Preparation and performance of cellulose acetate/polyethyleneimine blend microfiltration membranes and their applications (original) (raw)
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Polymer International, 1998
AbstractUltrafiltration gains significance when certain chemical species, such as proteins and some toxic heavy metal ions, present in low concentration, have to be selectively removed from a mixture. Separation of metal ions by complexation with macromolecular binding agents and rejection of proteins such as bovine serum albumin, egg albumin, pepsin and trypsin was studied using cellulose acetate–polyurethane blend ultrafiltration membranes. The influence of the composition of the polymers in blend membranes on the separation of metal ions and proteins is discussed. The blend membranes were also characterized by pure water flux, water content, membrane hydraulic resistance, molecular weight cut-off and scanning electron microscopy. The separation of proteins was found to be directly proportional to the molecular weight of the proteins, while the flux displayed an opposite trend, and copper was found to have a higher separation capability than nickel, zinc and cadmium. © 1998 Society of Chemical Industry
Separation and Purification Technology, 2007
Metal ion separation from industrial effluents and protein removal from food and bio-related industrial waste streams are gaining increased visibility due to environmental concern and saving valuable materials. In this work, an attempt has been made to remove the valuable proteins and metal ions using modified cellulose acetate (CA) based membranes prepared in the absence and presence of the polymeric additives such as polyvinylpyrrolidone (PVP) and polyethyleneglycol (PEG 600) in various compositions. Studies were carried out to find the rejection and permeate flux of proteins such as bovine serum albumin (BSA), pepsin and trypsin and metal ions such as Cu(II), Zn(II), Co(II), and Cd(II) using polyethyleneimine (PEI) as the chelating ligand. On increasing concentrations of PVP and PEG, the rejection of proteins and metal ions is decreasing while the permeate flux has an increasing trend. These effects are due to the increased pore formation in the CA membranes because of the additives. In general, it was found that CA/PVP blend membranes displayed higher permeate flux and lower rejection compared to CA/PEG blend membranes at all additive concentrations. The extent of separation of proteins was found to be directly proportional to the molecular weight of the protein while the extent of removal of metal ions depends on the affinity of metal ions to PEI to form macromolecular complexes and the stability of the formed complexes.
Journal of Applied Polymer Science, 1998
The development of cellulose acetate blend membranes using a commercial grade Mycell cellulose acetate and cellulose diacetate with suitable pore structure is discussed. These membranes were characterized in terms of resistance of the membrane, pure water flux, the molecular weight cutoff, water content, pore size, and porosity. The removal of copper metal ions by this blend membrane using polyethyleneimine as a chelating agent was studied. The effects of copper ion concentration and casting solution composition on separation are also discussed. A possible correlation between feed and permeate concentration of copper ion is evaluated.
Journal of Membrane Science, 2000
Characterization and application of ultrafiltration membranes are of great interest today, both as a tool in choosing the proper membrane for the filtration system used and in the development of new and better membranes. Cellulose acetate was blended with polyurethane in a polar solvent in the presence of polyvinylpyrrolidone as an additive. The effects of polymer composition and additive concentration on membrane compaction, pure water flux, water content, membrane hydraulic resistance and morphological studies were discussed. Measurement of transmembrane flux and appropriate macro solute rejection during stirred ultrafiltration of aqueous solutions of proteins and metal ions chelated with polyethyleneimine were carried out individually using CA/PU blend membranes.
Studies on cellulose acetate-polysulfone ultrafiltration membranes
Journal of Membrane Science, 2006
Polymeric blend ultrafiltration membranes based on cellulose acetate and polysulfone were prepared by phase inversion technique in presence of different additive concentrations, polyvinylpyrrolidone, and characterized in terms of compaction time, pure water flux (PWF), water content, membrane resistance and scanning electron microscopy (SEM). The blend membranes were subjected to separation of proteins and heavy metal ions using polyethylenimine as a complexing agent and the results were discussed. The molecular weight cut off of blend membranes was also reported.
Synthesis and characterization of CMC/PVA/PVP composite microfiltration membrane
DESALINATION AND WATER TREATMENT
The aim of this study was to develop a composite membrane by phase inversion using carboxymethyl cellulose (CMC) as a basic material followed by characterization and performance testing. CMC was prepared from cellulose by alkalization and etherification of cellulose. CMC along with polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) were used to prepare composite membranes. Polyethylene glycol (PEG) was used as a pore forming agent. Characterization was done using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), and universal testing machine. SEM results indicated that the addition of PVP resulted in a smoother surface with a pore size ranged 0.1-10 micron as compared to the membrane fabricated without PVP. FTIR spectroscopy gave the bands that are attributed to the dispersion of PVA and PVP in substrate matrix. Weight loss started at 270°C with PVP treatment as compared to 210°C in the absence of PVP indicating the improved thermal stability of the membrane. Salt rejection efficiency was in the following order: NaCl < KCl < CaCl 2 with solutions passed through having 0.1%, 0.3%, 1.0%, and 3.0% salinity. Overall salt removal or salt rejection efficiency ranged from 27% to 37%. It was concluded that PVP had a positive effect on thermal stability, surface morphology, and mechanical properties of the membrane. The properties highlight the potential usage of the synthesized membrane in pretreatment for removal of larger particles such as macromolecules, proteins, colloids, and microbes.
Separation and Purification Technology, 2008
This study presents preparation of cellulose acetate (CA) and aminated polyethersulfone (APES) blend ultrafilrtation membranes by precipitation phase inversion technique in various polymer blend compositions in the presence / absence of PEG 600. Prepared membranes were used for rejection of proteins (bovine serum albumin, egg albumin, pepsin, and trypsin). Toxic heavy metal ions [Cu(II), Zn(II), and Cd(II)] from dilute aqueous solutions were subjected to separation by blend membranes. On increasing APES concentrations, rejection of proteins and metal ions decreases, whereas permeate flux has an increasing trend. Extent of proteins separation was found to be directly proportional to molecular weight of protein. CA / APES blend ultrafilration membranes demonstrated better performance compared to the membranes prepared from pure cellulose acetate.
Ultrafiltration application of cellulose acetate–polyurethane blend membranes
European Polymer Journal, 1999
Cellulose acetate membranes are widely used for reverse osmosis and ultra®ltration applications. Cellulose acetate membranes were prepared by solution blending of cellulose acetate with polyurethane in polar solvent. The eect of varied concentrations of additive, polyvinylpyrrolidone, on the performance of modi®ed cellulose acetate/ polyurethane blend membranes was studied. The cellulose acetate/polyurethane membranes were characterized based on pure water¯ux, compaction, water content, morphological studies and applied for proteins separations by ultra®ltration technique and are discussed in detail. #
Chemical Engineering Journal, 2011
Polyamidehomopolymer and block copolymernanocomposites were prepared by melt processing using a co-rotating Leistritz twin screw extruder. The polymers used werepolyamide 11 (PA11) and poly (ether-block-amide), Pebax 7233. Commercially available nanoclay, Cloisite 30B was chosen as the nanofiller in this study. Particular emphasis was placed on better defining the morphological and performance characteristics of the nanocomposites prepared.Analytical techniques such as X-ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and short-term mechanical tests were employed to characterise the nanocomposite materials.XRD analysis confirmed an exfoliated structure for PA11 nanocomposite at low loading whereas for Pebax 7233, an increase in d 001 spacing suggests an intercalated structure exists. There was no significant change in melting temperature for PA11 and Pebax 7233 due to nanoclay addition; however, the crystallinity was found to decrease as measured by DSC.The performance characteristics of both nanocomposites systems were established using short-term tensile and DMA techniques.A significant increase in storage modulus was observed for both nanocomposite systems investigated.
Protein Separation by Cellulose Acetate/Sulfonated Poly(ether imide) Blend Ultrafiltration Membranes
A process for purifying aqueous solutions containing macromolecular proteins such as bovine serum albumin (BSA), egg albumin (EA), pepsin, and trypsin has been investigated. Protein removal from food and biorelated industrial waste streams are gaining increased visibility due to environmental concern and saving precious materials. Ultrafiltration (UF) processes are largely being applied for protein separation from aqueous streams. In this work, an attempt has been made to separate the valuable proteins using cellulose acetate (CA)/sulfonated poly(ether imide) (SPEI) blend UF membranes prepared in the absence and presence of the additive, polyethyleneglycol (PEG600) in various compositions. The blend membranes were subjected to the determination of pore statistics and molecular weight cut-off (MWCO). Porosity and pore size of the membranes increased with increasing concentrations of SPEI and PEG600 in the casting solution. Similarly, the MWCOs of the blend membranes ranged from 20 to greater than 69 kDa, depending on the various polymer blend compositions. Surface morphology of the blend membranes were analyzed using scanning electron microscopy. Studies were carried out to find the rejection and permeate flux of proteins. On increasing the concentration of SPEI and PEG600, the rejection of proteins is decreasing, whereas the permeate flux has an increasing trend. The effect of hydrophilicity of SPEI on fouling of protein for CA/SPEI blend membranes was also discussed.