Wetting Study of Hydrophobic Membranes via Liquid Entry Pressure Measurements with Aqueous Alcohol Solutions

Garcı́a-Payo, M.C.; Izquierdo-Gil, M.A.; Fernández‐Pineda, C.

doi:10.1006/jcis.2000.7106

Cited by 211 publications

(117 citation statements)

References 23 publications

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“…A similar method has been presented by Garcia-Payo et al [17]. In their investigations, a small capillary with 1 mm of inner diameter is connected to the lower chamber.…”

Section: Experimental Determination Of Lepmentioning

confidence: 94%

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Theoretical and Experimental Approaches of Liquid Entry Pressure Determination in Membrane Distillation Processes

Rácz¹,

Kerker²,

Kovács³

et al. 2014

Period. Polytech. Chem. Eng.

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Membrane distillation (MD) is a thermally driven separation process that employs a hydrophobic membrane as a barrier for IntroductionMembrane distillation (MD) is a thermally driven separation technique using microporous hydrophobic membranes and performing on the principles of vapor-liquid equilibrium under different configurations. In this process, only volatile compounds (mainly water) of the feed stream evaporate at the membrane pore entrance, cross the membrane pores in vapor phase to finally be either condensed or removed as a vapor from a membrane module. The hydrophobic nature of the membrane prevents the pores from wetting by capillary forces. MD is known as a promising technology for many applications such as desalting seawater, brackish water, highly saline water [1,2], and removing organic compounds and heavy metals from aqueous solutions [3,4]. MD has also been used to manage waste water such as radioactive waste waters, oily waste waters [5], where the product could be safely discharged to the environment or the waste streams could be reused in an appropriate industrial activity. In biotechnology and food processing applications, MD has also been found as a promising tool, for instance, for removing ethanol and other metabolites from fermentation broths [6], for gentle concentration of valuable compounds in fruit juices [7], and in herb extract such as Ginseng [8].MD has many attractive features as compared to conventional separation processes. Low operating temperatures (~30-70°C) is one of them since the feed is not necessarily heated up to the boiling point like in thermal distillation. Thus, MD may advantageously utilize alternative energy sources, such as solar energy, geothermal energy, waste heats from power plant, etc. [9]. Compared with pressure driven membrane filtration processes such as nanofiltration or reverse osmosis, lower operating pressure translates to lower equipment costs and increased process safety. It is worth highlighting that membrane fouling in MD seems to be less of a problem for many applications than that in pressure-driven filtration processes [10].MD is, however, attended by some drawbacks. Compared to reverse osmosis, MD is known to have a lower permeate flux, and the susceptibility of permeate flux to processing conditions, particularly to temperature and concentration, is considerably high. Also, the trapped air within the membrane pores

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“…A similar method has been presented by Garcia-Payo et al [17]. In their investigations, a small capillary with 1 mm of inner diameter is connected to the lower chamber.…”

Section: Experimental Determination Of Lepmentioning

confidence: 94%

“…However, surface tension, γ L , decreases sharply when solutions contain organic solutes or surfactants. If the concentration of surfactants becomes sufficiently high to exceed a certain critical value, a spontaneous wetting of membrane occurs [17]. Wetting can be directly measured by contact angle.…”

Section: Theoretical Description Of Liquid Entry Pressurementioning

confidence: 99%

Theoretical and Experimental Approaches of Liquid Entry Pressure Determination in Membrane Distillation Processes

Rácz¹,

Kerker²,

Kovács³

et al. 2014

Period. Polytech. Chem. Eng.

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“…Thus, thoroughly investigations are carried out in this work to evaluate if these membranes are suitable for seawater desalination by means of vacuum membrane distillation (VMD) [30][31][32][33][34]. To our best knowledge, this is the first time that MOF-functionalized alumina membranes are used in MD desalination applications.…”

Section: Introductionmentioning

confidence: 99%

Metal–Organic Framework-Functionalized Alumina Membranes for Vacuum Membrane Distillation

Zuo

Chung

2016

Water

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Nature-mimetic hydrophobic membranes with high wetting resistance have been designed for seawater desalination via vacuum membrane distillation (VMD) in this study. This is achieved through molecular engineering of metal-organic framework (MOF)-functionalized alumina surfaces. A two-step synthetic strategy was invented to design the hydrophobic membranes: (1) to intergrow MOF crystals on the alumina tube substrate and (2) to introduce perfluoro molecules onto the MOF functionalized membrane surface. With the first step, the surface morphology, especially the hierarchical roughness, can be controlled by tuning the MOF crystal structure. After the second step, the perfluoro molecules function as an ultrathin layer of hydrophobic floss, which lowers the surface energy. Therefore, the resultant membranes do not only possess the intrinsic advantages of alumina supports such as high stability and high water permeability, but also have a hydrophobic surface formed by MOF functionalization. The membrane prepared under an optimum condition achieved a good VMD flux of 32.3 L/m 2 -h at 60 • C. This study may open up a totally new approach for design of next-generation high performance membrane distillation membranes for seawater desalination.

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“…In the MD process, the force preventing process liquid wetting the membrane pores results from both the hydrophobicity of membrane material and the liquid surface tension. The lowest wetting pressure, the Liquid Entry Pressure (LEP) [1] can be calculated from …”

Section: Introductionmentioning

confidence: 99%

Performance of asymmetric hollow fibre membranes in membrane distillation under various configurations and vacuum enhancement

Zhang

Duke

et al. 2010

Journal of Membrane Science

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Hollow fibre membrane distillation (MD) modules have a more compact structure than flat sheet membrane modules, providing potentially greater advantage in commercial applications. In this paper, a high-flux asymmetrically-structured hollow fibre MD module was tested under various conditions. The results show that increasing velocity and temperature are positive for flux, and salt rejection was more than 99% over the entire experimental range. The hollow fibre module also showed great variation in flux when altering the hot feed flow from the lumen side to the shell side of the fibre, and this phenomenon was analysed based on the characterisation of the asymmetric structure of the hollow fibre. The largest mass transfer resistance was determined to be in the small pore size skin layer on the outer surface of the membrane, and having the hot feed closest to this surface provided the greatest vapour pressure difference across this high resistance mass transfer layer. The results also show that placing the suction pump on the permeate outlet increased the flux by lowering the pressure within the pore and hence increased the rate of vapour mass diffusion. A maximum flux of 19 Lm -2 h -1 was obtained at 85˚C when hot feed was entering the shell side, and the mass transfer coefficient was relatively constant across the entire temperature range when operated at high velocities. These outcomes suggest that asymmetric hollow fibre MD modules should be operated with hot brine feed closest to the high resistant skin layer, and that vacuum enhanced MD further increases vapour transport and flux.

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Wetting Study of Hydrophobic Membranes via Liquid Entry Pressure Measurements with Aqueous Alcohol Solutions

Cited by 211 publications

References 23 publications

Theoretical and Experimental Approaches of Liquid Entry Pressure Determination in Membrane Distillation Processes

Theoretical and Experimental Approaches of Liquid Entry Pressure Determination in Membrane Distillation Processes

Metal–Organic Framework-Functionalized Alumina Membranes for Vacuum Membrane Distillation

Performance of asymmetric hollow fibre membranes in membrane distillation under various configurations and vacuum enhancement

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