StatusThe thesis was presented on the 7 September, 2018
Approved by NCAA on the 23 November, 2018
Abstract– 0.86 Mb / in romanian
4.31 Mb /
The thesis consists of the introduction, four chapters in which are presented theoretical notions and experimentally obtained results, general conclusions and recommendations, bibliography of 218 titles, 7 annexes, 121 pages of basic text, 31 tables and 72 figures. The obtained results are published in 32 scientific papers. .
Research field: 145.01 - Ecological Chemistry The aim of the work is to elucidate the peculiarities of the process of removal (adsorption/ oxidation) of nitrite ions from water in the presence of carbonaceous adsorbents.
Objectives: analysis of the underground water quality in the Republic of Moldova and highlighting of the excessive concentrations of nitrogen compounds in water; highlighting the methodological particularities for the determination of nitrate ions in the presence of nitrite ions in water; modification of carbonaceous adsorbents by oxidation with concentrated nitric acid and /or impregnation with metals; assessing surface characteristics of carbonaceous adsorbents by standard methods; studying the removal (adsorption /oxidation) of nitrite ions on carbonaceous adsorbents under static and dynamic conditions; testing of carbonaceous adsorbents for removal of nitrite ions from natural waters.
Scientific novelty. For the first time, the influence of acidic functional groups from active carbons surfaces on the nitrite ion adsorption process was studied. For the first time, carbonaceous adsorbents have been tested for removal of nitrite ions from natural (underground) water.
The solved scientific problem consists in identifying the particularities of the process of removal (adsorption/ oxidation) of nitrite ions from the water on carbonaceous adsorbents, which allows elaboration and optimization of the treatment/purification processes of natural waters.
Theoretical significance of the work. The obtained results contribute to the consolidation of knowledge about surface chemistry of carbonaceous adsorbents and their influence in the process of removal (adsorption/ oxidation) of pollutants from water. Research demonstrates the important role of strong acidic functional groups on the surface of active carbons in the adsorption process of nitrite ions from water.
Applied value of the work. Testing the process of removing nitrite ions in the presence of carbonaceous adsorbents and oxygen from air on natural water sources, demonstrates the possibility of using it for water treatment. In this case it is recommended to use acidic adsorbents rich in strong carboxylic acid functional groups. Methodological peculiarities have been highlighted, and modifications of the method of determination of nitrate ions in the presence of nitrite ions was recommended, by applying a reducing agent. It is proposed to use the Na2SO4/Zn reducing agent, which is efficient and less polluting agent, compared to other reducing agents based on Cd, V, Mn, etc.
Implementation of scientific results. The studied carbonaceous adsorbents were tested for the removal of nitrite ions from groundwater (village Isacova, district Orhei). The method of determination of nitrate ions in the presence of nitrite ions in water, elaborated in the thesis, was used in the research.
Under consideration  :