Rotating membrane

New membranes have been developed with significantly enhanced mass-transfer characteristics. These membranes include rotating membrane systems that use a torsional oscillation to produce shear rates as high as 150,000 s. Coiled hollow fibres that exploit Dean vortices to increase solute transport and reduce fouling are receiving attention (Zydney, 2000). 

Rotating diffusion cells These techniques bring the two phases in contact at the surface of a rotating membrane filter having well characterized hydrodynamics. 

Rotating membrane emulsification is another type of batch emulsification. In this case a tubular membrane immersed in a continuous phase vessel is rotating itself and its angular velocity creates the shear stress at the membrane surface (Figure 21.14). 

Plasmapheresis typically employs a membrane module of similar configuration as a high-flux hemodialyzer. Alternatively, a rotating membrane separation element is used in which the tendency of the blood cells to deposit on the membrane surface is counteracted with hydrodynamic lift forces created by the rotation. The membrane element and the associated plasmapheresis circuitry are shown in Fig. 49. Worldwide, about 6 million plasmapheresis procedures are performed annually using this system, making this one of the largest biomedical membrane applications after hemodialysis. 

FIGURE 49 (a) Plasmapheresis system and (b) rotating membrane separation device. (Source Baxter Healthcare Corporation.)... 

Serra CA, Wiesner MR, Laine JM (1999), Rotating membrane disk filters design evaluation using computational fluid dynamics, Chem. Eng. J. 72 1-5. 

Kimura, K., Y. Watanabe, and N. Ohkuma (1998). Filtration resistance induced by ammonia oxidizers accumulating on the rotating membrane disk. Water Science Techno. Wastewater Industrial WastewaterTreatment., Proc. 199819th Biennial Conf. Int Assoc, on Water Quality. Part 4, June 21-26, Vancouver, Canada, 38,4—5,443 52. Elsevier Science Ltd., Exeter, England. 

Jaffiin MY. Dynamic shear-enhanced membrane filtration A review of rotating disks, rotating membranes and vibrating system. J. Membr. Sci. 2008 324 7-25. 

Ultrafiltration unit operations would benefit from increased mass transfer coefficients. In addition to improvements in membrane properties, module designs that reduce concentration polarization in the contacting fluid, such as the use of a rotating membrane [87] or module vibration [88], are needed. 

Gough DA, Leypoldt JK. Rotated, membrane-covered oxj en electrode. Anal Chem 1980 52 1126-30. 

Figure20.9 Processing applications ofmembrane emulsification rotating membranes [53, 54, 56] and premix membrane emulsification [49, 51, 57],...

Combining the advantages of microengineered membranes with increased shear at the membrane surfaces is the basis of rotating membranes ( ROME-process ) [53, 54, 62], Mean droplet sizes are in the range of the membrane pore size. 

V. Eisner, Emulsion Processing with a Rotating Membrane (ROME), ETH Reprozentrale Hdnggerberg, Zurich, 2007. 

To category 2 belong the rotating diffusion cell (RDC) [17], the short-time phasecontacting method [18], the rotating stabilized cell (RSC) [21] and the rotating membrane cell (RMC) [22, 23]. 

Figure 3.8 Rotating membrane cell (RMC). One of the phases is supported by a membrane (of diameter 8 mm) which is glued on a perspex cylinder...

DEs (e.g. W/OAV or OAV/0) were prepared by a two-step method applying an additional rotational membrane process (ROME, ETH Ziiiich/Kinematica AG Luzem, CH) and using the same emulsifiers and stabilizers applied for SE (Table 23.1). At first, the SE was prepared by the rotor-stator device at high rotational speed (up to 10,000 rpm) for tK, 15-20 min at constant temperature (22-23 °C) as described before. The primary droplet size was adjusted between 1 and 2 pm, by the rpm of the rotor-stator device and treatment duration. This SE was then used as the disperse phase in the rotary membrane emulsification (ROME) device. The gentle rotational membrane emulsification/foaming process had been developed at the Laboratory of Food Process Engineering (ETH Zurich) within the past decade and reported elsewhere [29,52,39]. The membrane emulsification has... 

Fig. 23.10 Setup for spraying of DEs (W1/0/W2) including rotating membrane double emulsification (step 2) for iron tracer encapsulation in innermost watery phase (Wl) using air-assist nozzles...

Li, Y. B., Zhang, S. G., Li, J. G. (2011). Experimental and theoretical approaches onnnifonn droplets formation from a rationed rotating membrane system. Chemical Engineering Scierute, 66, 788-796. 

Eisner, V. (2007). Emulsions processing with a rotating membrane ROME. PhD Thesis (Diss. ETHNo. 17153), ETH Zurich. 

Graber, M. (2010). Transport phenomena in rotating membrane processed W/O/W emulsions. PhD Thesis (Diss. ETH No. 19079), ETH Zurich. 

Figure 6.3 Examples of rotating membranes used for emulsification (a) Rotating membrane fabricated by deposition of pure carbon layer on the microporous nickel substrate (Schadler and Windhab, 2004, 2005) (b) rotating stainless steel membrane with laser drilled pores (Vladisavljevic and Williams, 2006) (c) a rotating membrane emulsification system in operation (Vladisavljevic and Williams, 2006).

Vladisavljevic GT, Williams RA. 2006. Manufacture of large uniform droplets using rotating membrane emulsification. / Colloid Interface Sci 299 396-402. 

Huber The Huber MBR is radically different from aU other commercial submerged membrane systems, being based on a mechanically moved membrane. The Huber VRM (vacuum rotating membrane) uses flat-sheet membranes of polyethersulfone... 

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