• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3532-3540
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• 2011

In order to improve flux of PTMSP/PDMS dense membrane, PTMSP/PDMS-PEI composite membrane with PEI support was prepared by phase inversion process and dip coating. These membranes were evaluated in terms of the removal of volatile organic compounds such as PCE, TCE, chloroform, 1,1,1-trichloroethane from wastewater by pervaporation. The selectivity and flux of PTMSP/PDMS dense membranes was in the range of 216.2 to 2394.4 and 244.3 to 428.2g/m2h, respectively. And pervaporation property of PTMSP/PDMS-PEI composite membrane was in the range of 215.5 to 2404.2 and 390.4 to 728.6g/m2h, respectively. PTMSP/PDMS-PEI composite membrane has remarkably greater flux than dense membranes with similar selectivity. It was possible for polymeric membranes used in this study to remove PCE selectively which is dissolved small quantity in water among other separable solutes. PTMSP/PDMS-PEI composite membrane showed the best performances among the silicone polymeric membranes, and has better durability and mechanical strength than dense membranes. PTMSP/PDMS-PEI composite membrane should be a useful candidate for the removal of volatile organic compounds dissolved in wastewater.

• Membrane Journal
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• v.22 no.5
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• pp.309-317
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• 2012

In this study, PTMSP/LDH composite membranes were prepared by the solution intercalation method with 1, 3, and 5 wt% LDH contents to PTMSP. To investigate the physico-chemical characteristics of composite membranes, the analytical methods such as FT-IR, TGA, XRD, UTM, and SEM have been utilized, and the gas permeability and selectivity properties of $H_2$, $N_2$, and $CO_2$ were evaluated. The permeability of the PTMSP/LDH composite membranes decreased as LDH content increased and the selectivity $H_2$ and $CO_2$ showed the maximum value at 5 wt% of LDH content. Permeability of PTMSP/LDH composite membrane increased as the gas permeation pressure increased. The difference of the increase in gas permeation pressure of the permeability of PTMSP/LDH composite membrane was slightly smaller than of PTMSP membrane.

• Membrane Journal
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• v.8 no.1
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• pp.42-49
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• 1998

Effects of operating time, pH, temperature, concentration and addition of proteolytic enzyme on permeate flux for the ultrafiltration of gelatin and bovine serum albumin(BSA) solutions were studied. The results showed that permeate flux of gelatin solution was maintained almost constant during the operating time, and that of BSA solution was decreased to 66% of the initial value after 40 min operation. The permeate flux of gelatin solution was increased by increasing temperature. The permeate flux of BSA solution was constant in the temperature range of 30~$50{\circ}C$, but increased at $60{\circ}C.$. The permeate fluxes of gelatin and BSA solution showed minimum values near the isoelectric point of pH 5.0. The permeate fluxes of 1%(w/v) and 6% gelatin solution were $43.0l/m^2\cdot hr$ and $13.5l/m^2\cdot hr$, respectively. Those of 1% and 4% BSA solution were $33.0l/m^2\cdot hr$ and $14.0l/m^2\cdot hr$, respectively. The permeate fluxes of gelatin and BSA solutions were decreased to 68.6% and 57.6% of their initial values by increasing their concentration, respectively. The permeate fluxes of gelatin and BSA solutions were enhanced by 30% with the addition of proteolytic enzyme.

• Membrane Journal
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• v.19 no.4
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• pp.261-267
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• 2009

Polyimide which is the glassy polymer has high chemical resistance, thermal stability and high mechanical property. In this study, the polyimide hollow fiber membranes were prepared by the dry-jet wet phase inversion in order to investigate the permeation porperties of the $H_2S$ and $CH_4$. The morphology of prepared hollow fiber membranes and their permeation behaviors of $H_2S$ and $CH_4$ before and after silicon coating were evaluated. The permeance of $H_2S$ and $H_2S/CH_4$ selectivity increased due to plasticization with increasing the feed pressure. The permeance of KSM03b and selectivity of KSM03d were highest among the three type membranes used this experiments. The permeance decreased but the $H_2S/CH_4$ selectivity increased with increasing the air gap. The permeance reduced after silicon coating. However, the selectivity increased and the selectivity of KSM03d was 275 at 7 atm.

• Membrane Journal
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• v.11 no.1
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• pp.50-59
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• 2001

Influence of concentration polarization has been investigated on the vapor permeation of VOCs/$N_2$ mixture. Po]y(dimethylsiloxane)(PD,vIS) membrane which had a good affinit~, toward VOCs was emploj,'c'Cl in this study. The chlorinated hydmcarbons which were part of homologous series of chrolomelhane and chrolocthane were used as organic vapor. The vapor permeation experiments were calTied out at various VOCs feed concentrations. operating temperatures and feed flow rates. With decreasing feed flow rate. the membrane perfonnance, that is. penneation rate and selectivity were reduced in the permeation of VOCs/$N_2$ mixture. Especially the reducing of the membrane performance was founel to be more significant when the condensibility of voe was greater. voe content in the feed mixture was higher or operating temperature was lower. These observations were discussed in terms of the influence of con-centration polarizalion on the permeation of VOCSINl mixture through the PDMS membrane.

• Membrane Journal
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• v.18 no.2
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• pp.146-156
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• 2008

In this study, PTMSP of high permeability and high molecular weight was synthesized, and PTMSP-PDMS graft copolymer was synthesized from poly [1-(trimethylsily)propyne] (PTMSP) and hydroxy-terminated poly(dimethylsiloxane) (PDMS). The PTMSP-PDMS-silica composites were prepared by the addition of 15, 30, or 50 wt% tetraethoxysilane (TEOS) to PTMSP-PDMS graft copolymer by sol-gel process. To investigate the physico-chemical characteristics of PTMSP-PDMS-silica/PEI composite membranes, the analytical methods such as $^1H$-NMR, FT-IR, TGA, XPS, GPC, and SEM have been utilized. The gas permeability and selectivity properties of $H_2,\;O_2,\;N_2,\;CO_2,\;CH_4,\;n-C_4H_{10}$, were evaluated. Permeability of the composite membranes increased as TEOS content and pressure increased. Selectivity of $H_2,\;O_2,\;N_2,\;CO_2,\;CH_4,\;and\;n-C_4H_{10}$, showed the maximum value at 30 wt% of TEOS content and decreased thereafter.

• Membrane Journal
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• v.22 no.2
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• pp.142-154
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• 2012

In order to remove $CO_2$ from the DME plant process, we investigated the composite membrane with rubbery polymers as the separation layer and its separation performance of $CO_2$ and $H_2$. Hollow fiber membranes for supporting layer were prepared by solution spinning method. In case of using PDMS as a separation layer, the composite membranes showed the permeation rates of $CO_2$ were over 300 GPU and minimum $CO_2/H_2$ selectivitties were 4.3 and in case of using PEBAX as a separation layer, the composite membranes showed the permeation rates of $CO_2$ were over 120 GPU and minimum $CO_2/H_2$ selectivities were 5.

• Membrane Journal
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• v.22 no.5
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• pp.369-380
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• 2012

A one-dimensional numerical model based on the energy and mass equations have been developed to predict the trans membrane water vapor flux and thermal efficiency under various operating conditions in Direct Contact Membrane Distillation (DCMD) process. The model validation have been carried out by experimental data from literature and showed good agreement. The effect of operating parameters such as brine inlet temperature and velocity, and distillate inlet temperature and velocity to increase water vapor flux and thermal efficiency were predicted by the steady-state model. The results showed that the inlet temperature and velocity in brine side are dominant factors to control the water vapor flux and thermal efficiency because the effect of inlet temperature and velocity in brine side showed the higher water vapor flux and thermal efficiency than that of inlet temperature and velocity in distillate side. The water vapor flux was increased 3.4 times in the range of 21.22 $kg/m^2h$ to 71.26 $kg/m^2h$ and the thermal efficiency was increased 37.5% in that of 0.556 to 0.765 with increasing brine inlet temperature from $60^{\circ}C$ to $95^{\circ}C$. Meanwhile, the water vapor flux was increased 30% in that of 27.91 $kg/m^2h$ to 36.33 $kg/m^2h$ and thermal efficiency increased 7.5% in that of 0.6 to 0.646 as the brine inlet velocity was increased from 60 m/h to 300 m/h.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.416-422
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• 1993

In order to prepare high performance polymeric membrane, the crosslinked chitosan(C. Chitosan)membrane was prepared, the transport and the selective separation of the metal ions through the membrane were investigated. It was observed that the transport rates of the metal ions through the membrane increased according to the decreasing of the initial pH in downstream solution. Proton pump mechanism for this transport phenomenon was suggested. The transport selectivity is dependent on the selective adsorption resulting from the complex formation of chitosan with each metal ion. The separatin factor(${\alpha}_{Cu}{^{2+}}$) for the membrane was 9.5.

• Membrane Journal
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• v.6 no.4
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• pp.284-288
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• 1996

The crosslinked PVA/PAA membranes developed in our laboratory have been characterized for water-isopropyl alcohol mixture in terms of permeabilities and separation factor. When the feed mixture was 12wt% water, the permeability and the separation factor for PVA/PAA=75/25 membrane show $63g/m^{2}h$ and 1520 at $80^{\circ}C$, respectively. In case of 5wt% water in feed mixture, the permeability for PVA/PAA=75/25 membrane is $56g/m^{2}h$ at 8$0^{\circ}C$ while the separation factor is 1563.