Ecological chemistry

ANTIOXIDANT AND ANTIMICROBIAL PROPERTIES OF STEVIA LEAVES EXTRACTS AND SILVER NANOPARTICLES COLLOIDS

Author(s):

Iryna Laguta, Teteiana Fesenko, Oksana Stavinskaya, Oksana Dzjuba, Lesya Shpak

Field: Ecological chemistry
Type: Research paper
Issue: 2016 Volume 11, no.2
Pages: 46-51

Keywords: Stevia leaves extract, silver nanoparticles colloid, antioxidant activity, antimicrobial properties.
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DOI: dx.doi.org/10.19261/cjm.2016.11(2).08

Abstract (PDF)

Graphical Abstract: Stevia rebaudiana (Bertoni) extracts prepared from various types of raw material (leaves of plants grown ex situ and in vitro and callus culture) were found to contain different amounts of bioactive substances and differ from each other by antioxidant/reducing and antimicrobial properties and by activity in synthesis of silver nanoparticles colloids.

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ECOLOGICAL POTENTIAL OF SURFACE WATERS IN NATURAL SCIENTIFIC RESERVE “LOWER PRUT”

Author(s):

Maria Sandu, Anatol Tarita, Raisa Lozan, Natalia Zgircu, Elena Mosanu, Tatiana Goreacioc, Alexandru Zlotea, Anna Comarnitchi, Iulia Sidoren, Sergiu Turcan, Adrian Tarita

Field: Ecological chemistry
Type: Research paper
Issue: 2016 Volume 11, no.1
Pages: 21-26

Keywords: Lake Beleu, self-puriﬁcation capacity, nitriﬁcation process, BOD5 , COD-Cr.
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2016.11(1).02

Graphical Abstract: The research results have marked a low value of the self-purification capacity for Beleu Lake water, between 0.12 and 0.19, which is of 1.2-2 times smaller than the one from Prut River (0.25), correlating positively with the values of BOD5, COD-Cr and the time of biochemical oxidation of ammonium ions. The evolution of stage NH4+(NH3) → NO2- in the process of nitrification in lake water in November 2014 takes place about 25 days and the process NO2- → NO3- is more than 35 days, the duration about 2 times higher than in lake water stages from 2015 and 2.8-3.0 times higher than that of the model with water from Prut River.

The article is Open Access by CC-BY 4.0 License

Cite this article as:

M. Sandu, A. Tarita, R. Lozan, N. Zgircu, E. Mosanu, T. Goreacioc, A. Zlotea, A. Comarnitchi, I. Sidoren, S. Turcan, A. Tarita. Ecological Potential of Surface Waters in Natural Scientific Reserve “Lower Prut”. Chemistry Journal of Moldova, 2016, 11(1), pp. 21-26. DOI: dx.doi.org/10.19261/cjm.2016.11(1).02

Article Source: Ecological Potential of Surface Waters in Natural Scientific Reserve “Lower Prut”.

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STUDY OF STABLE NITROGEN FORMS IN NATURAL SURFACE WATERS IN THE PRESENCE OF MINERAL SUBSTRATES

Author(s):

Petru Spataru, Igor Povar, Elena Mosanu, Ana Trancalan

Field: Ecological chemistry
Type: Research paper
Issue: 2015 Volume 10, no.2
Pages: 26-32

Keywords: granite, expanded clay, calcium carbonate, ammonium, nitrite.
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2015.10(2).02

Graphical Abstract: The influence of substrates on the oxidation of reduced toxic forms of nitrogen in river water was investigated by laboratory modelling. Granite and expended clay accelerate the oxidation of ammonium and nitrite ions from 2 to 4 times. The presence of calcium carbonate in water hinders the oxidation of nitrogen in the polluted water.

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ESTABLISHMENT OF THE ANTIOXIDANT/ANTIRADICAL ACTIVITY OF THE INHIBITORS USING THE DPPH–RADICAL

Author(s):

Maria Gonta, Gheorghe Duca, Diana Porubin

Field: Ecological chemistry
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 118-126

Keywords: antioxidant activity, DPPH radical, inhibition rate, natural inhibitors from secondary winery materials
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Abstract (JPEG)

DOI: dx.doi.org/10.19261/cjm.2008.03(1).01

Graphical Abstract: This research paper presents the results of the investigation of antioxidant activities of various inhibitors, which are constituents of winery products: quercitin, rezveratrol, dihydroxyfumaric acid. Also, the antioxidant activity of tartaric and dihydroxyfumaric (DFH₄) acids derivatives has been determined: sodium dihydroxyfumarate, dimethylic ester of DFH₄ and dimethylic ester of tartaric acid. The enotannin extracts obtained from grape seeds have been evaluated: the non-oxidized enotannin extract Eneox and the oxidized one -Enoxil.

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DETERMINATION OF STRONTIUM IONS IN WATERS WITH A HIGH CONTENT OF SODIUM IONS

Author(s):

Tatiana Mitina, Nadejda Bondarenco, Diana Grigoras, Elena Botizat, Tudor Lupascu

Field: Ecological chemistry
Type: Research paper
Issue: 2015 Volume 10, no.1
Pages: 20-24

Keywords: water analysis, strontium ions, emission flame photometric method, atomic absorption spectroscopy.
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2015.10(1).02

Graphical Abstract: This paper dwells upon the influence of sodium ions on experimental results regarding the concentration of strontium ions in waters with a high content of sodium ions by emission flame photometry and atomic absorption spectroscopy. The metrological characteristics of both methods are evaluated.

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IMPROVEMENT OF COAGULATION PROCESS FOR THE PRUT RIVER WATER TREATMENT USING ALUMINUM SULPHATE

Author(s):

Larisa Postolachi, Vasile Rusu, Tudor Lupascu, Alexei Maftuleac

Field: Ecological chemistry
Type: Research paper
Issue: 2015 Volume 10, no.1
Pages: 25-32

Keywords: coagulation, aluminum sulphate, Jar-test method.
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2015.10(1).03

Graphical Abstract: The following factors which can improve the process of coagulation were studied: (i) the influence of stirring speed during coagulation and (ii) the influence of the concentration of the coagulant solution added in the process of coagulation. The coagulation process was studied on raw water of the Prut River. Application of the recommended procedure contribute to the reduction of the coagulant dose, the contact time, the aluminum concentration in water and the expenses for water treatment.

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DISTRIBUTION OF SOLUBLE AND INSOLUBLE CHEMICAL SPECIES OF CHROMIUM (III) AND (VI) IN AQUEOUS SOLUTIONS

Author(s):

Oxana Spinu

Field: Ecological chemistry
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 19-25

Keywords: chemical equilibrium, chromium complexes, distribution diagram, Gibbs energy
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2014.09(2).03

Graphical Abstract: On the basis of currently revised thermodynamic data for Cr(III) and Cr(VI) hydrolysis and photolytic equilibria in addition to original thermodynamic and graphical approach, used in this paper, the repartition of their soluble and insoluble chemical species has been investigated. By means of the diagrams “ΔG – pH”, the areas of thermodynamic stability of chromium(III) hydroxide have been established for a number of the analytical concentration of Cr(III) in heterogeneous mixtures. The obtained calculated results correlate well with existing experimental data.

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ECOLOGICAL CLEANING SYSTEMS FOR OLD ICONS PAINTED IN TEMPERA

Author(s):

Silvea Pruteanu, Petronela Spiridon, Viorica Vasilache, Ion Sandu

Field: Ecological chemistry
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 26-31

Keywords: degraded varnish, deposits of dirt on tempera, wash tests, solvents, vegetable extracts, decoction of dried plants, CIE colorimetry reflection L*a*b*
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2014.09(2).04

Graphical Abstract: Old icons, especially those involved in liturgical rituals are affected in time by external agents factors (temperature, humidity, light, pollution, microbiological attack, abrasion etc.), resulting changes of the appearance. Based on the literature in the field, a series of alcoholic solutions of different concentrations were made, as such or basified, which were compared with ecologic synergic systems based on organic uncolored vegetable juices and decoctions from dried plants. The cleaning effectiveness was done by visual analysis and CIE L * a * b * reflection colorimetry, this technique permitting to determine by color deviations the critical point where the patina and polychromy.

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APPLICATION OF FLOW-THROUGH THREE-DIMENSIONAL ELECTRODES FOR REGENERATION OF PLATING IRON ELECTROLYTES: 1. MATHEMATICAL MODEL

Author(s):

Alexandr Kоshev, Оlga Covaliova, Valery Varentsov

Field: Ecological chemistry
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 32-40

Keywords: electro-reduction, three-dimensional flow-through electrodes, electro-active components, numerical calculations of electrolysis processes
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2014.09(2).05

Graphical Abstract: The mathematical model of electrochemical processes distribution within the three-dimensional flow-through electrode for the system Fe(III)/Fe(II)/Fe is described in this paper, considering also the electrochemical reactions of hydrogen and molecular oxygen reduction. The results of calculations and experimental studies of iron electro-reduction are given, the analysis of the numerical modeling is provided.

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APPLICATION OF FLOW-THROUGH THREE-DIMENSIONAL ELECTRODES FOR REGENERATION OF PLATING IRON ELECTROLYTES: 2. STUDY OF PROCESS REGULARITIES BY MATHEMATICAL MODELING

Author(s):

Оlga Covaliova, Alexandr Kоshev, Valery Varentsov

Field: Ecological chemistry
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 41-51

Keywords: three-dimensional flow-through electrode, mathematical modeling, numerical calculations, polarization, local current density
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Abstract (PDF)

DOI: dx.doi.org/10.19261/cjm.2014.09(2).06

Graphical Abstract: The main regularities of the electroactive components distribution, polarization and local current density within the depth of the three-dimensional flow-through electrode have been studied using the calculation method, in dependence on the overall current density, electrode thickness and degree of its compression, solution flow velocity through the electrode, initial concentration of Fe(III) ions in the solution and electrodes brand.

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