• Clean Technology
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• v.13 no.1 s.36
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• pp.79-84
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• 2007

Separation of ethylene from ethane and propylene from propane have been conducted using facilitated olefin transport membrane with SPEEK-Ag (Ag substituted sulfonated poly(ether ether ketone)). SPEEK was prepared by the sulfonation of PEEK using cone. $H_2SO_4$ and the reaction time affected the degree of sulfonation (DS) of the resulting SPEEK. SPEEK-Ag composite membrane was formed by soaking SPEEK in the polyester support into the Ag salt solution. With increasing the concentration of SPEEK in MeOH, the thickness of SPEEK on the polyester increased. The selectivity and the flux of SPEEK-Ag membrane for the separation of ethylene/ethane and propylene/propane were changed by the thickness of SPEEK layer on the top of polyester support. The anion of silver salt also affects the membrane performance.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.15-18
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• 1999

A simple mathematical model for facilitated mass transport through a fixed site carrier membrane was derived by assuming an instantaneous, microscopic concentration (activity) fluctuation. The current model demonstrates that the facilitation factor depends on the extent of concentration fluctuation, the time scale ratios of diffusion to chemical reaction and the ratio of the carrier concentration to the solute solubility in matrix. The model was examined against the experimental data on oxygen transport in membranes containing metallo-porphyrin carriers, and the agreement was exceptional (within 10% error). The basic concept of this approach was applied to separate olefin from olefin/paraffin mixtures. A proprietaty carrier, developed here, resulted that the selectivity of propylene over propane was more than 120 and the propylene permeance exceed 40 gpu.

• Korean Membrane Journal
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• v.8 no.1
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• pp.36-42
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• 2006

We have prepared new water-swollen chitosan-$Ag^+$ complex membranes and studied their permeation and separation behavior for propylene and propane gases. The $Ag^+$ containing chitosan complex membranes were prepared from chitosan and $AgNO_3$ aqueous solution. The $AgNO_3$ and water content in the membrane were controlled by adjusting $AgNO_3$ concentration of casting solution. The permeation properties of propylene and propane were investigated as a function of $AgNO_3$ concentration, and various operation conditions. High permeability of above 17 barrer and high selectivity of above 170 could be obtained with the membranes prepared from 3 M $AgNO_3$ aqueous solution. Periodic regeneration test confirmed these membranes could be very useful for the separation of propylene/propane and other olefin/paraffin separation.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.137-138
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• 2003

The worldwide annual production of polyolefins amounted to 60 million tons in 2000. During the process, 1-2 wt% of the olefin monomers have been emitted and flared into the air, causing the huge energy consumption and severe carbon dioxide emission. Recently, membrane process has been proved to be the most competitive among other separation processes in terms of cost of equipments, energy consumption and safety in this application. The performance of membrane process highly depends on the membrane properties and thus, it is very important to develop good membrane materials and composite membranes. We prepared PMDS dense and composite membranes and studied basic permeation behaviors of a series of olefins(ethylene, propylene, 1 -butylene), nitrogen and hydrogen as model gases.

• Membrane Journal
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• v.17 no.1
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• pp.1-13
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• 2007

Pervaporation process using membrane is newly emerging energy saying and cost effect process instead of distillation process. Especially, in pertrochemical industry, pervaporation process is a strong candidate to substitute the conventional energy consuming processes because that petrochemical industry has much energy consuming separation processes, many azeotrope mixtures to separate and needs to compact space to install new process units. Aromatic/aliphatic separation including benzene/cyclohexane mixture, olefin/paraffin separation, xylene isomer separation, reactive monomer recovery and sulfur compound removal from gasoline have been inversitigated for the application of pervaporation membrane process by many researchers and are under commercializing.

• Membrane Journal
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• v.15 no.2
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• pp.157-164
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• 2005

In this study, composite hollow fiber membranes were developed for the recovery of olefin monomers in polyolefin industry off-gases. Polyetherimide (PEI) hollow fiber support membranes were fabricated from spinning solutions containing PEI, NMP and polyethylene glycol (PEG). The influence of dope solution and inner coagulant composition on the permeation properties and structure of hollow fiber supports was examined. PDMS was used as a selective layer and coated on PEI hollow fiber support. The thickness of active layer was controlled by changing coating solution concentration. The permeation properties of hollow fiber supports and composite membranes were characterized with a pure gas permeation test. The optimized composite hollow fiber membrane has $10\;{\mu}m$ selective layer and shows excellent separation performance; the ideal selectivity of olefins over nitrogen is in the following order: 1-butylene (6.4) > propylene (17) > ethylene (97), which selectivity data are similar to the intrinsic olefin/nitrogen selectivities of PDMS. This confirms that the new composite hollow fiber membranes suitable for olefin off-gas recovery has developed successfully.

• Membrane Journal
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• v.25 no.5
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• pp.398-405
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• 2015

Facilitated transport is considered to be a possible solution to simultaneously improve permeability and selectivity, which is challenging in normal polymeric membranes based on solution-diffusion transport only. We investigated the effect of adding mesoporous $TiO_2$ ($m-TiO_2$) upon the separation performance of facilitated olefin transport membranes comprising poly(vinyl pyrrolidone), Ag nanoparticles, and 7,7,8,8-tetracyanoquinodimethane as the polymer matrix, olefin carrier, and electron acceptor, respectively. In particular, $m-TiO_2$ was prepared by means of a facile, mass-producible method using poly(vinyl chloride)-g-poly(oxyethylene methacrylate) graft copolymer as the template. The crystal phase of $m-TiO_2$ consisted of an anatase/rutile mixture, of crystallite size approximately 16 nm as determined by X-ray diffraction. The introduction of $m-TiO_2$ increased the membrane diffusivity, thereby increasing the mixed-gas permeance from 1.6 to 16.0 GPU ($1GPU=10^{-6}cm^3$(STP)/($s{\times}cm^2{\times}cmHg$), and slightly decreased the propylene/propane selectivity from 45 to 37. However, both the mixed-gas permeance and selectivity of the membrane containing $m-TiO_2$ rapidly decreased over time, whereas the membrane without $m-TiO_2$ had more stable long-term performance. This difference might be attributed to specific chemical interactions between $TiO_2$ and Ag nanoparticles, causing Ag to lose activity as an olefin carrier.

• Membrane Journal
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• v.28 no.4
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• pp.265-270
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• 2018

In previous studies, a poly(ethylene oxide)(PEO)/Ag nanoparicles (AgNPs)(precursor $AgBF_4$)/p-benzoquinone (p-BQ) composite membrane was prepared for olefin/paraffin separation and the performance of this composite membrane was maintained at a selectivity of 10 and a permeability of 15 GPU. However, since the price of $AgBF_4$ precursor is high, this study used $AgNO_3$ as a precursor of Ag nanoparticles which is competitive in terms of price. As a result, it was observed that the separation performance was not obtained because the existing $NO_3{^-}$ could surround AgNPs. In this study, we fabricated PEO, poly(vinyl alcohol)(PVA), and polyether block amide-1657 (PEBAX-1657) polymer composite membrane using electron acceptor 7,7,8,8-tetracyanoquinodimethane (TCNQ) for separation performance even when $AgNO_3$ was used as a precursor of Ag nanoparticles. As a result, it was analyzed that the performance was not observed regardless of the influence of the polymer and the electron acceptor, indicating that the anion of the precursor plays a crucial role in the separation performance.

• Membrane Journal
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• v.26 no.1
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• pp.32-37
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• 2016

The poly(vinyl alcohol) $(PVA)/AgCF_3SO_3/Al(NO_3)_3$ electrolyte membrane was fabricated to prepare for highly permeable facilitated olefin transport membrane, compared with poly(vinylpyrrolidone) $(PVP)/AgCF_3SO_3/Al(NO_3)_3$ complex. In order to examine the characteristics of $PVA/AgCF_3SO_3/Al(NO_3)_3$ membrane, we used the analytical methods such as SEM, FT-IR, and FT-Raman. The best separation performance was observed at the mole ratio of 1 : 1 : 0.01 $PVA/AgCF_3SO_3/Al(NO_3)_3$ among various $Al(NO_3)_3$ concentration. As a result, the selectivity was 12 and mixed-gas permeability was 3.5 Barrer. Furthermore, the selectivity and permeability remained constant for up to 115 h.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.15-22
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• 2008

Polyolefin block copolymer has been taking a great deal of attention due to their great potential in polymer industry since a new metallocene catalytic method for producing polyolefin block copolymer was developed by Dow Chemicals. However, so far, there was no systematic study of olefin block copolymer. In this review, Linear polyolefin block copolymers, containing semicrystalline poly (ethylene) (E) blocks and a rubbery block as a thermoplastic elastomer, were investigated in the viewpoint of microphase separation mode, microstructure, deformation behavior, and molecular architecture.