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.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The present study continues the development and enhancement of a highly efficient unique hybrid technique-membrane-assisted gas absorption in designing the separation unit, which provides the ...improvement in mass-transfer of a target component during the ammonia capture process from a process loop of the Haber-Bosch technological route. In order to minimize the absorbent volume to membrane area ratio, the special separation cell was designed based on a combination of two types of hollow fiber membranes, dense gas separation membrane and porous pervaporation membrane. The separation performance tests were implemented under two sets of conditions, sweeping the bore (permeate) side of a cell with helium and hydrogen-nitrogen mix. For both cases, the membrane-assisted gas absorption cell demonstrated high separation efficiency, and the ammonia concentration in the permeate was never lower than 81 mol%; meanwhile, under the hydrogen-nitrogen bore sweep conditions, the ammonia concentration in the permeate reached 97.5 mol% in a single-step process. Nevertheless, there is a product purity-recovery rate trade-off, which is a typical issue for separation processes.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Display omitted
•Catalysts SILLPs type were obtained and functionalized with imidazole derivatives.•Maximum pore diameter of the samples was 15 nm with the mesoporous structure.•SILLPs based on ...4-Methyl Imidazole behave as more active catalyst.•The decrease in the desorption energy, inversely proportional to the activity.
The catalytic activity of imidazolium-based SILLPs stabilised onto DVB/CMS catalyst supports is evaluated to develop “Union Carbide” process catalytic systems. Under similar conditions, SILLPs based on 4-Methyl Imidazole behave as more active catalysts in trichlorosilane disproportionation in part of silane yield. In these systems, the polymer support is not only an inert matrix. The polymer is designed to play an important role. Firstly controlling the easy accessibility of the reagents to the active sites and providing specific micro-environments for a transition state complex. The structure of these supports can be tuned to adjust the catalytic efficiency SILLPs for different reactions. For this purpose, the meticulous physico-chemistry characterisation was carry out. Based on the experimental data obtained, a reaction mechanism is proposed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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.
Full text
Available for:
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.
Display omitted
•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.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Complex experimental study of membrane-assisted gas separation technique performed.•Trihexyltetradecylphosphonium indazolide synthesized and characterized.•Trihexyltetradecylphosphonium indazolide ...studied as a sorbent for CO2 and H2S.•The comparison of four ionic liquids is performed in a new hybrid process.
The present study deals with complex experimental evaluation of a unique hybrid technique – membrane-assisted gas absorption, which is proposed as an alternative approach to natural gas sweetening, and explores the ionic liquid with aprotic heterocyclic anion – trihexyltetradecylphosphonium indazolide as a component of the combined absorbent system. The synthesized ionic liquid was analyzed by 13C and 1H NMR in order to validate its formation and structure, afterwards the physicochemical properties, namely, density, viscosity, and absorption loading with respect to CH4, CO2 and H2S were determined, as well as the mass transfer properties of the combined membrane-absorbent system (permeability, diffusivity and sorption coefficients). The trihexyltetradecylphosphonium indazolide characterized by almost equimolar absorption loading for CO2 at elevated pressure, and the combined membrane-absorbent system provides selectivity up to 62 and 106.9 for the CH4/CO2 and CH4/H2S pairs respectively. Further, the efficiency of the proposed technique was evaluated experimentally on the example of separation of two binary CH4-based mixtures with CO2 and H2S as impurities. As a result of treatment, the purified product stream contains up to 93.34 and 99.998 vol% of CH4 in the case of CO2 and H2S removal, respectively.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The present study is concerned with a complex theoretical and experimental evaluation of the effect of various distribution coefficients on the hydrate crystallization process retrofitted ...with/without membrane in the process of the capture of carbon dioxide from flue gas (N2 (83.13 mol.%)/CO2 (16.87 mol.%)) at the low-pressure. A batch reactor with a stirrer was used to perform experiments under isothermal conditions of 275.5 K and initial pressure of 3.1 MPa, the aqueous solution with a TBAB concentration of 5.0 wt% in the presence of the 1500 ppm Tween-80 were tested. The following modes were studied: the pressure-dropping separation, separation at the constant pressure, and the continuous hydrate separation. The continuous hydrate separation with/without a membrane was modeled, and its experimental verification was carried out. It was shown that using a two-stage hydrate membrane technology with an increase in the distribution coefficient, the CO2 capture cost per ton decreased and could reach 35 $/ton, with a 92 % CO2 recovery and a CO2 residue flow of 0.4 mol.%.
Display omitted
•Hydrate crystallisation as an efficient method at CO2 recovery from flue gas.•Role of the membrane in a combined process of CO2 recovery from flue gas.•Maximum CO2 hydrate recovery is 92 % with purity 95 % based on the continuous hydrate-membrane separation.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Two new deep eutectic solvents (DESs) composed of urea (U) and salts of a choline family such as dimethyl-di(2-hydroxyethyl)-ammonium chloride Me2COH 2NCl and methyl-tri(2-hydroxyethyl)-ammonium ...chloride MeCOH 3NCl mixed in a 1:1 molar ratio were prepared. Their densities, viscosities, refractive indices, and properties related to the ammonia absorption were thoroughly investigated. We found that the obtained DESs show an absorption capacity of 2.078 and 2.632 molNH3·kg–1 DES for Me2COH 2NCl/U and MeCOH 3NCl/U, respectively, at 313.2 K and 101.3 kPa, which is approximately two times higher than for the choline chloride/urea (2:3) DES at the same conditions. Also, the obtained Henry’s law constants are of the same sequence; that is, they increase from MeCOH 3NCl/U to Me2COH 2NCl/U and finally to choline chloride/urea. The mentioned tendencies show good correlation with DES’s molar volume and its free volume, and also with the number of the CH2CH2OH substituents in a quaternary ammonium salt cation. This suggests that the gas capture occurs via the interactions (most likely H-bonding) between an NH3 molecule(s) and the hydroxyalkyl fragments. Indeed, the results of 1H NMR and FTIR spectroscopy confirm strong coupling between ammonia and hydroxyls leading to a distortion of the inherent DES structure. This finding agrees well with the fact that an NH3 dissolution process in the studied DESs is favored by an entropic contribution.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Over the past decade, mRNA-based therapy has displayed significant promise in a wide range of clinical applications. The most striking example of the leap in the development of mRNA technologies was ...the mass vaccination against COVID-19 during the pandemic. The emergence of large-scale technology and positive experience of mRNA immunization sparked the development of antiviral and anti-cancer mRNA vaccines as well as therapeutic mRNA agents for genetic and other diseases. To facilitate mRNA delivery, lipid nanoparticles (LNPs) have been successfully employed. However, the diverse use of mRNA therapeutic approaches requires the development of adaptable LNP delivery systems that can control the kinetics of mRNA uptake and expression in target cells. Here, we report effective mRNA delivery into cultured mammalian cells (HEK293T, HeLa, DC2.4) and living mouse muscle tissues by liposomes containing either 1,26-bis(cholest-5-en-3β-yloxycarbonylamino)-7,11,16,20-tetraazahexacosane tetrahydrochloride (2X3) or the newly applied 1,30-bis(cholest-5-en-3β-yloxycarbonylamino)-9,13,18,22-tetraaza-3,6,25,28-tetraoxatriacontane tetrahydrochloride (2X7) cationic lipids. Using end-point and real-time monitoring of Fluc mRNA expression, we showed that these LNPs exhibited an unusually delayed (of over 10 h in the case of the 2X7-based system) but had highly efficient and prolonged reporter activity in cells. Accordingly, both LNP formulations decorated with 1,2-distearoyl-
-glycero-3-phosphoethanolamine-
-amino(polyethylene glycol)-2000 (DSPE-PEG
) provided efficient luciferase production in mice, peaking on day 3 after intramuscular injection. Notably, the bioluminescence was observed only at the site of injection in caudal thigh muscles, thereby demonstrating local expression of the model gene of interest. The developed mRNA delivery systems hold promise for prophylactic applications, where sustained synthesis of defensive proteins is required, and open doors to new possibilities in mRNA-based therapies.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
