Marysyk S. Justification of technological and design parameters for the application of sorption materials in water purification from heavy metal ions and radionuclides

The dissertation represents a completed scientific study addressing the urgent task of scientifically substantiating the use of effective sorbent materials and the design of a settler-adsorber for removing modern pollutants from water, including heavy metal ions and radionuclides. Relevance: Effluent waters, such as those from nuclear power plant heat exchangers, enter surface sources containing radionuclides; mine and quarry waters pollute underground and surface sources; and military actions result in the introduction of heavy metal ions and chemical warfare agents into water sources. Objective: To investigate the properties and justify the application of modern sorbent materials for the removal of heavy metal ions and radionuclides from water and to develop a structure for the effective adsorption and sedimentation of modern pollutants from water. Research tasks: To analyze promising sorbents for the removal of heavy metal ions and radionuclides from water; to conduct laboratory studies of the hydrodynamic characteristics of the selected sorbent materials; to develop a mathematical model of the processes of adsorption and sedimentation of pollutants from water; to develop the design and justify the parameters of a facility to ensure optimal conditions for the sedimentation of pollutants; and to conduct testing and implementation of the proposed facility in production. The relevance of the topic is presented, the use of sorbent materials for removing heavy metal ions and radionuclides is substantiated, and a solution for the design of a universal "settler-clarifier" structure is proposed to optimize the processes of adsorption and sedimentation of pollutants. The structure of pollutants is analyzed, and modern cleaning technologies for wastewater and natural waters are reviewed. The application of natural sorbents, which have significant adsorption capacity that can be developed through modification, is substantiated. The key advantages of these materials are as follows: natural sorbents are widely distributed in Ukraine; they are accessible and inexpensive materials; adsorption technologies using dispersed sorbents provide a high degree of purification; and used natural sorbents can be utilized in technologies for producing other products. The physico-mechanical properties of various sorbents are described, and the application of promising materials for the adsorption of heavy metal ions and radionuclides is justified. Data regarding the research object and the methodology of laboratory studies are provided. Experiments on hydraulic particle size were conducted using a model solution of prepared water and sorbents of bentonite, zeolite, and copper ferrocyanide, synthesized by mixing solutions of potassium ferrocyanide and copper sulfate. The optimal number of measurements of the multifactorial dependence was determined using the Box-Wilson method. The results of laboratory experiments to determine the hydraulic particle size of the studied sorbents, as well as the results of mathematical modeling of hydrodynamic processes in the universal structure, are highlighted. Empirical models of turbidity change in the process of settling sorbent colloids were obtained from laboratory studies, and a correlation analysis of possible connections in the sedimentation process of colloidal conglomerates was performed. The best results, both in terms of hydrodynamic and sorption properties, were shown by the copper ferrocyanide-bentonite mixture. The modeling of hydrodynamic processes was conducted in the virtual environment of Autodesk CFD, based on the finite element method. From the modeling results, patterns of flow velocity distribution in the settler-adsorber were obtained, based on which the parameters of the structure providing optimal conditions for adsorption and sedimentation of pollutants from water were determined. The proposed universal technological structure "settler-adsorber" allows for reduced energy consumption by using gravitational forces instead of electricity for mechanical mixers to carry out water purification processes from radionuclides and heavy metals. The risks of radioactive environmental contamination related to the transfer of treated liquid from one structure or equipment to another are also reduced, as all technological processes occur within a single structure.