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A F Ismail - One of the best experts on this subject based on the ideXlab platform.

  • polyvinylidene fluoride and polyetherimide hollow fiber membranes for co2 stripping in membrane contactor
    Chemical Engineering Research & Design, 2014
    Co-Authors: R. Naim, A F Ismail, Ng Be Cheer, Mohd Sohaimi Abdullah
    Abstract:

    Porous polyvinylidene fluoride (PVDF) and polyetherimide (PEI) hollow fiber membranes incorporating polyethylene glycol (PEG) were prepared via spinning process for CO2 membrane stripping. CO2 loaded diethanolamine solution was used as liquid absorbent while N2 was used as a strip gas. The characterization study of the fibers was carried out in terms of permeation test, contact angle measurement and liquid entry pressure (wetting pressure). Performance study via membrane contactor stripping was carried out at specific operating condition. The experimental results showed that PVDF membrane have high gas permeation, effective surface porosity and contact angle despite having lower liquid entry pressure in comparison with PEI membrane. PVDF-PEG membrane showed the highest stripping flux of 4.0 × 10−2 mol m−2 s−1 at 0.7 ms−1 compared to that of PEI membrane. Although the stripping flux for PEI-PEG membranes was slightly lower than PVDF membrane (e.g. 3.5 × 10−2 mol m−2 s−1 at liquid velocity of 0.85 ms−1), the membrane wetting pressure of PEI membrane is higher than hydrophobic PVDF membrane. Long term performance of both membranes showed severe flux reduction but started to level-off after 30 h of operation.

  • Study on CO2 stripping from water through novel surface modified PVDF hollow fiber membrane contactor
    Chemical Engineering Journal, 2014
    Co-Authors: Masoud Rahbari-sisakht, Dipak Rana, Takeshi Matsuura, Daryoush Emadzadeh, Mahesh Padaki, A F Ismail
    Abstract:

    Abstract Dry–wet phased inversion method was used to fabricate polyvinylidene fluoride (PVDF) hollow fiber membranes. Different concentration of surface modifying macromolecules (SMM) i.e., 2, 4 and 6 wt.% were used as additives in the spinning dope. In the phase inversion SMM migrates to the membrane surface and changes the surface morphology with chemical properties on the membrane surface. This modification results into larger pore size, higher gas permeance, effective surface porosity and water contact angle. The surface modified membrane was used in membrane contactor for CO 2 stripping from water by using self-fabricated gas–liquid membrane contactor module. The result of CO 2 stripping experiment shows that the performance of surface modified membrane is better than plain PVDF membrane. CO 2 desorption flux increased with respect to SMM concentration, considerably. The membrane fabricated with 6 wt.% SMM as additive showed higher CO 2 desorption flux and efficiency of 2.1 × 10 −3 (mol m −2  s −1 ) and 80%, respectively at 200 ml/min of liquid flow rate. For this membrane CO 2 stripping flux was investigated for different liquid phase temperature. It was found that desorption flux increased by increasing liquid temperature and the highest stripping flux was obtained in the temperature of 90 °C. The enhancement of the gas flow rate increased the CO 2 desorption flux but this change was negligible.

  • effect of polymer concentration on the structure and performance of pei hollow fiber membrane contactor for co2 stripping
    Journal of Hazardous Materials, 2013
    Co-Authors: R. Naim, A F Ismail
    Abstract:

    A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13–16 wt.%) for CO2 stripping process in membrane contactor application was fabricated via wet phase inversion method. The PEI membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated via membrane contactor system in a stainless steel module with aqueous diethanolamine as liquid absorbent. The hollow fiber membranes showed decreasing patterns in gas permeation, contact angle, mean pore size and effective surface porosity with increasing polymer concentration. On the contrary, wetting pressure of PEI membranes has enhanced significantly with polymer concentration. Various polymer concentrations have different effects on the CO2 stripping flux in which membrane with 14 wt.% polymer concentration showed the highest stripping flux of 2.7 × 10−2 mol/m2 s. From the performance comparison with other commercial membrane, it is anticipated that the PEI membrane has a good prospect in CO2 stripping via membrane contactor.

  • effect of polymer concentration on the structure and performance of pei hollow fiber membrane contactor for co2 stripping
    Journal of Hazardous Materials, 2013
    Co-Authors: R. Naim, A F Ismail
    Abstract:

    A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13–16 wt.%) for CO2 stripping process in membrane contactor application was fabricated via wet phase inversion method. The PEI membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated via membrane contactor system in a stainless steel module with aqueous diethanolamine as liquid absorbent. The hollow fiber membranes showed decreasing patterns in gas permeation, contact angle, mean pore size and effective surface porosity with increasing polymer concentration. On the contrary, wetting pressure of PEI membranes has enhanced significantly with polymer concentration. Various polymer concentrations have different effects on the CO2 stripping flux in which membrane with 14 wt.% polymer concentration showed the highest stripping flux of 2.7 × 10−2 mol/m2 s. From the performance comparison with other commercial membrane, it is anticipated that the PEI membrane has a good prospect in CO2 stripping via membrane contactor.

  • carbon dioxide stripping from diethanolamine solution through porous surface modified pvdf hollow fiber membrane contactor
    Journal of Membrane Science, 2013
    Co-Authors: A F Ismail, Dipak Rana, Masoud Rahbarisisakht, Takeshi Matsuura
    Abstract:

    Abstract Porous asymmetric polyvinylidene fluoride (PVDF) hollow fiber membrane were fabricated via a phase-inversion method using surface modifying macromolecules (SMM) (1 wt%) as the additive in the spinning dope. Distilled water and tap water were used as internal and external coagulation bath, respectively. The membranes were characterized in terms of gas permeation, wetting resistance, overall porosity, contact angle and collapsing pressure. CO2 stripping from diethanolamine (DEA) solutions was conducted through the gas–liquid membrane contactor. The effect of some operating conditions such as gas and liquid velocities, DEA concentration and rich solution temperature on the CO2 stripping flux and efficiency were investigated. By increasing liquid flow rate to 200 ml.min−1, the maximum CO2 stripping efficiency of almost 82% was achieved. In addition, an increase in the liquid flow rate resulted in a significant increase of CO2 stripping flux. By increasing the liquid flow rate from 50 to 200 ml min−1, the CO2 flux increased by 900%. By increasing the gas velocity the CO2 desorption flux increased but this changing was negligible. The effect of rich solution temperature was investigated and the results showed that the CO2 desorption flux increased with increasing the solution temperature from 80 to 90 °C. The results of DEA concentration enhancement on the CO2 desorption flux showed that the CO2 stripping flux increased drastically with enrichment of the DEA concentration from 1.0 to 3.0 (mol l−1). Therefore, the higher stripping efficiency can be achieved by applying the higher liquid flow rate, temperature and DEA concentration in the absorbent liquid in the membrane contactor module.

R. Naim - One of the best experts on this subject based on the ideXlab platform.

  • polyvinylidene fluoride and polyetherimide hollow fiber membranes for co2 stripping in membrane contactor
    Chemical Engineering Research & Design, 2014
    Co-Authors: R. Naim, A F Ismail, Ng Be Cheer, Mohd Sohaimi Abdullah
    Abstract:

    Porous polyvinylidene fluoride (PVDF) and polyetherimide (PEI) hollow fiber membranes incorporating polyethylene glycol (PEG) were prepared via spinning process for CO2 membrane stripping. CO2 loaded diethanolamine solution was used as liquid absorbent while N2 was used as a strip gas. The characterization study of the fibers was carried out in terms of permeation test, contact angle measurement and liquid entry pressure (wetting pressure). Performance study via membrane contactor stripping was carried out at specific operating condition. The experimental results showed that PVDF membrane have high gas permeation, effective surface porosity and contact angle despite having lower liquid entry pressure in comparison with PEI membrane. PVDF-PEG membrane showed the highest stripping flux of 4.0 × 10−2 mol m−2 s−1 at 0.7 ms−1 compared to that of PEI membrane. Although the stripping flux for PEI-PEG membranes was slightly lower than PVDF membrane (e.g. 3.5 × 10−2 mol m−2 s−1 at liquid velocity of 0.85 ms−1), the membrane wetting pressure of PEI membrane is higher than hydrophobic PVDF membrane. Long term performance of both membranes showed severe flux reduction but started to level-off after 30 h of operation.

  • effect of polymer concentration on the structure and performance of pei hollow fiber membrane contactor for co2 stripping
    Journal of Hazardous Materials, 2013
    Co-Authors: R. Naim, A F Ismail
    Abstract:

    A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13–16 wt.%) for CO2 stripping process in membrane contactor application was fabricated via wet phase inversion method. The PEI membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated via membrane contactor system in a stainless steel module with aqueous diethanolamine as liquid absorbent. The hollow fiber membranes showed decreasing patterns in gas permeation, contact angle, mean pore size and effective surface porosity with increasing polymer concentration. On the contrary, wetting pressure of PEI membranes has enhanced significantly with polymer concentration. Various polymer concentrations have different effects on the CO2 stripping flux in which membrane with 14 wt.% polymer concentration showed the highest stripping flux of 2.7 × 10−2 mol/m2 s. From the performance comparison with other commercial membrane, it is anticipated that the PEI membrane has a good prospect in CO2 stripping via membrane contactor.

  • effect of polymer concentration on the structure and performance of pei hollow fiber membrane contactor for co2 stripping
    Journal of Hazardous Materials, 2013
    Co-Authors: R. Naim, A F Ismail
    Abstract:

    A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13–16 wt.%) for CO2 stripping process in membrane contactor application was fabricated via wet phase inversion method. The PEI membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated via membrane contactor system in a stainless steel module with aqueous diethanolamine as liquid absorbent. The hollow fiber membranes showed decreasing patterns in gas permeation, contact angle, mean pore size and effective surface porosity with increasing polymer concentration. On the contrary, wetting pressure of PEI membranes has enhanced significantly with polymer concentration. Various polymer concentrations have different effects on the CO2 stripping flux in which membrane with 14 wt.% polymer concentration showed the highest stripping flux of 2.7 × 10−2 mol/m2 s. From the performance comparison with other commercial membrane, it is anticipated that the PEI membrane has a good prospect in CO2 stripping via membrane contactor.

  • effect of non solvent additives on the structure and performance of pvdf hollow fiber membrane contactor for co2 stripping
    Journal of Membrane Science, 2012
    Co-Authors: R. Naim, A F Ismail, Amir Mansourizadeh
    Abstract:

    Microporous polyvinylidene fluoride (PVDF) hollow fiber membranes with various non-solvent additives, i.e. lithium chloride, glycerol, polyethylene glycol (PEG-400), methanol and phosphoric acid, were fabricated for CO2 stripping via membrane contactors. The membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated by using an in-house made stainless steel module with CO2-preloaded aqueous diethanolamine as the liquid absorbent. Hydrophobicity and gas permeability of the membranes reduced with the addition of a non-solvent additive in the polymer dope but increase in liquid entry pressure was observed as more sponge-like structures developed in the inner layer of the fibers. It was found that PVDF/PEG-400 membrane produced the highest stripping flux of 4.03×10−2 mol m−2 s−1 which can be correlated to its high gas permeation and high effective surface porosity. The result of long-term stripping operation indicated an approximatly 80% stripping flux reduction which can be related to the interaction of polymer membrane and amine solution at high temperature.

  • preparation of microporous pvdf hollow fiber membrane contactors for co2 stripping from diethanolamine solution
    Journal of Membrane Science, 2012
    Co-Authors: R. Naim, A F Ismail, Amir Mansourizadeh
    Abstract:

    Abstract Microporous polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via a wet-spinning process. The prepared fibers were characterized in terms of contact angle, gas permeability, wetting pressure and morphology. CO2 stripping from preloaded aqueous diethanolamine solution was conducted through the gas–liquid membrane contactors. The effects of lithium chloride (LiCl) concentration on the membrane properties and CO2 stripping performance were investigated. The addition of different LiCl concentration resulted in a less finger-like structure, with highly effective surface porosity and high wetting pressure. Conversely, N2 permeability, contact angle value and membrane pore size were reduced as the concentration of the additives were increased. For stripping flux performance, membrane with 5 wt% LiCl demonstrated the highest flux of 1.61 × 10−2 mol/m2 s at 110 ml/min of the liquid flow rate. It was found that the membrane with less finger-like structure and higher effective surface porosity exhibited higher stripping efficiency. These results suggest that developed membrane structure can be an alternative for the CO2 stripping through gas–liquid membrane contactors.

Amir Mansourizadeh - One of the best experts on this subject based on the ideXlab platform.

  • effect of non solvent additives on the structure and performance of pvdf hollow fiber membrane contactor for co2 stripping
    Journal of Membrane Science, 2012
    Co-Authors: R. Naim, A F Ismail, Amir Mansourizadeh
    Abstract:

    Microporous polyvinylidene fluoride (PVDF) hollow fiber membranes with various non-solvent additives, i.e. lithium chloride, glycerol, polyethylene glycol (PEG-400), methanol and phosphoric acid, were fabricated for CO2 stripping via membrane contactors. The membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated by using an in-house made stainless steel module with CO2-preloaded aqueous diethanolamine as the liquid absorbent. Hydrophobicity and gas permeability of the membranes reduced with the addition of a non-solvent additive in the polymer dope but increase in liquid entry pressure was observed as more sponge-like structures developed in the inner layer of the fibers. It was found that PVDF/PEG-400 membrane produced the highest stripping flux of 4.03×10−2 mol m−2 s−1 which can be correlated to its high gas permeation and high effective surface porosity. The result of long-term stripping operation indicated an approximatly 80% stripping flux reduction which can be related to the interaction of polymer membrane and amine solution at high temperature.

  • experimental study of co2 absorption stripping via pvdf hollow fiber membrane contactor
    Chemical Engineering Research & Design, 2012
    Co-Authors: Amir Mansourizadeh
    Abstract:

    Abstract Gas–liquid hollow fiber membrane contactor can be a promising alternative for the CO 2 absorption/stripping due to the advantages over traditional contacting devices. In this study, the structurally developed hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes were prepared via a wet spinning method. The membranes were characterized in terms of morphology, permeability, wetting resistance, overall porosity and mass transfer resistance. From the morphology analysis, the membranes demonstrated a thin outer finger-like layer with ultra thin skin and a thick inner sponge-like layer without skin. The characterization results indicated that the membranes possess a mean pore size of 9.6 nm with high permeability and wetting resistance and low mass transfer resistance (1.2 × 10 4  s/m). Physical CO 2 absorption/stripping were conducted through the fabricated gas–liquid membrane contactor modules, where distilled water was used as the liquid absorbent. The liquid phase resistance was dominant due to significant change in the absorption/stripping flux with the liquid velocity. The CO 2 absorption flux was approximately 10 times higher than the CO 2 stripping flux at the same operating condition due to high solubility of CO 2 in water as confirmed with the effect of liquid phase pressure and temperature on the absorption/stripping flux.

  • preparation of microporous pvdf hollow fiber membrane contactors for co2 stripping from diethanolamine solution
    Journal of Membrane Science, 2012
    Co-Authors: R. Naim, A F Ismail, Amir Mansourizadeh
    Abstract:

    Abstract Microporous polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via a wet-spinning process. The prepared fibers were characterized in terms of contact angle, gas permeability, wetting pressure and morphology. CO2 stripping from preloaded aqueous diethanolamine solution was conducted through the gas–liquid membrane contactors. The effects of lithium chloride (LiCl) concentration on the membrane properties and CO2 stripping performance were investigated. The addition of different LiCl concentration resulted in a less finger-like structure, with highly effective surface porosity and high wetting pressure. Conversely, N2 permeability, contact angle value and membrane pore size were reduced as the concentration of the additives were increased. For stripping flux performance, membrane with 5 wt% LiCl demonstrated the highest flux of 1.61 × 10−2 mol/m2 s at 110 ml/min of the liquid flow rate. It was found that the membrane with less finger-like structure and higher effective surface porosity exhibited higher stripping efficiency. These results suggest that developed membrane structure can be an alternative for the CO2 stripping through gas–liquid membrane contactors.

  • co2 stripping from water through porous pvdf hollow fiber membrane contactor
    Desalination, 2011
    Co-Authors: Amir Mansourizadeh, A F Ismail
    Abstract:

    Abstract Porous polyvinylidene fluoride (PVDF) hollow fiber membranes were prepared via wet spinning process. The membranes were characterized in terms of gas permeation, wetting resistance and overall porosity, which are important parameters for gas absorption/stripping applications. CO2 stripping from water was conducted through the gas–liquid membrane contactor. The effect of different operating conditions on the CO2 stripping efficiency of the membrane was investigated. The results indicated a significant improvement in the CO2 stripping efficiency by increasing the liquid phase temperature. On the other hand, increasing the liquid flow rate resulted in a considerable decrease in the CO2 stripping flux. The maximum stripping efficiency of 32% was achieved at 60 ml/min of the liquid flow rate, 60 °C and 0.5 × 105 Pa. It was found that the liquid phase temperature, the gas–liquid contact area and contact time are the key parameters for enhancement of CO2 stripping efficiency.

B Vollmer - One of the best experts on this subject based on the ideXlab platform.

  • two uneven sisters i ngc 4388 a strongly constrained ram pressure stripping event
    Astronomy and Astrophysics, 2018
    Co-Authors: B Vollmer, C Pappalardo, M Soida, Ariane Lancon
    Abstract:

    Since the Virgo cluster is the closest galaxy cluster in the northern hemisphere, galaxy interactions can be observed in it with a kpc resolution. The spiral galaxy NGC 4388 underwent a ram pressure stripping event ~200 Myr ago caused by its highly eccentric orbit within the Virgo cluster. This galaxy fulfills all diagnostic criteria for having undergone active ram pressure stripping in the recent past: a strongly truncated HI and Halpha disk, an asymmetric ridge of polarized radio continuum emission, extended extraplanar gas toward the opposite side of the ridge of polarized radio continuum emission, and a recent (a few 100 Myr) quenching of the star formation activity in the outer, gas-free galactic disk. We made dynamical simulations of the ram pressure stripping event to investigate the influence of galactic structure on the observed properties of NGC 4388. The combination of a deep optical spectrum of the outer gas-free region of the galactic disk together with deep HI, Halpha, FUV, and polarized radio continuum data permits to constrain numerical simulations to derive the temporal ram pressure profile, the 3D velocity vector of the galaxy, and the time since peak ram pressure with a high level of confidence. From the simulations an angle between the ram pressure wind and the galactic disk of 30 degrees is derived. The galaxy underwent peak ram pressure ~240 Myr ago. The observed asymmetries in the disk of NGC 4388 are not caused by the present action of ram pressure, but by the resettling of gas that has been pushed out of the galactic disk during the ram pressure stripping event. For the detailed reproduction of multi-wavelength observations of a spiral galaxy that undergoes or underwent a ram pressure stripping event, galactic structure, i.e. spiral arms, has to be taken into account.

  • the effect of ram pressure on the molecular gas of galaxies three case studies in the virgo cluster
    Monthly Notices of the Royal Astronomical Society, 2017
    Co-Authors: Bumhyun Lee, B Vollmer, Aeree Chung, Stephanie Tonnesen, Jeffrey D P Kenney, Ivy O Wong, G Petitpas, H Crowl, Jacqueline Van Gorkom
    Abstract:

    We present 12CO (2-1) data of three Virgo spirals - NGC 4330, NGC 4402 and NGC 4522 obtained using the Submillimeter Array. These three galaxies show clear evidence of ram pressure stripping due to the cluster medium as found in previous HI imaging studies. Using high-resolution CO data, we investigate how the properties of the inner molecular gas disc change while a galaxy is undergoing HI stripping in the cluster. At given sensitivity limits, we do not find any clear signs of molecular gas stripping. However, both its morphology and kinematics appear to be quite disturbed as those of HI. Morphological peculiarities present in the molecular and atomic gas are closely related with each other, suggesting that molecular gas can be also affected by strong ICM pressure even if it is not stripped. CO is found to be modestly enhanced along the upstream sides in these galaxies, which may change the local star formation activity in the disc. Indeed, the distribution of H$\alpha$ emission, a tracer of recent star formation, well coincides with that of the molecular gas, revealing enhancements near the local CO peak or along the CO compression. FUV and H$\alpha$ share some properties in common, but FUV is always more extended than CO/H$\alpha$ in the three galaxies, implying that the star-forming disc is rapidly shrinking as the molecular gas properties have changed. We discuss how ICM pressure affects dense molecular gas and hence star formation properties while diffuse atomic gas is being removed from a galaxy.

  • ngc 4569 recent evidence for a past ram pressure stripping event
    Astronomy and Astrophysics, 2004
    Co-Authors: B Vollmer, C Balkowski, V Cayatte, Wim Van Driel, W K Huchtmeier
    Abstract:

    Deep 21-cm H i line observations of the Virgo cluster spiral galaxy NGC 4569 have been obtained with the VLA in its D configuration and with the Effelsberg 100-m telescope. A low surface density arm was discovered in the west of the galaxy, whose velocity field is distinct from that of the overall disk rotation. The observed gas distribution, velocity field and velocity dispersion are compared to snapshots of dynamical simulations that include the effects of ram pressure. Two different scenarios were explored: (i) ongoing stripping and (ii) a major stripping event that took place about 300 Myr ago. It is concluded that only the post–stripping scenario can reproduce the main observed characteristics of NGC 4569. It is not possible to determine if the gas disk of NGC 4569 had already been truncated before it underwent the ram pressure event that lead to its observed H i deficiency.

  • ngc 4654 gravitational interaction or ram pressure stripping
    Astronomy and Astrophysics, 2003
    Co-Authors: B Vollmer
    Abstract:

    The Virgo cluster spiral galaxy NGC 4654 is supposed to be a good candidate for ongoing ram pressure stripping based on its very asymmetric Hi distribution. However, this galaxy also shows an asymmetric stellar distribution. Numerical simulations using ram pressure as the only perturbation can produce a tail structure of the gas content, but cannot account for its kinematical structure. It is shown that a strong edge-on stripping event can produce an asymmetric stellar distribution up to 800 Myr after the stripping event, i.e. the galaxy's closest passage to the cluster center. Simulations using a gravitational interaction with the companion galaxy NGC 4639 can account for the asymmetric stellar distribution of NGC 4654, but cannot reproduce the observed extended gas tail. Only a mixed interaction, gravitational and ram pressure, can reproduce all observed properties of NGC 4654. It is concluded that NGC 4654 had a tidal interaction ∼500 Myr ago and is continuing to experience ram pressure until the present day.

  • ngc 4654 gravitational interaction or ram pressure stripping
    arXiv: Astrophysics, 2002
    Co-Authors: B Vollmer
    Abstract:

    The Virgo cluster spiral galaxy NGC 4654 is supposed to be a good candidate for ongoing ram pressure stripping based on its very asymmetric HI distribution. However, this galaxy also shows an asymmetric stellar distribution. Numerical simulations using ram pressure as the only perturbation can produce a tail structure of the gas content, but cannot account for its kinematical structure. It is shown that a strong edge-on stripping event can produce an asymmetric stellar distribution up to 800 Myr after the stripping event, i.e. the galaxy's closest passage to the cluster center. Simulations using a gravitational interaction with the companion galaxy NGC 4639 can account for the asymmetric stellar distribution of NGC 4654, but cannot reproduce the observed extended gas tail. Only a mixed interaction, gravitational and ram pressure, can reproduce all observed properties of NGC 4654. It is concluded that NGC 4654 had a tidal interaction ~500 Myr ago and is continuing to experience ram pressure.

Yoshimori Miyano - One of the best experts on this subject based on the ideXlab platform.