constants ◽  
Humic Acids ◽  
Complex Stability ◽  
Peat Layer ◽  
Raised Bog ◽  
Complexing Capacity ◽  
Humification Degree ◽  
Complexation Process ◽  
Complex Stability Constants

The aim of this study is to determine the Cu(II) complexing capacity and stability constants of Cu(II) complexes of humic acids isolated from two well-characterized raised bog peat profiles in respect to the basic properties and humification characteristics of the studied peats and their humic acids. The complex stability constants significantly change within the studied bog profiles and are well correlated with the age and decomposition degree of the peat layer from which the humic acids have been isolated. Among factors that influence this complexation process, molecular mass and ability to form micellar structures (supramolecules) of humic substances are of key importance.

Kinetic Adsorption of Humic Acids Mixture Obtained from Microalgae on Exfoliated Graphite Nanoplatelets

2018 ◽  
Vol 69 (1) ◽  
pp. 191-195
Author(s):  
Elena Radu ◽  
Elena Emilia Oprescu ◽  
Cristina Emanuela Enascuta ◽  
Catalina Calin ◽  
Rusandica Stoica ◽  
...  
Keyword(s):  
Humic Acid ◽  
Humic Acids ◽  
Alkali Treatment ◽  
Exfoliated Graphite ◽  
Acid Mixture ◽  
Acidic Ph ◽  
Graphite Nanoplatelets ◽  
Mixture Concentration ◽  
Ft Ir ◽  
Exfoliated Graphite Nanoplatelets

The dehydration of polysaccharides fraction in the presence of acid catalysts, is a chemical process in which results as secondary product humic matter. In our work, the humic acid mixture was for the first time based on our knowledge extracted from defatted microalgae biomass rich in polysaccharides by standard alkali treatment, followed by precipitation at acidic pH. The dried humic acid mixture has been characterized using infrared spectroscopic measurements (FT-IR). Exfoliated graphite nanoplatelets (xGnP) were used as new adsorbents for this type of humic acids mixture, their adsorption being investigated. The effect of several parameters such as: contact time, concentration of humic acid mixture, concentration of xGnP, temperature and pH of the solutions were studied. The process of adsorption took place with good results, in the following conditions: at a concentration of humic acid mixture of 18.6 mg L-1, an xGnP amount of 0.01 mg in 25 mL of solution, at a temperature of 25 �� and at acidic pH values, in aqueous solution.

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