Single hollow-fiber membrane

Pratt KF and Pawliszyn J. Water monitoring system based on gas extraction with a single hollow fiber membrane and gas chromatographic cryotrapping. Anal. Chem. 1992 64 2107-2110. 

The above-mentioned operating modes of the hollow fiber membrane module for oxygen production are shown in Figure 18.6 where the flows in a single hollow fiber membrane are depicted. In practical operation, the air feed is generally introduced into the shell side while the oxygen product flows counter-currently in the lumen side of the hollow fiber membranes. 

Consider the single hollow fiber membrane as shown in Figure F.2. 

In the past decade, several novel solvent-based microextraction techniques have been developed and applied to environmental and biological analysis. Notable approaches are single-drop microextraction,147 small volume extraction in levitated drops,148 flow injection extraction,149 150 and microporous membrane- or supported liquid membrane-based two- or three-phase microextraction.125 151-153 The two- and three-phase microextraction techniques utilizing supported liquid membranes deposited in the pores of hollow fiber membranes are the most explored for analytes of wide ranging polarities in biomatrices. This discussion will be limited to these protocols. 

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. 

Steady state models of membrane bioreactors utilizing a multi-enzyme system, which in addition to the main reaction promotes the simultaneous regeneration of the co-factor (for further discussion see Chapter 4) have been developed by different groups in Japan [5.109, 5.110]. Several of these studies have also considered the effect of backmixing [5.111, 5.112]. A model of an enzymatic hollow fiber membrane bioreactor with a single enzyme, which utilizes two different substrates (reaction 5.42) has been developed recently by Salzman et al [5.113]. 

Estimate convective mass-transfer coefficients for the following situations (a) flow paralell to a flat surface, (b) flow past a single sphere, (c) flow normal to a single cylinder, (d) turbulent flow in circular pipes, (e) flow through packed and fluidized beds, and (f) flow through the shell side of a hollow-fiber membrane module. 

The BS Amultilayer-adsorbed porous hollow-fiber membrane was mounted ona single hollow-fiber module, as showninFigure 13. The module size was 5 mm in inner diameter and 40 mm in effective length. The module was incorporated into a liquid chromatography system. A... 

Membrane Systems and Experiments. The transport of nitric acid through a supported liquid membrane (SLM) containing trilaurylamine (TLA) as carrier was studied using a single hollow fiber module. 

Gao L, Jonsson JA. Determination of melamine in fresh milk with single hollow fiber supported liquid membrane extraction based on ion pair mechanism combined with high performance liqnid chromatography. Anal Lett 2012 45 2310-2323. 

Reverse osmosis unit, including membrane, pressure vessels, single pass system with either spiral wound or hollow fiber membranes. FOB cost 220000 at membrane area = 1600 m with n = 0.47 for the range 12-1600 and n= 0.85 for the range 1600-3 000000. L-i-M = 1.2-3.2 with large values for smaller size. 

Dual layer hollow fiber membranes have become increasingly attractive due to which they can be fabricated in a single step using the non-solvent induced phase inversion method. A good lamination between the two layers as well as a regular morphology are critical to get a functional hollow fiber membrane [80]. 

LLE, liquid-liquid extraction MAE, microwave-assisted extraction SEE, solid-phase extraction SPME, solid-phase microextraction LPME, liquid-phase microextraction SOME, single-drop microextraction D-LLLME, dynamic liquid-liquid-liquid microextraction SEE, supercritical fluid extraction MIP, molecularly imprinted polymers sorbent SPMD, device for semipermeable membrane extraction PDMS, polydimethylsiloxane coated fiber PA, polyacrylate coated fiber CW-DMS, Carbowax-divinylbenzene fiber PDMS-DVB, polydimethylsiloxane divinylbenzene fiber CAR-PDMS, Carboxen-polydimethylsiloxane coated fiber DVB-CAR-PDMS, divinylbenzene Carboxen-polydimethylsiloxane coated fiber CW-TPR, Carbowax-template resin HS-SPME, headspace solid-phase microextraction MA-HS-SPME, microwave-assisted headspace-solid-phase microextraction HEM, porous hollow fiber membrane PEl-PPP, polydydroxylated polyparaphenylene. 

Jiang LY, Chung TS, Cao C, Huang Z, Kulprathipanja S. Fundamental understanding of nano-sized zeolite distribution in the formation of the mixed-matrix single and dual-layer asymmetric hollow fiber membranes. J Membr Sci 2005 252(l-2) 89-100. 

Figure 9.17 illustrates the general schematic of the membrane unit used in permeation measurements. Experimental permeation runs were performed with CO2 and N2 in a composite PES/PI (polyethersulfone Sumikaexcel/polyimide Matrimid 5218) hollow-fiber membrane. The single-component permeances were measured using a standard variable-pressure method and the binary ratios converted into the corresponding ideal selectivities. A specified feed pressure was applied to the upstream shell-side, while the permeate side was initially under vacuum. The permeation rates were calculated from the pressure increase as a function of time, in a downstream calibrated volume. The permeation stopped when equalization between pressures on both sides of the membrane was achieved. The main physical properties of the membrane are listed in Table 9.2. 

To overcome the problems of cellulose acetate membranes, many synthetic polymeric materials for reverse osmosis were proposed, but except for one material, none of them proved successful. The only one material, which could remain on the market, was the linear aromatic polyamide with pendant sulfonic acid groups, as shown in Figure 1.2. This material was proposed by DuPont, which fabricated very fine hollow fiber membranes the modules of this membrane were designated B-9 and B-10. They have a high rejection performance, which can be used for single-stage seawater desalination. They were widely used for mainly seawater or brackish water desalination and recovery of valuable materials such as electric deposition paints, until DuPont withdrew them from the market in 2001. 

Toyobo s newest innovative RO module builds on the proven reliability of the HM-type module. The new technology is based on both open-ended (BOE) hollow-fiber membrane stmctures versus single open-ended hoUow-fiber membrane stractures. The... 

Both Open-Ended (BOE) Hollow-Fiber Membrane Single Open-Ended Hollow-Fiber Membrane Figure 2.18 Comparison of both open-ended (BOE) vs. single open-ended hoUow-fiber membrane. 

Kumano, A., Fujiwara, N., Nishida, M., and Sekino, M. (2003). A single-stage RO seawater desahnation process at higher recovery with improved hollow fiber membrane modules. In Proceedings of IDA World Congress on Desalination and Water Reuse. IDA, Atrantis Resort, Paradise Island, Bahamas. 

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