Transport Phenomena in Nanofiltration Membranes

Bandini, Serena; Bruni, Luigino

doi:10.1016/b978-0-08-093250-7.00006-2

Cited by 13 publications

(11 citation statements)

References 103 publications

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“…The thickness of the skin layer has also been considered as an important property of an RO membrane governing water and solute transport. According to the solution-diffusion model [23][24][25], permeation of solutes and solution through RO membranes occurs via their penetration into the membrane material and diffusion through the RO membrane. The key role of the polymeric membrane thickness on solute permeation can also be supported by the finding that the thickness is inversely proportional to water permeance and there is a trade-off between water permeance and solute selectivity [26,27].…”

Section: Introductionmentioning

confidence: 99%

Transport of small and neutral solutes through reverse osmosis membranes: Role of skin layer conformation of the polyamide film

Fujioka

O’Rourke

Michishio

et al. 2018

Journal of Membrane Science

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The polyamide skin layer of reverse osmosis (RO) membranes was characterised using advanced and complementary analytical techniques to investigate the mechanisms underlying the permeation of contaminants of emerging concern in potable water reuse -Nnitrosodimethylamine (NDMA) and N-nitrosomethylethylamine (NMEA). This study used five RO membrane samples with similar membrane properties. The five RO membrane samples spanned over a large range of water permeance (0.9-5.8 L/m 2 hbar) as well as permeation of NDMA (9-66%) and NMEA (3-29%). Despite such distinctthese differences among the five RO membranes, characterisations of the skin layer using positron annihilation lifetime spectroscopy, atomic force microscopy and field emission scanning electron microscopy revealed almost no variation difference in their free-volume hole-radius (0.270-0.275 nm), effective surface area (198-212%) and thickness (30-35 nm) of the skin layer. The results suggest that there could be other RO skin layer properties, such as the interconnectivity of the protuberances within the polyamide skin layer additional to the free-volume hole-size and thickness of the skin layer, which can also govern water and solute permeation.

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Section: Introductionmentioning

confidence: 99%

Transport of small and neutral solutes through reverse osmosis membranes: Role of skin layer conformation of the polyamide film

Fujioka

O’Rourke

Michishio

et al. 2018

Journal of Membrane Science

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“…The equations used were selected for uncharged solutes and considering slit-like pores (Bandini and Bruni, 2010): (10) where (%) is the calculated real rejection of glucose, Pe (dimensionless) is the Peclet number, (dimensionless) is the equilibrium partition coefficient and K i,c (dimensionless)is the hindrance factor for convection.…”

Section: Donnan Steric Pore Model and Dielectric Exclusion Model (Dspmentioning

confidence: 99%

Nanofiltration of glucose: Analysis of parameters and membrane characterization

Almazán

Romero-Dondiz

Rajal

et al. 2015

Chemical Engineering Research and Design

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Please cite this article as: Almazán, J.E., Romero-Dondiz, E.M., Rajal, V.B., Castro-Vidaurre, E.F.,Nanofiltration of glucose: analysis of parameters and membrane characterization, Chemical Engineering Research and Design (2014), http://dx.doi.org/10. 1016/j.cherd.2014.09.005 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 4251006.E-mail address: emilioalmazan8787@gmail.com AbstractMembrane characterization and modeling of nanofiltration processes of uncharged solutes are of special interest for the food industry. In this work two commercial membranes, DK and DL, were used to concentrate glucose solutions. Membranes were characterized according hydrophobicity, thickness, porosity, and hydraulic permeability. The influence of pressure and concentration of glucose on the permeate flux and rejection were studied. Both membranes presented a great potential for the food industry due to their high rejection of glucose. The osmotic pressure model was combined with film theory and the real driven force was calculated taking into account the osmotic pressure and the concentration polarization. Both phenomena influenced the process (concentration polarization only in the most dilute solutions at low pressure) and the permeability for glucose solutions was similar to the hydraulic permeability. A mathematical model based on the Donnan-Steric Pore Model was used to determine the pore radius and the effective thickness of both membranes. As the concentration inside the pore (needed for the calculations) is difficult to measure experimentally, various alternatives wereproposed. The average of the concentration at the interface and permeate best fitted the experimental data. The model was applied successfully; the maximum error was 8% within the range of concentrations (5 -100 g/L) for the DL membrane and 5% for the DK membrane up to 50 g/L.Page 2 of 26 A c c e p t e d M a n u s c r i p t 2 HighlightsTwo membranes were characterized and used to concentrate glucose solutions Both membranes presented a great potential due to their high rejection of glucoseThe osmotic pressure and concentration polarization effects were taken into accountMembrane pore radius and effective thickness were determinedThe model fitted successfully the experimental data with maximum errors of 8%

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“…In general, the higher ionic strength of the separated solutions resulted in a higher value of the total volumetric charge of the membrane. It should be noted that Xd values for all model solutions were values obtained for the experiments which reached the steady state and these values should not be confused with the fixed membrane charge because the Xd relates all electrokinetic phenomena present in the vicinity of membrane surface and not only those related to the membrane surface as it is in the case of fixed membrane charge [62][63][64]. The achieved Xd value for MS1 (3.6 g/L succinic acid of pH = 9.7 regulated with granulate NaOH) equal to −35.73 mol/m 3 may indicate the presence of strong electrostatic repulsion between succinate anions present in aqueous solution and membrane surface functional groups, hence the Xd reached a negative value and retention achieved 78%.…”

Section: Variation Of the Overall Volume Charge Densities In Relationmentioning

confidence: 99%

Assessment of the Total Volume Membrane Charge Density through Mathematical Modeling for Separation of Succinic Acid Aqueous Solutions on Ceramic Nanofiltration Membrane

et al. 2019

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Nanofiltration of aqueous solutions of succinic acid with the addition of sodium hydroxide or magnesium hydroxycarbonate has been investigated experimentally and modeled with the comprehensively described Donnan-Steric partitioning model. The experimental retentions of acid at the same pH varied between 16% and 78%, while the estimated total volume membrane charge densities were in the range of −35.73 and +875.69 mol/m 3 . This work presents a novel insight into the modeling of nanofiltration and investigates the relations between the estimated total volume membrane charge densities, ionic strength, and component concentration on the performance of ceramic membrane. In addition, this study takes into consideration other parameters such as pH regulation and viscosities of solutions.

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Transport Phenomena in Nanofiltration Membranes

Cited by 13 publications

References 103 publications

Transport of small and neutral solutes through reverse osmosis membranes: Role of skin layer conformation of the polyamide film

Transport of small and neutral solutes through reverse osmosis membranes: Role of skin layer conformation of the polyamide film

Nanofiltration of glucose: Analysis of parameters and membrane characterization

Assessment of the Total Volume Membrane Charge Density through Mathematical Modeling for Separation of Succinic Acid Aqueous Solutions on Ceramic Nanofiltration Membrane

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