“Green” synthesis of silver nanoparticles (AgNPs) by a galvanic replacement (GR) on magnesium in solutions of sodium polyacrylate (NaPA) under ultrasound (42 kHz) is reported. The mechanism of combined action of GR and ultrasound on the formation of nanoparticles is proposed. Synthesized solutions of AgNPs are characterized by an absorption maximum at 410 nm, the value of which does not depend on the concentrations of precursors (AgNO3 and NaPA) and the duration of the process. The dimensions of nanoparticles that have a spherical shape do not exceed 30 nm.
The regularities of cavitation treatment of food and chemical industries wastewater from organic and biological contaminants in the presence of gases of different nature were studied. The optimal temperature range 313K - 318 K for cavitation wastewater treatment was established. It is shown that the process of cavitation destruction of organic compounds can be described by a first - order kinetic equation.
The regularities of the change of the concentration of microorganisms and water-soluble organic compounds in the polluted water in the conditions of cavitation treatment and the influence of the amount of biological water pollution on the value of the chemical oxygen consumption are investigated.
Sonogalvanic replacement and galvanic replacement synthesis of silver nanoparticles (AgNPs) by magnesium scrap in sodium polyacrylate solutions were studied. It was found that during these processes in NaPA solutions silver is practically not deposited on the magnesium surface. Sodium polyacrylate provides stabilization of AgNPs with the formation of yellow solutions with maximum absorption of ~415 nm.
The grafted copolymerization of 2-hydroxyethyl methacrylate to polyvinylpyrrolidone in the presence of mineral fillers (hydroxyapatite, montmorillonite and wollastonite) under ultrasound has been investigated. The effect of ultrasound, nature and amount of mineral filler on the polymerization rate and composition of copolymers has been determined. Ultrasound substantially intensifies the polymerization process and actively affects the formation of the copolymer composition. Under its action, a porous structure of composites is formed, even without adding special foaming agents.
The mechanism of water sonolysis with the formation of both intermediates (free radicals) and basic products (hydrogen and oxygen), which are important for thermal power engineering and water purification technologies, based on the use of advanced oxidation processes, wasresearched. The efficiency of hydroxyl radical generation in the environment of inert gases and oxygen was analyzed.
The article analyzes the topicality of the primary standard creation of the ultrasonic pressure unit in water for the frequency range of 0.5–10.0 MHz in Ukraine. Its creation is predetermined by the necessity of the exploited ultrasound medical equipment metrological maintenance as well as for the assessment of compliance with the requirements of the technical regulations for medical products to be exploited.
This research presents that the higher temperature results on higher extracted anthocyanin. In addition, it was found that pH 2 was preferable for obtaining greater anthocyanin content. Employing the second-order kinetics model in this research confirmed the good fitting of the model and experimental data.
The influence of cavitation on a decrease of the number of microorganism colonies has been investigated. Our results have shown that the number of viable microorganisms in water dispersion during first 30 minutes of sonication increased till maximum. Then their quantity sharply decreased. A kinetic model of ultrasonic degradation of yeast cells aggregates was proposed.
The regularities of obtaining of osteoplastic porous composites based on 2-hydroxyethyl methacrylate with polyvinylpyrrolidone copolymers in the presence of mineral fillers (hydroxyapatite, montmorillonite and wollastonite) under ultrasound are researched. The influence of ultrasound, nature and amount of inorganic filler on the polymerization rate, copolymers composition and composites porosity has been determined. It was found that homopolymerization of 2-hydroxyethyl methacrylate without filler under ultrasound action does not occur in experiment conditions.