Tverdokhlib M. Intensification of water purification processes from iron and manganese compounds.

Українська версія

Thesis for the degree of Candidate of Sciences (CSc)

State registration number

0419U005218

Applicant for

Specialization

  • 21.06.01 - Екологічна безпека

10-12-2019

Specialized Academic Board

Д 26.002.05

Publishing and Printing Institute of Igor Sikorsky Kyiv Polytechnic Institute

Essay

The dissertation is devoted to the development of the ecologically safe methods of the intensification of the water purification processes from iron and manganese compounds. The purification of the natural waters from the compounds of iron and manganese is one of the importance given the toxicity of these elements that can accumulate in the alive organisms, achieve the high concentrations and impose a negative impact on human health. Today, there are a number of typical technologies of disinfection and demagnetization of water, which are presented in the first part of the dissertation. Many works have also been published which describe the purification of water from iron and manganese by sorption, ion exchange, barometric methods, aeration and filtration, catalytic oxidation. However, most of the listed methods have significant disadvantages. In the first stage of the research, it was found that the degree of iron and manganese oxidation in the water environment depends on the time of contact of water with air and the reaction of the environment, as well as from the initial concentration of metal in water. In the study of the process of oxidation of manganese ions in aqueous medium, it was found that significant influence on the passage of the process has the pH of the medium and the administration of the solution. The oxidizing properties of the anion exchanger AB-17-8 modified by chlorine and manganese compounds in the process of water de-ironing were determined. A mixture of anion exchanger AB-17-8 in ClO2- form and cation exchanger KУ-2-8 in Na+ form has been shown to provide effective iron removal and water softening. It has been established that high efficiency of water purification from the iron ions can be achieved by filtering it through an anion exchange agent AB-17-8 in a mixed ClO2- and OH- form. At the same time, the efficiency of removal of iron from water due to the use of chloride anions increases with the increase in ion exchanger volume. Established, the effective removal of iron ions occurred depending on the dose of magnetite and contact time, as well as the initial concentration of iron ions in water. When using magnetite for demagnetization of water, a significantly higher efficiency of water purification from manganese was achieved by increasing the pH of the medium and by blowing air or stirring the solution. It was established that the use of catalytic filtration loading on the basis of ion exchange resin and magnetite significantly accelerates the process of purifying water from iron and manganese compounds. The optimal water filtering speeds at the pilot plant for disinfection have been determined. In the process of filtration, there was a decrease in the concentrations of residual iron in purified water over a long time cycle filter. It was established that at speeds of 1,5-4,5 m/hr there is a uniform accumulation of sediment in the thickness of the filter loading, which leads to the effective oxidation of iron ions and the elongation of the filter cycle. When exploring the removal of manganese compounds from water on a pilot plant, it was possible to achieve the complete removal of manganese ions, regardless of the form of cation. The research of the application of sodium hypochlorite as an oxidizer in the purification of the artesian water from the manganese ions has been carried out. In static conditions, it was determined that the degree of manganese with draw al affects both its initial concentration in water and the dose of sodium hypochlorite. In this case, the water purification from manganese ions is more effective with initial concentrations above 5 mg/dm3. On the basis of the obtained results the technological scheme of purification of artesian water from iron and manganese compounds is presented. The use of filter loading on the basis of ion exchange resin and magnetite as a catalytic filter is proposed, for the removal of iron ions, manganese and rigidity. The economic effect of the introduction of this technology is calculated.

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