Emulsion-free liquid membrane

Carrier-facilitated transport of actinides across bulk, supported, and emulsion liquid membranes, as well as plasticized membranes and recently developed emulsion-free liquid membranes, are reviewed. The discussion includes the effects of important experimental variables upon the solute flux for various types of liquid membranes. Applications of liquid membranes in the recovery and removal of radiotoxic actinides from the nitric acid wastes generated during reprocessing of spent fuel by the PUREX process and wastes produced by other radiochemical operations are surveyed. 

Due to their high efficiency, ELMs would appear to be attractive alternatives to SLMs. However ELM systems often suffer from problems of low solubility and difficulties with de-emulsification. To overcome these problems, a new liquid membrane process, the emulsion free liquid membrane (EI M), was developed by Kumar ef al. (60). Application of this novel technique to hydrometallurgical processes is quite promising (67). Recent studies of separating heavy metals, such as Cr(VI) and Cu(II) from electroplating effluents, with an EFLM system indicate that the technique is very efficient and superior to other types of LMs. 

Figure 3. Schematic Diagram of an Emulsion Free Liquid Membrane (EFLM) Process.

Although not associated with the delivery of proteins, multiple emulsions or liquid membranes have been utilized for enzyme immobilization in place of solid-membrane methods or conventional methods (Scheper et al, 1987 May and Li, 1972). Multiple-emulsion systems have proved useful because there is no membrane fouling, they can be utilized in cell-free fermentation broths, and enzyme inhibitors can be excluded. 

Bulk Liquid Membrane. . . Emulsion Liquid Membrane. Supported Liquid Membrane Dispersion Free Extraction. ... 

Co-anion type and concentration are examined as parameters that can be varied to achieve various metal cation separations in macrocycle-facilitated emulsion liquid membranes. Membrane systems where the metal is present in the source phase as a complex anion or as a neutral complex (cation-anion(s)) are discussed. The experimental separations of Cd(II) from Zn(II) and/or Hg(II), Au(I) from Ag(I), and Au(III) from Pd(II) or Ag(I) are given to illustrate separation design using these membrane systems. The separations are discussed in terms of free energies of hydration, distribution coefficients, and equilibrium constants for the various interactions that occur. 

Interface surface, line, point and overall barriers-symmetries (surface — bilipid membrane cells, free bubbles of surfactants, Langmuir Blodgett films line — genes, liquid crystals, microtubules point — fullerenes, micro-emulsions overall — dry foams, polymer... 

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