Carrier facilitated transport supported liquid membranes

Olefins. Facilitated transport of olefins has also been reported in the literature. LeBlanc et al. (2 ) studied ethylene transport using a silver Ion carrier in an Ion exchange membrane. Hughes et al. (23) presented the results of a bench and pilot scale study of ethylene and propylene transport using a silver ion Immobilized In anisotropic, porous hollow fiber membranes. This work is very significant because it is the first report facilitated transport membranes used on a commercial scale. Teremoto et al. (24) also studied ethylene transport with a silver ion carrier in a supported liquid membrane. They found a selectivity for ethylene over ethane of approximately 1000 when the silver nitrate concentration was 4 mol/ dm. ... 

The discussion so far implies that membrane materials are organic polymers, and in fact most membranes used commercially are polymer-based. However, in recent years, interest in membranes made of less conventional materials has increased. Ceramic membranes, a special class of microporous membranes, are being used in ultrafiltration and microfiltration applications for which solvent resistance and thermal stability are required. Dense, metal membranes, particularly palladium membranes, are being considered for the separation of hydrogen from gas mixtures, and supported liquid films are being developed for carrier-facilitated transport processes. 

The typical concentration profile of solute in an SLM system with quaternary ammonium salt as carrier is schematically shown in Fig. 6. To model the facilitated transport within a supported liquid membrane [58,59], the following assumptions are usually made ... 

Danesi, P.R. Horwitz, E.P. Rickert, P.G. Rate and mechanism of facilitated americium(III) transport through a supported liquid membrane containing a bifunctional organophosphorous mobile carrier, J. Phys. Chem. 87 (1983) 4708-4715. 

Paugam, M.F. and Buffle, J. (1998) Comparison of carrier-facilitated copper (II) ion transport mechanisms in a supported liquid membrane and in a plasticized cellulose triacetate membrane. Journal of Membrane Science, 147, 207. 

Carrier-facilitated transport is used successfully to extract various organic and inorganic substances from a feed mixture in liquid membranes. Liquid membranes are employed as bulk liquid membranes, emulsion liquid membranes, and supported liquid membranes. 

Teramoto M, Matsuyama H, Nakai K, Uesaka T, and Ohnishi N. Eacilitated uphill transport of eicosapentaenoic acid ethyl ester through bulk and supported liquid membranes containing silver nitrate as carrier A new type of uphill transport. J Mem Sci, 1994 91(1-2) 209-213. Teramoto M, Matsuyama H, and Ohnishi N. Selective facilitated transport of benzene across supported and flowing liquid membranes containing silver nitrate as a carrier. J Mem Sci, 1990 50 269-278. 

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. 

Sastre, A., Madi, M., Cortina, J.L. and. Mira lies, N. (1998). ModeUing of mass transfer in facilitated supported liquid membrane transport of gold(III) using phospholene derivatives as carriers. J. Membr. Sci., 139, 57-65. 

Facilitated or carrier-mediated transport is a coupled transport process that combines a (chemical) coupling reaction with a diffusion process. The solute has first to react with the carrier to fonn a solute-carrier complex, which then diffuses through the membrane to finally release the solute at the permeate side. The overall process can be considered as a passive transport since the solute molecule is transported from a high to a low chemical potential. In the case of polymeric membranes the carrier can be chemically or physically bound to the solid matrix (Jixed carrier system), whereby the solute hops from one site to the other. Mobile carrier molecules have been incorporated in liquid membranes, which consist of a solid polymer matrix (support) and a liquid phase containing the carrier [2, 8], see Fig. 7.1. The state of the art of supported liquid membranes for gas separations will be discussed in detail in this chapter. 

The use of facilitated transport membranes for gas separation was first introduced by Ward and Robb [54] by impregnating the pores of a microporous support with a carrier solution, and a separation factor of 1500 was reported for CO2/O2. These membranes, or supported liquid membranes (SLMs), are discussed by several, and initially very good separation properties are observed [55-58]. They are however known to have serious degradation problems like loss of carrier solution due to evaporation or entrainment with the gas stream, and the complexing agent (carrier) can be deactivated. These problems have restricted further development... 

Panja, S., Mohapatra, P.K., Tripathi, S.C., Manchanda, V.K., Facilitated transport of uranium(VI) across supported liquid membranes containing T2EHDGA as the carrier extractant, J. Hazard. Mater. 188, 281, 2011. 

Mitiche, L., Tingry, S., Seta, P., and Sahmoime, A. 2008. Facilitated transport of copper(II) across supported liquid membrane and polymeric plasticized membrane containing 3-phenyl-4-benzoylisoxazol-5-one as carrier. Journal of Membrane Science 325 605-611. 

F.J. Alguacil, H. Tayibi, Carrier-facilitated transport of Cd(II) from a high-salinity chloride medium across a supported liquid membrane containing Cyanex 923 in Solvesso 100, Desalination 180 (2005) 181-187. 

Biswas, S., Pathak, P.N. Roy, S.B. (2012) Carrier facilitated transport of uranium across supported liquid membrane using dinonyl phenyl phosphoric acid and its mixture wifli neutral donors. Desalination, 290, 74-82. 

Joshi, J.M., Pathak, P.N., Pandey, A.K. Manchanda, VK. (2009) Study on synergistic carriers facilitated transport of uranium(VI) and europium(III) across supported liquid membrane from phosphoric acid media. Hydrometallurgy, 96 (1-2), 117-122. 

In this study, experiments on the simultaneous permeation of CO2 and CH4 through aqueous MEA, DEA and ethylenediamine hydrochloride (EDAHCl) membranes are performed and the permeation rates of CO2 are quantitatively discussed on the basis of the approximate solution of facilitated transport (77). A method is also proposed for applying the facilitated transport theory developed for a liquid membrane consisting of a liquid membrane phase alone to the analysis of facilitated transport through a supported liquid membrane prepared by impregnating a microporous polymer support having tortuous pore structure with a carrier solution. 

Facilitated transport membranes for gas separation were prepared conventionally by impregnating the pores of microporous supports with the carrier solutions. This type of membrane is a typical mobile carrier membrane and is known as a supported liquid membrane (SLM) or immobilized liquid membrane (ILM). 

Figures 12 and 13 show the effects of CO2 feed partial pressures, pc02 on Rc02 and a for dry and water-containing membranes, respectively. In both cases, as the CO2 feed pressure increased, Rco2 decreased while Rn2 was nearly constant. The decrease in Rc02 observed for both dry and water-containing membranes suggests that CO2 permeates by the carrier transport mechanism in both conditions. However, the mechanism may be different for the two cases. In the dry membranes, the facilitated transport of CO2 is expected to be attributable to the weak acid-base interaction between CO2 and amine moiety, as suggested by Yoshikawa et al. (27). Therefore, the dry membrane is a fixed carrier membrane. On the other hand, tertiaiy amine groups in the wet membrane are considered to act as catalyst for the hydration of CO2 as in the case of triethanolamine in a supported liquid membrane (28). The mechanism is schematically represented as follows ...

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. 

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... 

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