Membranes, Hollow‐Fiber

Abstract

Hollow‐fiber membranes were invented in the 1960s. In the ensuing decades much research and development effort has transpired with the result that these fibers have become exceedingly important to industry, academia, and government in such fields as desalination of water, wastewater reclamation, medicine, agriculture, gas separation, and pervaporation. Commercial opportunities annually exceed several hundred million dollars. The hollow‐fiber membranes are usually the base technology within a significantly larger system.This article briefly discusses the history and theory of hollow‐fiber membrane technology. Methods of manufacture are reviewed together with processing techniques employed to enhance various aspects of performance. Hollow‐fiber membranes are composed of many different materials of construction. The generic compositions are cited and specific end use applications noted. Lastly, the work to date has identified many areas where future prospects for hollow‐fiber membranes are the brightest. A number of these future growth areas are discussed together with which industrial corporations are in the forefront of the new developments.

Porous stainless steel hollow fibers with shrinkage-controlled small radial dimensions

“…Hollow fiber membranes with small radial dimensions allow a very high surface-area-to-volume ratio, up to $10 4 m À1 , and can sustain large hydrostatic pressures. Polymeric hollow fiber membranes are widely used in various biomedical, medical and industrial applications [1,2]. These fibers are made in large quantities via the dry-wet spinning process, in which a polymer solution is pressed through a spinneret and coagulated in a bath of non-solvent [3][4][5][6].…”

“…These fibers are made in large quantities via the dry-wet spinning process, in which a polymer solution is pressed through a spinneret and coagulated in a bath of non-solvent [3][4][5][6]. As an example of how well established this process is, millions of membrane modules are produced annually for hemodialysis, each containing approximately 1 km of hollow fiber that has a distinct separation performance and no defects [1,2]. On average, these modules typically cost $10-20 each.…”

“…Here, we present a method that allows the preparation of stainless steel hollow fibers with an outer diameter that can be regulated down to $250 lm, comparable to that of typical polymeric hemodialysis and gas separation membranes [2]. The extraordinarily small radial dimensions are achieved by controlled shrinkage of the green fibers at temperatures exceeding the glass transition temperature.…”

Polyelectrolyte Complex Hollow Fiber Membranes Prepared via Aqueous Phase Separation

“…1 To better illustrate this point, as an example, a 0.04 m 3 membrane vessel can house 575 m 2 of the 90 μm-diameter hollow fibers and only 30 m 2 of the spiral-wound flat sheet membranes. 10 In addition, hollow fibers can be potted and hosted for mass packing, as opposed to the spiral-wound and tubular configurations that require additional hardware such as spacers and/or porous supports.…”

“…Since then, hollow fibers have been used for many applications; from the medical field , to water purification − and gas separation. , There are clear advantages to using the hollow fiber membrane geometry as compared to the flat sheet and tubular geometries, including their higher per unit volume productivity resulting from the high packing density . To better illustrate this point, as an example, a 0.04 m 3 membrane vessel can house 575 m 2 of the 90 μm-diameter hollow fibers and only 30 m 2 of the spiral-wound flat sheet membranes . In addition, hollow fibers can be potted and hosted for mass packing, as opposed to the spiral-wound and tubular configurations that require additional hardware such as spacers and/or porous supports.…”