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CNAA / Theses / 2010 / May /

Redox-Catalytic transformations of hydroquinone and glyoxalic acid in aquatic environments


Author: Bunduchi Elena
Degree:doctor of chemistry
Speciality: 11.00.11 - Environmental Protection and Rational Utilization of Natural Resources
Year:2010
Scientific adviser: Gheorghe Duca
doctor habilitat, professor, Moldova State University
Institution: Moldova State University
Scientific council: DH 30-11.00.11-25.12.03
Moldova State University

Status

The thesis was presented on the 14 May, 2010
Approved by NCAA on the 5 July, 2010

Abstract

Adobe PDF document0.60 Mb / in romanian

Keywords

oxidant, reducer, catalyst, hydroquinone, glyoxalic acid, self-purification process, redox state, hydrogen peroxide, capacity of inhibition, kinetic indicator

Summary

The structure of thesis: Introduction, 5 chapters, Conclusions and Recommendations, Bibliography of 120 titles, 30 figures, 9 tables, the List of abbreviations and 106 pages.

The number of publications: 17, 8 article and 9 thesis.

The purpose and objectives of the paper: The thesis relates to the field of environment protection, and, especially, to the protection of natural waters. The scientific results presented in current work envisage the process of transformation of hydroquinone and glyoxalic acid in natural waters that represent a redox-catalytic system, and allow the evaluation of the contribution of these processes to self-purification, formation of the composition and quality of natural waters, that serves as living environment for hydro-biota.

The novelty and scientific originality: The results obtained, confirm that diminishing of the content of H2O2 and OH radical causes the decrease of self-purification capacity of natural waters, inducing unfavorable conditions hidro-biota. It has been proved that the processes of peroxydase oxidation of substrates under the influence of copper (II) ions catalysts the OH radicals a formed, while in the processes where iron (III) ions are used their formation does not occur. In the presence of hydroquinone the self-purification capacity of natural waters is decreasing. On the contrary, the presences of glyoxalic acid in natural water environments contribute to intensification of the processes self-purification through radicals. The kinetic indicators were applied for the evaluation of self-purification capacity of waters from Nistru and Prut rivers.

The theoretical importance and applied value of the work: The investigations presented in current work confirmed the efficiency of application of the kinetic principle for the description of self-purification processes in natural waters. The role of particles from biogeochemical cycle of O2 and transition metals in the processes of self-purification has been proved. The obtained regularities can be applied for the explanation of redox processes of self-purification occurring with participation of hydroquinone and glyoxalic acid derivatives.