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Документ Відкритий доступ Towards models complexity in water usage and treatment optimisation problems(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Shakhnovsky, A.The paper addresses water recycling in process industry, inter alia, the issues of mathematical models’ complexity problem in the “process integration”-based structural optimization of sustainable water usage and treatment networks. The nature of addressing structural optimization problems requires iteratively querying individual process models, which are incorporated as objective functions and constraints within the optimization model, throughout the process of finding a solution, therefore the goal was to explore the intricacy of mentioned models. Within the framework of the research, the impact of complexity of water network constituent parts models on the optimization performance was investigated by Monte Carlo method for one step of the optimization procedure, as well as for the optimization procedure as a whole. Units’ models in form of algebraic equations (for direct equation calculation case), algebraic equations (for root search), ordinary differential equations (for Cauchy initial value problem with a case of two differential equations), ordinary differential equations (for boundary value problem), and partial differential equations (for two spatial variables) were examined with an analysis of their applicability for optimization purposes. The justification for employing both deterministic "counter-current mass transfer" models and statistical polynomial "input-output" steady-state algebraic models were established for addressing the specific problems under investigation. As the case study, special polynomial model was constructed based on the experimental design / response surface methodology and the dynamics simulation results on adsorption wastewater treatment within the packed bed column filled with activated carbon. Central composite rotatable design was formulated and subsequently executed using computational experimentation methods for the parametric identification of a nonlinear polynomial model. The evaluation confirmed that the constructed model exhibits satisfactory predictive accuracy.Документ Відкритий доступ Shared automatic drinking water treatment and dispensing systems and methods of their optimization(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Mudryk, R.; Mitchenko, T.Access to clean and safe drinking water is a fundamental human right. However, in many parts of the world, water scarcity and contamination pose significant challenges. To address these issues, shared automatic drinking water treatment and dispensing systems have emerged as innovative solutions. The article is devoted to the problem of access to safe, physiologically complete drinking water in collective systems of water preparation and sale, namely in water vending machines. Since such machines are a relatively new solution, the search for rational ways of adapting existing technologies is relevant and necessary for their widespread implementation. The article discusses the peculiarities of preparation and sale of water in the network of existing vending machines. It was established that automatic machines are autonomous multifunctional systems, the effectiveness of which depends on the balanced operation of all elements. Formulated requirements for the operation of automatic machines in autonomous conditions, namely, regarding water quality, automatic machine productivity, and the duration of its operation without operator intervention. A comparison of the requirements with operational data showed a discrepancy in water quality (in terms of hardness, pH, dry residue), productivity (10 times higher than required), duration of operation without an operator (4 times shorter than specified in the requirements). Factors influencing the operation of vending machines are formulated, namely: water preparation technology, number of stages, resource of filter elements, volume of water for own needs, combination of payment methods, time or volume logic of service. To achieve the proposed requirements, solutions have been developed, the effectiveness of which will be investigated in the course of further work. It was noted that a mandatory condition for the successful solution of the tasks set is digital control of the operation of the machine.Документ Відкритий доступ Rational conditions of producing the activated carbon with well-developed nanoporous structure for the treatment of natural and waste waters(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Klymenko, N.; Savchyna, L.; Kosogina, I.; Vrubel, T.Rational conditions for the activation of coal of a high stage of metamorphism (anthracite) have been determined, which allow the development of a nanoporous structure. Obtained activate carbon with nanoporous structure can be use for the treatment of natural and waste waters have been carried out. The structurally sorptive characteristics and granulometric size composition of obtained samples were determined. It was established that in order to obtain a sorbent with specified properties, it is necessary to introduce oxygen into the reacting mixture at the second stage of anthracite activation and control the activation time. The activation in the first stage was carried out with steam at a temperature of 750–800 °C, and in the second stage – with steam in the presence of air oxygen at 280–300 °C. The rational content of oxygen in the activating mixture is in the range of 2.7–4.4 %, while the specific surface area of activated carbon increases, which corresponds to nano-sized pores and, accordingly, the volume of the adsorption space of coal. The process led to the development of mesoporosity ~ 0.2–0.3 cm3 /g, after which the microporous sample of activated carbon was impregnated with a surfactant solution. Thus, the rational conditions of activation are the duration of the process of 1.5 hours in the presence of 4.4 % oxygen in the activating mixture. It is shown that the largest values of the total specific surface area and the specific surface area of mesopores are achieved when using ionic surfactants with alkyl chain length n = 10–16 as modifiers. In particular, the use of sodium dodecyl sulfate СН3(СН2)11SO3Na as a modifier allows to obtain the largest value of the total surface Stot 1030 m2 /g and the surface of mesopores Smе 334 m2 /g. It was established that the activation of modified samples of activated carbon leads to a decrease in the size of granules.The content of fractions with a size of 1.0–2.0 mm and 0.5–1.0 mm is 80–85 %, which are rational for use for water purification from organic compounds.Документ Відкритий доступ Decomposition mechanism and dissociation constants of bicarbonate ions(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Kontsevoi, S.Using carbonic acid to explain pH changes in aqueous solutions is invalid due to its undetectability under normal temperature and pressure conditions. Instead, two reversible reactions involving the decomposition of HCO3 - ions into OH- and CO2 or H+ and CO3 2- should be employed. The second reaction (H-mechanism) is well known as the basis for the second dissociation constant of “carbonic acid”. For the first reaction (OH-mechanism), the formula has been derived from the first imaginary constant of the same acid. That is, the researchers experimentally determined the proposed constant based on the results of pH value, CO2 and HCO3 - concentrations, but calculated the imaginary constant from these values. The pH increase observed following filtration on the cationic resin in Na+ form is attributed to the weakened HCO3 - decomposition via the H-mechanism, resulting in decreased H+ and CO3 2- concentrations. A significant decrease in Ca2+ concentration (from 5.0 to 0.05 mmol/dm3 ) is the main reason for the observed phenomenon, as it leads to a decrease in the driving force of calcium carbonate formation. The mechanism of bicarbonate ions decomposition based on two reactions has been confirmed experimentally. An increase in the pH of the mixture of CaCl2 and NaHCO3 solutions (both with the same pH and concentration) indicates the Hmechanism, while a decrease in the pH indicates the OH-mechanism decomposition of bicarbonate ions. The pH value at which the pH does not change indicates a change in the decomposition mechanism. The change in the HCO3 - dissociation mechanism depends on hardness and alkalinity, and the pH of this change decreases from softened water (pH 8.30) to seawater (pH 7.5).Документ Відкритий доступ Materials and methods for ceramic membrane synthesis. Short review(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Kyrii, S.This article briefly overviews the main types of raw materials used to synthesise ceramic membranes. Traditional materials such as aluminium oxide, silicon dioxide, titanium dioxide, zirconium dioxide, zeolites, and cost-effective materials like various clays and industrial waste are highlighted. Modern methods for producing high-performance ceramic membranes are discussed, including slip casting, tape casting, pressing, extrusion, solid state method etc. The general scheme for preparing a selective layer on a ceramic membrane using various methods for synthesising it is also examined. Furthermore, the cost of commercial ceramic membranes and influencing factors are analysed. Based on contemporary literature, ceramic membranes exhibit distinct advantages over polymer membranes with their potential for application under high temperature, high pressure, and aggressive environments. Additionally, their energy efficiency, compactness, and versatility make them a viable alternative for water purification, replacing more expensive methods like coagulation and adsorption. Ceramic membranes have become a competitive alternative to polymer membranes, showcasing unique material properties and excellent characteristics. Using cost-effective materials for ceramic membrane fabrication allows for utilisation in economically sensitive sectors. Such membranes demonstrate excellent mechanical properties and high permeability, while inexpensive materials can reduce costs. Current scientific research and developments focus on utilising various clays and waste materials to produce ceramic membranes, aiming to create new generations of ceramic membranes for environmentally friendly applications.Документ Відкритий доступ The effect of the type and content of carbonates on the characteristics of porosity of ceramic membranes(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Yanushevska, O.The main issue considered in the work is the creation of a matrix for ceramic membranes, which would be distinguished by low cost and high porosity. In order to reduce the cost of ceramic membranes, a widespread approach was chosen, which is powerfully used by many researchers, namely the use of natural minerals - kaolin and saponite - as the main components of the matrix. Carbonates were used as pore generating agents to achieve the required porosity value. Three series of ceramic membranes (CM) differing in chemical composition were synthesized in the work: KP1, KP2, and KP3 series. The main composition of CM includes: kaolin, saponite, sodium silicate and carbonates. The effect of the type and amount of carbonates (CaCO3, NH4HCO3, (NH4)2CO3) as pore generating agents on the formation of the porous structure of the samples was studied. The type and content of carbonates varied in different samples from 8 wt% up to 40 wt%. The dry pressing method using pressure equivalent to 8 tons and 15 tons was used to form ceramic membranes. The main parameters by which the properties of ceramic membranes were evaluated: water absorption, total and open porosity. Standard methods were used to determine these parameters for synthesized samples. The chemical composition of the dry mixture of the ceramic membrane, for which the porosity is the maximum in the series of manufactured samples, was established. It was established that the addition of calcium carbonate components to the dry mixture increases the porosity of ceramic membranes and water absorption. The chemical composition of a ceramic membrane sample with the best indicators of total and open porosity in the KP2 series is given. The chemical and phase composition of samples of the KP2 series, as well as their structural and adsorption characteristics, were investigated by X-ray fluorescence and diffraction methods of analysis and low-temperature nitrogen adsorption-desorption. The effect of the addition of silicon carbide on the characteristics of the porosity of the samples was determined.Документ Відкритий доступ Use of textured surfaces for condensation of water vapour and mist(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Myronyuk, Oleksiy; Che LiProducing purified water from air moisture is feasible even in arid areas where humidity is intermittent. This method relies on a condenser, usually cooler than the surroundings, where water condenses. Many studies use materials with diverse hydrophobicity, making it hard to pinpoint surface effects on condensation. Thus, comparing hydrophobic and hydrophilic surfaces with identical textures is crucial. The aim of this work is to determine the effect of gyrophobic metal surfaces on the processes of water collection from steam. Experiments in this work were conducted in a close chamber in the environment of water fog produced by the fog machine at the room temperature. It was shown that hydrophilic surfaces enhance water vapor condensation efficiency by up to 38% compared to hydrophobic ones. In this work, the femtosecond laser treatment was used to produce channel-shaped textures with a truncated trapezoidal cross-section, measuring 15 µm at the upper base, 45 µm at the lower base, and 22 µm in height. These textures were further extended by the development of aluminum oxide crystal inlays, ranging from 30-60 nm, due to metal oxidation from the laser's high-temperature interaction. Extended exposure to these textures in room environment naturally increases their water repellency. Contact angles can reach 148°, nearing the 154° efficiency achieved with stearic acid treatment. However, heating to 380 °C eliminates the hydrophobic layers, resulting in complete hydrophilisation. Textured hydrophilic surfaces prove most effective for condensate collection, outperforming hydrophobic surfaces by up to 28%. Additionally, microtexture orientation matters: a vertical orientation boosts condensate collection by 34% compared to horizontal orientation. The results may be useful in the development of water harvesting equipment for naturally dry regions, or place where extensive water purification is required.Документ Відкритий доступ Digitalization of water vending machines(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Mudryk, Rostyslav; Orestov, YevhenVending, the sale of goods and services through automated systems, has gained worldwide popularity as a convenient and low-maintenance method of commerce or service delivery. With its wide range of applications, vending can be used in almost all areas of commercial and social life. This article is dedicated to studying the impact of digitalization on the operation of water vending machines. These machines represent a modern way of obtaining safe and physiologically complete drinking water. Their advantage lies in autonomous operation without the constant presence of servicing personnel. This is achieved by replacing filters and maintenance tasks carried out on a time-based logic basis. However, time-based logic does not account for actual volumes of purified water, leading to over expenditure on servicing some machines and untimely maintenance, resulting in a deterioration of water quality for others. This study investigates the impact of digitalization on optimizing service costs and the cost price of water purification. It is shown that through digitalization, the maintenance logic was changed to volume-based, resulting in reduced expenses on replacement filters (51%), servicing (13%), and collection (17%). Collectively, these factors reduced the cost of water by 20%. The decrease in cost enhances the profitability of the vending machine network. With a fixed water price, this is the only way to increase profitability and attract investors, consequently popularizing water vending machines. Subsequent research will focus on seeking alternative filters, materials, and water preparation technologies to achieve even greater machine autonomy. By assessing the established impact of digitalization on water vending machine operations, a predictive cost of water is calculated, assuming compliance with all operational requirements. The predicted cost reduction amounts to 39%, providing economic justification for future research endeavors.Документ Відкритий доступ Photocatalytic activity of ZnO/TiO2 composites in circulating conditions(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Hutsul, K. R.; Ivanenko, I. M.The development of new efficient photocatalysts is an important task for solving problems related to the purification of water and air from organic pollution. Composite materials based on ZnO and TiO2 exhibit high photocatalytic activity, which makes them promising for this application. In this work, we present the synthesis and study of the photocatalytic activity of ZnO/TiO2 composites obtained by the method of intermediate hydroxide deposition. The synthesis was carried out on the surface of Evonik P25 TiO2 with three different mass ratios of ZnO to TiO2: 1:3, 1:1, and 3:1. The resulting composites were studied by X-ray diffraction (XRD), spectroscopy to determine the optical band gap, and subjected to photocatalytic decomposition under circulating conditions. It was confirmed by XRD that ZnO crystallizes in the wurtzite phase of hexagonal syngony, and TiO2 is contained in the form of two modifications: anatase and rutile. The effect of the mass ratio of ZnO to TiO2 on the optical band gap has been studied. The optical band gap of ZnO/TiO2 composites was determined using the Kubelka-Munk algorithm. For the composites (1)ZnO/TiO2 and (3)ZnO/TiO2, the bandgap was 3.22 eV, and the lowest value (2.99 eV) was obtained for the composite with an equal ratio of ZnO to TiO2 - (2)ZnO/TiO2. The photocatalytic activity of ZnO/TiO2 composites was studied under circulating conditions with congo red dye in the presence of four different composite weights: 0.2, 0.4, 0.6, and 2 g. The maximum efficiency of photocatalytic decomposition of the dye was observed for the composite with an equal ratio of ZnO to TiO2 at a dosage of 2 g of the composite per 0.075 g of dye. The synthesized ZnO/TiO2 composites exhibit high photocatalytic activity, which makes them promising materials for water and air purification from organic pollution. The optimum mass ratio of ZnO to TiO2 for the photocatalytic decomposition of congo red dye is 1:1.Документ Відкритий доступ Adsorption removal of Cu (II) using Ni-modified silica gel(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Yu, Junjie; Bondarieva, Antonina; Tobilko, Viktoriia; Pavlenko, VolodymyrThe contamination of surface and groundwater with heavy metals represents a significant threat to environmental safety and the health of living organisms. Consequently, the development of new technologies and the improvement of existing ones to clean water bodies from toxicants of various kinds represents an important task. One of the factors influencing the choice of treatment method is the concentration of the pollutant. It is advisable to use adsorption methods for the post treatment of water environmental to the levels of maximum permissible concentrations. In the context of the implementation of adsorption methods, the selection of sorbents that combine high efficiency and low cost with ease of preparation represents an important factor. The aim of this work is to produce a sorbent based on commercial silica gel and nickel oxide. For its synthesis, the thermolysis method was chosen. A series of materials with varying mass ratios of NiO to SiO2 was produced: 1:1 and 0.5:1. The presence of crystalline nickel oxide on the amorphous surface of SiO2 was confirmed by X-ray diffraction analysis. The main parameters of the porous structure were determined by the method of low-temperature nitrogen adsorption/desorption. With an increase in the amount of the deposited oxide layer, the specific surface area and pore volume of the obtained samples decrease by 1.5-2.5 times compared to the original SiO2. At the same time, the general character of the mesoporous structure is preserved. The optimal conditions for the removal of Cu (II) ions by nickelcontaining composites based on silica gel (pH - 5.5; sorption time - 1 hour) were investigated. The adsorption kinetics is adequately described by a pseudo-second-order model, which indicates a high affinity of copper for the surface of such samples. It was demonstrated that the modification of the SiO2 surface with nickel oxide results in an enhancement of the sorption capacity of materials with respect to Cu (II) ions. The maximum value of copper sorption on the synthesised samples is 10 times higher than on the original SiO2.Документ Відкритий доступ Structure formation of iron-containing dispersions of organomontmorylonite(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Zhdaniuk, N. V.The aim of the work is to study the processes of structure formation of organomontmorillonite in iron-containing dispersions by studying the rheological and colloid-chemical properties of such systems. To modify the surface of montmorillonite, a cationic surface-active substance, a quaternary ammonium salt, hexadecyltriammonium bromide, was used. With the help of X-ray diffraction analysis, we confirmed the penetration of molecules of surface-active substances into the interlayer space of the mineral and its increase to 1.86 nm during the modification mineral surfactant/ cation exchange capacity (S/CEC)=1. The analysis of the results of rheological studies showed that the changes in the characteristics of montmorillonite dispersions depending on the concentration of surfactants are extreme and reach a maximum (6.7 Pa) at the degree of modification of the mineral S/CEC=0.3. The high values of ultimate shear stress confirm the formation of a continuous network between the mineral particles with an "edge–face" orientation. When the surfactant content in the system increases, the ultimate shear stress of the suspension gradually decreases and reaches practically zero values. These results lay the foundation for determining the optimal parameters for the synthesis of iron-containing dispersions based on organomontmorillonite. nZVI was obtained by its reduction on the solid surface of organomodified montmorillonite from a solution of iron(II) sulfate salt. X-ray diffraction data confirmed the fixation of nZVI on the surface of organophilized montmorillonite. Analysis of the results of rheological studies showed that changes in the characteristics of dispersions of iron-containing material based on organomontmorillonite depending on the content of nZVI are extreme and reach a maximum at (6.8 Pa) when the iron content in the sorbent is 0.01 mass fraction in the solid phase of the sorbent. When the content of nZVI is increased to 0.05 mass fraction of the solid phase of the sorbent, it is possible to obtain dispersions with high values of ultimate shear stress (3.3 Pa) and clearly expressed hysteresis loops, which indicates the formation of thixotropic structures and confirms the possibility of its use in permeable reaction barriers. Experimental data confirm that with an increase in the content of nZVI above 0.1 mass fraction in the samples, the ultimate stress and plastic viscosity decrease, which leads to the failure of the suspensions. These results lay foundation for determining the optimal parameters of sorbents synthesis and regulation of their properties by changing the hydrophilic-hydrophobic balance of source systems.Документ Відкритий доступ Persistent organic pollutants: sources, migration in ecosystems, removal methods in wastewater treatment and remediation of soils and natural water(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Litynska, MartaPersistent organic pollutants are among the most dangerous pollutants due to their resistance to destruction in natural conditions, the ability to migrate in ecosystems, bioaccumulation, biomagnification and significant harmful effects on health. Persistent organic pollutants include organochlorine pesticides, polychlorinated naphthalenes, polychlorinated biphenyls, polybrominated diphenyl ethers, polycyclic aromatic hydrocarbons, etc. Even in small amounts, these compounds can cause endocrine disorders and have a carcinogenic effect. Most of these compounds are exclusively of anthropogenic origin. Although the Stockholm Convention has severely restricted the production and use of persistent organic pollutants, many soils and water bodies are already contaminated with these compounds, and some banned substances continue to be produced as byproducts of industrial processes. Also, although the lists of substances prohibited for production are periodically updated, a large number of compounds, which by their properties are persistent organic pollutants, have not yet entered these lists. There are many methods for removing persistent organic pollutants from water, but most of them are insufficiently effective or lead to the generation of large quantities of contaminated waste that need to be disposed of. Photocatalysis is the most promising method of wastewater treatment that contains persistent organic pollutants. Unlike coagulation, adsorption, biological treatment and nanofiltration/reverse osmosis, this method avoids the generation of solid and liquid waste contaminated with these pollutants. In the case of remediation of polluted waters and soils, the main methods are bioremediation and adsorption, since these methods can immobilize persistent organic pollutants directly in the ecosystem without taking soil or water for treatment.Документ Відкритий доступ Fluoride ions removal efficiency of natural/activated zeolite and bentonite sorbents(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Kurylenko, V. S.; Tolstopalova, N. M.; Obushenko, T. I.; Sanginova, O. V.; Dontsova, T. A.Addressing the health concern of fluoride ions contamination in water, that cause such deceases as dental and skeletal fluorosis, requires the development of effective adsorption materials for water treatment. Our research objective was to evaluate the adsorption properties and capacities of zeolite and bentonite, sourced from Ukrainian deposits, and their acid-activated forms in relation to fluoride ions and estimate fitting this data to various adsorption models. Characterization of natural and acid-activated zeolite and bentonite sorbents was performed through X-ray diffraction to determine the phase composition of these substances. Adsorption experiments were carried out at different initial fluoride ions concentrations (3, 5, 10 and 15 mg/l) and pH (3.7; 7.5). Acidification (changing pH from 7.5 to 3.7) increase adsorption capacity of natural zeolite and bentonite more than twice. It was found that natural zeolite removes fluoride ions at the level of 67 % at pH 3.7 and a high dosage of sorbent – 10 g/l and an initial concentration of fluoride ions – 5 mg/l, while its acid-activated form was more effective - the removal of fluoride ions is 86 % at a lower dosage of sorbent – 1 g/l. Similarly, natural bentonite demonstrated a maximum removal efficiency of 45 % at pH 3.7 and a dosage of sorbent – 10 g/l, and its acid-activated form allowed for the removal of fluoride ions of about 83 % at a dosage of sorbent – 2 g/l at the same fluoride ions concentration. It is shown that the Vagelar-Langmuir (VL) isotherm model is the most accurate for describing the process of fluoride ions adsorption by acid-activated forms of natural sorbents, where the R2 values are close to 0.999, indicating monolayer adsorption on homogeneous active centers. The obtained results indicate the greater efficiency of acid-activated forms of natural sorbents and the prospects of their use for the removal of fluoride ions from water.Документ Відкритий доступ Adsorptive and photocatalytic properties of the ZnO/bentonite/Ag heterojunction(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Klimenkov, Oleksiy; Ivanenko, IrynaThe degradation of organic wastewater pollutants from diverse sources represents a critical scientific challenge, particularly in light of the escalating demand for dyes across various industries. Addressing this challenge entails the exploration of efficient and eco-friendly methods to convert organic pollutants into benign and straightforward compounds, leveraging state-of-the-art photocatalysts. The synthesis was conducted via the novel sol-gel method. Structural, crystalline, elemental and phase parameters were analyzed using X-ray analysis, chemical surface characteristics investigated through infrared spectroscopy, band gap determination performed via diffuse reflectance spectroscopy, and evaluation of adsorption and photocatalytic activity carried out for the semiconductor photocatalyst ZnO and heterojunctions incorporating bentonite. The synthesized photocatalysts were employed for the removal of malachite green dye. Equilibrium studies for adsorption were conducted using Langmuir and Freundlich isotherms, revealing a superior fit with the Langmuir model. The maximum adsorption capacity was determined as 70.4 mg/g using the Langmuir equation. Kinetic parameters indicated that the adsorption of malachite green on bentonite followed a first-order kinetics model where k1=0,152 min-1. The photodegradation efficiency of ZnO, ZnO/bentonite, and Zn/bentonite/Ag was investigated by static experiment under ultraviolet irradiation. Within 60 minutes, a 99.4% photodegradation of the malachite green solution at a concentration of 100 mg/L was achieved using the ternary heterojunction photocatalyst. Remarkably, within just 10 minutes in the presence of the ternary composite, a degree of photocatalytic degradation reaching 72% was attained, which significantly exceeds the results of the binary heterojunction photocatalyst. Thus, the synthesized heterojunction exhibits notable photocatalytic activity, particularly evident within short time intervals. A proposed mechanism for the photocatalytic degradation of malachite green is outlined based on existing literature sources.Документ Відкритий доступ Modification methods to enhance the performance of TiO2 in photocatalysis(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Zhou, Z.; Dontsova, T. A.With industrial development and changes in human lifestyle, organic pollution has become an increasingly serious problem, posing a serious threat to the ecological environment and human health. As an emerging advanced oxidation process, titanium dioxide–based photocatalysis has shown unparalleled potential in solving environmental pollution problems due to its stable catalyst properties, mild reaction conditions, environmental friendliness and low cost. However, titanium dioxide is limited in its photocatalytic efficiency by the fact that it can only be excited by ultraviolet light, its carriers are easily compounded and its adsorption capacity is weak. In order to improve the photocatalytic degradation efficiency of organic pollutants, the properties of titanium dioxide can be enhanced by means of modification. This article mainly reviews several major modification methods and research progresses of semiconductor titanium dioxide materials for the degradation performance of organic pollutants in the environment, and focuses on the advantages of the new Metal Organic Frameworks/ titanium dioxide composite system in enhancing the degradation performance of organic pollutants. Finally, the application prospects and key issues of Metal Organic Frameworks/ titanium dioxide materials in photocatalytic treatment of organic pollution problems are presented.Документ Відкритий доступ Water purification from heavy metal ions using lime and PHMG(КПІ ім. Ігоря Сікорського; ТОВ «Українська водна спілка», 2023) Nyzhnyk, T. Y.The method of metal ions' chemical precipitation using polyhexamethylene guanidine (PHMG) and calcium oxide (CaO) was employed for extracting metal ions from concentrated solutions. The order of reagent introduction was found to be crucial in the extraction process, with the best extraction efficiency observed when PHMG was added to water before CaO. This order of addition facilitated the polyelectrolyte effect, resulting in the unfolded conformation of macromolecules and enhancing their interaction with metal ions in solution. Optimal dosage ranges were determined, coinciding with the concentration interval of the polyelectrolyte effect, which maximized the flocculation ability and complex formation of PHMG. The combined use of PHMG and CaO, along with variations in pH, achieved high degrees of metal ion removal (>99%) in a single stage of solution treatment, except for chromium (Cr3+) and cobalt (Co2+). The surface activity of PHMG and ability to transfer metal ions as metal-polymer complexes supported its use in the flotation method for extracting heavy metal ions from low-concentration aqueous solutions. The kinetics of PHMG and metal ion removal by flotation showed rapid binding of metal ions to polymer macromolecules, and regression equations were established to describe the kinetics. The residual concentrations of metal ions after flotation met regulatory sanitary and environmental requirements for wastewater and drinking water. A two-stage scheme for heavy metal ion extraction was developed, involving chemical precipitation and flotation extraction, with a pilot plant designed and manufactured for testing. During wastewater treatment in an electroplating production setting, metal ion concentrations that complied with regulatory standards were achieved.