Elsevier

Filtration & Separation

Volume 42, Issue 7, September 2005, Pages 16-21
Filtration & Separation

Cover story
Nanofiltration: properties and uses

https://doi.org/10.1016/S0015-1882(05)70617-0Get rights and content

Filtration + Separation investigates two aspects of filtration at the nano level. Firstly, Koch Membrane Systems' Henia and Jorge Yacubowicz give us an introduction to nanofiltration (below). And on page 22, we turn our attention to the production of nanofibres…

Section snippets

Nanofiltration - Properties and uses

Modern crossflow filtration technology has principally evolved during the last thirty years, following the significant advancements in polymer chemistry over the same time. Today, a vast majority of crossflow filtration installations utilise polymeric membranes. Virtually all commercial nanofiltration membranes are polymeric.

Nanofiltration (NF) is a crossflow, pressure driven process that is characterised by a membrane pore size corresponding to molecular weight cutoff of approximately 200 –

Transport mechanism in NF membranes

NF membranes are often categorised as “loose” reverse osmosis (RO) membranes. The differences between the two, however, are significant. The most notable difference is the ability of NF membranes to selectively reject divalent ions, while passing monovalent ions. It is a common belief that NF and RO membranes do not have distinct pores, as in ultrafiltration and microfiltration membranes. Although recent studies using Atomic Force Microscopy (AFM) suggest that pores of NF membranes can be

Parameters affecting the performance of NF membranes

When designing a NF process, one should consider several operating parameters. The most important operating parameters affecting the performance of NF membranes are similar to those for most crossflow filtration processes:

  • Pressure: Pressure difference is the driving force responsible for a NF process. The effective driving pressure is the supplied hydraulic pressure less the osmotic pressure applied on the membrane by the solutes. NF provides good separation at net pressures of 150 psi

Applications of NF membranes

Due to their unique separation properties, NF membranes are widely used in industry. It is advantageous to use NF membranes when:

Nanofiltration spiral system.

  • It is not necessary to retain monovalent salts: The application of NF can permit operation at lower pressure and with less energy consumption.

  • A separation between low molecular weight organic material and a monovalent salt is desired: i.e. separation of lactose from ash; separation of dyes from sodium chloride.

  • Purification of

About the authors:

Henia Yacubowicz holds a M.Sc. degree in Chemical Engineering from Technion, the Israeli Institute of Technology. She is currently the manager of the Industrial process technology department at KMS, where she has been working for the last 9 years. Before joining KMS she worked for MPW (Membrane Products Kiryat Weizman, Israel) as a project manager in the NF membrane development department.

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Cited by (18)

  • Polythyleneimine-modified original positive charged nanofiltration membrane: Removal of heavy metal ions and dyes

    2019, Separation and Purification Technology
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    Especially for drinking water, the pollution provoked by of heavy metals and dyes is toxic and irreversible, promoting a huge impact on the purification of the world’s water environment [5–9]. A nanofiltration (NF) membrane with a molecular weight cut-off value (MWCO) of 200–1000 and pore size of 1–2 nm has caused scholars extensive applications in water purification and pollution control, due to its excellent performance, low pressure, high expand ability, low energy consumption and high separation efficiency [10–14]. For example, the operating pressure of reverse osmosis membrane is generally between 1.5 MPa and 10.5 MPa, while the operating pressure of NF membrane is about 0.1–2.0 MPa, And the if membrane can retain 99% of the dye and 98% of the salt in the dye desalination.

  • The averaged potential gradient approach to model the rejection of electrolyte solutions using nanofiltration: Model development and assessment for highly concentrated feed solutions

    2015, Separation and Purification Technology
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    Since 1970s, the field of pressure-driven separation techniques has been push forward by the increasing exigencies of efficiency, prevailing as a cheap, sustainable and reliable solution for separation or concentration operations [1]. The growing need for a technology coupling the high retention rate of reverse osmosis (RO) with the moderate pressure difference used in ultrafiltration (UF) led to the development of nanofiltration (NF), a promising technique which already found applications at industrial scales [2]. The majority of the nanofiltration membranes are polyamide thin-film composite (TFC) [3].

  • Nanofiltration of glucose: Analysis of parameters and membrane characterization

    2015, Chemical Engineering Research and Design
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    Many academic and industrial research projects in this area are also in progress (Drioli and Fontananova, 2004; Drioli et al., 2011; Strathmann, 1999). NF membranes have properties in between those of ultrafiltration and reverse osmosis membranes and exceptional stability at very low or high pH, very high temperatures or organic solvent media (Yacubowicz and Yacubowicz, 2005). The separation mechanism of these membranes involves steric and electrical (Donnan) effects.

  • Comparison of two nanofiltration membrane reactors for a model reaction of olefin metathesis achieved in toluene

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    Besides the petroleum industry, the pharmaceutical industry also uses OSN, but for extraction and/or purification of Active Pharmaceutical Ingredients (APIs). Once again, membranes are based on PI or PDMS [4–11] and, in most cases, solvents are mixtures made of water and organic polar solvents, such as alcohols. At laboratory scale, part of the initial driving force for the development of OSN has been the recovery of components of high added value.

  • Separation of potassium clavulanate and potassium chloride by nanofiltration: Transport and evaluation of membranes

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    This process has as some advantages: the operation at low pressures when compared to reverse osmosis; the high fluxes attained; a considerable retention of multivalent anionic salts; an also high retention of organic molecules of molecular weight over 300 Da and the relatively low investment and low cost of operation and maintenance [10]. According to Yacubowicz and Yacubowicz [11], a crossflow nanofiltration process is characterized by a membrane pore size corresponding to molecular weight cut-offs (MWCO) around 200–1000 Da, working at pressures of 150–500 psi (10–34 bar). Some properties of the solutes play a key role as, obviously, their molecular weight.

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About the authors:

Henia Yacubowicz holds a M.Sc. degree in Chemical Engineering from Technion, the Israeli Institute of Technology. She is currently the manager of the Industrial process technology department at KMS, where she has been working for the last 9 years. Before joining KMS she worked for MPW (Membrane Products Kiryat Weizman, Israel) as a project manager in the NF membrane development department.

Jorge Yacubowicz holds a D.Sc. degree in Chemical Engineering from Technion, the Israeli Institute of Technology, specialising in polymeric materials. He is currently a NF product manager and a sales manager at KMS, where he has been working for the last 9 years. Before he joined KMS he worked for MPW (Membrane Products Kiryat Weizman, Israel) as the manager of the process development department, and later as marketing manager.

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