The Origin of Large Pores on Aromatic Polyamide Membrane Surfaces

Wood, H.W.; Sourirajan, S.

doi:10.1006/jcis.1993.1372

Cited by 5 publications

(4 citation statements)

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“…Nucleation dominates the polymer lean phases and contributes to the formation of a highly porous membrane. The pores formed as the voids between the spheres are thus higher when the matrix is formed by larger spherical sizes [33,34]. Figure 4 depicts the pore size distribution of the developed membranes.…”

Section: Membrane Pore Size and Distributionmentioning

confidence: 99%

“…Nucleation dominates the polymer lean phases and contributes to the formation of a highly porous membrane. The pores formed as the voids between the spheres are thus higher when the matrix is formed by larger spherical sizes [33,34]. The slight difference in pore size of PVDF and PVDF/PEG-0 membranes can be explained by the role of PEG and LiCl as the additives in pronouncing the impact of thermodynamic rather than the kinetic.…”

Section: Membrane Pore Size and Distributionmentioning

confidence: 99%

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Development of Hydrophilic PVDF Membrane Using Vapour Induced Phase Separation Method for Produced Water Treatment

et al. 2020

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During the production of oil and gas, a large amount of oily wastewater is generated, which would pollute the environment if discharged without proper treatment. As one of the most promising treatment options, membrane material used for oily wastewater treatment should possess desirable properties of high hydraulic performance combined with high membrane fouling resistance. This project employs the vapor induced phase separation (VIPS) technique to develop a hydrophilic polyvinylidene fluoride (PVDF) membrane with polyethylene glycol (PEG) as an additive for produced water treatment. Results show that thanks to its slow nonsolvent intake, the VIPS method hinders additive leaching during the cast film immersion. The results also reveal that the exposure of the film to the open air before immersion greatly influences the structure of the developed membranes. By extending the exposure time from 0 to 30 min, the membrane morphology change from typical asymmetric with large macrovoids to the macrovoid-free porous symmetric membrane with a granular structure, which corresponds to 35% increment of steady-state permeability to 189 L·m−2h−1bar−1, while maintaining >90% of oil rejection. It was also found that more PEG content resides in the membrane matrix when the exposure time is extended, contributes to the elevation of surface hydrophilicity, which improves the membrane antifouling properties. Overall results demonstrate the potential of VIPS method for the fabrication of hydrophilic PVDF membrane by helping to preserve hydrophilic additive in the membrane matrices.

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Section: Membrane Pore Size and Distributionmentioning

confidence: 99%

“…Nucleation dominates the polymer lean phases and contributes to the formation of a highly porous membrane. The pores formed as the voids between the spheres are thus higher when the matrix is formed by larger spherical sizes [33,34]. The slight difference in pore size of PVDF and PVDF/PEG-0 membranes can be explained by the role of PEG and LiCl as the additives in pronouncing the impact of thermodynamic rather than the kinetic.…”

Section: Membrane Pore Size and Distributionmentioning

confidence: 99%

Development of Hydrophilic PVDF Membrane Using Vapour Induced Phase Separation Method for Produced Water Treatment

et al. 2020

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“…Equation (8) shows that when the CaClz concentration is at or above CaC12*, Rb2 is greater than rs xs when Rs is greater than 56.7 A. It is interesting to note that the minimum calculated Rs [equations (1) and (2)] in this PA/DMAc/CaClZ system at CaC12* is 55.8 A.…”

Section: Rs/rs Xs = [(4 -T C ) / T C ] -mentioning

confidence: 82%

“…The critical CaClZ/PA ratio (CaC12*) is 0.33 g of CaC12 er g of PA.4 From equation (8), ARb2 equals zero at CaC12* when Rs equals 56.7 A. Equation (8) shows that when the CaClz concentration is at or above CaC12*, Rb2 is greater than rs xs when Rs is greater than 56.7 A.…”

Section: Rs/rs Xs = [(4 -T C ) / T C ] -mentioning

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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