The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform
Takeshi Matsuura - One of the best experts on this subject based on the ideXlab platform.
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influence of air gap length on co2 stripping from diethanolamine solution and water performance of Surface modified pvdf hollow fiber membrane contactor
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2018Co-Authors: Masoud Rahbarisisakht, Ahmad Fauzi Ismail, Takeshi Matsuura, Daryoush Emadzadeh, Fatemeh Korminouri, Alireza MayahiAbstract:Surface Modifying Macromolecule (SMM) blended PVDF hollow fibers (HFs) were spun at different air-gaps (o to 20 cm) and used for CO2 stripping from aqueous DEA solution and water. The manufactured fibers were firstly subjected to various characterization tests such as contact angle and critical water entry pressure measurement to evaluate the HF hydrophobicity and wetting resistance, respectively. The pure helium permeation experiments were also conducted to obtain membrane pore size and effective porosity. Morphology of the HFs was investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The SEM images showed that both outer and inner diameters of HFs decreased significantly by increasing air-gap length which mainly because of elongation of HF caused by gravity while travelling through the air-gap. Also, the gradual decrease in roughness on the external Surface of the produced HFs was observed from the AFM images. It was found that the increase of liquid velocity enhances the CO2 stripping flux. It was found that 10 cm air-gap gave maximum stripping flux of 3.34 x 10(-2) and 1.34 x 10(-3) (mol/m(2)s) for DEA solution and water, respectively. The increase in gas velocity, on the other hand, did not affect the stripping flux significantly. It was observed that the increase of temperature from 25 to 80 degrees C led to the marked enhancement of stripping flux from 6.30 x 10(-3) to 3.34 x 10(-2) (mol/m(2)s) and 6.5 x 10(-5) to 1.34 x 10(-3) (mol/m(2)s), for DEA solution and water, respectively. Furthermore, the increase in DEA concentration from 0.25 to 1 mol/L, led to the enhancement of the stripping flux from 6.84 x 10(-3) to 3.34 x 10(-2) (mol/m(2)s) at a liquid velocity of 0.7 m/s. It was concluded that the HF spun at 10 cm air-gap exhibited the best stripping performance among all fabricated HFs.
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Preparation and Characterization of Blending Sulfonated Poly(ether ether ketone) with Charged Surface Modifying Macromolecules
Journal of Applied Membrane Science & Technology, 2017Co-Authors: M.n.a. Mohd Norddin, Takeshi Matsuura, A.f. Ismail, Dipak RanaAbstract:Charged Surface Modifying Macromolecule (cSMM) end capped with sulfonic group was prepared and blended into sulfonated poly(ether ether ketone) (SPEEK). The modified membrane was characterized for polymer electrolyte membrane application; i.e. a SPEEK/cSMM blend membrane was compared to a SPEEK membrane and a Nafion 112 membrane for the thermal and mechanical stability, hydrophilicity and water uptake. Thermal and mechanical stability of the blend membrane were slightly reduced from that of the SPEEK membrane but still higher than that of the Nafion 112 membrane. The cSMM which was end–capped with sulfonic group has increased the total –SO3H group in the blend membrane. As a result, the blend membrane showed an increase in hydrophilicity and water uptake as compared to the pristine membrane. The addition of cSMM with an additional –SO 3 – charge has enabled the water uptake to be increased which is crucial to enhance the proton conductivity that of SPEEK. Moreover, the extra –SO 3 – can facilitate the transfer of proton better. This study found that cSMM is a good candidate as an additive for SPEEK in improving its function as polymer electrolyte membrane.
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Separation of macromolecular proteins and rejection of toxic heavy metal ions by PEI/cSMM blend UF membranes
International journal of biological macromolecules, 2014Co-Authors: P. Kanagaraj, Takeshi Matsuura, Dipak Rana, Alagumalai Nagendran, S. NeelakandanAbstract:Abstract The charged Surface Modifying Macromolecule (cSMM) was blended into the casting solution of poly(ether imide) (PEI) to prepare Surface modified ultrafiltration membranes by phase inversion technique. The separation of proteins including bovine serum albumin, egg albumin, pepsin and trypsin was investigated by the fabricated membranes. On increasing cSMM content, solute rejection decreases whereas membrane flux increases. The pore size and Surface porosity of the 5 wt% cSMM blend PEI membranes increases to 41.4 A and 14.8%, respectively. Similarly, the molecular weight cut-off of the membranes ranged from 20 to 45 kDa, depending on the various compositions of the prepared membranes. The toxic heavy metal ions Cu(II), Cr(III), Zn(II) and Pb(II) from aqueous solutions were subjected to rejection by the prepared blended membrane with various concentration of polyethyleneimine (PETIM) as water soluble polymeric ligand. It was found that the rejection behavior of metal ion depends on the PETIM concentration and the stability complexation of metal ion with ligand.
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blend polyvinylidene fluoride Surface Modifying Macromolecule hollow fiber membrane contactors for co2 absorption
International Journal of Greenhouse Gas Control, 2014Co-Authors: Amir Mansourizadeh, Ahmad Fauzi Ismail, Z. Aslmahdavi, Takeshi MatsuuraAbstract:Abstract Recently, membrane contactors have attracted attentions as an efficient and flexible technology for CO 2 capture. In the present work, blend hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes were prepared via a dry–wet phase-inversion process. Surface Modifying Macromolecule (SMM) was introduced to improve the membrane properties for CO 2 absorption in gas–liquid membrane contactors. The effect of SMM concentration in the polymer dope, air gap distance and bore fluid composition on the structure and performance of the membranes were investigated. By increasing SMM in the polymer dope, the membranes presented smaller mean pore sizes, higher permeability and Surface hydrophobicity. Using 2 wt.% SMM, the membranes prepared at 24 cm air gap showed larger mean pore size, higher hydrophobicity and lower permeability compared to those prepared at 0 cm air gap. By using 60 wt.% DMAc aqueous solution as the bore fluid, the membrane permeability and CO 2 flux significantly improved. Maximum CO 2 absorption flux of 6.8 × 10 −4 mol/m 2 s was achieved at absorbent velocity of 0.025 m/s. The Surface modified membrane demonstrated about 10% gradual CO 2 flux reduction for over 140 h of the long-term operation. In conclusion, by improving Surface hydrophobicity of the membrane, a long-term stable operation can be achieved for practical implication of gas–liquid membrane contactor technology.
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Blend polyvinylidene fluoride/Surface Modifying Macromolecule hollow fiber membrane contactors for CO2 absorption
International Journal of Greenhouse Gas Control, 2014Co-Authors: Amir Mansourizadeh, Ahmad Fauzi Ismail, Z. Aslmahdavi, Takeshi MatsuuraAbstract:Abstract Recently, membrane contactors have attracted attentions as an efficient and flexible technology for CO 2 capture. In the present work, blend hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes were prepared via a dry–wet phase-inversion process. Surface Modifying Macromolecule (SMM) was introduced to improve the membrane properties for CO 2 absorption in gas–liquid membrane contactors. The effect of SMM concentration in the polymer dope, air gap distance and bore fluid composition on the structure and performance of the membranes were investigated. By increasing SMM in the polymer dope, the membranes presented smaller mean pore sizes, higher permeability and Surface hydrophobicity. Using 2 wt.% SMM, the membranes prepared at 24 cm air gap showed larger mean pore size, higher hydrophobicity and lower permeability compared to those prepared at 0 cm air gap. By using 60 wt.% DMAc aqueous solution as the bore fluid, the membrane permeability and CO 2 flux significantly improved. Maximum CO 2 absorption flux of 6.8 × 10 −4 mol/m 2 s was achieved at absorbent velocity of 0.025 m/s. The Surface modified membrane demonstrated about 10% gradual CO 2 flux reduction for over 140 h of the long-term operation. In conclusion, by improving Surface hydrophobicity of the membrane, a long-term stable operation can be achieved for practical implication of gas–liquid membrane contactor technology.
Ahmad Fauzi Ismail - One of the best experts on this subject based on the ideXlab platform.
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influence of air gap length on co2 stripping from diethanolamine solution and water performance of Surface modified pvdf hollow fiber membrane contactor
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2018Co-Authors: Masoud Rahbarisisakht, Ahmad Fauzi Ismail, Takeshi Matsuura, Daryoush Emadzadeh, Fatemeh Korminouri, Alireza MayahiAbstract:Surface Modifying Macromolecule (SMM) blended PVDF hollow fibers (HFs) were spun at different air-gaps (o to 20 cm) and used for CO2 stripping from aqueous DEA solution and water. The manufactured fibers were firstly subjected to various characterization tests such as contact angle and critical water entry pressure measurement to evaluate the HF hydrophobicity and wetting resistance, respectively. The pure helium permeation experiments were also conducted to obtain membrane pore size and effective porosity. Morphology of the HFs was investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The SEM images showed that both outer and inner diameters of HFs decreased significantly by increasing air-gap length which mainly because of elongation of HF caused by gravity while travelling through the air-gap. Also, the gradual decrease in roughness on the external Surface of the produced HFs was observed from the AFM images. It was found that the increase of liquid velocity enhances the CO2 stripping flux. It was found that 10 cm air-gap gave maximum stripping flux of 3.34 x 10(-2) and 1.34 x 10(-3) (mol/m(2)s) for DEA solution and water, respectively. The increase in gas velocity, on the other hand, did not affect the stripping flux significantly. It was observed that the increase of temperature from 25 to 80 degrees C led to the marked enhancement of stripping flux from 6.30 x 10(-3) to 3.34 x 10(-2) (mol/m(2)s) and 6.5 x 10(-5) to 1.34 x 10(-3) (mol/m(2)s), for DEA solution and water, respectively. Furthermore, the increase in DEA concentration from 0.25 to 1 mol/L, led to the enhancement of the stripping flux from 6.84 x 10(-3) to 3.34 x 10(-2) (mol/m(2)s) at a liquid velocity of 0.7 m/s. It was concluded that the HF spun at 10 cm air-gap exhibited the best stripping performance among all fabricated HFs.
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SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell
Journal of Chemical Technology & Biotechnology, 2015Co-Authors: Alireza Mayahi, Ahmad Fauzi Ismail, Juhana Jaafar, Masoud Rahbari-sisakht, Hamid Ilbeygi, Wan Ramli Wan Daud, Daryoush Emadzadeh, Ezzatollah Shamsaei, Darren J. Martin, Mostafa GhasemiAbstract:Sulfonated poly (ether ether ketone) (SPEEK) membranes and their modifications are viewed as arguably the most promising in microbial fuel cell (MFC) applications due to their non-fluorinated base, superior chemical stability, and lower costs compared with Nafion membranes. In this work, SPEEK membranes with different degrees of sulfonation (DSs) (60% to 76%) and blended with charged Surface Modifying Macromolecule (cSMM) were used as electrolytes in an MFC for simultaneous electricity generation and wastewater treatment. RESULTS: Performance evaluation of newly fabricated membranes was carried out and was compared with that of Nafion 117. The MFC with SPEEK76/cSMM generated about 16.5% higher maximum power density (172.1 mW m-2) than that with Nafion 117 (143.7 mW m-2). In addition, the SPEEK76/cSMM exhibited the highest coulombic efficiency (CE) of 17.6%, which was 21.6% higher than that of Nafion 117 (13.8%). Chemical oxygen demand (COD) removal of all characterized membranes was above 80% in our particular MFC. CONCLUSION: MFC is a suitable method for simultaneous wastewater treatment and electricity generation. SPEEK76/cSMM is a promising membrane to be applied in MFC. © 2014 Society of Chemical Industry.
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blend polyvinylidene fluoride Surface Modifying Macromolecule hollow fiber membrane contactors for co2 absorption
International Journal of Greenhouse Gas Control, 2014Co-Authors: Amir Mansourizadeh, Ahmad Fauzi Ismail, Z. Aslmahdavi, Takeshi MatsuuraAbstract:Abstract Recently, membrane contactors have attracted attentions as an efficient and flexible technology for CO 2 capture. In the present work, blend hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes were prepared via a dry–wet phase-inversion process. Surface Modifying Macromolecule (SMM) was introduced to improve the membrane properties for CO 2 absorption in gas–liquid membrane contactors. The effect of SMM concentration in the polymer dope, air gap distance and bore fluid composition on the structure and performance of the membranes were investigated. By increasing SMM in the polymer dope, the membranes presented smaller mean pore sizes, higher permeability and Surface hydrophobicity. Using 2 wt.% SMM, the membranes prepared at 24 cm air gap showed larger mean pore size, higher hydrophobicity and lower permeability compared to those prepared at 0 cm air gap. By using 60 wt.% DMAc aqueous solution as the bore fluid, the membrane permeability and CO 2 flux significantly improved. Maximum CO 2 absorption flux of 6.8 × 10 −4 mol/m 2 s was achieved at absorbent velocity of 0.025 m/s. The Surface modified membrane demonstrated about 10% gradual CO 2 flux reduction for over 140 h of the long-term operation. In conclusion, by improving Surface hydrophobicity of the membrane, a long-term stable operation can be achieved for practical implication of gas–liquid membrane contactor technology.
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Blend polyvinylidene fluoride/Surface Modifying Macromolecule hollow fiber membrane contactors for CO2 absorption
International Journal of Greenhouse Gas Control, 2014Co-Authors: Amir Mansourizadeh, Ahmad Fauzi Ismail, Z. Aslmahdavi, Takeshi MatsuuraAbstract:Abstract Recently, membrane contactors have attracted attentions as an efficient and flexible technology for CO 2 capture. In the present work, blend hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes were prepared via a dry–wet phase-inversion process. Surface Modifying Macromolecule (SMM) was introduced to improve the membrane properties for CO 2 absorption in gas–liquid membrane contactors. The effect of SMM concentration in the polymer dope, air gap distance and bore fluid composition on the structure and performance of the membranes were investigated. By increasing SMM in the polymer dope, the membranes presented smaller mean pore sizes, higher permeability and Surface hydrophobicity. Using 2 wt.% SMM, the membranes prepared at 24 cm air gap showed larger mean pore size, higher hydrophobicity and lower permeability compared to those prepared at 0 cm air gap. By using 60 wt.% DMAc aqueous solution as the bore fluid, the membrane permeability and CO 2 flux significantly improved. Maximum CO 2 absorption flux of 6.8 × 10 −4 mol/m 2 s was achieved at absorbent velocity of 0.025 m/s. The Surface modified membrane demonstrated about 10% gradual CO 2 flux reduction for over 140 h of the long-term operation. In conclusion, by improving Surface hydrophobicity of the membrane, a long-term stable operation can be achieved for practical implication of gas–liquid membrane contactor technology.
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Effect of air-gap length on carbon dioxide stripping performance of a Surface modified polysulfone hollow fiber membrane contactor
RSC Adv., 2014Co-Authors: Masoud Rahbari-sisakht, Takeshi Matsuura, Daryoush Emadzadeh, Fatemeh Korminouri, Ahmad Fauzi IsmailAbstract:Surface Modifying Macromolecule (SMM) blended PSf hollow fibers were spun at different air-gaps to evaluate CO2 stripping from aqueous DEA solution and water. The fabricated membranes were firstly subjected to different characterization methods such as contact angle and liquid entry pressure measurement to evaluate the membrane's hydrophobicity and wetting resistance, respectively. To determine pore size and effective porosity of the membranes, a pure helium permeation test was performed. Morphological study of the membranes was conducted by scanning electron microscopy (SEM) and atomic force microscopy (AFM). A CO2 stripping test was carried out to investigate the effects of operating variables such as liquid and gas velocity, temperature and DEA concentration on the CO2 stripping flux. It was found that the increase of liquid velocity resulted in enhanced CO2 stripping flux. On the other hand, the increase in gas velocity did not exert significant influence on the stripping flux. The increase in temperature and DEA concentration both enhanced the stripping flux. Lastly, it was concluded that the hollow fibers spun in this work at a 15 cm air-gap could achieve the best stripping flux among all the membranes fabricated so far for CO2 stripping.
Dipak Rana - One of the best experts on this subject based on the ideXlab platform.
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Preparation and Characterization of Blending Sulfonated Poly(ether ether ketone) with Charged Surface Modifying Macromolecules
Journal of Applied Membrane Science & Technology, 2017Co-Authors: M.n.a. Mohd Norddin, Takeshi Matsuura, A.f. Ismail, Dipak RanaAbstract:Charged Surface Modifying Macromolecule (cSMM) end capped with sulfonic group was prepared and blended into sulfonated poly(ether ether ketone) (SPEEK). The modified membrane was characterized for polymer electrolyte membrane application; i.e. a SPEEK/cSMM blend membrane was compared to a SPEEK membrane and a Nafion 112 membrane for the thermal and mechanical stability, hydrophilicity and water uptake. Thermal and mechanical stability of the blend membrane were slightly reduced from that of the SPEEK membrane but still higher than that of the Nafion 112 membrane. The cSMM which was end–capped with sulfonic group has increased the total –SO3H group in the blend membrane. As a result, the blend membrane showed an increase in hydrophilicity and water uptake as compared to the pristine membrane. The addition of cSMM with an additional –SO 3 – charge has enabled the water uptake to be increased which is crucial to enhance the proton conductivity that of SPEEK. Moreover, the extra –SO 3 – can facilitate the transfer of proton better. This study found that cSMM is a good candidate as an additive for SPEEK in improving its function as polymer electrolyte membrane.
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Separation of macromolecular proteins and rejection of toxic heavy metal ions by PEI/cSMM blend UF membranes
International journal of biological macromolecules, 2014Co-Authors: P. Kanagaraj, Takeshi Matsuura, Dipak Rana, Alagumalai Nagendran, S. NeelakandanAbstract:Abstract The charged Surface Modifying Macromolecule (cSMM) was blended into the casting solution of poly(ether imide) (PEI) to prepare Surface modified ultrafiltration membranes by phase inversion technique. The separation of proteins including bovine serum albumin, egg albumin, pepsin and trypsin was investigated by the fabricated membranes. On increasing cSMM content, solute rejection decreases whereas membrane flux increases. The pore size and Surface porosity of the 5 wt% cSMM blend PEI membranes increases to 41.4 A and 14.8%, respectively. Similarly, the molecular weight cut-off of the membranes ranged from 20 to 45 kDa, depending on the various compositions of the prepared membranes. The toxic heavy metal ions Cu(II), Cr(III), Zn(II) and Pb(II) from aqueous solutions were subjected to rejection by the prepared blended membrane with various concentration of polyethyleneimine (PETIM) as water soluble polymeric ligand. It was found that the rejection behavior of metal ion depends on the PETIM concentration and the stability complexation of metal ion with ligand.
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Development of novel charged Surface Modifying Macromolecule blended PES membranes to remove EDCs and PPCPs from drinking water sources
J. Mater. Chem. A, 2014Co-Authors: Dipak Rana, Takeshi Matsuura, Roberto M Narbaitz, Shahram Tabe, Anne-marie Garand-sheridan, Amy Westgate, Saad JasimAbstract:The aim of this study was to develop novel Surface-modified poly(ether sulfone) (PES) ultra-filtration (UF) membranes for removal of endocrine disrupting chemicals (EDCs) and pharmaceutical and personal care products (PPCPs). Seven tailor-made charged Surface Modifying Macromolecules (CSMMs) were developed for use as additives in the preparation of PES UF membranes with a greater Surface charge and improved PPCP and EDC removal through charge repulsion. Twenty three types of PES membranes were prepared using two amounts of different CSMMs and two drying (or evaporation) times. The experiments were designed to obtain the membranes' performances in terms of normalized standard flux (NSF), molecular weight cut-off (MWCO), Surface charge (SC), static contact angle and their removal efficiency towards one EDC (bisphenol A) and three PPCPs (carbamazepine, ibuprofen, and sulfamethazine). The correlation between NSF versus SC, MWCO, pore density, and porosity was discussed. The filtration experiments showed an initial partial removal of the target compounds, but no removal in the later stages of operation, which indicated that charge repulsion was not the controlling removal mechanism. This is consistent with small changes in membrane Surface charge achieved by addition of these additives. Given the decrease in the percent removal with time, removal by size exclusion was also not significant as expected because the membranes had a MWCO greater than 10 kilo-Dalton while the target compounds had molecular weights in the 200 to 300 Dalton range. Based on the decreasing level of removal with time, it appeared that adsorption was the main removal mechanism.
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Performance of Surface‐modified poly(etherimide) hollow‐fiber membranes in a membrane gasLiquid contacting process with response Surface methodology
Journal of Applied Polymer Science, 2012Co-Authors: Ghazali Bakeri, Takeshi Matsuura, Dipak Rana, A.f. Ismail, Azadeh GhaeeAbstract:A Surface-Modifying Macromolecule (SMM) was used to enhance the Surface hydrophobicity of poly(ether imide) (PEI) hollow-fiber membranes. The membranes were used for a membrane contactor to absorb CO2 with water. The effects of three hollow-fiber fabrication parameters, that is, the PEI concentration in the casting dope, the SMM concentration in the casting dope, and the air gap, on the liquid entry pressure of water (LEPw) and the absorption rate (AR) of CO2 were investigated with response Surface methodology. The model developed for LEPw satisfied the criterion for regression but had a low goodness of fit. The model predicted that LEPw would increase with PEI (weight percentage) but decrease with air gap. Furthermore, it showed a minimum value with a change in SMM (weight percentage). The model developed for the AR of CO2 had meaningful statistical parameters and was accurate; this indicated that interactions existed between the fabrication parameters on the AR of CO2. The performance of one of the fabricated membranes was compared with in-house and commercially made hydrophobic membranes in terms of the AR of CO2 with distilled water as an absorbent on the lumen side and pure CO2 on the shell side. The comparison showed a superior CO2 flux in the Surface-modified membrane; for example, at a liquid velocity of 0.4 m/s, the Surface-modified membrane exhibited a 416% higher AR than the commercial membrane contactor (Celgard MiniModule 0.75X5) made of polypropylene. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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a novel Surface modified polyvinylidene fluoride hollow fiber membrane contactor for co2 absorption
Journal of Membrane Science, 2012Co-Authors: Masoud Rahbarisisakht, Ahmad Fauzi Ismail, Dipak Rana, Takeshi MatsuuraAbstract:A novel Surface modified polyvinylidene fluoride (PVDF) hollow fiber membrane was fabricated via a dry–wet phased inversion process. A Surface Modifying Macromolecule (SMM) was used as an additive in the spinning dope. During phase inversion SMM migrates to the membrane Surface and functions as both a pore former and Surface modifier. The Surface modified PVDF membrane showed large pore size, higher effective Surface porosity, contact angle and porosity but lower critical water entry pressure compared to the PVDF hollow fiber membrane without SMM. The performance of the Surface modified membrane in contactor application for CO2 absorption via distilled water as absorbent was studied. The results show that the Surface modified PVDF membrane has higher performance compared to control PVDF membranes. With the membrane prepared from SMM in the spinning dope a maximum CO2 flux of 7.7×10−4 mol/m2 s was achieved at 300 ml/min of absorbent flow rate, which was almost 93% more than the other membrane. In a long-term stability study, CO2 flux was decreased only about 7.7% by using Surface modified PVDF membrane during 150 h operation.
Mohamed Khayet - One of the best experts on this subject based on the ideXlab platform.
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application of a porous composite hydrophobic hydrophilic membrane in desalination by air gap and liquid gap membrane distillation a comparative study
Separation and Purification Technology, 2014Co-Authors: M. Essalhi, Mohamed KhayetAbstract:Abstract A first attempt was carried out comparing the two membrane distillation (MD) configurations, liquid gap (LGMD) and air gap (AGMD), using a porous composite hydrophobic/hydrophilic membrane, the same system and the same MD operating parameters. The Surface modified membrane was prepared by the phase inversion technique in a single casting step using a fluorinated Surface Modifying Macromolecule (SMM). Different membrane characterization techniques were applied. MD experiments were performed at different feed temperatures and sodium chloride aqueous solutions. The permeate fluxes were found to be slightly higher (2.2–6.5%) for LGMD compared to that of AGMD although the resistance to mass transfer in LGMD is higher due to the presence of the liquid permeate layer between the membrane and the cooling solid Surface. This observed enhancement is attributed partly to the small established distance between the liquid/vapor interfaces at both side of the hydrophobic thin top-layer of the membrane in LGMD configuration, and the higher thermal conductivity of water, which is an order of magnitude higher than that of air, resulting in higher heat transfer coefficient of the permeate in LGMD. The salt rejection factors were found to be almost similar for both MD variants and higher than 99.61%. Compared to AGMD, the thermal efficiency is higher for LGMD, whereas the specific internal heat loss is lower. A linear increase of the thermal efficiency with the feed inlet temperature was observed for both MD configurations. The global heat transfer coefficient and the heat transfer of the permeate membrane side were also found to be greater for LGMD. The temperature polarization effect was found to be slightly higher for AGMD, whereas the concentration polarization effect was slightly higher for LGMD due to its higher permeate flux. In general, the LGMD proved to be more attractive than AGMD for desalination when using bi-layered hydrophobic/hydrophilic membranes.
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Application of a porous composite hydrophobic/hydrophilic membrane in desalination by air gap and liquid gap membrane distillation: A comparative study
Separation and Purification Technology, 2014Co-Authors: M. Essalhi, Mohamed KhayetAbstract:Abstract A first attempt was carried out comparing the two membrane distillation (MD) configurations, liquid gap (LGMD) and air gap (AGMD), using a porous composite hydrophobic/hydrophilic membrane, the same system and the same MD operating parameters. The Surface modified membrane was prepared by the phase inversion technique in a single casting step using a fluorinated Surface Modifying Macromolecule (SMM). Different membrane characterization techniques were applied. MD experiments were performed at different feed temperatures and sodium chloride aqueous solutions. The permeate fluxes were found to be slightly higher (2.2–6.5%) for LGMD compared to that of AGMD although the resistance to mass transfer in LGMD is higher due to the presence of the liquid permeate layer between the membrane and the cooling solid Surface. This observed enhancement is attributed partly to the small established distance between the liquid/vapor interfaces at both side of the hydrophobic thin top-layer of the membrane in LGMD configuration, and the higher thermal conductivity of water, which is an order of magnitude higher than that of air, resulting in higher heat transfer coefficient of the permeate in LGMD. The salt rejection factors were found to be almost similar for both MD variants and higher than 99.61%. Compared to AGMD, the thermal efficiency is higher for LGMD, whereas the specific internal heat loss is lower. A linear increase of the thermal efficiency with the feed inlet temperature was observed for both MD configurations. The global heat transfer coefficient and the heat transfer of the permeate membrane side were also found to be greater for LGMD. The temperature polarization effect was found to be slightly higher for AGMD, whereas the concentration polarization effect was slightly higher for LGMD due to its higher permeate flux. In general, the LGMD proved to be more attractive than AGMD for desalination when using bi-layered hydrophobic/hydrophilic membranes.
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Surface segregation of fluorinated Modifying Macromolecule for hydrophobic hydrophilic membrane preparation and application in air gap and direct contact membrane distillation
Journal of Membrane Science, 2012Co-Authors: M. Essalhi, Mohamed KhayetAbstract:A fluorinated Surface Modifying Macromolecule (SMM) was synthesized and blended into the casting solution of polyetherimide used as host polymer. A composite porous hydrophobic/hydrophilic membrane was prepared by the phase inversion technique in a single casting step. The membrane was characterized by different techniques. During membrane formation, SMM migrates to the top membrane Surface increasing its hydrophobicity and decreasing its pore size, nodule size and roughness parameters. The thickness of the porous hydrophobic top layer was found to be around 4 mu m. The membrane was used for desalination by air gap membrane distillation and direct contact membrane distillation. The experiments were performed for different sodium chloride aqueous solutions and various operating conditions. The water production rate was found to be high for direct contact membrane distillation because of the low resistance to mass transport achieved by the diminution of the water vapour transport path length through the hydrophobic thin top-layer of the membrane.
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Surface segregation of fluorinated Modifying Macromolecule for hydrophobic/hydrophilic membrane preparation and application in air gap and direct contact membrane distillation
Journal of Membrane Science, 2012Co-Authors: M. Essalhi, Mohamed KhayetAbstract:A fluorinated Surface Modifying Macromolecule (SMM) was synthesized and blended into the casting solution of polyetherimide used as host polymer. A composite porous hydrophobic/hydrophilic membrane was prepared by the phase inversion technique in a single casting step. The membrane was characterized by different techniques. During membrane formation, SMM migrates to the top membrane Surface increasing its hydrophobicity and decreasing its pore size, nodule size and roughness parameters. The thickness of the porous hydrophobic top layer was found to be around 4 mu m. The membrane was used for desalination by air gap membrane distillation and direct contact membrane distillation. The experiments were performed for different sodium chloride aqueous solutions and various operating conditions. The water production rate was found to be high for direct contact membrane distillation because of the low resistance to mass transport achieved by the diminution of the water vapour transport path length through the hydrophobic thin top-layer of the membrane.
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Characterization of Surface‐modified hollow fiber polyethersulfone membranes prepared at different air gaps
Journal of Applied Polymer Science, 2007Co-Authors: Kailash Chandra Khulbe, Takeshi Matsuura, Roberto M Narbaitz, C. Feng, D. C. Mosqueada-jimenaez, Mehrdad Rafat, D. Kingston, Mohamed KhayetAbstract:Hollow fibers were spun from a solution of Surface-Modifying Macromolecule blended polyethersulfone in dimethyl acetamide by using dry-wet spinning method at different air gaps and at room temperature. The air gap was varied from 10 to 90 cm. The ultrafiltration performance of hollow fibers was studied by using aqueous solutions of polyethylene glycols and polyethylene oxides of different molecular weights. Significant difference in Surface morphology between the inner and outer Surface of the hollow fibers was observed by atomic force microscopy (AFM). Similar results were obtained by contact angle measurement and XPS. Mean pore sizes of the inner Surface and outer Surface were calculated from AFM images and compared with the pore sizes obtained from mass transport data. Pore size distribution curves were drawn from both data, i.e., from AFM images and mass-transport data, both methods gave similar results.Roughness parameters of the inner and outer Surfaces and the sizes of nodular aggregates on both Surfaces were measured. An attempt was made to correlate the above parameters with the performance of the membranes. Unexpected values of contact angles of both inner Surface and outer Surface were obtained. It was observed that the studied membranes could be put into two groups: (i) the membranesfabricated between 10 and 50 cm air gap and (ii) fabricated at higher than 50 cm air gap. A plausible mechanism for the unexpected results was discussed.
Mostafa Ghasemi - One of the best experts on this subject based on the ideXlab platform.
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SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell
Journal of Chemical Technology & Biotechnology, 2015Co-Authors: Alireza Mayahi, Ahmad Fauzi Ismail, Juhana Jaafar, Masoud Rahbari-sisakht, Hamid Ilbeygi, Wan Ramli Wan Daud, Daryoush Emadzadeh, Ezzatollah Shamsaei, Darren J. Martin, Mostafa GhasemiAbstract:Sulfonated poly (ether ether ketone) (SPEEK) membranes and their modifications are viewed as arguably the most promising in microbial fuel cell (MFC) applications due to their non-fluorinated base, superior chemical stability, and lower costs compared with Nafion membranes. In this work, SPEEK membranes with different degrees of sulfonation (DSs) (60% to 76%) and blended with charged Surface Modifying Macromolecule (cSMM) were used as electrolytes in an MFC for simultaneous electricity generation and wastewater treatment. RESULTS: Performance evaluation of newly fabricated membranes was carried out and was compared with that of Nafion 117. The MFC with SPEEK76/cSMM generated about 16.5% higher maximum power density (172.1 mW m-2) than that with Nafion 117 (143.7 mW m-2). In addition, the SPEEK76/cSMM exhibited the highest coulombic efficiency (CE) of 17.6%, which was 21.6% higher than that of Nafion 117 (13.8%). Chemical oxygen demand (COD) removal of all characterized membranes was above 80% in our particular MFC. CONCLUSION: MFC is a suitable method for simultaneous wastewater treatment and electricity generation. SPEEK76/cSMM is a promising membrane to be applied in MFC. © 2014 Society of Chemical Industry.
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Effect of operating temperature on the behavior of promising SPEEK/cSMM electrolyte membrane for DMFCs
Separation and Purification Technology, 2013Co-Authors: Alireza Mayahi, Ahmad Fauzi Ismail, M.n.a. Mohd Norddin, Hamid Ilbeygi, Mostafa Ghasemi, Mohd Hafiz Dzarfan Othman, Takeshi MatsuuraAbstract:Abstract The behavior of sulfonated poly (ether ether ketone) (SPEEK) with different degrees of sulfonation (DS) (60–76%) blended with charged Surface Modifying Macromolecule (cSMM) at different operating temperatures as an electrolyte membrane for direct methanol fuel cell (DMFC) application has been studied. A good DMFC electrolyte membrane should possess high proton conductivity and low methanol permeability. In this work, the fabricated SPEEK/cSMM membranes were compared with pure SPEEK and commercial Nafion 112 membranes in terms of water uptake, proton conductivity, and methanol permeability at temperature range of room to 80 °C. The water uptake of SPEEK/cSMM membranes increased with the temperature and it was higher than that of SPEEK and Nafion 112 membranes; however newly fabricated membranes with 68% and 76% DS were dissolved at high temperatures although showed the same trend at lower temperatures. In agreement with the result of water uptake, proton conductivity of SPEEK/cSMM membranes also increased with temperature and was higher as compared to the corresponding SPEEK membranes; however it was still lower than that of Nafion 112. The methanol permeability values of the SPEEK/cSMM membranes were lower at different temperatures as compared to corresponding SPEEK and Nafion 112 at the same condition. Owing to considerable proton conductivity and lower methanol permeability values, SPEEK60/cSMM exhibited the highest overall performance than other tested membranes at 60 °C. These results indicated that SPEEK60/cSMM membrane is promising to be used as a polymer electrolyte membrane in direct methanol fuel cell.