Transport of water and alkali metal ions through MFI zeolite membranes during reverse osmosis

Li, Liangxiong; Dong, Junhang; Nenoff, Tina M.

doi:10.1016/j.seppur.2006.06.012

Cited by 93 publications

(102 citation statements)

References 24 publications

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“…Increase in permeate flux with increasing temperature is typical for microprous materials, especially MFI-type zeolites as observed in pervaporation studies which is attributed to activated transport [29,47]. In desalination through the same structures, activated diffusion was also observed by Li et al [8]. They found in their study that both water and ion fluxes increased significantly when raising the feed temperature from 10 °C to 50 °C.…”

Section: Desalination Performancesupporting

confidence: 52%

“…The aperture size of the MFI-type zeolite is around 0.56 nm [8], which is smaller than the sizes of hydrated ions [17] but larger than the kinetic diameter of water. Performance testing of MFI-type zeolite membranes working in RO demonstrated that high rejections of even the smallest ions, including Na + abundantly found in saline waters, are achievable [2,6].…”

Section: Introductionmentioning

confidence: 88%

“…As mentioned earlier, the permeate flux showed a significant increase when increasing the testing temperature to 90 °C. This affected both water and ions, but had a greater impact on the ion permeation than on the water permeation thus resulting in a decrease in ion rejection [8]. This is a special phenomenon which requires further exploration for specialist ion selective applications (e.g.…”

Section: Desalination Performancementioning

confidence: 99%

“…Single layers are a more simplistic approach but the material must possess the required pore size between ions and the water. There have been some studies to date applying different membrane materials such as zeolites [2,3,[6][7][8][9][10], and hybrid organically bridged silica [5] for membrane desalination. Zeolite materials are highly configurable through their chemistry and offer unique frameworks for a wide variety of applications including chemical sensing, water treatment and chemical reaction [2,3,[6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…Na + 0.716 nm, K + 0.662 nm, Ca 2+ 0.824 nm, Table 1) [16]. Following this computational simulation study, several research groups have explored the possibility of using MFI-type zeolite membranes for desalination [2,[6][7][8][9]. The MFI-type zeolite has orthorhombic crystal symmetry with nearly cylindrical, 10-member ring channels.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Desalination Performancesupporting

confidence: 52%