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Multidisciplinary, innovative and high values development of high performance, cost-effective and environmentally acceptable separation systems is highly desired to tackle the sustainability challenges that facing current desalination technology. Owing to their versatility and immense potentials to evolve scientific and technical innovations, nanotechnology is probably one of the most prominent strategies that has gained growing scientific and public recognition to provide solutions that can extend the limits of sustainability in membrane desalination technology. This short review provides a brief insight into the roles and prospective of nanotechnology, particularly the nano-enabled membrane technology, to serve as a key element to render feasible solutions for sustainable development in membrane desalination technology. The contribution also highlights the strategies of transforming risk and challenges of this cutting edge technology into competitive advantage in order to timely and efficiently drive values in enhancing the desalination performance, profits and sustainability. The applications of nanomaterials and nanocomposite in membrane desalination are anticipated to foster untapped initiatives and innovation in fundamental science, engineering and technology to spearhead the new wave of leading edge sustainable membrane desalination technology. [ABSTRACT FROM AUTHOR]

In this study, laundry wastewater filtration was studied using hydrophilic polyvinylpyrollidone (PVP) modified polyethersulfone (PES) ultrafiltration membranes. The performances of PES/PVP membranes were assessed using commercial PES membrane with 10 kDa in ultrafiltration. Operating parameters The influence of transmembrane pressure (TMP) and stirring speed on laundry wastewater flux was investigated. A higher permeate flux of 55.2 L/m 2 h was obtained for modified PES membrane with high concentration of PVP at TMP of 500 kPa and 750 rpm of stirring speed. The separation efficiencies of membranes were also studied with respect to chemical oxygen demand (COD), total dissolved solids (TDS), turbidity and conductivity. Results showed that PES membrane with 10% of PVP had higher permeate flux, flux recovery and less fouling when compared with other membranes. Higher COD and TDS rejection of 88% and 82% were also observed for modified membranes due to the improved surface property of membranes. This indicated that modified PES membranes are suitable for the treatment of surfactant, detergent and oil from laundry wastewater. [ABSTRACT FROM AUTHOR]

Polyacrylonitrile (PAN)-based hollow fiber membranes were fabricated via a dry/wet phase inversion process with the addition of poly(vinyl alcohol) (PVA). The hollow fiber ultrafiltration (UF) membranes were prepared by varying the weight ratio of PVA:PAN in dope solution followed by investigation on the effect of PVA composition on the UF membrane properties and performance. Protein filtration experiments using bovine serum albumin (BSA) were conducted to study the permeation and anti-fouling properties of the PAN/PVA blend membranes as a function of time. It is found that PAN/PVA blend membranes showed better hydrophilicity than that of pristine PAN membrane. It is also found that the best ratio of PAN:PVA in dope solution is 85:15 in which the membrane exhibited good morphology and was able to achieve excellent pure water flux of 251.37?L/m2?h?bar and BSA rejection of 97%. Nevertheless, it must be pointed out that the presence of excessive PVA composition in dope solution could negatively affect membrane morphology and its performance. For anti-fouling performance, blend membrane prepared from PAN:PVA ratio of 95:5 demonstrated the best fouling resistant among all the membranes studied. Results showed that further increase in the composition of PVA in the PAN membrane did not necessarily enhance anti-fouling properties of UF membrane. [ABSTRACT FROM PUBLISHER]

Asymmetric PEI hollow fiber mixed matrix membranes (MMMs) with improved structure and wetting resistance were fabricated via wet phase inversion method. The effects of incorporating hydrophobic MMT into polymer matrix in different loadings on the membrane properties were investigated. The membranes were characterized in terms of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), gas permeation test, hydrophobicity, wetting resistance and mechanical stability. All membranes possessed finger-like structures differing in skin layer thickness which increased with clay loading. The results revealed that the MMMs have significantly smaller pore size, higher porosity, hydrophobicity, LEPw and mechanical stability than plain PEI membrane. The membranes were further characterized by CO 2 absorption test via contactor system using distilled water as absorbent and pure CO 2 as solute gas. The results showed that the CO 2 absorption performance increased with addition of MMT nano-clay. The membrane containing 1 wt% MMT recorded the highest absorption flux of 2.35 × 10 −3 mol m −2 s −1 at the liquid velocity of 3 m s −1 , almost 135% higher than the flux of plain membrane at the same velocity. Comparatively, the flux of MMM was superior to several in-house made and commercial membranes. [ABSTRACT FROM AUTHOR]

Polyvinylideneflouride (PVDF) hollow fiber mixed matrix membranes (MMMs) were fabricated through wet phase inversion method using general MMT and Cloisite 15A as inorganic fillers. The effect of clay filler loadings (1, 3 and 5 wt% of polymer), their particle size and hydrophobicity on the membrane morphology, structure and performance in gas–liquid contacting process were investigated. The fabricated MMMs were characterized by scanning electron microscopic (SEM), gas permeation test, hydrophobicity, wetting resistance and CO 2 absorption test. As expected, MMMs showed asymmetrical structure, differing in finger-like portion, porosity and pore size. The fabricated MMMs with higher finger-like area and surface porosity showed higher permeance than plain membrane. Furthermore, the wetting resistance in terms of surface hydrophobicity and liquid entry pressure of water increased with loading. From the point of view of physical CO 2 absorption, the membranes incorporated with small particle size filler (general MMT-filled PVDF membranes) exhibited higher absorption fluxes than those embedded with large particle size fillers. The highest absorption flux for membrane containing 1 wt% general MMT is 1.0 × 10 −3 mol m −2 s −1 at the flow rate of 3.1 m s −1 . That flux was approximately 54% and 82% higher than the flux of MMMs with embedded Cloisite 15A of the same loading and plain PVDF membrane, respectively. The obtained flux of synthesized membrane was superior compared to several in-house made and commercial membranes. [ABSTRACT FROM AUTHOR]

Abstract: A novel composite membrane was prepared using chitosan (CH) as the active layer supported on a Poly(1,4-phenylene ether ether sulfone) (PPEES) membrane. The chitosan layer was ionically cross linked with sodium tripolyphosphate (TPP). The composite nature of PPEES/CH membranes was confirmed by Scanning Electron Microscopy (SEM). Infrared (IR) spectroscopy results and SEM–EDX analysis confirmed the crosslinking of chitosan surface with TPP. The membranes exhibited higher crosslinking density in acidic media than in basic media. The changes in the hydrophobic nature of PPEES membrane surface due to deposition of chitosan active layer followed by crosslinking were studied by their contact angle measurement, water flux and water uptake studies. The membranes showed rejection up to 55% and 21% towards MgSO4 and NaCl respectively at pH=5 and a flux recovery ratio of 73%. [Copyright &y& Elsevier]

Highlights: [•] Blending SMM resulted in higher hydrophobicity and gas permeability. [•] The modified membrane showed higher wetting resistance at 24cm air gap. [•] The membrane showed less mass transfer resistance by removing inner skin. [•] Increasing air gap and SMM concentration resulted in higher CO2 flux. [•] A long-term stable operation was achieved by developing PVDF membranes. [Copyright &y& Elsevier]

Highlights: [•] Zeolite 4A loaded Pebax-1657 mixed matrix membranes were synthesized. [•] Performance of membranes was studied with pure CO2, CH4, O2 and N2 gases. [•] Pebax/4A membranes showed better gas permeation properties to those of Pebax-1657. [•] Increasing the zeolite loading enhanced the selectivity CO2/CH4, CO2/N2 and O2/N2. [ABSTRACT FROM AUTHOR]

Highlights: [•] Asymmetric mixed matrix membranes were fabricated. [•] Organoclay particles known as Cloisite® 15A were incorporated in PSF matrix. [•] Permeability of CO2, O2, N2, and CH4 increased with increasing filler loading. [•] O2/N2 and CO2/CH4 selectivity was maintained up to 1wt.% C15A loading. [ABSTRACT FROM AUTHOR]

Highlights: [•] Different amount of SMM were used to improve the surface hydrophobicity of PVDF HFM. [•] Average pore size and contact angle increased by increasing SMM concentration. [•] The fabricated PVDF HFMs were used in contactor application for CO2 absorption. [•] The CO2 flux of the hollow fiber increased by increasing SMM concentration. [•] The membrane mass transfer resistance decreased by enhancement of SMM concentration. [Copyright &y& Elsevier]

Highlights: [•] Beta-cyclodextrin was used to functionalize raw MWCNTs. [•] The TEM results showed beta-cyclodextrin can attach to the outer surface of the MWCNTs. [•] After functionalization, shortened and less agglomerated MWCNTs were achieved. [•] TGA revealed that the functionalized MWCNTs are thermally less stable than raw MWCNTs. [•] Functionalized MWCNTs increased selectivity of the mixed matrix membranes considerably. [Copyright &y& Elsevier]

Highlights: [•] The effect of different fiber packing density was studied in membrane contactor. [•] Increasing packing density produces decreasing trend of CO2 absorption flux. [•] Overall mass transfer resistance reduced with increasing packing density. [Copyright &y& Elsevier]

Highlights: [•] A critical review on the conventional gas permeation testing (GPT). [•] Determining shortcomings of the conventional GPT. [•] Applying the conventional GPT leads to erroneous predictions. [Copyright &y& Elsevier]

Abstract: Carbon dioxide (CO2) stripping from water was conducted through the porous asymmetric polysulfone (PSf) hollow fiber membrane contactor. The effect of the liquid and gas flow rates on the stripping performance, the liquid phase CO2 concentration and the CO2 stripping efficiency of the membrane module and the effect of liquid phase temperature on CO2 stripping flux were studied. The experimental results showed that the stripping gas velocity had a minor effect on the CO2 desorption flux while the increase in the liquid velocity could enhance CO2 desorption flux in the gas stripping membrane contactor. By increasing liquid flow rate to 200ml/min, the maximum CO2 stripping efficiency of almost 66% was achieved. Enhancement of liquid flow rate from 50 to 200ml/min increased the CO2 flux around 482%. It was found that the CO2 stripping flux was significantly affected by the liquid phase temperature. By increasing liquid temperature from 80 to 90°C, the CO2 stripping flux increased from 1.3×10−4 to 4.9×10−4 molm−2 s−1 at liquid velocity of 200mlmin−1. Hence, the higher stripping efficiency can be achieved by applying the higher liquid flow rate in the membrane contactor module. As well, the liquid phase temperature is a key parameter that needs to be controlled. [Copyright &y& Elsevier]

Abstract: A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13–16wt.%) 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 14wt.% 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. [Copyright &y& Elsevier]

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. [Copyright &y& Elsevier]

Abstract: Three different types of commercial membranes, i.e. UF PVDF100 (MWCO 100kDa), UF PES30 (MWCO 30kDa) and NF270 were used to treat car wash effluent and were evaluated with respect to permeate flux, rejection of conductivity, total dissolved solid (TDS), chemical oxygen demand (COD) and turbidity. Results revealed that NF270 exhibited greater flux stability and higher flux recovery during treatment process compared to PVDF100 and PES30 membranes, indicating its higher resistance against fouling. With respect to turbidity removal, it is found that minimum rejection of 92% could be achieved irrespective of membrane properties and effluent characteristics. The performance of membrane in COD reduction was however dependent on its properties in which NF270 showed the highest retention rate (70.9–91.5%) followed by PES30 (54.9–83.9%) and PVDF100 (56.1–82.4%). Compared to NF270, both UF membranes were found ineffective in reducing conductivity and TDS of effluent. NF270 displayed at least 60% separation rate in conductivity and TDS removal compared to 13.6–35.4% reported in PVDF100 and PES30 membranes. The features demonstrated by NF270 in separating the pollutants from the car wash effluent coupled with stable water production make the membrane a good candidate to be employed and offer an environmentally sustainable option to car wash industry. [Copyright &y& Elsevier]

Abstract: The influence of air bubble flow rate (ABFR), hydraulic retention time (HRT), mixed liquor suspended solid (MLSS) concentration, and pH on the performances of modified polyvinylidene fluoride (PVDF) was investigated in submerged membrane ultrafiltration (SMUF).The refinery wastewater process was conducted using an experimental set-up consisted of an SMUF reservoir, a circulation pump, and an aerator. For SMUF, operated at vacuum pressure, deposition and accumulation of suspended solids on membrane surface were prohibited with continuous aeration. The process performance was measured in terms of the membrane water flux and chemical oxygen demand (COD) removal efficiency. The air bubbles flow rate was controlled at 1.2–3.0mL/min while HRT was manipulated in the range of 120–300min. MLSS and pH solution were controlled at 4.5g/L and 6.5, respectively. Results from response surface methodology (RSM) have demonstrated the improvement in water flux and COD removal, achieving 145.7L/m2 h and 90.8%, respectively. By using pH at 6.50, the optimized conditions achieved for refinery wastewater treatment were 2.25mL/min, 276.93min, 4.50g/L for ABFR, HRT and MLSS concentration, respectively. [Copyright &y& Elsevier]

Abstract: Wetting resistance and gas permeability are the main factors for membrane contactor applications, which can be optimized according to the membrane morphology. In present study, three different types of the membrane morphology were obtained via a dry–wet spinning technique. By measuring cloud point data and viscosity, the polymer dope composition was adjusted to produce the different morphologies. The membranes with large finger-like, small finger-like and almost sponge-like morphology were obtained. The plain PVDF membrane with large finger-likes morphology presented the higher N2 permeance, lower wetting pressure and larger mean pore size (0.08μm). By addition of phosphoric acid into the spinning dope, the prepared sponge-like morphology resulted in the high surface porosity with small pore sizes, which demonstrated good permeability and wetting pressure. It was found that the mean pore size measured by gas permeation method was approximately three times larger than those from FESEM examination. CO2 stripping from water was conducted through the gas–liquid membrane contactors. The membranes with smaller pore sizes and higher wetting pressure presented higher stripping performance. In conclusion, a structurally developed PVDF hollow fiber membrane for gas–liquid contactor applications can be achieved by controlling the membrane morphology. [Copyright &y& Elsevier]

Abstract: A novel antibacterial and anti-adhesion membrane was obtained by blending PES with 2,4,6-triaminopyrimidine (TAP) as compatibilizer and AgNO3 as an antibacterial agent. The modified membrane surfaces analyzed by XPS revealed high content of silver (Ag) compared to PES/Ag without compatibilizer. This result was supported by AFM micrographs where PES/TAP/Ag exhibited smoother surface with RMS(nm) 17.49 and Ra(nm) 11.74. From the biofouling point of view, the smoother the surface, the lesser contact area provided thus reducing bacterial adhesion. In addition, PES/TAP/Ag membrane prepared via simple phase inversion technique showed evidence of an anti-adhesion property when tested on Escherichia coli suspension of 1×104 cells/mL at 37°C. The smooth, anti-adhered surface of PES/TAP/Ag however exhibits better tensile strength up to 52% compared to pristine PES membrane, making it an antibacterial membrane with reduced biofouling potentials in water and waste water treatment. [Copyright &y& Elsevier]

Abstract: Microscopic observation was made to investigate the surface structure of porous polyvinylidene fluoride hollow fiber membranes. Field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and the Guerout–Elford–Ferry equation applied for pure water permeation rate were used to determine the average pore sizes. As well, surface roughness parameters and nodule sizes were determined by AFM. The observed unmodified and modified PVDF hollow fiber membranes were prepared by dry-jet wet spinning method from spinning dope mixtures containing 19wt.% PVDF, 0.98wt.% lithium chloride (LiCl.H2O) and 0, 1.95, and 3.85wt.% titanium dioxide (TiO2). Significant difference of spun fibers surface morphology was observed between inner and outer surface by AFM and FESEM. Higher TiO2 concentration formed rougher surfaces, increased average nodule sizes, and decreased the pore size, resulting in lower permeation flux. Pore size obtained from AFM was intermediate between FESEM and the method based on the Guerout–Elford–Ferry equation. [Copyright &y& Elsevier]

Abstract: Mixed matrix membrane (MMM) is a new class of membrane materials that offers the significant potential in advancing the current membrane-based separation technology. As an attractive material that demonstrates outstanding separation properties, MMM has been the subject of worldwide academic studies conducted by many researchers especially those related to membrane technology. The past decades have witnessed substantial progress and exciting breakthroughs in both the fundamental and application aspect of MMM in various forms of separation, particularly in gas separation. These emerging materials for separation have been traditionally accomplished by incorporating conventional inorganic fillers such as zeolite, carbon molecular sieve and silica nanoparticles in a polymer matrix. The recent advances have shifted towards the introduction of new and novel materials namely carbon nanotubes, metal organic framework and clay layered silicate as potential fillers in the polymer matrix. The successful implementation of MMM depends greatly on the polymer matrix selection, the inorganic filler as well as the interaction between the two phases. The selection of suitable types of inorganic filler, the surface modification, and the performance of the resulted MMM membranes were discussed and represented the major contribution in this review. The recent efforts to tackle the underlying problems and the effects of various kinds of modification that would eventually heighten the performance of membrane applications in gas separations were discussed. Better understanding on the improvement and optimization of MMM process was provided by considering the possible solutions to overcome the problems encountered during MMM preparation. This hybrid system holds significant potential and great promise for further investigations, development and applications. The future direction and perspective in MMM research for gas separation was also briefly outlined to further advance the materials for MMM in gas separation. [Copyright &y& Elsevier]

Abstract: This study investigated the gas separation and transport properties of asymmetric mixed matrix membranes (MMM) fabricated from polyetherimide (PEI); Ultem 1000 incorporated with raw and modified halloysite nanotubes (HNT) as filler. The modified HNTs; S-HNTs were prepared by treating HNTs with N-β-(aminoethyl)-γ-aminopropyltrimethoxy silane (AEAPTMS). FESEM, XRD, FTIR, TGA, DSC and pure gas permeation testing were used to characterise the S-HNTs and the fabricated MMMs. In the first part of the experiments, the effect of dope preparation factors such as: ultrasonic sonication period, filler wetting period and priming period were investigated. In the second part, the influence of silane concentration on the fabricated MMMs was studied. Results showed that, increasing the silane concentration, led to higher tendency in HNT agglomeration which resulted in poor separation properties but permeability enhancement. In the last part, the effect of S-HNTs loading was experienced. Our observations showed that the dispersion of nanoparticles decreased with an increase in the S-HNTs loading. Accordingly, 0.5% loading of silylated-HNT yielded the optimum MMMs in terms of permeability (27% increase) and selectivity (8% increase). [Copyright &y& Elsevier]

Abstract: Mixed matrix membranes (MMM) comprised of multi-walled carbon nanotubes (MWCNTs) inside polyethersulfone (PES) matrix were fabricated and characterized for gas separation performance. The MWCNTs were purified with acid mixtures (HNO3/H2SO4; v/v=1:3) to remove carbonaceous impurities followed by surface functionalization with 3-aminopropyltriethoxylsilane (APTES) to allow well dispersion of the tubes in organic solvent such as N-methlypyrrolidone (NMP) during the preparation of PES/MWCNTs suspension. Effects of purification, functionalization and MWCNTs loading on the gas permeation properties of the MMM were investigated by varying the MWCNTs loading in the PES matrix from 0.5–3.0wt.%. The fabricated MWCNTs/PES MMM were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA) and pure gas permeation test. Gas permeation measurement showed that MMMs embedded with different kinds of applied CNTs exhibited different separation performances. For example, gas permeation measurement showed that MMM embedded with 1.0wt.% purified and functionalized MWCNTs possessed better performances in terms of permeability and selectivity in comparison to raw MWCNTs. The highest gas selectivity was achieved at 0.5wt.% MWCNTs loadings ( =250.13; =10.65) and decreased as the loadings were increased from 1.0 to 3.0wt.%. The reduction in performance possibly due to the presence of interface voids which became prominent at higher MWCNTs loading. The high selectivity of fabricated MMM suggested that the present works have a great potential to be utilized practically in gas separation technology. [Copyright &y& Elsevier]

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 60ml/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. [Copyright &y& Elsevier]

Abstract: The present research investigated the feasibility of utilizing dual-layer flat sheet membranes for gas separation purpose. Polyetherimide (PEI) was used as top-layer (TL) and blending of polyetherimide and polysulfone (PSF) as sub-layer (SL) polymer matrixes. TL concentration, SL viscosity and SL PEI/PSF composition were chosen as the most important parameters to play with. To study the delamination/adhesion phenomena the PEI/PSF composition of SL was chosen as key-parameter. There was an optimum in the composition which by virtue the delamination phenomenon was suppressed hence guaranteed the TL/SL adhesion. FESEM images were interpreted by solubility analysis and permeation gas testing, and there was a good agreement between the membrane performance and the membrane morphologies. Dual-layer flat sheet membranes at PEI/PSF=17.5/17.5–25/10, showed an enhancement in both permeance and selectivity. In conclusion, combination of incompatible polymer pairs will be a favourable choice to prepare the substrate membrane. Void spaces between the two incompatible polymers will enhance permeation rate of the substrate membrane, and consequently that of the composite membrane. [Copyright &y& Elsevier]

Abstract: Polyethersulfone–silver composite membranes were fabricated via a simple phase inversion method by using silver nitrate (AgNO3) as an antibacterial agent and polyvinylpyrollidone (PVP) of molecular weight 10,000, 40,000 and 360,000Da as dispersant in the dope formulation. The effect of AgNO3 loading on the resulting membrane was studied using field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) techniques. The silver loss during fabrication and pure water filtration was measured using inductive-coupled plasma mass spectrometer (ICP-MS). From XPS and EDX examinations, it was observed that the resulting membrane prepared from 2wt.% AgNO3 and PVP of 360,000Da exhibited high concentration of Ag mainly due to the high Ag-particle entrapment in the membrane structure. The uniform distribution of Ag particles has contributed significantly to 100% inhibition against Escherichia coli (E. coli) growth within 24h incubation. In addition, the results of pure water filtration test showed minimum silver loss during operation, indicating better stability of membrane produced in terms of Ag-entrapment in membrane structure. Based on the findings, it can be concluded that PES–silver composite membrane with PVP of 360,000MW offers huge potential membrane for bacteria removal and disinfection. [Copyright &y& Elsevier]

Abstract: In this study, polysulfone (PSF) hollow fiber membranes with enhanced performance for humic acid removal were prepared from a dope solution containing PSF/DMAc/PVP/TiO2. The main reason for adding titanium oxide during dope solution preparation was to enhance the antifouling properties of membranes prepared. In the spinning process, air gap distance was varied in order to produce different properties of the hollow fiber membranes. Characterizations were conducted to determine membrane properties such as pure water flux, molecular weight cut off (MWCO), humic acid (HA) rejection and resistance to fouling tendency. The results indicated that the pure water flux and MWCO of membranes increased with an increase in air gap distance while HA retention decreased significantly with increasing air gap. Due to this, it is found that the PSF/TiO2 membrane spun at zero air gap was the best amongst the membranes produced and demonstrated >90% HA rejection. Analytical results from FESEM and AFM also provided supporting evidence to the experimental results obtained. Based on the anti-fouling performance investigation, it was found that membranes with the addition of TiO2 were excellent in mitigating fouling particularly in reducing the fouling resistances due to concentration polarization, cake layer formation and absorption. [Copyright &y& Elsevier]

Abstract: The aim of this study was to investigate the effect of pore-forming hydrophilic additives on the porous asymmetric polyvinylideneflouride (PVDF) ultrafiltration (UF) membrane morphology and transport properties for refinery produced wastewater treatment. PVDF ultrafiltration membranes were prepared via a phase inversion method by dispersing lithium chloride monohydrate (LiCl·H2O) and titanium dioxide (TiO2) nanoparticles in the spinning dope. The morphological and performance tests were conducted on PVDF ultrafiltration membranes prepared from a different additive content. The top surface and cross-sectional area of the membranes were observed using a field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) analysis. The surface wettability of porous membranes was determined by the measurement of a contact angle. The mean pore size and surface porosity were calculated based on the permeate flux. The results indicated that the PVDF/LiCl/TiO2 membranes with lower TiO2 nanoparticles loading possessed smaller mean pore size, more apertures inside the membrane with enhanced membrane hydrophilicity. LiCl·H2O has been employed particularly to reduce the thermodynamic miscibility of dope which resulted in increasing the rate of liquid–liquid demixing process. The maximum flux and rejection of refinery wastewater using PVDF ultrafiltration membrane achieved were 82.50L/m2 h and 98.83% respectively at 1.95 wt.% TiO2 concentration. [Copyright &y& Elsevier]

Abstract: This paper focuses on the effect of montmorillonite nano-clay fillers on polyetherimide (PEI) mixed matrix membrane, specifically upon the removal of carbon dioxide. Five different types of montmorillonite (MMT) nano-clays, including unmodified and industrially modified clays, were used as filler to fabricate asymmetric flat sheet mixed matrix membrane (MMM) via a dry/wet phase inversion technique. The five types of clay used were: raw MMT, Cloisite 15A, general MMT, hydrophobic MMT and hydrophilic MMT. The MMTs were characterized by X-ray diffractometry (XRD), thermal gravimetric analysis (TGA), Fourier-transform infrared (FTIR). The fabricated MMMs were characterized by differential scanning calorimetry (DSC), field emission scanning electron microscopic (FESEM) and pure gas permeation testing. The gas permeation results revealed the following order in terms of the permselectivity for CO2/CH4 separation: Cloisite 15A>general MMT>hydrophilic MMT>hydrophobic MMT>raw MMT. The best results were obtained at 0.5wt.% Cloisite 15A loading where the selectivity enhancement was about 28% as compared to that of neat PEI. [Copyright &y& Elsevier]

Abstract: The synergistic combinations of organic polymers for separation applications with inorganic substances such as multi-walled carbon nanotubes (MWNTs), have resulted in a new class of membrane material called mixed matrix membrane (MMM) for the separation of CO2/CH4 gases. Mixed matrix membrane incorporated functionalized MWNTs (f-MWNTs) were fabricated by the solution casting method, in which the f-MWNTs were embedded into the polyimide membrane and the resulting membranes were characterized. The effect of nominal MWNTs content between 0.5 and 1.0wt% on the gas separation properties was investigated. The mixed matrix membranes showed 100% enhancement for the selectivity of CO2/CH4 compared to the corresponding neat polymer membrane. This new class of mixed matrix membrane has the ability to separate gases at the molecular level and has the potential to ultimately reduce the energy consumed in present-day separation operations. This study has shown that addition of CNTs to polymeric membranes has improved separation properties of the membranes to a certain extent. [Copyright &y& Elsevier]

Abstract: Porous polyvinylidene fluoride (PVDF) and polysulfone (PSF) hollow fiber membranes were prepared via a wet spinning method. Glycerol was used as phase-inversion promoter additive in the spinning dopes. Cloud point diagrams of polymer/solvent–glycerol/water were obtained to study precipitation rate of the polymers solution. The membrane structure was compared in terms of morphology, gas permeation, critical water entry pressure, collapsing pressure, overall porosity, contact angle and mass transfer resistance. The cloud point diagrams confirmed a significant increase in the precipitation rate of the spinning dopes with addition of glycerol. The PSF membranes indicated more open cross-section structure with smaller pore sizes. However, the PVDF membranes illustrated an ultra thin outer skin layer with high permeability which resulted in significantly lower mass transfer resistance. Physical CO2 absorption with distilled water was conducted through the gas–liquid membrane contactors. With addition of glycerol, the PVDF membrane demonstrated a structure with significantly higher CO2 flux compared to the commercial asymmetric PVDF membrane. The CO2 flux of 8.20×10−4 mol/m2 s was achieved by using the absorbent flow rate of 310mL/min in the shell side of the membrane module. Therefore, using an improved hollow fiber membrane structure can be a promising alternative for CO2 absorption and separation through membrane contactors. [ABSTRACT FROM AUTHOR]

Abstract: Development of polymeric gas separation membranes is one of the fastest growing branches of membrane technology. However, polymeric materials are somewhat deficient in meeting the requirements of current membrane technology. Mixed matrix membrane (MMM), comprising rigid permeable or impermeable particles, such as zeolites, carbon molecular sieves, silica and carbon nanotubes, dispersed in a continuous polymeric matrix presents an interesting approach for improving the separation properties of polymeric membranes. In this approach, using properties of both the organic and inorganic phase, a membrane with good permeability, selectivity, mechanical strength, and thermal, chemical stability and processibility can be prepared. In this paper the performance studies of MMM for gas separation were critically reviewed. In addition, the materials selection and the preparation techniques of MMM were also discussed. Methodology in improving the interface defects in the MMM and its effect on the separation performance have also been reviewed. The models for predicting the performance of MMM for gas separation have been discussed in details and the future direction of research and development to fully exploit the potential usage of MMM was shown. [ABSTRACT FROM AUTHOR]

Abstract: The effect of chitosan as a functionalization agent on the performance and separation properties of polyimide/multi-walled carbon nanotubes mixed matrix flat sheet membranes were investigated. Polyimide (PI)/raw multi-walled carbon nanotubes (r-MWCNTs) and polyimide (PI)/chitosan-functionalized multi-walled carbon nanotubes (C-f-MWCNTs) mixed matrix membranes were fabricated by phase inversion method. Raw and functionalized multi-walled carbon nanotubes were characterized by transmission electron microscope (TEM). The membrane samples were characterized by SEM, FESEM, DSC and gas permeation tests using He, CO2 and CH4 as test gases. TEM results and gas permeation test using He as test gas showed that r-MWCNTs were generally closed ended and after functionalization, well dispersed open ended chitosan-wrapped MWCNTs were obtained. Gas permeation results showed that addition of 1wt.% (solid base) C-f-MWCNTs into casting dope can increase the CO2 and CH4 permeabilities by 20.48 and 0.71Barrer, respectively. The increase in permeabilities of CO2, CH4 and He in this study can be attributed to the presence of high diffusivity tunnels in the MWCNTs within the polyimide matrix. It is interesting that the CO2/CH4 selectivity was also increased by 51.4% (from 10.9 to 16.5) by addition of C-f-MWCNTs. DSC and FESEM results also revealed a very good dispersion and adhesion of the C-f-MWCNTs in the polyimide matrix. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, polyetherimide (PEI) hollow fiber membranes were used in gas–liquid contacting process. Porous polyetherimide hollow fiber membranes were fabricated via wet phase inversion method. The polymer concentration in dope solution varied from 10 to 15wt%. Water was used as internal and external coagulant. Gas permeation test using helium as test gas, liquid entry pressure of water (LEPw) test and scanning electron microscopy (SEM) were used for membrane characterization. The mean pore size, effective surface porosity and void fraction of membranes decreased as the polymer concentration increased, while LEPw and membrane density increased. CO2 absorption rate of fabricated membranes were measured in a gas–liquid hollow fiber membrane contactor system using distilled water as absorbent and the results showed that CO2 absorption rate of membranes increases as polymer concentration decreases. In addition, CO2 absorption rate of hollow fiber membranes in which polyetherimide concentration was between 10 and 12wt%, was higher than commercial PVDF hollow fiber membranes. [Copyright &y& Elsevier]

Abstract: Silver-filled asymmetric polyethersulfone (PES) membranes were prepared by a simple phase inversion technique. The effects of polyvinylpyrrolidone (PVP) and 2, 4, 6-triaminopyrimidine (TAP) on the surface properties of the silver-filled asymmetric membrane were investigated for antibacterial application. The dispersion of silver nanoparticles (Ag) and silver content on membrane surface were characterized using field emission scanning electron microscope (FESEM) and energy dispersive spectrometer (EDS), respectively. Results showed that smaller silver particles were formed in PES membranes when PVP and TAP were added during dope preparation. Using inductively coupled plasma mass spectrometry (ICP-MS), it is found that silver leaching has been significantly reduced up to 57% and 63% upon the addition of PVP and TAP respectively. The improved silver dispersion on membrane surfaces was able to enhance the antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as evidenced by larger inhibition ring in agar diffusion method. The filtration of E. coli suspension (optical density=0.31 at λ =600nm) carried out on prepared membranes proved that PES–AgNO3 with TAP as dispersant appeared to inhibit almost 100% bacterial growth in rich medium. Hence, overall results showed the potential of PES–AgNO3 with TAP to be used for antibacterial applications especially in water treatment. [ABSTRACT FROM AUTHOR]

Abstract: The cross-linking modification of asymmetric Matrimid membranes with para-phenylenediamine (pPD) has been investigated. The modification was performed by immersing Matrimid membranes in 10% (w/v) pPD/methanol solution at ambient temperature for certain period of time. The effects of immersion time on degree of cross-linking, physicochemical properties and gas transport properties of the membrane have been studied. The cross-linked Matrimid membranes were characterized using gel test, FTIR, TGA, XRD and SEM. The FTIR spectra confirmed that the cross-linking process had taken place, which indicates that imide groups were turned to amide groups during modification process. The degree of cross-linking increased with increasing the immersion time. This study found that, there were small amounts of insoluble materials found from the gel test. The possible reasons were that the proposed cross-linking method using pPD solution occurs only on the surface of the membranes or only low degree of cross-linking takes place. The XRD results revealed that the d-space of the polymeric chains change after the modification due to the methanol swelling and structure-tightening effects induced by cross-linking. The TGA results indicated that the degradation temperature is sufficient for gas separation applications. The gas transport properties of the pure and cross-linked Matrimid membranes were investigated using gas permeation tests. The results showed that the cross-linked Matrimid membranes decrease the O2, N2 and CH4 permeance compared to the unmodified membranes. Interestingly, 10% pPD-120min samples showed an impressive enhancement of selectivity for O2/N2 compared to the unmodified membrane from 6.19 to 10.01 due to the affinity of nitrogen-containing molecules (pPD) towards oxygen. [Copyright &y& Elsevier]

Abstract: Porous polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via a wet phase-inversion method. Ortho-phosphoric acid and lithium chloride monohydrate (LiCl·H2O) were used as phase-inversion promoter additives in the spinning dopes. Ternary phase diagram of the polymer dopes were obtained using cloud point test. The membranes morphology was examined by field emission scanning electron microscopy (FESEM). The prepared membranes were characterized in terms of gas permeation, critical water entry pressure, overall porosity, contact angle and mass transfer resistance. Cloud point data showed that both additives increased precipitation rate of the spinning dopes significantly. From the FESEM examination, the hollow fiber membranes possess an ultra-thin outer skin layer with a thin finger-like layer beneath and a thick sponge-like sub-layer. Results of gas permeation test revealed that phosphoric acid resulted in the membranes with a larger mean pore size than PVDF+LiCl·H2O membrane. In addition, phosphoric acid in the spinning dope provided the hollow fiber membrane structure with significantly enhanced CO2 flux, which is approximately 33% more than the CO2 flux of the PVDF+LiCl·H2O membrane and the commercial PTFE membrane at 320mL/min absorbent flow rate. Therefore, it can be concluded that an improved PVDF membrane structure prepared by phase-inversion process can be a cost-effective alternative for CO2 absorption in gas–liquid membrane contactors. [Copyright &y& Elsevier]

Abstract: Porous polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via a wet phase-inversion process and used in the gas–liquid membrane contactor for physical and chemical CO2 absorption. Effect of different operating parameters such as absorbent temperature, CO2 pressure, absorbent flow rate and long-term operation on the CO2 flux of the membrane were investigated. The characterization results showed that the prepared membrane possess small pore size with high surface porosity and wetting resistance, which are favorable for gas absorption application. Results of CO2 absorption experiments revealed that in case of physical absorption with distilled water, CO2 solubility was the key parameter which significantly affected the membrane CO2 flux. A significant increase in the CO2 flux was observed by increasing CO2 pressure and decreasing the absorbent temperature. However, in case of chemical absorption with NaOH (1M), the reaction rate was dominant, where the CO2 flux was significantly increased by increasing the absorbent temperature. It was also found that when the liquid contacted the outer skin layer of the hollow fiber membrane, the operation was stable at the same gas and liquid pressure without bubble formation in the liquid phase. In addition, the results of long-term study demonstrated that the membrane performance was maintained constant for long-term operation. The initial flux reduction was found to be about 30% within the 23h of physical absorption, and 20% of gradual reduction within 80h of chemical absorption. [Copyright &y& Elsevier]

Abstract: This paper discusses the development of a new theoretical model based on resistance modeling approach to predict mixed matrix membrane (MMM) performance. To develop the proposed model, the element of MMM is considered as a unit cell of body centered cubic (BCC). The network of permeation resistances are developed based on this unit cell. The main parameters considered and discussed are: dispersed filler loading, polymer matrix permeability, dispersed filler permeability, interphase permeability and interphase thickness. The results generated from the proposed model have been verified using seven cases through the published experimental data. Excellent agreement has been obtained in most cases between the model results and the selected published values. Thus, the newly proposed model is capable in predicting the permeability and selectivity for all known MMM morphologies. [Copyright &y& Elsevier]

Abstract: Porous polysulfone (PSf) hollow fiber membranes were fabricated via a phase-inversion method by using low molecular weight additives in the spinning dopes. Polyethylene glycol (PEG200), ethanol, glycerol and acetic acid were used as the additives. An aqueous 95wt.% 1-methyl-2-pyrrolidone (NMP) solution was used as neutral bore fluid to fabricate inner skinless hollow fibers membranes. The precipitation rate of the polymer dopes with the different additives was studied using cloud point measurement. Effect of the additives on the resulting membrane structure, surface porosity, pore size, critical water entry pressure (CEPw) and CO2 absorption performance were investigated. Cloud point diagrams indicated that the precipitation rate of the polymer dopes increased following the trend of glycerol>acetic acid>PEG200>ethanol. Results of gas permeation tests showed that glycerol and PEG200 as additives provided the membranes with the largest and smallest pore size, respectively. Moreover, all the additives resulted in an increase in the surface porosity. The cross-section and inner surface of the membranes were examined via a field emission scanning electronic microscopy (FESEM). Glycerol in the spinning dope provided the membrane structure with a thin finger-like and a thick sponge-like layer, which resulted in a higher CEPw and CO2 absorption rate than the other PSf hollow fiber membranes. [Copyright &y& Elsevier]

Abstract: Hollow fiber membranes are the most applicable form of membranes in laboratory and industrial scale with their large surface to volume ratios. Hollow fiber membranes usually are fabricated by dry–wet solution spinning, where a polymer solution is co-extruded through an annular region with a bore fluid and the nascent hollow fiber passes through an air gap and then enters a liquid coagulation bath. The spinneret dimension, dope and bore fluid flow rates, air gap length, bore fluid and dope compositions and their physical properties, coagulant composition and condition, shear stress within a spinneret, the ratio of dope to bore fluid volumetric flow rate, and the take-up-to-initial velocity ratio (draw ratio) are the primary factors that determine the final hollow fiber morphology and separation properties. All of the aforementioned parameters are not independent and some of them are functions of others. The objective of this paper is to elucidate the interdependence between some of the above parameters. For this purpose, dope and bore fluid axial velocity in the air gap was assumed as a function of the axial distance from the spinneret outlet, z, and radial velocity as a function of the radial distance from the center of the hollow fiber, r, and z. Dimensionless equations of motion and continuity were then simplified and solved simultaneously based on preceding assumptions. It was found from the analysis that the dimensionless axial velocity of dope was a function of the Reynolds number, Capillary number and Stokes number indicating that the axial velocity acceleration in the air gap is determined by viscous, capillary, and gravity force gradients. It was also concluded that the optimum value of the ratio of bore liquid flow rate to dope flow rate is equal to 0.8 of the ratio of the cross-sectional area of the bore fluid to that of the dope at the spinneret outlet. [Copyright &y& Elsevier]

Abstract: This paper extensively discussed the gas permeabilities in MMM using theoretical models and the results were compared with the published experimental data. The models considered are: Maxwell model modified Maxwell model, Lewis–Nielsen model, modified Lewis–Nielsen model and Felske model. The selected models were compared based on published experimental data (168 data point) of MMMs, inorganics including zeolites NaA and NaX and neat polymer permeabilities. The results generated based on standard deviation, σ and absolute average relative error, %AARE for the models studied show a decreasing order: Lewis–Nielsen model>Maxwell model>modified Lewis–Nielsen model> modified Maxwell model>Felske model. This indicates that the most reliable predictive model in predicting gas permeability in MMM is Felske model. [Copyright &y& Elsevier]

Abstract: Sulfonated poly (ether ether ketone) (SPEEK)/Cloisite 15A® nanocomposite membranes were fabricated by incorporating 2,4,6-triaminopyrimidine (TAP) as compatiblizer and characterized for DMFC application. The SPEEK-nanocomposite membranes were prepared via solution intercalation method. The membranes were then characterized based on their thermal and physical properties as a function of Cloisite 15A® and TAP loading. The characteristics of the SPEEK nanocomposite membranes were then compared with the parent SPEEK membrane and the commercially available Nafion 112 membrane. The XRD confirmed that intercalation took place in the SPEEK nanocomposite membranes. The membrane stability, i.e. the liquid uptake in water and in the aqueous methanol solution, as well as the mechanical and thermal stability significantly were improved with the Cloisite 15A® and TAP loadings into the SPEEK polymer matrix. The barrier performance of SPEEK/Cloisite 15A®/TAP was significantly enhanced to compete with the expensive Nafion 112 membrane. Higher proton conductivity of 3.87×10−3 Scm−1, which is higher than that of the parent SPEEK membrane, was also attained. [Copyright &y& Elsevier]

Abstract: Membrane separation processes based on mixed matrix membrane (MMMs) comprising carbon nanotubes (CNTs) embedded in polymer matrix have become one of the emerging technologies and have been actively discussed in contemporary membrane separation literature. The resulting carbon nanotube-mixed matrix membrane (CNT-MMMs) offers a viable route to overcome the limitations demonstrated by the conventional polymeric and inorganic membranes. The exceptional properties of CNTs make them suitable for the development of this new class of hybrid membrane and it is believed to open the road towards the practical applications. In particular, the unusually excellent diffusivity properties of CNT have promised their use in separation processes. This paper reviews the recent and current development of CNT-MMMs for membrane separation. The preparation and modification of this material is also briefly discussed. This is followed by a detailed description of various separation processes, including pervaporation, liquid and gas separation. Furthermore, the future direction and perspective in research for the application of CNT-MMMs has also been briefly outlined. [Copyright &y& Elsevier]

Abstract: Membrane contactors using microporous membranes for acid gas removal have been extensively reviewed and discussed. The microporous membrane acts as a fixed interface between the gas and the liquid phase without dispersing one phase into another that offers a flexible modular and energy efficient device. The gas absorption process can offer a high selectivity and a high driving force for transport even at low concentrations. Using hollow fiber gas–liquid membrane contactors is a promising alternative to conventional gas absorption systems for acid gas capture from gas streams. Important aspects of membrane contactor as an efficient energy devise for acid gas removal including liquid absorbents, membrane characteristics, combination of membrane and absorbent, mass transfer, membrane modules, model development, advantages and disadvantages were critically discussed. In addition, current status and future potential in research and development of gas–liquid membrane contactors for acid gas removal were also briefly discussed. [Copyright &y& Elsevier]

Abstract: Sulfonated poly(ether ether ketone)s (SPEEKs) with different sulfonation degrees (DS) were synthesized and characterized using FTIR and NMR for the preparation of blend nanofiltration (NF) membranes. Blends of polyethersulfone and SPEEK at various SPEEK concentrations and various DS were prepared by a simple dry-jet wet spinning technique. The changes in the morphological and electrical properties of the blend membranes were deduced by employing the combination of irreversible thermodynamic model, Steric-Hindrance Pore (SHP) model and Teorell–Meyer–Sievers (TMS) model and the modeling results have been analyzed and discussed in detail. The results showed that the membrane water flux, pore size and surface charge were dependent on the content and DS of SPEEK used. FESEM–EDX results also provided supporting evidence for the trends observed for the morphological and electrical studies. [Copyright &y& Elsevier]

Abstract: The effect of starch pretreatment temperature and exposure time of raw tapioca starch on cyclodextrins (CDs) production and membrane performance using Thermoanaerobacter cyclodextrin glycosyltransferase (CGTase) were investigated in this study. Response surface methodology (RSM) was used to identify the optimum amount of CDs produced. Results indicated that the optimal exposure time and pretreatment temperature for optimum CDs production were 1 h and 70ºC, respectively. Employment of this critical condition (70ºC) as the starch pretreatment temperature, promoted high CDs production and better preservation on the starch granule structure and increased as such as 93% and 94% of swelling power and leached amylose, respectively. In the case of starch pretreatment temperature that is above the critical value (70ºC), such application would apparently increase the solution viscosity and hydraulic resistance that subsequently decrease the membrane flux, despite increasing the CDs yield, suggesting that temperature is a crucial factor in determining the efficiency of CDs production, in particularly in the continuous system. [Copyright &y& Elsevier]

Abstract: Polyethersulfone (PES) hollow fiber membranes were fabricated using water and polyvinylpyrrolidone as additives and N-methyl pyrrolidinone as solvent. Asymmetric hollow fiber membranes were spun by the dry–wet phase inversion method. A charged surface modifying macromolecule (cSMM) was synthesized and blended into the PES dope. The modification of PES hollow fiber membranes with cSMM was evaluated via contact angle measurement, field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR-ATR) and ionic solute separation performance. Experimental results showed that pure water permeation flux was increased by surface modification with the blended cSMM, which at the same time produced higher ionic solute rejection. From the FESEM, a small increase in the thickness of the hollow fiber outer layer was noticed when the surface was modified by cSMM blending. Nevertheless, there was no significant difference in the overall membrane morphology between the membranes with and without cSMM blending, indicating that the morphology of the base polymer remained practically unchanged. On the other hand, DSC scan and FTIR analysis confirmed the miscibility of cSMM with PES and the presence of cSMM''s functional group, respectively. [Copyright &y& Elsevier]

Abstract: New composite membranes were prepared using sulfonated polyether ether ketone (SPEEK) polymer and inorganic proton conducting fillers developed from tungstosilicic acids (SiWA) loaded on silica–aluminium oxide (SiO2–Al2O3) composite. SiWA was fixed on stable structure (composite oxide) so that it became insoluble in water. The SPEEK polymers were characterized using H NMR and FTIR. XRD analysis was performed on the inorganic proton conducing fillers to reveal the existence of the interaction between SiWA and composite oxide. The membrane structural properties and surface morphologies were characterized with SEM and their performance were examined in terms of proton conductivity, water uptake and methanol permeability. It was found that the presence of inorganic proton conducting fillers led to both high water uptake and proton conductivity (maximum value 6.1×10−2 Scm−1). Low methanol permeability values were recorded for the membranes which appeared as a very promising material to be used in DMFC. [Copyright &y& Elsevier]