scholarly journals OBTAINING DERIVATIVES OF HUMIC SUBSTANCES FROM OXIDIZED COAL AND STUDY OF PHYSICO-CHEMICAL AND ADSORPTION PROPERTIES

2020 ◽  
Vol 6 (444) ◽  
pp. 57-64
Author(s):  
B.T. Yermagambet ◽  
◽  
M.K. Kazankapova ◽  
Zh.M. Kassenova ◽  
A.T. Nauryzbayeva ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Humic Substances ◽  
Humic Acids ◽  
Aqueous Media ◽  
Amino Groups ◽  
Chelate Complexes ◽  
High Adsorption ◽  
Oxidized Coal ◽  
Physico Chemical ◽  
Derivatives Of

In the work, a chemical analysis of humic substances based on oxidized coal of the Maikuben basin (Kazakhstan) is carried out. Humic acids were obtained on the basis of potassium humates by acidification with a 20% acid solution to pH = 3-4.5. The optimal conditions for obtaining nitrohumic acids from oxidized coals are: the duration of the process is 3 hours, the ratio of S:L = 1:5, the content of nitric acid is 64%, sulfuric acid is 96% and the composition of the nitrating mixture is 1:1 (g/g). Amminohumic derivatives were obtained in the presence of a 3% aqueous solution of ammonia using mechanical activation and ultrasonic treatment. The samples obtained were tested as an adsorbent for water purification from heavy metals. Humic acids and aminohumate showed the highest degrees of purification for zinc (99.0-100.0%) and cadmium (80.0-96.7%), and nitrohumic acid showed a high adsorption capacity for heavy metals like copper - 100.0 % and lead 82.9%. This is due to the fact that when interacting with heavy metals, humic acids and their derivatives (amino and nitro) form chelate complexes due to carboxyl, phenolic, nitro and amino groups. As a result of the study, the possibility of using them as non-toxic available sorbents for the purification of heavy metals in aqueous media has been shown.

Rational Use of Oxidized Coals

2019 ◽  
Vol 23 (5) ◽  
pp. 22-27
Author(s):  
T.V. Shevchenko ◽  
Yu. V. Ustinova ◽  
A.M. Popov ◽  
Ya.A. Novikova ◽  
Sh.A. Fairushin
Keyword(s):  
Humic Acids ◽  
Chemical Properties ◽  
Animal Husbandry ◽  
Agricultural Products ◽  
Rational Use ◽  
New Methods ◽  
Oxidized Coal ◽  
Physico Chemical ◽  
Arable Farming ◽  
Effective Use

The ways of processing large-tonnage coal mining waste – oxidized coal into technical and agricultural products – are presented based on the rational and efficient use of some modified physico-chemical properties of original coal materials. Studied ways of rational use of oxidized coal in agriculture, based on effective use of coal derived humic acids: as an additive of its crushed fractions on the fields for growing grain and tuberous plants, as well as for the production of humic preparations (fertilizes, biological active additives based on humic acids for arable farming and animal husbandry). Proposed new methods of reclamation of disturbed lands with the help of microbiological destructors of oxidized coal.

scholarly journals Functionalized Derivatives of Benzo-Crown Ethers. Part 4. Antifungal Macrocyclic Supramolecular Complexes of Transition Metal Ions Acting as Lanosterol-14-α -Demethylase Ihibitors

1999 ◽  
Vol 6 (2) ◽  
pp. 101-110 ◽  
Author(s):  
Mihai Barboiu ◽  
Claudiu T. Supuran ◽  
Andrea Scozzafava ◽  
Cornelia Guran ◽  
Paula Diaconescu ◽  
...  
Keyword(s):  
Metal Ions ◽  
Coordination Compounds ◽  
Antifungal Agents ◽  
Transition Metal Ions ◽  
Supramolecular Complexes ◽  
Amino Groups ◽  
Candida Spp ◽  
Physico Chemical ◽  
Antifungal Action ◽  
Derivatives Of

Poly- and mononuclear metal complexes of 2,3,11,12-bis[4-(10-aminodecylcarbonyl)]benzo-18- crown-6 (L) and Cu(II); Ni(II); Co(II) and Cr(III) have been synthesized and characterized by standard physico-chemical procedures. In the newly prepared complexes the crown moiety oxygen atoms of the macrocyclic host did not generally interact with metal ions, whereas the two amino groups of the ligand always did. Several of the newly synthesized compounds act as effective antifungal agents against Aspergillus and Candida spp., some of them showing activities comparable to ketoconazole, with minimum inhibitory concentrations in the range of 0.3−0.5 μg/mL . The mechanism of antifungal action of these coordination compounds is probably connected to an inhibition of lanosterol-14-α -demethylase, a metallo-enzyme playing a key role in sterol biosynthesis in fungi, bacteria and eukariotes.

scholarly journals The influence of humic acid quality on the sorption and mobility of heavy metals

2011 ◽  
Vol 49 (No. 12) ◽  
pp. 565-571 ◽  
Author(s):  
G. Barančíková ◽  
J. Makovníková
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Actual Structure ◽  
Mobile Forms ◽  
Fraction I ◽  
High Degree

Mobile and potentially mobile forms of heavy metals are probably one of the most important toxic hazards in the environment. Besides pH, which is a factor influencing the mobility/availability of heavy metals to the greatest extent, the content and mainly the quality of soil organic matter play a very important role in the evaluation of heavy metal behaviour in the environment. The fraction of metals bound to organic compounds is exclusively associated with humic substances and particularly with humic acids (HA). A relationship between the parameters reflecting the actual structure of humic acids and mobile or potentially mobile fractions of heavy metals was studied in 12 soil localities representing different soil types. It can be stated on the basis of the acquired data that heavy metals tend to form complexes with soil organic matter that are different for each metal. The results suggest that copper is bound mainly in an unavailable form (significant correlations of fraction IV with HA parameters) and cadmium prefers exchangeable forms (significant correlations of fraction I with HA parameters) and is more available. It can be assumed on the basis Spearman’s correlations that mobile fractions of cadmium are predominantly bound to the aliphatic part of humic substances, and copper prefers strong bonds to humic acids with a high degree of humification.

The function of carboxyls in the structure of humic acids to binding of organic substances

2020 ◽  
Author(s):  
Jiri Smilek ◽  
Anna Belusova ◽  
Michal Kalina ◽  
Petr Sedlacek
Keyword(s):  
Humic Substances ◽  
Organic Compounds ◽  
Humic Acids ◽  
Hydrophobic Interactions ◽  
Organic Dyes ◽  
Strong Impact ◽  
Spectroscopic Techniques ◽  
Surface Active Agents ◽  
Physico Chemical ◽  
Surface Active

<p>The humic substances, the major and the most important part of soil organic matter, are responsible for the immobilization of organic compounds (e.g. heavy metal ions, organic dyes, surface active agents, etc.) in the soil. Unfortunately, there are a lot of gaps in the knowledge in the complex mechanism of binding of organic charged compounds by humic substances.</p><p>The unconventional diffusion and dialysis (transport) techniques have been developed for the purpose of study on the interactions between humic substances and organic charged substances.  In our contribution we are focusing on one fraction of humic substances – humic acids. The binding between humic acids with/without selectively blocking of carboxylic functional groups (methylation by –CH3) with organic charged compounds (e.g. organic dyes, surface active agents) has been studied by diffusion and dialysis approach using the spectroscopic techniques as analytical method. The strong impact of methylation on the positive affinity of humic acids towards organic compounds has been expected. These expectations were not confirmed by diffusion and dialysis techniques. The role of carboxyls in the structure of humic acids is not so essential as was expected and mentioned in the literature. The other effects (e.g. hydrophobic interactions, pi-pi stacking, etc.) are more important in the binding of organic compounds as was expected. The positive binding as well as kinetics of this process is also strongly depending on the physico-chemical circumstances of the system (e.g. pH, ionic strength, temperature, etc.).</p>

Actinide Sorption onto Silica in the Presence of Humic Substances: Proposal of Retentionmechanisms

1991 ◽  
Vol 257 ◽  
Author(s):  
N. Labonne ◽  
V. Moulin ◽  
D. Stammose
Keyword(s):  
Ionic Strength ◽  
Humic Substances ◽  
Humic Acids ◽  
Surface Complexation ◽  
Complexing Agents ◽  
Complexation Constants ◽  
Surface Complexation Model ◽  
Physico Chemical ◽  
Ph Range ◽  
Geological Formations

ABSTRACTThe experimental investigation and modelling of radionuclides sorption processes is an essential part of safety analyses of an underground repository of radioactive wastes in geological formations. Physico—chemical phenomena at oxide/solution interfaces have been studied in the case of the system constituted by amorphous silica and americium (III) in the presence of humic substances as organic complexing agents. The retention behaviour of Am(III) onto silica appears dependent on pH, ionic strength and in particular humic concentration. At a ionic strength of 0.1 M, the presence of low concentration of humic acids (1 mg/l) enhances the Am(III) retention in the pH range 3-5.5, whereas at higher pH, its uptake is largely decreased. At lower ionic strength (0.001 M), Am(III) retention on silica is highly lowered, in the pH range 3-7 in the presence of humic acids. Reversibility experiments show the desorption of americium in the absence of humic substances, and also the desorption of the humics on the silica with respect of the pH. The surface complexation model has been applied to our results in the different systems and apparent surface complexation constants have been determined.

The change in agrochemical indicators of soil fertility under the influence of heavy metal contamination

2016 ◽  
Vol 2 (91) ◽  
pp. 17-21
Author(s):  
S. H. Korsun ◽  
N. I. Dovbash
Keyword(s):  
Heavy Metals ◽  
Forest Soil ◽  
Heavy Metal Contamination ◽  
Gray Forest Soil ◽  
Mineral Fertilizers ◽  
Background Concentration ◽  
Physico Chemical ◽  
Natural Background Concentration ◽  
Nitrogen Phosphorus ◽  
Hydrolytic Acidity

The aim of the study was to establish changes in the physico-chemical and agrochemical characteristics of gray forest large-clay loamy soil, depending on the contamination of ecotopes by heavy metals. Methods. Field, laboratory, mathematical and statistical. Results. The results of the study of the soil of areas with an over-dimensioned content of heavy metals and the transformation of agrochemical characteristics of gray forest soil in the cultivation of corn for grain. It was established that under conditions of systematic application of mineral fertilizers in agrocenoses, an increase in the lead concentration to 100 mg/kg, cadmium to 2,0, zinc to 50 mg/kg in gray forest soil did not result in a decrease in the amount available forms of nitrogen, phosphorus, potassium by plants, compared with the natural background. Concentration of lead in the amount of 1000 mg/kg, cadmium – 20, zinc – 500 mg/kg marked an increase in exchange and hydrolytic acidity and loss of humus.

Mercury Removal from Wastewater by Steamed Hoof Powder

1999 ◽  
Vol 40 (7) ◽  
pp. 109-116 ◽  
Author(s):  
M. H. Ansari ◽  
A. M. Deshkar ◽  
P. S. Kelkar ◽  
D. M. Dharmadhikari ◽  
M. Z. Hasan ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Light Metal ◽  
Mercury Removal ◽  
High Adsorption ◽  
Surface Sites ◽  
Ph Values ◽  
High Adsorption Capacity

Steamed Hoof Powder (SHP), size < 53μ, was observed to have high adsorption capacity for Hg(II) with >95% removal from a solution containing 100 mg/L of Hg(II) with only 0.1% (W/V) concentration of SHP. The SHP has good settling properties and gives clear and odour free effluent. Studies indicate that pH values between 2 and 10 have no effect on the adsorption of Hg(II) on SHP. Light metal ions like Na+, K+, Ca2+ and Mg2+ up to concentrations of 500 mg/L and heavy metals like Cu2+, Zn2+, Cd2+, Co2+, Pb2+, Ni2+, Mn2+, Cr3+, Cr6+, Fe2+ and Fe3+ up to concentrations of 100 mg/L do not interfere with the adsorption process. Anions like sulphate, acetate and phosphate up to concentrations of 200 mg/L do not interfere. Chloride interferes in the adsorption process when Hg(II) concentration is above 9.7 mg/L. The adsorption equilibrium was established within two hours. Studies indicate that adsorption occurs on the surface sites of the adsorbent.

Utilisation of Biomass and Hybrid Biochar from Elephant Grass and Low Density Polyethylene for the Competitive Adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) from Aqueous Media

2020 ◽  
Vol 13 ◽  
Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Contact Time ◽  
Competitive Adsorption ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Polluted Water ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Elephant Grass

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.

scholarly journals Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1067
Author(s):  
Aleksandra Ukalska-Jaruga ◽  
Romualda Bejger ◽  
Guillaume Debaene ◽  
Bożena Smreczak
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Agricultural Soils ◽  
Fulvic Acids ◽  
Sorption Properties ◽  
Aliphatic Chains

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties.

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