Abstract: A process for treating gas streams containing a sterilant gas and a diluent gas, such as sterilizer exhaust streams. The process involves a sterilant removal step and a diluent removal step. The sterilant removal step can be absorption, catalytic oxidation or some other chemical reaction. The diluent removal step includes a membrane separation step, and may include a condensation step. The permselective membranes used for the membrane separation step are typically selective for the diluent gas over other gases in the stream. The process removes essentially all the sterilant present in the feed stream, and typically removes 90% or more of the diluent. The process is particularly useful for treating ethylene oxide/CFC-12 mixtures.

Abstract: A spiral-wound pervaporation module, designed to achieve optimum permeate flow throughput. The module is of conventional design and construction, in that it incorporates membrane envelopes, within and between which are channels through which the feed and permeate streams flow. The feed and permeate channels are created by spacers on the feed and permeate sides of the membrane layers. The module is unconventional in that the permeate spacer is tailored for optimum permeate flow throughput. The tailoring is based on the discovery that the total permeate flow throughput from a module passes through a maximum as the resistance to vapor transport of the permeate spacer material is progressively decreased. The resistance to vapor transport along the permeate channel is kept below a value at which it has a significant adverse effect on the membrane flux and the membrane separation properties, yet at the same time the total module throughput is within an optimum range.

Abstract: A composite membrane particularly useful for gas separation or pervaporation. The membrane has three layers: a microporous substrate, an intermediate sealing layer, and a top permselective layer. The permselective layer is made by interfacial polymerization directly on the sealing layer. The sealing layer prevents penetration of the interfacial polymerization reagents into the substrate pores during membrane preparation and provides a gutter layer in the finished membrane.

Abstract: A refrigeration process including a refrigeration cycle, and refrigerant purge and recovery operations is disclosed. The refrigeration cycle may be a vapor compression cycle or an absorption cycle, for example. A purge stream is withdrawn from the refrigeration cycle and subjected to treatment by means of a membrane separation unit. The purge-stream treatment operation produces an essentially pure refrigerant stream, suitable for return to the refrigeration cycle, and an air stream, clean enough for direct discharge to the atmosphere. The process is applicable to most refrigerants, but is particularly useful in minimizing atmospheric emissions of chlorofluorocarbons, such as CFC-11 and CFC-12.

Abstract: A fractionation process for treating a gas stream containing organic vapor in a concentration technically or economically difficult to treat by standard waste control methods. Typically this concentration will be about 0.1-10% organic vapor. The process involves running the stream through a membrane system containing one or more membranes selectively permeable to the organic vapor component of the gas stream. The fractionation produces two streams: a product residue stream containing the organic vapor in a concentration less than about 0.5% and a product permeate stream highly enriched in organic vapor content. Both residue and permeate streams are then suitable for treatment by conventional separations or waste control technologies. The low concentration residue stream might be passed to carbon adsorption beds, for example, and the high concentration permeate stream might be subjected to condensation or incineration.

Abstract: A separation process for recovering organic components from liquid streams. The process is a combination of pervaporation and decantation. In cases where the liquid stream contains the organic to be separated in dissolved form, the pervaporation step is used to concentrate the organic to a point above the solubility limit, so that a two-phase permeate is formed and then decanted. In cases where the liquid stream is a two-phase mixture, the decantation step is performed first, to remove the organic product phase, and the residue from the decanter is then treated by pervaporation. The condensed permeate from the pervaporation unit is sufficiently concentrated in the organic component to be fed back to the decanter. The process can be tailored to produce only two streams: an essentially pure organic product stream suitable for reuse, and a residue stream for discharge or reuse.

Abstract: A protective material having a membrane layer and a sorbent layer. The membrane is a thin-film composite membrane permeable to water vapor but relatively impermeable to organic vapors. The sorbent layer includes activated carbon or other sorbent or reactive material, and captures traces of organic vapor that permeate the membrane layer. The material is particularly useful in intermediate-level protective clothing.

Abstract: A pervaporation process for separating organic contaminants from evaporator condensate streams is disclosed. The process employs a permselective membrane that is selectively permeable to an organic component of the condensate. The process involves contacting the feed side of the membrane with a liquid condensate stream, and withdrawing from the permeate side a vapor enriched in the organic component. The driving force for the process is the in vapor pressure across the membrane. This difference may be provided for instance by maintaining a vacuum on the permeate side, or by condensing the permeate. The process offers a simple, economic alternative to other separation techniques.

Abstract: A multilayer composite fabric material consisting of a woven or non-woven fabric support, a microporous membrane layer, and an ultrathin permselective surface coating, and optionally an intermediate sealing layer and a protective top layer; the material being freely permeable to water vapor but impermeable to toxic organic vapors.The material is suitable for fabricating protective clothing for use in industrial and military hazardous chemical enviornments.

Abstract: A transdermal patch for delivering nicotine for prolonged periods of 12-24 hours. The patch includes a rate-controlling membrane or monolith to keep the nicotine flux within useful and safe limits. The patch is typically replaced once a day, and can be used for smoking cessation therapy or in other situations where systemic nicotine delivery is indicated.

Abstract: A controlled release drug delivery system for placement in the periodontal pocket, gingival sulcus, tooth socket, wound or other cavity within the mouth. The system incorporates drug-containing microparticles in a fluid carrier medium, and is effective in the environment of use for up to 30 days.

Abstract: A membrane process for separating fluorinated hydrocarbon vapors is disclosed. The process employs a permselective membrane that is selectively permeable to fluorinated hydrocarbons over oxygen or nitrogen. The process involves contacting the feed side of the membrane with a gas mixture containing the fluorinated hydrocarbon vapor, and withdrawing from the permeate side a vapor enriched in the fluorinated hydrocarbon component. The driving force for membrane permeation is preferably provided by maintaining a partial vacuum on the permeate of the membrane. Eighty to 99% of the fluorinated hydrocarbon contained in the feedstream can be removed by the process. The permeate may be sufficiently enriched in fluorinated hydrocarbon to permit recovery and reuse. Very high membrane selectivities are not required.

Abstract: An ultrathin, high-flux composite membrane for use in gas separation. The membrane comprises a metal layer, typically 500.ANG. or less thick on a microporous support. The support may be as asymmetric Loeb-Sourirajan type membrane or a two-layer composite of a microporous substrate with a very thin sealing layer. The support gives mechanical strength to the membrane but does not contribute significantly to the selectivity. Optionally the metal layer may be overcoated with a second polymeric sealing layer to plug any defects and to protect the fragile surface from mechanical damage. The membrane is particularly useful in the purfication of hydrogen.

Abstract: A controlled release transdermal delivery system for nicotine administration. The system comprises an impermeable backing layer, a polyurethane matrix layer containing between about 5 wt % and 50 wt % nicotine, and an adhesive skin-contacting layer. The system is designed to administer nicotine for smoking cessation therapy or other uses over a period of 24 hours or more.

Abstract: There is disclosed an improved complex coacervation process for microencapsulation of core ingredients that are partially soluble in the microcapsule walls wherein the core ingredient is first mixed with a coacervation adjacent prior to forming a first colloidal emulsion of core ingredient, and, after combining the first emulsion with a second colloidal solution and cooling to cause gelation, a water-soluble wax derivative is added. No pH adjustment or dilution is necessary, and very high yields of non-agglomerated microcapsules are obtained, both in terms of quantity of microcapsules and content of core ingredient. When deet is the core ingredient there is obtained a long-lasting mosquito repellent.

Abstract: A controlled release drug delivery system for placement in the periodontal pocket. The system comprises a plurality of drug-containing microparticles or microcapsules, between 10 and 500 microns in size, suspended in a pharmaceutically acceptable carrier medium, and is capable of maintaining an effective level of drug in the periodontal pocket for a period of 1 to 30 days.

Abstract: A composite lumen-side feed reverse osmosis membrane and its preparation are disclosed, the membrane comprising a polymeric microporous-walled hollow fiber support with an interfacially-polymerized ultrathin semipermeable salt-rejecting layer engrafted on the lumen or bore of the hollow fiber support, the support having walls that are substantially completely free of finger-like voids in excess of about 5 microns in the area of the wall adjacent the lumen. The preparation of the support comprises coaxially spin-casting (1) a fiber-forming solution containing a pore-forming material with (2) a lumen-forming fluid comprising from about 50 to about 70 vol % organic solvent in water.

Abstract: Prills of pharmaceutically acceptable material are coated first with a water-permeable polymeric matrix containing a water-soluble pharmaceutically beneficial agent and then overcoated with a water-permeable film containing dispersed therein a water-soluble, particulate pore-forming material.

Abstract: Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption.