Effect of Membrane Type

Due to the importance of cake formation and flux dependence on deposition, membrane type was not examined in this section. It was anticipated that aggregate characteristics were more important than membrane type. 

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In supported liquid membranes, a chiral liquid is immobilized in the pores of a membrane by capillary and interfacial tension forces. The immobilized film can keep apart two miscible liquids that do not wet the porous membrane. Vaidya et al. [10] reported the effects of membrane type (structure and wettability) on the stability of solvents in the pores of the membrane. Examples of chiral separation by a supported liquid membrane are extraction of chiral ammonium cations by a supported (micro-porous polypropylene film) membrane [11] and the enantiomeric separation of propranolol (2) and bupranolol (3) by a nitrate membrane with a A/ -hexadecyl-L-hydroxy proline carrier [12]. 

Investigation of the effect of membrane type on the interfacial transfer of methyl nicotinate... 

TABLE 13. Effect of Membrane Type on Phosphorus Rejection Rate and Permeate Flux. 

Gallagher SJ, Trollet L, Carter TP, Heard CM. Effects of membrane type and liquid/liquid phase boundary on in vitro release of ketoprofen from gel formulations. ] Drug Target 2003 11(6) 373-379. 

Eksangsri T, Habaki H, Kawasaki J. Membrane-based extra ction of cholesterol lowering drug Effect of membrane type on extraction. Sep Purif Technol 2005 46 63-71. 

In this mixing order (C PS), particles are generally stable due to the presence of adsorbed organics on their surface. Effects of membrane type, organic tt pe and concentration, coDoid size, as well as solution chemistty (pH and calcium concentration) will now be examined for this system. The effects of pressure and stirring were not examined for the OPS system, as no cake was formed in most cases. 

Figure 6.12 Effect of membrane type on UV, j, JDOC ratio in permeates at different organic concentrations (15 mgL NOM concentrate, 20 mM NaCl, pH 7).

Table 7.29 Effect of membrane type (12.5 rngU DOC HA, 2.5 mM CaClf...

The catalytic effect of the type of mixed electrodes occiu s also in a ntunber of bio-redox reactions on bio-membranes and also on enzymes as shown in Fig. 11-4 ... 

X-Y Liu, Q Yang, N Kamo, J Miyake. Effect of liposome type and membrane fluidity on drug-membrane partitioning analyzed by immobilized liposome chromatography. J Chromatogr A 913 123-131, 2001. 

Figure 6.10 Effect of solute type and concentration on flux through the same type of ultrafiltration membrane operated under the same conditions [15]. Reproduced from M.C. Porter, Membrane Filtration, in Handbook of Separation Techniques for Chemical Engineers, P.A. Schweitzer (ed.), p. 2.39, Copyright 1979, with permission of McGraw-Hill, New York, NY...

To study the possible effect of membrane biophysical properties on drug accumulation, the lipid composition of membranes has deliberately been altered by growing cells in the presence of anionic phospholipids, saturated or unsaturated fatty acids, or other components affecting membrane properties, e.g. cholesterol [102, 103]. The accumulation of drugs in MDR hamster cell lines (CHRC5) was increased when membrane properties were altered. For this purpose the cells were cultured in a medium supplemented with C17 0 fatty acid. The cells showed an extent of vinblastine accumulation similar to that found in the sensitive wild-type counterparts (AB1) (Figure 5.15) [103]. 

Table I shows the effect of membrane thickness on the response times for the two different types of Dacron mesh support (internal and external) used for the membranes in the flow cell. Thickness increases the response time for both the pH and glucose concentration changes. Use of the internally incorporated Dacron mesh may possibly decrease the response time due to an increase in the porosity of the gel allowing greater solute transport within the membranes.

Phattaranawik, J., Jiraratananon, R., and Eane, A.G. Effects of net-type spacers on heat and mass transfer in direct contact membrane distillation and comparison with ultrafiltration studies, J. Membr. Sci., 217, 193, 2003. 

The process conducted in batch-type counter-flow apparatus (Figure 30.17) equipped with capillary PP Acccurel membranes showed good effectiveness of membrane distillation for purification of radioactive waste. Permeate obtained was pure water. All solutes together with radioactive compounds were rejected by the hydrophobic membrane. At tenfold volume reduction of the initial portion of waste, approximately tenfold concentration of radioactivity in the retentate stream was reached, while radioactivity of permeate retained on the level of namral background (Figure 30.18). As was observed in experiments small sorption in the system took place. However, permeate was free of radioactive substances and other dissolved compounds, the concentration and radioactivity factors sometimes slightly differed from volume reduction factors. 

Shukla, J.P., Kumar, A., and Singh, R.K., Effect of solvent type on neutral macrocycle facilitated transport of uranyl ions across supported liquid membranes using dicyclohexano 18-crown-6 as carrier. Radiochim. Acta, 1992, 57 185-194. 

Emory, S.F. Koga, Y. Azuma, N. Matsumoto, K. The effects of surfactant types and latex-particle feed concentration on membrane retention. Ultrapure Water 1993, 10 (2), 41 4. 

As demonstrated above, the edge tension is a sensitive parameter, which effectively characterizes the stability of pores in membranes. Compiling a database for the effect of various types of membrane inclusions will be useful for understanding the lifetime of pores in membranes with more complex compositions, which is important for achieving control over medical applications for drug and gene delivery in cells. 

Factors which influence the effectiveness of membrane separation systems are summarized. These factors include the complexation/decomplexation kinetics, membrane thickness, complex diffusivity, anion type, solvent type, and the use of ionic additives. 

Christensen JJ, Lamb LD, Izatt SR, Starr SE, Weed GC, Astin MS, Stitt BD, Izatt RM, Effect of anion type on rate of facihtated transport of cations across liquid membranes via neutral macrocychc carriers. J. Am. Chem. Soc. 1978 100, 3219-3220. 

Sharma, A., Goswami, A.N., Rawat, B.S. and Krishna, R. (1987). Effect of surfactant type on the selectivity for separation of 1-methyl naphthalene and dodecane using liquid membranes. J. Membr. Sci., 42, 19-30. 

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