Synthesis of Zinc Nanoparticles by the Gas Condensation Method in a Non-Contact Crucible and Their Physical-Chemical Characterization.

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 Influence of Polycation and Counter-Anion Nature on the Properties of Poly(ionic liquid)-Based Membranes for CO2 Separation.

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.

Membrane Cascade Type of «Continuous Membrane Column¼ for Power Plant Post-Combustion Carbon Dioxide Capture Part 1: Simulation of the Binary Gas Mixture Separation.

The present paper deals with the complex study of CO2 capture from combined heat power plant flue gases using the efficient technological design of a membrane cascade type of «Continuous Membrane Column¼ for binary gas mixture separation. In contrast to well-known multi-step or multi-stage process designs, the cascade type of separation unit provides several advantages. Here, the separation process is implemented in it by creating two counter current flows. In one of them is depleted by the high-permeable component in a continuous mode, meanwhile the other one is enriched. Taking into account that the circulating flows rate overcomes the withdrawn one, there is a multiplicative increase in separation efficiency. A comprehensive study of CO2 capture using the membrane cascade type of «Continuous Membrane Column¼ includes the determination of the optimal membrane material characteristics, the sensitivity study of the process, and a feasibility evaluation. It was clearly demonstrated that the proposed process achieves efficient CO2 capture, which meets the modern requirements in terms of the CO2 content (≥95 mol.%), recovery rate (≥90%), and residual CO2 concentration (≤2 mol.%). Moreover, it was observed that it is possible to process CO2 with a purity of up to 99.8 mol.% at the same recovery rate. This enables the use of this specific process design in CO2 pretreatment operations for the production of high-purity carbon dioxide.

The Cation Effect on the Free Volume and the Solubility of H2S and CO2 in Ionic Liquids Based on Bis(2-Ethylhexyl) Sulfosuccinate Anion.

Herein, we report for the first time a study dedicated to acidic gases' solubility in ionic liquids with sterically hindered bulky anion, namely bis(2-ethylhexyl) sulfosuccinate ([doc]), experimentally evaluated at low pressures. The effect of cation change (imidazolium, pyridinium, and pyrrolidinium) on the thermophysical properties and sorption capacities was also discussed. The densities and the activation energies of the tested ILs exhibited minor differences. Furthermore, the COSMO-RS model was used to predict the free volumes of ILs aiming to investigate its influence on gas solubilities. The conducted calculations have revealed an antibate correlation between the fractional free volume (FFV) and Henry's law constant. In particular, the lowest FFV in 1-methylimidazolium [doc] corresponded to the minimal sorption and vice versa. In addition, it was shown that the presence of protic cation results in a significant reduction in CO2 and H2S solubilities. In general, the solubility measurement results of the synthesized ILs have shown their superiority compared to fluorinated ILs based on the physical absorption mechanism.

Bifunctional Silica-Supported Ionic Liquid Phase (SILP) Catalysts in Silane Production: Their Synthesis, Characterization and Catalytic Activity.

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.

An Efficient Technique for Ammonia Capture in the Haber-Bosch Process Loop-Membrane-Assisted Gas Absorption.

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.

Acidic Gases Solubility in Bis(2-Ethylhexyl) Sulfosuccinate Based Ionic Liquids Using the Predictive Thermodynamic Model.

To properly design ionic liquids (ILs) adopted for gases separation uses, a knowledge of ILs thermodynamic properties as well their solubilities with the gases is essential. In the present article, solubilities of CO2 and H2S in bis(2-Ethylhexyl)sulfosuccinate based ILs were predicted using the conductor like screening model for real solvents COSMO-RS. According to COSMO-RS calculations, the influence of the cation change was extensively analyzed. The obtained data are used for the prediction of adequate solvent candidates. Moreover, to understand the intrinsic behavior of gases solubility the free volume of the chosen ILs and their molecular interactions with respectively CO2 and H2S were computed. The results suggest that hydrogen bonding interactions in ILs and between ILs and the gases have a pivotal influence on the solubility.

Towards the interaction between calcium carbide and water during gas-chromatographic determination of trace moisture in ultra-high purity ammonia.

The current study focuses on the processes involved during the flow conversion of water into acetylene in a calcium carbide reaction cell for the trace moisture analysis of ammonia by reaction gas chromatography. The factors negatively affecting the reproducibility and the accuracy of the measurements are suggested and discussed. The intramolecular reaction of the HOCaCCH intermediate was found to be a side reaction producing background acetylene during the contact of wet ammonia gas with calcium carbide. The presence of the HOCaCCH intermediate among the reaction products is confirmed by an FTIR spectral study of calcium carbide powder exposed to wet gas. The side reaction kinetics is evaluated experimentally and its influence on the results of the gas chromatographic measurements is discussed in relation to the determination of the optimal operating parameters for ammonia analysis. The reaction gas chromatography method for the trace moisture measurements in an ammonia matrix was experimentally compared to an FTIR long-path length gas cell technique to evaluate the accuracy limitations and the resource intensity.

Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO2 Separation from CH4 and N2.

CO2 separation was found to be facilitated by transport membranes based on novel chitosan (CS)-poly(styrene) (PS) and chitosan (CS)-poly(acrylonitrile) (PAN) copolymer matrices doped with methylimidazolium based ionic liquids: [bmim][BF4], [bmim][PF6], and [bmim][Tf2N] (IL). CS plays the role of biodegradable film former and selectivity promoter. Copolymers were prepared implementing the latest achievements in radical copolymerization with chosen monomers, which enabled the achievement of outstanding mechanical strength values for the CS-based membranes (75-104 MPa for CS-PAN and 69-75 MPa for CS-PS). Ionic liquid (IL) doping affected the surface and mechanical properties of the membranes as well as the gas separation properties. The highest CO2 permeability 400 Barrers belongs to CS-b-PS/[bmim][BF4]. The highest selectivity α (CO2/N2) = 15.5 was achieved for CS-b-PAN/[bmim][BF4]. The operational temperature of the membranes is under 220 °C.

The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes.

Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N2, NH3, H2S, and CO2 gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF6] and [emim][Tf2N]. The modification of SILMs by nanosize silica particles leads to an increase of NH3 separation relatively to CO2 or H2S.