Commercial Polyethersulfone Membrane Research Articles

Collagen fiber membrane as multi-functional support enabled rational design of ultrahigh-flux separation membrane for the remediation of oil contamination in water

Membrane separation is a promising approach for the remediation of oil contamination in water. High-flux separation of membrane relies on the rational design of ultrathin active layer to significantly reduce mass transfer distance for achieving high separation flux, while the ultrathin active layer is usually fragile with poor mechanical strength, which has to be supported on a support. Herein, we employed collagen fiber membrane (CFM) as multi-functional support for the in-situ growth of polyacrylonitrile (PAN) layer by electrospinning to prepare the high-performance PAN/CFM composite membrane. Due to the amphiphilic nature and strong capillary effect, CFM played the role as multi-functional support to provide separation effectiveness and boosted separation flux. The PAN/CFM composite membrane enabled ultrahigh separation flux (e.g., 51751.59 L m−2 h−1 bar−1) to a variety of oil-in-water emulsion, which was one order of magnitude higher than that of commercial polyethersulfone membrane and 1.86-fold to that of cellulose acetate membrane. Furthermore, the PAN/CFM composite membrane retained high separation flux (e.g., 11046.97 L m−2 h−1 bar−1) during the 5th separation cycle, providing appreciable anti-fouling capability. Therefore, our findings provided a promising way to effectively resolve the problem of oil contamination in water.

Valorisation of sodium lignosulfonate by ultrafiltration of spent sulphite liquor using commercial polyethersulfone membrane

ABSTRACT Ultrafiltration of spent sulphite liquor, generated from a laboratory sulphite pulping using chopped stems of Prosopis juliflora, was carried out to recover sodium lignosulfonate (SLS). A commercial hydrophilised polyethersulfone flat-sheet membrane with a molecular weight cut-off of 5 kD was used for the experiments. Effects of the feed dilution factor on the permeate flux were observed, and actual solute rejection coefficients were investigated due to the formation of the concentration polarised layer on the membrane surface. In addition, flux decline and the fouling index of the membrane were determined under the present experimental conditions. SLS obtained in the reject stream was characterised following UV–VIS and nuclear magnetic resonance spectroscopy. The spectroscopic analysis confirmed the reduction of the lignin and hemicelluloses component of wood sample effectively into SLS during sulphite pulping with a considerable degree of similarity with the control sample. The results could be useful as guidelines for the scale-up of SLS production and simultaneous treatment of sulphite liquor from the paper and pulp industry.

Physical and Mechanical Properties of Hollow Fiber Membranes and Technological Parameters of the Gas Separation Process.

The porous layer of composite and asymmetric hollow fiber membranes acts as a support and is exposed to strong mechanical stresses. The effect of external pressure on the polymer structure and, as a consequence, the separation characteristics of the membrane remains unsolved. Based on the solution of the Lamé approach to the calculation of the stress state of a hollow cylinder, a method of calculation was proposed for hollow fiber membranes. Calculations were based on the approximation of the isotropic nature of the physical and mechanical characteristics of the selective layer and substrate. Permissible deformation of the membrane’s selective layer was determined from the linear sector of strain-on-stress dependence, where Hooke’s law was performed. For these calculations, commercial polyethersulfone membranes were chosen with an inner and/or outer selective layer and with the following values of Young’s modulus of 2650 and 72 MPa for the selective and porous layers, respectively. The results obtained indicate that the dependence of the maximum allowable operating pressure on the substrate thickness asymptotically trends to a certain maximum value for a given membrane. Presented data showed that membranes with outer selective layer can be operated at higher working pressure. Optimal parameters for hollow fiber gas separation membrane systems should be realized, solving the optimization problem and taking into account the influence of operating, physicochemical and physicomechanical parameters on each other.

Lignin separation from black liquor by mixed matrix polysulfone nanofiltration membrane filled with multiwalled carbon nanotubes

Carbon nanotubes (CNT)/polysulfone (PSf) mixed matrix membranes (MMM) were prepared by the non-solvent induced phase inversion method and applied in the separation of lignin from black liquor (BL). Three different type of membranes were developed to minimise the fouling phenomenon, which is one of the major concerns regarding the application of polymeric membranes for BL fractionation. The effect of CNT on the filtration and morphological properties were investigated by analyzing pure water flux, porosity, mean pore size, scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy and water contact angle. These analyses indicated that with increasing the nanotubes content (0–0.5%) resulted in an increase of ≈ 3 times in the mean pores size, water flux (14.8–132.5 Lm−2 h−1 at 15 bar), porosity (74.4–79.7%) and reduction of surface roughness of the prepared membranes. The performance of these membranes was analyzed in terms of lignin rejection and fouling resistance using standard lignoboost lignin solution at various pressures and compared with a commercial polyethersulfone membrane. It was observed that reduction in the permeate flux was lowest (~10% at 12 bar) in the 0.5% CNT-based membranes. However, in terms of lignin rejection, the highest (80–98%) and lowest (52–76%) values were achieved with the simple PSf membrane (0% CNT) and 0.1% CNT membrane, respectively. Further, fouling studies showed that through chemical cleaning, the initial flux was completely recovered for CNT-based membranes without disturbing their flux and rejection behavior. Among the 3 types of prepared membranes, 0.5% CNT membranes showed a good balance between permeate flux and lignin rejection. The application of these membranes for nanofiltration of industrial BL, pre-treated by ultrafiltration, allowed to reach 82–84% rejection for lignin and 37–42% for hemicelluloses. This suggests a significant degree of selective separation of lignin from BL using CNT-based MMM.

Evaluation of a quaternized polyethersulfone membrane enhanced with amine functionalized carbon nanotubes for forward osmosis application

Multiwall carbon nanotubes (CNTs) were quaternized with trimethylamine to form an anionic conductive CNTS (QCNTs) then blended with quaternized polyethersulfone membrane (QPES) by phase invasion method to obtain a composite membrane with higher permeation, improved rejection and enhanced antifouling properties for forward osmosis application. The membranes and QCNTs were characterized using SEM, TGA, NMR, Raman and FTIR. The fabricated composite membranes showed that addition of QCNTs can improve membrane basic properties when compared to commercial polyethersulfone membranes. This observed improvement could be attributed to the incorporated oxygen and amine functionalities in the CNTs. The 0.1 wt % QCNTs showed a contact angle of 64, reverse solute flux of 7.4 and 6.2 Lm-2h-1 for NaCl and MgSO4 respectively compared to an original pure water flux of 8.058 Lm-2h-1. Humic acid was used as a foulant, when the composited was fouled using humic acid, the 0.1wt.% QCNTs showed a reverse solute flux of 5.7 and 5.0 Lm-2h-1 respectively at room temperature.

Photoactive polymer membranes for degradation of pharmaceuticals from water

Two different photosensitizer molecules were immobilized on a commercial polyethersulfone membrane by electron beam-mediated grafting. The resulting membrane surface generates singlet oxygen upon activation with light according to the photosensitizer‘s excitation wavelength. Thus, the immobilization procedure results in highly active membrane surfaces. The degradation of different pharmaceuticals (propranolol and ranitidine) by the photoactive membranes was investigated. The activity (singlet oxygen generation rate) and degradation efficiency regarding the two pharmaceuticals was studied next to membrane characteristics (scanning electron microscopy, permeance, contact angle, X-ray photoelectron spectroscopy). The immobilization led to increased surface hydrophilicity and permeance while preserving pore size and morphology. Both photosensitizer membrane systems showed high singlet oxygen generation activity. It was found that propranolol and ranitidine were efficiently converted by singlet oxygen to transformation products, but they were not completely mineralized as monitored by total organic carbon analysis and chromatography.

The interplay role of vanillin, water, and coagulation bath temperature on formation of antifouling polyethersulfone (PES) membranes: Application in wood extract treatment

In this study vanillin was tested as the hydrophilicity promoter in a PES membranes to improve the feasibility of the membranes in the treatment of a biorefinery stream, namely a pressurized hot water extract (PHWE). The commercial PES membranes are typically prepared by phase inversion technique and thus, phase inversion is also used in this study. The ultimate structure of the phase inversion prepared membranes is asymmetric and it can be affected by various key parameters such as the temperature and the concentration of the PES solution, the solvent and additives which are used in PES solution, the coagulation bath temperature as well as the thickness of the cast PES film. In the present study, the effect of vanillin (0–6 wt.%) as a hydrophilic promoter agent, water as strong non-solvent additive in dope solution (0–2 wt.%) and coagulation bath temperature (CBT) on the formation of PES membranes was investigated in order to improve the understanding on the manufacturing of PES/vanillin membranes. The mentioned fabrication parameters were optimized and their effects on the membrane morphology, hydrophilicity, thickness, PHWE permeability, fouling and rejection properties were sequentially analyzed. It can be concluded that a small quantity of vanillin and water together in dope solution can preferably change the membrane morphology and increase the surface hydrophilicity and thus lead to formation of membrane with better wood extract permeability and antifouling characteristics.

Performance of Ultrafiltration–Ozone Combined System for Produced Water Treatment

Oil exploration waste, also called produced water, contains hazardous pollutants, such as benzene; benzene, toluene, and xylene (BTX); naphthalene, phenanthrene, and dibenzothiophene (NDP); polyaromatic hydrocarbons (PAHs); and phenol. Produced water is characterized by high chemical oxygen demand (COD) and oil content, which exceed the standard limits of regulation. In this study, the combination of ultrafiltration (UF) and ozone pre-treatment and post-treatment were applied for treatment of produced water to minimize its environmental impact. Produced water and membrane were characterized, and their ultrafiltration performance for removal of oil content, benzene, toluene, xylene, and COD. Two commercial Polyethersulfone membranes, with molecular-weight cut-off values of 10 and 20 kDa, were used. The membrane flux profile illustrated that ozone pre-treatment had higher normalized flux than UF only. Separation performance was evaluated based on flux profile and removal of COD, oil and grease content, toluene, and xylene. Significant finding was found where the combination of UF with ozone pre-treatment and post-treatment could significantly eliminate COD, oil content, toluene, and xylene. The rejection of these components was found higher than conventional process, which was in the range of 80 % to 99 %. In addition, almost oil and grease can be removed by using this combined system. Permeate quality of this system confirmed the acceptable level as water discharge.

Biopolymer extracted from Moringa oleifera Lam. in conjunction with graphene oxide to modify membrane surfaces

ABSTRACT A novel modification through pressurized filtration technique of commercial polyethersulfone membranes was proposed using a biopolymer extracted from Moringa oleifera Lam. (MO) along with graphene oxide (GO), in order to decrease fouling and improve the membrane selectivity for the removal of methylene blue dye. The effect of these agents over the morphology and performance of the membranes were studied through the evaluation of permeability, dye removal and fouling parameters. The characterization of the membrane indicates a significant decrease in pore size, as confirmed by the filtration experiments. Also, according to FTIR and SEM analysis the modification was effectively accomplished. All modified membranes presented low fouling rates (<10.55%) and high dye removal rates (from 2.85% to 96.73%). Furthermore, it is the first time that MO has been used as a natural polymer to improve and confer new characteristics on membranes, creating new possibilities for further study of this promising environment-friendly biopolymer in membrane separation processes.

Designing fouling-resistant clay-embedded polyelectrolyte multilayer membranes for wastewater effluent treatment

This work explores the applicability of clay-polyelectrolyte based hybrid thin films to develop fouling resistant membrane surfaces for wastewater treatment applications. Clay nanoplatelets were layered on a commercial polyethersulfone membrane in conjunction with two oppositely charged polyelectrolytes via the aqueous-based layer-by-layer (LbL) assembly technique. These hybrid nanostructured membranes showed a high degree of fouling resistance as compared to other commercial membranes and the pure polyelectrolyte multilayer (PEM) membranes, when tested against an electrocoagulation-treated high strength wastewater. With the deposition of just 2.25 quadlayers, the clay-PEM (c‐PEM) membranes demonstrated good anti-fouling properties. On crosslinking the polyelectrolytes, the c‐PEM hybrid membranes showed higher reduction in the chemical oxygen demand (COD) value and enhanced fouling resistance as compared to their uncrosslinked counterparts, the pure PEM membranes (both uncross linked and crosslinked) and the bare membrane. However, the high fouling resistance of the c‐PEM membranes was attained at the cost of compromising the high initial flux value of the underlying membrane. Several possible optimization strategies have therefore been suggested in this paper, which can potentially increase the flux of the modified membranes. This work, for the first time, demonstrated an attempt to evaluate the performance of clay-polyelectrolyte nanocomposite membranes against a real wastewater effluent.

A method for measurement of free cadmium species in waters using diffusive gradients in thin films technique with an ion-imprinted sorbent

A diffusive gradients in thin films (DGT) device for the analysis of free Cd(II) species, based on Cd(II) ion-imprinted sorbent (IIS) as the binding agents and commercial polyethersulfone membrane (PES) as diffusion layer, was developed (PES/IIS-DGT). DGT time-series experiments showed that the mass of free Cd(II) species accumulated by PES/IIS-DGT was linear vs. time (R2 = 0.9953) and the concentration of free Cd(II) species by PES/IIS-DGT was in good agreement with the total dissolved concentrations of free Cd(II) species in simple synthetic solutions where free ionic species dominated. PES/IIS-DGT performance was independent in the range of pH 4.5–7.5 and ionic strength range from 1.0 × 10−3 to 0.7 mol L−1. The measurement of free Cd(II) species in synthetic solution containing different concentrations of ligands by PES/IIS-DGT showed an excellent agreement with the value measured by Cd(II) ion selective electrodes (Cd-ISE), indicating that PES/IIS-DGT method is more suitable than Cd-ISE for the measurement of low concentration of free Cd(II) species due to the enrichment of IIS for the analytes.

Treatment of laundry wastewater using polyethersulfone/polyvinylpyrollidone ultrafiltration membranes

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 10kDa in ultrafiltration. Operating parameters The influence of transmembrane pressure (TMP) and stirring speed on laundry wastewater flux was investigated. A higher permeate flux of 55.2L/m2h was obtained for modified PES membrane with high concentration of PVP at TMP of 500kPa and 750rpm 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.

Influence of bentonite in polymer membranes for effective treatment of car wash effluent to protect the ecosystem

In this study, modified polyethersulfone (PES) and cellulose acetate (CA) membranes were used in the treatment of car wash effluent using ultrafiltration. Hydrophilic sulfonated poly ether ether ketone (SPEEK) and bentonite as nanoclay were used as additives for the PES and CA membrane modification. Performances of modified membranes were compared with commercial PES membrane with 10kDa molecular weight cut off (MWCO). The influencing parameters like stirrer speed (250–750rpm) and transmembrane pressure (100–600kPa) (TMP) were varied and their effects were studied as a function of flux. In the treatment of car wash effluent, a higher permeate flux of 52.3L/m2h was obtained for modified CA membrane at TMP of 400kPa and stirrer speed of 750rpm. In comparison with modified PES membrane and commercial PES membrane, modified CA membranes showed better performance in terms of flux and flux recovery ratio. The highest COD removal (60%) was obtained for modified CA membrane and a lowest COD removal (47%) was observed for commercial PES membrane. The modified membranes were better at removing COD, turbidity and maintained more stable flux than commercial PES membrane, suggesting they will provide better economic performance in car wash effluent reclamation.

Fabrication of ultra-thin polyelectrolyte/carbon nanotube membrane by spray-assisted layer-by-layer technique: characterization and its anti-protein fouling properties for water treatment

Polyethersulfone (PES) membranes are extensively used as ultrafiltration (UF) membrane owing to their superior thermal, mechanical, and chemical stability. However, commercial PES membranes are more prone to fouling, which contributes to severe decline in permeate flux with operation time. To improve the commercial PES UF membrane anti-protein fouling properties, negatively charged functionalized multi-walled carbon nanotube (f-MWCNTs), blended poly(sodium 4-styrenesulfonate) (PSS), and positively charged poly(diallyldimethylammonium chloride) (PDDA) were deposited on 20 kDa PES substrate through spray-assisted layer-by-layer (LbL) technique. Further cross-flow UF tests were conducted with bovine serum albumin (BSA) as model protein. The total flux loss results show that surface-modified PES membranes are less susceptible to protein fouling by one-hour BSA filtration. Moreover, flux recovery ratios show that 20-min de-ionized (DI) water flushing is effective to restore water flux of the prepared membrane without aggressive chemical cleaning. Based on the experimental results, the excellent anti-fouling properties render the prepared membranes suitable for recycling utilization.

Hydrolysis of Lactose from Cheese Whey Using a Reactor with β-Galactosidase Enzyme Immobilised on a Commercial UF Membrane

Abstract In this study, β-galactosidase enzyme from Kluyveromyces fragilis was immobilised on a commercial polyethersulfone membrane surface, 10 kDa cut-off. An integrated process, concerning the simultaneous hydrolysis-ultrafiltration of whey lactose was studied and working conditions have been fixed at 55°C and pH 6.9, the same conditions that are used for the industrial process of protein concentration. For the immobilisation, best results were obtained using 5% (v/v) of glutaraldehyde solution and 0.03 M galactose; the total activity recovery coefficient (TARC) was 44.2%. The amount of immobilised enzyme was 12.49 mg with a total activity of 86.3 LAU at 37°C, using 5% (w/v) lactose solution in phosphate buffer (100 mM pH 6.9). The stability of the immobilised enzyme was approximately 585 fold higher in comparison with the stability of free enzyme. Multipoint covalent immobilisation improves the stability of the enzyme, thereby enhancing the decision to use the membrane as a filtering element and support for the enzyme immobilisation.

Synthesis And Performance Of Thin Film Composite Nanofiltration Polyester Membrane For Removal Of Natural Organic Matter Substances

Nanofiltration (NF) polyester thin-film composite (TFC) membranes have been prepared by interfacial polymerization using commercial polyethersulfone membrane support. At 6% (w/v) triethanolamine (TEAO) concentrations in the aqueous solution and a range of interfacial polymerization times in the organic solution containing trimesoyl chloride (TMC) were studied. Nanofiltration membranes were produced with varying properties through interfacial polymerization technique. The ability to use NF membranes with varying properties will improve overall process efficiency. This study has shown that through interfacial polymerization technique, the variation of reaction time as well as can affect the performance of the membrane produced. As a result, increasing the reaction time resulted in decreasing water permeabilities. Polyester with some amide group produced after interfacial polymerization occurred as shown by FT-IR spectra. Straight lines were obtained between Jw and ΔP and the water flux of distilled water shown that flux is directly proportional to transmembrane pressure (TMP). At low reaction time (5 min), the water flux has no significant effect on water permeance. So, the reaction time has a significant effect on the growth of thin film.

Nanofiltration thin-film composite polyester polyethersulfone-based membranes prepared by interfacial polymerization

Nanofiltration polyester thin-film composite membranes have been prepared by interfacial polymerization using commercial polyethersulfone membrane support. Different monomer bisphenol A (BPA) concentrations in the aqueous solution and various interfacial polymerization times in the organic solution containing trimesoyl chloride (TMC) were studied. The success of the conducted interfacial polymerization procedure was corroborated by FTIR-ATR. Irreversible fouling of both the unmodified polyethersulfone and the modified polyester thin-film composite polyethersulfone membranes have been studied using humic acid model solutions at different pH values. It was observed that polyester thin-film composite membranes exhibited practically no tendency to be irreversibly fouled by humic acid molecules at neutral environment. However, the permeate flux was decreased and the irreversible fouling factor was enhanced with decreasing the pH to a value of 3.

Study of the characteristics and the performance of self-made nanoporous polyethersulfone membranes

Polyethersulfone (PES) membranes were prepared in this study by using the DIPS technique (diffusion induced phase separation) in view of a better insight into the performance of commercial polyethersulfone membranes and a verification for the limited information given by the manufacturer. During this process, a lot of conditions influence the final membrane structure. Beside the choice of the solvent (dimethylformamide (DMF) or N-methyl-pyrrolidone (NMP)), it was shown that the concentration of the polymer and the relative air humidity are the most crucial ones. Optimizing these factors led to reproducible membranes, which were characterized for hydrophobicity, roughness, surface charge and molecular weight cut-off (MWCO). The performance was studied by doing cross-flow filtration experiments with aqueous solutions of uncharged and charged component. Although the self-made membranes were characterized by a larger MWCO in comparison with commercial polyethersulfone nanofiltration membranes, the retention for the self-made membranes was almost equal to or even higher than the commercial membranes in the case of filtrating negatively, respectively, positively charged component. The high retention of the self-made membranes for positively charged component can be explained by adsorption experiments or by surface charge measurements before and after filtration.