Chemistry Journal of Moldova

Ecological chemistry

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.
Full Text (PDF): Download

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.



Downloads: 49

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
Full Text (PDF): Download

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.


Downloads: 44

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.
Full Text (PDF): Download

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.


Downloads: 75

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.
Full Text (PDF): Download

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.


Downloads: 71

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
Full Text (PDF): Download

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.


Downloads: 47

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*
Full Text (PDF): Download

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.




Downloads: 39

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
Full Text (PDF): Download

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.



Downloads: 34

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
Full Text (PDF): Download

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.




Downloads: 29

Author(s):

Karen Ghazaryan, Hasmik Movsesyan, Naira Ghazaryan, Gor Gevorgyan, Karlen Grigoryan


Field: Ecological chemistry
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 52-57
Keywords: mining, heavy metals, soil pollution, soil improvement
Full Text (PDF): Download

DOI:
dx.doi.org/10.19261/cjm.2014.09(2).07

Graphical Abstract: 
Kajaran town is situated in the south-east of the Republic of Armenia in Syunik Marz. Developed mining and smelting industries can be observed in this area. Six the most risky sites in this area and an unpolluted site as a control were selected for the study. The content of metals was determined by means of ELAN 9000 ICP-MS System. Study results revealed the increase up to 17 times in contents of following metals: Co, Ni, Cu, Zn, Cr, Sr, Mo, Cd, Pb, As. Experiments have led us to the assumption that pollution of soils with heavy metals in the studied territory is conditioned by human activities, particularly by mining and smelting industry.


Downloads: 39

Author(s):

Tudor Lupascu, Mihail Ciobanu, Victor Botan


Field: Ecological chemistry
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 58-61
Keywords: divalent iron, divalent manganese, hydrogen sulfide, oxidation, coagulation
Full Text (PDF): Download

DOI:
dx.doi.org/10.19261/cjm.2014.09(2).08

Graphical Abstract:
 Processes of removal of divalent ions of iron and manganese and hydrogen sulfide from groundwater at various pH values and temperature were studied. Obtained results have been used in order to elaborate a process of groundwater purification from the mentioned pollutants. The use of elaborated process for natural water leads to the decrease of the content of iron, manganese and hydrogen sulfide below the maximum allowable concentrations.


Downloads: 45