Facultatea de Chimie şi Tehnologie Chimică / Faculty of Chemistry and Chemical Technology
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Item ROLUL COBALAMINEI ÎN PROCESELE DE AUTOPURIFICARE RADICALICĂ ÎN MEDIUL ACVATIC(CEP USM, 2024) Lis, Angela; Gladchi, Viorica; Blonschi, Vladislav; Cisteacov, Maxim; Bunduchi, ElenaThe main purpose of this research is to study the role of Cyanocobalamin (CNCbl) in aquatic ecosystems. The spectrophotometric method was used to determine the inhibition capacity and the concentration of OH radicals using PNDMA traps. As a result, it was found that, on the one hand, CNCbl is a reducing substance and leads to the consumption of oxidative equivalents, resulting in its oxidation. High inhibition capacity values and low OH radical values confirmed this. On the other hand, under irradiation, CNCbl can also act as a sensitizer. It actively absorbs photons in the UV and visible range, transitions to an excited state, and then transfers the electronic excitation energy to dissolved oxygen in water, forming active species such as singlet oxygen and superoxide radical anion. In the presence of protons, the superoxide radical anion is reduced to hydrogen peroxide, which generates OH radicals upon irradiation. From the obtained results, it can be seen that under the conditions of natural aquatic systems, CNCbl will not disturb the processes of radical self-purification.Item STABILIREA IMPACTULUI POLUĂRII CU VITAMINA B6 ASUPRA CAPACITĂȚII DE AUTOPURIFICARE A SISTEMELOR ACVATICE NATURALE (LACURI)(CEP USM, 2024) Bunduchi, Elena; Gladchi, Viorica; Cisteacov, Maxim; Lis, Angela; Blonschi, Vladislav; Duca, GheorgheIn the framework of this research, it was aimed to establish which concentrations of vitamin B6 can be considered triggers of the pollution phenomenon in natural aquatic systems of the lentic type, such as the Danceni and Ghidighici lakes. The modeling was done on microcosm type systems. The pollution and auopurification processes were monitored according to the quality indicators for natural waters: pH, permanganateometric oxidizability (CCOMn), degree of saturation with dissolved oxygen (OD, mgO2/L) and inhibition capacity (Σki[Si], s-1). Research shows that natural waters can become vulnerable to vitamin B6 pollution in concentrations of the order of ≤ 0.5·10-4 M, because self-purification processes fail to eliminate the pollution caused by these concentrations, only slightly attenuating it. The consumption of active forms of oxygen, OH radicals, important particles of the chemical self-purification process of natural waters, highlight even more the negative impact of the pollution of aquatic systems with vitamin B6.Item EVALUAREA IMPACTULUI COMPUŞILOR TIOLICI ASUPRA STĂRII REDOX A APELOR FLUVIULUI NISTRU ÎN PERIOADA ANILOR 2015-2019(CEP USM, 2021) Blonschi, Vladislav; Cisteacov, Maxim; Gladchi, Viorica; Bunduchi, ElenaItem MONITORINGUL CONŢINUTULUI SUBSTANŢELOR TIOLICE ÎN APELE RÂURILOR RĂUT ŞI ICHEL ÎN PERIOADA ANILOR 2015-2020(CEP USM, 2021) Cisteacov, Maxim; Blonschi, Vladislav; Gladchi, Viorica