Removal using emulsion liquid membranes

Acetic acid, removal using emulsion liquid membranes, 215 Acrylic acid, use in plasma graft polymerization, 254-268 Acrylic acid grafted membranes, use in facilitated transport, 250-264 Actinide, separation from reprocessing wastes with liquid membranes, 391-406 Acyclic ligands, 167,168/... 

Datta S, Bhattacharya PK, Verma N (2003) Removal of aniline from aqueous solution in a mixed flow reactor using emulsion liquid membrane. J Membr Sci 2269(1-2) 185-201... 

Gleason KJ, Yu J, Bunge AL, and Wright JD. Removal of selenium from contaminated waters using emulsion liquid membranes. In Bartsch RA, Way JD, eds. Chemical Separations with Liquid Membranes, Washington, DC American Chemical Society, ACS symposium series 642, 1996 342-360. 

Gurel, L., Alias, L. and Buyukgungor, H. (2005). Removal of lead from wastewater using emulsion liquid membrane technique. Environ. Eng. Sci., 22, 411-20. 

Removal of Selenium from Contaminated Waters Using Emulsion Liquid Membranes... 

There is an ever increasing interest in the use of liquid membranes for performing chemical separations. Emulsion liquid membrane (ELM) systems in which the targeted chemical species in an aqueous solution is extracted with a multicomponent emulsion have a variety of applications. These include isolation and concentration of valued or harmful substances in industrial chemistry, separation of substances for determination in analytical chemistry, separation of pollutants in environmental remediation, and detoxification of biological fluids by removal of harmful substances of exogenic and endogenic origins (7). 

Experimental Measurements. Removal of arsenic firom metallurgical wastewater by emulsion liquid membrane was studied experimentally (9). One set of experimental data is used here to verify the mathematical model. The experiment on emulsion liquid membrane removal of arsenic was conducted as follows. 

Much effort has been expended in our labs over the last few years investigating the use of emulsion liquid membranes to carry out such wastewater treatment schemes with a special focus on the removal of mercury ions from water. Both coarse or macroemulsions as well as microemulsions were studied and compared. The advantage of emulsion liquid membrane extraction is the large surface area available for mass transfer which results in fast separations. Because the volume ratio of the feed to internal receiving phase is high, the separated metal is concentrated by factors as high as... 

The emulsion liquid membrane (ELM) process was shown to be an effective method for pre-concentrating dilute selenium streams, such as those found in the wastewaters from petroleum refineries. By concentrating the selenium, the ELM process can greatly reduce the operating costs and capital costs of the coagulation/coprecipitation processes presently used to remove selenium. 

Ultrasound-assisted emulsification in aqueous samples is the basis for the so-called liquid membrane process (LMP). This has been used mostly for the concentration and separation of metallic elements or other species such as weak acids and bases, hydrocarbons, gas mixtures and biologically important compounds such as amino acids [61-64]. LMP has aroused much interest as an alternative to conventional LLE. An LMP involves the previous preparation of the emulsion and its addition to the aqueous liquid sample. In this way, the continuous phase acts as a membrane between both the aqueous phases viz. those constituting the droplets and the sample). The separation principle is the diffusion of the target analytes from the sample to the droplets of the dispersed phase through the continuous phase. In comparison to conventional LLE, the emulsion-based method always affords easier, faster extraction and separation of the extract — which is sometimes mandatory in order to remove interferences from the organic solvents prior to detection. The formation and destruction of o/w or w/o emulsions by sonication have proved an effective method for extracting target species. 

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. 

Phenol and Ammonia Recovery. Finally, the closely related passive and fa-cilitated-transport processes for phenol and ammonia recovery should be mentioned. In these processes, dilute phenol or ammonia feed solutions are contacted with a liquid membrane in which they are freely soluble. They dissolve in the membrane, diffusing to the product side where they are removed by neutralizing with a base (in the case of phenol) or an acid (in the case of ammonia). Although the transport mechanism does not involve a carrier and these are, therefore, passive transport processes, the actual process is quite similar, and Li et al25 published the details of these separations using emulsion membrane technique. 

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