WATER AND WATER PURIFICATION TECHNOLOGIES. SCIENTIFIC AND TECHNICAL NEWS

THE WAR IMPACT ON UKRAINE'S MARINE ENVIRONMENT

Svitlana Kyrii, Marta Litynska, Anna Misevych — Mon, 24 Jun 2024 00:00:00 +0300

The article is devoted to an overview of the impact of hostilities on Ukraine's marine environment. Marine ecosystems are highly vulnerable to anthropogenic factors, especially to pollution caused by hostilities, which leads to serious environmental, economic and social consequences. Ukraine, which has significant marine resources, faces the need to assess environmental risks and develop strategies to minimise them. Given the importance of marine areas for fisheries, tourism, transport and ecosystem services, a detailed study of the impact of military operations on the marine environment is crucial. Such a review will allow for the development of effective mechanisms to protect the marine environment, facilitate ecosystem restoration, and help reduce the negative impact on the economies of coastal regions. In this regard, studying the impact of military operations on the marine environment is essential for the future environmental security of Ukraine and the sustainability of its marine resources. The study aims to determine the impact of military operations on Ukraine's marine environment. It has been established that the extremely negative impact of military operations on the Black and Azov Seas is caused by the sinking of military equipment (ships, submarines, aircraft, unmanned aerial vehicles, etc.), which begins to corrode, releasing heavy metals (lead, copper, cadmium and mercury) into the water, as well as fuel materials containing oil and its derivatives. Oil forms a film on the sea surface, which harm photosynthetic organisms, disrupts gas exchange in the water, and can lead to mass mortality of fish and other aquatic organisms. This leads to the pollution of the aquatic environment, which can accumulate in marine life and affect the entire ecosystem. Another important example of the impact of military operations is the presence of explosive remnants in the Black and Azov Seas, such as mines and shells, which can remain dangerous for decades after the end of hostilities, posing threats to marine biota and human health. Military action will, therefore, have far-reaching consequences for the Black and Azov Seas, creating complex environmental, economic and social problems.

PROSPECTS FOR USING 3D PRINTING TO FORM CERAMIC MEMBRANES: A BRIEF REVIEW

Anastasiia Diachenko, Khrystyna Hutsul, Tetiana Dontsova — Mon, 24 Jun 2024 00:00:00 +0300

The article presents a discussion of the potential applications of 3D printing in the formation of ceramic membranes. In recent years, additive technologies for ceramic materials have become a prominent area of research, suggesting that they can be effectively employed to design and produce hierarchical porous ceramic structures, combining flexible design and advanced approaches to their formation. The objective of this paper is to analyse the potential of additive technologies for the production of ceramic membranes, identify the most promising technologies, and provide a comprehensive evaluation of their achievements, challenges, and limitations. The present study considers seven principal additive manufacturing processes, which are based on the utilization of diverse 3D printing technologies. It is demonstrated that the most promising technologies for the manufacture of ceramic membranes are currently Vat Photopolymerisation, which enables the production of products with complex geometry and high accuracy, and those that utilize Powder Bed Fusion processes, which ensures the mechanical strength and density of ceramic products. The article presents an analysis of the printing parameters of Stereolithography, Liquid Crystal Display and Selective Laser Sintering technologies, and their potential for the production of ceramic products in general and membranes in particular. The problems and challenges of creating ceramic membranes by 3D printing, such as optimization of the composition of ceramic suspensions and post-processing of products, are noted. Possible ways to solve them are discussed, including the improvement of printing materials and technological processes. The prospects for the use of the obtained ceramic membranes in various industries are also considered. The directions of further research aimed at improving additive technologies for printing ceramic membranes and expanding their application in industry are identified.

POTENTIAL APPLICATIONS OF TIO2/NATURAL ZEOLITE COMPOSITES FOR DYE REMOVAL

Viktor Kurylenko, Tetiana Dontsova — Mon, 24 Jun 2024 00:00:00 +0300

Water pollution by organic dyes is a critical environmental issue that requires innovative and effective solutions. Photocatalytic materials based on titanium dioxide (TiO₂) can effectively degrade these pollutants; however, their use in suspension form has several drawbacks, such as the difficulty of separation and limited reusability. To overcome these limitations, the use of composites is promising, as they simplify the separation of TiO₂ after the reaction. The aim of this study is to modify natural Ukrainian zeolite and its acid-activated form with TiO₂nanoparticles and to determine their photocatalytic activity towards anionic dyes. TiO₂/zeolite composites were synthesized by depositing titanium (IV) oxide nanoparticles onto natural zeolite and its acid-activated form, followed by thermal treatment at 500 °C. Characterization of the composites showed that the acid-activated composite achieved a specific surface area of 173.8 m²/g compared to 34.5 m²/g for the natural composite. The photocatalytic activity of the composites was evaluated by the degradation of the anionic dye Congo Red (10 mg/L) under ultraviolet irradiation. The results showed that the acid-activated zeolite modified with TiO₂ nanoparticles achieved a Congo Red degradation efficiency of 65.6% after 30 minutes of ultraviolet exposure, which is 12% higher compared to the natural zeolite modified with TiO₂ under the same conditions. The adsorption efficiency for Congo Red was 33.8%. This indicates that the composite not only facilitates the photocatalytic degradation of the dye but also contributes to its adsorption, enhancing the overall removal efficiency. Thus, the use of inexpensive natural zeolite as a TiO₂ carrier, especially in its acid-activated form, not only simplifies the subsequent separation of the photocatalyst from the purified water but also maintains the photocatalytic efficiency in degrading anionic dyes. The enhanced surface properties and structural characteristics of the acid-activated composite make it highly effective for practical applications. This makes such composites promising candidates for application in industrial wastewater treatment systems, where economic feasibility, operational simplicity, and environmental safety are primary criteria.

FEATURES OF THE OPERATION OF COLD AND HOT WATER SUPPLY SYSTEMS REGARDING THE CORROSION ACTIVITY OF ZINC-PLATED PIPES IN WATER SUPPLY

Anatoliy Klymenko, Svitlana Kovalenko, Yurii Kovalenko — Mon, 24 Jun 2024 00:00:00 +0300

The exploitation of zinc-plated household water supply systems is associated with the problem of the development of local corrosion processes on the inner surface of steel pipes. Research on this topic is quite relevant, as evidenced by the analysis of articles on short-term use of zinc-plated pipes in water supply systems. The work presents aspects of consideration of the influence of water treatment, operational parameters and the presence of zinc coating on the performance of the system from the point of view of the development of local corrosion processes. The need for control by comparing water quality indicators "before and/or after water treatment" and "water in the system", was highlighted. This makes it possible to detect an aggressive corrosive environment already at the beginning based on the indicators of dissolved oxygen, free carbon dioxide and the index of equilibrium saturation of water with calcium carbonate and to establish the state of the inner wall ("active / passive") based on the presence of an increased concentration of iron, oxygen, and zinc ions. It was established that the presence of molecular oxygen dissolved in tap water in the hot water supply system in the temperature range of 60...70 ºC leads to the loss of protective properties by zinc due to the formation of a surface passive film of the ZnO, which leads to a shift in the corrosion potential of zinc to a more positive region, compared to the protective potential of iron, values. Cold water supply systems are characterized by the electrochemical nature of corrosion processes with oxygen cathodic depolarization. On top of that, the inadmissibility of direct contact of zinc-plated pipes with fittings elements and shut-off valves that made of brass, bronze and copper due to the destruction of the metal wall of the pipes due to the contact corrosion, has been proven - the potential difference of these galvanic elements is from 0.570 to 0.854 V.

Key words: water supply system, tap water, water quality, corrosion, zinc-plated pipes, electrochemical research

TECHNOLOGIES AND HEAT EXCHANGE EQUIPMENT FOR TREATMENT AND UTILIZATION OF WASTEWATER FROM THERMAL POWER PLANTS

Mon, 24 Jun 2024 00:00:00 +0300

The article considers the problems of hydrosphere pollution in Ukraine, in particular, those related to the activities of thermal power plants. The main sources of discharges that arise during their operation are described, including wastewater from cooling systems, exhaust gas desulfurization systems, as well as water contaminated with petroleum products. The classification of wastewater, its features and consequences for the ecosystem emphasize the relevance of compliance with discharge standards and, depending on their types, allow you to choose a method for their purification and disposal. The article describes in detail the processes of purification of polluted waters with an emphasis on the use of unique methods and equipment, such as rotary aeration and oxidation plants, which increase the efficiency of purification by using the method of discrete-pulse energy input. The authors propose modern technologies for emulsifying watered liquid hydrocarbons, which provides the possibility of utilizing wastewater from thermal power plants contaminated with petroleum products. The analysis showed that the design of the rotor-pulsation apparatus unit implements intensive homogenization and emulsification of the treated system. The processes of combustion of water-fuel emulsions are also considered, which allows reducing emissions of pollutants. The results of the study indicate the possibility of significantly reducing the negative impact on the environment due to effective wastewater treatment to maximum allowable concentrations of harmful substances in water bodies. The conducted studies allow making the right choice of treatment or disposal technology, their treatment mode depending on the type of wastewater, which will ensure compliance with environmental standards to ensure the purity of water resources of Ukraine.