Перегляд за Автор "Znak, Zenovii"

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    Liophilic and sorptive properties of modified clinoptylolite as a sorbent for water purification from oil and oil products
    (КПІ ім. Ігоря Сікорського ; ТОВ «Українська водна спілка», 2025) Hrynyshyn, Stanislav; Znak, Zenovii
    Oil and oil products pose a serious threat to all components of the environment and people. The most effective for cleaning water environments and solid surfaces from oil and oil products are sorption processes using natural and synthetic materials. This study is aimed at studying the sorption properties of natural zeolite of the clinoptilolite type, modified with an ammonium chloride solution with a concentration of 0.1...1.0 mol/dm3. The effect of modification and fractional composition of clinoptilolite on the lyophilic properties with respect to oil, the mass of sorbed oil, the sorption rate in the initial period of the process, and the sorption capacity were studied. It was shown that, unlike the native form of clinoptilolite, modified sorbent samples in the entire size range are well wetted by oil, followed by complete wetting of the surface of the modified zeolite.With an increase in the dispersion of clinoptilolite, the mass of sorbed oil naturally increases. At the same time, the largest increase in the mass of sorbed oil is observed with a decrease in the average particle size of clinoptilolite from 0.375 to 0.175 mm. It was found that during about 200...240 min of the oil sorption process, the sorption capacity of clinoptilolite increases (up to 0.5...0.7 g/g for different samples). However, further, during the next 2500...2600 min, the calculated sorption capacity formally decreases (up to 0.45...0.6, g/g) with a simultaneous increase in the mass of sorbed oil. Such a formal contradiction is due to the fact that the height of the working layer of clinoptilolite, and therefore the mass of zeolite participating in the sorption, is increasingly increasing. At the same time, during the sorption of oil, which is a polycomponent substance, oil is separated into components on clinoptilolite. Lighter fractions move (chromatographed) faster through the sorbent layer than heavier ones. The studies have confirmed the positive effect of modifying clinoptilolite with ammonium chloride solutions on its sorption capacity. The resulting sorbents have prospects for use in water purification technologies, oil spill cleanup on water surfaces and some solid surfaces.
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    Water purification from hydrogen sulphide using clinoptylolite modified with manganese oxides
    (КПІ ім. Ігоря Сікорського ; ТОВ «Українська водна спілка», 2025) Pyrih, Marta; Znak, Zenovii
    Hydrogen sulphideis contained in many types of groundwater and mine waters. These waters can serve as an additional resource for drinking water, but their thorough purification from hydrogen sulphide is necessary, since the regulatory documents in force in Ukraine do not allow the presence of H2S in drinking water. The most effective methods of water purification from H2S are oxidative-catalytic, in particular, using manganese oxides (MnxOy) deposited on a carrier as a catalyst. The authors developed a new method for modifying sorbents with MnxOyparticles by impregnating natural clinoptilolite with Mn(NO3)2solutions with its subsequent decomposition under the influence of microwave electromagnetic radiation. The resulting sorbent, modified with MnxOyparticles, was used in studies of hydrogen sulphide oxidation in model solutions with a concentration of 10 mg/L. The studies were conducted under anaerobic conditions and in the presence of oxygen, which provided air bubbling at a flow rate of 50 to 300 cm3/min through alayer of modified clinoptilolite, which was located in a glass column. The pH value of the model solution (6.0; 7.0 and 8.5) and temperature (15, 20, 25 and 30 ºС) were also variable parameters. It was found that the value of the rate constant increased not only with increasing temperature and air flow rate, but also with increasing pH of the medium. An increase in pH of the medium causes a decrease in the redox potential of the oxidant, but at the same time contributes to a shift in the equilibrium in theH2S–HS–system towards the ionic form of hydrogen sulphide. This provides a higher rate of its oxidation. The calculated values of the Van't Hoff temperature coefficient (2.0...3.7) and the activation energy of H2S oxidation (53...67 kJ/mol) indicate that theprocess proceeds in the kinetic region. It was established that at pH from 7.0 and above and at an air flow rate of about 200 cm3/min (under experimental conditions), the degree of hydrogen sulphide oxidation within 60 min approaches 100%. Thus, the conducted studies confirmed the high efficiency of the obtained sorbent modified with MnxOyparticles.