Polymers

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16 pages, 4787 KiB

Open AccessArticle

Development of Polysulfone Membrane via Vapor-Induced Phase Separation for Oil/Water Emulsion Filtration

by Nafiu Umar Barambu, Muhammad Roil Bilad, Mohamad Azmi Bustam, Nurul Huda, Juhana Jaafar, Thanitporn Narkkun and Kajornsak Faungnawakij

Polymers 2020, 12(11), 2519; https://doi.org/10.3390/polym12112519 - 29 Oct 2020

Cited by 20 | Viewed by 3037

Abstract

The discharge of improperly treated oil/water emulsion by industries imposes detrimental effects on human health and the environment. The membrane process is a promising technology for oil/water emulsion treatment. However, it faces the challenge of being maintaining due to membrane fouling. It occurs [...] Read more.

The discharge of improperly treated oil/water emulsion by industries imposes detrimental effects on human health and the environment. The membrane process is a promising technology for oil/water emulsion treatment. However, it faces the challenge of being maintaining due to membrane fouling. It occurs as a result of the strong interaction between the hydrophobic oil droplets and the hydrophobic membrane surface. This issue has attracted research interest in developing the membrane material that possesses high hydraulic and fouling resistance performances. This research explores the vapor-induced phase separation (VIPS) method for the fabrication of a hydrophilic polysulfone (PSF) membrane with the presence of polyethylene glycol (PEG) as the additive for the treatment of oil/water emulsion. Results show that the slow nonsolvent intake in VIPS greatly influences the resulting membrane structure that allows the higher retention of the additive within the membrane matrix. By extending the exposure time of the cast film under humid air, both surface chemistry and morphology of the resulting membrane can be enhanced. By extending the exposure time from 0 to 60 s, the water contact angle decreases from 70.28 ± 0.61° to 57.72 ± 0.61°, and the clean water permeability increases from 328.70 ± 8.27 to 501.89 ± 8.92 (L·m⁻²·h⁻¹·bar⁻¹). Moreover, the oil rejection also improves from 85.06 ± 1.6 to 98.48 ± 1.2%. The membrane structure was transformed from a porous top layer with a finger-like macrovoid sub-structure to a relatively thick top layer with a sponge-like macrovoid-free sub-structure. Overall results demonstrate the potential of the VIPS process to enhance both surface chemistry and morphology of the PSF membrane. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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11 pages, 3126 KiB

Open AccessArticle

Functionalized KIT-6/Polysulfone Mixed Matrix Membranes for Enhanced CO₂/CH₄ Gas Separation

by Thiam Leng Chew, Sie Hao Ding, Pei Ching Oh, Abdul Latif Ahmad and Chii-Dong Ho

Polymers 2020, 12(10), 2312; https://doi.org/10.3390/polym12102312 - 09 Oct 2020

Cited by 8 | Viewed by 1975

Abstract

The development of mixed matrix membranes (MMMs) for effective gas separation has been gaining popularity in recent years. The current study aimed at the fabrication of MMMs incorporated with various loadings (0–4 wt%) of functionalized KIT-6 (NH₂KIT-6) [KIT: Korea Advanced Institute [...] Read more.

The development of mixed matrix membranes (MMMs) for effective gas separation has been gaining popularity in recent years. The current study aimed at the fabrication of MMMs incorporated with various loadings (0–4 wt%) of functionalized KIT-6 (NH₂KIT-6) [KIT: Korea Advanced Institute of Science and Technology] for enhanced gas permeation and separation performance. NH₂KIT-6 was characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and N₂ adsorption–desorption analysis. The fabricated membranes were subjected to FESEM and FTIR analyses. The effect of NH₂KIT-6 loading on the CO₂ permeability and ideal CO₂/CH₄ selectivity of the fabricated membranes were investigated in gas permeation and separation studies. The successfulness of (3-Aminopropyl) triethoxysilane (APTES) functionalization on KIT-6 was confirmed by FTIR analysis. As observed from FESEM images, MMMs with no voids in the matrix were successfully fabricated at a low NH₂KIT-6 loading of 0 to 2 wt%. The CO₂ permeability and ideal CO₂/CH₄ selectivity increased when NH₂KIT-6 loading was increased from 0 to 2 wt%. However, a further increase in NH₂KIT-6 loading beyond 2 wt% led to a drop in ideal CO₂/CH₄ selectivity. In the current study, a significant increase of about 47% in ideal CO₂/CH₄ selectivity was achieved by incorporating optimum 2 wt% NH₂KIT-6 into the MMMs. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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15 pages, 2070 KiB

Open AccessArticle

The Effect of Conformation Order on Gas Separation Properties of Polyetherimide Ultem Films

by Julia Kostina, Sergey Legkov, Alexander Kolbeshin, Roman Nikiforov, Denis Bezgin, Alexander Yu. Nikolaev and Alexander Yu. Alentiev

Polymers 2020, 12(7), 1578; https://doi.org/10.3390/polym12071578 - 16 Jul 2020

Cited by 4 | Viewed by 2366

Abstract

Changes of the spectral characteristics of absorption bands depending on the films’ treatment method were registered for polyetherimide Ultem films. The possibility of selection of structural criteria (the ratio of the functional groups absorption bands intensities) showing all conformational changes in elementary unit [...] Read more.

Changes of the spectral characteristics of absorption bands depending on the films’ treatment method were registered for polyetherimide Ultem films. The possibility of selection of structural criteria (the ratio of the functional groups absorption bands intensities) showing all conformational changes in elementary unit with metrological processing of the results is shown. It is demonstrated that film formation from chloroform solution leads to elementary unit fragments, Ph–O–Ph′, which have an effect on macromolecule conformation and result in increasing of space between fragments of macromolecules (local polymer matrix packing loosening). Desorption of residual chloroform from films by ethanol or supercritical CO₂ leads to a change of conformers set in Im–Ph–Im′ units. Quantum chemical modeling showed the possibility of convergence of these fragments in neighboring macromolecules, and consequently of interchain π–π interaction (local densification of chain packing of the polymer matrix). After annealing at a temperature higher than glass transition temperature, the polyetherimide film exhibits the most disordered (amorphous) state at all of the fragments. It is demonstrated that the results, obtained by the combination of theoretical and experimental vibrational spectroscopy methods, are in good agreement with data of chain packing ordering found by analysis of gas separation parameters. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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9 pages, 3395 KiB

Open AccessArticle

CO₂ Separation with Polymer/Aniline Composite Membranes

by Hwa Jin Lee and Sang Wook Kang

Polymers 2020, 12(6), 1363; https://doi.org/10.3390/polym12061363 - 17 Jun 2020

Cited by 9 | Viewed by 2710

Abstract

Polymer composite membranes containing aniline were prepared for CO₂/N₂ separation. Aniline was selected for high separation performance as an additive containing both the benzene ring to interfere with gas transport and an amino group that could induce the accelerated transport [...] Read more.

Polymer composite membranes containing aniline were prepared for CO₂/N₂ separation. Aniline was selected for high separation performance as an additive containing both the benzene ring to interfere with gas transport and an amino group that could induce the accelerated transport of CO₂ molecules. As a result, when aniline having both a benzene ring and an amino group was incorporated into polymer membranes, the selectivity was largely enhanced by the role of both gas barriers and CO₂ carriers. Selective layers coated on the polysulfone were identified by scanning electron microscopy (SEM) images and the interaction with aniline in the polymer matrix was confirmed by FT-IR spectroscopy. The binding energy of oxygen in the polymer matrix was investigated by XPS, and the thermal stability of the composite membrane was confirmed by TGA. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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18 pages, 4000 KiB

Open AccessArticle

High Selective Composite Polyalkylmethylsiloxane Membranes for Pervaporative Removal of MTBE from Water: Effect of Polymer Side-chain

by Ilya Borisov, Ivan Podtynnikov, Evgenia Grushevenko, Olga Scharova, Tatiana Anokhina, Sergey Makaev, Alexey Volkov and Vladimir Volkov

Polymers 2020, 12(6), 1213; https://doi.org/10.3390/polym12061213 - 26 May 2020

Cited by 9 | Viewed by 3032

Abstract

For the first time, the effect of the side-chain in polyalkylmethylsiloxane towards pervaporative removal of methyl tert-butyl ether (MTBE) from water was studied. The noticeable enhancement of separation factor during the pervaporation of 1 wt.% MTBE solution in water through the dense film [...] Read more.

For the first time, the effect of the side-chain in polyalkylmethylsiloxane towards pervaporative removal of methyl tert-butyl ether (MTBE) from water was studied. The noticeable enhancement of separation factor during the pervaporation of 1 wt.% MTBE solution in water through the dense film (40–50 µm) can be achieved by substitution of a methyl group (separation factor 111) for heptyl (161), octyl (169) or decyl (180) one in polyalkylmethylsiloxane. Composite membrane with the selective layer (~8 µm) made of polydecylmethylsiloxane (M10) on top of microfiltration support (MFFK membrane) demonstrated MTBE/water separation factor of 310, which was 72% greater than for the dense film (180). A high separation factor together with an overall flux of 0.82 kg·m⁻²·h⁻¹ allowed this M10/MFFK composite membrane to outperform the commercial composite membranes. The analysis of the concentration polarization modulus and the boundary layer thickness revealed that the feed flow velocity should be gradually increased from 5 cm·s⁻¹ for an initial solution (1 wt.% of MTBE in water) to 13 cm·s⁻¹ for a depleted solution (0.2 wt.% of MTBE in water) to overcome the concentration polarization phenomena in case of composite membrane M10/MFFK (T_exp = 50 °C). Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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25 pages, 6859 KiB

Open AccessArticle

Novel Mixed Matrix Sodium Alginate–Fullerenol Membranes: Development, Characterization, and Study in Pervaporation Dehydration of Isopropanol

by Mariia Dmitrenko, Vladislav Liamin, Anna Kuzminova, Anton Mazur, Erkki Lahderanta, Sergey Ermakov and Anastasia Penkova

Polymers 2020, 12(4), 864; https://doi.org/10.3390/polym12040864 - 09 Apr 2020

Cited by 28 | Viewed by 2980

Abstract

Novel mixed matrix dense and supported membranes based on biopolymer sodium alginate (SA) modified by fullerenol were developed. Two kinds of SA–fullerenol membranes were investigated: untreated and cross-linked by immersing the dry membranes in 1.25 wt % calcium chloride (CaCl₂) in [...] Read more.

Novel mixed matrix dense and supported membranes based on biopolymer sodium alginate (SA) modified by fullerenol were developed. Two kinds of SA–fullerenol membranes were investigated: untreated and cross-linked by immersing the dry membranes in 1.25 wt % calcium chloride (CaCl₂) in water for 10 min. The structural and physicochemical characteristics features of the SA–fullerenol composite were investigated by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopic methods, scanning electron (SEM) and atomic force (AFM) microscopies, thermogravimetric analysis (TGA), and swelling experiments. Transport properties were evaluated in pervaporation dehydration of isopropanol in a wide concentration range. It was found that the developed supported cross-linked SA-5/PAN^CaCl2 membrane (modified by 5 wt % fullerenol) possessed the best transport properties (the highest permeation fluxes 0.64–2.9 kg/(m² h) and separation factors 26–73,326) for the pervaporation separation of the water–isopropanol mixture in the wide concentration range (12–90 wt % water) at 22 °C and is suitable for the promising application in industry. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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17 pages, 2725 KiB

Open AccessArticle

Novel Polyester Amide Membranes Containing Biquinoline Units and Complex with Cu(I): Synthesis, Characterization, and Approbation for n-Heptane Isolation from Organic Mixtures

by Alexandra Pulyalina, Ilya Faykov, Vera Nesterova, Mikhail Goikhman, Irina Podeshvo, Nairi Loretsyan, Alexander Novikov, Iosif Gofman, Alexander Toikka and Galina Polotskaya

Polymers 2020, 12(3), 645; https://doi.org/10.3390/polym12030645 - 12 Mar 2020

Cited by 10 | Viewed by 2724

Abstract

The wide possibilities of designing a chemical structure and creating complexes with transition metals make polymers of heteroaromatic structure interesting objects, from both scientific and practical aspects. In this work, modern biquinoline-containing polymers, namely polyester amide (PEA) and its metal–polymer complex (PEA–Cu(I)), were [...] Read more.

The wide possibilities of designing a chemical structure and creating complexes with transition metals make polymers of heteroaromatic structure interesting objects, from both scientific and practical aspects. In this work, modern biquinoline-containing polymers, namely polyester amide (PEA) and its metal–polymer complex (PEA–Cu(I)), were synthesized and used to form dense flat membranes. A comparative study of their morphology, same physical properties (density, free volume, and contact angles), and thermomechanical characteristics was carried out. The transport properties of the modern membranes were studied during pervaporation, to solve a problem of n-heptane isolation from its binary mixtures with thiophene and methanol. It was shown that only the PEA membrane is selective for the separation of thiophene impurities from the mixture with n-heptane. In pervaporation of methanol/n-heptane mixture, the РЕА–Cu(I) membrane exhibits significantly higher pervaporation separation index, as compared with that of the РЕА membrane. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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14 pages, 5166 KiB

Open AccessArticle

Improved Desulfurization Performance of Polyethyleneglycol Membrane by Incorporating Metal Organic Framework CuBTC

by Caibin Cai, Xiaotao Fan, Xiaolong Han, Jiding Li and Harsh Vardhan

Polymers 2020, 12(2), 414; https://doi.org/10.3390/polym12020414 - 11 Feb 2020

Cited by 19 | Viewed by 2923

Abstract

In this paper, copper benzene-1,3,5-tricarboxylate (CuBTC) was incorporated into polyethylenglyol (PEG) to prepare a mixed matrix membrane (MMM) for pervaporation desulfurization. The characterization results showed that the prepared CuBTC particles had an ideal octahedral shape and micropores. The Cu²⁺ in CuBTC interacts [...] Read more.

In this paper, copper benzene-1,3,5-tricarboxylate (CuBTC) was incorporated into polyethylenglyol (PEG) to prepare a mixed matrix membrane (MMM) for pervaporation desulfurization. The characterization results showed that the prepared CuBTC particles had an ideal octahedral shape and micropores. The Cu²⁺ in CuBTC interacts with thiophene via π-complexation, thus enhancing the separation performance of the hybrid membranes. The effect of CuBTC content and the operating condition on the pervaporation performance of the MMMs was investigated. An optimal pervaporation separation performance was acquired with a permeation flux of 2.21 kg/(m²·h) and an enrichment factor of 8.79, which were increased by 100% and 39% compared with the pristine PEG membrane. Moreover, the CuBTC-filled PEG membrane showed a good stability in the long-term desulfurization under a high operating temperature of 75 °C for five days. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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19 pages, 2658 KiB

Open AccessArticle

Transport Properties of Thermoplastic R-BAPB Polyimide: Molecular Dynamics Simulations and Experiment

by Igor V. Volgin, Maria V. Andreeva, Sergey V. Larin, Andrey L. Didenko, Gleb V. Vaganov, Ilya L. Borisov, Alexey V. Volkov, Leonid I. Klushin and Sergey V. Lyulin

Polymers 2019, 11(11), 1775; https://doi.org/10.3390/polym11111775 - 29 Oct 2019

Cited by 18 | Viewed by 4776

Abstract

The present work evaluates the transport properties of thermoplastic R-BAPB polyimide based on 1,3-bis(3,3′,4,4′-dicarboxyphenoxy)benzene (dianhydride R) and 4,4′-bis(4-aminophenoxy)biphenyl (diamine BAPB). Both experimental studies and molecular dynamics simulations were applied to estimate the diffusion coefficients and solubilities of various gases, such as helium (He), [...] Read more.

The present work evaluates the transport properties of thermoplastic R-BAPB polyimide based on 1,3-bis(3,3′,4,4′-dicarboxyphenoxy)benzene (dianhydride R) and 4,4′-bis(4-aminophenoxy)biphenyl (diamine BAPB). Both experimental studies and molecular dynamics simulations were applied to estimate the diffusion coefficients and solubilities of various gases, such as helium (He), oxygen (O₂), nitrogen (N₂), and methane (CH₄). The validity of the results obtained was confirmed by studying the correlation of the experimental solubilities and diffusion coefficients of He, O₂, and N₂ in R-BAPB, with their critical temperatures and the effective sizes of the gas molecules, respectively. The solubilities obtained in the molecular dynamics simulations are in good quantitative agreement with the experimental data. A good qualitative relationship between the simulation results and the experimental data is also observed when comparing the diffusion coefficients of the gases. Analysis of the Robeson plots shows that R-BAPB has high selectivity for He, N₂, and CO₂ separation from CH₄, which makes it a promising polymer for developing gas-separation membranes. From this point of view, the simulation models developed and validated in the present work may be put to effective use for further investigations into the transport properties of R-BAPB polyimide and nanocomposites based on it. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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17 pages, 2454 KiB

Open AccessArticle

Asymmetric Membranes Based on Copolyheteroarylenes with Imide, Biquinoline, and Oxazinone Units: Formation and Characterization

by Galina Polotskaya, Alexandra Pulyalina, Mikhail Goikhman, Irina Podeshvo, Iosif Gofman, Sergey Shugurov, Valeriia Rostovtseva, Ilya Faykov, Maksim Tataurov, Alexander Toikka and Alexander Polotsky

Polymers 2019, 11(10), 1542; https://doi.org/10.3390/polym11101542 - 22 Sep 2019

Cited by 8 | Viewed by 2674

Abstract

Modern ultrafiltration requires novel perfect membranes with narrow pore size, high porosity, and minimal pore tortuosity to achieve high separation performance. In this work, copolyamic acid (co-PAA) was synthesized and used for the preparation of asymmetric porous membranes by phase inversion technique. Several [...] Read more.

Modern ultrafiltration requires novel perfect membranes with narrow pore size, high porosity, and minimal pore tortuosity to achieve high separation performance. In this work, copolyamic acid (co-PAA) was synthesized and used for the preparation of asymmetric porous membranes by phase inversion technique. Several co-PAA membranes were heated up to 250 °C; during heating, they undergo solid-phase transformation into co-polybenzoxazinoneimide (co-PBOI) via dehydration and cyclization. Comparative characterization of both co-PAA and co-PBOI membranes was realized by scanning electron microscopy, mechanical testing, thermogravimetric analysis, and ultrafiltration experiments. Membrane calibration was carried out using a mixture of seven proteins with different molecular weights. During heat treatment, the molecular weight cut-off of the membranes decreased from 20 × 10³ g/mol (co-PAA) to 3 × 10³ g/mol (co-PBOI). Abnormally low dispersions of rejection (0.3 for co-PAA and 0.45 for co-PBOI) were observed for the studied membranes; this fact indicates that the membranes possess enhanced resolving power. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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Review

Jump to: Research

22 pages, 1794 KiB

Open AccessReview

Application of Polymer Membranes for a Purification of Fuel Oxygenated Additive. Methanol/Methyl Tert-butyl Ether (MTBE) Separation via Pervaporation: A Comprehensive Review

by Alexandra Pulyalina, Valeriia Rostovtseva, Ilya Faykov and Alexander Toikka

Polymers 2020, 12(10), 2218; https://doi.org/10.3390/polym12102218 - 27 Sep 2020

Cited by 15 | Viewed by 3047

Abstract

Methyl Tert-butyl Ether (MTBE) remains the most popular fuel additive to improve fuel performance and reduce the emission of hazardous components. The most common method of MTBE production is a catalytic synthesis with a great excess of methanol to improve the reaction yield. [...] Read more.

Methyl Tert-butyl Ether (MTBE) remains the most popular fuel additive to improve fuel performance and reduce the emission of hazardous components. The most common method of MTBE production is a catalytic synthesis with a great excess of methanol to improve the reaction yield. The problems of obtaining pure MTBE from the final product have determined the search for new techniques; primarily membrane methods. Pervaporation as an optimal membrane process for highly selective separation of organic mixtures is of particular interest. This review is focused on analysis of the research works on the various polymer membranes and their efficiency for the separation of the azeotropic methanol/MTBE mixture. Currently the most popular materials with optimal transport properties are poly(vinyl alcohol), cellulose acetate and polyheteroarylenes. Mixed matrix membranes (MMM) are highly effective as well as they show overall operational stability. Full article

(This article belongs to the Special Issue Polymeric Membrane Materials for Separation Liquid and Gas Mixtures)

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