Asymmetric membrane hollow fiber

Okamoto, K.,S. Kawamura, M. Yoshino, H. Kita, Y. Hirayama, N. Tanihara, and Y. Kusuki, Olefin/ paraffin separation through carbonized membranes derived from an asymmetric polyimide hollow fiber membrane, Ind. Eng. Chem. Res., 38, 4424,1999. 

N. Tanihara, H. Shimazaki, Y. Hirayama, N. Nakanishi, T. Yoshinaga and Y. Kusuki, Gas Permeation Properties of Asymmetric Carbon Hollow Fiber Membranes Prepared from Asymmetric Polymer Hollow Fibers, 7. Membr. Sci. 160, 179 (1999). 

In addition to the polymer and facilitated transport membranes, novel materials are being proposed and investigated to achieve membranes with economically attractive properties. Carbon molecular sieve (CMS) membranes prepared by pyrolysis of polyimides displayed much better performance for olefin/paraffin separation than the precursor membranes [39, 46, 47]. Results obtained with CMS membranes indicated properties well beyond the upper-bond trade-off curve, as shown in Figure 7.8. Nonetheless, this class of materials is very expensive to fabricate at the present time. An easy, reliable, and more economical way to form asymmetric CMS hollow fibers needs to be addressed from a practical viewpoint. 

Figure 17.3, the reactant was fed into the solvent, while the product was extracted in water. The lipase was immobilized by entrapment method on asymmetric PAN hollow-fiber membranes. The process was run for several years with modules for the production plant of 60 m2 of active membrane area. 

Tanihara, N.H., Shimazaki, Y., Hirayama, S., et al. (1999). Gas permeation properties of asymmetric carbon hollow fiber membranes prepared from asymmetric polyamide hollow fiber. J. Membrane Sci., 160(2), 179—86. 

Asymmetric synthetic hollow fiber membranes designed for use in ultra-filtration/dialysis processes can provide an interesting support for immobilizing enzymes. 

Mansourizadeh, A., Ismail, A.F. 2011. A developed asymmetric RVDF hollow fiber membrane structure for COj absorption. Int. J. Greenh. Gas Control 5 374—380. 

Hollow fiber membranes with a positively charged nanofiltration selective layer have been fabricated by using asymmetric microporous hollow fibers made from a Torlon PAI type as the porous substrate followed by a post-treatment with poly(ethyleneimine) [79]. The membrane structure and the surface properties can be tailored by adjusting the polymer dope composition, spinning conditions, and the posttreatment parameters. 

Asymmetric Polyaniline Hollow Fibers for Membrane Applications Acid-Processing Route for tbe Fabrication of... 

Asymmetric Polyaniline Hollow Fibers for Membrane Applications... 

In our laboratory, asymmetric polyaniline hollow fiber membranes of varying morphologies for gas separations have been fabricated. The outer diameter of these hollow fibers was chosen to be less than 500 p.m since hollow fibers with these dimensions are typically used for low and medium pressure applications (feed pressure 50-100 psi). Norris et al. [53] showed that by adjusting the processing parameters it is possible to control the thickness, porosity, and location of the skin layer to provide a... 

The formation of macrovoids in these asymmetric polyaniline hollow fibers is undesirable as they weaken the mechanical strength and may lead to defects in the selective layer, which make them nonviable for many separations applications. The formation of macrovoids in hollow fiber membranes is generally caused by fast precipitation kinetics of the polymer solution in the coagulation bath. The formation of macrovoids when spinning polyaniline hollow fibers was foimd to be highly dependent on... 

Norris, I.D., A.G. Fadeev, J. Pellegrino, and B.R. Mattes. 2005. Development of integrally skinned asymmetric polyanUine hollow fibers for membrane applications. Synth Met 153 57. 

Jian, K. and Pintauro, P.N. 1997. Asymmetric PVDF hollow-fiber membranes for organic/ water pervaporation separations, 135 41-53. 

Ismail, A.F. and Yaacob, N. 2006. Performance of treated and untreated asymmetric polysulfone hollow fiber membrane in series and cascade module configurations for CO2/CH4 gas separation system. T Memh Sn. 275 151-165. 

Fig.l SEM Photomicrograph of a Cross-section of an Asymmetric Polysulfone Hollow Fiber Membrane Spun from N-methylpyrroildone/Formamide at 150 Magnification... 

Fig 5 The Performance of Asymmetric Polysulfone Hollow Fiber Membranes spun from N-methylpyrrolidone/Formamide as Function of Oxygen Plasma Ablation Time... 

Fig. 7 SEM Photomicrograph of the Outer Edge of an Asymmetric Polyethersulfone Hollow Fiber Membrane spun from N-methylpyrrolidone/Formamide at 20K Magnification... 

Fig.12 SEM Photomicrograph of the outer edge of an Asymmetric Polyphenylsulfone Hollow Fiber Membrane Spun from N-methylpyrrolidone/Forma-mide at 2OK Magnification...

Kusuki et al. [42] made the asymmetric carbon membranes by carbonization of asymmetric PI hollow fiber membranes. The effects of different experimental conditions on the membrane performance were investigated. They reported that those carbon membranes showed high permselectivities. 

Asymmetric carbon membranes were made by carbonization of asymmetric PI hollow fiber membranes by Tanihara et al. [43], In their study, it was found that the permeation properties of caibon membranes were hardly affected by feed pressure and exposure to toluene vapor. Furthermore, there was only little change in the permeation properties of the caibon membrane with the passage of time. 

---