Supported liquid membranes simple

In order to develop the liquid membrane techniques, i.e., emulsion Hquid membrane (ELM), supported liquid membrane (SLM), non-dispersive extraction in hollow fiber membrane (HFM), etc., for practical processes, it is necessary to generate data on equilibrium and kinetics of reactive extraction. Furthermore, a prior demonstration of the phenomena of facilitated transport in a simple liquid membrane system, the so-called bulk liquid membrane (BLM), is thought to be effective. Since discovery by Li [28], the liquid membrane technique has been extensively studied for the separation of metal ion, amino acid, and carboxyHc acid, etc., from dilute aqueous solutions [29]. 

Lezamiz, J. and J.A. Jonsson. 2007. Development of a simple hollow fibre supported liquid membrane extraction method to extract and preconcentrate dinitrophenols in environmental samples at ng L-1 level by liquid chromatography. J. Chromatogr. A 1152 226-233. 

A simple model for predicting the flux of CO2 through hollow fibre supported liquid membranes has been presented. It has been shown that radial geometry must be considered in order to accurately simulate the flux of the gas through the walls of a hollow fibre and that a flat sheet model is not able to capture this. However, because of... 

Vora-Adisak, N. and P. Varanusupakul. 2006. A simple supported liquid hollow fiber membrane microextraction for sample preparation of trihalomethanes in water samples. J. Chromatogr. A 1121 236-241. 

An innovative way of immobilizing a catalyst solution for a homogeneous catalytic reaction while simultaneously separating the produces) and reactant(s) was demonstrated by Kim and Datta [1991] who called it supported liquid-phase catalytic membrane reactor-sqiarator. The basic concept involves a membrane-catalyst-membrane composite as depicted in Figure 8.1 for a simple reaction ... 

MHS with pervaporation of water from LM (MHS-PV) is presented in Fig. 5.9. Contrary to the simple MHS with an agitated bulk liquid membrane, separated from the feed and strip solutions by flat hydrophobic or hydrophilic or ion-exchange membranes, the MHS-PV system exploits a Hquid membrane continuously flowing between the two flat cation-exchange and two pervaporation membranes. To couple the separation and pervaporation processes, the LM is simultaneously pumped through the MHS and PV modules. The pervaporation membranes are placed on stainless steel porous supports. Aqueous feed and strip solutions are intensively agitated. 

Bessarabov s devices use composite membranes consisting of a thin silicone rubber polymer layer coated onto a microporous poly(vinylidene fluoride) support layer. These membranes have high fluxes and minimal selectivities for the hydrocarbon gases, but the dense silicone layer provides a more positive barrier to bleed-through of liquid than do capillary effects with simple micro-porous membranes. 

A different type of a multiple membrane reactor system was proposed and modeled by Kim and Datta [5.68]. Their membrane reactor consists of liquid-phase catalytic layer supported on a porous matrix, which is sandwiched in between two different membranes. They considered a simple irreversible A- B reaction. The membrane, which is in contact... 

Langhendries et al [5.74] analyzed the liquid phase catalytic oxidation of cyclohexane in a PBMR, using a simple tank-in-series approximate model for the PBMR. In their -reactor the liquid hydrocarbon was fed in the tubeside, where a packed bed of a zeolite supported iron-pthalocyanine catalysts was placed. The oxidant (aqueous butyl-hydroperoxide) was fed in the shellside from were it was extracted continuously to the tubeside by a microporous membrane. The simulation results show that the PBMR is more efficient than a co-feed PBR in terms of conversion but only at low space times (shorter reactors). A significant enhancement of the organic peroxide efficiency, defined as the amount of oxidant used for the conversion of cyclohexane to the total oxidant converted, was also observed for the PBMR. It was explained to be the result of the controlled addition of the peroxide, which gives low and nearly uniform concentration along the reactor length. 

Chemical polymerization methods are also available for preparation of functionalized conducting polymers. Several techniques are shown in Table 9.1. The vapour/liquid interface chemical polymerization is recommended to obtain a thin and highly transparent membrane (film) (Table 9.1 (3)) [8]. On the other hand, utilizing an appropriate support which contains any kind of functional molecule, the functional molecule incorporating conducting polymer membrane, as well as a simple conducting polymer, is obtained by the methods illustrated in Table 9.1 (4). By these methods, it is possible to... 

The alternating electrostatic layer-by-layer adsorption of polyionic compounds has been proven to be a simple, yet elegant and versatile technique for preparation of films with controlled structure and uniform thickness in the nanometer range [1-3]. The method is also useful for the preparation of a new type of composite membrane with ultrathin separation layer, if cationic and anionic polyelectrolytes are alternately adsorbed on a porous support [4-11]. First attempts to use these membranes for separation of gases [4-6], liquid mixtures [7-10] and ions [8, 11] have already been reported. 

These materials are prepared by the covalent attachment of ionic hquids to the support surface or by simple deposition of the ionic liquid phases containing catalytically active species on the surface of the support (usually silica-based or polymeric materials including membranes). In various cases, the procedure involves the simple dissolution of a sulfonated phosphine-modified rhodium catalyst into a supported ionic liquid, while the alkene constitutes the organic phase. This method reduces the amount of ionic liquid and allows for a facUe and efficient separation of products from catalyst. In comparison to traditional biphasic systems, higher catalytic activity and lower metal leaching can be obtained by appropriately tuning the experimental conditions [35—41]. 

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