Industrial applications, liquid membrane technology

Some research groups worldwide are currently working on the application of membrane technology to the treatment of radioactive liquid wastes with different levels of activity, from low to high activity waste. Research is mainly focused on wastes from the nuclear industry. However, the nuclear industry is not the only source of radioactive wastes medical and research applications of radioisotopes also generate radioactive wastes. 

This chapter is concerned with the study of kinetics of solute transfer at free liquid/liquid boundaries. This process has found many applications in separation science [1] with developments in hydrornetallurgy (e.g. Cobalt/Nickel separation), nuclear fuel reprocessing, pharmaceutical industry and supported liquid membrane technology. indexTransfer kinetics... 

Adoption of liquid membrane technology in process industry is increasing. However there are several limitations to such applications of liquid membranes. The primary limitations are inadequate membrane durability and low net flux. In addition, liquid membranes are single-stage processes without cascading. 

Zhang XJ, Fan QJ, Zhang XT, and Liu ZF. New surfactant LMS-2 used for industrial application in liquid membrane separation. In Li NN, Strathmann H, eds. Separation Technology, New York United Engineering Trustees, 1988 215-226. 

Membrane technology used in water reclamation includes five major membrane types reverse osmosis, nanofiltration, ultrafiltration, microfiltration, and liquid membranes. These five types of membranes are discussed briefly, and examples of their applications in municipal and industrial wastewater reclamation is also described. 

Liquid impregnated (or immobilized) in the pores of a thin microporous sohd support is defined as a supported liquid membrane (SLM or ILM). The SLM may be fabricated in different geometries. Flat sheet SLM is useful for research, but the surface area to volume ratio is too low for industrial applications. Spiral-wound and hoUow-fiber SLMs have much higher surface areas of the LM modules (103 and 104 m /m, respectively [23]). The main problem of SLM technology is the stability the chemical stability of the carrier, the mechanical stability of porous support, etc. 

The author discusses application of ELM, SLM, and polymer inclusion membrane techniques in separation of metal ions (precious metals, Cu, Ni, Zn, Pb, Cd, Cr(VI), Pu, Am, etc.) and organic pollutants (phenols and its derivatives, carboxylic acids, antibiotics, etc.) from wastewaters using laboratory, pilot, and industrial scale modules. Effects of experimental variables upon the solute flux for the various types of liquid membranes are analyzed. The author discusses potential and commercial aspects of hquid membrane technology in wastewater treatment. 

In summary, this chapter presents the entire breadth of LM technology with the intention of furthering research and industrial applications. The various types of liquid membrane configurations are surveyed and the advantages and disadvantages of each type are described. The tutorial section of this chapter also discusses typical experimental techniques and a survey of theoretical approaches. 

The extraction capabilities of liquid membranes have been used successfully in many areas. Since 1968 efforts have been made for successfirl industrial application of hquid membrane technology. Emphasis has been on facilitated transport of LSMs. Some of the possible commercial apphcations are discussed below. 

Sensors Key technical problems involve materials and fabrication methods for both gas and liquid sensors opportunities for utilizing advanced microelectronics and membrane technologies are suggested for applications in environmental, industrial, and clinical systems, including in vivo monitoring of drug delivery systems. 

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