Thin sheet supported liquid membranes

Zhu, C.Y. and Izatt, R.M., Macrocycle-mediated separation of Eu + from bivalent lanthanide cations in a modified thin-sheet-supported liquid membrane system. J. Membr. Sci., 1990, 50 319-324. 

C.Y. Zhu and R.M. Izatt, Macrocyclic-mediated separation of Eu2+ from trivalent lanthanide cations in a modified thin-sheet-supported liquid membrane system, J. Membr. Sci., 1990, 50, 319 P.R. Brown, J.L. Hallman, L.W. Whaley, D.H. Desai, M.J. Pugia and R.A. Bartsch, Competitive, proton-coupled, alkali metal cation transport across polymer-supported liquid membranes containing s>yn(decyl-dibenzo-16-crown-5-oxyacetic acid) Variation of the alkyl 2-nitrophenyl ether membrane, ibid., 1991, 56, 195. 

J.K. Kim, J.S. Kim, Y.G. Shul, K.W. Lee, and W.Z. Oh. Selective extraction of cesium ion with calix[4]arene crown ether through thin sheet supported liquid membranes. Journal of Membrane Science 187 3-11, 2001. 

Izatt, R.M. Lamb, J.D. Bruening, R.L. Comparison of bulk, emulsion, thin sheet supported, and hollow fiber supported liquid membranes in macrocycle-mediated cation separations, Sep. Sci. Technol. 23 (1988) 1645-1658. 

Much effort has been expended in attempting to use membranes for separations. Reverse osmosis membranes are used worldwide for water purification. These membranes are based on size selectivity depending on the pores used. They do not have the ability to selectively separate target species other than by size. Incorporation of carrier molecules into liquid membrane systems of various types has resulted in achievement of highly selective separations on a laboratory scale. Reviews of the extensive literature on the use of liquid membrane systems for carrier-mediated ion separations have been published [15-20]. A variety of liquid membranes has been studied including bulk (BLM), emulsion (ELM), thin sheet supported (TSSLM), hollow fiber supported (HFSLM), and two module hollow fiber supported (TMHFSLM) types. Of these liquid membranes, only the ELM and TMHFSLM types are likely to be commercialized. Inadequacies of the remaining... 

Liquid impregnated (or immobilized) in the pores of a thin microporous sohd support is defined as a supported liquid membrane (SLM or ILM). The SLM may be fabricated in different geometries. Flat sheet SLM is useful for research, but the surface area to volume ratio is too low for industrial applications. Spiral-wound and hoUow-fiber SLMs have much higher surface areas of the LM modules (103 and 104 m /m, respectively [23]). The main problem of SLM technology is the stability the chemical stability of the carrier, the mechanical stability of porous support, etc. 

We have made use of the cation-selective properties of macrocycles to design liquid membrane [6], supported liquid membrane [6], and macrocycle-bonded silica gel [7] systems for specific cation separations. The selective transport of Ag [8, 9], Pb " [8], K" [10] and Li [11] was observed in a bulk liquid membrane system using various macrocyclic ligands. In the supported liquid membrane (thin sheet and hollow fiber) systems, selective and predicted separations of Na /K , Cd " / Hg ", and others have been achieved [12, 13],... 

The customary type of a liquid membrane electrode is a design in which the sensitive membrane is composed of a water-immiscible organic solvent containing the ion of interest in the form of ion associate. The membrane is interposed between a standard (internal) and a test (external) ion solution.""" In early types of liquid membrane electrodes, an organic phase as a membrane is placed between two aqueous phases in bulk or with the support of a thin, porous cellulose sheet, sintered glass, or similar lamellas. Nitrobenzene is the popular membrane solvent other organic solvents are also applied such as o-nitrotoluene, 4-ethylnitrobenzene, 4-nitro-m-xylene, and p-nitrocoumarin. 

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