Ecological chemistry

CHARACTERIZATION OF PROPOLIS FROM MOLDOVA'S CENTRAL REGION: CHEMICAL COMPOSITION, ANTIOXIDANT AND ANTIMICROBIAL PROPERTIES

Author(s):

Serghei Pogrebnoi, Nicolae Eremia, Dmitri Bilan, Lucian Lupascu, Natalia Bolocan, Gheorghe Duca, Svetlana Armasu, Dumitru Terteac, Vitalie Cebanu, Serghei Tincu, Alexandru Znagovan, Iulia Neicovcena, Olga Coseleva, Valerina Slanina, Fliur Macaev

Field: Ecological chemistry
Type: Research paper
Issue: 2023 Volume 18, no.1
Pages: 46-51

Keywords: propolis, GC-MS spectroscopy, liquid chromatography, antifungal activity, antibacterial activity.
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https://doi.org/10.19261/cjm.2023.924

Abstract (PDF)
Graphical Abstract: The chemical composition and antimicrobial activity of propolis ethanolic and water-ethanolic extracts from the central zone of Moldova have been investigated by GC-MS and liquid chromatography. There were found 21 amino acids, of which the most abundant were glutamic acid, alanine, leucine and isoleucine. The propolis extracts exhibited strong antioxidant (53.7 mg ascorbic acid eq./g extract or 113.4 mg Trolox eq./g extract and 87.5 mg ascorbic acid eq./g extract or 162 mg Trolox eq./g extract for ethanol, and water-ethanol extract, respectively) and antimicrobial activity (from 0.0055 up to 0.07%), suggesting their potential as natural agents for therapeutic use.

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SYNTHESIS OF QUERCETIN FUNCTIONALIZED CHITOSAN AND DETERMINATION OF ANTIOXIDANT PROPERTIES

Author(s):

Maria Gonta, Gheorghe Duca, Elena Sirbu, Stefan Robu, Larisa Mocanu

Field: Ecological chemistry
Type: Research paper
Issue: 2023 Volume 18, no.1
Pages: 38-45

Keywords: chitosan, functionalization, grafting, quercetin, antioxidant activity.
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https://doi.org/10.19261/cjm.2023.910

Abstract (PDF)
Graphical Abstract: This paper presents the synthesis of a copolymer with reducing properties obtained by functionalizing chitosan with quercetin and determining the antioxidant activity of the derivatives obtained depending on the molar mass of the polymer. For this purpose, low molecular weight chitosan was obtained by oxidizing industrial chitosan with hydrogen peroxide and functionalizing with quercetin by the covalent grafting method. The comparative antioxidant properties of the composite obtained by grafting technical chitosan with quercetin and by grafting low molecular weight chitosan were studied by the DPPH (2,2-diphenyl-1-picrylhydrazyl radical) method. The obtained results indicate that a decrease in the molecular weight of chitosan contributed to its grafting with quercetin. As a result, the functionalized polymer composite acquired a higher antioxidant activity and can be successfully used to inhibit the oxidation of various organic substrates in the cosmetic, food and pharmaceutical industries.

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BIOAVAILABILITY AND MIGRATION FEATURES OF METALS IN “BOTTOM SEDIMENTS – WATER” SYSTEM UNDER THE ACTION OF DIFFERENT ENVIRONMENTAL FACTORS

Author(s):

Petro Linnik, Vladislav Zhezherya, Rostyslav Linnik

Field: Ecological chemistry
Type: Review
Issue: 2023 Volume 18, no.1
Pages: 9-27

Keywords: water body, bottom sediment, metal speciation, metal mobility, environmental factor.
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https://doi.org/10.19261/cjm.2023.1049

Abstract (PDF)
Graphical Abstract: The results of research on the metal mobility and the peculiarities of their migration in the "bottom sediments – water" system of surface water bodies are summarized. The distribution of metals between different fractions of the solid phase of bottom sediments affects the potential metal mobility and their migration in the "bottom sediments – water" system.

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SYNTHESIS AND CHARACTERIZATION OF ZINC OXIDE AND CERIUM DIOXIDE NANOPARTICLES WITH POSSIBLE APPLICATION FOR NITRITE IONS REMOVAL IN WATERS

Author(s):

Zainab Abdul-Zahra and Rashed Rasheed

Field: Ecological chemistry
Type: Research paper
Issue: 2023 Volume 18, no.1
Pages: 28-37

Keywords: zinc oxide, cerium dioxide, nanoparticle, nitrite ion, pollutant, environment.
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https://doi.org/10.19261/cjm.2023.1027

Abstract (PDF)
Graphical Abstract: This work is dedicated to the synthesis of ZnO and CeO₂ nanopraticles with possible application for nitrite ions removal. The obtained nnaoparticles were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy and UV-visible spectroscopy. Further, the produced nanoparticles were used to adsorb NO^2- ions from aqueous solutions. The results showed that the nanoparticles which were heated at 90°C (hydroxide forms) presented a higher activity for nitrite ions removal than those that were heated at 400°C (oxide forms). This may be related to nitrite ions preferential adsorption to hydroxide forms rather than to oxide forms; in both cases (90°C and 400°C), zinc oxide nanoparticles presented higher nitrite removal activity.

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THE ROAD TO ENVIRONMENTAL CHEMISTRY IN THE REPUBLIC OF MOLDOVA PAVED BY THE ILLUSTRIOUS SCIENTIST AND RENOWNED ECOLOGIST VALERIU ROPOT

Author(s):

Tudor Lupascu and Maria Sandu

Field: Ecological chemistry
Type: Invited paper
Issue: 2022 Volume 17, no.2
Pages: 7-18

Keywords: water, wastewater, chemical composition, treatment technology, pollutant.
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https://doi.org/10.19261/cjm.2022.1018

Abstract (PDF)

Graphical Abstract: This paper presents the the main scientific and innovative results are presented, which were obtained by the talented chemist and renowned ecologist Valeriu Ropot throughout his scientific career. The results of scientific investigations are bestowed and analysed concerning the quality of the waters of the Dniester and the Prut Rivers, Dubasari reservoirs on the Dniester River, as well as the main bodies of water in the Republic of Moldova. The paper also includes the practical recommendations for reducing the negative impact on the environment, of the discharge of hundreds of thousands of tons of brine into the Dniester River as a result of the accident at the mineral fertilizer plant in the city of Stebnik, Ukraine. Moreover, the paper presents the results of studies aimed at developing methods for determining organic and inorganic pollutants in natural waters.

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NEW ASPECTS FOR THE ESTIMATION OF THE STATE OF THE NATURAL WATER

Author(s):

Viacheslav Shvydkiy, Sergei Dolgov, Alexander Dubovik, Mikhail Kozlov, Alisa Povkh, Lyudmila Shishkina, Gheorghe Duca

Field: Ecological chemistry
Type: Research paper
Issue: 2022 Volume 17, no.2
Pages: 35-42

Keywords: lecithin, hydrochemical index, water quality, UV-Vis spectroscopy, Gauss method.
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https://doi.org/10.19261/cjm.2022.973

Abstract (PDF)
Graphical Abstract: This paper presents a study of the hydrochemical composition and physicochemical properties of natural water samples from various sources in the Voronezh and Moscow regions. Two model systems are proposed for assessing the state of the aquatic environment: UV spectroscopy with spectrum decomposition by the Gauss method and spontaneous aggregation of lecithin in a polar medium. Based on the performed investigation, it was determined that the size of lecithin aggregates decreases, and the value of their zeta potential increases with an increase in the content of hydrophobic compounds in natural water.

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PREPARATION OF COMPOSITES BASED ON CAFFEIC ACID AND FUMED SILICA AND EVALUATION OF THEIR ANTIOXIDANT AND ANTIMICROBIAL PROPERTIES

Author(s):

Oksana Stavinskaya, Iryna Laguta, Pavlo Kuzema, Iryna Skorochod, Alla Roy, Ivan Kurdish

Field: Ecological chemistry
Type: Research paper
Issue: 2022 Volume 17, no.2
Pages: 43-49

Keywords: caffeic acid, fumed silica, composite, antioxidant, radical scavenger, antimicrobial activity.
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https://doi.org/10.19261/cjm.2022.984

Abstract (PDF)
Graphical Abstract: The work was aimed at preparing the CA+A300 composite consisting of caffeic acid (CA) and fumed silica (A300) and at comparing the properties of CA in the solution and in the composite. The results showed that the solution and the composite are effective antioxidant/antimicrobial agents and that inclusion of CA in the CA+A300 composite provides its gradual release into solutions and reaction mixtures, thus ensuring a prolonged action of the compound.

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OBTAINING OF COMPLEX MINERAL FERTILIZER BY PHOSPHOGYPSUM CONVERSION WITH AMMONIUM NITRATE

Author(s):

Anna Ivanchenko, Dmytro Yelatontsev, Anatoliy Savenkov, Olena Nazarenko, Viktoria Kundirenko

Field: Ecological chemistry
Type: Research paper
Issue: 2022 Volume 17, no.1
Pages: 18-23

Keywords: hosphogypsum, ammonium nitrate, complex mineral fertilizer, wet conversion.
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DOI: http://dx.doi.org/10.19261/cjm.2021.902

Abstract (PDF)
Graphical Abstract: An environmentally friendly method for phosphogypsum processing into N,Ca,S,P-fertilizers is proposed. Thus, was obtained a complex liquid N,Ca,S,P-fertilizer with the content of nutrients (% wt.) N:Ca:S:P = 56:26:12:6 in the dry product, and 16.8:3.6:7.8:1.8 in the liquid phase. The obtained fertilizer increased the yield of radish by 7.16% compared to the control. The advantage of the proposed method is reducing the cost of the fertilizer, increasing its nutritional value, and obtaining useful products from the waste.

Downloads: 92

APPLICATION OF THE MONTE-CARLO METHOD TO THE DESCRIPTION OF THE DYNAMICS OF THE SPREAD OF SALVO POLLUTION COMPLICATED BY ADSORPTION

Author(s):

Serghei Travin

Field: Ecological chemistry
Type: Research paper
Issue: 2021 Volume 16, no.2
Pages: 46-51

Keywords: Monte-Carlo method, mass transfer, adsorption, spatial-time dynamics, computational efficiency.
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DOI: http://dx.doi.org/10.19261/cjm.2021.920

Abstract (PDF)

Graphical Abstract: The possibilities of application of the Monte-Carlo method for simulating the consequences of pollutants emissions with specific adsorption on the underlying surface were considered. Effective methods of obtaining kinetic curves for the concentration of a pollutant for a selected square on the field and constructing contamination profiles for a specified time are analysed. The estimation of the necessary parameters of the model for obtaining high-quality kinetic curves was performed and recommendations for their optimization are given. Specific fronts for the spot propagation were obtained and visualised.

Downloads: 89

HYDROGEN PEROXIDE IN ECOLOGICAL AND ENVIRONMENTAL CHEMISTRY

Author(s):

Gheorghe Duca

Field: Ecological chemistry
Type: Review
Issue: 2021 Volume 16, no.2
Pages: 28-45

Keywords: hydrogen peroxide, redox process, catalysis, transition valence metal ion, intermediate specie.
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DOI: http://dx.doi.org/10.19261/cjm.2021.918

Abstract (PDF)

Graphical Abstract: This review paper is focused on the detailed consideration of the structure, properties and reactions of H₂O₂. The paper highlights the importance of revealing these processes’ mechanisms, since they have been insufficiently studied so far, or the related data have a fragmentary and incomplete character. A special attention is given to catalytic oxidation reactions, formation and properties of intermediates, their role in the natural environment.

Downloads: 85