Liquid purification or separation – Filter – Material
Patent
1983-12-22
1985-07-30
Welsh, Maurice J.
Liquid purification or separation
Filter
Material
585818, 585819, C08G 2032
Patent
active
045320411
ABSTRACT:
Asymmetric polyimide reverse osmosis membranes of high flux and selectivity for organic liquid separations are described. These membranes are prepared from undegraded polyimide by dissolving from 14-30 wt. % of the undegraded polymer in a dual solvent system comprising a polymer pro-solvent/anti-solvent wherein the pro-solvent is DMF and the anti-solvent is dioxane, wherein the ratio of anti-solvent/pro-solvent ranges from about 10:1 or more-1:1, preferably about 8:1-1.5:1, most preferably about 7:1-3:1; the polymer-solvent mixture is spread into a thin film of the desired thickness and permitted to evaporate for a time just sufficient to permit formation of an asymmetric dense active layer, i.e., within the range 2-120 seconds, preferably 2-60 seconds, most preferably 2-20 seconds before being immersed in a gelation bath.
The membranes may be fabricated in the form of sheets, tubes, hollow fibers, etc.
Mixtures of organic liquids, and especially mixtures of dewaxing solvents such as ketones, aromatic hydrocarbons and mixtures thereof, halogenated hydrocarbons such as dichloromethane, dichloroethane and mixtures of such halogenated hydrocarbons with ketones or aromatic hydrocarbons or other polar dewaxing solvents and dewaxed oils, are separated after completion of dewaxing operations, using the asymmetric polyimide reverse osmosis membrane described above.
REFERENCES:
patent: Re30351 (1980-07-01), Hoehn et al.
patent: 2947687 (1960-08-01), Lee
patent: 3179632 (1965-04-01), Hendrix
patent: 3179633 (1965-04-01), Endrey et al.
patent: 3546175 (1970-12-01), Angelo
patent: 3708458 (1973-01-01), Alberine
patent: 3816303 (1974-06-01), Wrasidlo
patent: 3822202 (1974-07-01), Hoehn
patent: 3853754 (1974-12-01), Gosser
patent: 3925211 (1975-12-01), Schumann et al.
patent: 4071590 (1978-01-01), Strathmann
patent: 4113628 (1978-09-01), Alegranti
patent: 4240914 (1980-12-01), Iwama et al.
patent: 4307135 (1981-12-01), Fox
patent: 4378324 (1983-03-01), Makino et al.
"New Polyimide Ultrafiltration Membranes for Organic Use", Iwama et al., Journal of Membrane Science, 11 (1982), 297-309.
"High Temperature Ultrafiltration Membrane", NASA Contract No. NAS7-100, Sarbalouki, JPL Invention Report 30-4918/NPO 15431.
"The Use of Solubility Parameters for Solvent Selection in Asymmetric Membrane Formation", Klein & Smith, Lowdale & Podall Editors, Reverse Osmosis Membrane Research, Plenum, NY, pp. 61-64.
"Asymmetric Polyimide Membranes for Filtration of Nonaqueous Solutions", Strathmann, Desalination 26 (1978), pp. 85-91.
"Development of Chlorine Resistant Membrane Asymmetric Polyimide Membrane and Porous Substrates", Final Report by Membrane Systems, Inc. to Office of Water Research & Technology, Sudak et al., Contract No. 14-34-0001-9515.
"Development of Chlorine Resistant Reverse Osmosis Membrane and Porous Membrane Support", Office of Water Research & Technology, May 1979, PB80-102973.
"Soluble Polyimides Derived from Phenylindane Diamine: A New Approach to Heat Resistant Protective Coatings", Bateman et al.
Shuey Harry F.
Wan Wankei
Allocca Joseph J.
Exxon Research and Engineering Co.
Welsh Maurice J.
LandOfFree
Asymmetric polyimide reverse osmosis membrane, method for prepar does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Asymmetric polyimide reverse osmosis membrane, method for prepar, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Asymmetric polyimide reverse osmosis membrane, method for prepar will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2371558