PSF Membrane Research Articles

Ni-Zn metal-organic framework based membranes for rejection of Pb(II) ions

The present paper describes a sustainable and affordable supply of clean, and safe water approach to investigate Ni-Zn MOF embedded membrane for rejection of Pb (II) ions in aqueous solution. Ni-Zn MOF powder was prepared by solvo-thermal method, and then the Ni-Zn MOF embedded membranes with various concentrations (0.025 wt%, 0.05 wt% and 0.1 wt%). The membranes were fabricated by a common phase inversion method. Phase solutions of Pb(II) prepared with PVP at different concentrations in aqueous solutions. Water filtration and Pb (II) rejection tests were operated on a batch scale. The prepared Ni-Zn MOF powder characterized by FTIR, SEM-EDX analyses and zeta potential measurements. Ni-Zn MOF membranes were characterized by FTIR, SEM-EDX analysis, contact angle, and water permeability measurements. The effects of important parameters on adsorption including concentration and pH were investigated. The obtained results indicated that the maximum rejection of Pb(II) was 98% for a feed solution containing 80 mg Pb/L at pH 8 and assistance with 2 % PVP for 0.05 wt% Ni-Zn MOF membrane. Additionally, it was detected that blend membranes revealed better Pb(II) rejection than pure PSF membrane.

Reed Rhizome Residue-Based Activated Carbon Adsorption Ultrafiltration Membranes for Enhanced MB Removal.

Novel adsorption ultrafiltration (ADUF) membrane was designed for the removal of methylene blue (MB) by introducing Chinese herbal waste-based activated carbon (AC) into the ultrafiltration membrane. We prepared AC particles from Chinese herbal medicine waste residue (reed rhizome residue) as a raw material by ZnCl2 activation and introduced them into the ultrafiltration membrane by phase inversion to prepare a reed rhizome residue-based activated carbon adsorption ultrafiltration (RAC-ADUF) membrane. The RAC-ADUF-0.1 membrane was characterized by a series of physical structures and chemical properties, which showed that the prepared membrane has a more hydrophilic surface and high porosity. The RAC-ADUF-0.1 membrane showed an excellent pure water flux of 255.77 L·m-2·h-1 and a high bovine serum albumin rejection of 99.3%. The RAC-ADUF membranes also possessed excellent antifouling performance. Notably, the RAC-ADUF-0.1 membrane provides excellent removal of MB (99% retention) compared to conventional ultrafiltration membranes. The static adsorption capacity was up to 238.48 mg/g. The significant increase in dynamic adsorption capacity on the RAC-ADUF membrane is due to the three-dimensional distribution of RAC particles on the PSF membrane cross section, which provides more active sites and increases the contact time between RAC and MB. By fitting the adsorption kinetics and isothermal adsorption curves, the results showed that the pseudo-second-order kinetic model and the Langmuir isothermal model were more accurate in explaining the adsorption process. Further kinetic analysis showed that the adsorption process of MB molecules on RAC-ADUF membranes is controlled by both external mass transfer and intraparticle diffusion, with intraparticle diffusion playing a dominant role. In addition, the RAC-ADUF membrane exhibited outstanding adsorption and regeneration abilities, and the MB removal rate stayed at about 95% after 8 adsorption regeneration experiments. In conclusion, this study provides a new idea for the preparation strategy of an adsorption ultrafiltration membrane with high rejection and high permeability and the reuse of Chinese herbal medicine waste residue.

Evaluation of a Nanohybrid Membrane (PSF/ZnO) Efficiency in Natural Organic Matter Removal From Water

Background: Natural organic matter (NOM) in drinking water sources has always been regarded as a precursor for the formation of trihalomethanes (THMs), haloacetic acids (HAAs), and carcinogenic properties. This study aimed to fabricate and characterize a nanohybrid ultrafiltration membrane (PSF/ZnO) to evaluate its efficiency in NOM removal from water. Methods: Nanohybrid membranes with ratios of 0, 1, 2, 3 and 4% w/w of ZnO nanoparticles (NPs) were fabricated using the phase inversion method and characterized by the contact angle, AFM, FTIR, and SEM analyses. In this study, the effects of initial humic acid (HA) concentration, operating pressure, pH, and filtration time were examined on the HA removal efficiency and pure water flux through the membrane. Results: The results showed that addition of the ZnO NPs to the PSF membrane reduced the contact angle on the PSF/ZnO nanohybrid membrane’s surface. According to FE-SEM images, increasing the ZnO concentration changed the porous structure of the membranes from a spongy, teardrop shape to a finger-like channel structure. The FTIR analysis revealed an increase in the hydrophilicity of the membrane due to the presence of hydroxyl functional groups in ZnO. AFM images indicated an increase in the surface roughness of nanoparticle-containing membranes. It was found that an increase in the concentration of the ZnO NPs (0-4% w/w) increased HA removal efficiency (43.63-83.4%). Conclusion: This study demonstrated that the use of the PSF/ZnO nanohybrid membranes increased HA removal efficiency and pure water flux passing through the membrane.

Q-switched fiber laser using a polysulfone membrane enhanced with biosynthesized zinc oxide and titanium dioxide nanoparticles for use as saturable absorber

We presented the polysulfone membrane enhanced with zinc oxide and titanium dioxide (Psf membrane ZnO TiO2) saturable absorber (SA) to induce passively Q-switched erbium-doped fiber laser (EDFL). The Psf membrane ZnO TiO2 was synthesized by the phase inversion technique. To obtain the Psf membrane ZnO TiO2 as a SA, the SA was deposited on the fiber ferrule through a simple exfoliation technique. The modulation depth of the Psf membrane ZnO TiO2 SA was 1.06%, with a saturation intensity of 0.0006 MW cm−2. Stable Q-switched pulses were generated at 1572 nm with a threshold pump power of 59.80 mW after inserting the prepared Psf membrane ZnO TiO2 into the EDFL ring cavity. As the pump power ranges from 59.80 mW to 165.50 mW, the repetition rate increases from 13.05 to 22.61 kHz, while the pulse duration decreases from 76.60 to 44.23 µs. When the pump power reaches a maximum power of 165.50 mW, the corresponding pulse energy and optical signal-to-noise ratio are 19.00 nJ and 61.27 dB, respectively. To our best knowledge, this is the first research utilizing Psf membrane ZnO TiO2 as SA to generate Q-switched pulses. Our research work addresses a new reference for the generation of pulsed laser using Psf membrane ZnO TiO2 and discovers that it has numerous applications in nonlinear optics and ultrafast laser technology, which significantly broadens the barrier of materials for the ultrafast laser techniques.

Modification of Thin Film Composite Pressure Retarded Osmosis Membrane by Polyethylene Glycol with Different Molecular Weights.

An investigation of the effect of the molecular weight of polyethylene glycol (PEG) on thin-film composite (TFC) flat sheet polysulfone membrane performance was conducted systematically, for application in forward osmosis (FO) and pressure retarded osmosis (PRO). The TFC flat sheet PSf-modified membranes were prepared via a non-solvent phase-separation technique by introducing PEGs of different molecular weights into the dope solution. The TFC flat sheet PSf-PEG membranes were characterized by SEM, FTIR and AFM. The PSf membrane modified with PEG 600 was found to have the optimum composition. Under FO mode, this modified membrane had a water permeability of 12.30 Lm−2h−1 and a power density of 2.22 Wm−2, under a pressure of 8 bar in PRO mode, using 1 M NaCl and deionized water as the draw and feed solutions, respectively. The high water permeability and good mechanical stability of the modified TFC flat sheet PSF-PEG membrane in this study suggests that this membrane has great potential in future osmotically powered generation systems.

A novel loose nanofiltration membrane with superior anti-biofouling performance prepared from zwitterion-grafted chitosan

BackgroundDeveloping a novel loose NF membrane with zero NaCl rejection as well as effective anti-adhesive and anti-bacterial properties is significant for recycling and purification applications in many industries. Materials and methodA novel anti-biofouling loose nanofiltration (NF) membrane was fabricated by crosslinking a graft copolymer chitosan-g-poly(sulfobetaine methacrylate) (CS-g-PSBMA) as selective layer of a thin film composite (TFC) membrane for dye/salt separation. Specifically, CS-g-PSBMA was synthesized using cerium (IV) ion as the oxidant to initiate the graft polymerization of SBMA from CS. The PSF membrane was pre-wetted with hyperbranched polyethylenimine solution, then the loose NF membrane was fabricated by crosslinking CS-g-PSBMA with glutaraldehyde on the polysulfone (PSf) ultrafiltration membrane as the support layer. Results and discussionUpon optimization, the membranes show minimal rejection rates to NaCl or MgCl2, which is less than 5% but high rejection to dye molecules. After maintaining the pressure for 6 h, the interception rate for Congo red/mixed salts remained at 98% and that for methyl green/mixed salts was 80%. Further, experiment results show that the stable anti-bacterial rates of loose NF membrane against Escherichia coli and Staphylococcus aureus reached 98.3% and 99.0%, respectively.

Investigating the role of copper and zinc oxide nanomaterials in abatement of biofouling of ultrafiltration membrane in dynamic conditions

AbstractIn the present work, we demonstrate the synthesis, characterization, and biofouling study of polysulfone‐based mixed matrix membranes prepared with hydrophilic CuO and ZnO nanomaterial as antibacterial agents. Permeate flux was increased to 462.2 LMH for PSf/CuO (0.1%) and 472.5 LMH for PSf/ZnO (1.0%) from 191.2 LMH for pure PSf and BSA rejections were enhanced (from 70.91% to 95.73% for PSf/CuO (0.1%), from 70.91% to 93.47% for PSf/ZnO (1.0%). Biofilm growth over the modified membrane (was very less significant as correlated by lower pressure drop compared to pure polysulfone membrane in membrane fouling simulator (MFS) for 48 h. Adhesions of the Escherichia coli bacteria over the membrane surface were analyzed through an alcian blue test followed by a scanning electron micrograph. It was seen that the modified membrane showed a significant anti‐biofouling property with less adherence of alcian blue dye on the membrane surface and scanning electron micrographs demonstrated significantly lower biofouling. Mechanical strength of modified membrane increased up to 62.55 MPa for PSf/CuO (2%) and 55.41 MPa for PSf/ZnO (2%) as compared to 16.41 MPa of PSf membrane.

New Understanding of the Difference in Filtration Performance between Anatase and Rutile TiO2 Nanoparticles through Blending into Ultrafiltration PSF Membranes

The blending of nanomaterials into a polymeric matrix is a method known for its ability, under certain circumstances, to lead to an improvement in membrane properties. TiO2 nanoparticles have been used in membrane research for the last 20 years and have continuously shown promise in this field of research. Polysulfone (PSf) membranes were obtained through the phase inversion method, with different TiO2 nanoparticle concentrations (0, 0.1, 0.5, and 1 wt.%) and two types of TiO2 crystalline structure (anatase and rutile), via the addition of commercially available nanopowders. Research showed improvement in all studied properties. In particular, the 0.5 wt.% TiO2 rutile membrane recorded an increase in permeability of 139.7% compared to the control membrane. In terms of overall performance, the best nanocomposite membrane demonstrated a performance index increase of 71.1% compared with the control membrane.

Engineering of Ag-nanoparticle-encapsulated intermediate layer by tannic acid-inspired chemistry towards thin film nanocomposite membranes of superior antibiofouling property

Biofouling severely limits the application of reverse osmosis (RO) for water treatment. In this work, a green surface in-situ reduction method based on the tannic acid-inspired chemistry was used to introduce silver nanoparticles (AgNPs) into the intermediate layer of a thin film nanocomposite (TFN) membrane, as effectively improved the anti-biofouling performance of the membrane without sacrificing its desalination performance. SEM, EDX, AFM, XPS, DSA, ATR-FTIR and zeta potential were used to characterize the membranes. The plate counting method and confocal laser scanning microscopy (CLSM) were used to evaluate the anti-biofouling performance. And the long-term Ag+ release rate was measured using ICP-MS. Compared with unmodified thin film composite (TFC) membranes, the permeation flux of TFN membrane is improved while retaining the salt rejection. By optimizing the soaking time of FeCl3 and AgNO3 on the PSF membrane surface during the preparation of the intermediate layer and the M-phenylenediamine (MPD) and trimesoyl chloride (TMC) concentration for the interfacial polymerization. A water flux of 34.5 ± 1.2 L/m2 h and a salt retention of 98.0 ± 0.3% were achieved under the operating pressure of 1.55 MPa and 25 °C, for a 2000 ppm NaCl solution. The killing rates of the membrane to E. coli and S. aureus are almost 100% for a 24 h and 48 h contacting time. The number of bacteria attached to the membrane surface is far less than that of the unmodified membrane. More importantly, the Ag+ release rate was stable and controllable, allowing for long-term antibacterial properties.

Original Installation for Researching the Process of Forming Polysulfone Hollow Fiber Membranes

In this work an original installation (manipulator) has been created that allows one to obtain up to 30 samples of hollow fiber membranes in one molding cycle, while simultaneously varying the molding conditions in a wide range (polymer concentration, nature of solvent and precipitant, exposure time in air and in a precipitant environment, post-processing and washing modes samples, diameter of the carrier needle). This installation makes it possible to move to a fundamentally higher level of accumulation of experimental data on the relationship "the composition of the spinning solution - the structure of the hollow fiber membrane - the separating properties of the membrane." It will also make it possible to involve in these studies new laboratory samples of polymers whose synthesis volumes are insufficient for the existing methods of obtaining laboratory samples of hollow fiber membranes. The principle of operation of the manipulator was worked out when obtaining mini-samples of hollow fiber PSF membranes from 24 wt. % PSF solution in NMP with the addition of 19 wt. % PEG-400 blowing agent on a carrier needle with external deposition. Mini-samples were obtained for studies of morphology, mechanical, transport and separation properties in one molding cycle of the manipulator. The properties of mini-samples of hollow fiber PSF membrane were compared with the properties of a membrane made by the method of “dry-wet” molding with internal deposition from a solution of the same composition. It was found that the porous structures of the membranes differ significantly from each other. In a hollow fiber PSF membrane obtained on a manipulator, the porous structure was spongy with separate macrovoids of various shapes. However, in the membrane obtained by the “dry-wet” method, a dense selective layer was formed on the inner side of the backing layer of elongated finger-shaped pores. It is the formation of spongy pores along the entire perimeter of the fiber wall that led to a decrease in the permeability of the hollow fiber PSF membrane obtained on the manipulator. Thus, not only the composition of the solution, but also the molding method makes a significant contribution to the properties of the membrane.

Fabrication and Characterization of GO-Fe3O4/PSF Membrane with Phase Inversion Method

Polysulfones are hydrophobic which can reduce membrane permeability. Permeability can be increased through the application of hydrophilic materials such as GO-Fe3O4 to the polysulfone membrane so that the membrane is hydrophilic. The riset purpose to determine the effect of the percentage weight of different material compositions on the hydrophilicity properties of the polysulfone membrane. Membrane fabrication is carried out using the phase inversion method where the polymer solution is molded in a place and immersed in a coagulation bath containing non-solvent. This solvent exchange causes the polymer to form a solid matrix and become a membrane. The results showed that GO particles were successfully doped with Fe3O4 material shown by XRD analysis at a peak of 35.61˚ with a magnetite phase, while FTIR analysis showed that there was an absorption band characteristic of Fe-O streching vibrations. The results of the contact angle test on the GO-Fe3O4/PSF membrane 0.75 wt per cent were around 73.17˚ which showed the smallest hydrophobic value and the membrane surface morphology had an average pore size of 333.61 nm so that the addition of GO-Fe3O4 composites could increase membrane hydrophilicity.

ENHANCING HYDROPHILICITY OF POLYSULFONE MEMBRANE SURFACE BY UV IRRADIATION OF DIFFERENT WAVELENGTHS AND BY PEG GRAFTING

Polysulfone polymer (PSF) membrane has disadvantages due to its hydrophobicity, which may cause fouling and reduce separation performance. Therefore, this study aimed to enhance the hydrophilicity of PSF membranes by using irradiation at different ultraviolet (UV) wavelengths, followed by Poly(ethylene glycol) (PEG) grafting on the PSF surfaces. The hydrophilicity of the treated membrane surfaces was examined by measuring water contact angle (WCA), surface energy (SE), surface morphology, functional groups, salt rejection, and water flux in a filtration instrument. The results show that with long UV treatment for up to 72 h, the 312 nm wavelength gave lesser WCA than treatment at 254 nm. The treated PSF membrane irradiated at 312 nm for 72 h, followed by PEG grafting, was effectively improved and retained increased hydrophilicity for up to thirty days.

Effect of Silica Sodalite Functionalization and PVA Coating on Performance of Sodalite Infused PSF Membrane during Treatment of Acid Mine Drainage.

In this study, silica sodalite (SSOD) nanoparticles were synthesized by topotactic conversion and functionalized using HNO3/H2SO4 (1:3). The SSOD and functionalized SSOD (fSSOD) nanoparticles were infused into a Polysulfone (Psf) membrane to produce mixed matrix membranes. The membranes were fabricated via the phase inversion method. The membranes and the nanoparticles were characterized using Scanning Electron Microscopy (SEM) to check the morphology of the nanoparticles and the membranes and Fourier Transform Infrared to check the surface chemistry of the nanoparticles and the membranes. Thermal stability of the nanoparticles and the membranes was evaluated using Themogravimetry analysis (TGA) and the degree of hydrophilicity of the membranes was checked via contact angle measurements. The mechanical strength of the membranes and their surface nature (roughness) were checked using a nanotensile instrument and Atomic Force Microscopy (AFM), respectively. The textural property of the nanoparticles were checked by conducting N2 physisorption experiments on the nanoparticles at 77 K. AMD-treatment performance of the fabricated membranes was evaluated in a dead-end filtration cell using a synthetic acid mine drainage (AMD) solution prepared by dissolving a known amount of MgCl2, MnCl2·4H2O, Na2SO4, Al(NO3)3, Fe(NO3)3·9H2O, and Ca2OH2 in deionized water. Results from the N2 physisorption experiments on the nanoparticles at 77 K showed a reduction in surface area and increase in pore diameter of the nanoparticles after functionalization. Performance of the membranes during AMD treatment shows that, at 4 bar, a 10% fSSOD/Psf membrane displayed improved heavy metal rejection >50% for all heavy metals considered, expect the SSOD-loaded membrane that showed a rejection <13% (except for Al3+ 89%). In addition, coating the membranes with a PVA layer improved the antifouling property of the membranes. The effects of multiple PVA coating and behaviour of the membranes during real AMD are not reported in this study, these should be investigated in a future study. Therefore, the newly developed functionalized SSOD infused Psf membranes could find applications in the treatment of AMD or for the removal of heavy metals from wastewater.

Fabrication of Manganese Oxide-silica Based Functional Polymer Composite Membranes and Their Environmental Application

ABSTRACT Oil-water emulsion separation is a complicated task and recently oil-water spills made it crucial to find a solution to resolve this unfavorable environmental concern. Membrane separation is economical, environmentally safe, and operationally feasible separation process among different methods adopted so far. Keeping this in view neat polysulfone and manganese oxide silica composite membrane were synthesized. The prepared Mn3O4, mesoporous silica, Mn3O4@SiO2, neat and fabricated PSF membranes were thoroughly characterized by X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric, and differential scanning calorimetry, tunneling electron microscopy and scanning electron microscopy. The solvent content, porosity, surface behavior, thermal, and mechanical properties of the membranes were also studied. The increase in the concentration of nanofiller increases the solvent interaction, porosity, thermal stability, and mechanical strength. Amongst all 5 wt.% composite membrane have greater oil/water separation capacity due to greater amount of nanofiller and high porosity. Facile tuning of properties during fabrication process makes these composite membranes a potential candidate to address the oil/water pollution problem of important environmental concern.

In-situ Cu-doped carbon-supported catalysts applied for high-salinity polycarbonate plant wastewater treatment and a coupling application

• Cu and N doped biochar (Cu@NBC) was fabricated from the waste adsorbent. • The Cu@NBC/PDS system equipped with resistance to anions in high-salinity wastewater. • Cu@NBC can be uniformly deposited onto the PSF membrane. • Cu@NBC/PSF membrane exhibited instantaneous catalytic performance. • Electron-transfer process can inactivate bacteria to relieve membrane fouling. Organic pollutants decomposition in high-salinity wastewater is still a challenge for environmental restoration due to the inhibitory effects results from the consumption of radicals by anions. Herein, we demonstrated a non-radical oxidation process via the peroxydisulfate (PDS) activation rather than photocatalysis by the Cu 2+ adsorbed adsorbent-based nitrogen doped biochar (Cu@NBC) for efficiently decontaminating polycarbonate plant wastewater (PCW). After the pyrolysis, the Cu 2+ in the waste biosorbent were reduced to Cu 2 O, and the N-doping improved the fixation of Cu and the formation of Cu 2 O. Through both dynamic fitting and characterization analysis, the critical role of Cu 2 O in PDS activation rather than photocatalysis was revealed for the first time. Different from always reported 1 O 2 dominated non-radical process, an electron-transfer mechanism involving surface metastable species was proved to play a key role in the Cu@NBC/PDS system. Benefit from the electron-transfer process, the Cu@NBC/PDS system equipped with high resistance to the anions in high-salinity wastewater. The results indicated that BPA as well as chemical oxygen demand (COD) could be effective removal within 90 min. We further deposited the activator on an ultrafiltration membrane and exhibited a rapid oxidation of BPA as the wastewater passed through the filter, and the composite membrane can effectively inactivate bacteria, which will provide a safety strategy for mitigation of membrane fouling.

Kinetics studies on free radical scavenging property of ceria in polysulfone–ceria radiation resistant mixed-matrix membrane

Abstract Cerium oxide (ceria) contains two stable states of cerium ions (Ce3+ and Ce4+). The presence of these two states and the ability to swap from one state to another (Ce3+ ↔ Ce4+) by scavenging the highly reactive oxygen species (ROS) generated from radiolysis of water, ensure the enhanced stability of polysulfone (Psf) membranes in the γ-radiation environment. In this study, the ROS scavenging ability of ceria was studied. Ceria nanoparticles were found to scavenge ROS like hydroxyl radicals and hydrogen peroxide (H2O2). The H2O2 scavenging is due to the peroxidase-like catalytic activity of ceria nanoparticles. The ROS scavenging is responsible for offering protection to the Psf host matrix and in turn the stability to the Psf-ceria mixed-matrix membranes (MMMs) in γ-radiation environment. Thus, presence of ceria nanoparticles provides an opportunity for utilizing Psf-ceria MMMs in ionizing radiation environment with increased life span, without compromise in the performance.

Intensifying separation and antifouling performance of PSf membrane incorporated by GO and ZnO nanoparticles for petroleum refinery wastewater treatment

The fouling formation on the membrane’s surface has limited the membrane-based separation in industrial activities such as wastewater reclamation and seawater desalination. The nanomaterials' incorporation has been developed to enhance membrane performance. In this study, the combination of graphene oxide (GO) and zinc oxide (ZnO) nanoparticles to PSf membrane to improve the membrane performances to treat the petroleum refinery wastewater (PRW) was performed. The SEM-EDX result shows the presence of both GO and ZnO nanoparticles on the membrane's surface. They also produced the porosity of 83.00 ± 1.18 % for PSf/GO/ZnO, which was higher than the neat PSf with 52.20 ± 0.28 %. The FTIR and XRD result has confirmed the presence of GO and ZnO in the membrane that caused the increment in hydrophilicity and mechanical strength. The addition of GO and ZnO nanoparticles has reduced the water contact angle from 80° to 52° and increased water uptake ability from 16 % to 75 % compared to the neat PSf. It has also resulted in the highest permeate flux and pollutant removal compared to the other membranes with a maximum permeate flux of 35.03 L.m−2.h−1 and a rejection value 70.21 ± 2.33 % for total dissolved solids (TDS) and 74.68 ± 0.88 % for chemical oxygen demand (COD). The fouling resistance evaluation showed the addition of GO and ZnO nanoparticles successfully reduced the resistance during filtration, indicating a reduction in fouling tendency on the membrane's surface. These phenomena are proven by the antifouling potential analysis at the addition of GO and ZnO nanoparticles was exhibited the highest flux recovery ratio up to 90.44 ± 1.22 %.

Biocompatible chicken bone extracted dahllite/hydroxyapatite/collagen filler based polysulfone membrane for dialysis.

In the current study, dahllite/hydroxyapatite/collagen filler extracted via calcination of wasted chicken bone was blended with PSf polymer to obtain highly biocompatible, and antifoulant hemodialysis membranes. FTIR and Raman spectroscopic analysis was done to obtain information about the bonding chemistry of the obtained filler. The intermolecular interaction that existed between dahllite/hydroxyapatite/collagen filler and pristine PSf was confirmed by Raman spectroscopic study. The PSf polymer exhibited a sponge-like structure owing to its high thickness and slow exchange with non-solvent in coagulation bath whilst the instantaneous de-mixing course produced finger-like capillaries in dahllite/hydroxyapatite/collagen filler based PSf membranes as exposed by SEM photographs. The presence of different wt. % of filler composition in the PSf matrix improved the mechanical strength as revealed by fatigue analysis. The hydrophilic character improved by 78% while leaching consistency adjusted to 0%-4%. Pure water permeation (PWP) flux improved by nine times. The pore profile improved with the addition of filler as revealed by hydrophilicity experiment, PWP flux, and SEM micrographs. Fouling evaluation results disclosed that filler based membranes showed 36% less adsorption of protein (BSA) solution together with more than 84% flux recovery ratio. The biocompatibility valuation analysis unveiled that membranes composed of filler showed extended prothrombin and thrombin coagulation times, reduced activation of fibrinogen mass, and less adhesion of plasma proteins in comparison with pristine PSf membrane. The adsorption capacity of fabricated membranes for urea and creatinine improved by 31% (in the case of urea) and 34% (in the case of creatinine) in contrast with pristine PSf membrane. The overall results showed that the M-3 membrane was optimized in terms of surface properties, protein adhesion, anticoagulation activity, and adsorption amount of urea and creatinine.

Synthesis and characterization of piperazine containing polyaspartimides blended polysulfone membranes for fuel cell applications

A new polyaspartimide was synthesized via a Michael addition reaction of an aromatic bismaleimide (BMI) with aminoethylpiperazine (AEP) at 1:1 molar ratio. IR and NMR spectral techniques were used for the characterization of the newly synthesized polyaspartimide (PAI). The copolymer, piperazine containing polyaspartimide, was then blended with polysulfone (Psf) at 3 and 6 wt % by dissolving in the solvent DMF. The blend membranes are studied for their water uptake, ion exchange capacity, swelling ratio, chemical stability, morphology, and proton conductivity. It is observed from morphological studies that the porous structure of polysulfone has been retained even after the incorporation of PAI. The percentage water uptake of membranes of different compositions reveals that the blending of copolymer PAI with polysulfone enhances the water uptake nature of the membrane. The chemical stability on membranes revealed that Psf/PAI-6% has a degradation of about 2.26% which is much lower than that of neat Psf membranes (3.43%), higher chemical stability. The neat Psf found to have an IEC value of 8.045 mmol/g and the IEC values increase with the addition of PAI. The highest value of IEC is obtained for the 6% PAI loaded Psf blend membrane with a value of 8.235 mmol/g. The study on the capacity of proton exchange has proved that the copolymer blend membrane is given higher proton conductivity to the extent of 4.09 × 10-4 S cm-1.

Facile synthesis and characterization of Zno-HNT additive for enhancement of polysulfone membrane for Oil-In-Water separation

In this study, a novel nanocomposite of Zinc Oxide-Halloysite Nanotubes (ZnO-HNT) has been synthesized and incorporated into polysulfone membrane for the purpose of oily wastewater separation and purification. ZnO-HNT nanocomposite was synthesized as additives that can improve the hydrophilicity as well as the oleophobicity of the membrane. The nanocomposite was incorporated into PSf membrane in three different loading of ZnO and HNT. The novel nanocomposite has been characterized for its morphological characteristics using SEM, TEM and its physicochemical properties were also analyzed by FTIR and XRD. The performance of the modified polysulfone membrane was studied in terms of hydrophilicity, oil rejection and antifouling properties. The FTIR spectra recorded significant –OH peak at 3200 to 3500 cm−1 which contributes to the improve hydrophilicity of the membrane. XRD analysis shown that there are significant peaks at 2θ that attributes to both ZnO and HNT in which the nanocomposite exhibited more intense peak at 56.7° denoting increased amount of hydroxide groups. Additionally, the modified PSf membrane with ZnO-HNT additives has shown improved oil contact angle of 165°, water contact angle of 48.6° and 99% total rejection for oily wastewater indicating the improve performance of PSf through incorporation of ZnO-HNT.