Studies of oxidative and reductive processes in multicomponent systems of natural waters

Abstract

The important issue in the control of water quality is to determine the influence of the state of elements with variable valence on the redox potential, which is a quantitative measure of the ability of water to the oxidation or reduction. In this work the influence of hydrocarbonate ions HOC-3 on the redox potential of the model water multicomponent systems that simulate the chemical composition of natural waters has been investigated. For this purpose, thе H2O-Fe2+-HCO-3-O2, H2O-Fe3+/Fe2+-O2 systems have been studied The choice of objects for the study is due to a variety of forms and concentrations of iron found in natural waters, which creates the need to develop methods, technological schemes and facilities for iron removal.It was found that the oxidation process in the H2O-Fe2+-HCO-3-O2  system was affected by the content of  HCO-3 ions. For small Fe2+ concentrations the influence of HCO-3  ions was the larger, the higher was their concentration, as evidenced by the Eh change in time. High Fe2+ concentrations has slowed the process of oxidation, which was probably due to the formation of hydrox complexes of iron (III). This was also indicated by the change in solution pH at high  HCO-3  concentrations. For the H2O-Fe3+/Fe2+-O2  system it was found that at low Fetotalconcentrations, the oxidation was accompanied by Eh  increase. At high Fetotal concentrations, a decrease of the redox potential, was observed which can be explained by the lack in a system of the oxidizer ─ the oxygen dissolved in water