Facultatea de Chimie şi Tehnologie Chimică / Faculty of Chemistry and Chemical Technology
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Item REMOVAL OF DIRECT DYES FROM TEXTILE WASTEWATER BY MEANS OF COMBINED METHODS(2009) Matveevici, Vera; Duca, Gheorghe; Gonța, Maria; Iambarțev, Viorica; Mocanu, LiliaItem 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 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 CRISTOFOR SIMIONESCU(2007) Duca, Gheorghe; Vlad, Pavel; Gulea, Aurelian; Turtă, Constantin; Batîr, Dumitru; Lupașcu, Tudor; Revenco, MihailItem THE FORECAST AND THE STRATEGY OF CHEMISTRY DEVELOPMENT(2006) Duca, Gheorghe; Gulea, AurelianItem 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.Item COORDINATION PECULIARITIES OF THE SALICYLALDEHYDE S-METHYLISOTHIOSEMICARBAZONE IN THE PALLADIUM COMPLEXES(Academia de Ştiinţe a Moldovei, 2006) Revenco, Mihail; Bourosh, Pavlina; Duca, Gheorghe; Simonov, Yurii; Bulmaga, Petru; Jora, Elena; Gdaniec, Maria; Ketrush, PetruTwo coordination modes of salicylaldehyde S-methylthiosemicarbazone (Me-S-HSATSC-NH2) have been observed in the palladium complexes with this ligand. The interaction between Me-S-HSATSC-NH2 and tetrachloropalladate gives rise to the formation of a compound of the composition Pd(Me-S-SATSC-NH2)Cl which one has a planar structure. The organic ligand behaves as a monodeprotonated acid coordinated by O,N,S donor atoms set. This is the only case when the thioalkylated thiosemicarbazone uses the sulfur atom for coordination. The forth position in the coordination polyhedron of the complex is occupied by the chloride ion.figureMolecular structure of [Pd(Me-S-SATSC-NH2)Cl] and [Pd(Me-S-SATSC-N-NO)NO2]When the solution of K2[Pd(NO2)4] was treated with Me-S-HSATSC-NH2, the organic reagent undergoes a more dramatic chemical transformation carrying out to the formation of a new derivative of thiosemicarbazide – nitrozothioamide Me-S-SATSC-N-NO. The newly synthesized organic reagent is a monodeprotonated acid bound via O,N,N donor set, while the alkylated sulfur atom is uncoordinated. The forth site is occupied by NO2-ion coordinated by nitrogen atom (see fig.). The possible causes, driving the system to the formation of nitrosothioamide, and the impact of the anion on the coordination mode of the organic ligand will be discussed.Item ELABORAREA, CONFECŢIONAREA ŞI TESTAREA NEUTRALIZATORULUI DE GAZE DE EŞAPAMENT DIN BLOCURI MONOLITE ÎN BAZĂ DE CERAMICĂ DE TIP FAGURE(CEP USM, 2009) Crăciun, Alexandru; Ene, Vladimir; Duca, GheorgheThe work is dedicated to the identification of solutions for reduction of discharge into the atmosphere of harmful substances contained in exhaust gases from cars by means of application of neutralization in monolith blocks of cell ceramics.The works of this type have been carried out in Republic of Moldova for the first time.