The effect of polymer solution composition and film-forming procedure on aromatic polyamide membrane skin layer structure

Wood, H.W.; Sourirajan, S.

doi:10.1016/0021-9797(92)90396-4

Cited by 8 publications

(5 citation statements)

References 42 publications

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“…The Carman–Kozeny equation applies for the particles and pores in the range of >0.25 mm. The pore sizes expected in this study were in the range of 9 to 23 nm as calculated by eq suggested by Wood and Sourirajan r normaln r int = 6.464 The rejection performance suggests pore size to be even smaller, possibly because of particle deformation as explained in section 3.2.3.…”

Section: Resultssupporting

confidence: 57%

Membranes for Organic Solvent Nanofiltration Based on Preassembled Nanoparticles

Siddique

Peeva

Stoikos

et al. 2012

Ind. Eng. Chem. Res.

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A new class of organic solvent nanofiltration (OSN) membranes has been fabricated by assembling nano-sized polymer particles with methacrylate moieties onto the surface of crosslinked polyimide ultrafiltration support membranes. Multiple layers of these nanoparticles create a separation film functionally similar to the top layer of an asymmetric OSN membrane.Nanoscale interstitial spaces formed between the particles serve as permeation channels. In principle, manipulating the size of the nanoparticles can be used to control the dimensions of the interstitial spaces through which permeation occurs. Two different sizes of nanoparticles -120 2 and 300 nm -were used. As expected, membrane separation performance changed with the size of nanoparticles employed due to the changes in interstitial dimensions. Crosslinked polyimide ultrafiltration membranes prepared by phase inversion were coated with successive layers of nanoparticles by spin coating. After coating the nanoparticles were crosslinked by photo initiated free radical polymerization using ultraviolet light (365nm wavelength). In addition to the size of the nanoparticles, the separation performance was also manipulated by changing the thickness of the nanoparticle layer. Membranes were characterized using scanning electron microscopy. The nanofiltration performance of these membranes was evaluated in solvents such as acetone and toluene. The molecular weight cut-off (MWCO) of the membranes was from 200-1,000 g.mol -1 depending upon the nanoparticle diameter and thickness of the nanoparticle layer. Thus membranes with graded nanoscale porosities were successfully fabricated from interconnected nanoparticles providing control over membrane permeation performance.

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Section: Resultssupporting

confidence: 57%

Membranes for Organic Solvent Nanofiltration Based on Preassembled Nanoparticles

Siddique

Peeva

Stoikos

et al. 2012

Ind. Eng. Chem. Res.

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“…Eventually, the macromolecules are rendered paracrystalline, and the resultant membrane can be used as a separation film. 5 The magnitude of an interstitial void in a monolayer of spheres can be determined from geometry considerations, and depends upon the size and packing disposition of the spheres. The geometric values of the interstitial voids in a macromolecule monolayer can also be determined for given values of Rs.…”

Section: Linear Polymer Solutions and Their Resultant Filmsmentioning

confidence: 99%

Some Design Aspects of Aromatic Polyamide Reverse‐Osmosis Membranes

Wood

Sourirajan

1993

Dev. Chem. Eng. Mineral Process.

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Linear-polymer solutions are comparable to a suspension of macromolecule spheres.Macromolecules concentrate at the interface during the membrane-forming procedure. They coalesce with each other suficiently for the su$ace to become a sheet of interconnected macromolecules. Interstitial voids are formed whose magnitude is dependent on the size and packing arrangement of the macromolecules, and is also influenced by the extent of coalescence occurring in the interstitial voids. A subsequent gelation procedure renders the macromolecules paracrystalline. During operation, the membrane allows permeation of solution components primarily through the interstitial voids.Membrane design requires the ability to predict membrane pe~ormance from the precursor casting conditions. This paper illustrates the practical utility of the interstitial void model for membrane design purposes. Some design aspects are presented for various reverse-osmosis membranes made from an aromatic polyamide polymer.

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“…However, as no other significant morphological change could be observed in this layer, different nodule sizes could be an indication of a physical parameter that induces a change in the separation performance of PI OSN membranes. Current transport models [23,50] used in OSN are unable to relate this morphological feature to OSN transport However, Wood and Sourirajan [51] proposed a transport model assuming that the dope solution consists of macromolecular spheres which are crystallised in place during immersion precipitation. Transport through this RO membrane is analysed by convective and diffusive flow through the interstitial spaces.…”

Section: Performance Of Non-crosslinked Membranes In Toluenementioning

confidence: 99%

“…Further assuming that the interstitial voids are formed from closely packed monolayers that are surrounded by three particle spheres, the equivalent crossectional radius of the void (R void ) may be calculated from the following equation [51]:…”

Section: Performance Of Non-crosslinked Membranes In Toluenementioning

confidence: 99%

“…This prompted an investigation into the dilute solution properties of the dope solution at the various solvent compositions.Significant polymer-polymer interactions make it difficult to determine possible macromolecular structures in concentrated polymer solutions. The hydrodynamic volume of a macromolecule is proportional to the M w,app and [Á] of the polymer, with decreased [Á] indicating a more compact conformation[51]. [Á] can be determined from the y intercept of a plot of Á sp /C against C and the slope is proportional to k [Á] where k (Huggin's coefficient) indicates the strength of the polymer solvent interaction.Fig.…”

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confidence: 99%

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Controlling molecular weight cut-off curves for highly solvent stable organic solvent nanofiltration (OSN) membranes

See‐Toh

Silva

Livingston

2008

Journal of Membrane Science

134

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The effect of polymer solution composition and film-forming procedure on aromatic polyamide membrane skin layer structure

Cited by 8 publications

References 42 publications

Membranes for Organic Solvent Nanofiltration Based on Preassembled Nanoparticles

Membranes for Organic Solvent Nanofiltration Based on Preassembled Nanoparticles

Some Design Aspects of Aromatic Polyamide Reverse‐Osmosis Membranes

Controlling molecular weight cut-off curves for highly solvent stable organic solvent nanofiltration (OSN) membranes

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