Polyethersulfone Hollow Fiber Membranes Research Articles

Enhancing thin-film composite polyethersulfone hollow fiber membranes through alkali-induced interfacial polymerization modification for effective separation of monovalent/divalent salts

Amidst the escalating global water scarcity issues, finding better ways to sustainably treat brackish water and seawater while simultaneously recovering resources becomes increasingly important. In this work, we investigated the fabrication strategies to produce polyethersulfone hollow fiber membranes (PES HFMs) with robust characteristics and uniformly arranged shape. The presence of an air gap (AG) in the dry-wet spinning process facilitates the chain orientation due to the gravitational force and elongational stretch and moisture-induced early phase inversion, therefore preventing corrugations on the shell side. We extensively studied the correlation between HFM spinning parameters and the appearance and disappearance of buckling effects. Moreover, it was proven that the addition of N-methyl-2-pyrrolidone (NMP) to the bore fluid composition prolongs the demixing process, overcoming the HFMs' delamination issue. After optimizing the spinning conditions, a facile alkali-induced interfacial polymerization (IP) was employed to enhance the formation of a selective polyamide (PA) layer on PES HFM substrates. The final membrane made by this modification process, denoted as PES-IP-BOH, exhibits a Na2SO4 rejection higher than 96 %, while maintaining low rejections for other monovalent salts. Accordingly, it achieved a high ideal selectivity of >23 for the selective separation of monovalent and divalent salts.

Integrated membrane packed enzymatic column for the removal of atrazine in wastewater: Experimental, kinetics, breakthrough curves analysis and applicability in real wastewater

The current study explored the performance of a packed bed biocatalytic column equipped with polyethersulfone (PES) hollow fiber membranes and Novoprime base 268 laccase (Lac) for the biotransformation of the recalcitrant herbicide, atrazine (ATZ). Column design parameters: feed concentration (5 mg L −1), flow rate (2 mL min−1) and bed height (14 cm) generated optimum membrane retention (MR) in the fixed bed. A standalone MR system attained >50 % of ATZ retention with a maximum capacity of 170.2 mg g−1 at bed service time of 559 min. Under optimized conditions (50 mg dosage, 5 mg L−1 solution concentration at 25 °C) 66 % degradation efficiency was observed in the laccase-assisted conversion within 24 h. PES-Laccase (PES-Lac) biocatalyst improved the overall degradation efficiency to 86 %, exhibited simple regeneration and satisfactory operational reusability, retaining 46 % activity in the sixth cycle. Overall, the work demonstrated the potential of PES-Lac biocatalytic system to selectively bioremediate ATZ and provided a detailed understanding of the factors influencing its efficiency for applicability in water reclamation.

Fabrication and optimization of PES/PVP hollow fiber membranes using Box–Behnken model and CART algorithm

AbstractThis study focuses on the optimization of polyethersulfone (PES) hollow fiber membranes fabricated with the phase inversion method. A Box–Behnken experimental design was employed with three different PES concentration ratios (11, 14, 17 wt.%), three polyvinylpyrrolidone (PVP) molecular weight ratios (K30/K90 ratios of 6:0, 3:3, 0:6 wt.%), three different bore fluid (BF) composition ratios (water/alcohol ratios of 20:80, 60:40, 100:0), and three different air gap values (24, 37, and 50 cm). The results were analyzed in terms of pure water permeability (PWP) and porosity as optimization parameters using response surface methodology and the classification and regression tree (CART) model. ANOVA results revealed significant effects of PES concentration, PVP molecular weight, and BF composition on the outcomes. After optimization, the maximum PWP and the maximum porosity were obtained as 360.15 L/m2 h bar, 60.57%, respectively. The CART model achieved sufficient accuracy in classifying samples.

A novel organic solvent-free method for manufacturing polyethersulfone hollow fiber membranes using melt extrusion

Hollow fiber membranes are traditionally manufactured using the spinning process, which takes advantage of the phase separation/inversion for the creation of a porous structure. In this work, the use of melt extrusion led to the fabrication of hollow fiber membranes without the use of organic solvents. Following post-treatment, the fabricated partially dense fibers are transformed into porous fibers. In detail, ternary blends of polyethersulfone/poly(ethylene glycol)/poly(N-vinyl pyrrolidone) (PESU/PEG/PVP) were developed by combining a solvent-free liquid mixture of PEG/PVP into PESU. Using a single screw extruder, this blend was melted and extruded using an annular slit nozzle where PEG functioned as a plasticizer, i.e., decreased processing temperatures, while PVP aided in retaining the hollow fiber geometry. These hollow fibers were comprised of uniformly closed pores, occurring due to the expansion and formation of bubbles of evaporating PEG nucleated by PVP during extrusion. By immersing these fibers into an aqueous solution of sodium hypochlorite (NaOCl), PEG and PVP were removed, which led to an open porous structure with pore sizes between 100 nm and 1 μm throughout the membrane. The outer surfaces of the hollow fibers were found to contain a higher PVP content than the inner surface. As PVP and PESU are miscible, i.e., blended in a single phase, treatment with NaOCl led to the creation of open pores on the outer surface with pore sizes between 10 and 150 nm, thus deeming the outer surface functional as a separation layer. The effect of blend composition, extrusion settings, and post-treatment parameters on membrane morphology, water flux, thermal characteristics, and tensile strength was studied, while after the modification, near-pristine PESU membranes were pursued. A water-flux of 28 L/h m2 bar and a molecular weight cut-off (MWCO) of 90%, 75%, and 40% for poly(ethylene oxide) of an average of 1000 kDa, 400 kDa, and 100 kDa molecular weight, respectively, proved that via extrusion it is possible to produce hollow fiber membranes for ultrafiltration without the use of organic solvents.

Impact of support pore properties on the performance of layer-by-layer self-assembly nanofiltration membrane

This paper investigates the impact of the porous structure of the support on the permselectivity and backwash resistance of Layer-by-Layer (LBL) nanofiltration (NF) membranes. Four different polyethersulfone (PES) hollow fiber membranes with varying pore sizes were coated with poly(allylamine hydrochloride)/poly(sodium-4-styrenesulfonate) (PAH/PSS) polyelectrolyte pairs. The study found that adjusting the number of bilayers in the coating process enabled the production of LBL membranes with similar molecular weight cut-off (MWCO) around 250 Da and high Mg2+ rejection of 95 %. However, Na2SO4 rejection decreased as the number of bilayers increased, as the positively charged PAH overcompensated. The study also found that the pore size of the support did not significantly impact the backwash resistance of the LBL membranes, indicating that the polyelectrolyte chains can penetrate through the pores of the supports regardless of pore size. This finding can guide the design of suitable supports for LBL NF membranes with tailored performances.

Use of scanning electron microscopy and energy dispersive X-ray spectroscopy to identify key fouling species during alternating tangential filtration.

Alternating tangential flow filtration (ATF) has become one of the primary methods for cell retention and clarification in perfusion bioreactors. However, membrane fouling can cause product sieving losses that limit the performance of these systems. This study used scanning electron microscopy and energy dispersive X-ray spectroscopy to identify the nature and location of foulants on 0.2μm polyethersulfone hollow fiber membranes after use in industrial Chinese hamster ovary cell perfusion bioreactors for monoclonal antibody production. Membrane fouling was dominated by proteinaceous material, primarily host cell proteins along with some monoclonal antibody. Fouling occurred primarily on the lumen surface with much less protein trapped within the depth of the fiber. Protein deposition was also most pronounced near the inlet/exit of the hollow fibers, which are the regions with the greatest flux (and transmembrane pressure) during the cyclical operation of the ATF. These results provide important insights into the underlying phenomena governing the fouling behavior of ATF systems for continuous bioprocessing.

Analysis of bisphenol-propane in dialyzer and its effect on human body

The effect of trace solvent bisphenol A (BPA) in polyether sulfone hollow fiber membrane Enttex™-16LF (E60) (produced by 3 M) low-throughput dialyzer was tested in this study. Animal experiments were conducted to evaluate its genotoxicity, carcinogenicity, and teratogenicity upon chronic exposure. The dialyzer was operated at 200 mL/min and 400 mL/min and coupled with LC-20AT liquid chromatography to detect BPA, which showed that the BPA content was less than 5 μg/kg/d at both flow rates. In animal experiments, the tolerable intake (T.I.) was calculated to be 0.5 μg/kg/d. With hemodialysis three times per week, the average patient weight was calculated at 70 kg, and the average daily BPA exposure was 0.0306 μg/kg/d. The risk of residual BPA was within the acceptable limit with polyether sulfone membrane Enttex™-16LF (E60) hollow fiber dialyzer from 3 M, without inducing risk for disability, teratogenicity, or genotoxicity.

Molecular Compatibility and Hydrogen Bonding Mechanism of PES/PEI Blends.

The development of high-performance polymer membranes has sparked a lot of attention in recent years. Polymer blending is a potential method of modification. A limitation, however, is the compatibility of blends at the molecular level. In this investigation, polyethersulfone/polyetherimide hollow fiber membranes were prepared by the solution blending method. Compatibility, hydrogen bonding, crystallinity, microstructure, hydrophilicity, mechanical properties, and transmissibility of blended membranes were also characterized. The compatibility and hydrogen bonding action of the two components were confirmed by DSC, FTIR, XPS, and XRD. The structure exhibits a C−H···O interaction motif with the sulfone group acting as a hydrogen bond acceptor from a methyl C−H donor. The π–π stacking between the two polymers arranged molecules more orderly, resulting in enhanced intermolecular interactions. Compared to polyethersulfone hollow fiber membranes, the hydrophilic, mechanical properties, and rejection rate of the blended membranes are more effectively enhanced. Self-assembly of the host polymer with a polymer capable of forming hydrogen bonds to construct controllable blends is a crucial and proven method.

Removal of Organic Dye in Wastewater Using Polyethersulfone Hollow Fiber Membrane

In this study, polyethersulfone (PES) hollow fiber membranes (HFM) were fabricated with different weight percentage (wt. %) of polymer at 16 wt. %, 18 wt. % and 20 wt. %, in order to study the impact of polymer weight percentages on membrane properties and its dye rejection performance. Microfiltration HFM were fabricated by using the laboratory dry-wet spinning method. In order to improve the pore structure of the polymer membrane, 3 wt. % of (PVP) of 8000 M.W. was added in the dope solution. All the fabricated PES hollow fiber membranes were characterized using the Scanning Electron Microscopy (SEM), Atomic Force Microscope (AFM), Fourier Transform Infrared Spectroscopy (FTIR) and the contact angle. The HFM’s performance was evaluated in terms of dye rejection, by using Direct Red 80 dye as substitute of organic dye in wastewater. The results ed that the membrane with higher weight percentage of PES polymer (20 % PES) had thicker separation layer, smoother membrane surface and uniform like pore structures. The membrane with the higher weight percentage of polymer (20% PES) had higher dye rejection percentage (67.33%) and higher permeate flux (10.024 L/m2h) compared to 16 wt. % and 18 wt. %. The results of this study revealed that the weight percentage of polymer in the membrane did affect the membrane properties and its performance.

Human Cholangiocytes Form a Polarized and Functional Bile Duct on Hollow Fiber Membranes.

Liver diseases affect hundreds of millions of people worldwide; most often the hepatocytes or cholangiocytes are damaged. Diseases of the biliary tract cause severe patient burden, and cholangiocytes, the cells lining the biliary tract, are sensitive to numerous drugs. Therefore, investigations into proper cholangiocyte functions are of utmost importance, which is restricted, in vitro, by the lack of primary human cholangiocytes allowing such screening. To investigate biliary function, including transepithelial transport, cholangiocytes must be cultured as three-dimensional (3D) ductular structures. We previously established murine intrahepatic cholangiocyte organoid-derived cholangiocyte-like cells (CLCs) and cultured them onto polyethersulfone hollow fiber membranes (HFMs) to generate 3D duct structures that resemble native bile ducts at the structural and functional level. Here, we established an efficient, stepwise method for directed differentiation of human intrahepatic cholangiocyte organoids (ICOs) into CLCs. Human ICO-derived CLCs showed key characteristics of cholangiocytes, such as the expression of structural and functional markers, formation of primary cilia, and P-glycoprotein-mediated transport in a polarized fashion. The organoid cultures exhibit farnesoid X receptor (FXR)-dependent functions that are vital to liver bile acid homeostasis in vivo. Furthermore, human ICO-derived CLCs cultured on HFMs in a differentiation medium form tubular architecture with some tight, confluent, and polarized monolayers that better mimic native bile duct characteristics than differentiated cultures in standard 2D or Matrigel-based 3D culture plates. Together, our optimized differentiation protocol to obtain CLC organoids, when applied on HFMs to form bioengineered bile ducts, will facilitate studying cholangiopathies and allow developing therapeutic strategies.

In vitro hemocompatibility and hemodialysis performance of hydrophilic ionic liquid grafted polyethersulfone hollow fiber membranes

Polymer-based hemodialyzers have been widely used to treat patients suffered from end stage renal disease clinically. Polyethersulfone (PES) is seen as one of the most important hemodialysis membrane materials. Numerous strategies have been done to increase the hemocompatibility of PES, but molecular chain modification of PES has been seldomly reported. In this work, a hydrophilic ionic liquid (IL) grafted PES (PES-g-IL) was used to prepare the hollow fiber membranes (HFMs). The structure and properties, including hemocompatibility, hemodialysis performance as well as the cytotoxicity of PES-g-IL HFMs were investigated systematically. It was found that PES-g-IL HFMs had higher porosity, lower protein adsorption, less platelet adhesion and longer clotting time than PES HFMs, indicating the enhanced hemocompatibility. Besides, both the toxins removal and BSA rejection of PES-g-IL HFMs were significantly higher than those of PES HFMs. Particularly, the middle molecule uremic toxin (lysozyme) clearance of PES-g-IL HFMs was twice higher than that of PES HFMs. At the same time, the BSA rejection of PES-g-IL HFMs achieved as high as 98%. Moreover, PES-g-IL showed negligible cytotoxicity. It is considered that the grafting of IL changed the microstructure and improved the hydrophilicity of PES-g-IL membranes, leading to the enhanced hemocompatibility, hemodialysis performance and cytocompatibility.

Structured pattern hollow fiber membrane designed via reverse thermally induced phase separation method for ultrafiltration applications

AbstractMembrane fouling is a major problem that hinders the application of the membrane in water filtration. To address this issue, a novel reversed thermally induced phase separation (RTIPS) process is applied to fabricate a patterned polyethersulfone (PES) hollow fiber (HF) membrane using a structured spinneret. Surface patterning could induce turbulence, thereby preventing the accumulation of foulants on membrane surface. The RTIPS method requires lesser material with similar mechanical strength compared to that of conventional TIPS method. The fabrication process is optimized by changing the spinning conditions. A dope composition of 24 wt% PES is chosen to prepare the membrane. The chemical composition of the membrane is confirmed via sophisticated techniques such as Fourier‐transform infrared (FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) images of the sample indicates the successful formation of the pattern on the shell side of the HFs. The prepared patterned HF membranes exhibits a high rejection of 97% of bovine serum albumin (BSA), which is comparable to or higher than that of commercial membranes. Moreover, the patterned membrane demonstrates better performance, thereby confirming the effectiveness of this modification in enhancing the antifouling nature.

Polyethersulfone Hollow Fiber Membranes with Enhanced Hemocompatibility and Hemodialysis Performance by Hydrophilic Ionic Liquid Grafting

Polyethersulfone Hollow Fiber Membranes with Enhanced Hemocompatibility and Hemodialysis Performance by Hydrophilic Ionic Liquid Grafting

In Vitro Hemocompatibility and Hemodialysis Performance of Hydrophilic Ionic Liquid Grafted Polyethersulfone Hollow Fiber Membranes

In Vitro Hemocompatibility and Hemodialysis Performance of Hydrophilic Ionic Liquid Grafted Polyethersulfone Hollow Fiber Membranes

Enhancing water flux and antifouling properties of PES hollow fiber membranes via incorporation of surface‐functionalized Fe3O4 nanoparticles

AbstractBACKGROUNDIn this study, polyethersulfone (PES) hollow fiber membranes incorporated with surface‐functionalized iron oxide (Fe3O4) nanoparticles were developed in order to improve water flux and antifouling properties of PES membrane. Commercial Fe3O4 nanoparticles was coated by polydopamine (PDA), followed by functionalization using (3‐aminopropyl)triethoxysilane (APTES) and sulfonic acid to produce Fe3O4/PDA‐Amine and Fe3O4/PDA‐Sulf nanoparticles, respectively. All the nanoparticles‐modified membranes were synthesized using dope solution composed of different nanoparticles, followed by a series of instrumental characterization and filtration assessments.RESULTSIt is found that the membrane incorporated with Fe3O4/PDA‐Amine exhibited the best filtration performance, achieving water flux of 137.23 L m−2 h−1 bar−1 and bovine serum albumin (BSA) rejection of 92.16%. As a comparison, the pristine PES membrane only showed 82.60 L m−2 h−1 bar−1 and 71.92%, respectively. The membrane with Fe3O4/PDA‐Sulf also showed lower performance, recording 129.88 L m−2 h−1 bar−1 and 88.39%, respectively. The improved performance of the Fe3O4/PDA‐Amine‐modified PES membrane could be attributed to its lowest water contact angle (65.10°), highest porosity (68.14%), ideal pore size (65 nm) as well as good structural integrity. More importantly, the improved surface properties also led to outstanding fouling resistance, achieving flux recovery rate of 97%. This membrane also achieved excellent chemical oxygen demand (95.17%) and color (89.86%) reduction when tested using river water sample.CONCLUSIONOur work demonstrated a simple approach to functionalize the surface of Fe3O4 nanoparticles and showed the effectiveness of the surface‐functionalized Fe3O4 nanoparticles in improving not only the surface properties of PES membrane but also its filtration performance in terms of permeability, rejection and antifouling property. © 2021 Society of Chemical Industry (SCI).

Effect of laminar pulsatile fluid flow on separation of volatile organic compounds from aqueous solution by a hollow fiber membrane-based process

In this study, a laminar pulsatile fluid flow was used for the separation of benzene, toluene, ethylbenzene and xylene isomers (BTEX) from aqueous solutions. The polyethersulfone hollow fiber membrane has been applied to this process. The effects of BTEX concentration, feed, and extraction flow rates were examined. It was found that the application of the pulsatile fluid flow with the frequency of 0.5 Hz significantly enhanced the separation process, and the removal efficiency has increased nearly twice. Moreover, the results showed that BTEX separation under pulsatile fluid flow was affected by the feed flow rate, extraction flow rate and the BTEX concentration as well.

Comparison between two Polyethersulfone concentrations in hollow fiber ultrafiltration membranes. Is it worth to use more polymer?

Polyethersulfone (PES) hollow fiber membranes were fabricated using dry-jet wet spinning technique, a phase inversion method, with 16 and 20% PES, N-methyl-2-pyrrolidone (NMP) as solvent and tap water as nonsolvent, in order to evaluate if the amount of polymer has a significant effect on its properties. They were characterized using SEM for a morphological analysis, a continuous system to measure pure water permeability (PWP) and molecular weight cutoff (MWCO), and a universal testing machine to tensile tests. The obtained results for PWP was an average of about 220 L m- ² h-1 bar-1 for the 16% PES membrane and 174 L m- ² h-1 bar-1 for the 20% PES membrane. The results of mechanical resistance and MWCO did not present statistical differences. Thus, it is confirmed that the 16% PES membrane can be as good as the 20%, despite using less polymer, a finding that can further motivate membrane modification studies and other related works.

Fouling scenarios in hollow fiber membranes during mini-plant filtration tests and correlation to microalgae-loaded feed characteristics

• Special algorithm for modelling fouling mechanisms over multiple filtration cycles. • Cake filtration contribution into fouling reversibility influenced by AOMs composition. • Algae cell conformation and size influence intermediate blocking mechanism nature. • Hydrophobic carbon increase adhesion of retained substances and exacerbate fouling. • Low molecular weight AOM substances contribute into combined fouling phenomenon. Fouling mechanisms inside polyethersulfone hollow fiber membranes during mini-plant filtration tests using microalgae-loaded feed water were modeled. Multiple filtration cycles tests were conducted in dead-end mode at conditions analogous to full-scale operation conditions using four microalgae species, individually employed in intact and lysed conditions, without prior separation of algae cells, cell debris and algal organic matter (AOM). Fouling mechanisms contributions, fouling rates and fouling resistances per one cycle were statistically quantified employing classical pore blocking filtration and resistance-in-series models via special algorithm. The results were reliably correlated to main microalgae feeds characteristics (i.e., AOM composition, average size distribution, conformation), retention of AOM substances, besides morphology and nature of the formed fouling layers. Standard blocking and intermediate blocking mechanisms resulted rather in irreversible fouling. Nature of intermediate fouling mechanism was interestingly altered based on microalgae characteristics, and consequently, influencing fouling reversibility and overall membrane performance. Helical microalgae cells tended to block membrane pores causing strong fouling, while rectangular and cylindrical microalgae cells showed a combined fouling phenomenon (competitive blocking of membrane pores and fouling layer voids). Moreover, cake filtration mechanism rather contributed into better fouling reversibility; however, for microalgae feeds having high hydrophobic organic carbon and biopolymers contents, strong irreversible fouling was revealed, irrespective of cake filtration mechanism contribution.

Self-assembly of defect-free polymer-based zeolite imidazolate framework composite membranes with metal-phenolic networks for high efficient H2/CH4 separation

In this study, defect-free metal organic framework membrane was first constructed on metal-phenolic networks (MPN) modified hollow fibers by competitive coordination based in-situ solvothermal crystallization. The activated MPN offered massive heterogeneous nucleation sites, facilitating the rapid synthesis of continuous and defect-free MOF membrane. Since different electrostatic environments of MPN may influence the growth rate of ZIF-8 nuclei on MPN, the thickness of MOF layer can be controlled by simply adjusting the preparation process of MPN. The coordination-driven cross-linking rather than tedious oxidative coupling reaction by tannin displayed higher kinetic rate, thereby effectively cut down the operation time of coating procedure to as fast as 10 s. Various techniques such as SEM, FTIR, XPS, XRD and EDS were applied to analyze the structure and morphology of MPN and MOF membranes, and gases separation experiments were applied to investigate the behavior of polymer-based MOF composite membranes. High performance continuous and dense ZIF-8/polyethersulfone hollow fiber membranes were successfully synthesized, which exhibited H2 permeance as large as 3.3 × 10−7 mol m−2 s−1 Pa−1 with very competitive ideal selectivity of 35.1 for H2/CH4.

Zeolitic imidazolate framework-67/carboxylated graphene oxide nanosheets incorporated polyethersulfone hollow fiber membranes for removal of toxic heavy metals from contaminated water

The removal of toxic heavy metals (e.g., copper and lead), owing to their hazardous effects on the human body, from water sources using membrane technology has been an attractive research area in recent years. In the present study, a novel nanohybrid comprising of zeolitic imidazolate framework-67 nanoparticles-decorated carboxylated graphene oxide nanosheets (ZIF-67/cGO) was synthesized and incorporated in polyethersulfone (P) hollow fiber membranes (HFMs) to enhance their separation performance. It was found that the presence of ZIF-67/cGO nanohybrid in HFMs positively altered the physicochemical properties of the resulting nanocomposite (ZcGP) HFMs, which helped them in achieving remarkably high pure water flux (346.4 ± 11.2 L/m2/h) and excellent flux recovery (95.7%). The adsorption capacity of these HFMs was 66.4 ± 3.2 mg/g for Cu2+ and 86.4 ± 4.3 mg/g for Pb2+. Moreover, significantly high removal of heavy metal ions (94.5 ± 1.2% for Cu2+ and 97.8 ± 1.1% for Pb2+) from the contaminated water was measured. The nanocomposite HFMs were easily regenerated to reuse them for 5 filtration cycles. Therefore, with these results, this study presented a novel membrane material for the efficient separation of heavy metals from the contaminated water sources.