Desalination by pressure osmosis

Merten, U.

doi:10.1016/s0011-9164(00)80017-x

Cited by 89 publications

(61 citation statements)

References 12 publications

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“…This unexpected observation of negative rejection of K + might be due to the piezodialysis [52] on the zeolite membrane. Piezodialysis is the mechanism of salt transport in preference to water, driven by pressure gradient.…”

Section: Desalination Performancementioning

confidence: 85%

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 Performancementioning

confidence: 85%

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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“…The use of polymeric membranes for filtration and separation processes has a considerable number of applications as is in reverse osmosis, 1-3 water purification, 4 chemical and biological separations, 5 gases separation, 6,7 separation of heavy metals from a solution, 8 templates for the growth of some biomaterials, 9 among many others. Owing to these important applications, too much effort has been addressed to the design of new membranes with high selectivity and chemical resistance.…”

Section: Introductionmentioning

confidence: 99%

“…6 Nevertheless, very few efforts have been dedicated to produce membranes with porosity externally controlled. 4 An important achievement is to have the possibility of controlling the pore size and its distribution. For this purpose, some specific compounds focused on the required specific pore size have been designed.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear changes in pore size induced by temperature in the design of smart membranes

Guerrero

Rosas

Rodríguez-Lugo

2010

Polym J

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A new kind of synthetic membranes prepared by crosslinking of two different organic polymers was designed, the membranes has the ability to adjust the pore diameter in a wide range of sizes (from 3 to 100 microns) just by changing the time of thermal treatment in an aqueous media at constant temperature where they are immersed; in this way it is possible to control externally the pore size of the membrane. A nonlinear mathematical model, on the basis of the overlap of the electrical double layers of charged particles, was developed to explain the oscillatory behavior of the pore size when the time of thermal treatment was varied. The model deduced fits correctly to the experimental results and describes the oscillatory behavior of the pore size.

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“…Mathematical models for the mass transport process through RO membranes have been developed and reviewed in detail in the literature [1][2][3][4][5][6][7][8][9][10][11]. These models can be divided into three main groups: the irreversible thermodynamic models, where the local fluxes of solute and solvent are related to the chemical potential differences across the membrane [12][13][14]; the porous flow model, which assumes that water both diffuses and advects through the membrane pores [1,15,16]; and the solution-diffusion model, which assumes that both water and solutes diffuse between the interstitial spaces of the membrane polymer chains [11,17,18].…”

Section: Introductionmentioning

confidence: 99%

Effectiveness-mass transfer units (ε-MTU) model of a reverse osmosis membrane mass exchanger

Banchik

Sharqawy

Lienhard

2014

Journal of Membrane Science

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A strong analogy exists between heat exchangers and osmotic mass exchangers. The effectiveness -number of transfer units (-NTU) method is well-known for the sizing and rating of heat exchangers. A similar method, called the effectiveness -mass transfer units (ε-MTU) method, is developed for reverse osmosis (RO) mass exchangers. Governing equations for an RO mass exchanger are nondimensionalized assuming ideal membrane characteristics and a linearized form of the osmotic pressure function for seawater. A closed form solution is found which relates three dimensionless groups: the number of mass transfer units, which is an effective size of the exchanger; a pressure ratio, which relates osmotic and hydraulic pressures; and the recovery ratio, which is the ratio of permeate to inlet feed flow rates. A novel performance parameter, the effectiveness of an RO exchanger, is defined as a ratio of the recovery ratio to the maximum recovery ratio. A one-dimensional numerical model is developed to correct for the effects of feed-side external concentration polarization and nonlinearities in osmotic pressure as a function of salinity. A comparison of model results to experimental data found in the literature resulted in an average error of less than 7.8%. The analytical ε-MTU model can be used for design or performance evaluation of RO membrane mass exchangers. Keywords

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Desalination by pressure osmosis

Cited by 89 publications

References 12 publications

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

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

Nonlinear changes in pore size induced by temperature in the design of smart membranes

Effectiveness-mass transfer units (ε-MTU) model of a reverse osmosis membrane mass exchanger

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