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Ultrafiltration single pore

Figure 8.2. AFM images of single pores in (a) microfiltration, (b) ultrafiltration and (c) nanofiltration... Figure 8.2. AFM images of single pores in (a) microfiltration, (b) ultrafiltration and (c) nanofiltration...
The most important property characterizing a microporous membrane is the pore diameter (d). Some of the methods of measuring pore diameters are described in Chapter 7. Although microporous membranes are usually characterized by a single pore diameter value, most membranes actually contain a range of pore sizes. In ultrafiltration, the pore diameter quoted is usually an average value, but to confuse the issue, the pore diameter in microfiltration is usually defined in terms of the largest particle able to penetrate the membrane. This nominal pore diameter can be 5 to 10 times smaller than the apparent pore diameter based on direct microscopic examination of the membrane. [Pg.68]

The work described in this chapter is especially concerned with three of the most widely used pressure driven membrane processes microfiltration, ultrafiltration and nanofiltration. These are usually classified in terms of the size of materials which they separate, with ranges typically given as 10.0-0.1 xm for microfiltration, 0.1 p.m-5 nm for ultrafiltration, and 1 nm for nanofiltration. The membranes used have pore sizes in these ranges. Such pores are best visualised by means of atomic force microscopy (AFM) [3]. Figure 14.1 shows an example of a single pore in each of these three types of membrane. An industrial membrane process may use several hundred square meters of membrane area containing billions of such pores. [Pg.523]

Fig. 5.8. Three-dimensional non-contact AFM image of a single pore in an ES625 ultrafiltration membrane. Reprinted from [18], Copyright 1996, with kind permission from Elsevier... Fig. 5.8. Three-dimensional non-contact AFM image of a single pore in an ES625 ultrafiltration membrane. Reprinted from [18], Copyright 1996, with kind permission from Elsevier...
Once successful images of microfiltration membranes have been obtained it is a challenge to move downward in expected pore size or MWCO. Thus, Figure 6.4 shows a single pore in a PCI Membranes ES625 ultrafiltration membrane which has a specified MWCO of 25 000 [2]. [Pg.107]

Figure 6.4 Single pore and pore size distribution of ES625 ultrafiltration membrane. Figure 6.4 Single pore and pore size distribution of ES625 ultrafiltration membrane.
Ultrafiltration membrane (Whatman, Anotop 10), syringe (SGE, 10 mL), holder (Millipore, 13 mm) were assembled as shown in Fig. 7.2. The thicknesses (pore diameters) of the top and bottom layers of ultrafiltration membrane are 59 xm (200 nm) and 1 p,m (20 or 100 nm), respectively. The two layers contain a nearly equal number of cylindrical pores namely, each smaller pore is under a large 200-nm one, which prevents possible interference of the flow fields generated by different small pores at their entrances, i.e., each smaller pore is isolated, so that our study nearly resembles a single pore experiment even many pores are actually used. In each solution, we added an appropriate amount of short linear polystyrene chains with a size smaller than the small pore. They can pass through the small pore by diffusion even without any flow so they served as an internal... [Pg.112]

Formerly, membrane materials consisted mainly of barrier typ>es, sometimes called permeable or semipermeable, in which the gases flowed into and through the pores and interstices, which were of molecular dimensions for example, measured in angstroms. There is the use of materials similar to molecular-sieve adsorbents, for example. For single-phase liquid systems or solutions, the processes may be referred to by the terms dialysis and osmosis, whereas for gas-liquid, gas-solid, or liquid-solid separations, the terms micro- and ultrafiltration are more appropriate. [Pg.6]


See other pages where Ultrafiltration single pore is mentioned: [Pg.527]    [Pg.47]    [Pg.4041]    [Pg.457]    [Pg.356]    [Pg.702]    [Pg.2929]    [Pg.926]    [Pg.364]   
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