The characteristics and properties of fumed oxides depend strongly on various external actions that is of importance from a practical point of view. Therefore, gelation or high-pressure cryogelation (HPC) of aqueous media pure or with 0.1 M NaCl, and mechanochemical activation (MCA) of dry or wetted powders of individual (silica, alumina, their mechanical blends) and complex (silica/titania, alumina/silica/titania, AST1, AST1/A–300) nanooxides were studied to analyze the influence of the nanooxide composition, particulate morphology, and preparation conditions on changes in the morphological and textural characteristics of treated samples. The temperature-pressure behavior of different phases (silica, alumina, and titania) under HPC can result in destroy of complex core-shell nanoparticles (100–200 nm in size) in contrast to small nonporous nanoparticles, NPNP (5–20 nm). The textural characteristics of nanooxides are sensitive to any external actions due to compaction of such supra-NPNP structures as aggregates of nanoparticles, agglomerates of aggregates, and visible structures in powders. The compaction of supra-NPNP enhances the pore volume but much weakly affects the specific surface area (with one exception of AST1) because small NPNP are relatively stable during any external actions (HPC, MCA). The compacted materials are characterized by enhanced mesoporosity shifted to macroporosity with decreasing specific surface area and increasing sizes of nanoparticles or to mesopores with increasing MCA time or amounts of water in wetted powders. At low hydration of the A–300 powder (h = 0.5 g/g), the value of SBET slightly increases if MCA is provided by stirring or ball-milling. Diminution of the freezing temperature from 208 to 77.4 K during HPC results in enhanced compaction of aggregates and agglomerates but this does not practically affect the primary nanoparticles. The degree of decomposition of core-shell nanoparticles of AST1 does not practically increase with decreasing freezing temperature from 208 to 77.4 K. Decomposition of core-shell AST1 particles is inhibited under HPC by added A–300 (1 : 1) working as a damper.
{"title":"Morphologic and textural effects of gelation and mechanochemical activation on dry or wetted simple and complex nanooxides","authors":"V. Gun'ko","doi":"10.15407/hftp13.04.361","DOIUrl":"https://doi.org/10.15407/hftp13.04.361","url":null,"abstract":"The characteristics and properties of fumed oxides depend strongly on various external actions that is of importance from a practical point of view. Therefore, gelation or high-pressure cryogelation (HPC) of aqueous media pure or with 0.1 M NaCl, and mechanochemical activation (MCA) of dry or wetted powders of individual (silica, alumina, their mechanical blends) and complex (silica/titania, alumina/silica/titania, AST1, AST1/A–300) nanooxides were studied to analyze the influence of the nanooxide composition, particulate morphology, and preparation conditions on changes in the morphological and textural characteristics of treated samples. The temperature-pressure behavior of different phases (silica, alumina, and titania) under HPC can result in destroy of complex core-shell nanoparticles (100–200 nm in size) in contrast to small nonporous nanoparticles, NPNP (5–20 nm). The textural characteristics of nanooxides are sensitive to any external actions due to compaction of such supra-NPNP structures as aggregates of nanoparticles, agglomerates of aggregates, and visible structures in powders. The compaction of supra-NPNP enhances the pore volume but much weakly affects the specific surface area (with one exception of AST1) because small NPNP are relatively stable during any external actions (HPC, MCA). The compacted materials are characterized by enhanced mesoporosity shifted to macroporosity with decreasing specific surface area and increasing sizes of nanoparticles or to mesopores with increasing MCA time or amounts of water in wetted powders. At low hydration of the A–300 powder (h = 0.5 g/g), the value of SBET slightly increases if MCA is provided by stirring or ball-milling. Diminution of the freezing temperature from 208 to 77.4 K during HPC results in enhanced compaction of aggregates and agglomerates but this does not practically affect the primary nanoparticles. The degree of decomposition of core-shell nanoparticles of AST1 does not practically increase with decreasing freezing temperature from 208 to 77.4 K. Decomposition of core-shell AST1 particles is inhibited under HPC by added A–300 (1 : 1) working as a damper.","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130498704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An influence of the adsorbed molecules layer on the optical characteristics of the spherical metallic nanoparticles has been studied in the work. In order to do this one considers the additional term which takes into account the scattering of electrons at the interface between metal and adsorbate. The analytical expressions for the frequency dependences for the parameter of coherence loss due to the scattering at the interface “metal – adsorbed layer” have been obtained. It has been found that the presence of the adsorbed molecules results in the electron scattering anisotropy, and, hence, in the anisotropy of the optic response of such systems. The result of the indicated anisotropy is the appearance of the additional maximum in the infrared part of the spectrum in the frequency dependences for the optical characteristics. An evolution of the frequency dependences for the components of the polarizability tensor and the absorption cross-section and scattering cross-section for the two-layer spherical nanoparticles of the type “metal – adsorbate” under the variation of their geometrical parameters has been analyzed. It has been shown that the weak maximum of the real, imaginary parts and the module of the transverse component of the polarizability tensor and the absorption and scattering cross-sections in the infrared part of the spectrum appears due to inducing of the local density of the states by adsorbate. The reason of the shift of the maxima of the absorption cross-section and scattering cross-section for the nanoparticles of the constant sizes with the cores of different metals has been found. It has been demonstrated the existence of the small-scale oscillations at the frequency dependences for the components of the polarizability tensor and at the absorption and scattering cross-sections, caused by an oscillating contribution of the surface electron scattering. The dependence of the location and the value of the maximum of the absorption cross-section for the particle “metal – adsorbate” with the constant geometrical parameters and content on the dielectric permittivity of the medium, in which the nanoparticle is situated, has been proved.
{"title":"An influence of the adsorbed molecules layer on the localized surface plasmons in the spherical metallic nanoparticles","authors":"N. Smirnova, A. Korotun, L. M. Titov","doi":"10.15407/hftp13.04.476","DOIUrl":"https://doi.org/10.15407/hftp13.04.476","url":null,"abstract":"An influence of the adsorbed molecules layer on the optical characteristics of the spherical metallic nanoparticles has been studied in the work. In order to do this one considers the additional term which takes into account the scattering of electrons at the interface between metal and adsorbate. The analytical expressions for the frequency dependences for the parameter of coherence loss due to the scattering at the interface “metal – adsorbed layer” have been obtained. It has been found that the presence of the adsorbed molecules results in the electron scattering anisotropy, and, hence, in the anisotropy of the optic response of such systems. The result of the indicated anisotropy is the appearance of the additional maximum in the infrared part of the spectrum in the frequency dependences for the optical characteristics. An evolution of the frequency dependences for the components of the polarizability tensor and the absorption cross-section and scattering cross-section for the two-layer spherical nanoparticles of the type “metal – adsorbate” under the variation of their geometrical parameters has been analyzed. It has been shown that the weak maximum of the real, imaginary parts and the module of the transverse component of the polarizability tensor and the absorption and scattering cross-sections in the infrared part of the spectrum appears due to inducing of the local density of the states by adsorbate. The reason of the shift of the maxima of the absorption cross-section and scattering cross-section for the nanoparticles of the constant sizes with the cores of different metals has been found. It has been demonstrated the existence of the small-scale oscillations at the frequency dependences for the components of the polarizability tensor and at the absorption and scattering cross-sections, caused by an oscillating contribution of the surface electron scattering. The dependence of the location and the value of the maximum of the absorption cross-section for the particle “metal – adsorbate” with the constant geometrical parameters and content on the dielectric permittivity of the medium, in which the nanoparticle is situated, has been proved.","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131356803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ol. D Zolotarenk, E. Rudakova, N. Akhanova, A. Zolotarenko, D. Shchur, M. Gabdullin, M. Ualkhanova, N. Gavrylyuk, M. Chymbai, T. Myronenko, I. Zagorulko, A. Zolotarenko, O. Havryliuk
The mechanical mixtures of titanium oxide (TiO2) with carbon nanostructures for 3D printing of CJP technology, which are used as consumables for the manufacturing of electrically conductive composite 3D products, are created in this work. Various carbon nanostructures (single- and multi-walled carbon nanotubes and carbon nanofibers) were used in the creation of composite 3D products (TiO2–СNS) by CJP 3D printing technology. Optimal conditions for processing of mechanical mixtures (TiO2/MWCNT) on a planetary ball mixer for composite 3D products (CJP) were studied and proposed. The dose of the deformation influence on the mechanical mixture under optimal conditions of mechanochemical processing (76 J/g), which allows not to deteriorate the electrical conductivity of the material, is determined. The dependence of the electrical conductivity of composite 3D products (CNS/TiO2, where the CNS content is 3 wt. %) on the type of carbon nanostructures (SWCNT, MWCNT and CNF) contained in ceramics (TiO2), is constructed. The exponential dependence of the specific electrical conductivity (G) of composite 3D products (TiO2–MWCNT) on the mass content of multi-walled carbon nanotubes, is also recorded in the work. In the framework of the study of the electrical conductivity of composite 3D products (CJP), a fuel cell cathode based on a Pt/TiO2–MWCNT composite was created. It was found that the catalyst Pt/TiO2–MWCNT, which contains 5 wt. % of carbon nanotubes, has the best catalytic activity in oxygen recovery. At the same time, the average particle size of platinum (Pt) is 5–10 nm, while the content of Pt in the EDX samples is approximately ~10 wt. %. Also, studies were carried out from the mixing of Pt/TiO2-MWCNT composites with MWCNT content 15 and 50 wt. %. Samples were analyzed by transmission and scanning electron microscopy.
{"title":"Electrically conductive composites based on TiO2 and carbon nanostructures manufactured using 3D printing of CJP technology","authors":"Ol. D Zolotarenk, E. Rudakova, N. Akhanova, A. Zolotarenko, D. Shchur, M. Gabdullin, M. Ualkhanova, N. Gavrylyuk, M. Chymbai, T. Myronenko, I. Zagorulko, A. Zolotarenko, O. Havryliuk","doi":"10.15407/hftp13.04.415","DOIUrl":"https://doi.org/10.15407/hftp13.04.415","url":null,"abstract":"The mechanical mixtures of titanium oxide (TiO2) with carbon nanostructures for 3D printing of CJP technology, which are used as consumables for the manufacturing of electrically conductive composite 3D products, are created in this work. Various carbon nanostructures (single- and multi-walled carbon nanotubes and carbon nanofibers) were used in the creation of composite 3D products (TiO2–СNS) by CJP 3D printing technology. Optimal conditions for processing of mechanical mixtures (TiO2/MWCNT) on a planetary ball mixer for composite 3D products (CJP) were studied and proposed. The dose of the deformation influence on the mechanical mixture under optimal conditions of mechanochemical processing (76 J/g), which allows not to deteriorate the electrical conductivity of the material, is determined. The dependence of the electrical conductivity of composite 3D products (CNS/TiO2, where the CNS content is 3 wt. %) on the type of carbon nanostructures (SWCNT, MWCNT and CNF) contained in ceramics (TiO2), is constructed. The exponential dependence of the specific electrical conductivity (G) of composite 3D products (TiO2–MWCNT) on the mass content of multi-walled carbon nanotubes, is also recorded in the work. In the framework of the study of the electrical conductivity of composite 3D products (CJP), a fuel cell cathode based on a Pt/TiO2–MWCNT composite was created. It was found that the catalyst Pt/TiO2–MWCNT, which contains 5 wt. % of carbon nanotubes, has the best catalytic activity in oxygen recovery. At the same time, the average particle size of platinum (Pt) is 5–10 nm, while the content of Pt in the EDX samples is approximately ~10 wt. %. Also, studies were carried out from the mixing of Pt/TiO2-MWCNT composites with MWCNT content 15 and 50 wt. %. Samples were analyzed by transmission and scanning electron microscopy.","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130759993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The structure of water in the interparticle gaps of methyl silica was investigated using the method of low-temperature 1H NMR spectroscopy. It is shown that the main part of the interfacial water is in the form of large clusters, or nanodroplets, which freeze at a temperature of about 273 K. After freezing of this water, signals of strongly and weakly associated water are observed in the spectra, which melts at temperatures of 215–368 K. It is likely that the freezing of weakly associated of water occurs through the formation of clusters in which closely spaced water molecules interact not through hydrogen bonds, but through dipole-dipole interactions. In the presence of chloroform, the amount of weakly associated water increases several times. This is explained by the possibility of formation of chloroform hydrates, in which the mobility of water molecules is approximately the same as in strongly associated water clusters. If joint adsorption of chloroform and methane occurs on the hydrated surface of methyl silica, under the influence of CH4, weakly mobile weakly associated water is transformed into methane hydrates in quasi-liquid and solid states, while only mobile forms of hydrates are recorded in the spectra. DMSO reduces the possibility of formation of weakly associated water, but a certain amount of it is fixed even in the medium of liquid DMSO. At the same time, the freezing of water in systems containing DMSO occurs at much lower temperatures due to solvation of water and DMSO molecules. The difference in interphase energy in air and in organic media determines the solvation energy.
{"title":"Water in a hydrophobic environment and the effect of some organic substances on it","authors":"V. Turov, T. Krupska","doi":"10.15407/hftp13.04.405","DOIUrl":"https://doi.org/10.15407/hftp13.04.405","url":null,"abstract":"The structure of water in the interparticle gaps of methyl silica was investigated using the method of low-temperature 1H NMR spectroscopy. It is shown that the main part of the interfacial water is in the form of large clusters, or nanodroplets, which freeze at a temperature of about 273 K. After freezing of this water, signals of strongly and weakly associated water are observed in the spectra, which melts at temperatures of 215–368 K. It is likely that the freezing of weakly associated of water occurs through the formation of clusters in which closely spaced water molecules interact not through hydrogen bonds, but through dipole-dipole interactions. In the presence of chloroform, the amount of weakly associated water increases several times. This is explained by the possibility of formation of chloroform hydrates, in which the mobility of water molecules is approximately the same as in strongly associated water clusters. If joint adsorption of chloroform and methane occurs on the hydrated surface of methyl silica, under the influence of CH4, weakly mobile weakly associated water is transformed into methane hydrates in quasi-liquid and solid states, while only mobile forms of hydrates are recorded in the spectra. DMSO reduces the possibility of formation of weakly associated water, but a certain amount of it is fixed even in the medium of liquid DMSO. At the same time, the freezing of water in systems containing DMSO occurs at much lower temperatures due to solvation of water and DMSO molecules. The difference in interphase energy in air and in organic media determines the solvation energy.","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125660362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Kusyak, A. Petranovska, S. P. Turanska, O. Oranska, Y. M. Shuba, D. I. Kravchuk, L. I. Kravchuk, V. Nazarenko, R. M. Kravchuk, V. A. Dubok, V. Chornyi, O. A. Bur'yanov, Yu. L. Sobolevs’kyy, P. Gorbyk
The purpose of the work is the synthesis of samples of X-ray luminescent nanodispersed lanthanum phosphate activated with terbium (LaРО4:Tb3+), the study of their structural properties and luminescence spectra when excited by ultraviolet and X-ray radiation, as well as determination of the possibility of their use in nanocomposites with bioactive glass and colloidal nanosystems. Samples of nanocrystalline lanthanum phosphate were synthesized composed of LaPO4·0.5H2O, of hexagonal syngonium, activated with terbium, their structural properties, luminescence spectra were studied upon excitation by UV and X-ray radiation, a possibility was shown to use them in nanocomposites with bioactive sol-gel glass and aqueous colloidal systems. Composites of 60S bioglass with nanodispersed crystalline LaPO4:Tb3+ in the dry state and in distilled water medium demonstrated the presence of luminescence when excited by UV and X-ray radiation. The given data indicate the perspective of nanodispersed phosphors based on lanthanum phosphate, their composites with bioactive sol-gel glass in colloidal systems, for use in optopharmacology and photodynamic therapy of diseases localized in bone tissues. In addition, the results of research can be useful for technical applications, in particular, in the creation of luminescent detectors of high-energy electromagnetic radiation, development of photo- and optoelectronic devices, etc.
{"title":"Synthesis, properties and application possibilities of X-ray luminescent nanocrystalline lanthanum phosphate","authors":"A. Kusyak, A. Petranovska, S. P. Turanska, O. Oranska, Y. M. Shuba, D. I. Kravchuk, L. I. Kravchuk, V. Nazarenko, R. M. Kravchuk, V. A. Dubok, V. Chornyi, O. A. Bur'yanov, Yu. L. Sobolevs’kyy, P. Gorbyk","doi":"10.15407/hftp13.04.425","DOIUrl":"https://doi.org/10.15407/hftp13.04.425","url":null,"abstract":"The purpose of the work is the synthesis of samples of X-ray luminescent nanodispersed lanthanum phosphate activated with terbium (LaРО4:Tb3+), the study of their structural properties and luminescence spectra when excited by ultraviolet and X-ray radiation, as well as determination of the possibility of their use in nanocomposites with bioactive glass and colloidal nanosystems. Samples of nanocrystalline lanthanum phosphate were synthesized composed of LaPO4·0.5H2O, of hexagonal syngonium, activated with terbium, their structural properties, luminescence spectra were studied upon excitation by UV and X-ray radiation, a possibility was shown to use them in nanocomposites with bioactive sol-gel glass and aqueous colloidal systems. Composites of 60S bioglass with nanodispersed crystalline LaPO4:Tb3+ in the dry state and in distilled water medium demonstrated the presence of luminescence when excited by UV and X-ray radiation. The given data indicate the perspective of nanodispersed phosphors based on lanthanum phosphate, their composites with bioactive sol-gel glass in colloidal systems, for use in optopharmacology and photodynamic therapy of diseases localized in bone tissues. In addition, the results of research can be useful for technical applications, in particular, in the creation of luminescent detectors of high-energy electromagnetic radiation, development of photo- and optoelectronic devices, etc.","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126797399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Suchikova, S. Kovachov, I. Bardus, A. Lazarenko, I. Bohdanov
We report the synthesis of β-SiC/por-Si/mono-Si heterostructure by a hybrid method, consisting of the electrochemical etching of the single-crystal silicon surface with a subsequent carbidization by a thermal annealing in a methane atmosphere. This method has a number of advantages over the known ones, because it is cheap enough and allows one to form the silicon carbide layers of high- quality. The formed structure was studied by means of SEM, EDX and XRD methods. As a result, the dense β-SiC layer, consisting of an array of the spherical islands with diameters of 2–6 μm, coated with the small pores, was formed on the por-Si/mono-Si surface. The geometric dimensions of the islands were studied by calibrating the sample image in the ImageJ software package. The maximum value of the linear size (diameter) of the island dmax = 5.95 μm and the minimum value dmin = 2.11 μm were found in the studied area. In general, the average diameter of the islands is d = 3.72 μm. The distribution has the left-sided asymmetry, that is, the smaller islets predominate. Roundness (the ratio of the area to the square of the larger axis) R = 0.86. According to the results of EDX analysis, it was found that the synthesized structure surface consists exclusively of the carbon and silicon atoms, indicating the high quality of the formed structures. It was found that the SiC film crystallizes in the cubic phase. The formation of the islands is explained by means of the layer-plus-island growth model according to Stranski-Krastanow mechanism, which is characterized by the formation of the dense wetting layer with the massive island complex on the surface. It should be also noted that the porous SiC layers of island type can, in turn, show the perspective as the buffers with the heteroepitaxy of the silicon substrate materials.
{"title":"Formation of β-SiC on por-Si/mono-Si surface according to stranski - krastanow mechanism","authors":"Y. Suchikova, S. Kovachov, I. Bardus, A. Lazarenko, I. Bohdanov","doi":"10.15407/hftp13.04.447","DOIUrl":"https://doi.org/10.15407/hftp13.04.447","url":null,"abstract":"We report the synthesis of β-SiC/por-Si/mono-Si heterostructure by a hybrid method, consisting of the electrochemical etching of the single-crystal silicon surface with a subsequent carbidization by a thermal annealing in a methane atmosphere. This method has a number of advantages over the known ones, because it is cheap enough and allows one to form the silicon carbide layers of high- quality. The formed structure was studied by means of SEM, EDX and XRD methods. As a result, the dense β-SiC layer, consisting of an array of the spherical islands with diameters of 2–6 μm, coated with the small pores, was formed on the por-Si/mono-Si surface. The geometric dimensions of the islands were studied by calibrating the sample image in the ImageJ software package. The maximum value of the linear size (diameter) of the island dmax = 5.95 μm and the minimum value dmin = 2.11 μm were found in the studied area. In general, the average diameter of the islands is d = 3.72 μm. The distribution has the left-sided asymmetry, that is, the smaller islets predominate. Roundness (the ratio of the area to the square of the larger axis) R = 0.86. According to the results of EDX analysis, it was found that the synthesized structure surface consists exclusively of the carbon and silicon atoms, indicating the high quality of the formed structures. It was found that the SiC film crystallizes in the cubic phase. The formation of the islands is explained by means of the layer-plus-island growth model according to Stranski-Krastanow mechanism, which is characterized by the formation of the dense wetting layer with the massive island complex on the surface. It should be also noted that the porous SiC layers of island type can, in turn, show the perspective as the buffers with the heteroepitaxy of the silicon substrate materials.","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129163106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Eprikashvili, G. Tsintskaladze, T. Kordzakhia, M. Zautashvili, N. Pirtskhalava, M. Dzagania, T. M. Sharashenidze
Wastewater and natural waters contain various pollutants of both natural and artificial origin. Treatment of these waters is carried out comprehensively by various methods, which significantly increases costs. Currently, the problem of a large amount of drugs entering the wastewater is very relevant. Drugs, unchanged or in the form of metabolites, enter the wastewater together with the waste products of a living organism. To solve urgent practical problems of water purification, a possibility of using natural zeolite materials as sorbents has been recently considered. Being a natural aluminosilicates of frame-type structure, these minerals have a number of unique adsorption properties that can be used in water treatment processes. Treatment with acid solutions (alkalis, salt solutions and some organic compounds) allows to improve significantly their sorption characteristics for decision of a particular problem. Zeolites, being chemically stable minerals, are capable to withstand the effects of chemically active medium without destruction of the crystal lattice. The effect of boiling acid (HC1) on natural zeolites from Georgian deposits (mordenite and clinoptilolite) and the possibility of their use for adsorption treatment of wastewater were studied in this work. Identification of modified zeolites was carried out on the basis of X-ray diffractograms and IR-spectra. It has been shown that natural clinoptilolites (mordenite and zeolite) are characterized by high thermostability and acid resistance even after acid-modification, and the resulting hydrogen forms are distinguished by high concentration of active centers; the efficiency of adsorption method for wastewater treatment from some pharmacopolutants when using acid-modified natural zeolites has been also shown. This method will solve the problem of entering the environment of drugs with lower costs
{"title":"Effect of acid modification of natural zeolites on the adsorption of some pharmacopollutants","authors":"L. Eprikashvili, G. Tsintskaladze, T. Kordzakhia, M. Zautashvili, N. Pirtskhalava, M. Dzagania, T. M. Sharashenidze","doi":"10.15407/hftp13.04.498","DOIUrl":"https://doi.org/10.15407/hftp13.04.498","url":null,"abstract":"Wastewater and natural waters contain various pollutants of both natural and artificial origin. Treatment of these waters is carried out comprehensively by various methods, which significantly increases costs. Currently, the problem of a large amount of drugs entering the wastewater is very relevant. Drugs, unchanged or in the form of metabolites, enter the wastewater together with the waste products of a living organism. To solve urgent practical problems of water purification, a possibility of using natural zeolite materials as sorbents has been recently considered. Being a natural aluminosilicates of frame-type structure, these minerals have a number of unique adsorption properties that can be used in water treatment processes. Treatment with acid solutions (alkalis, salt solutions and some organic compounds) allows to improve significantly their sorption characteristics for decision of a particular problem. Zeolites, being chemically stable minerals, are capable to withstand the effects of chemically active medium without destruction of the crystal lattice. The effect of boiling acid (HC1) on natural zeolites from Georgian deposits (mordenite and clinoptilolite) and the possibility of their use for adsorption treatment of wastewater were studied in this work. Identification of modified zeolites was carried out on the basis of X-ray diffractograms and IR-spectra. It has been shown that natural clinoptilolites (mordenite and zeolite) are characterized by high thermostability and acid resistance even after acid-modification, and the resulting hydrogen forms are distinguished by high concentration of active centers; the efficiency of adsorption method for wastewater treatment from some pharmacopolutants when using acid-modified natural zeolites has been also shown. This method will solve the problem of entering the environment of drugs with lower costs","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133451118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Tsintskaladze, T. Sharashenidze, L. Eprikashvili, M. Zautashvili, T. Kordzakhia, M. Dzagania
Phosphates are specific compounds of the composition of living organisms, that play a special role in plant and animal life. The skeleton of most living organisms consists mainly of calcium, sodium, magnesium and other phosphates. Because phosphorus plays an important role in supplying nutrients to the environment, it is central to all forms of life. Therefore, interest in this type of material is great, and the scope of application is enormous, from agriculture to medicine. On the basis of clinoptilolite, a natural zeolite located in Georgia, zeolitic nanomaterials containing phosphates were obtained by two different methods. The first method is the introduction of mono-, di-, and tri-substituted sodium phosphates into the zeolite structure under conditions of boiling on a sand bath, where the introduction of phosphate ions is difficult. In the second method, phosphate ions almost completely occupy the inner structural area of the zeolite. The zeolitic nanoporous materials of mono-substituted, di-substituted and tri-substituted phosphates obtained by these methods and subsequently studied by Fourier spectroscopic method. The obtained materials have preserved the zeolitic structure, although their IR spectra are sharply different from each other, which can be explained by different anions occupying different positions in the zeolitic structure. It should be noted that after washing the obtained material with water, phosphate ions are almost completely washed out of the zeolite structure. The importance of the received materials and the perspective of their use are given.
{"title":"Study on the structure of phosphorus-containing zeolite anionic nanoporous materials","authors":"G. Tsintskaladze, T. Sharashenidze, L. Eprikashvili, M. Zautashvili, T. Kordzakhia, M. Dzagania","doi":"10.15407/hftp13.04.506","DOIUrl":"https://doi.org/10.15407/hftp13.04.506","url":null,"abstract":"Phosphates are specific compounds of the composition of living organisms, that play a special role in plant and animal life. The skeleton of most living organisms consists mainly of calcium, sodium, magnesium and other phosphates. Because phosphorus plays an important role in supplying nutrients to the environment, it is central to all forms of life. Therefore, interest in this type of material is great, and the scope of application is enormous, from agriculture to medicine. On the basis of clinoptilolite, a natural zeolite located in Georgia, zeolitic nanomaterials containing phosphates were obtained by two different methods. The first method is the introduction of mono-, di-, and tri-substituted sodium phosphates into the zeolite structure under conditions of boiling on a sand bath, where the introduction of phosphate ions is difficult. In the second method, phosphate ions almost completely occupy the inner structural area of the zeolite. The zeolitic nanoporous materials of mono-substituted, di-substituted and tri-substituted phosphates obtained by these methods and subsequently studied by Fourier spectroscopic method. The obtained materials have preserved the zeolitic structure, although their IR spectra are sharply different from each other, which can be explained by different anions occupying different positions in the zeolitic structure. It should be noted that after washing the obtained material with water, phosphate ions are almost completely washed out of the zeolite structure. The importance of the received materials and the perspective of their use are given.","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126211742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A theory of exciton quasimolecules (formed from spatially separated electrons and holes) in a nanosystem consisting of double quantum dots (QDs) of germanium synthesized in a silicon matrix is presented. It is shown that the binding energy of the singlet ground state of the quasimolecule of an exciton is considerably larger than the binding energy of biexciton in a silicon single crystal by almost two orders of magnitude. It is shown that the exciton quasimolecule formation is of the threshold character and possible in a nanosystem, where D is the distance between the surfaces of QD that satisfies the following condition: (where and are some critical distances). Using the variational method, we obtain the binding energy of the exciton quasimolecule singlet ground state of the system as a function of the distance between the surfaces of QD D, and the QD radius a. It is shown that the convergence of two QDs up to a certain critical value of the distance between the surfaces of QD DC leads to the effective overlapping of the electron wave functions and the appearance of exchange interactions. As a result, the exciton quasimolecules can be formed from the QDs. It is shown that the existence of such a critical distance DC arises from the quantum size effects. Dimensional quantization of electrons and holes motion leads to the following fact: as the distance between the surfaces of the QD DC decreases, the decrease in the energies of interaction of the electrons and holes entering into the Hamiltonian of the exciton quasimolecule cannot compensate for the increase in the kinetic energy of the electrons and holes. At larger values of the distance between the surfaces of the QD D, , the exciton quasimolecule breaks down into two excitons (consisting of spatially separated electrons and holes), localized over the QD surfaces. The fact that the energy of the ground state of singlet excitonic quasimolecule is in the infrared range of the spectrum, presumably, allows us to use a quasimolecule for the development of new elements of silicon infrared nanooptoelectronics.
{"title":"On the theory of the binding energy of exciton quasimolecules in germanium/silicon double quantum dots","authors":"S. Pokutnyi, N. Shkoda, J. Usik","doi":"10.15407/hftp13.04.383","DOIUrl":"https://doi.org/10.15407/hftp13.04.383","url":null,"abstract":"A theory of exciton quasimolecules (formed from spatially separated electrons and holes) in a nanosystem consisting of double quantum dots (QDs) of germanium synthesized in a silicon matrix is presented. It is shown that the binding energy of the singlet ground state of the quasimolecule of an exciton is considerably larger than the binding energy of biexciton in a silicon single crystal by almost two orders of magnitude. It is shown that the exciton quasimolecule formation is of the threshold character and possible in a nanosystem, where D is the distance between the surfaces of QD that satisfies the following condition: (where and are some critical distances). Using the variational method, we obtain the binding energy of the exciton quasimolecule singlet ground state of the system as a function of the distance between the surfaces of QD D, and the QD radius a. It is shown that the convergence of two QDs up to a certain critical value of the distance between the surfaces of QD DC leads to the effective overlapping of the electron wave functions and the appearance of exchange interactions. As a result, the exciton quasimolecules can be formed from the QDs. It is shown that the existence of such a critical distance DC arises from the quantum size effects. Dimensional quantization of electrons and holes motion leads to the following fact: as the distance between the surfaces of the QD DC decreases, the decrease in the energies of interaction of the electrons and holes entering into the Hamiltonian of the exciton quasimolecule cannot compensate for the increase in the kinetic energy of the electrons and holes. At larger values of the distance between the surfaces of the QD D, , the exciton quasimolecule breaks down into two excitons (consisting of spatially separated electrons and holes), localized over the QD surfaces. The fact that the energy of the ground state of singlet excitonic quasimolecule is in the infrared range of the spectrum, presumably, allows us to use a quasimolecule for the development of new elements of silicon infrared nanooptoelectronics.","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134280937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Tsitsishvili, N. Dolaberidze, N. Mirdzveli, M. Nijaradze, Z. Amiridze, B. Khutsishvili
The coronavirus pandemic has increased interest in antibacterial agents containing bioactive metals, for which zeolites are promising carriers. On the other hand, zeolite adsorbents and ion exchangers containing bioactive metals and endowed with bactericidal properties are promising for water treatment and other environmental and medical applications.Silver-, copper-, and zinc-containing microporous materials have been prepared on the base of natural analcime,phillipsite and heulandite from Georgian manifestations using ion-exchange reactions between zeolite microcrystals and a salt of a corresponding transition metal in the solid phase followed by washing with distilled water. Synthesized in such way adsorbent-ion-exchangers are characterized by chemical composition based on the X-ray energy dispersion spectra, powder X-ray diffraction patterns, Fourier transform infra-red spectra and low-temperature adsorption-desorption isotherms of N2. Obtained materials remain the zeolite crystal structure and contain 130–230 mg/g of silver, 65–72 mg/g of copper, and 58–86 mg/g of zinc, as compared with modified samples of synthetic type A zeolite containing up to 380 mg/g of silver, 150 mg/g of copper, and 150 mg/g of zinc. Prepared metal-containing materials show bacteriostatic activity against Gram negative bacterium Escherichia coli, Gram positive bacteria Staphylococcus aureus and Bacillus subtilis, fungal pathogenic yeastCandida albicans, and a fungus Aspergilusniger, and natural zeolites enriched with biometals exhibit a synergistic effect – their mixtures have a higher bacteriostatic activity. It is shown that mixtures of copper and zinc forms have a higher activity than the silver-containing form, which is very important from a practical point of view for replacing expensive silver with cheaper copper and zinc. It has been found that the bacteriostatic activity of metal-containing zeolites is determined not only and not so much by the ions of bioactive metals released into the liquid medium, but an important role ininhibiting the growth of microorganisms plays a type of zeolite matrix. Despite the relatively low ion-exchange capacity, heulandite turned out to be a fairly effective matrix for bioactive metals.
{"title":"Bactericidal metal-containing zeolites","authors":"V. Tsitsishvili, N. Dolaberidze, N. Mirdzveli, M. Nijaradze, Z. Amiridze, B. Khutsishvili","doi":"10.15407/hftp13.04.489","DOIUrl":"https://doi.org/10.15407/hftp13.04.489","url":null,"abstract":"The coronavirus pandemic has increased interest in antibacterial agents containing bioactive metals, for which zeolites are promising carriers. On the other hand, zeolite adsorbents and ion exchangers containing bioactive metals and endowed with bactericidal properties are promising for water treatment and other environmental and medical applications.Silver-, copper-, and zinc-containing microporous materials have been prepared on the base of natural analcime,phillipsite and heulandite from Georgian manifestations using ion-exchange reactions between zeolite microcrystals and a salt of a corresponding transition metal in the solid phase followed by washing with distilled water. Synthesized in such way adsorbent-ion-exchangers are characterized by chemical composition based on the X-ray energy dispersion spectra, powder X-ray diffraction patterns, Fourier transform infra-red spectra and low-temperature adsorption-desorption isotherms of N2. Obtained materials remain the zeolite crystal structure and contain 130–230 mg/g of silver, 65–72 mg/g of copper, and 58–86 mg/g of zinc, as compared with modified samples of synthetic type A zeolite containing up to 380 mg/g of silver, 150 mg/g of copper, and 150 mg/g of zinc. Prepared metal-containing materials show bacteriostatic activity against Gram negative bacterium Escherichia coli, Gram positive bacteria Staphylococcus aureus and Bacillus subtilis, fungal pathogenic yeastCandida albicans, and a fungus Aspergilusniger, and natural zeolites enriched with biometals exhibit a synergistic effect – their mixtures have a higher bacteriostatic activity. It is shown that mixtures of copper and zinc forms have a higher activity than the silver-containing form, which is very important from a practical point of view for replacing expensive silver with cheaper copper and zinc. It has been found that the bacteriostatic activity of metal-containing zeolites is determined not only and not so much by the ions of bioactive metals released into the liquid medium, but an important role ininhibiting the growth of microorganisms plays a type of zeolite matrix. Despite the relatively low ion-exchange capacity, heulandite turned out to be a fairly effective matrix for bioactive metals.","PeriodicalId":296392,"journal":{"name":"Himia, Fizika ta Tehnologia Poverhni","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128663426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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