scholarly journals High Efficiency Gas Permeability Membranes from Ethyl Cellulose Grafted with Ionic Liquids

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1900 ◽  
Author(s):  
Jingyu Xu ◽  
Hongge Jia ◽  
Nan Yang ◽  
Qingji Wang ◽  
Guoxing Yang ◽  
...  

Ethyl cellulose was grafted with ionic liquids in optimal yields (62.5–64.1%) and grafting degrees (5.93–7.90%) by the esterification of the hydroxyl groups in ethyl cellulose with the carboxyl groups in ionic liquids. In IR spectra of the ethyl cellulose derivatives exhibited C=O bond stretching vibration peaks at 1760 or 1740 cm−1, confirming the formation of the ester groups and furnishing the evidence of the successful grafting of ethyl cellulose with ionic liquids. The ethyl cellulose grafted with ionic liquids could be formed into membranes by using the casting solution method. The resulting membranes exhibited good membrane forming ability and mechanical properties. The EC grafted with ionic liquids-based membranes demonstrated PCO2/PCH4 separation factors of up to 18.8, whereas the PCO2/PCH4 separation factor of 9.0 was obtained for pure EC membrane (both for CO2/CH4 mixture gas). The membranes also demonstrated an excellent gas permeability coefficient PCO2, up to 199 Barrer, which was higher than pure EC (PCO2 = 46.8 Barrer). Therefore, it can be concluded that the ionic liquids with imidazole groups are immensely useful for improving the gas separation performances of EC membranes.

2019 ◽  
Vol 22 (2) ◽  
pp. 228-234 ◽  
Author(s):  
Ut Dong THACH ◽  
Thi Lan Nhi Do ◽  
Ngoc Lan Anh Do ◽  
Minh Huy Do

Introduction: Ionic liquids (ILs) have attached many attentions due to their interesting physicochemical properties. However, ionic liquids have several disadvantages including high viscosity, difficult to purify, separate and recycle, and expensive. Therefore, supported ionic liquids (SIL) have been developed to overcome these problems. SIL based on cellulose material was conventionally synthesized by silanization reaction between ionic liquid trialkoxyl silane and hydroxyl groups on the surface of cellulose. However, low reactivity of cellulose hydroxyl groups causes the low efficiency of silanization reaction. With the aim to resolve these problems and improve the reactivity of cellulose silanization reaction, cellulose graft ionic liquid was synthesized and characterized. Methods: Cellulose graft ionic liquid (CL-IL) material was synthesized by silanization reaction. The influence of reaction condition such as IL/CL (w/w) ratio, base catalyst (NH3) and agent coupling tetraethyl orthosilicate (TEOS) on silanization reaction was investigated. The modified CL-IL materials were characterized using FT-IR, TGA, SEM. The ion exchange properties were evaluated via batch adsorption studies to evidence the efficiency of silanization reaction of cellulose. Results: The study indicated that adding TEOS with NH3 catalyst could significantly increase the number of imidazolium groups grafted on cellulose about 75% compared to the conventional approach. CL-IL material is an efficient anion exchange materials displaying fast kinetic adsorption and high capacity adsorption of MO up to 1.4 mmol g-1. Conclusion: High-efficiency of cellulose silanization was obtained by using coupling agent TEOS and base catalyst. Therefore, the silanization reaction can be used for synthesis divers of functional cellulose materials. This approach can be aimed for the design of cheaper and high-performance materials for catalysis, polymer composite and adsorption in water treatment and depollution of industrial wastewater.  


Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4158
Author(s):  
Patrycja Glińska ◽  
Andrzej Wolan ◽  
Wojciech Kujawski ◽  
Edyta Rynkowska ◽  
Joanna Kujawa

There has been an ongoing need to develop polymer materials with increased performance as proton exchange membranes (PEMs) for middle- and high-temperature fuel cells. Poly(vinyl alcohol) (PVA) is a highly hydrophilic and chemically stable polymer bearing hydroxyl groups, which can be further altered. Protic ionic liquids (proticILs) have been found to be an effective modifying polymer agent used as a proton carrier providing PEMs’ desirable proton conductivity at high temperatures and under anhydrous conditions. In this study, the novel synthesis route of PVA grafted with fluorinated protic ionic liquids bearing sulfo groups (–SO3H) was elaborated. The polymer functionalization with fluorinated proticILs was achieved by the following approaches: (i) the PVA acylation and subsequent reaction with fluorinated sultones and (ii) free-radical polymerization reaction of vinyl acetate derivatives modified with 1-methylimidazole and sultones. These modifications resulted in the PVA being chemically modified with ionic liquids of protic character. The successfully grafted PVA has been characterized using 1H, 19F, and 13C-NMR and FTIR-ATR. The presented synthesis route is a novel approach to PVA functionalization with imidazole-based fluorinated ionic liquids with sulfo groups.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yuanli Chen ◽  
Hui Fan ◽  
Xinlin Zha ◽  
Wenwen Wang ◽  
Yi Wu ◽  
...  

AbstractHigh efficiency and anti-pollution oil/water separation membrane has been widely explored and researched. There are a large number of hydroxyl groups on the surface of silica, which has good wettability and can be used for oil-water separation membranes. Hydrophilic silica nanostructures with different morphologies were synthesized by changing templates and contents of trimethylbenzene (TMB). Here, silica nanospheres with radical pores, hollow silica nanospheres and worm-like silica nanotubes were separately sprayed on the PVA-co-PE nanofiber membrane (PM). The abundance of hydroxyl groups and porous structures on PM surfaces enabled the absorption of silica nanospheres through hydrogen bonds. Compared with different silica nanostructures, it was found that the silica/PM exhibited excellent super-hydrophilicity in air and underwater “oil-hating” properties. The PM was mass-produced in our lab through melt-extrusion-phase-separation technique. Therefore, the obtained membranes not only have excellent underwater superoleophobicity but also have a low-cost production. The prepared silica/PM composites were used to separate n-hexane/water, silicone oil/water and peanut oil water mixtures via filtration. As a result, they all exhibited efficient separation of oil/water mixture through gravity-driven filtration.


2020 ◽  
Vol 92 (10) ◽  
pp. 1717-1731
Author(s):  
Yucui Hou ◽  
Zhi Feng ◽  
Jaime Ruben Sossa Cuellar ◽  
Weize Wu

AbstractPhenolic compounds are important basic materials for the organic chemical industry, such as pesticides, medicines and preservatives. Phenolic compounds can be obtained from biomass, coal and petroleum via pyrolysis and liquefaction, but they are mixtures in oil. The traditional methods to separate phenols from oil using alkaline washing are not environmentally benign. To solve the problems, deep eutectic solvents (DESs) and ionic liquids (ILs) have been developed to separate phenols from oil, which shows high efficiency and environmental friendliness. In this article, we summarized the properties of DESs and ILs and the applications of DESs and ILs in the separation of phenols and oil. There are two ways in which DESs and ILs are used in these applications: (1) DESs formed in situ using different hydrogen bonding acceptors including quaternary ammonium salts, zwitterions, imidazoles and amides; (2) DESs and ILs used as extractants. The effect of water on the separation, mass transfer dynamics in the separation process, removal of neutral oil entrained in DESs, phase diagrams of phenol + oil + extractant during extraction, are also discussed. In the last, we analyze general trends for the separation and evaluate the problematic or challenging aspects in the separation of phenols from oil mixtures.


2020 ◽  
Vol 61 (2) ◽  
pp. 29-36
Author(s):  
Zoya P. Belousova ◽  

Bacterial cellulose obtained by culturing Gluconacetobacter sucrofermentans in HS environment was converted to sulfonate derivatives using methane-, toluene- and 2-phthalimidoethanesulfonic acids in pyridine. When the ratio of the starting reagents is 1 : 1, the modification of bacterial cellulose according to the primary hydroxyl group of glucopyranose fragments is most likely. The formation of 6-substituted bacterial cellulose derivatives was observed in the reaction mixture. The IR spectra of the reaction products contain absorption bands, which are specific for (O–SO2) group in the region 1377-1338 cm−1 (as), 1178-1154 cm−1 (s), fragments of the corresponding sulfonic acids, as well as free hydroxyl groups of glucopyranose in the region 3495-3382 cm−1. Bacterial cellulose 2-phthalimidoethanesulfonate was dissolved in pyridine. After drying with a desiccant in a desiccator, it turned into a dense transparent film of brown color. The increased molecular film allows to explain the side reaction occurring between the oxo group and fragments of one of the chains of modified cellulose and the non-substituted hydroxymethyl group. The IR spectrum of bacterial cellulose 6-(2-phthalimidoethanesulfonate) contains absorption bands in the region 1711 cm−1, which are specific for (Ar–CO–O) group, and absorption bands in the region 1618 cm−1, which prove the presence of (CO–NH) group. In order to impart antibiotic properties to the bacterial cellulose 6-(2-phthalimido-ethanesulfonate) film, it was physically modified with clotrimazole. The obtained experimental data showed that the films subjected to treatment with a 1% solution of clotrimazole have antibacterial and antifungal effects and prevent the growth of pathogenic microbiota on the wound surface. The exit rates of clotrimazole from the bacterial cellulose 6-(2-phthalimidoethanesulfonate) film and from the pure bacterial cellulose film differed, but only slightly. 2-Phthalimidoethanesulfonate bacterial cellulose films can be used to form composites of effective wound covering, since in addition to the unique properties of bacterial cellulose itself (low allergenicity and adhesion to the wound surface, high hygroscopicity) they will have a regenerating effect.


2019 ◽  
Author(s):  
Chen Chen ◽  
Aydin Ozcan ◽  
A. Ozgur Yazaydin ◽  
Bradley Ladewig

<b>Abstract</b><div>Grain boundaries are an unavoidable microstructural feature in intergrown polycrystalline metal-organic framework (MOF) membranes. They have been suspected to be less size-selective than a MOF’s micropores, resulting in suboptimal separation performances – a speculation recently confirmed by transmission electron microscopy of MOF ZIF-8. Single-crystal membranes, without grain boundaries, should confine mass transport to micropores and reflect the intrinsic selectivity of the porous material. Here, we demonstrate the feasibility of fabricating single-crystal MOF membranes and directly measuring gas permeability through such a membrane using ZIF-8 as an exemplary MOF. Our single-crystal ZIF-8 membranes achieved ideal selectivities up to 28.9, 10.0, 40.1 and 3.6 for gas pairs CO<sub>2</sub>/N<sub>2</sub>, CO<sub>2</sub>/CH<sub>4</sub>, He/CH<sub>4</sub> and CH<sub>4</sub>/N<sub>2</sub> respectively, much higher than or reversely selective to over 20 polycrystalline ZIF-8 membranes, unequivocally proving the non-selectivity of grain boundaries. The permeability trend obtained in single-crystal membranes aligned with a force field that had been validated against multiple empirical adsorption isotherms.<br></div>


2010 ◽  
Vol 178 ◽  
pp. 300-307 ◽  
Author(s):  
Jun Sheng Yuan ◽  
Fei Li ◽  
Hui Ru Han ◽  
Zhi Yong Ji

Potassium ionic sieve membrane was synthesized on porous α-Al2O3 tube support by the hydrothermal synthesis. The zeolite membranes were characterized by means of XRD and SEM. And the single-gas permeability through the membranes and selectivity to K+, Na+, Ca2+, Mg2+ were measured. The results show that the ideal separation factor is 3.68, which is close to Knudsen diffusion ratio 3.74 for H2/N2; the separation factors of the potassium ionic sieve membrane are , , respectively, indicating its high separation selectivity to potassium ion.


2019 ◽  
Vol 72 (5) ◽  
pp. 392 ◽  
Author(s):  
Yohsuke Nikawa ◽  
Seiji Tsuzuki ◽  
Hiroyuki Ohno ◽  
Kyoko Fujita

We investigated the hydration states of cholinium phosphate-type ionic liquids (ILs) in relation to ion structure, focusing on the influence of the hydroxyl group of the cation and the alkyl chain length of the anion. Water activity measurements provided information on the macroscopic hydration states of the hydrated ILs, while NMR measurements and molecular dynamics simulations clearly showed the microscopic interactions and coordination of the water molecules. The hydrogen bonding networks in these ILs were influenced by the anion structure and water content, and the mobility of water molecules was influenced by the number of hydroxyl groups in the cation and anion.


Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2479 ◽  
Author(s):  
Artyom V. Belesov ◽  
Anton V. Ladesov ◽  
Ilya I. Pikovskoi ◽  
Anna V. Faleva ◽  
Dmitry S. Kosyakov

Ionic liquids (ILs) based on 1-butyl-3-methylimidazolium (bmim) cation have proved to be promising solvents for the fractionation of plant biomass with the production of cellulose and lignin. This study deals with the characterization of lignins isolated from coniferous (spruce) wood using [bmim]OAc and [bmim]MeSO4 ionic liquids and their binary mixtures with DMSO (80:20). Molecular weight distributions, functional composition, and structural features of IL lignins were studied by size-exclusion chromatography, NMR spectroscopy (1D and 2D) and atmospheric pressure photoionization high-resolution mass spectrometry. It was shown that the interaction of ILs with lignin leads to significant chemical changes in the biopolymer; a decrease in the degree of polymerization and in the content of free phenolic hydroxyl groups due to alkylation, the disappearance (in the case of [bmim]OAc) of carbonyl groups and a significant destruction of β-O-4 bonds. The chemical reactions between lignin and 1-butyl-3-methylidazolium cation with covalent binding of ionic liquids or products of their decomposition is evidenced by the presence of a large number of nitrogen-containing oligomers in IL lignins.


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