Factors Affecting Mass Transport Properties of Poly(ε-caprolactone) Membranes for Tissue Engineering Bioreactors (original) (raw)
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Porosity and protein adsorption of four polymeric microfiltration membranes
Journal of Membrane Science, 1993
Four different microfiltration (MF) membranes were analysed with respect to porosity and protein adsorption. Liquid displacement porosity (LDP) and adsorption of "C-labelled /3-lactoglobulin were used as characterization methods. LDP showed a clear pore size distribution for all membranes analysed, with maximally 10% of the pores having at least 90% of the permeability. The protein adsorption came to equilibrium within 30 minutes, giving decreased permeabilities for all membranes. The permeability loss could not be modelled as a simple membrane pore restriction, but the protein load corresponded to a monolayer of protein adsorbed on and in the membranes.
Journal of Membrane Science, 2010
A systematic study investigating the effect of membrane material and morphology on the filtrationcycle based on performance of three microfiltration membranes employed for filtering feed solution of Bovine Serum Albumin with yeast suspension has been carried out in dead-end filtration mode. The effects of operating conditions, like feed solution pH, transmembrane pressure (TMP), and membrane cleaning methods have been studied to establish a possible relationship with membrane fouling and to reduce the fouling that occurs during filtration. It was found that filtration resistance increases for the selected membranes with an increase in pH of the feed solution. An increase in TMP increases the permeate flux; however, the effect is not linear due to cake compression at higher TMP. The performance based on the filtration cycle is evaluated, and potential cleaning solutions to restore the permeate flux of filtration after several filtration cycles are identified. Scanning electron microscopy images demonstrate the experimental findings. The expanded polytetrafluoroethylene membrane flushed with caustic soda solution is found to be the most suitable and efficient membrane for microfiltration without significant reduction in flux and protein transmission, even after several filtration cycles.
Influence of type and pore size of membranes on cross flow microfiltration of biological suspension
Journal of Membrane Science, 2011
ABSTRACT Pressure driven membrane processes have been substantially used for the separation of solids and liquid. The main disadvantage of such systems is rapid fouling, causing higher energy consumption and lower flux output. The main objective of this study was to explore the influences of type and pore size of membranes on bio-fouling by biological suspensions. Cellulose acetate, polyethersulfone, mixed ester, polycarbonate (CA, PES, ME, PC) membranes with three different pore sizes (0.40–0.45, 0.22, 0.10μm) were used in cross flow microfiltration experiments. The flux decline behavior was observed with time. Permeate samples were taken for protein and carbohydrate analysis. Surface roughness of clean and fouled membranes were determined using atomic force microscopy (AFM) images. CA membrane with pore size of 0.45μm showed the most rapid decline in the flux among all membranes due to its irregular and rough surface. ME membranes yielded the greatest steady state flux value followed by PC and PES, while CA membranes had the lowest steady state flux. PC membranes had the greatest pore resistance (Rp) for membranes at all pore sizes. Concentration polarization was observed to be a significant fouling mechanism for all membranes.
2013
Preparation and characterization of microfiltration flat polymeric membranes for biomedical applications The EM3E Master is an Education Programme supported by the European Commission, the European Membrane Society (EMS), the European Membrane House (EMH), and a large international network of industrial companies, research centres and universities (http://www.em3e.eu). Copyright @ Name, FCT/UNL A Faculdade de Ciências e Tecnologia e a Universidade Nova de Lisboa têm o direito, perpétuo e sem limites geográficos, de arquivar e publicar esta dissertação através de exemplares impressos reproduzidos em papel ou de forma digital, ou por qualquer outro meio conhecido ou que venha a ser inventado, e de a divulgar através de repositórios científicos e de admitir a sua cópia e distribuição com objectivos educacionais ou de investigação, não comerciais, desde que seja dado crédito ao autor e editor. Projecto financiado com o apoio da Comissão Europeia. A informação contida nesta publicação vincula exclusivamente o autor, não sendo a Comissão responsável pela utilização que dela possa ser feita. I would like to express my gratitude to Mr. Luca Querze and Mr. Davide Rinaldi for the useful comments, remarks and engagement through the whole process of this master thesis preparation. Furthermore I would like to thank the services and help from Alessia Campisi working in HR department. Additionally I want to mention the contribution of Ing. Nino Gaeta in the organization of my stay in GVS Filter Technology. My deep appreciation also goes to all members of the membrane research group (Fausto Lentini, Felice Sidari, Elsa Caruso) for their advice and assistance. I would like to thank Weibing Feng for SEM analysis and permporometry tests. I would like to thank the examination committee for their advices and comments on my thesis. I would like to thank all my best friends for their support and encouragement. Finally, I would like to thank my family and parents for their love and support.
Mechanical properties of polymeric microfiltration membranes
Journal of Membrane Science, 2019
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Revista de Innovación Sistemática, 2021
Chronic kidney disease is generally complicated by poor care or by ignoring it. Among the causes that influence these conditions are obesity, diabetes, smoking, or genetic inheritance. Coordinated efforts are currently being made in multiple countries to control a strong case rate. The clinical techniques of treatment rely on the efficiency of blood purification (function that´s done by kidneys in organisms). Therefore, there is great interest in the development of devices that accomplish this function. Hemofiltration through porous membranes is an efficient process, but the flow conditions in a microchannel system can be complex. Analysis of blood flow in a parameterized conduit arrangement shows streams with desired trajectories, others are held back (stagnant), and others return to the stream from which it´s separated. In addition, the friction conditions and the reduction of the area drastically reduce the movement of the fluid, promoting clogging and consequently the inhibition...
Impact of wetting agents on the filtration performance of polymeric ultrafiltration membranes
Desalination, 2009
Polymeric membrane flat sheets as well as hollow fibres are widely used in membrane bioreactors in order to separate biologically cleaned water from suspended solids. The polysulfone (PS) flat sheet and polyethersulfone (PES) hollow fibre membranes have been chosen for characterization and to investigate the impact of wetting agents on membrane filtration performance. Virgin PS and PES ultrafiltration membranes were characterized by simple filtration test with deionised water to determine their permeability. It was found that during pure water filtration with hollow fibre PES membranes the permeability was changing when filtration tests were run at permeate fluxes of 15 L/m 2 h, 30 L/m 2 h, 15 L/m 2 h, 50 L/m 2 h and 15 L/m 2 h in subsequent filtration periods. This phenomenon is explained by membrane wettability. Additionally, it has been shown that the permeability of virgin membranes varies in a broad range. The absolute permeability value depends on the degree of pores employment in the filtration and increases with higher transmembrane pressure. In order to wet a maximal number of pores, the membranes were treated with different wetting agents like acetone, isopropyl alcohol and ethanol. The observed changes in permeability demonstrated that the three chosen wetting agents play an important role for the activation of smaller pores through a reduction of the surface tension.
2017
A polypropylene microporous membrane (PPMM) was fabricated by thermally induced phase separation (TIPS) method. The effects of protein size and structure as well as filtration pressure on the membrane performance and fouling mechanisms were investigated using two different proteins, bovine serum albumin (BSA) and collagen, in dead-end filtration setup. Obtained results showed that, for each protein filtration, increasing the operational pressure led to higher irreversible fouling ratio (IFR) and consequently lower flux recovery (FR). Moreover, in collagen filtration, the higher portion of the total fouling ratio (TFR) belonged to reversible fouling ratio (RFR) and the FR of membrane in collagen solution filtration was higher than that in BSA solution filtration at the same operational pressure. The FR values were about 42.48 and 56.32% at 2 bar, 52.28 and 64.53% at 1.5 bar and 65.97 and 75.83% at 0.75 bar for BSA and collagen solutions filtrations, respectively. Investigation of the...
Journal of Membrane Science, 2009
Normal-flow filtration is used frequently in the biopharmaceutical industry for applications such as sterile filtration of fermentation media, buffers and product proteins. Though the membrane pores are much larger than the product protein, protein fouling of the membrane often leads to a decrease in permeate flux at constant feed pressure. Normal-flow microfiltration experiments were conducted using polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) base membranes, PTFE membranes coated with polyvinyl alcohol (PVA) and Teflon AF, and PVDF and polycarbonate membranes coated with PVA and polyvinyl pyrrolidone.
Pore-filled nanofiltration membranes based on poly(2-acrylamido-2-methylpropanesulfonic acid) gels
Journal of Membrane Science, 2005
Strong polyacid gel-filled membranes have been prepared by UV-initiated copolymerization of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and N,N -methylenebisacrylamide within the pores of a microporous polypropylene (PP) substrate. These poly(2-acrylamido-2methylpropanesulfonic acid) (PAMPS) gel-filled membranes were readily prepared with predictable amounts of the incorporated gel polymer (mass gain, MG) provided that threshold values of the degree of cross-linking and monomer concentration were exceeded. Most of the membranes showed large dimensional changes, particularly in their thickness on incorporation of the PAMPS. These changes were related to the amount of PAMPS incorporated into the membranes. In order to determine the polymer volume fractions of the incorporated gels, the partial specific volume of PAMPS (0.575 cm 3 /g) was obtained from density measurements using pycnometry. As a result of increase in thickness (volume) of the membranes, the polymer volume fractions of the PAMPS pore-filling gels were limited to values between 0.01 and 0.06, relatively low values compared to values achieved with other gel-filled membranes based on the same substrate. The Darcy permeability of PAMPS gel-filled membranes exhibits a typical relationship with polymer volume fraction, but the absolute values obtained are much lower than those of other gel-filled membranes previously studied. The lower permeability could be attributed to tightly bound water molecules along polymer chains, which effectively enlarges the hydrodynamic size of polymer chains and narrows the channels for water transport. Using the sphere model based on the Odijk's theory of semidilute polyelectrolyte solutions, the Darcy permeability of PAMPS gel-filled membranes could be calculated with good precision.