Polyethersulfone Blend Research Articles

Investigation of the treatment and antibacterial properties of pollutant-containing water using black phosphorus blended polyethersulfone membranes (BP@PES)

The most important problem of membrane processes is clogging and therefore the reduction of their useful life. In order to eliminate such problems, the production of composite membranes is an option in membrane treatment systems. In this study, the usability of black phosphorus (BP) in membrane treatment systems, and its effect on antibacterial and treatment performance were studied. BP blended PES membranes (BP@PES) produced by loading BP into the polyethersulfone (PES) membranes were used for the treatment of bovine serum albumin (BSA) and Escherichia coli (E. coli). For this purpose, BP was added at three different amounts (0.5 %, 1.0 %, and 2.0 %) into PES membranes. Membranes with different BP amounts produced were named as 0.5%BP@PES, 1.0%BP@PES, and 2.0%BP@PES. After the production of these composite membranes, they were used in the dead-end filtration system and compared with the PES membrane without BP (bare PES). The removal effectiveness of bare PES was found to be 53.40 % in the BSA rejection results, and it was discovered to be 60.90 %, 97.15 %, and 100 % for 0.5%BP@PES, 1.0%BP@PES, and 2.0%BP@PES, respectively. The antioxidant activity of BP was 70.86% at 100 mg/L. Newly prepared BP caused single-strand DNA nuclease abilities at 50, 100, and 200 mg/L. BP showed the effective antimicrobial activity. The most antimicrobial activity was determined as a minimum inhibitory concentration (MIC) value of 8 mg/L against E. hirae and 100 % E. coli viability inhibition activity was achieved at 50 and 100 mg/L after 90 min exposure. BP also inhibited the biofilm formation of P. aeruginosa at 87.19 % and S. aureus at 90.28 % at 50 mg/L. Thus, both the effect of BP on membrane performance and its antibacterial properties were investigated. Pure water fluxes, BSA and E.coli rejection performances, and antibacterial properties of all membranes used in the membrane filtration system were investigated in detail. It is recommended to further investigate BP-containing membranes with different production techniques.

Scaffolds for Cartilage Tissue Engineering from a Blend of Polyethersulfone and Polyurethane Polymers

In recent years, one of the main goals of cartilage tissue engineering has been to find appropriate scaffolds for hyaline cartilage regeneration, which could serve as a matrix for chondrocytes or stem cell cultures. The study presents three types of scaffolds obtained from a blend of polyethersulfone (PES) and polyurethane (PUR) by a combination of wet-phase inversion and salt-leaching methods. The nonwovens made of gelatin and sodium chloride (NaCl) were used as precursors of macropores. Thus, obtained membranes were characterized by a suitable structure. The top layers were perforated, with pores over 20 µm, which allows cells to enter the membrane. The use of a nonwoven made it possible to develop a three-dimensional network of interconnected macropores that is required for cell activity and mobility. Examination of wettability (contact angle, swelling ratio) showed a hydrophilic nature of scaffolds. The mechanical test showed that the scaffolds were suitable for knee joint applications (stress above 10 MPa). Next, the scaffolds underwent a degradation study in simulated body fluid (SBF). Weight loss after four weeks and changes in structure were assessed using scanning electron microscopy (SEM) and MeMoExplorer Software, a program that estimates the size of pores. The porosity measurements after degradation confirmed an increase in pore size, as expected. Hydrolysis was confirmed by Fourier-transform infrared spectroscopy (FT-IR) analysis, where the disappearance of ester bonds at about 1730 cm-1 wavelength is noticeable after degradation. The obtained results showed that the scaffolds meet the requirements for cartilage tissue engineering membranes and should undergo further testing on an animal model.

Thermomechanical and tribological properties of polyimide and polyethersulfone blends reinforced with expanded graphite particles at various elevated temperatures

AbstractExpanded graphite (EG) particles were introduced into the polyimide (PI) and polyethersulfone (PES) blend to enhance the dynamic thermomechanical and tribological performances of this polymer composite at evaluated temperatures ranging from room temperature to 250°C. The influences of EG dosage, evaluated temperature and vertical loads on the high‐temperature tribological behaviors, worn surface morphologies and wear mechanisms of EG/PES/PI composites were analyzed. Experimental results suggest that tensile strength, dynamic storage modulus, glass transition temperature as well as thermal stability of EG/PES/PI composites are superior to those of the PES/PI blend and they are raised as the EG additions increase. Whether at room temperature or at the high temperature of 250°C, the EG/PES/PI composites display the better friction‐reducing and abrasion resistant performances than the PES/PI blend. Among all these composites, the 7.0 wt% EG/PES/PI composite demonstrates the best friction and wear properties (0.23, 5.68 × 10−16 m3/[N·m]) at evaluated temperatures. The noticeable improvement in abrasive property of EG/PES/PI composites at high‐evaluated temperatures stems from extraordinary porous microstructures and outstanding lubrication characteristics of EG particles as well as the formation of uniform self‐lubricating polymer tribofilms. This composite as antifriction and wear‐resistant materials possesses potential applications in high‐temperature engineering tribology, such as rolling bearing retainer, and so forth.

Characteristics and Performances of Blended Polyethersulfone and Carbon‐Based Nanomaterial Membranes: Effect of Nanomaterial Types and Air Exposure

AbstractPolyethersulfone (PES) is a widely used polymeric material for ultrafiltration or nanofiltration membranes. To enhance membrane permeability, rejection, and antifouling performance, the effect of four different types of carbon‐based nanomaterials and air exposures during PES/carbon‐based nanomaterial membrane fabrication was evaluated. The carbon‐based nanomaterials were pristine carbon nanotubes, oxidized CNTs (CNTs‐O), pristine graphene nanoplatelets (GNPs‐P), and oxidized graphene nanoplatelets (GNPs‐O). The characteristics and performances of pure and blended membranes were investigated based on their permeability, porosity, morphology, and hydrophobicity. Longer air contact time during membrane preparation resulted in lower membrane permeability, hydrophobicity, and porosity. All fabricated membranes tended to have channelled sponge‐like structure, and highest permeability was attributed to the PES/GNPs‐O membrane.

Monolayer porphyrin assembled SPSf/PES membrane reactor for degradation of dyes under visible light irradiation coupling with continuous filtration✰

Porphyrin-based catalytic oxidation of hydrocarbon bonds is considered to be the most representative biomimetic catalysis. To mimic the biomimetic catalytic oxidation of nature under illumination of visible light, a monolayer of meso-tetrakis (1-methylpyridinium-4-yl) porphyrin immobilized sulfonated polysulfone/ polyethersulfone blend membrane (TMPyP@SPSf/PES) was prepared via a facile electrostatic assembly method. The visible light response region of TMPyP was expanded after it was immobilized on the SPSf/PES membrane surface, which resulted in the increase of the photocatalytic performance, and the Rhodamine B (RhB) degradation was increased from 30.0% to 93.4%. A photocatalytic membrane reactor (PMR) equipped with TMPyP@SPSf/PES membrane was employed for RhB treatment under continuous flow filtration coupling with photocatalysis, and the optimized degradation was up to 98.3%. Moreover, the TMPyP@SPSf/PES membrane can be reused for photocatalytic degradation of RhB after regeneration in TMPyP solution. More importantly, the TMPyP@SPSf/PES membrane can also efficiently degrade other cationic and anionic dyes (such as degradation of methylene blue 99.1%, acid fuchsin 96.8%). Finally, the oxidation mechanism and degradation pathway of RhB were further investigated by electron spin resonance (ESR), ultra-performance liquid chromatography and high-definition mass spectrometry (UPLCHDMS) and gas chromatography-Mass spectrometry (GC–MS). It was revealed that the photogenerated hole (h+), superoxide radical (·O2−), and singlet oxygen (1O2) controlled the oxidation process. The degradation of RhB includes N-de-ethylate, wrecked of chromophore structures and opening-ring of benzene.

Improving the permeability and antifouling property of PES ultrafiltration membranes using the drying method and incorporating the CuO-ZnO nanocomposite

In this research, three techniques to control the permeability and the antifouling property of microporous PES membranes fabricated by the phase inversion and posterior drying have been reported. The three explored methods included incorporating the CuO-ZnO nanomaterial in the PES matrix, altering the solvents filling the pores before drying (water, ethanol, isopropanol and 50% acetone/water), and changing the drying temperature from room temperature to 70 °C. Based on the obtained results, it was found that varying the drying solvents and increasing the drying temperature had a tangible effect on the permeability and antifouling property of the bare and blended polyethersulfone (PES) membranes; this, in turn, resulted in improving the pure water flux from 39.3 to 406 kg/m2h. Moreover, addition of the CuO-ZnO nanomaterial in the optimum content (0.2 wt.%) to the PES matrix in wet membranes led to the growth of 47.2% in the permeability and the increase of the flux recovery ration (FRR) to the highest value. However, this addition did not lead to the proposed effect in the case of the dried membranes.

Development of a new blended polyethersulfone membrane for dye removal from synthetic wastewater

The wastewater produced from various industries like textile, paper, rubber, leather, plastics, cosmetics, pharmaceuticals contains many dyes. Most commonly found dyes in these effluents are Orange G and Methylene blue. These dyes are toxic and are harmful to the environment as well as humans. Hence they need to be removed from the wastewater. Polyethersulfone (PES) membranes are most widely used in ultrafiltration separation processes. Enhancement in membrane permeability and improving the rejection capabilities of the membrane is a key challenge faced by membrane researchers. The current works represent the effect of Barium Chloride blending on separation performance of PES membranes. Through systematic experimental studies, this research work aims to fabricate Polyethersulfone (PES) based membranes and to investigate their efficiency in removing Orange G and Methylene blue from synthetic wastewater. Five different membranes, one of which is a pristine PES membrane and four others made of PES blended with different wt % of Barium Chloride were synthesized in our lab by phase inversion method. The characterization was carried for these fabricated membranes for various properties like membrane morphology, surface hydrophilicity, porosity, and pure water flux. It was evident from the experimental results that PES blended with BaCl2 membranes showed better dye separation efficiency in comparison with the pristine PES membrane. Also, out of the four blended membranes, the one with 2 wt % BaCl2 showed the highest pure water flux, permeate flux, dye rejection, lowest contact angle and the best porosity. The above experimental observations indicate that the UF PES membranes blended with 2 wt % BaCl2 can be a viable alternative membrane for the separation of dyes from industrial water.

New membranes based on polyethersulfone – SlipSkin™ polymer blends with low fouling and high blood compatibility

Hemodialysis is an important therapy for treating patients with End Stage Renal Disease (ESRD). These patients visit the hospital 3 times a week and each time their blood is cleansed during 4-hour dialysis sessions using a hollow fiber membrane module; also called artificial kidney. This device mainly achieves removal of small water-soluble toxins and a limited number of middle molecules. To improve the clearance of toxins, especially middle molecules and protein bound toxins, longer treatment via nocturnal dialysis and/or the application of portable/wearable artificial kidney is required. Such therapies require application of membranes with very low fouling and very good blood compatibility. Current membranes often contain hydrophilic additives which could elute during sterilization processes and/or during long-term filtration. In this study, we propose a simple method for developing low fouling blood compatible membranes by blending of polyethersulfone (PES), a material already used for fabrication of dialysis membranes, with small amounts of SlipSkin™ (SS), a blood compatible random copolymer of hydrophilic N-vinylpyrrolidone (NVP) and hydrophobic N-butylmethacrylate (BMA). Our results show that membranes with 2 wt% of SS have high fouling resistance to proteins and middle-size molecules and very good blood compatibility, making these membranes promising for application in dialysis therapy.

An oil/water separation nanofibrous membrane with a 3-D structure from the blending of PES and SPEEK

A new nanofibrous membrane (NFM) was prepared by blending polyethersulfone (PES) and sulfonated poly(ether ether ketone) (SPEEK) via electrospinning. The membrane exhibits good thermal stability and high mechanical strength. The hydrophilicity of the membrane could be controlled by adjusting the mass ratio of PES to SPEEK. PES acts as the backbone fiber and provides high mechanical strength, while SPEEK provides hydrophilic functional groups due to the strong hydrophilicity of the sulfonic group. The test results show that the composite NFM integrates the advantages of the two polymers. Simple adjustment of the weight ratios of the two polymers can enable an adjustable flux so that the membrane can be used for different kinds of oil/water separation. The results show that NFMs can not only separate immiscible oil/water systems but also separate oil-in-water emulsions. The immiscible oil/water separation process was driven only by gravity and had a high flux of 1119.63 Lm−2 h−1. This separation process conserves energy, which is beneficial for environmental protection. The separation flux of the oil-in-water emulsion was 758.71 Lm−2 h−1 bar−1 based on measurements under different pressures, and the separation purity total organic carbon was below 50 ppm. This work indicates that a membrane comprised of PES and SPEEK has excellent performance and can be used in different fields.

Phase structure and fracture toughness of the polyethersulfone-modified bismaleimide resin

Although bismaleimide (BMI) resins have been widely used for aerospace applications, owing to their good thermal stability, humidity resistance and excellent mechanical property, they are usually brittle due to high crosslinking density and vulnerable to cracking. Hence enhancement in fracture toughness is desired. Polyethersulfone (PES) is a kind of high-performance thermoplastic materials. The blends of PES and BMI were initially homogeneous solutions but become separated in phases during the polymerization of a thermoset. The morphologies of the BMI/PES resin system were studied. The effect of phase structure on the final mechanical properties was investigated

Improved fracture toughness of carbon fiber fabric/epoxy composite laminates using polyether sulfone fibers

This study demonstrated that the addition of dissolvable polyether sulfone fibers to the interlaminar area of carbon fiber/epoxy composites can effectively increase the toughness with very high accuracy. Resin film infusion (RFI) is used to fabricate composite structures. RFI was applied to obtain polyether sulfone as an interleaf of chopped fibers between fabric piles of carbon fibers. The thermoplastic polyether sulfone fiber dissolved in the epoxy when it was cured at a high temperature. A phase-separated morphology with a polyether sulfone-rich secondary phase was formed during the curing process. Experimental results indicated that G Ic, which is the average value of Mode-I fracture toughness, was increased fivefold with the addition of 10 wt% polyether sulfone fiber (with respect to the gross content of the matrix). No detrimental effects were observed in other characteristics such as thermal stability, Young’s modulus, and tensile strength. In addition, the thermal and mechanical characteristics of neat epoxy–polyether sulfone blends were analyzed for comparison.

Development of high flux nanofiltration membranes through single bilayer polyethyleneimine/alginate deposition

The aim of this study is to prepare high flux, stable, antifouling nanofiltration membranes through single bilayer polyelectrolyte deposition. To this end, a tight ultrafiltration support membrane was prepared from a polysulfone/sulfonated polyethersulfone blend. Deposition of a polyethyleneimine and alginate pair on this support has reduced the molecular weight cut off from 6 kDa to below 1 kDa. The pure water permeability and polyethylene glycol 1000 rejection of the coated membrane were found to be 15.5 ± 0.3 L/m2·h·bar and 90 ± 0.6%, respectively, by setting the deposition pH for each layer to 8 and the ionic strengths to 0.5 M and 0 M. This membrane has exhibited significantly higher permeability than commercial membranes with the same molecular weight cut off, retaining 98% of the initial flux during 15 h filtration of bovine serum albumine. In addition, the membrane has been able to completely remove anionic dyes from aqueous solution by showing 99.9% retentions to Reactive red 141, Brilliant blue G and Congo red with a 2 bar transmembrane pressure. High flux and membrane stability in acidic and salty environments have been achieved when deposition conditions favor high adsorption levels for the first layer and strong ionic cross-linking between the carboxyl group on the alginate and the amine groups on the polyethyleneimine.

Application of silica and germanium dioxide nanoparticles/ polyethersulfone blend membranes for removal of emerging micropollutants from water

One of the current global issues of increasing environmental-health concern is the ubiquitous occurrence of emerging micropollutants (EMPs) in aquatic environments. Among these EMPs, bisphenol A (BPA), technical 4-nonylphenol (NP), tonalide (AHTN), carbamazepine (CBZ), caffeine (CAF) and galaxolide (HHCB) find their way into aquatic environments as a result of their ever increasing production and consumption coupled with their incomplete removal in conventional water and wastewater treatment plants. This study fabricated silicon dioxide (silica) (SiO2) and germanium dioxide (GeO2) embedded polyethersulfone (PES) blend membranes using phase inversion method for the removal of EMPs from water samples collected from North West Province, South Africa. The EMPs were extracted and enriched by auto-trace solid-phase extraction and analyzed using comprehensive two dimensional gas chromatography coupled to time of flight mass spectrometry (GCxGC-TOFMS). The fabricated membranes' permeation properties were determined by computing the pure water flux and EMPs' rejection. The water flux was observed to increase with increase in transmembrane pressure as well as increase in SiO2 and GeO2 nanoparticle loadings in the polymer matrices. Compared to the pristine PES, the contact angles for the SiO2/PES and GeO2/PES membranes were much lower, showing increased hydrophilicity of the membranes with increase in SiO2 and GeO2 nanoparticle loadings in the matrices. The mean EMPs' concentrations (ng/L) ranges in the feed were found to be: BPA (5.19 ± 0.8 to 53.60 ± 4.25), CAF (6.09 ± 0.00 to 49.96 ± 3.45), CBZ (0.68 ± 0.00 to 3.06 ± 0.74), HHCB (21.31 ± 4.24 to 13.31 ± 14.8), AHTN (8.31 ± 2.23 to 141.82 ± 21.70), and NP (0–174.99 ± 14.5). Even though SiO2/PES membranes showed slightly higher EMPs' removal efficiencies than their GeO2/PES counterparts, both membranes showed the highest and lowest removal efficiencies range of 97.85–99.00% (for HHCB) and 87.42–93.00% (for CAF), respectively. The results showed superiority in capability of the fabricated nanocomposite membranes in removing EMPs from water.

Hollow Fiber Membranes of Blends of Polyethersulfone and Sulfonated Polymers.

Hollow fiber membranes (HFM) are fabricated from blend solutions of a polyethersulfone (PESU) with a sulfonated PESU (sPESU) or a sulfonated polyphenylenesulfone (sPPSU). The influence of different additives in the dope solution and different bore fluids on the HFM are studied. The addition of poly(sodium 4-styrene sulfonate) (PSSNa)/ethylene glycol (EG) to the dope solution results in an increased water flux of the HFM compared to its counterparts without this additive system. The morphology of the hollow fibers is examined by scanning electron microscopy (SEM). The inner surface of the hollow fibers is studied by X-ray photoelectron spectroscopy (XPS), and it is found that water permeation through the hollow fiber membranes is facilitated due to the change in morphology upon the addition of the PSSNa/EG additive system, but not by the presence of hydrophilic sulfonic acid groups on the membrane surface.

Titanium dioxide nanoribbons/multi-walled carbon nanotube nanocomposite blended polyethersulfone membrane for brackish water desalination

A series of titanium dioxide nanoribbons (TNRs)/multi-walled carbon nanotubes (MWCNTs)/polyethersulfone (PES) blend membranes with different proportions of TNRs/MWCNTs were synthesized via phase inversion method. The nanocomposite (TNRs/MWCNTs) prepared by hydrothermal method followed by chemical vapor deposition (CVD). Energy dispersive X-ray (EDX) analyses and X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) used for characterizing the nanocomposite. The characterization revealed that the nanocomposite consists of a single phase of TiO2-B and multi-walled carbon nanotubes. The mass ratio of TNRs/MWCNTs is 1:1. The morphology of TiO2-B is a nanoribbons structure with porous pits on its surface. Multi-walled carbon nanotubes (MWCNTs) grow on these nanoribbons and form a network structure-like. The influence of nanocomposite incorporation on the morphology, porosity, contact angle, mechanical properties, and performance of the prepared membranes was investigated as a function of pure water flux and salt rejection %. The hydrophilicity is increased by increasing the nanocomposite content whereas the contact angle and porosity decreased. The SEM images showed that the spongy-like structure of bare-PES is changed by incorporation of TNRs/MWCNTs to a macro-void structure. The nanocomposite reinforces and enhances the mechanical properties of the synthesized membranes. The tensile strength increased from 45.7 to 96.6 kg/cm2 by blending 0.5 wt% TNRs/MWCNTs. Also, the incorporation of TNRs/MWCNTs increases the ac electrical properties of the membrane regarding the conductivity (σ), dielectric constant (έ) and dielectric loss (ε″). The membrane performance was tested using synthetic solution with a salinity of 2000, 5000, 7000, and 20,000 mg/l NaCl. The test is carried out at low-pressure reverse osmosis system (LPRO). The highest average salt rejection of membranes was 99.54%, 99.84%, 98.53%, and 94.06%, respectively with the addition of 0.5% of TNRs/MWCNTs, while the average salt rejection was 61.63%, 50.9%, 41.7%, and 75% using bare-PES. The anti-fouling nature and dye removal for all membranes were tested. The flux recovery ratio (FRR) with (PES/0.5 wt% of TNRs/MWCNTs) membrane reach 89% while the bare-PES showed 58%. In addition, the modified membranes showed high removal of 50 mg/l Congo red dye. (PES/0.5 wt% of TNRs/MWCNTs) rejected 98.1% of the dye while the bare-PES rejected 68.14%. The 0.5 wt% of TNRs/MWCNTs embedded to PES considered the best composite content.

Enhancement of fuel cell properties in polyethersulfone and sulfonated poly (ether ether ketone) membranes using metal oxide nanoparticles for proton exchange membrane fuel cell

The proton exchange membrane (PEM) was synthesized using polyethersulfone (PES), sulfonated poly (ether ether ketone) (SPEEK) and nanoparticles. The metal oxide nanoparticles such as Fe3O4, TiO2 and MoO3 were added individually to the polymer blend (PES and SPEEK). The polymer composite membranes exhibit excellent features regarding water uptake, ion exchange capacity and proton conductivity than the pristine PES membrane. Since the presence of sulfonic acid groups provides by added SPEEK and the unique properties of inorganic nanoparticles (Fe3O4, TiO2 and MoO3) helps to interconnect the ionic domain by the absorption of more water molecules thereby enhance the conductivity value. The proton conductivity of PES, SPEEK, PES/SPEEK/Fe3O4, PES/SPEEK/TiO2 and PES/SPEEK/MoO3 membranes were 0.22 × 10−4 S/cm, 5.18 × 10−4 S/cm, 3.57 × 10−4 S/cm, 4.57 × 10−4 S/cm and 2.67 × 10−4 S/cm respectively. Even though the blending of PES with SPEEK has reduced the conductivity value to a lesser extent, hydrophobic PES has vital role in reducing the solvent uptake, swelling ratio and improves hydrolytic stability. Glass transition temperature (Tg) of the membranes were determined from DSC thermogram and it satisfies the operating condition of fuel cell system which guarantees the thermal stability of the membrane for fuel cell application.

Fabrication of Polyether Sulfone Blend Imprinted Membranes for Selective Adsorption of p-hydroxybenzonic from Salicylic Acid

Highly selective polyether sulfone (PES) blend imprinted membranes for template p-hydroxybenzonic (p-HB) were synthesized by phase inversion imprinting technique using polybenzimidazoles (PBI) as a functional polymer and nanosized Al2O3 as the additives. The SEM analysis showed that cross-sectional morphology of membranes were strongly influenced by the content of nano-sized Al2O3. Compared with PES1-MIM, PES2-MIM and PES4-MIM, the PES3-MIM containing 2.0 wt.% nano-sized Al2O3 exhibited higher membrane flux, kinetic equilibrium adsorption value, binding capacity and better selectivity for p-HB. The experimental data of adsorption kinetic were well fitted to the pseudo-secondorder kinetic model using multiple regression analysis. Static adsorption isotherm experiments exhibited that the PES3-MIM had the maximum adsorption capacity for p-HB. Moreover, selective experiment showed that the selectivity coefficients of PES3-MIM for p-HB relative to salicylic acid (SA) was 3.670, showing that PES3-MIM had excellent binding affinity and selectivity for separating p-HB form p-HB-contained aqueous solution.

Effect of Casting Conditions on SMM Blended Polyethersulfone Hydro–Phobic/–Philic Composite Membranes: Characteristics and Desalination Performance in Membrane Distillation

This study aims at further improvement and development of the novel hydro–phobic/–philic composite membranes which are made specifically for membrane distillation (MD). This was attempted by studying the effect of the casting conditions during the membrane preparation process by the phase inversion method. Two variables were chosen to study, which are the evaporation time before gelation and the gelation path temperature. Some of the membranes were allowed to evaporate at room temperature for 2 or 3 minutes to study the effect of evaporation time. The temperature of the gelation path was varied to 4°C, 20°C or 60°C in order to study the gelation path temperature effect. The prepared membranes were characterized using gas permeation test, measurement of the liquid entry pressure of water (LEPw), X–ray photoelectron spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM). The effects of the casting conditions on the membrane morphology were identified, which enabled us to link the membrane morphology to the membrane performance. The membranes were then tested for desalination of 0.5 M NaCl solution by direct contact membrane distillation (DCMD) and the results were compared to commercial polytetraflouroethylene (PTFE) membrane. It was found that the membrane which was prepared with no evaporation time produced better flux than those with evaporation time. Regarding the gelation path temperature; the membrane prepared with gelation path temperature of 4°C was better than those prepared with gelation path temperature of 20 or 60°C. It should be emphasized that the DCMD flux of the membranes prepared with no evaporation time or with a gelation path temperature of 4°C was superior to the commercial one. Furthermore, all the prepared membranes were tested successfully for the desalination application. In other words, no NaCl was detected in the permeate.

Integrating seawater desalination and wastewater reclamation forward osmosis process using thin-film composite mixed matrix membrane with functionalized carbon nanotube blended polyethersulfone support layer

Thin-film composite mixed matrix membrane (TFC MMM) with functionalized carbon nanotube (fCNT) blended in polyethersulfone (PES) support layer was synthesized via interfacial polymerization and phase inversion. This membrane was firstly tested in lab-scale integrating seawater desalination and wastewater reclamation forward osmosis (FO) process. Water flux of TFC MMM was increased by 72% compared to that of TFC membrane due to enhanced hydrophilicity. Although TFC MMM showed lower water flux than TFC commercial membrane, enhanced reverse salt flux selectivity (RSFS) of TFC MMM was observed compared to TFC membrane (15% higher) and TFC commercial membrane (4% higher), representing membrane permselectivity. Under effluent organic matter (EfOM) fouling test, 16% less normalized flux decline of TFC MMM was observed compared to TFC membrane. There was 8% less decline of TFC MMM compared to TFC commercial membrane due to fCNT effect on repulsive foulant–membrane interaction enhancement, caused by negatively charged membrane surface. After 10 min physical cleaning, TFC MMM displayed higher recovered normalized flux than TFC membrane (6%) and TFC commercial membrane (4%); this was also supported by visualized characterization of fouling layer. This study presents application of TFC MMM to integrated seawater desalination and wastewater reclamation FO process for the first time. It can be concluded that EfOM fouling of TFC MMM was suppressed due to repulsive foulant–membrane interaction.

An efficient nanofiltration membrane based on blending of polyethersulfone with modified (styrene/maleic anhydride) copolymer

In this study, styrene–maleic anhydride (SMA) copolymer was modified by ring opening reaction of its anhydride groups with diethanolamine (DEA). The modified SMA copolymer was blended in different concentrations (2.5, 4 and 5.5 %) with Polyethersulfone (PES) to improve the hydrophilicity of PES membranes and the corresponding blend membrane was prepared through phase inversion. The influence of SMA copolymer on morphology, mechanical properties, water flux, rejection and anti-fouling properties of blend membrane were investigated. The modified SMA and their composition were confirmed by FT-IR and 1HNMR techniques. The asymmetric structure of membrane was revealed by SEM. The water flux and contact angle results show that the hydrophilicity of membrane surface was increased by addition of SMA copolymer. The better anti-fouling properties of the PES/modified SMA blend membranes in comparison with the PES membrane also confirmed that the hydrophilicity of blend membrane enhances.