Metals through supported liquid membranes

Danesi, P.R. and Reichley-Yinger, L., Origin and significance of the deviations from a pseudo first order rate law in the coupled transport of metal species through supported liquid membrane. J. Membr. Sci., 1986, 29 195-206. 

The ability of calixarenes to bind large metal ions with high kinetic stability is important in the search for complexants for radionuclides such as Cs (ti/2 = 30.2 yr) and Sr (ti/2 = 65 d) from the reprocessing of exhausted nuclear fuel. There has been considerable interest in caesium-complexed calix[4]-bis-crowns as selective Cs-carriers. Transport isotherms of trace level Cs through supported liquid membranes containing calix[4]-bis-crowns have been determined as a function of the ionic concentration of the aqueous feeder solutions, and l,3-calix[4]-bis-o-benzo-crown-6 appears to be much more efficient in decontamination than mixtures of crown ethers and acidic exchangers, especially in highly acidic media. " ... 

Ata, O.N. (2007) Mathematical modelling of unsteady-state transport of metal ions through supported liquid membrane. Hydrometallurgy, 87,148-156. 

Reusch and Cussler were the first to describe crown ether-mediated transport of alkali metal cations through supported liquid membranes as ion pairs and derived for the initial flux Equation 11. 

Facilitated Transport of Alkali Metal Cations Through Supported Liquid Membranes with Fatty Acids... 

Acyclic oligoamides, 167-168,170/ Advancing front model, description, 116 Alkali metal cation facilitated transport through supported liquid membranes with fatty acids electrogenic processes, 79-81 electroneutral transport, 76-80 experimental description, 77 kinetics, 81-85... 

Amide-containing dibenzo-16-crown-5 compounds, transport of metal perchlorates, 161-165 Amine(s) as carriers, carbon dioxide facilitated transport through functional membranes prepared by plasma graft polymerization, 252-268 Amine solutions, carbon dioxide facilitated transport through supported liquid membranes, 239-250 Amino acid derivatives, use as heavy metal ion carriers, 175-179... 

The use of 13a in the extraction process or in the transport through supported liquid membranes (SLMs) allows to recover more than 98% of the cesium cation present in solution, making this derivative extremely attractive for declassification of nuclear wastes. Ligand 13a was dso used for the selective detection of cesium in ISEs and ISFETs with very high selectivity and low detection limit. Very recently, we anchored calix[4]arene-crown-5 and -crown-6 derivatives on silica-gel via hydrosilanization and we were able to separate by chromatography potassium or cesium fi"om other alkali metal ions with high efficiency. ... 

Abstract. The synthesis of 1,2- and l,3-calix[4]-Z w-crowns, double calix[4]arenes and double calixcrowns have been shown to depend on the reaction conditions (nature of the base, structure of the ditosylates, and the stoichiometry of the reactants). The 1,3-altemate conformation of the 1,3-calix[4]- w-crowns was shown to be favourable to the selective complexation of cesium cation. The observed Na /Cs selectivity was exploited in separation processes using them as carriers in transport through supported liquid membranes (SLMs). The best Na "/Cs selectivity (1/45 000) was observed for the naphthyl derivative 7. Calix(aza)crowns and 1,3-calix[4]-/ w-(aza)-crowns were also produced through the preliminary formation of the Schiff base-calixarenes, which were further hydrogenated. The syntheses consisted of the 1,3-selective alkylation of calixarenes followed by cyclization into a 1,3-bridged calixarene or by the direct 1,3-capping of the calixarene with appropriate ditosylates. Soft metal complexation by these ligands is also presented. 

Dense inorganic or metallic membranes for gas separation are usually ion-conducting materials, while membranes with carriers are polymers or supported liquid membranes (SLM). For transport through these materials, different flux equations should be applied. Figure 4.2 sums up and generalizes the various types of transport, which may take place in gas-separation membranes [21]. 

Danesi, P.R. and Cianetti, C., Permeation of metal ions through a series of two complementary supported liquid membranes. J. Memhr. ScL, 1984, 20 201-213. 

Bromberg L, Levin G, Kedem O, Transport of metals through gelled supported liquid membranes containing carrier. J. Membr. Sci. 1992 71, 41. 

P. R Danesi, A simplified model for the coupled transport of metal ions through hollow-fiber supported liquid membranes, J. Membrane Sci., 20, 231-248 (1984). 

S. Armalis, I. Kriksciuniene, E. Kubiliene, N.K. Djane, K. Ndungu, L. Mathiasson, Stripping analysis of trace metals at flow-through reticulated vitreous carbon electrode after the preconcentration by supported liquid membrane technique, Int. J. Environ. Anal. Chem. 74 (1999) 233—242. 

Polymer inclusion membranes (PIMs) are a relatively novel type of self-supporting liquid membranes for the extraction and separation of metallic and non-metallic ionic species and small organic molecules from dilute aqueous solutions. PIMs entrap a solute-selective extraction reagent, often referred to as the carrier, in a base polymer matrix, which consists of a base polymer and in some cases may contain plasticizers and chemical modifiers. When the PIM is placed in contact with the dilute aqueous solution, the extractant reactively couples with the solute of interest and transfers it into or through the membrane. 

Kubota F, Shimobori Y, Koyanagi Y, Shimojo K, Kamiya N, Goto M (2010) Uphill transport of rare-earth metals through a highly stable supported liquid membrane based on an ionic liquid. Anal Sci 26 289-290... 

In this chapter membrane preparation techniques are organized by membrane structure isotropic membranes, anisotropic membranes, ceramic and metal membranes, and liquid membranes. Isotropic membranes have a uniform composition and structure throughout such membranes can be porous or dense. Anisotropic (or asymmetric) membranes, on the other hand, consist of a number of layers each with different structures and permeabilities. A typical anisotropic membrane has a relatively dense, thin surface layer supported on an open, much thicker micro-porous substrate. The surface layer performs the separation and is the principal barrier to flow through the membrane. The open support layer provides mechanical strength. Ceramic and metal membranes can be either isotropic or anisotropic. 

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