Chemistry Journal of Moldova

Ecological chemistry

MAGNETO-SENSITIVE CARBON-INORGANIC COMPOSITES BASED ON PARTICLEBOARD AND PLYWOOD WASTES

Author(s):

Mariia Galaburda, Viktor Bogatyrov, Dariusz Sternik, Olena Oranska, Mykola Borysenko, Ivan Škorvánek, Ewa Skware, Anna Deryło-Marczewska, Volodymyr Gun’ko


Field: Ecological chemistry
Type: Research paper
Issue: 2021 Volume 16, no.1
Pages: 68-78
Keywords: sawdust, activated carbon, carbon-metal composite, magneto-sensitive sorbent.
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DOI: http://dx.doi.org/10.19261/cjm.2021.811

Abstract (PDF) 
Graphical Abstract: The conversion of metal-modified (Fe, Co) sawdust into magneto-sensitive porous composites using thermal carbonization process in an inert atmosphere was successfully achieved. The as-prepared samples were characterized using nitrogen adsorption, X-ray diffraction, scanning electron microscopy and thermal analysis methods. The obtained results show that the structural and morphological characteristics of the obtained composites depend strongly on the metal precursor’s types. All samples exhibited a good magnetic property and can be easily separated from liquids by an external magnet.


 
Downloads: 24

INVESTIGATION OF VARIOUS INFLUENCING FACTORS OF HYDROTHERMAL SYNTHESIS OF ANALCIME ZEOLITE

Author(s):

Gunel Mamedova, Gunel Nasirli


Field: Ecological chemistry
Type: Research paper
Issue: 2021 Volume 16, no.1
Pages: 60-67
Keywords: analcime, hydrothermal synthesis, natural mineral, zeolite, crystallization.
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DOI: http://dx.doi.org/10.19261/cjm.2021.792
 
Abstract (PDF)
Graphical Abstract: This study presents an investigation of the use of the natural mineral of Nakhchivan Autonomous Republic to produce analcime zeolite of potential practical importance. The influence of temperature and crystallization time, the concentration of alkaline solution and mineralizer on the process of synthesis of analcime has been evaluated. The optimal conditions established for the synthesis of pure analcime with a 100% degree of crystallinity are as follows: temperature of 180°C, alkaline and mineralizer solution of 10-15% KOH and 5-10% KCl and processing time of 50 hours. It has been shown that the presence of the KCl mineralizer promotes the production of pure analcime with a 100% crystallinity, and the natural mineral of Nakhchivan represents a good source for the synthesis process.


 

Downloads: 73

SENSITIZED PHOTOLYSIS OF THIOGLYCOLIC ACID IN AQUATIC ENVIRONMENT

Author(s):

Angela Lis, Viorica Gladchi, Gheorghe Duca, Sergey Travin


Field: Ecological chemistry
Type: Research paper
Issue: 2021 Volume 16, no.1
Pages: 46-59
Keywords: photochemical transformation, thioglycolic acid, humic substance, kinetic parameter, natural water.
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DOI: http://dx.doi.org/10.19261/cjm.2021.796
 
Abstract (PDF)
Graphical Abstract: The photochemical transformations of thioglycolic acid using model systems was studied by varying the irradiation sources and the kinetic parameters were determined. It was found that thioglycolic acid undergoes destruction on induced photolysis in the presence of humic substances, and its half-life can be estimated as 10-14 days, depending on weather conditions (cloudiness, time of day, season etc.). Results obtained in the course of this study on model systems were transferred to natural waters, and it was concluded that thioglycolic acid has a positive influence on the chemical self-purification processes of water, in the natural aquatic environment. This is manifested by increasing the self-purification capacity of water, due to the generation of active oxygen species, which lead to the degradation not only of this thiol, but of other pollutants present in aquatic environment, as well. At the same time, the products of the transformations are harmless to the aquatic environment and hydrobionts.


 


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VARIATIONS OF PHOSPHORUS, SULPHUR AND NITROGEN CONTENT IN LICHENS IN THE FORMER MANUFACTURING AREAS

Author(s):

Vitālijs Lazarenko, Zenta Balcerbule, Vita Rudoviča, Arturs Vīksna


Field: Ecological chemistry
Type: Research paper
Issue: 2020 Volume 15, no.2
Pages: 38-44
Keywords: phosphorus, nitrogen, sulphur, lichen, soil.
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DOI: http://dx.doi.org/10.19261/cjm.2020.751

Abstract (PDF)
Graphical Abstract: The aim of this research work was to evaluate the pollution level of phosphorus, sulphur and nitrogen in the former manufacturing areas (the former Kuprava drainage pipe factory and landfill site) and compare it with the Sita forest area levels using lichens as bioindicators. Additionally, the correlation between the content of these elements in lichens and soil was examined. The research results show that in the former drainage pipe factory area and landfill site, the levels of phosphorus, sulphur and nitrogen content were elevated in comparison with Sita forest. In the case of phosphorus and nitrogen contents, a positive correlation was observed between soil and lichen samples. 


 

Downloads: 65

APPLICATION OF INNOVATIVE PROCESSES FOR GOLD RECOVERY FROM ROMANIAN MINING WASTES

Author(s):

Stefano Ubaldini, Igor Povar, Tudor Lupascu, Oxana Spinu, Francesca Trapasso, Daniele Passeri, Serena Carloni, Daniela Guglietta


Field: Ecological chemistry
Type: Research paper
Issue: 2020 Volume 15, no.2
Pages: 29-37
Keywords: mining waste, gold, thiosulphate leaching, activated carbon, adsorption, desorption.
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DOI: http://dx.doi.org/10.19261/cjm.2020.718

Abstract (PDF)
Graphical Abstract: The application of a new hydrometallurgical process for gold extraction by thiosulphate leaching from Romanian mining wastes, coming from Balan and Deva deposits, was studied. There was obtained 85% of Au extraction after leaching; moreover, an integrated flow-sheet, including recycling of process solution and carbon, was outlined, based on results obtained at a laboratory scale, using a schematic chemical circuit of treatment. Global recovery of the process (leaching-adsorption-desorption-electrodeposition) of about 75-80% of Au was achieved. The developed integrated flow-sheet, allows to recycle the reagents during the process, with a loss of only 5-10%, in particular thiosulphate and alcohol, for each complete circuit of treatment.


 

Downloads: 52

ORGANOCHLORINE PESTICIDES RESIDUES IN SOIL OF SOROCA DISTRICT, REPUBLIC OF MOLDOVA

Author(s):

Elena Culighin


Field: Ecological chemistry
Type: Research paper
Issue: 2020 Volume 15, no.1
Pages: 41-50
Keywords: pesticide, hexachlorocyclohexane, dichlorodiphenyltrichloroethane, soil, Republic of Moldova.
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DOI: http://dx.doi.org/10.19261/cjm.2020.672   
 
Abstract (PDF)
Graphical Abstract: The level, composition, and distribution of hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) residues were determined by GC-ECD technique in soil samples from the Soroca district, Republic of Moldova. The concentrations of DDTs and HCHs were up to 1100 and 640 mg/kg, respectively. The high concentration and the degradation rates of the pesticides in soil suggest that the contaminated sites are acting as continuous sources of pollution for the environment. Thus, remediation measures are required to reduce the level of the contaminants in soil.


 

Downloads: 204

SYNTHESIS OF DIFFERENT STRUCTURAL TYPES OF ZEOLITES IN THE HALLOYSITE-DOLOMITE-OBSIDIAN SYSTEM

Author(s):

Gunel Mamedova


Field: Ecological chemistry
Type: Research paper
Issue: 2020 Volume 15, no.1
Pages: 31-40
Keywords: hydrothermal synthesis, zeolite, gismondine, laumontite, levyne.
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DOI: http://dx.doi.org/10.19261/cjm.2020.664   
 
Abstract (PDF)
Graphical Abstract: Gismondine, laumontite and levyne type zeolites have been synthesized based on the natural minerals of Nakhchivan and the optimal crystallization conditions have been established. The initial components and the reaction products have been examined by X-ray diffraction, thermogravimetric and elemental analysis. It was found that changes in the temperature, alkalinity, ratio of starting components and time of processing of the reaction have different effects on the rate of formation of products, on their degree of crystallinity and on the phase purity of the obtained zeolite.


 

Downloads: 509

TOWARD A MULTIDISCIPLINARY STRATEGY FOR THE CLASSIFICATION AND REUSE OF IRON AND MANGANESE MINING WASTES

Author(s):

Daniela Guglietta, Girolamo Belardi, Giovanna Cappai, Barbara Casentini, Alicia Godeas, Stefano Milia, Daniele Passeri, Rosamaria Salvatori, Adalgisa Scotti, Vanesa Silvani, Emanuela Tempesta, Stefano Ubaldini, Francesca Trapasso


Field: Ecological chemistry
Type: Research paper
Issue: 2020 Volume 15, no.1
Pages: 21-30
Keywords: mining waste, metal recovery, recycle, remote sensing analysis.
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DOI: http://dx.doi.org/10.19261/cjm.2019.650   

Abstract (PDF)
Supplementary Material (PDF)
Graphical Abstract: The aim of this paper is to evaluate an integrated multidisciplinary strategy for the characterization of mining waste, their possible recycling and reuse. The use of Fe-Mn rich wastes in arsenic removal and phosphorus recovery from water and the phytoextraction potential of metals and their possible recovery from biomass are evaluated.


 

Downloads: 74

PESTICIDES RESIDUE DETERMINATION IN VEGETABLES AND FRUITS COMMONLY USED IN REPUBLIC OF MOLDOVA AND ESTIMATION OF HUMAN INTAKE

Author(s):

Raisa Sircu, Gheorghii Turcanu, Nicolae Opopol, Iurie Pinzaru, Tatiana Manceva, Raisa Scurtu


Field: Ecological chemistry
Type: Research paper
Issue: 2019 Volume 14, no.2
Pages: 62-71
Keywords: pesticide residue, fruit, vegetable, estimated daily intake, risk assessment.
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DOI: http://dx.doi.org/10.19261/cjm.2019.584   
 
Abstract (PDF)
Graphical Abstract: A total of 5206 samples from twenty-one different vegetables and fruits were collected. Residues of pesticides in concentrations exceeding the maximum residue levels were found in 22.9% of analysed samples. Thirteen insecticides, four fungicides, two acaricides and one herbicide were detected in the analysed samples. The highest value of hazard index was calculated for diazinon – 0.15. The obtained results show that the long-term consumption of vegetables and fruits could pose a health risk for the population of the Republic of Moldova.


 


Downloads: 77

EFFECT OF TEMPERATURE ON GREEN SYNTHESIS OF SILVER NANOPARTICLES USING VITEX AGNUS-CASTUS EXTRACT

Author(s):

Oksana Stavinskaya, Iryna Laguta, Tetiana Fesenko, Marina Krumova


Field: Ecological chemistry
Type: Short communication
Issue: 2019 Volume 14, no.2
Pages: 117-121
Keywords: nanoparticle, silver, green synthesis, Vitex agnus-castus extract.
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DOI: http://dx.doi.org/10.19261/cjm.2019.636   
 
Abstract (PDF)
Graphical Abstract: Silver nanoparticles colloids were prepared using the extract from the leaves of Vitex agnus-castus. The effect of temperature on the reduction of silver ions and on the growth of silver nanoparticles was followed by measuring the intensity of the surface plasmon resonance band in the UV spectra. It was found that fast reduction of silver ions occurs even at 40°C, while effective synthesis of silver nanoparticles requires elevated temperatures of 60-80°C.


 


Downloads: 105