An appropriate molecular size parameter for porous membranes calibration

ElsevierGarcía Ivars, J.; Iborra Clar, MI.; Alcaina Miranda, MI.; Van Der Bruggen, B. (2015). Comparison between hydrophilic and hydrophobic metal nanoparticles on the phase separation phenomena during formation of asymmetric polyethersulphone membranes. ABSTRACTInorganic nanoparticles have been applied as additive in membrane synthesis for improving different properties from the base polymer such as hydrophilicity, fouling resistance or permselectivity. To investigate the changes caused by the presence of the inorganic nanoparticles in the formation of the membrane structure, two different metallic compounds with opposite hydrophilicity were used as additives: hydrophilic zinc oxide (ZnO) and hydrophobic tungsten disulphide (WS 2 ). For this purpose, the effect of these metal nanoparticles at ultra-low concentrations (0.05 and 0.25 wt% metal nanoparticles/polymer ratio) in the preparation of flat-sheet membranes based on polyethersulphone (PES) by immersion-precipitation method was investigated. Nmethyl-2-pyrrolidone (NMP) was used as solvent. The influence of both metal nanoparticles on the characteristics and permselective properties of PES membranes was studied with microscopic observations, contact angle measurements, and filtration experiments. Although the incorporation of metal nanoparticles could turn the system into thermodynamically unstable, the demixing process during formation of membranes was slightly delayed, suppressing the macrovoid formation (remarkably using WS 2 ).Regardless the nature of the metal nanoparticles, results showed an overall improvement in membrane hydrophilicity and permselectivity by adding metal nanoparticles compared to the control PES membrane, demonstrating that the behaviour of both metal nanoparticles at ultra-low concentrations was very similar.

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“…(12) The intrinsic viscosity of PEG is related to its own molecular weight and it can be calculated using the following equation [41]:…”

Section: Filtration Experimentsmentioning

confidence: 99%

Comparison between hydrophilic and hydrophobic metal nanoparticles on the phase separation phenomena during formation of asymmetric polyethersulphone membranes

García-Ivars

Iborra–Clar

Alcaina–Miranda

et al. 2015

Journal of Membrane Science

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“…One way would be to replace the SE radius with so-called "hydrodynamic volume," i.e., the MW times the intrinsic viscosity of the molecule ([]⅐MW) (20,40). In Fig.…”

Section: Calibration Of Molecular Size To Mwmentioning

confidence: 99%

Ficoll and dextran vs. globular proteins as probes for testing glomerular permselectivity: effects of molecular size, shape, charge, and deformability

Venturoli¹,

Rippe²

2005

American Journal of Physiology-Renal Physiology

393

408

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Venturoli, Daniele, and Bengt Rippe. Ficoll and dextran vs. globular proteins as probes for testing glomerular permselectivity: effects of molecular size, shape, charge, and deformability. Am J Physiol Renal Physiol 288: F605-F613, 2005; doi:10.1152/ajprenal.00171.2004.-Polydisperse mixtures of dextran or Ficoll have been frequently used as molecular probes for studies of glomerular permselectivity because they are largely inert and not processed (reabsorbed) by the proximal tubules. However, dextrans are linear, flexible molecules, which apparently are hyperpermeable across the glomerular barrier. By contrast, the Ficoll molecule is almost spherical. Still, there is ample evidence that Ficoll fractional clearances (sieving coefficients) across the glomerular capillary wall (GCW) are markedly higher than those for neutral globular proteins of an equivalent in vitro Stokes-Einstein (SE) radius. Physical data, obtained by "crowding" experiments or measurements of intrinsic viscosity, suggest that the Ficoll molecule exhibits a rather open, deformable structure and thus deviates from an ideally hard sphere. This is also indicated from the relationship between (log) in vitro SE radius and (log) molecular weight (MW). Whereas globular proteins seem to behave in a way similar to hydrated hard spheres, polydisperse dextran and Ficoll exhibit in vitro SE radii that are much larger than those for compact spherical molecules of equivalent MW. For dextran, this can be partially explained by a high-molecular-size asymmetry. However, for Ficoll the explanation may be that the Ficoll molecule is more flexible (deformable) than are globular proteins. An increased compressibility of Ficoll and an increased deformability and size asymmetry for dextran may be the explanation for the fact that the permeability of the GCW is significantly higher when assessed using polysaccharides such as Ficoll or dextran compared with that obtained using globular proteins as molecular size probes. We suggest that molecular deformability, besides molecular size, shape, and charge, plays a crucial role in determining the glomerular permeability to molecules of different species. capillary permeability; polysaccharides; macromolecules; reflection coefficient; transport POLYDISPERSE MIXTURES OF DEXTRAN, and more recently Ficoll, are frequently used as molecular probes in studies of glomerular permselectivity. After being filtered through the glomerular capillary wall (GCW), polysaccharides, unlike proteins, are left unreabsorbed by the proximal tubules. This implies that their sieving coefficients (), i.e., their filtrate-to-plasma concentration ratios, can be determined directly from their urinary clearances relative to that of a glomerular filtration rate marker (e.g., inulin). Infusing polydisperse mixtures of dextran or Ficoll and using chromatographic techniques to fractionate plasma and urine samples make it possible to simultaneously determine the for a wide spectrum of different-sized molecular probes, provided that proper size calibrations ...

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“…The hydrodynamic radii (r hyd ) of the PEG molecules were calculated as a function of the molecular weight using Figure 2 (Meireles et al 1995, Causserand et al 2004:…”

Section: Resultsmentioning

confidence: 99%

Towards green membranes: preparation of cellulose acetate ultrafiltration membranes using methyl lactate as a biosolvent

Medina-González

Aimar

Lahitte

et al. 2011

International Journal of Sustainable Engineering

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Ultrafiltration membranes were prepared using cellulose acetate (CA) as a polymer, LiCl and CaCl 2 as porogens and methyl-(S)-lactate as a solvent. CA, methyl lactate and the porogens used in this work are obtained from renewable resources; they are biodegradable, non-toxic and non-volatile organic compounds. Flat sheet ultrafiltration membranes were prepared by the phase inversion technique. A molecular weight cut-off between 15 and 35 kDa (polyethylene glycol) and pure water permeability between 13 and 177 litres h 21 m 22 bar 21 were obtained. These parameters are in the ideal range for water treatment industry. Improvement of pollutant degree and ecotoxicity of the process was evaluated by 'green' metrics by the P (pollutants, persistent and bioaccumulative) and E (ecotoxicity) parameters. Both of these variables were recorded as zero using our method. This study represents a step ahead towards the production of ultrafiltration polymeric membranes by a 'greener' process than current methods.

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An appropriate molecular size parameter for porous membranes calibration

Cited by 101 publications

References 20 publications

Comparison between hydrophilic and hydrophobic metal nanoparticles on the phase separation phenomena during formation of asymmetric polyethersulphone membranes

Comparison between hydrophilic and hydrophobic metal nanoparticles on the phase separation phenomena during formation of asymmetric polyethersulphone membranes

Ficoll and dextran vs. globular proteins as probes for testing glomerular permselectivity: effects of molecular size, shape, charge, and deformability

Towards green membranes: preparation of cellulose acetate ultrafiltration membranes using methyl lactate as a biosolvent

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