Polyethersulfone Performance Research Articles

Effects of Preparation Conditions on Performance of PES:PEG Flat Sheet Membrane for MG Dye Separation

This study deals with the morphology and performance properties of a novel thin flat sheet ultrafiltration membrane; Malachite Green (MG) dye filtration behavior was evaluated in the cross-flow filtration system. The prepared membranes included the incorporation of 16 wt. % of polyether sulfone (PES)/DMF and 5 wt.% of Polyethylene Glycol (PEG) via the phase inversion process. Adding PEG decreased the internal concentration polarization, improved the membrane hydrophilicity, changed pore morphologies, and enhanced membrane performance. The SEM and AFM tests were used to characterize the composition and structure of the membrane. With different casting conditions, the membrane shape changed. The effect of membrane thickness (100, 150, and 200) µm and coagulation bath properties temperature (15, 25, and 35) °C and composition DMF (10, 20, 30 %) in water on the fabricated membrane were investigated. To evaluate the membrane filtration performance, the fabricated membranes were applied in an ultrafiltration system to treat Malachite Green dye solution at a concentration of (10 ppm) as a model pollutant. Based on the obtained results, the ideal membrane parameters were150 µm in thickness, 35°C in temperature, and 10% in composition DMF; the removal efficiency was observed to be (94.5%, 93%, and 99.5%) while the permeate flux (45, 35 and 30) LMH, respectively.

Pore structure regulation and continuous preparation with VNIPS process of membranes for bioseparation

Ultrafiltration technology has found widespread application in bioprocessing, particularly in protein concentration and buffer exchange for downstream processes. The demand for this technology has spurred research efforts to develop excellent membrane structures with superior separation functionality. However, challenges persist in transitioning laboratory research to industrial-scale continuous production processes while simultaneously optimizing membrane structure and performance through a single fabrication method. Thus, there is an urgent need for pilot-scale membrane preparation to improve membrane morphology and separation efficiency while ensuring scalability. This study investigates a continuous membrane fabrication method, systematically exploring the influence of different additives and vapor-assisted nonsolvent induced phase separation (VNIPS) on the structure and performance of polyethersulfone (PES) membranes. Evaluations of PES membranes with distinct structures were performed, employing flux decline, resistance analysis, and alkali resistance tests to distinguish their performance and bioseparation capabilities. The results showed that good sponge-like pore structure was obtained by VNIPS process, which realized the synergistic optimization of permeation and retention properties. Besides, the sponge-like porous structure membranes prepared by amphiphilic copolymer additives are more suitable for bioseparation.

Unveiling the relationship between MOF porosity, particle size, and polyethersulfone membranes properties for efficient decontamination of dye and organic matter

This work investigates the impact of reaction time on the textural properties and nanoparticles growth of metal organic framework (MOF) obtained from zinc substrate and their subsequent impact on the performance of polyether-sulfone (PES) ultrafiltration membranes. The MOF nanoparticles were synthesized at various reaction times between 2 and 8 h and then immersed in ascorbic acid to improve their hydrophilicity. A decline in the particle size with significant rise in the textural properties was noticed by decreasing the reaction time. Moreover, shifting of oxygen functional groups (–OH and C–O) was obtained after acid treatment. Next, 1.5 wt% of the acid treated MOFs were blended in the PES polymer for the formation of the hybrid membranes. The porosity, contact angle, water flux, surface morphology, and roughness were characterized for the resulting membranes. Moreover, the hybrid membranes were tested against the rejection of Eriochrome Black-T (EBT) and Humic acid (HA) pollutants. The characterization outcomes illustrated an incremental rise in hydrophilicity, porosity, and surface roughness of the hybrid membranes by decreasing the reaction time of the MOF nanoparticles. The water flux steadily improved by decreasing the reaction time of the MOFs. The maximum flux was 427.7 L m−2h−1 which was 2.2 times higher than the flux of the bare membrane. The elimination of EBT and HA, flux recover ratio and fouling resistance of both pollutants were improved by decreasing the particle size of MOFs. Overall, this study discloses that tuning the reaction time of MOF significantly influence the effectiveness of PES membranes in water treatment systems.

Removal of heavy metals and dye from water and wastewater using nanofiltration membranes of polyethersulfone modified with functionalized iron-silica nanoparticles

ABSTRACT In this study, the performance of polyethersulfone (PES) membranes, fabricated by modifying the iron nano-particles (M-Fe3O4), was investigated to remove heavy metals (HM) and Direct red 16 (DR16) dye from water. In this new research work, amine groups were first fixed on nano-particles by modifying iron nano-particles using TEOS and APTES methods. In the next step, M-Fe3O4 was used in the structure of membranes, and their effect on surface properties, hydrophilicity (HD), pure water (PW) flux, roughness (Ra), water permeability and removal rate of copper ion (CI) and DR16 dye were investigated. Also, characterization methods such as X-ray powder diffraction (XRD), scanning force microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), and antifouling properties have been used to evaluate the synthetic membranes. Thus, the performance of composite membranes showed that the pure water (PW) flux of the membrane M-Fe3O4 increased 1.9 times compared to the pure membrane. Moreover, the anti-fouling tests showed that the mixed matrix membranes (MMM) with 0.1 wt% of M-Fe3O4 showed the best anti-fouling properties with a 90% recovery rate and 55.98% fouling resistance. On the other hand, results showed that 0.1 wt% composite membrane resulted in the removal of CIs 92% and dye 99%.

Promotional effect of ammonium chloride functionalization on the performance of polyethersulfone/chitosan composite-based ultrafiltration membrane

This study aims to determine the effect of ammonium chloride (NH4Cl) on the characteristics and performance of polyethersulfone (PES)/Chitosan (CS)-based ultrafiltration composite membranes. The PES membranes were synthesized using phase inversion technique in dimethylacetamide (DMAc) solvent. A mixture of chitosan solution (fixed concentration) and NH4Cl (concentration 100–400 ppm) with ratio 2:1 (v/v) were coated into the PES membrane. The synthesized membranes morphology and properties were characterized by FTIR, SEM, contact angle, mechanical properties, and porosity tests. The membrane performance parameters including water permeability, rejection, and antifouling properties were studied. Incorporation of NH4Cl modified the membrane morphology and improved membrane porosity (49.64–71.5 %). The decrease in the water contact angle (80.21° to 63.53°) has confirmed the improvement of membrane hydrophilicity. Moreover, improved mechanical properties (11–16 MPa) were observed due to NH4Cl addition. The incorporation of NH4Cl improved water flux and specific flux membranes in dead-end cell from 51.34 to 159.18 L/m2∙h and 22–26.53 L/m2∙h∙bar, respectively, and in the cross-flow cell from 82.38 to 182.53 L/m2∙h and from 16.47 to 36.51 L/m2∙h∙bar, respectively. The addition of NH4Cl into membrane remarkably improved the rejection of bovine serum albumine (75.90 %, to 96.79 %), methyl orange (47.18–89.29 %), and methylene blue (60.14–97.34 %) Composite membranes have good fouling resistance as indicated by an increase in the flux recovery ratio (53.58–70.67 %). It is inferred that the addition of NH4Cl improved the performance of PES/chitosan composite membranes in ultrafiltration.

Industrial wastewater treatment using PES UF membranes containing hydrophilic additives: Experimental and modeling of fouling mechanism

In order to acquire preferred structure and performance, the effects of different hydrophilic additives, including triethylene glycol (TEG), polyethylene glycol (PEG), polyvinylpyrrolidone ( PVP ) at various concentrations, and coagulation bath temperature (CBT) on the morphology and performance of polyethersulfone (PES) ultrafiltration (UF) membranes were studied. The PES membranes were fabricated via non-solvent induced phase separation (NIPS) technique, and their performances were measured in terms of pure water flux (PWF), the flux of synthetic oil/water (O/W) emulsion, and industrial oily and textile wastewater, and oil rejection. Additionally, the morphology and hydrophilicity of the membranes were characterized by the SEM and water contact angle (CA) tests, respectively. The results revealed that the morphology and structure of the PES membranes depend on the type and concentration of the additive in the casting solution, as PES/PVP membranes had a denser structure than the PES/TEG and PES/PEG membranes. Besides, increasing CBT from 25 °C to 45 °C leads to the formation of a membrane with higher porosity, larger pores, higher water permeability, and lower oil rejection. The membrane containing 5%wt of TEG showed the best separation performance for treating synthetic and industrial wastewaters. Moreover, modeling of the flux decline using Hermia’s model and second kind standard blocking indicated the gel layer formation is the dominant fouling mechanism of the UF process of the oily wastewaters. • Effect of hydrophilic additives on morphology of PES UF membrane was investigated. • Effect of different CBTs on microstructure and performance of PES membranes was examined. • Optimal membrane exhibited an appropriate performance for treating refinery and textile industrial wastewaters. • Hermia’s model was applied to ascertain the governing fouling mechanisms.

High salinity enhances the adsorption of 17α-ethinyl estradiol by polyethersulfone membrane: isotherm modelling and molecular simulation

The increasing occurrence of steroidal hormone micropollutant in the aquatic environment and their associated consequences have caused serious environmental concerns globally. Adsorptive removal of hormonal pollutants using polymeric membranes has been suggested but information on their performance in various environmental conditions is lacking. In this study, we examined the effect of salinity on the performance of polyethersulfone (PES) membrane to remove synthetic hormone 17α-ethinyl estradiol (EE2) from water. Our results show that an increase of salinity from 0 to 3% results in higher retention of EE2 onto PES membrane from 79.3 to 98.7%. The experimental results fit the Freundlich isotherm model better as compared to the Langmuir model. The Freundlich parameters n and Kf yielded the highest values at 3% salinity. The molecular simulation results suggest that a high salinity increases the binding energy between EE2 and PES membranes, promoting the PES-EE2 interaction through π–π interaction, hydrogen bonding and hydrophobic interaction. This study provides valuable information for improving design of specialised treatment facilities (in farming, pharmaceutical industries, etc.) to allow better removal of EE2 and other low-polar organic contaminants from water via a membrane-based sorption-elution method, and we recommend the inclusion of salinity as a factor in modelling the adsorption capacity of membranes to prevent the oversaturation of membrane and minimise the release of contaminants into the environment.

Significance of thermodynamics and rheological characteristics of dope solutions on the morphological evolution of polyethersulfone ultrafiltration membranes

AbstractHerein, the effect of solvent type and polymer concentration on the thermodynamic and viscoelastic properties, and performance of polyethersulfone (PES) ultrafiltration (UF) membranes are investigated. The morphology and mechanical properties of the membranes are examined too. Rheological measurements indicated that solidification and instantaneous demixing occurred fast for PES/N‐methyl‐2‐pyrrolidone (NMP) dope solution. This resulted in a dense skin layer with a finger‐like structure confirmed by the scanning electron microscopy images. In comparison, PES/dimethylformamide (DMF) exhibited a delayed solidification and demixing with a sponge‐like structure. Rheological characteristics and ternary phase diagrams of two systems are examined to gain insights and make correlations with the morphology of resultant membranes. Performance analysis revealed that membranes derived from PES/NMP system exhibited both improved pure water flux and bovine serum albumin rejection suggesting the superiority of NMP compared to DMF as the solvent of choice for the preparation of PES UF membranes.

Removal of Dyes Using Graphene Oxide (GO) Mixed Matrix Membranes.

The application of membrane technology to remove pollutant dyes in industrial wastewater is a significant development today. The modification of membranes to improve their properties has been shown to improve the permeation flux and removal efficiency of the membrane. Therefore, in this work, graphene oxide nanoparticles (GO-NPs) were used to modify the polyethersulfone (PES) membrane and prepare mixed matrix membranes (MMMs). This research is dedicated to using two types of very toxic dyes (Acid Black and Rose Bengal) to study the effect of GO on PES performance. The performance and antifouling properties of the new modified membrane were studied using the following: FTIR, SEM, AFM, water permeation flux, dye removal and fouling, and by investigating the influence of GO-NPs on the structure. After adding 0.5 wt% of GO, the contact angle was the lowest (39.21°) and the permeable flux of the membrane was the highest. The performance of the ultrafiltration (UF) membrane displayed a rejection rate higher than 99% for both dyes. The membranes showed the highest antifouling property at a GO concentration of 0.5 wt%. The long-term operation of the membrane fabricated from 0.5 wt% GO using two dyes improved greatly over 26 d from 14 d for the control membrane, therefore higher flux can be preserved.

Pregelation of sulfonated polysulfone and water for tailoring the morphology and properties of polyethersulfone ultrafiltration membranes for dye/salt selective separation

Sulfonated polysulfone (SPSf) and water as additives were employed to tailor the morphology and performance of polyethersulfone (PES) ultrafiltration (UF) membrane using non-solvent induced phase separation (NIPS) for the purposes of dye and salt selective separation. Results showed that the viscosity of PES/SPSf/DMAc casting solution (polymer concentration 28 wt%) sharply increased from 1900 to 2650 mPa s with the addition of H2O (7 wt%) owning to the formation of pregelation. It was also revealed that PES polymer chains solidified and shrank faster than SPSf polymer chains during NIPS process, leading to –SO3- groups of SPSf to cover the surface of PES/SPSf polymer matrix. The resultant PES/SPSf UF membrane possessed superior pure water permeance (110.4 L/m2 h bar) compared with the pristine PES membrane (0.13 L/m2 h bar). The improvement in water permeance was ascribed to the synergy of SPSf and water, which enhanced the surface pore size, top surface porosity and hydrophilicity of PES membrane. Meanwhile, molecular dynamic (MD) simulations revealed that H2O can weaken the interaction between PES and SPSf chains and slow down the mutual diffusion in favour of the movement and ordered arrangement of chains. Additionally, the rejection of Evans blue (EB), Coomassie brilliant blue (BBR), Congo red (CR) and Acid fuchsin (AF) dye solution (0.1 g/L) by PES/SPSf membrane were 99.0%, 99.9%, 99.2% and 90.1%, respectively, whereas Na2SO4 rejection was less than 5%. In sum, this work supplies a simple avenue to tailor PES membrane with enhanced permeance as well as separation performance of dye/salt mixture.

Static and Dynamic Mechanical Performance of Carbon Fiber Reinforced Polyethersulfone Composites

This study has been carried out to demonstrate the effect of short carbon fiber (SCF) loading on static and dynamic mechanical performance of polyethersulfone (PES) composites. Different combinations of SCF/PES composites were prepared by extrusion followed by injection molding. The static mechanical properties such as hardness, tensile and flexural properties of PES based composites were analyzed following ISO standards. As engineering materials, the polymer composites with high modulus as well as excellent damping properties are of great interest in aerospace and automotive industries for severe dynamic environment. Furthermore, in addition to static properties of composites, dynamic mechanical behaviour of PES based composites was evaluated. Mechanical test results showed that increasing the SCF wt. % in the composites increases the hardness, tensile and flexural properties. Furthermore, the optimal SCF loading was found to be 30 wt. % for significantly improving the overall composite mechanical performance. Upon the reinforcing of SCFs, an improvement in the storage modulus was found. Based on the fractographic analysis, orientation and aligned structure of carbon fibers, good bonding of fibers within the matrix and better fiber-matrix interaction were the primary reasons leading to the improvement of mechanical properties. The optimized composite (PES with 30 wt. % of SCF) could be used in automotive components like frames, flap covers and gears of printing machinery.

Effect of cellulose nanocrystals on performance of polyethersulfone nanocomposite membranes using electrospinning technique

In this study, effects of cellulose nanocrystals (CNCs) as variable nano additive on the morphology and performance of polyethersulfone (PES) membranes were investigated. PES/CNC nanocomposite membranes were prepared using electrospinning technique. Various contents (0.1, 0.5, and 1.0 wt%) of the CNCs were employed to prepare PES/CNC membranes. The effects of CNCs on the membrane morphology and performance were monitored by fabrication of a control membrane without CNCs. The membranes were characterized using scanning electron microscopy, pure water flux (PWF), and surface hydrophilicity (by contact angle), bacteria removal and Brunauer‐Emmet‐Teller. In general, it was found that addition of CNCs led to smooth fibers with many interconnected voids and significant higher hydrophilicity, as well as higher PWF. Surface analysis of the membranes demonstrated that mean of the fibers diameters of the prepared membranes with CNCs in the PES solution are smaller compared with those of the membrane prepared with no CNCs. In addition, the diameter of fibers considerably influence pore size and the ability of membranes for PWF. PES/CNC0.5 membrane had the highest PWF of 2125 L/m2 h among the studied membranes. The contact angle measurements revealed that the hydrophilicity of PES/CNC membranes enhanced by increasing the CNC content. PWF of pure PES was 136 L/m2 h. Whereas with the addition of 0.1, 0.5, and 1.0 wt% CNCs content, the PWF increased to 148, 235, and 210 L/m2 h, respectively, indicating that the addition of CNCs can be a useful way to improve water flux. The synthesized membranes were used for the removal of bacteria, Escherichia coli, from the waste water. Bacterial removing efficiency reached to 62% by adding 0.5 wt% CNC into the PES. Finally, this study provides valuable insight into the preparation of high‐performance PES/CNC nanocomposite membranes. POLYM. COMPOS., 40:E835–E841, 2019. © 2018 Society of Plastics Engineers

Improvement in nano-hybrid membrane PES–nanosilica performance using ultra violet irradiation and acetone–ethanol immersion for produced water treatment

This research was performed primarily to investigate the effect of membrane immersion in hydrophilic solvents (mixture of acetone–ethanol). Special emphasis was focused on the study of membrane morphology toward performance of nano-hybrid polyethersulfone (PES)–nanosilica membrane for produced water treatment. In this research, nano-hybrid PES–nanosilica membranes with immersion and without immersion were prepared using dry-/wet-phase inversion technique. The prepared membranes were immersed in the mixture of acetone–ethanol at various mass ratios of 1:5 and 1:8. The immersion of membranes allowed the alteration of membrane morphology to be more hydrophilic. The scanning electron microscope (SEM) result and Fourier transform infra red spectroscopy analysis confirmed that membrane immersed in acetone–ethanol significantly enhanced the hydrophilicity of the membrane by increasing the number of hydrophilic-specific functional group. The SEM surface images indicated the good compatibility between the PES and nanosilica for immersed membrane. Nano-hybrid membrane immersed in the acetone–ethanol of 1:8 performed best as shown by the flux and rejection enhancement. Comparing to the pure PES performance, the permeate flux and rejection of nano-hybrid membrane PES–nanosilica increased to 5 and 39%, respectively. On the other hand, immersed nano-hybrid membrane in acetone–ethanol of 1:8 with combination of UV irradiation increased the permeate water flux and rejection to 21 and 15%, respectively. In addition, the immersion in the acetone–ethanol displayed better antifouling behavior. The research results revealed the improvement in membrane performance for produced water treatment after being immersed in acetone–ethanol and UV-irradiated.

Potential of DMSO as greener solvent for PES ultra‐ and nanofiltration membrane preparation

ABSTRACTIn this article, the performance of polyethersulfone (PES) ultra‐ and nanofiltration membranes, prepared with the non‐toxic solvent dimethyl sulfoxide (DMSO), was investigated. The membranes were prepared by immersion precipitation via phase inversion. Experimental results proved that DMSO is a better alternative to N‐methyl‐2‐pyrrolidone (NMP) as solvent for PES ultrafiltration membranes as the membranes had a higher permeability and rejection of bovine serum albumin (BSA). An explanation was found based on experimental cloud point data and scanning electron microscopy images showing the morphology. The rejection of BSA and rose Bengal (RB) was proportional to the polymer concentration. On the contrary, the permeability decreased with increasing polymer concentration. For a casting thickness of 250 µm, an optimal balance between permeability and rejection of macromolecules for ultrafiltration was found at 24 wt % PES. The permeability was inversely proportional to the casting thickness, but a small decrease in rejection was observed when lowering the thickness. A good balance between permeability and rejection of RB was found, using a reference nanofiltration membrane of 28.5 wt % PES with 150 µm casting thickness. This membrane achieved a RB rejection of 95.3% and a pure water flux of 2.03 L m−2 h−1 bar−1. The membrane thickness and polymer concentration did not have a clear influence on the hydrophilicity of the membranes. It can be concluded that DMSO is a benign alternative as compared to traditional solvents such as NMP and also results in better PES membrane performances. DMSO is a perfectly suitable solvent for ultrafiltration applications and has potential to be used for nanofiltration applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46494.

Enhancement of polyethersulfone (PES) membrane performance by modification with rice husk nanosilica for removal of organic matter in water

This paper reports the effects of rice husk nanosilica addition on the performance of polyethersulfone (PES) membrane. Polyethersulfone membrane (PES) was fabricated by using N-methyl-2-pyrolidone (NMP) as a solvent and rice husk nanosilica as a modifying agent. The influence of the rice husk nanosilica additive on the characteristics and performance of the membrane has been studied. Scanning Electron Microscopy (SEM) analysis confirmed that the manufactured membrane has an asymmetric morphological structure consisting of two layers. The upper part of the membrane is a thin layer, meanwhile in the bottom side is a porous layer. The addition of 5% nanosilica resulting a PES membrane to have a bigger porous than that of pristine PES. The pure water flux of nanosilica-modified membranes were greater in comparison to the pure water flux of unmodified PES membrane. The performance of all membranes were evaluated on humic acid removal. The highest selectivity was showcased by pure PES membrane. The introduction of rice husk nanosilica additive to the membrane declined the selectivity of the membrane to humic acid in the feed solution. This is caused by the pores enlargement and enhanced hydrophilicity of the membrane after modification with rice husk biosilica.

Effect of solvents on the morphology and performance of Polyethersulfone (PES) polymeric membranes material for CO2/CH4 separation

Membrane technology has several advantages such as the ability to separate chemical species within compact plant footprints, low thermal energy requirements and simple process flow schemes. By optimizing the available materials and analysis, this work comes with the objective to synthesize the polymeric membrane, which has the best separation performance. In this work, three (03) membranes have been synthesized and a comparative analysis were conducted based on different types of solvent namely N, N-dimethylacetamide (DMAc), N, N-dimethylformamide (DMF), N-methyl-2-pyrrolidinone (NMP). In characterizing the synthesized membrane, Thermo Gravimetric Analysis (TGA), Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis were used. A comparative study was carried out to compare the effects of each solvent towards CO2 separation performance.

Recent advances in hydrophilic modification and performance of polyethersulfone (PES) membrane via additive blending.

The blending of additives in the polyethersulfone (PES) matrix is an important approach in the membrane industry to reduce membrane hydrophobicity and improve the performance (flux, solute rejection, and reduction of fouling). Several (hydrophilic) modifications of the PES membrane have been developed. Given the importance of the hydrophilic modification methods for PES membranes and their applications, we decided to dedicate this review solely to this topic. The types of additives embedded into the PES matrix can be divided into two main categories: (i) polymers and (ii) inorganic nanoparticles (NPs). The introduced polymers include polyvinylpyrrolidone, chitosan, polyamide, polyethylene oxide, and polyethylene glycol. The introduced nanoparticles discussed include titanium, iron, aluminum, silver, zirconium, silica, magnesium based NPs, carbon, and halloysite nanotubes. In addition, the applications of hydrophilic PES membranes are also reviewed. Reviewing the research progress in the hydrophilic modification of PES membranes is necessary and imperative to provide more insights for their future development and perhaps to open the door to extend their applications to other more challenging areas.

Deep eutectic solvent as novel additive for PES membrane with improved performance

Abstract For the first time, deep eutectic solvent (DES) is used as an efficient pore-forming additive to tailor the morphology and performance of polyethersulfone (PES) ultrafiltration (UF) membrane. The ultrafiltration experiments indicated that the water flux of membrane was significantly increased while the rejection ratio of membrane slightly increased by adding suitable amounts of synthesized DES (decanoic acid: N4444-Cl (2:1)) into the casting solution. When the concentration of DES was 2 wt%, the water flux of the membrane reached a maximum value of 142.84 L/(m2·h), which was 4.65 times that of pure PES membrane. Meanwhile, the rejection ratios of pepsin, egg albumin and bovine serum albumin were as high as 91.5%, 97.3% and 99.0%, respectively. Moreover, the role of the DES in the formation process of PES membrane was investigated by viscosity measurement, scanning electron microscope (SEM), Fourier transform infrared spectra (FTIR), and thermogravimetric analyzer (TGA). It was concluded that component decanoic acid and component N4444-Cl in DES worked synergistically to improve membrane performance during the phase inversion process. Compared with other additives, the synthesized DES was a superior pore former. DES might provide new possibilities as the pore-forming agent for membrane formation.

Effect of gamma-ray irradiation at low doses on the performance of PES ultrafiltration membrane

The influence of gamma irradiation on the performance of polyether sulfone (PES) ultrafiltration (UF) membrane was investigated at low absorbed doses (0–75kGy) using a cobalt source. The performance of the UF membranes was tested using low level radioactive wastewater (LLRW) containing three types of surfactants (anionic, cationic and nonionic surfactants). The physical and chemical properties of membrane surface were analyzed, and relationships between these properties and separation performance and fouling characteristics were determined. At 10–75kGy irradiation, there were no significant changes observed in the membrane surface roughness or polymer functional groups, however the contact angle decreased sharply from 92° to ca. 70° at irradiation levels as low as 10kGy. When membranes were exposed to the surfactant-containing LLRW, the flux decreased more sharply for higher dosed irradiated membranes, while flux in virgin membranes increased during the filtration processes. The study highlights that fouling properties of membrane may be changed due to the changes of surface hydrophilicity at low dose irradiation, while other surface properties and retentions remain stable. Therefore, a membrane fouling test with real or simulated wastewater is recommended to fully evaluate the membrane irradiation resistance.

Development of a High Performance PES Ultrafiltration Hollow Fiber Membrane for Oily Wastewater Treatment Using Response Surface Methodology

This study attempts to optimize the spinning process used for fabricating hollow fiber membranes using the response surface methodology (RSM). The spinning factors considered for the experimental design are the dope extrusion rate (DER), air gap length (AGL), coagulation bath temperature (CBT), bore fluid ratio (BFR), and post-treatment time (PT) whilst the response investigated is rejection. The optimal spinning conditions promising the high rejection performance of polyethersulfone (PES) ultrafiltration hollow fiber membranes for oily wastewater treatment are at the dope extrusion rate of 2.13 cm3/min, air gap length of 0 cm, coagulation bath temperature of 30 °C, and bore fluid ratio (NMP/H2O) of 0.01/99.99 wt %. This study will ultimately enable the membrane fabricators to produce high-performance membranes that contribute towards the availability of a more sustainable water supply system.