• Membrane Journal
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• v.32 no.1
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• pp.74-82
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• 2022

The objective of this work was to investigate the gas permeation properties of CO₂ and CH₄ for PEBAX^®/TS-530 hybrid membranes and compare with pure PEBAX^®-1657 membrane. With FTIR and XRD it was possible to confirm that TS-530 was dispersed well in PEBAX^® matrix. Compared with pure PEBAX^® membrane, ideal separation factor for PEBAX^®/TS-530 (10 wt%) hybrid membrane was enhanced a little. As the amount of TS-530 was increased, the gas permeability coefficients of both CO₂ and CH₄ were increased, while the ideal separation factor was decreased. This results were explained by the reduction of crystallinity of polyamide block and interchain distance caused by introduction of inorganic nanoparticles. And fumed silica might tend to agglomerate, resulting in forming nonselective nanogaps in the hybrid materials, thus the diffusivity would be enhanced at the expense of diffusivity selectivity.

• Membrane and Water Treatment
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• v.13 no.3
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• pp.121-128
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• 2022

A tremendous amount of energy resources is being wasted in cleaning wastewater to save the environment across the globe. Several different procedures are commercially available to process wastewater. In this work, membrane filtration technique is used to treat the textile wastewater because of its cost effectiveness and low environmental impacts. Mixed Matrix Membrane (MMM) consist of Polyvinyl Alcohol (PVA) in which Graphene Oxide (GO) was added as a filler material. Five different membranes by varying the quantity of GO were prepared. The prepared membrane has been characterized by Scanning Electron Microscopy (SEM), X-Ray Diffractometry (XRD), Fourier Transformed Infrared Spectroscopy (FTIR) and Water Contact Angle (WCA). The prepared membranes have been utilized to treat textile wastewater. The synthesized membranes are used for the elimination of total dissolve solids (TDS), total suspended solids (TSS), Methylene blue (MB) dye and copper metallic ions from textile wastewater. It is concluded that amount of GO has direct correlation with the quality of wastewater treatment. The maximum removal of TDS, TSS, MB and copper ions are found to be 7.42, 23.73, 50.53 and 64.5% respectively and are achieved by 0.02 wt% PVA-GO membrane.

• Membrane and Water Treatment
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• v.5 no.4
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• pp.265-279
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• 2014

Pervaporation is the most promising technique for the recovery of ethanol from the fermentation system. To date, extensive research has been conducted on the exploration of membrane materials with favorable properties. In this paper, we primarily review the performance of adsorbent-filled rubbery membranes. In addition, the fundamental mechanisms of ethanol and water molecules transportation through composite membranes are demonstrated, particularly from the perspective of cluster formation. Finally, future prospects are also analyzed to develop the guidelines for the future development of excellent membrane materials for ethanol concentration. This paper is not meant to be an exhaustive overview, rather a specialized summary that allows readers to select the information appropriated to their topics.

• Membrane Journal
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• v.28 no.1
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• pp.55-61
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• 2018

With vigorous development of petroleum and chemical industry, emission of carbon dioxide has attracted tremendous attention globally due to global warming problem and abnormal climate change. To address these problems, in this study, a PEGBEM-g-POEM graft copolymer with high $CO_2$ affinity was synthesized and $CaCO_3$ was incorporated to form mixed matrix membranes (MMMs) for enhancement of $CO_2$ permeance. By varying the addition weight of $CaCO_3$ in MMMs, high separation performance of $CO_2$ over $N_2$ was obtained. At 50 wt% loading of $CaCO_3$, the greatest separation performance was obtained with an enhanced $CO_2$ permeance from 22.5 to 28.16 GPU and slightly increased $CO_2/N_2$ selectivity from 44.7 to 45.42. It resulted from the increased $CO_2$ solubility of MMMs due to specific interaction between $CaCO_3$ and $CO_2$ molecules. Upon excess loading of $CaCO_3$, MMMs exhibited loss of $CO_2$ separation performance due to the formation of interfacial defects. Based on this result, it is considered that the proper addition of $CaCO_3$ is crucial for improvement of $CO_2$ separation performance.

• Membrane and Water Treatment
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• v.7 no.6
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• pp.507-520
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• 2016

The effect of ZnO on cellulose acetate in the removal of benzophenone-3 (BP-3) was investigated. The benzophenone-3 (BP-3) which is an endocrine disrupting chemical (EDC) was completely removed (100%) from the drinking water using Cellulose Acetate (CA) and zinc oxide (ZnO) composite membranes. The membranes were prepared by DIPS method and the filtration experiments were conducted by dead end filtration unit. The macrostructure of the membrane were studied by ATR-IR and XRD Spectra's. Atomic force microscopy (AFM) and Scanning electron microscopy (SEM) were used to study the micro properties of the membranes. The laboratory experiments such as water uptake study and pure water flux performed to confirm the increasing hydrophilicity. The enhancing hydrophilicity was confirmed with respect to higher the concentration of nanoparticles. Evaluation of BP-3 removal was carried in different experimental conditions, such as, different Trans membrane pressure and different concentration of feed. The membrane with low pressure showed better performance by rejecting 100% of BP-3. However, 1 ppm, 3 ppm and 6 ppm of feed solution was used and among them 3 ppm of feed solution gives 100% rejection. The ZnO nanoparticales enhances the performance of CA membrane by showing maximum rejection.

• Membrane and Water Treatment
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• v.8 no.5
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• pp.483-498
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• 2017

Novel mixed matrix membranes of Sodium Alginate (NaAlg) were developed by the incorporation ofunmodified, modified Phosphomolybdic acid (PMA) then cross-linked with glutaraldehyde externally. These membranes were prepared by the solution casting technique. Pervaporation (PV) experiments have been performed with pure NaAlg, unmodified NaAlg-PMA5, NaAlg-PMA10, modified NaAlg-mPMA5, and NaAlg-mPMA10 (wt. % of PMA 5 and 10) at 30, 40 and $50^{\circ}C$, to separate water-isopropanol feed mixtures containing 10-30 wt. % of water. Pervaporation results of NaAlg-mPMA10 produced a highest separation factor of 9028 with a flux of $0.269kg/m^2.h$ for 10 wt. % of water containing feed mixture. Both separation factor and flux for water increased significantly with increasing content of mPMA into NaAlg; a significant improvement in PV performance was observed for NaAlg-mPMA5 and NaAlg-mPMA10 membranes when compared to pure NaAlg& PMA-5, PMA-10 membrane.

• Membrane Journal
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• v.25 no.6
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• pp.496-502
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• 2015

Facilitated transport is one of the possible solutions to simultaneously improve permeability and selectivity, which is challenging in conventional polymer-based membranes. Olefin/paraffin separation using facilitated transport membrane has received much attention as an alternative solution to the conventional distillation process. Herein, we report olefin separation composite membranes based on the polymer blends containing $AgBF_4/Al(NO_3)_3$ mixed salts. Free radical polymerization process was used to synthesize an amphiphilic graft copolymer of poly(dimethyl siloxane)-graft- poly(ethylene glycol) methyl ether methacrylate (PDMS-g-POEM). In addition, poly(ethylene oxide) (PEO) was introduced to the PDMS-g-POEM graft copolymer to form polymer blends with various ratios. The propylene/propane mixed-gas selectivity and permeance reached up to 5.6 and 10.05 GPU, respectively, when the PEO loading was 70 wt% in polymer blend. The improvement of olefin separation performance was attributed to the olefin facilitating silver ions as well as the highly permeable blend matrix. The stabilization of silver ions in the composite membrane was achieved through the introduction of $Al(NO_3)_3$ which suppressed the reduction of silver ions to silver particles.

• Structural Engineering and Mechanics
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• v.13 no.4
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• pp.437-453
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• 2002

In this paper, dynamic stiffness and flexibility for circular membranes are analytically derived using an efficient mixed-part dual boundary element method (BEM). We employ three approaches, the complex-valued BEM, the real-part and imaginary-part BEM, to determine the dynamic stiffness and flexibility. In the analytical formulation, the continuous system for a circular membrane is transformed into a discrete system with a circulant matrix. Based on the properties of the circulant, the analytical solutions for the dynamic stiffness and flexibility are derived. In deriving the stiffness and flexibility, the spurious resonance is cancelled out. Numerical aspects are discussed and emphasized. The problem of numerical instability due to division by zero is avoided by choosing additional constraints from the information of real and imaginary parts in the dual formulation. For the overdetermined system, the least squares method is considered to determine the dynamic stiffness and flexibility. A general purpose program has been developed to test several examples including circular and square cases.

• Membrane Journal
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• v.24 no.6
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• pp.417-422
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• 2014

The poly(ethylene oxide) (PEO)/Ag Nanoparticles (NPs)/7,7,8,8-Tetracyanoquinodimethane (TCNQ) membrane was fabricated to obtain highly permeable facilitated olefin transport nanocomposite membrane, compared with PEO/Ag NPs/p-Benzoquinone (p-BQ) membrane. Polymer matrix, PEO and silver nanoparticle precursor $AgBF_4$ were fixed at 1 : 0.4 mole ratio and electron acceptor TCNQ content was controlled variously. And the best olefin separation performance was obtained at 1/0.4/0.004 mole ratio, and long-term separation performance was measured at this ratio. As a result, mixed-gas permeance decreased from 23 to 6 GPU, and selectivity decreased from 6 to 2 (propylene/propane) after 32 hours.

• Membrane Journal
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• v.33 no.5
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• pp.240-247
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• 2023

Even among gas separation methods, CO₂ capture and separation via membranes is an ever-growing field, with many different membrane compositions continually being developed. Ionic liquid (IL) based composite membranes show excellent performance values in separating CO₂. Similarly, various copolymer/IL composite membranes also display improved performance. The addition of fillers such as graphene oxide to these copolymer/IL composite membranes shows a further enhanced version of these fillers, most likely due to the strong interactions that occur between ILs and organic fillers, which consequently improves factors such as the affinity, selectivity, and adsorption of CO₂. Copolymer/IL composite membranes utilizing a metal-organic framework (MOF) showed improved CO₂ permeability. This review discusses the study of various combinations of ionic liquid and copolymer composite membranes for carbon dioxide separation.