Flowing liquid membrane modules

FIGURE 13.11 Schematic diagram of a spiral-t)fpe flowing liquid membrane module (1) microporous hydrophobic membrane, (2) mesh spacer, (3) inlet and (9) outlet pipe of feed, (4) inlet and (10) outlet pipe of strip, (5) inlet and (11) outlet tube of organic membrane solution, (6) feed solution, (7) organic LM solution, and (8) strip solution. (From Teramoto, M., Matsuyama, H., and Ohnishi, N., Sep. Sci. Technol., 24, 981, 1989. With permission.)... 

Matsuyama H, Teramoto M et al. Separation and concentration of heavy metal ions by spiral t)fpe flowing liquid membrane module. Water Treat, 1990 5 237-252. 

Teramoto M, Matsuyama H, Ohnishi N. Development of a spiral-type flowing liquid membrane module with high stability and its application to the recovery of chromium and zinc. Sep Sci Technol 1989 24 981-999. 

We can now design a preliminary pilot setup. We use a spiral-type, flowing liquid membrane module, developed by the Teramoto group [87, 88], in which the effective membrane area is about 40% of the total membrane area (the increase of the membrane area is mainly due to blocking of the membrane surface by spacers, and by the adhesive used to seal the sides of the module). For our system, the total feed-side membrane area is 570 m and the total strip-side membrane area is 763 m , in which 360 m is the area needed for the separation of the strip solution concentrated by copper. By designing standard, three-compartment spiral-type BAHLM modules, with 100 m of the membrane on each side (feed and strip), and two-compartment modules, with 200 m of the membrane, we will obtain a setup, of six standard three-compartment modules and one two-compartment module connected in consecutive order (see Fig. 6.7). After the fourth module, we will... 

Hydrophilic (or ion-exchange) membranes were used for designing rotating disk, creeping film, hybrid liquid membrane, and multimembrane hybrid membrane systems, hoUow-fiber LM modules. Hydrophobic membranes were used for designing hybrid liquid membrane, multimembrane hybrid system, flowing LM, hoUow-fiber contained LM, capiUary liquid membrane modules (or contactors). Below, some of these systems are referenced and described shortly. 

A new type of configuration, the flowing liquid membrane (FLM) was studied by Teramoto et al. [20]. In this case, the membrane liquid phase is in motion as the feed and strip phase. In this type of system a plate-and-frame and spiral-wound configuration with flat membrane was used. The scheme of the FLM configuration is drawn in Fig. 7.3A. The hquid phase flows (FLM) between two hydrophobic microporous membranes. The two membranes separate the hquid membrane phase from feed and strip phases. In Fig. 7.3B, it is reported the classical plate-and-frame module employed for the separation of ethylene from ethane [20]. The liquid membrane convection increased the membrane transport coefficient in gas separation. However, the membrane surface packing density (membrane surface area/ equipment volume) is much lower in spiral-wound system than in hollow fiber. 

The concept of cross-flow microfiltration is shown in Figure 16.11, which represents a cross-section through a rectangular or tubular membrane module. The particle-containing fluid to be filtered is pumped at a velocity in the range 1-8 m/s parallel to the face of the membrane and with a pressure difference of 0.1-0.5 MN/m2 (MPa) across the membrane. The liquid penneates through the membrane and the feed emerges in a more concentrated form at the exit of the module.1617 All of the membrane processes are listed in Table 16.2. Membrane processes are operated with such a cross-flow of the process feed. 

Kcurentjes et al. (1996) have also reported the separation of racemic mixtures. Two liquids are made oppositely chiral by the addition of R- or S-enantiomers of a chiral selector, respectively. These liquids are miscible, but are kept separated by a non-miscible liquid contained in a porous membrane. These authors have used different types of hollow-fibre modules and optimization of shell-side flow distribution was carried out. The liquid membrane should be permeable to the enantiomers to be separated but non-permeable to the chiral selector molecules. Separation of racemic mixtures like norephedrine, ephedrine, phenyl glycine, salbutanol, etc. was attempted and both enantiomers of 99.3 to 99.8% purity were realized. 

The principle of operation for a cross-flow filtration system is to recirculate a liquid solution or suspension, usually using a positive displacement pump, through the membrane module, which may be arranged as multiple tubes, a spiral wound sheet or in a plate and frame configuration. The use of... 

In a general way, most of ceramic membrane modules operate in a cross-flow filtration mode [28] as shown in Figure 6.18. However, as discussed hereafter, a dead-end filtration mode may be used in some specific applications. Membrane modules constitute basic units from which all sorts of filtration plants can be designed not only for current liquid applications but also for gas and vapor separation, membrane reactors, and contactors, which represent the future applications of ceramic membranes. In liquid filtration, hydrodynamics in each module can be described as one incoming flow on the feed side gf, which results in two... 

The second type of the HF modules has also been developed by Schlosser group [25,38 0,92,104]. This module enables a cross flow of the liquid membrane phase or its pulsation perpendicular to fibers, as shown in Figure 13.13. The planar HF elements can be assembled for contacting four or more phases. 

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