• Membrane Journal
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• v.23 no.1
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• pp.45-53
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• 2013

Membrane filtration processes are increasingly popular for drinking water treatment that requires high quality of water. But pre-treatment system (Coagulation/Flocculation/Sedimentation) requires increased footprint and installation cost. In addition, 5~10% of the concentrate are formed. In this study, the pressurized PVDF membrane (ECONITY Co., Ltd.) system was tested with surface water (Han River, South Korea) without pre-treatment. As a result, permeate flux was operated between 1 m/d and 2.4 m/d (at $25^{\circ}C$) without chemical cleaning for one year and membrane permeate turbidity was maintained stably under 0.05 NTU regardless of raw water turbidity. And we studied application of concetrate treatment of pressurized PVDF membrane by submerged PE membrane (ECONITY Co., Ltd.). As a result, we increased recovery of total treatment process to 99.5%.

• Membrane Journal
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• v.30 no.6
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• pp.409-419
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• 2020

In this study, PEBAX/ZIF-8 and PEBAX/amineZIF-8 composite membranes were prepared according to the content of zeolitic imidazolate framework-8 (ZIF-8), amine-modified ZIF-8 (amineZIF-8), the gas permeability properties of N2 and CO2 were investigated for each composite membrane. In the case of the PEBAX/ZIF-8 composite membrane, the permeability of N2 and CO2 increased as the ZIF-8 content increased, and in the case of the PEBAX/amineZIF-8 composite membrane, the permeability of N2 and CO2 increased up to 20 wt% of amineZIF-8, but decreased at the higher content. CO2/N2 ideal selectivity increased up to 20 wt% of ZIF-8 and amineZIF-8 contents in both PEBAX/ZIF-8 and PEBAX/ amineZIF-8 composite membranes, and then decreased thereafter, in the case of PEBAX/amineZIF-8 composite membrane was less decreased. The reason for the highest CO2/N2 ideal selectivity at 20 wt% of amineZIF-8 is that amine modification improved the compatibility between PEBAX and amineZIF-8, and thus amineZIF-8 was evenly dispersed in PEBAX, resulting in the greatest effect of the porous ZIF-8 with a 3.4 Å pore size and the amine with affinity for CO2.

• Membrane Journal
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• v.31 no.6
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• pp.404-416
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• 2021

In this study, a mixed matrix membrane was prepared by varying the contents of GO and PEI-GO synthesized in PEBAX2533, and the permeation characteristics of N₂ and CO₂ were studied. The N₂ and CO₂ permeability of the PEBAX/GO mixed membrane decreased as the GO content increased, and showed the highest CO₂/N₂ selectivity of 58.9 at GO 0.3 wt%. For the PEBAX/PEI-GO mixed membrane, the N₂ permeability decreased as the PEI-GO content increased, and the CO₂ permeability showed a different trend according to the PEI-GO content. Overall, the CO₂/N₂ selectivity was higher than that of the PEBAX/GO mixed membrane. In particular, PEI-GO 0.3 wt% showed the highest CO₂/N₂ selectivity of 73.5 among the mixed membranes, and a positive result was obtained as it was located above the Robeson upper bound. This is believed to be due to the molecular sieving channel effect resulting from the original GO structure, the functional groups present in the structure of GO having affinity for CO₂, and the effect of amine bound to PEI by modifying GO into PEI.

• Journal of the Korean Ceramic Society
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• v.44 no.1 s.296
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• pp.58-64
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• 2007

In this study, we investigated $Li_2ZrO_3$ membrane as a candidate material for high-temperature $CO_2$ separation and evaluated mechanical property. $Li_2ZrO_3$ powder was synthesized by solid state reaction of $Li_2CO_3\;and\;ZrO_2$. Then we fabricated $Li_2ZrO_3$ tape using tape casting method. Dense $Li_2ZrO_3$ membrane prepared by sintering at $1600^{\circ}C$ for 2 h after pressing $Li_2ZrO_3$ tape using lamination machine. Mechanical properties before and after $CO_2$ absorption of fabricated $Li_2ZrO_3$ membrane such as Hertzian indentation, Victors hardness and 3-point bending testing were evaluated.

• Membrane Journal
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• v.28 no.4
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• pp.233-242
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• 2018

To study gas membrane using GO (graphene oxide), the PEBAX [poly(ether-block-amide)]-GO polymer composite membrane was prepared by adding GO to PEBAX. Through this composite membrane, gas permeation characteristics for $H_2$, $N_2$, $CH_4$, and $CO_2$ were studied. As a result of the gas permeation test, the permeability of $N_2$, $CH_4$, and $CO_2$ to PEBAX-GO composite membranes gradually decreased as the GO content increased. On the other hand, the gas permeability of $H_2$ increased with the increase of GO content, and it was 21.43 barrer at the GO content of 30 wt%, which was about 5 times higher than that of PEBAX membrane. This is because the GO was easier to operate with a fast and selective gas transport channel for $H_2$ than other gases. The increased selectivity ($H_2/N_2$) and selectivity ($H_2/CH_4$) were influenced by the diffusion selectivity by the permeate gas size. The increased selectivity ($CO_2/N_2$) and selectivity ($CO_2/CH_4$) were more influenced by the solubility selectivity due to the affinity of $CO_2$ and GO for -COOH.

• Korean Membrane Journal
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• v.1 no.1
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• pp.59-64
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• 1999

A theoretical and experimental study made in order to determine the performance of mem-brane contactors in water carbonation is presented. In particular on the basis of experimental results pre-viously obtained it has been derived an expression in which the effect of some parameters as temprera-ture water and {{{{{CO }_{2 } }}}}} flow rate {{{{{CO }_{2 } }}}}} pressure trans-membrane pressure on the performance of the process is taken into account. The study refers to hollow fiber membrane contactors used for the experimental tests. The main scope has been to verify if by membrane contactors it is possible to reach the same de-gree of water carbonation as by trditional methods (1-5 g/1) and to derive for the module used a cor-relation able to describe the performance of the process at several operating conditions. The high {{{{{CO }_{2 } } }}}} removal observed confirms the interesting potentialties of membrane contactors also in gas streams purification.

• Membrane Journal
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• v.31 no.4
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• pp.268-274
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• 2021

One of the chronic problems in the issue of global warming is the emission of greenhouse gases. Carbon dioxide (CO₂), which accounts for the highest proportion of various greenhouse gases, has been continuously researched by humans to separate it. From this point of view, a poly(vinyl alcohol) (PVA)-based copolymer with acrylic acid monomer was utilized in a gas separation membrane in this study. We employed a free radical polymerization to fabricate PVA-g-PAA (VAA) graft copolymer. It was utilized in the form of a composite membrane on a polysulfone substrate. The proper amount of acrylic acid reduced the crystallinity of PVA and increased CO₂ solubility in separation membranes. In this perspective, we suggest the novel approach in CO₂ separation membrane area by grafting and solution-diffusion.

• Membrane Journal
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• v.12 no.3
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• pp.121-142
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• 2002

The $CO_2$ emission is the largest contribute for the green house effect. Among the existing chemical separation processes, the membrane separation technology is(/will be) the most potential process for $CO_2$, separation from flue gas. Based on the solution-diffusion theory and physical properties of carbon dioxide/nitrogen and the permeation data in the literature, the relationships between physico-chemical structures of polymeric membrane materials and the perm-selectivities for $CO_2$/$N_2$ gases were described in detail. The progress of membrane module and process development was introduced briefly. Finally, the worldwide research activity including South Korea's for carbon dioxide separation by membrane technology were introduced through the survey of papers and technical reports published.

• Journal of the Korean Ceramic Society
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• v.34 no.7
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• pp.747-757
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• 1997

ZSM-5 zeolite composite membranes have been synthesized from a silica sol solution containing TPABr as an organic template by the dip-coating and the pressurized-coating hydrothermal treatment techniques. The CO2 separation efficiency of synthesized composite membranes was also investigated. The permeation mechanism of CO2 through ZSM-5 membranses was the surface diffusion, and that of N2, O2, and He gases was Knudsen diffusion or activated diffusion depending on the synthetic method of membranes and the measurement temperature. The CO2/N2 separation factor of the membrane prepared by the dip-coating hydrothermal treatment was 2.5 at about 12$0^{\circ}C$, while the ZSM-5 composite membrane synthesized by the pressurized-coating hydrothermal treatment technique showed the CO2/N2 separation factor of 9.0 at room temperature higher than that ever reported in the literature.

• Journal of Hydrogen and New Energy
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• v.26 no.1
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• pp.45-53
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• 2015

The objective of this study is to develop a gas pro-treatment system for DME synthesis, wherein this system separates $CO_2$ from Flaring gas as Membrane, in order to save raw material ($CH_4$) cost of DME. In this study, hollow fiber membrane is developed, which is able to separate high-pressure gas, supported by polysulfone and coated with amorphous fluorinated polymer. Throughout the evaluation of the membrane's separation characteristics, the membrane is applied to this system. The membrane is designed by 2 stages for over 90% removal rate of $CO_2$ and over 90% recovery rate of $CH_4$. The bench scale of pro-treatment system is developed as $25Nm^3/hr$.