A mesoporous silica support was synthesized using the sol-gel method from trichlorosilane. There is a tendency for the specific surface area and the proportion of silica particles mesopores to ...increase during all stages of sol-gel synthesis. It has been shown that the insertion of hexane and toluene, as additional solvents, into the structure-forming polyethylene glycol, makes it possible to regulate the pore size and specific surface area of silica. Silica functionalization was carried out using SILP technology. The activities of the catalytic systems based on polymer and inorganic supports immobilized by imidazole-based ionic liquids during the trichlorosilane disproportionation reaction were compared. There is a tendency for the monosilane yield for catalytic systems based on an inorganic support to increase. We identified the most promising catalyst in terms of monosilane yield and proposed a bifunctional catalyst that exhibited activity in two parallel reactions: trichlorosilane disproportionation and silicon tetrachloride hydrogenation.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The current investigation is focused on the development of composite membranes based on polymeric ionic liquids (PILs) containing imidazolium and pyridinium polycations with various counterions, ...including hexafluorophosphate, tetrafluoroborate, and bis(trifluoromethylsulfonyl)imide. A combination of spectroscopic methods was used to identify the synthesized PILs and characterize their interaction with carbon dioxide. The density and surface free energy of polymers were performed by wettability measurements, and the results are in good agreement with the permeability and selectivity obtained within the gas transport tests. It was shown that the membranes with a selective layer based on PILs exhibit relatively high permeability with CO2 and high ideal selectivity CO2/CH4 and CO2/N2. Additionally, it was found that the type of an anion significantly affects the performance of the obtained membranes, with the most pronounced effect from bis-triflimide-based polymers, showing the highest permeability coefficient. These results provide valuable insights into the design and optimization of PIL-based membranes for natural and flue gas treatment.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This work explored the zinc nanoparticles obtained by the one-stage induction flow levitation method. A 10 kW tube generator with an operating frequency of 440 kHz was used. The process used 8 mm ...diameter zinc granules (2 g weight) with a purity of 99.9%. Zinc wire was fed to replace the evaporated metal from the granule surface. This method productivity was 30 g/h of nanoparticles. In addition, various methods were used to characterize the resulting nanoparticles: scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray fluorescence analysis (XRF), dynamic light scattering (DLS), porosimetry and inductively coupled plasma atomic emission spectroscopy (ICP-MS). The resulting nanoparticle size, determined by SEM and porosimetry, was 350 nm, while the size of the primary crystallites was 21 nm. The amount of impurities in the resulting nanoparticles did not exceed 1000 ppm.
The present research provides data on the density (ρ), viscosity (η) and ability to absorb carbon dioxide of systems containing amine, molecular solvent (MS) and choline chloride (ChCl), with the ...investigation of the physical properties of both neat amine/MS/ChCl mixtures and their samples after complete CO2 saturation. The effect of the mixture composition was studied by varying amine from primary (monoethanolamine, MEA) to secondary (diethanolamine, DEA) and tertiary (triethanolamine, TEA) amine, and the degree of its substitution from a mono- (MEA, DEA and TEA) to a doubly-substituted (ethylenediamine, EDA) compound. The role of an MS was investigated via the exchange of ethylene glycol (EG) with water and dimethylsulfoxide (DMSO). In addition, the influence of the CO2 absorption promoters present in the ternary MEA/EG/ChCl mixture at an amount of 5 wt. % was also investigated. We show that an increase in ρ and η in the amine/EG/ChCl mixture affects the properties of neat amines. This suggests that in the studied ternary mixtures, the nature of the interspecies interactions is very similar to those in the previously studied MEA/EG/ChCl system. When EG was exchanged for H2O or DMSO, a decrease in ρ and an increase in η were observed. A comparison of the data with the corresponding properties of the systems composed of each pair of the mixture components indicates that the intensity and/or number of interspecies interactions in the present ternary mixtures were stronger than those in pure H2O, DMSO and MEA. While in the presence of promoters no significant changes in the studied properties were found, for the corresponding CO2-saturated samples, the ρ and η increased proportionally to the amount of absorbed gas. This was also the case for all the systems studied in the present research. The overall CO2 absorption of the EG-based mixtures decreased when going from primary to secondary and tertiary amines; it was 21% higher for the MEA/H2O/ChCl system compared to the mixtures containing EG and DMSO, which, in turn, showed similar absorption capacities. When the promoters were added to the MEA/EG/ChCl mixture, the highest capacity was found for the piperazine-containing system.
Functionalized silica supports were synthesized under various conditions using tetraethoxysilane (TEOS) and silicon tetrachloride (STC) as precursors by the sol-gel method. The polyethylene glycol ...with a molecular weight of 1500 was used as a structure-controlling agent. The use of STC as a SiO
2
precursor allowed getting a higher specific surface area in comparison with TEOS. The influence of hydrothermal and acidic treatment on the specific surface area of the obtained structures was studied. The concentration of silanol groups was evaluated applying diffuse reflectance infrared Fourier transform spectroscopy. SEM micrographs showed that the use of toluene as an additional solvent of polyethylene glycol led to the formation of the agglomerates from sphere-shaped SiO
2
, meanwhile, the use of hexane led to the formation of a rhombohedral cell structure.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Bi-based perovskites (Bi2WO6, Bi2MoO6, BiFeO3, Bi4Ti3O12, etc.) have been documented as promising visible-light responsive materials for different photocatalytic applications (wastewater treatment, ...water splitting, CO2 reduction, and oxidation of hydrocarbons and alcohols to produce valuable chemicals). However, the main disadvantage of pure perovskites is the rapid recombination of photoinduced charge carriers and, therefore, low activity. Among different methods developed, creating heterojunctions, especially Z-scheme and S-scheme, is considered as the most effective approach to improve the photocatalytic performances of materials due to increased light absorption, improved separation of electrons-hole pairs, combination of different favorable properties of each component of a hybrid, possibility to use a wide range of semiconductors to construct an ideal composite. This critical review reports progress over the last 5 years in creating Z-scheme and S-scheme composites based on Bi-containing perovskites in photocatalysis for environmental remediation, hydrogen evolution, reduction of CO2 to CO and CH4, and production of industrially important organic chemicals by oxidation of hydrocarbons and alcohols. Moreover, challenges and opportunities are considered into developing new photocatalytic materials with their possible future commercialization. The critical review suggests strategies to improve the photocatalytic activity and stability of Z-scheme and S-scheme heterojunctions.
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•Recent progress in application of Bi-based perovskite photocatalysts is overviewed.•Creating Z/S-scheme heterojunctions is effective approach for improving activity.•Bi-based perovskite heterojunctions are promising for environmental applications.•Industrial-scale prospects for Bi-based Z/S-scheme heterojunctions are explored.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nanoparticles of Al, Mg, Ni, and Ti with an average size less than 50 nm were obtained directly from bulk samples by the inductive flow levitation (IFL) technique. The main advantages of this method ...are high productivity (up to 200 g/h of nanoparticles), control over the size of nanoparticles in a wide granulometric range (0.5–500 nm), and noncontact heating (up to 2500 °C), which determines the purity of the product and the compliance of the method with the basic principles of “green chemistry” (direct synthesis). The IFL method belongs to gas-phase technologies, a distinctive feature of which is metal evaporation in a suspended state (induction levitation) and noncontact heating. For the levitation of volumetric samples, seven types of induction coils were developed in the work in which the “temperature-levitation” properties were investigated. On the inductor of the fifth type, the modes of obtaining nanoparticles with different masses of the seed and the nature of the purge gas were tested. The resulting nanoparticles were thoroughly characterized by a wide range of physicochemical methods: transmission electron microscopy (TEM), high-resolution TEM, scanning electron microscopy–energy dispersive spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller, STSA, Barrett–Joyner–Halenda, dynamic light scattering, and inductively coupled plasma with mass spectrometry. In this work, it has been shown that the IFL method is one of the most promising methods for the synthesis of nanoparticles today, which allows to obtain NPs with a high degree of purity and homogeneity in one stage.
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IJS, KILJ, NUK, PNG, UL, UM
The current investigation is focused on the development of composite membranes based on polymeric ionic liquids (PILs) containing imidazolium and pyridinium polycations with various counterions, ...including hexafluorophosphate, tetrafluoroborate, and bis(trifluoromethylsulfonyl)imide. A combination of spectroscopic methods was used to identify the synthesized PILs and characterize their interaction with carbon dioxide. The density and surface free energy of polymers were performed by wettability measurements, and the results are in good agreement with the permeability and selectivity obtained within the gas transport tests. It was shown that the membranes with a selective layer based on PILs exhibit relatively high permeability with CO
and high ideal selectivity CO
/CH
and CO
/N
. Additionally, it was found that the type of an anion significantly affects the performance of the obtained membranes, with the most pronounced effect from bis-triflimide-based polymers, showing the highest permeability coefficient. These results provide valuable insights into the design and optimization of PIL-based membranes for natural and flue gas treatment.
Full text
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The current investigation is focused on the development of composite membranes based on polymeric ionic liquids (PILs) containing imidazolium and pyridinium polycations with various counterions, ...including hexafluorophosphate, tetrafluoroborate, and bis(trifluoromethylsulfonyl)imide. A combination of spectroscopic methods was used to identify the synthesized PILs and characterize their interaction with carbon dioxide. The density and surface free energy of polymers were performed by wettability measurements, and the results are in good agreement with the permeability and selectivity obtained within the gas transport tests. It was shown that the membranes with a selective layer based on PILs exhibit relatively high permeability with COsub.2 and high ideal selectivity COsub.2/CHsub.4 and COsub.2/Nsub.2. Additionally, it was found that the type of an anion significantly affects the performance of the obtained membranes, with the most pronounced effect from bis-triflimide-based polymers, showing the highest permeability coefficient. These results provide valuable insights into the design and optimization of PIL-based membranes for natural and flue gas treatment.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The present research provides data on the density (ρ), viscosity (η) and ability to absorb carbon dioxide of systems containing amine, molecular solvent (MS) and choline chloride (ChCl), with the ...investigation of the physical properties of both neat amine/MS/ChCl mixtures and their samples after complete COsub.2 saturation. The effect of the mixture composition was studied by varying amine from primary (monoethanolamine, MEA) to secondary (diethanolamine, DEA) and tertiary (triethanolamine, TEA) amine, and the degree of its substitution from a mono- (MEA, DEA and TEA) to a doubly-substituted (ethylenediamine, EDA) compound. The role of an MS was investigated via the exchange of ethylene glycol (EG) with water and dimethylsulfoxide (DMSO). In addition, the influence of the COsub.2 absorption promoters present in the ternary MEA/EG/ChCl mixture at an amount of 5 wt. % was also investigated. We show that an increase in ρ and η in the amine/EG/ChCl mixture affects the properties of neat amines. This suggests that in the studied ternary mixtures, the nature of the interspecies interactions is very similar to those in the previously studied MEA/EG/ChCl system. When EG was exchanged for Hsub.2 O or DMSO, a decrease in ρ and an increase in η were observed. A comparison of the data with the corresponding properties of the systems composed of each pair of the mixture components indicates that the intensity and/or number of interspecies interactions in the present ternary mixtures were stronger than those in pure Hsub.2 O, DMSO and MEA. While in the presence of promoters no significant changes in the studied properties were found, for the corresponding COsub.2 -saturated samples, the ρ and η increased proportionally to the amount of absorbed gas. This was also the case for all the systems studied in the present research. The overall COsub.2 absorption of the EG-based mixtures decreased when going from primary to secondary and tertiary amines; it was 21% higher for the MEA/Hsub.2 O/ChCl system compared to the mixtures containing EG and DMSO, which, in turn, showed similar absorption capacities. When the promoters were added to the MEA/EG/ChCl mixture, the highest capacity was found for the piperazine-containing system.
