Liquid membranes integrity

In membrane extraction, the treated solution and the extractant/solvent are separated from each other by means of a solid or liquid membrane. The technique is applied primarily in three areas wastewater treatment (e.g., removal of pollutants or recovery of trace components), biotechnology (e.g., removal of products from fermentation broths or separation of enantiomers), and analytical chemistry (e.g., online monitoring of pollutant concentrations in wastewater). Figure 18a shows schematically an industrial hollow fiber-based pertraction unit for water treatment, according to the TNO technology (263). The unit can be integrated with a him evaporator to enable the release of pollutants in pure form (Figure 18b). 

Supported liquid membrane (SLM) Aqueous solution An immiscible immobilized liquid membrane containing specific metal ion carriers Divalent metal ions Integrative field sampling, preconcentration of trace elements, mimicking biological membranes Days 74... 

Brumbaugh, W.G., J.D. Petty, J.N. Huckins, and S.E. Manahan. 2002. Stabilized liquid membrane device (SLMD) for the passive, integrative sampling of labile metals in water. Water Air Soil Pollut. 133 109-119. 

Dimitrov, K., Metcheva, D. and Boyadzhiev, L. (2005) Integrated processes of extraction and liquid membrane isolation of atropine from Atropa belladonna roots. Separation and Purification Technology, 46, 41. 

Solvent extraction of penicillin from fermentation broths has been well documented in the literature. Penicillin G and penicillin V can be efficiently extracted with amyl acetate or butyl acetate at pH 2.5-3.0 and at 0° to 3°C.33 Schiigerl1 systematically reviewed solvent extraction of different forms of penicillin from fermentation broths. Figure 1 shows an integrated process for the extraction of penicillin G from clarified broth of Penicillium chryso-genurn fermentation.1 Penicillin G is converted to 6-amino penicillanic acid and phenylacetic acid at pH 8 in a 10 L Kiihni extractor by penicillin G-amidase immobilized in an emulsion liquid membrane. The 6-amino penicillanic acid is subsequently converted to ampicillin at pH 6 and the enzyme is recycled. 

Knutsson M, Nilve G, Mathiasson L, and Jdnsson JA. Supported liquid membrane technique for time-integrating field sampling of acid herbicides at sub part per billion level in natural waters. J. Agric. Food Chem. 1992 40 2413-2417. 

Wodzki R and Szczepanski P. Integrated hybrid liquid membrane systems—membrane extraction and pertraction coupled to a pervaporation process. J Mem Sci, 2002 197(1-2) 297-308. 

With the advancement of membrane technologies and engineering in the integration of MF, UF, NF, and RO membrane systems, and possibly a liquid membrane system, wastewater reclamation can provide high quality water for underground water replenishment and direct household nonpotable use, and source water for ultra-pure water applications. Membrane technology provides several advantages over conventional treatment processes ... 

N/m was applied across the membrane. The membrane was used at a temperature from 363 to 403 K. To prevent evaporative loss of the liquid from the membrane, the relative humidity of the gases adjacent to the membrane was controlled in the range of 60 to 90%. Kimura, Matson, and Ward (16) discussed the immobilization of bicarbonate solutions for CO2 and H2S facilitated transport. They indicated that a major problem was maintaining the integrity of the supported liquid membrane when large pressure differences were imposed across the membrane. 

An attempt to unify the mass transport phenomena of liquid membrane separation underlying the basic LM configurations was presented in this chapter. The basic theory was developed in a simple physical-chemical-mathematical form and applied to the principal techniques in such a way to obtain comparable methods. Of course it is prehminary work once we start forging links between different methods there wiU be spiUover to further possibilities of integration. 

M., ViUora, G. (2007). Integrated reaction/separation processes for the kinetic resolution of rac-l-phenylethanol using supported liquid membranes based on ionic liquids. Chem. Eng. Process., 46, 818-24. 

Promising results are shown by recently developed integrated SLM-ELM [84, 85] systems. These techniques are known as supported liquid membrane with strip dispersion (SLMSD), pseudo-emulsion-based hollow fiber strip dispersion (PEHFSD), emulsion pertraction technology (EPP), and strip dispersion hybrid Hquid membrane (SDHLM). AH techniques are the same the organic phase (carrier, dissolved in diluent) and back extraction aqueous phase are emulsified before injection into the module and can be separated at the module outlet. The difference is only in the type of the SLM contactors hoUow fiber or flat sheet and in the Hquid membrane (carrier) composition. These techniques have been successfuUy demonstrated for the removal and recovery of metals from wastewaters. Nevertheless, the techniques stiU need to be tested in specific apphcations to evaluate the suitabUity of the technology for commercial use. 

Hernindez-Femandez FJ, de los Rios AP, Tomis-Alonso F, G6mez D, Vfllora G (2007) Kinetic resolution of 1-phenylethanol integrated with separation of substrates and products by a supported ionic liquid membrane. J Chem Technol Biotechnol 82 190-195... 

Kimura et al. (1 ) noted that a major problem was maintaining the Integrity of the supported liquid membrane when large pressure differences were Imposed across the membrane. 

Compressed air supply system Rotary screw air compressors supply air at 9 bar g for air-assisted liquid backwash to remove particulates from the membrane surface. It also supplies air for the Membrane Integrity Test as well as various plant instruments and controls. 

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