scholarly journals Removal of Siloxanes from Model Biogas by Means of Deep Eutectic Solvents in Absorption Process

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 241
Author(s):  
Edyta Słupek ◽  
Patrycja Makoś-Chełstowska ◽  
Jacek Gębicki
Keyword(s):  
Experimental Studies ◽  
Deep Eutectic Solvents ◽  
Molar Ratio ◽  
Tetraethylene Glycol ◽  
Absorption Process ◽  
Molar Ratios ◽  
Screening Model ◽  
Tetrapropylammonium Bromide ◽  
Ft Ir ◽  
Ir Analysis

The paper presents the screening of 20 deep eutectic solvents (DESs) composed of tetrapropylammonium bromide (TPABr) and glycols in various molar ratios, and 6 conventional solvents as absorbents for removal of siloxanes from model biogas stream. The screening was achieved using the conductor-like screening model for real solvents (COSMO-RS) based on the comparison of siloxane solubility in DESs. For the DES which was characterized by the highest solubility of siloxanes, studies of physicochemical properties, i.e., viscosity, density, and melting point, were performed. DES composed of tetrapropylammonium bromide (TPABr) and tetraethylene glycol (TEG) in a 1:3 molar ratio was used as an absorbent in experimental studies in which several parameters were optimized, i.e., the temperature, absorbent volume, and model biogas flow rate. The mechanism of siloxanes removal was evaluated by means of an experimental FT-IR analysis as well as by theoretical studies based on σ-profile and σ-potential. On the basis of the obtained results, it can be concluded that TPABr:TEG (1:3) is a very effective absorption solvent for the removal of siloxanes from model biogas, and the main driving force of the absorption process is the formation of the hydrogen bonds between DES and siloxanes.

scholarly journals TWO-STEP CROSSLINKING OF PVP/GEL NANOFIBERS

2021 ◽  
Vol 2021 ◽  
pp. 164-170
Author(s):  
H.K. Güler ◽  
F.C. Çallıoğlu
Keyword(s):  
Fiber Diameter ◽  
Experimental Studies ◽  
Water Soluble ◽  
Diameter Distribution ◽  
Sem Images ◽  
Crosslinking Process ◽  
Different Temperatures ◽  
Ft Ir ◽  
Ir Analysis ◽  
Gel Polymers

In this study, it was achieved that crosslinking of PVP/GEL nanofibers with two-steps. Crosslinking is a process highly important for water-soluble polymers in terms of application areas and mechanical properties. Firstly, crosslinking of PVP polymers experimental studies were carried out via heat treatment at different temperatures and times. Then, GEL polymers were crosslinked with GTA vapour at different times. Morphological analysis was carried out via SEM images and chemical characteristics were determined via FT-IR analysis. Moreover, after the crosslinking process, SD and WL values were calculated. All results showed that before crosslinking of SEM images, nanofibers were smooth, fine and without beads. The average fiber diameter is 196 nm and the fiber diameter distribution is quite uniform. After crosslinking of SEM images, it is expected that all nanowebs will turn from fibrous surfaces to membranous. Generally, SD and WL values decrease with crosslinking time increase. According to all of the SEM images, SD and WL values, optimum conditions were determined for PVP as 4 hours at 180oC and for GEL as 24 hours. Lastly, the presence of PVP and GEL polymers in the nanofiber structure was verified chemically with FT-IR analysis.

scholarly journals Theoretical and Economic Evaluation of Low-Cost Deep Eutectic Solvents for Effective Biogas Upgrading to Bio-Methane

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3379
Author(s):  
Edyta Słupek ◽  
Patrycja Makoś ◽  
Jacek Gębicki
Keyword(s):  
Economic Evaluation ◽  
Excess Enthalpy ◽  
Low Cost ◽  
Choline Chloride ◽  
Unit Cost ◽  
Deep Eutectic Solvents ◽  
Molar Ratio ◽  
Biogas Upgrading ◽  
Screening Model ◽  
Effective Removal

This paper presents the theoretical screening of 23 low-cost deep eutectic solvents (DESs) as absorbents for effective removal of the main impurities from biogas streams using a conductor-like screening model for real solvents (COSMO-RS). Based on thermodynamic parameters, i.e., the activity coefficient, excess enthalpy, and Henry’s constant, two DESs composed of choline chloride: urea in a 1:2 molar ratio (ChCl:U 1:2), and choline chloride: oxalic acid in a 1:2 molar ratio (ChCl:OA 1:2) were selected as the most effective absorbents. The σ-profile and σ-potential were used in order to explain the mechanism of the absorptive removal of CO2, H2S, and siloxanes from a biogas stream. In addition, an economic analysis was prepared to demonstrate the competitiveness of new DESs in the sorbents market. The unit cost of 1 m3 of pure bio-methane was estimated to be in the range of 0.35–0.37 EUR, which is comparable to currently used technologies.

scholarly journals Silica Gel Impregnated by Deep Eutectic Solvents for Adsorptive Removal of BTEX from Gas Streams

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1894 ◽  
Author(s):  
Patrycja Makoś ◽  
Edyta Słupek ◽  
Aleksandra Małachowska
Keyword(s):  
Lactic Acid ◽  
Silica Gel ◽  
Choline Chloride ◽  
Specific Interaction ◽  
Chemical Properties ◽  
Deep Eutectic Solvents ◽  
Molar Ratio ◽  
Gas Streams ◽  
Tetrapropylammonium Bromide ◽  
Sorbent Materials

The paper presents the preparation of new adsorbents based on silica gel (SiO2) impregnated with deep eutectic solvents (DESs) to increase benzene, toluene, ethylbenzene, and p-xylene (BTEX) adsorption efficiency from gas streams. The DESs were synthesized by means of choline chloride, tetrapropylammonium bromide, levulinic acid, lactic acid, and phenol. The physico-chemical properties of new sorbent materials, including surface morphology and structures, as well as porosity, were studied by means of thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and Brunauer–Emmett–Teller analysis. The effect of DESs type, flow rate, and initial concentration of BTEX were also investigated followed by regeneration and reusability of adsorbents. The results indicate that SiO2 impregnated with tetrapropylammonium bromide and lactic acid in a 1:2 molar ratio have great potential for the removal of BTEX from gas streams. Its adsorption capacity was higher than the pure SiO2 and other developed SiO2-DES adsorbents. This result can be explained by the specific interaction between DESs and BTEX, i.e., hydrogen bonds interaction.

Investigation on Properties of Magnesia Grinding Wheels Used in Silicon Wafer Grinding

2014 ◽  
Vol 1017 ◽  
pp. 273-278
Author(s):  
Bing Jun Hao ◽  
Zhi Gang Dong ◽  
Shang Gao ◽  
Ren Ke Kang ◽  
Dong Ming Guo
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Integrated Assessment ◽  
Experimental Studies ◽  
Molar Ratio ◽  
Rockwell Hardness ◽  
Grinding Wheels ◽  
Curing Conditions ◽  
Molar Ratios ◽  
Scanning Electron

This paper presents the results of an experimental investigation on molar ratios of MgO/ MgCl2 affecting the hardness of magnesia grinding wheels, which is one of the most important properties. Magnesite grinding blocks of different ratios of MgO/MgCl2 were prepared. The surface Rockwell hardness of which was tested under the same curing conditions. By an integrated assessment of the experimental studies of hardness and component, it is recognized that the molar ratios of MgO/MgCl2 can significantly affect the properties of magnesia grinding wheels. With the increase of MgO/MgCl2 molar ratio, hardness of the specimens increases. Scanning electron microscopy (SEM) studies on grinding blocks of different ratios indicated that micro needle shaped crystal structure of phase 5 are mainly responsible for hardness development. Finally the optimal recipe was selected in consideration of the characteristics of the silicon mechanical chemical grinding (MCG), which was verified to be effective by the following grinding experiment.

Synthesis and Characterisation of P-perfluoro{-1-[2-(2-fluorosulfonylethoxy) Propoxy]}Ethylated Polystyrene

2005 ◽  
Vol 2005 (8) ◽  
pp. 546-548
Author(s):  
Ji-Cheng Yang ◽  
Hong-Bo Ni ◽  
Jin Li ◽  
Cheng-Xue Zhao ◽  
Yong-Ming Zhang
Keyword(s):  
Thermogravimetric Analysis ◽  
Contact Angles ◽  
Molar Ratio ◽  
Ethyl Group ◽  
Molar Ratios ◽  
Modified Polymer ◽  
Ft Ir

A new kind of fluorinated polystyrene bearing a p-perfluoro{-1-[2-(2-fluorosulfonyl)propoxy]}ethyl group has been synthesised by one-electron oxidation of polystyrene by perfluoro{2-[2-(2-fluorosulfonyl) propoxy]}propionyl peroxide at different peroxide to polystyrene molar ratios. The yield of ω–fluorosulfonyl perfluoroalkylation decreases with increase in the reactant molar ratio. The modified polymer was characterised by various techniques: the ring perfluoro{-1-[2-(2-fluorosulfonyl)propoxy]}ethylation was proved by FT-IR, 19F NMR and DSC; desulfonylation of the fluorinated polystyrene appearing at 126° has been found by thermogravimetric analysis (TGA). The contact angles of water on the surface of ω–fluorosulfonyl perfluoroalkylated polystyrene were determined.

Synthesis, characterization and enzymatic degradation of copolymers of ε-caprolactone and hydroxy-fatty acids

2016 ◽  
Vol 88 (12) ◽  
pp. 1191-1201 ◽  
Author(s):  
Diana Aparaschivei ◽  
Anamaria Todea ◽  
Iulia Păuşescu ◽  
Valentin Badea ◽  
Mihai Medeleanu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Degradation Products ◽  
Hydroxy Fatty Acids ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Chemical Structures ◽  
Buffer Solutions ◽  
Different Temperatures ◽  
Ft Ir ◽  
Candida Antarctica B

AbstractNew copolymers of ε-caprolactone with three hydroxy-fatty acids, 12-hydroxy stearic acid, 16-hydroxyhexadecanoic acid and ricinoleic acid, were synthesized by catalytic polyesterification. The reactions were carried out in solvent-free systems and in organic solvents as well, using tin(II) 2-ethylhexanoate as catalyst, at different temperatures and molar ratios of the comonomers. Cyclic and linear polymeric products with medium molar weight of about 2000 Da have been synthesized and their chemical structures were confirmed by FT-IR, NMR and MALDI-TOF MS analysis. The synthesis parameters were optimized and the ε-caprolactone/hydroxy acid molar ratio was set as 5:1, according to mass spectrometry results. The biodegradability of the newly synthesized polymers was studied in the presence of Candida antarctica B lipase in phosphate buffer solutions (pH=7.4), at 37°C. The weight-loss profile emphasized the degradation of the 16-hydroxyhexadecanoic acid based polymer samples at more than 50% of their initial weight in 18 days of incubation in the presence of the lipase. The composition of the degradation products was assessed using the GC-MS technique and displayed residues of the comonomers moieties.

scholarly journals Exopolysaccharide from Lactobacillus helveticus: identification of chemical structure and effect on biscuit duality

2010 ◽  
Vol 28 (No. 3) ◽  
pp. 225-232 ◽  
Author(s):  
A.S. Hussein ◽  
G.S. Ibrahim ◽  
M.M.S. Asker ◽  
M.G. Mahmoud
Keyword(s):  
Gel Permeation Chromatography ◽  
Lactobacillus Helveticus ◽  
Molar Ratio ◽  
Composition Analysis ◽  
Molecular Weights ◽  
Ft Ir ◽  
Ir Analysis ◽  
Dough Development Time ◽  
Addition Level ◽  
Different Levels

Exopolysaccharide (LB-gum) was produced from Lactobacillus helveticus by ethanol precipitation and gel-permeation chromatography. The structures of LB1 and LB2 were estimated by sugar composition analysis, methylation, and FT-IR analysis. The results proved the contents of glucose and galactose in molar ratio of 2:1 and 2.3:1, and molecular weights ~5.4 &times; 10<sup>5</sup> Da and ~20.3 &times; 10<sup>5</sup> Da, respectively. Xanthan and LB-gum were added to wheat flour during biscuits making at levels of 0, 0.5, 1.0, 1.5, and 2.0%. Rheological properties and chemical quality attributes of the biscuits during storage for six months were evaluated. The data revealed slight increases in water absorption, dough development time, and dough stability but weakening decreased about 50 %. Also, height, weight, volume, and specific volume were found to increase as xanthan and LB-gum level increased. The colour was slightly affected. There were no significant differences between the samples containing xanthan and LB-gum at different levels with respect to all parameters tested except for the taste. Shelf &ndash; life of biscuit prolonged as a result of xanthan or LB-gum addition. The best addition level to improve the biscuits quality was 1.0% of xanthan or 1.5% of LB-gum. &nbsp;

Synthesis and Characterization of Dumbbell Shaped Calcium Carbonate Induced by Lignin

2010 ◽  
Vol 658 ◽  
pp. 49-52 ◽  
Author(s):  
Wen Kun Zhu ◽  
Xue Gang Luo ◽  
An Kai Luo ◽  
Xuan Liang
Keyword(s):  
Infrared Spectroscopy ◽  
Calcium Carbonate ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Synthesis Mechanism ◽  
Ft Ir ◽  
Ir Analysis ◽  
Decomposition Behavior ◽  
Normal Calcium

Calcium carbonate with various structures and morphologies were prepared under double injection of the CaCl2 and Na2CO3 solutions with molar ratio of 1:1 at 30 °C, taking lignin as the induction agents. They were characterized by scanning electron microscopy, infrared spectroscopy thermal analysis and X-ray diffraction. The synthesis mechanism was also discussed. The results showed that calcium carbonate of different shape were obtained with the concentration of lignin at 10g/L, 20g/L and 30g/L, respectively, under 30°C while CaCl2 and Na2CO3 were kept at the same concentration of 0.5mol/L. The size of the particles was in a range between 3 and 5μm and the particles were calcites. Compared with the normal calcium carbonate, the compound has advanced thermal decomposition behavior. Fourier transform infrared spectroscopy (FT-IR) analysis revealed the presence of lignin and calcite. The electrostatic interaction of Ca2+ with lignin and the complementary of stereo-structure play important roles in the formation of Dumbbell Shaped Calcium Carbonate.

scholarly journals New Carvone-Based Deep Eutectic Solvents for Siloxanes Capture from Biogas

2021 ◽  
Vol 22 (17) ◽  
pp. 9551
Author(s):  
Patrycja Makoś-Chełstowska ◽  
Edyta Słupek ◽  
Aleksandra Kramarz ◽  
Jacek Gębicki
Keyword(s):  
Experimental Studies ◽  
Deep Eutectic Solvents ◽  
Absorption Capacity ◽  
Theoretical Studies ◽  
New Methods ◽  
Physical Absorption ◽  
Ft Ir ◽  
The Individual ◽  
Engine Components ◽  
High Absorption

During biogas combustion, siloxanes form deposits of SiO2 on engine components, thus shortening the lifespan of the installation. Therefore, the development of new methods for the purification of biogas is receiving increasing attention. One of the most effective methods is physical absorption with the use of appropriate solvents. According to the principles of green engineering, solvents should be biodegradable, non-toxic, and have a high absorption capacity. Deep eutectic solvents (DES) possess such characteristics. In the literature, due to the very large number of DES combinations, conductor-like screening models for real solvents (COSMO-RS), based on the comparison of siloxane activity coefficient of 90 DESs of various types, were studied. DESs, which have the highest affinity to siloxanes, were synthesized. The most important physicochemical properties of DESs were carefully studied. In order to explain of the mechanism of DES formation, and the interaction between DES and siloxanes, the theoretical studies based on σ-profiles, and experimental studies including the 1H NMR, 13C NMR, and FT-IR spectra, were applied. The obtained results indicated that the new DESs, which were composed of carvone and carboxylic acids, were characterized by the highest affinity to siloxanes. It was shown that the hydrogen bonds between the active ketone group (=O) and the carboxyl group (-COOH) determined the formation of stable DESs with a melting point much lower than those of the individual components. On the other hand, non-bonded interactions mainly determined the effective capture of siloxanes with DES.

Synthesis of Nanosized TiO2-SiO2 Particles in Microemulsions Stabilized by Anionic Surfactants

2011 ◽  
Vol 695 ◽  
pp. 602-605
Author(s):  
Man Sig Lee ◽  
Ju Dong Lee ◽  
Hong Dae Kim ◽  
Seong Soo Hong
Keyword(s):  
Anionic Surfactants ◽  
Anatase Phase ◽  
Silica Content ◽  
Molar Ratio ◽  
Titanium Tetraisopropoxide ◽  
Xrd Pattern ◽  
Ft Ir ◽  
Ir Analysis ◽  
Hydrolysis Of ◽  
Controlled Hydrolysis

Nanosized TiO2-SiO2 particles were prepared by controlled hydrolysis of titanium tetraisopropoxide (TTIP) and tetraethylorthosilicate (TEOS) in microemulsions stabilized by anionic surfactants. Anionic surfactants ammonium carboxylate perfluoropolyether (PFPE-NH4) and sodium bis (2-ethylhexyl) sulfosuccinate (AOT) were used for formation of stabilized microemulsions in the W/C and W/O systems, respectively. The physical properties of the prepared particles have been investigated by TG-DTA, FT-IR, XRD and HRTEM. It is shown that the XRD pattern of the TiO2-SiO2 particles dried at 105 °C without calcination indicates amorphous. The particles calcined at 500 °C were identified as nanocrystalline anatase regardless of TTIP/TEOS molar ratio. The crystallite size of prepared particles decreased with increasing the silica content. From FT-IR analysis, the band for Ti-O-Si vibration was observed. The micrographs of HRTEM shown that the TiO2-SiO2 nanoparticles have a spherical morphology with a narrow size distribution and then the lattice fringe was 3.5 Å, which corresponds to the lattice spacing of (101) plane in the anatase phase.

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