Formation kinetics and characterization of polyphthalazinone ether ketone hollow fiber ultrafiltration membranes (original) (raw)
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Journal of Membrane Science
Polyethersulfone (PES) hollow fiber ultrafiltration (UF) membranes were fabricated using methanol, ethanol, n-propanol as well as water as additives and N-methyl-2-pyrrolidone (NMP) as a solvent. Asymmetric hollow fiber UF membranes were spun by wet and dry/wet phase inversion method from 18 wt.% solids of PES/non-solvent/NMP solutions. The non-solvents were methanol, ethanol, n-propanol and water while the external coagulant was water. Effects of non-solvent and ethanol concentrations in the dope solution and air-gap distance on morphology and separation performance of PES hollow fiber UF membranes were investigated. UF membranes were characterized in terms of their solubility parameter difference, pore size and pore density measurements, scanning electron microscope (SEM) while UF experiments were conducted using polyethylene glycol (PEG 10,000 M W) and two kinds of proteins, lysozyme (14,400 M W) and chicken egg albumin (CEA 45,000 M W) as a solute. It was found that the PES UF membrane morphology changed slowly from long and wide finger-like structure through a thin finger-like structure to the sponge-like structure with some voids as ethanol concentration in the dope solution increased from 0 to 25 wt.% using 90:10 NMP/H 2 O as a bore fluid; pure water permeation fluxes (PWP) increased from 47 to 167 L/(m 2 •h•bar) while rejections of PEG 10,000 and two protein for wet-spun PES hollow fiber membranes were increased within less than 10 wt.% ethanol concentration and then decreased with an increase of ethanol concentration. Experimental results illustrated that PWP flux and solute rejection of the dry/wet-spun fibers were higher than that of the wet-spun fibers when 15 wt.% ethanol and 15 wt.% methanol were used as additives. PWP flux of PES hollow fibers using 25 wt.% n-propanol and 7.5 wt.% water (dry/wet) as additives in the dope solution were higher while their rejections were lower. In addition, the pore sizes of internal surfaces of PES hollow fiber membranes were controlled by adjusting the ethanol or methanol concentration in the dope solution. Using above method, PES hollow fiber UF membrane with high PWP could be prepared while the molecular weight cutoff of PES hollow fiber membranes is approximately 10,000.
Microporous and Mesoporous Materials, 2017
Polyethersulfone (PES) ultrafiltration membrane with enhanced simultaneous permeability and fouling eresistance property was prepared using a new synthesized aromatic polyamide (PA-6) as an additive. A series of asymmetric membranes were prepared by adding different amounts of PA-6 to the casting solution using the phase inversion induced by immersion precipitation method. Attenuated total reflection-Fourier transform infrared spectra (ATR-FTIR) and water contact angle measurement confirmed the PA-6 enrichment at the membrane surface and increased the membrane hydrophilicity and wettability. The SEM images elucidated the effect of PA-6 addition on the PES membrane morphology by increasing the pore density. The results of filtration performance, which carried out by dead-end filtration of bovine serum albumin (BSA) solution showed that the permeability and fouling resistance property was improved by optimizing the PA-6 content. When the PA-6 content was 2 wt%, the permeability reached approximately 10 times over the pure PES membrane. In comparison to the blend membrane of PES and 2 wt% of polyvinyl pyrrolidone (PVP), the blend membrane of 2 wt% of PA-6 showed significant flux recovery ability. The rejection of all the blended membranes was approximately at high point over 95%. In addition, the results were compared with those obtained using PVP as a usual additive. Although the PVP blended membranes exhibited higher permeability, they showed lower antifouling properties. Finally, a membrane with 1 wt% PVP and 1 wt% PA-6 was prepared and showed the best performance regarding improved permeability and antifouling properties.
Preparation, characterization, and performance of a novel hollow fiber nanofiltration membrane
Polymers for Advanced Technologies, 2015
Two generations of aliphatic hyperbranched polyester (HBPE) were synthesized from 2,2-bis(methylol)propionic acid and 1,1,1-trihydroxymethyl propane (TMP) as the core moiety by melt condensation method and were blended with cellulose acetate to prepare asymmetric membrane using a phase inversion process. Characterization of the prepared membranes for thermal behavior and morphological studies also has been made using TGA, DSC and SEM techniques. Water contact angle, pure water flux, water content, hydraulic resistance and molecular weight cutoff determinations were applied in order to study of filtration properties and surface and bulk hydrophilicity of the membranes. (FTIR/ATR) and contact angle results proved existence of (HBPE) on the surface of modified membranes and (FE-SEM) images have good correlation with flux and MWCOs. The result shows that, the surface hydrophilicity of membranes incorporating HBPE is much higher than pure CA or even (PEG-600) modified CA membranes. Furthermore, results show CA-HBPE membranes have lower flux and MWCOs, higher hydraulic resistance and better thermal and mechanical properties in comparison to the membranes modified by linear pore-forming agent.
Journal of Applied Polymer Science, 2011
In our recent study, pH-sensitive polyethersulfone (PES) hollow fiber membranes were prepared by blending poly (acrylonitrile-co-acrylic acid) (PANAA), and the electroviscous effect had great effect on the water flux change. While the question remains: is the water flux change caused by the electroviscous effect for all the membranes with different pore sizes? Herein, pH-sensitive hollow fiber membranes with different pore sizes were prepared. The pore size and the theoretic water flux were calculated through the ultrafiltration of polyethylene glycol (PEG) solution. Comparing the calculated fluxes and the experimental ones, we found that the water flux change was mainly caused by the pore size change at the pH value larger than pKa, while that was caused by both the pore size change and the electroviscous effect when pH value was smaller than the pKa, and the pore size change was caused by the ionization of the ACOOH in the copolymer. V C 2011
A study on the performance and morphology of multicomponents hollow fiber ultrafiltration membrane
(Polysulfone/poly(vinylpyrolidone)-K30/N,N-dimethylacetamide) hollow fiber ultrafiltration membrane was spun using dry-wet spinning method. The membrane was produced at different shear rate. Permeation properties and separation tests were examined using pure water flux and sodium chloride solution of concentration 1g/L respectively. Membrane morphology and molecular orientation were observed and directly measured using scanning electron microscopy (SEM) and plan polarized infrared spectroscopy. Positive infrared dichroism was detected only in samples of highest shear membranes. This suggests that the polymer molecules become aligned under high shear. Permeation test using pure water showed that increasing shear rate increases flux. On contrary, percentage rejection using sodium chloride solution showed a decreasing trend in rejection with the increased in shear rate. Increasing shear rate during dope extrusion through spinneret in the spinning of hollow fiber ultrafiltration membranes will apparently decrease the skin layer thickness and thus increasing the flux and also enhances the molecular orientation in the skin layer which causes high percentage rejection which was in the range of 21% to 33% for transmembrane pressure of 6 bar. The results indicate that there is a strong correlation between extrusion shear rate and the membrane morphology thus affecting the flux and rejection of hollow fiber ultrafiltration membranes.
Preparation and characterization of ultrafiltration membranes for toxic removal from wastewater
Desalination, 2004
Membrane engineering is currently classified as an eco-friendly cleaning technology in various fields, especially for wastewater treatment, and its use is increasing due to the growing interest in water environment protection and preservation. In this study, a new approach to improving membrane performance is proposed by using polyethersulfone (PES) as a polymer blend with polyphenylsulfone (PPSU). PPSU-PES ultrafiltration membranes were prepared using the classical phase inversion method to remove dyes from simulated wastewater of the leather tanning industry. Four concentrations of PES were studied (i.e. 0, 4, 5, and 6 wt.%), while keeping the concentration of PPSU constant at 20%. A scanning electron microscope (SEM) and atomic force microscopy (AFM) were used to characterize the surface structure of the cross-section, top, and bottom membranes. It was found that the structural morphology of the membrane varied with the PES concentration. The addition of PES helped significantly decrease the contact angle and increase the porosity of the PPSU/ PES/N-methyl-2-pyrrolidinone (NMP) blend membranes by approximately 15.2% and 280%, respectively, and to decrease the thickness of the membrane compared with neat PPSU. The effects of black dye (i.e. acid black 210, MW ¼ 938.017 g mol À1) concentration (i.e. 35, 45, and 65 ppm), feed temperature, and pH on the permeate flux and dye removal were also investigated in this study. It was found that there is a minor effect of the feed temperature and no effect of pH on the permeation flux. Also, it was discovered that the performance of the membranes improved from 5.77 to 27.7 and 3.46 to 19.62 for distilled water and feed solution of 35 ppm, respectively over those prepared from the neat PPSU membrane, while the dye removal was higher than 99.65% for all of the membranes studied.
Development of polybenzimidazole ultrafiltration hollow-fiber membranes
DESALINATION AND WATER TREATMENT, 2021
Polybenzimidazole (PBI) ultrafiltration (UF) hollow-fiber membranes (HFMs) were fabricated using a continuous fiber-spinning line developed at SRI International. Based on the previously developed fabricating conditions for reverse osmosis (RO) and nanofiltration (NF) HFMs, UF HFMs with a large open pore size (50-100 nm) at the shell barrier layer were obtained by switching the dry-jet wet-spinning process to a complete wet-spinning process. To maximize the membrane permeability, bore solution compositions were formulated based on the previous composition, and 100% isopropanol was noticed leading to the largest open pore size on the lumen side. The flow rate ratio of solutions was adjusted during fiber spinning to reduce the fiber wall thickness and the optimized wall thickness, 95 µm was obtained to sustain a running at 20 psi when the flow rates of bore solution and dope solution were 0.35 and 0.9 mL/min, respectively. With the above optimal fabricating protocol, a PBI UF HFM with a pure water flux of 58 LMH at 20 psi was fabricated and its pore size was measured to be 21-25 nm by capillary flow porometry. The resulting UF HFMs showed a good anti-fouling performance in a series of filtration tests with humic acid, bentonite clay, and bovine serum albumin as foulants.
Preparation of sulfonated poly(phthalazinone ether sulfone ketone) composite nanofiltration membrane
Journal of Membrane Science, 2005
Thin film composite (TFC) membranes were prepared from sulfonated poly(phthalazinone ether sulfone ketone) (SPPESK) as a top layer coated onto poly(phthalazinone ether sulfone ketone) (PPESK) ultrafiltration (UF) support membranes. The effects of different preparation conditions such as the SPPESK concentration, organic additives, solvent, degree of substitution (DS) of SPPEK and curing treatment temperature and time on the membrane performance were studied. The SPPESK concentration in the coating solution was the dominant factor for the rejection and permeation flux. The TFC membranes prepared from glycerol as an organic additive show better performance then those prepared from other additives. The rejection increased and the flux decreased with increasing curing treatment temperatures. The salt rejections of the TFC nanofiltration (NF) membranes increased in the order MgCl 2 < MgSO 4 < NaCl < Na 2 SO 4 . TFC membranes showed high water flux at low pressure. SPPESK composite membranes rejections for a 1000 mg L −1 Na 2 SO 4 feed solution was 82%, and solution flux was 68 L m −2 h −1 at 0.25 MPa pressure.