Facultatea de Chimie şi Tehnologie Chimică / Faculty of Chemistry and Chemical Technology
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Item ASSESSMENT OF KINETIC PARAMETERS IN THE WATERS OF THE NISTRU COURSE IN THE SECTION NASLAVCEA – DUBASARI(2006) Bunduchi, Elena; Duca, Gheorghe; Gladchi, Viorica; Goreaceva, Nelli; Mardari, IgorThe current work represents the results of a monitoring executed on Nistru River waters between October 2003 and September 2005. The water quality was evaluated on the basis of such kinetic indicators as redox state and capacity of inhibition. The obtained results shows that Nistru River water in the segment Naslavcea village – Dubasari barrage are continuously polluted with reducing substances that diminish the H2O2 content, that actually determines the redox state of natural waters and the content of free radicalsItem THE STUDY OF THE BUFFERING CAPACITY OF SEVERAL WATER OBJECTS IN THE REPUBLIC OF MOLDOVA(2009) Lis, Angela; Duca, Gheorghe; Bunduchi, Elena; Gladchi, Viorica; Goreaceva, NelliThe Republic of Moldova is situated among countries with relatively poor water resources, therefore their protection and rational use remains a national problem. Due to its geographic position, the Republic of Moldova is subjected to transboundary pollution. The current work represents the estimation of the buffering capacity on the Dniester River waters and its tributaries between November 2008 and October 2009. Decrease of the buffering capacity in water basins leads to disruption of the normal activity of aquatic biota, by increasing the toxicity in their living environment. On the basis of the results of measurements, suggestions for the improvement of the situation will be made and for enhancing public awareness and public authorities involvement.Item THE SCHOOL OF ECOLOGICAL CHEMISTRY FOUNDED BY ACADEMICIAN GHEORGHE DUCA(2009) Lupașcu, Tudor; Gonța, Maria; Gladchi, VioricaThis review details the most important achievements in the field of ecological chemistry and environmental protection, obtained at the State University of Moldova and Institute of Chemistry of the Academy of Sciences of Moldova. The main research directions are described, as well as main scientific laboratories and centres of these two institutions.Item THE STUDY OF REDOX CONDITIONS IN THE DNIESTER RIVER(2008) Gladchi, Viorica; Goreaceva, Nelli; Duca, Gheorghe; Bunduchi, Elena; Romanciuc, Lidia; Mardari, Igor; Borodaev, RuslanThe work presented in the paper discusses the contribution of the Novodnestrovsc water system to the formation of redox conditions in the lower Dniester. The conclusions were drawn on the basis of a long-term protocol of analyses that included the analysis of the oxygen regime, evaluation of the content of hydrogen peroxide,rH2, biological oxygen demand as well as other additional parameters.Item ESTIMATION OF THE NATURAL WATER SELF-PURIFICATION CAPACITY FROM THE KINETIC STANDPOINT(2008) Duca, Gheorghe; Bunduchi, Elena; Gladchi, Viorica; Romanciuc, Lidia; Goreaceva, NelliThe current paper contains a synthesis of the processes of chemical auto-purification that take place in natural waters; examples of mechanisms of such processes occurring with participation of dissolved organic matter, oxidants of the biogeochemical cycle of oxygen and of transition metals including copper and iron are presented. The kinetic indicators of natural water quality are presented as well.Item PĂTRUNDEREA ŞI TRANSFORMĂRILE CHIMICE ALE SUBSTANŢELOR ANTIBACTERIENE ÎN MEDIUL ÎNCONJURĂTOR(2005) Boldescu, Veaceslav; Gladchi, VioricaRecently, pharmaceuticals and personal care products (PPCPs) with their metabolites have been detected as common contaminants in surface waters throughout the world. The most frequently detected compounds were hormones, antibiotics, analgesics, fragrances, disinfectants, diagnostic agents, sunscreen agents, tranquilizers. The major possible impact of antibiotics and other antibacterial products is development of resistant bacteria and potential to disturb environmental bacterial community and processes. One of the main physico-chemical processes of PPCPs degradation is considered photolysis. This work is dedicated to the photodegradation of the antibiotic oxytetracycline hydrochloride. The study has been performed with and without addition of the copper (II) ions which are main catalysts in natural redox processes. It has been found that the photodegradation rate of oxytetracycline hydrochloride for the model system with addition of Cu2+ is lower than for the system without addition of Cu2+. Moreover, there exists a qualitative difference between transformational products formed with and without addition of Cu2+. It is obvious that the formation of Cu-antibiotic complexes causes these differences in the rates and products. Obtained results emphasize the importance of identifying the transformation products and the degradation rates of PPCPs in the presence of natural transition ions(Cu2+, Fe3+, Mn4+) and other cations (Ca2+, Mg2+), which can form complexes with PPCPs, in order to obtain results closer to the real environmental conditions.Item ROLUL ORGANIZAŢIILOR OBŞTEŞTI ÎN EDUCAŢIA ECOLOGICĂ A POPULAŢIEI(Academia de Ştiinţe a Moldovei, 2005) Gladchi, Viorica; Goreaceva, Nelli; Romanciuc, Lidia; Mardari, Iurie; Borodaev, Ruslan; Bunduchi, ElenaItem THE INFLUENCE OF SOME ORGANIC ACIDS ON THE RADICAL SELF-PURIFICATION PROCESS OF THE AQUATIC MEDIUM(Academia de Ştiinţe a Moldovei, 2005) Bunduchi, Elena; Gladchi, VioricaItem PĂTRUNDEREA ŞI TRANSFORMĂRILE CHIMICE ALE SUBSTANŢELOR ANTIBACTERIENE ÎN MEDIUL ÎNCONJURĂTOR(2005) Boldescu, Veaceslav; Gladchi, VioricaSummary: Recently, pharmaceuticals and personal care products (PPCPs) with their metabolites have been detected as common contaminants in surface waters throughout the world. The most frequently detected compounds were hormones, antibiotics, analgesics, fragrances, disinfectants, diagnostic agents, sunscreen agents, tranquilizers. The major possible impact of antibiotics and other antibacterial products is development of resistant bacteria and potential to disturb environmental bacterial community and processes. One of the main physico-chemical processes of PPCPs degradation is considered photolysis. This work is dedicated to the photodegradation of the antibiotic oxytetracycline hydrochloride. The study has been performed with and without addition of the copper (II) ions which are main catalysts in natural redox processes. It has been found that the photodegradation rate of oxytetracycline hydrochloride for the model system with addition of Cu2+ is lower than for the system without addition of Cu2+. Moreover, there exists a qualitative difference between transformational products formed with and without addition of Cu2+. It is obvious that the formation of Cu-antibiotic complexes causes these differences in the rates and products. Obtained results emphasize the importance of identifying the transformation products and the degradation rates of PPCPs in the presence of natural transition ions (Cu2+, Fe3+, Mn4+) and other cations (Ca2+, Mg2+), which can form complexes with PPCPs, in order to obtain results closer to the real environmental conditions.Item COMPOZIŢIA CHIMICĂ ŞI STAREA REDOX A APELOR NISTRULUI MEDIAL(2008) Gladchi, Viorica; Goreaceva, Nelli; Duca, Gheorghe; Bunduchi, Elena; Borodaev, Ruslan; Mardari, Igor; Romanciuc, LidiaThe result of construction of a hydrochemical system in the section line of the Dniester River at Novodniestrovsk was the achievement of practically total control of the river flow in the Moldovan part. At the same time, this system controls not only the seasonal variation of the level of the river but also forms a new hydrological and hydrochemical regime of the river as a result of the controlled discharge of water through the Novosdniestrovsk barrage. The level of impact of this process on the quality of waters was the main objective of current research. With this purpose during the years 2005-2006 there were performed investigations in the segment of the River starting with buffer reservoir (200 m below the barrage) at Naslavcea and ending with c. Dubasari (100 m below the Dubasari barrage). Water samples were collected in 6 different section lines. The parameters measured included: water temperature, pH, Eh, rH, hydrogen peroxide content, OH radicals content, dissolved oxygen, total amounts of iron, copper, soluble forms of nitrogen compounds, COD, BOD5 and others. A special attention was drawn to the analysis of the redox state of waters, the content of OH radicals and other parameters that were affected by man-made systems or activities. In the frames of the project 8 expeditions were carried out.