scholarly journals MODIFICATION OF HUMIC SUBSTANCES FOR DEVELOPMENT OF MATERIALS FOR ENVIRONMENTAL TECHNOLOGIES

2019 ◽  
Vol 1 ◽  
pp. 101
Author(s):  
Maris Klavins
Keyword(s):  
Molecular Weight ◽  
Metal Ions ◽  
Humic Substances ◽  
Functional Groups ◽  
Metal Ion ◽  
Spectral Characteristics ◽  
Water Soluble ◽  
13C Nuclear Magnetic Resonance ◽  
Mobility Behaviour ◽  
Derivatives Of

Humic substances are high molecular weight refractory polycationites formed during decay of living organic matter and through biosynthesis of low molecular weight organic substances (metabolites or decay products of living organisms). Presence of many functional groups in the structure of humic substances determines their ability to interact with metal ions forming stable complexes and influencing metal ion speciation in the environment and mobility, behaviour and speciation forms in the environment. Presently humic substances are a product of industrial scale and quantities in amounts of hundreds of tons are produced. The aim of this study is to analyse derivatization possibilities of humic substances. To achieve this aim derivatization of humic substances using acylation (at first introduction of acetylgroups, but also changing length acyl chains are considered) are used. Also alkylation is used. Mild oxidation can help to obtain modified products with reduced molecular weight. Another approach includes introduction of new functional groups and structures. To achieve this aim, conjugates with short peptides, amines and sugar derivatives using coupling with water-soluble carbodiimides are obtained. As basic characteristics elemental analysis as well as functional analysis have been used, supported with Fourier transform infrared (FTIR), 13C nuclear magnetic resonance spectrometry and other methods. Derivatives of humic substances containing sulpho, amino, and hydroxylgroups and thiolgroups were synthesized and their properties were analyzed in respect to their their elemental composition; functional group content changes in spectral characteristics. The derivatives of humic substances showed significant differences in the number and in ability to interact with the metal ions, which were reflected in their complexation properties towards metal ions. FTIR spectra gave evidence of the presence of metal ions, strongly bound and protected in inner sphere complexes. The obtained derivatives of humic substances can be used for remediation of environment contaminated with heavy metal ions.

scholarly journals Water soluble metal-polymeric complexes of gallium and triple co-polymer of N-vinylpyrrolidone with N-vinylformamide and N-vinylminodiacetic acid

2019 ◽  
Vol 485 (3) ◽  
pp. 306-310
Author(s):  
N. I. Gorshkov ◽  
A. Yu. Murko ◽  
I. I. Gavrilova ◽  
I. I. Malakhova ◽  
V. D. Krasikov ◽  
...  
Keyword(s):  
Molecular Weight ◽  
1H Nmr ◽  
Metal Ion ◽  
Water Soluble ◽  
Polymer Complex ◽  
Nmr Data ◽  
Exclusion Chromatography ◽  
Polymeric Complexes ◽  
Metal Polymer

A terpolymer with a molecular weight of 45 kDa containing 7 mol.% of vinylamine units, 80 mol.% of vinylpyrrolidone, and 3 mol.% of vinyliminodiacetic acid units has been synthesized. Its complexation with Ga3+ ion has been studied by HPLC. The resulting metal–polymer complex has been characterized by exclusion chromatography and spectral (IR, 1H NMR) data. The complex has a monomolecular structure where the metal ion acts as an anchor fragment between vinyliminodiacetic acid units and is stable in the reaction of interligand exchange with histidine.

Metal ion binding by humic substances as emergent functions of labile supramolecular assemblies

2020 ◽  
Vol 17 (3) ◽  
pp. 252 ◽  
Author(s):  
Elena A. Vialykh ◽  
Dennis R. Salahub ◽  
Gopal Achari
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Substances ◽  
Metal Binding ◽  
Metal Ion ◽  
Computational Modelling ◽  
Intermolecular Forces ◽  
Metal Complexation ◽  
Emergent Properties ◽  
Metal Availability

Environmental contextThe fundamental basis for the high flexibility of humic substances is still unclear, though it is crucial for the understanding of metal bioavailability and toxicity in soil and aqueous environments. We show at the molecular level how characteristics of organic matter affect metal binding depending on the environmental conditions. Such understanding will help in the modulation of metal availability in soil and water in changing environmental situations. AbstractIn this work, we explore the hypothesis that humic substances (HS) can be perceived as labile supramolecular assemblages, the functioning of which is mainly determined by chemical composition and characteristics, the size of molecular units and weak intermolecular forces, rather than the exact primary structure of molecular moieties and their spatial configuration. To test the hypothesis, 72 computational models of three different organic mixtures were composed. The formation of inner and outer sphere metal–ligand complexes, metal binding sites, complex configurations, binding energies and aggregation/dissolution as emergent properties of HS were determined under various conditions. The results of computational modelling revealed that: (i) the highest Cu2+ binding (55.6%) was by the SRFA-22 organic model, which represents low-molecular-weight fulvic acids. In contrast, the highest amount of inner-sphere Mg–organic matter complex (63.4%) was formed in SRHA-6, which has higher-molecular-weight constituents. Therefore, a correlation between the type of cation, the system aromaticity and the extent of metal complexation is proposed. (ii) Increase of metal ion concentration and decrease of water content resulted in an increase in the number of hydrogen bonds and more compact and stable aggregates with lower hydrophilic and higher hydrophobic surface areas in SRFA-22. However, in SRHA-6, the results varied owing to the competition between metal binding, H-bonding and non-polar interactions in the structural arrangement of the aggregates. In general, the aggregation process, driven by metal complexation and water removal, resulted in the formation of more stable conformers, with lower potential energy, with the only exception of SRHA-6–Cu.

scholarly journals Synthesis of Water-Soluble Copolymers of N-vinylpyrrolidone with N-vinyldithiocarbamate as Multidentate Polymeric Chelation Systems and Their Complexes with Indium and Gallium

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4681
Author(s):  
Nikolay I. Gorshkov ◽  
Andrey Yu. Murko ◽  
Irina I. Gavrilova ◽  
Marina A. Bezrukova ◽  
Albert I. Kipper ◽  
...  
Keyword(s):  
Metal Ions ◽  
Alkaline Medium ◽  
Carbon Disulfide ◽  
Water Soluble ◽  
Polymer Complexes ◽  
Chromatographic Methods ◽  
Gallium Metal ◽  
Molecular Masses ◽  
Derivatives Of ◽  
Metal Polymer

Dithiocarbamate (DTC) derivatives of N-vinylpyrrolidone-N-vinylamine (VP–VA) copolymers were synthesized via reaction between the copolymers and carbon disulfide in alkaline medium; molecular masses of the products were 12 and 29 kDa; the VP:VDTC ratios were 94:6 and 83:17 mol.%. Complexation between the obtained DTC derivatives and metal ions (indium and gallium) was investigated. It was demonstrated that metal–DTC ligand complexes with 1:3 ratio between components were formed. Gallium metal–polymer complexes (MPC) were unstable in solution. Individual indium MPC were isolated and characterized by spectral and chromatographic methods. Unlike similar gallium MPC, they appeared to be stable in histidine challenge reaction.

Metal Binding by Water-Soluble Polychelates and Implications for Agriculture

2011 ◽  
Vol 64 (12) ◽  
pp. 1593 ◽  
Author(s):  
Garry W. Warrender ◽  
Robert G. Gilbert
Keyword(s):  
Metal Ions ◽  
Atomic Absorption ◽  
Emulsion Polymerization ◽  
Atomic Absorption Spectroscopy ◽  
Metal Binding ◽  
Metal Ion ◽  
Agricultural Soils ◽  
Water Soluble ◽  
Aminosalicylic Acid ◽  
Chemical Binding

Means are developed to improve the metal ion delivery/remediation potential of polyacrylamides (PAMs), by incorporation of the co-monomer N-acryloyl-4-aminosalicylic acid. The polymers were synthesized by solution and inverse emulsion polymerization. The chemical binding of two soil micronutrients, Cu2+ and Fe3+, were investigated using atomic absorption spectroscopy. The modified PAM had an enhanced affinity for metal ions compared with conventional PAMs. This modified PAM has the potential as a delivery tool of plant micronutrients and stabilizers for agricultural soils undergoing intense irrigation. The same polymers may also provide a detoxifying effect in these applications where some micronutrient sources may be in excess and detrimental to productive agriculture.

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