Electrolyte retention of supported bi-layered nanofiltration membranes

Lint, W.B. Samuel de; Zivkovic, Tijana; Benes, Nieck E.; Bouwmeester, Henny J.M.; Blank, Dave H.A.

doi:10.1016/j.memsci.2005.10.004

Cited by 31 publications

(12 citation statements)

References 39 publications

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“…To enable operation in a wide pH range, membranes with two active membrane layers of different materials and different isoelectric points (IEP) are being designed. These bi-layered systems are found to perform better over a large pH range than a membrane with only one type of selective layer (Elmarraki et al ., 2001;Samuel de Lint et al ., 2006).…”

Section: Membrane Polarity and Chargementioning

confidence: 99%

Principles of Membrane Filtration

Hausmann

Duke

Demmer³

2012

Membrane Processing

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Section: Membrane Polarity and Chargementioning

confidence: 99%

Principles of Membrane Filtration

Hausmann

Duke

Demmer³

2012

Membrane Processing

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“…desalination). Materials which possess these properties and have already been demonstrated for desalination are silica [2,3] and zeolites [4][5][6][7][8][9]. Seawater desalination was demonstrated in reverse osmosis mode on MFI type zeolite membranes, which have an intrinsic crystal pore size of 0.55nm [10].…”

Section: Introductionmentioning

confidence: 99%

Structural effects on SAPO-34 and ZIF-8 materials exposed to seawater solutions, and their potential as desalination membranes

et al. 2016

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The effects of saline water on the material properties of two promising salt rejecting structures, SAPO-34 and ZIF-8, were explored for desalination. Immersing SAPO-34 in seawater revealed a release of Al which involved some replacement by Ca, K, Mg and Na. X-ray powder diffraction revealed a robust structure in deionised and sea water solutions. ZIF-8 on the other hand, lost 1% of its mass due to release of Zn into both deionised water and seawater solutions, yet structure remained intact. N2 and positron annihilation lifetime spectroscopy porosimetry techniques revealed loss of surface area and mesopores on both materials, explained by capillary forces acting to close them. Membrane reverse osmosis revealed no liquid water flux for SAPO-34 due to the intactness of the membrane and very small pore size which contributed to prohibitive resistance to liquid water flow. ZIF-8 membranes permeated water, but did not demonstrate significant salt rejection indicating that either the slight mass loss impacted membrane integrity to reject salt, or that liquid water diffusion in ZIF-8 does not follow a salt rejecting path. SAPO-34 and ZIF-8 structures are stable structures for aqueous applications including sea salts, but further work is needed to develop them for reverse osmosis desalination.

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“…High ion rejection properties are essential in tandem with high water diffusion [2]. Nanoporous inorganic membranes have been studied both theoretically and experimentally to reject ions by filtration, utilising single layers [3] and a novel bilayer concept [4,5]. Single layers are a more simplistic approach but the material must possess the required pore size between ions and the water.…”

Section: Introductionmentioning

confidence: 99%

Desalination of seawater ion complexes by MFI-type zeolite membranes: Temperature and long term stability

Zhu

Zhou

Milne

et al. 2014

Journal of Membrane Science

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Desalination of seawater ion complexes by MFI-type zeolite membranes: temperature and long term stability, Journal of Membrane Science, http://dx.doi.org/10.1016/j.memsci. 2013.10.071 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 galley proof before it is published in its final citable 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. 2 high rejection (>93%) for all major seawater ions including Na + (except for K + , 83%) at an applied pressure of 700 kPa and room temperature (22 °C), but showed a continuous decrease in ion rejection when increasing the temperature from 22 °C and 90 °C. Permeation flux of the zeolite membrane significantly increased with increasing in temperature. Upon closer observation of the major cations, size selective diffusion in the zeolite membrane was observed over the temperatures tested. Larger ions Ca 2+ and Mg 2+ were less responsive to temperature than smaller ions Na + and K + . No changes in membrane structure were observed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) after 180 days seawater exposure. However, energy-dispersive X-ray spectroscopy (EDS) mapping on the surface of the membrane revealed a small quantity of tightly bound divalent cations present in the structure, which appear to have penetrated the zeolite, accelerated by temperature. They were suspected to have altered the permstructure, explaining why original high rejections at room temperature were not reversed after heat exposure. The work has shown that zeolite membranes can desalinate seawater, but other unusual effects such as ion selective diffusion as a function of temperature indicate a unique property for desalination membrane materials.

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Electrolyte retention of supported bi-layered nanofiltration membranes

Cited by 31 publications

References 39 publications

Principles of Membrane Filtration

Principles of Membrane Filtration

Structural effects on SAPO-34 and ZIF-8 materials exposed to seawater solutions, and their potential as desalination membranes

Desalination of seawater ion complexes by MFI-type zeolite membranes: Temperature and long term stability

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