Hollow fiber membrane material

This chapter will mainly cover extraction systems with liquid membrane phases and trapping in the acceptor. Two- and three-phase systems are compared, as well as dynamic and static systems and flat versus hollow-fiber membrane materials. These types of systems have been successfully applied to a number of analyte and sample types and can be important alternatives to more older approaches to sample preparation. 

Inner Diameter Outer Diameter Number of Lumina Diameter Length Area per Unit Volume (cm" ) Hollow Fiber Membrane Material Source/ Supplier... 

The principle of a three-phase membrane extraction is illustrated in Figure 1.28. An organic solvent is immobilized in the pores of a porous polymeric support consisting of a flat filter disc or a hollow fiber-shaped material. This supported liquid membrane (SLM) is formed by treating the support material with an organic solvent that diffuses into its pores. The SLM separates an aqueous... 

FIGURE 1.33 Top left membrane unit with 1 mL channel volume (A = inert material B = membrane) Top right membrane unit with 10 flh channel volume. Bottom hollow fiber membrane unit with 1.3 /rL acceptor channel (lumen) volume.151 (Reproduced with permission from IUPAC.)... 

Hollow fiber membrane(s), 70 766 76 1-31 additional types of, 76 24 advantages of, 76 3 categories of, 76 2-3 in desalination, 76 22 development of, 76 1 extractors, 70 787 fiber treatment for, 76 12-18 future prospects for, 76 26-28 glass and inorganic, 76 23-24 handling and unit assembly of, 76 15-18 interpenetrated wall matrix in, 76 15 low pressure, 76 24-26 macrovoids in, 76 12 materials associated with, 76 18-24 melt spinning of, 76 9-10... 

Widjojo, N., Chung, T.S., and Kulprathipanja, S. (2008) The fabrication of hollow fiber membranes with doublelayer mixed-matrix materials for gas separation. J. Memhr. Sci., 325 (1), 326-335. 

Removing Small Molecular Weight Contaminants. Ultrafiltration in hollow fiber membrane cartridges was the best method found to remove small molecular weight materials (75). It also served to concentrate the enzymes and change the buffer (via diafiltration) to that required for the next purification step. A 10,000 mwt... 

HOLLOW-FIBER MEMBRANES. A hollow-fiher membrane is a capillary having an inside diameter of - inn and an outside diameter < I mm and whose wall functions as a semipermeahlc membrane. The fibers can he employed singly or grouped into a bundle which may contain tens of thousands of fibers and up to several million libers as in reverse osmosis (Fig. 11. In most eases, hollow fibers are used as cylindrical membranes that permit selective exchange of materials across (heir walls. However, they can also he used as containers to effect the controlled release of a specific material, or as reactors to chemically modify a permeate as il diffuses through a chemically activated hollow-liher wall. e g., loaded with immobilized enzyme. 

US 5- 10/g. Single-layer hollow fiber membranes contain 10-20 g of polymer per square meter of membrane, for a material cost alone of US 50-200/m2. Thus, using a composite structure consisting of a relatively inexpensive core polymer material coated with a thin layer of the expensive selective polymer reduces the overall membrane material cost significantly. 

Clark H, Barbari TA, Stump K, Rao G. Histologic evaluation of the inflammatory response around implanted hollow fiber membranes, journal of Biomedical Materials Research 2000, 52, 183-192. 

Salts rejected by the membrane stay in the concentrating stream but are continuously disposed from the membrane module by fresh feed to maintain the separation. Continuous removal of the permeate product enables the production of freshwater. RO membrane-building materials are usually polymers, such as cellulose acetates, polyamides or polyimides. The membranes are semipermeable, made of thin 30-200 nanometer thick layers adhering to a thicker porous support layer. Several types exist, such as symmetric, asymmetric, and thin-film composite membranes, depending on the membrane structure. They are usually built as envelopes made of pairs of long sheets separated by spacers, and are spirally wound around the product tube. In some cases, tubular, capillary, and even hollow-fiber membranes are used. 

Pabby, A.K. and Sastre, A.M. (2006) Hollow-fiber membrane based separation technology performance and design perspectives, in Solvent Extraction and Liquid Membranes Fundamental and Application in New Materials (eds Cortina and Aguilar), Marcel Dekker, New York. 

With respect to carbon membranes, the molecular sieving carbon membranes, produced as unsupported flat, capillary tubes, or hollow fibers membranes, and supported membranes on a macropo-rous material are good in terms of separation properties as well as reasonable flux and stabilities, but are not yet commercially available at a sufficiently large scale, because of brittleness and cost among other drawbacks [3,6],... 

Extraction of phenol from aqueous solution using hollow fiber membrane contactor was first investigated in Ref. [100]. However, the membrane used was not completely microporous. Instead, it was a dialysis-type membrane. A commercial plant to separate phenol from hydrocarbon fraction using microporous membrane contactors was reported in Ref. [101]. Soda lye was used to react with the phenol transferred from the feed phase to create and maintain the driving force for separation. This industrial-scale application enabled the processing of hydrocarbon fraction to a full-value raw material for phenol and acetone synthesis. 

Skiens WE, Lipps BJ, Clark ME, and McLain EA, Hollow fiber membrane oxygenator. Journal of Biomedical Materials Research Symposium, 1971, 1, 135-148. 

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