Showing papers on "Reverse osmosis published in 1970"
Patent•
24 Sep 1970
TL;DR: In this article, a method for cleaning and rejuvenating a USED REVERSE OSMOSMOSIS MEMBRANCE by TREATING the MEMBRANE in SITU with a solution of OXALIC ACID is presented.
Abstract: A METHOD FOR CLEANING AND REJUVENATING A USED REVERSE OSMOSIS MEMBRANCE BY TREATING THE MEMBRANE IN SITU WITH A SOLUTION OF OXALIC ACID. NOT ONLY ARE DELETERIOUS DEPOSITS REMOVED FROM THE MEMBRANE, BUT THE ORGINAL OSMOTIC PROOPERTIES OF THE MEMBRANE MAY BE PARTIALLY RESTORED. THE MEMBRANE PROPERTIES MAY BE FURTHER IMPROVED BY A SUBSEQUENT TREATMENT WITH A SWELLING AGENT OR A HOT WATER SOLUTION.
51 citations
TL;DR: In this paper, a typical evaporation rate curve plotted on a semilog scale consists of an initial linear part from whose slope evapore rate constants b have been determined, and an optimum value of b exists for best membrane performance.
Abstract: Quantitative data on solvent evaporation rates and equilibrium phase separation compositions corresponding to different film casting conditions are given, and the results are discussed with reference to reverse osmosis data on membrane performance. A typical evaporation rate curve plotted on a semilog scale consists of an initial linear part from whose slope evaporation rate constants b have been determined. For a given casting solution composition and temperature, an optimum value of b exists for best membrane performance, and identical values of b result in same membrane performance. Treating the casting solution as a polymer–solvent–nonsolvent ternary system, the data on equilibrium phase separation compositions have been plotted in a triangular diagram for solution temperatures of −10°, 0°, and 24°C. The data indicate that even small changes in solution temperature can bring about significant changes in solution structure and hence membrane performance, and useful conclusions on solution structure can be drawn from such phase equilibrium diagrams. The data and correlations presented here offer a quantitative confirmation of the governing significance of the solution structure-evaporation rate concept relating to the mechanism of phase separation and pore formation in the surface region during the process of making reverse osmosis membranes.
50 citations
Patent•
15 Oct 1970
TL;DR: A high quality water purification system for providing water for use under near aseptic conditions such as in hemodialysis is described in this paper, where water is purified by passing it respectively through a reverse osmosis bank, a deionizer, and at least one submicron filter in series.
Abstract: A high quality water purification system for providing water for use under near aseptic conditions such as in hemodialysis including an arrangement whereby water is purified by passing it respectively through a reverse osmosis bank, a deionizer, and at least one submicron filter in series, with means for insuring a constant flow of waste water to a drain from the outlet side of the reverse osmosis bank and means for by-passing water around the deionizer unit
44 citations
TL;DR: The reverse osmosis technique is applicable for the separation of binary mixtures of alcohols and/or hydrocarbons, including azeotropic and isomeric mixtures as discussed by the authors.
Abstract: : The reverse osmosis technique is applicable for the separation of binary mixtures of alcohols and/or hydrocarbons, including azeotropic and isomeric mixtures. The porous structures of the cellulose acetate membranes used were affected by the composition of the feed solution in contact with them; hydrocarbon liquids tended to collapse their porous structures on continued contact. Hydrogen bonding and solubility parameter may offer valid criteria of preferential sorption for nonelectrolyte binary feed mixtures containing components whose solubilities are governed primarily by either polar or dispersion forces. (Author)
43 citations
Patent•
28 Sep 1970
TL;DR: In this paper, the OSMOIS MEMBRANE is used for liquid and liquid purification, by operation the APPARATUS USING a particULAR time series of pressure and/or solvability.
Abstract: OSMOIS MEMBRANE ARE EFFECTIVELY REJUVENATED FOR SUBSTANTIALLY CONTINUOUS UTILIZATION. LIQUID PURIFICATION IS ACCOMPLISHED USING THE SAME PRESSURE DIALYSIS OR REVERSE OSMOSIS MEMBRANE IN DESALINATION OR FLUID PROCESSING APPARATUS TO ACHIEBVE TWO OR MORE SUCCESSIVE STAGES OF PURIFICATION, BY OPERATION THE APPARATUS USING A PARTICULAR TIME SEQUENCE PRESSURES AND/OR SOLUTION HAVING DIFFERENT CONCENTRATION AND CHEMICAL COMPOSITIONS, THE APPARATUS AND PARTICULARLY THE REVERSE
39 citations
Patent•
15 Jul 1970
TL;DR: A water purifier for removing dissolved substances and solid impurities from water supplied at an elevated pressure to a reverse osmosis element located inside a pressurized storage tank is described in this article.
Abstract: A water purifier for removing dissolved substances and solid impurities from water supplied at an elevated pressure to a reverse osmosis element located inside a pressurized storage tank. As purified water from the element is collected within the tank it further compresses air in the tank, which air is used to force the purified water from the tank when used. A valve connected in the conduit supplying water to the element is responsive to air pressure within the storage tank to cut off the water flow when the supply of purified water in the tank reaches a predetermined level.
37 citations
TL;DR: In this paper, a set of porous cellulose acetate membranes were made using the same casting solution composition and gelation conditions but varying the casting solution temperature and solvent evaporation conditions, and they were tested in reverse osmosis experiments at 250 psig using aqueous feed solutions containing 3500 ppm NaCl.
Abstract: Several sets of porous cellulose acetate membranes were made using the same casting solution composition and gelation conditions but varying the casting solution temperature and solvent evaporation conditions. The films were tested in reverse osmosis experiments at 250 psig using aqueous feed solutions containing 3500 ppm NaCl. The results show that the product rate obtained at a given level of solute separation is independent of evaporation time in the range tested and, for a given casting solution composition, the temperature of the casting solution and conditions of solvent evaporation during film formation together constitute an important interconnected variable governing the porous structure of the resulting membranes. These results offer a new approach to the problem of developing more productive reverse osmosis membranes and have led to a new class of porous cellulose acetate membranes capable of giving product rates 100% to 150% higher than those of the best membranes reported, at any given level of solute separation under the experimental conditions used. These results are of practical importance in low-pressure reverse osmosis applications.
32 citations
01 Jan 1970
TL;DR: In this article, a model of water flow, which includes coupling to chemical reactions, is discussed, based on the radial movement of matter from the outside solution into the xylem tubes in the centre of the root.
Abstract: Water flows are described in root segments from which the central stele had been removed ('sleeves'). The water flow was measured either as an exchange flow, using tracers, or as net osmotic flow. Metabolic inhibitors inhibited both types of flow. From the above measurements, the over-all hydraulic conductivity (Lp) and permeability coefficient (w) for water were calculated. By measuring the effect of water drag on the flow of sucrose and urea, reflection coefficients (a) were calculated for sucrose and urea. A model of water flow, which includes coupling to chemical reactions, is discussed. We wish to restrict ourselves to the radial movement of matter from the outside solution into the xylem tubes in the centre of the root. If relatively short segments are used, it can be assumed that movement of matter is restricted to one dimension, changes occurring in the system along the radial coordinate only. Transport phenomena occurring in roots can be approached by considering two extreme cases of steady flow: (a) If the ratio of water flow to solute flow exceeds the ratio of water to solute in the bathing medium, then the concentration of salts in the xylem vessels will be lower than that in the outer solution. In other words, partial separation of solute and solvent occurs. This could be brought about by some purely physical process of separation, such as reverse osmosis. This case is found in mangroves (Scholander, Hammel, Hemmingsen, and Garey, 1962). (b) If the ratio of solute flow to water flow exceeds the ratio of solute to water in the medium, the salt concentration will be higher in the vessels than in the outer solution. Here again partial separation between solute and water occurs, but in the opposite direction. Thus osmotic work is again performed by the root system. WITH ONE PLATE IN THE TEXT
31 citations
TL;DR: In this paper, the same authors used freeze-dried porous cellulose acetate reverse osmosis membranes to demonstrate the existence of mobile and immobile sorbed layers and the governing influence of surface flow in gas-phase reverse Osmosis separations.
Abstract: The permeations of helium, hydrogen, methane, ethylene, nitrogen, and argon, and helium–methane, nitrogen–ethylene, oxygen–nitrogen, and sulfur dioxide–nitrogen mixtures have been studied using freeze-dried porous cellulose acetate reverse osmosis membranes. The results illustrate the existence of mobile and immobile sorbed layers and the governing influence of surface flow in gas-phase reverse osmosis separations. Preshrunk freeze-dried porous cellulose acetate membranes seem to offer a practical means of utilizing the reverse osmosis process for recovering helium from natural gas and separating sulfur dioxide from flue gases.
28 citations
01 Jan 1970
TL;DR: The application of membrane processes to industrial separations is becoming a reality and many of these involve the process of membrane ultrafiltration, which process has demonstrated a capability for treating a variety of industrial solutions.
Abstract: The application of membrane processes to industrial separations is becoming a reality. For operations requiring concentration and purification of aqueous streams ranging from fermentation broths containing products such as enzymes and pharmaceuticals, to brackish and polluted waters, small scale commercial membrane units are presently in operation. Many of these involve the process of membrane ultrafiltration, which process has demonstrated a capability for treating a variety of industrial solutions.
23 citations
TL;DR: In this paper, a series of crosslinked hydroxyethyl methacrylate (HEMA) membranes for reverse osmosis desalination has been prepared, which are synthesized by polymerizing the monomers as a thin homogeneous film.
Abstract: A series of crosslinked hydroxyethyl methacrylate (HEMA) membranes for reverse osmosis desalination has been prepared. The crosslinkers used were trimethylol propane trimethacrylate (TPT) or ethylene glycol dimethacrylate (EGD). Membranes were synthesized by polymerizing the monomers as a thin homogeneous film. In addition to reverse osmosis tests, the membranes were also characterized by osmosis experiments and sorption measurements. The reverse osmosis water flux (1500 psi applied pressure, 4% NaCl brine, pH = 5) for these membranes decreases from 0.6 gallonmil/ft2-day (GMFD) to 0.055 GMFD and salt rejection increase from 78% to a maximum of 94% as the amount of TPT is increased from 0 to 11 mole-%. Water contents decrease from 42% to 15% over the same range of crosslinker, but the preferential sorption of water to salt does not vary. Thus, rises in reverse-osmosis semipermeability were found to result from changes in water–salt diffusivity ratios. The mechanism of permselectivity has been interpreted in terms of parallel diffusive fluxes across the membrane of primary H-bonded water and secondary water plus salt ions.
Patent•
09 Apr 1970
TL;DR: A liquid treatment system, involving pressure exchange pumps for positive control of reverse osmosis liquid purification, which overcomes corrosion and supersaturation problems is described in this article, where the authors present a liquid treatment scheme.
Abstract: A liquid treatment system, involving pressure exchange pumps for positive control of reverse osmosis liquid purification, which overcomes corrosion and supersaturation problems
Patent•
25 Sep 1970
TL;DR: A water purifying device employing a reverse osmosis water purification element that process feed water under line pressure producing purified product water that is accumulated in a compressible container is described in this paper.
Abstract: A water purifying device employing a reverse osmosis water purifying element that process feed water under line pressure producing purified product water that is accumulated in a compressible container. The container supplies the product water upon operation of a control valve to a product water supply outlet. The control valve directs feed water under line pressure to compress the compressible container and thus force the product water at line pressure to the water supply outlet. This use of the feed water causes an increased feed water flow through the reverse osmosis water purifying element flushing out the element. A
Patent•
15 Apr 1970TL;DR: In this article, a solution of a polybenzimidazole polymer is deposited upon a support to form a wet film, an amount of solvent is evaporated from the wet film sufficient to allow the formation of a thin layer of higher density at the exposed surface of the film, and the resulting film is washed to remove residual solvent and thereby form a semipermeable polybenzinimideazole membrane which membrane is then employed in the reverse osmosis process.
Abstract: A process for desalinization of water by reversed osmosis is disclosed particular utility in the separation of components of a solution. A solution of a polybenzimidazole polymer is deposited upon a support to form a wet film, an amount of solvent is evaporated from the wet film sufficient to allow the formation of a thin layer of higher density at the exposed surface of the film, and the resulting film is washed to remove residual solvent and thereby form a semipermeable polybenzimidazole membrane which membrane is then employed in the reverse osmosis process.
Patent•
15 Jun 1970
TL;DR: Hygroscopic liquid used to dehydrate wet gas streams is regenerated by causing the liquid to flow through a reverse osmosis system after which the liquid is stored and/or reused for dehydration.
Abstract: Hygroscopic liquid used to dehydrate wet gas streams is regenerated by causing the liquid to flow through a reverse osmosis system after which the liquid is stored and/or reused for dehydration.
Book•
01 Mar 1970
TL;DR: The Use of Membrane Diffusion as a Tool for Separating and Characterizing Naturally Occurring Polymers and anomalous Transport of Penetrants in Polymeric Membranes is examined.
Abstract: The Use of Membrane Diffusion as a Tool for Separating and Characterizing Naturally Occurring Polymers.- Anomalous Transport of Penetrants in Polymeric Membranes.- Application and Theory of Membrane Processes for Biological and Other Macromolecular Solutions.- Solute Polarization and Cake Formation in Membrane Ultrafiltration: Causes, Consequences, and Control Techniques.- Enzyme Processing Using Ultrafiltration Membranes.- A Consideration of the Parameters Governing Membrane Filtration - Particularly of Proteinaceous Solutions.- Separation of Blood Serum Proteins by Ultrafiltration.- Production of Acidic Salt With Substitution Reaction by Means of Ion-Exchange Membrane Electrodialysis.- Hydrometallurgical Separations by Solvent Membranes.- Low-Pressure Ultrafiltration Systems for Wastewater Contaminant Removal.- Industrial Waste Treatment Opportunities for Reverse Osmosis and Ultrafiltration.- Ultrafiltration Water Treatment.- Reverse Osmosis: Application to Potato-Starch Factory Waste Effluents.
Patent•
30 Mar 1970
TL;DR: A reverse osmosis liquid purification unit particularly adapted for home use in conjunction with low pressure water systems is described in this paper, which is adapted to receive water from a low pressure source to provide pure water that would otherwise be unobtainable for such purposes as drinking and direct all unpurified water to appliances within the home utilizing water without wastage.
Abstract: A reverse osmosis liquid purification unit particularly adapted for home use in conjunction with low pressure water systems. The unit is adapted to receive water from a low pressure source to provide pure water that would otherwise be unobtainable for such purposes as drinking and direct all unpurified water to appliances within the home utilizing water without wastage.
Journal Article•
Patent•
09 Dec 1970
TL;DR: A SEMI-PERMEABLE MEMBRANE CONTAINING A SUPPORTIVE LAYER and a LIPID CONTAINing OSMOTIC SKIN LAYer of a POLYMERIC FILM Forming CELLULOSIC MATERIAL is made by as discussed by the authors.
Abstract: A SEMI-PERMEABLE MEMBRANE CONTAINING A SUPPORTIVE LAYER AND A LIPID CONTAINING OSMOTIC SKIN LAYER OF POLYMERIC FILM FORMING CELLULOSIC MATERIAL IS MADE BY (1) ADMIXING FILM FORMING CELLULOSIC MATERIAL, SOLVENT, SWELLING ADDITIVE AND LIPID TO PROVIDE A CASTING SOLUTION (2) CASTING A FILM FROM THE SOLUTION (3) DRYING THE FILM (4) LEACHING THE FILM TO FORM A SEMI-PERMEABLE OSMOTIC SKIN MEMBRANE CONTAINING A RESIDUE OF LIPID, AND (5) OPTIONALLY CURING THE MEMBRANE.
TL;DR: In this article, the rejection of boric acid by different types of reverse osmosis membranes has been measured, and the results obtained with mannitol additions are consistent with the known complex-formation equilibria.
TL;DR: A reverse osmosis plant for preparation of dialysis water is described and a high flow rate of the water across the membrane a filtra is described.
Abstract: A reverse osmosis plant for preparation of dialysis water is described. With a total cellulose acetate membrane area of 1.8 m2 and a high flow rate of the water across the membrane a filtra
TL;DR: In this paper, a film prepared from vinylene carbonate with the addition of 8% acrylonitrile was found to give the best salt rejection; salt rejection increased with the number of polymer coats deposited.
Abstract: Reverse osmosis membranes have been prepared by the deposition of thin films on to the surface of a porous support membrane by glow discharge polymerisation. A film prepared from vinylene carbonate with the addition of 8% acrylonitrile was found to give the best salt rejection; salt rejection increased with the number of polymer coats deposited.
TL;DR: In this paper, a simple method for predicting the performance of Loeb-Sourirajan type porous cellulose acetate membranes for low concentrations of mixed solutes in aqueous feed solution systems involves two or more inorganic salts with a common ion.
Abstract: : A simple method for predicting the performance of Loeb-Sourirajan type porous cellulose acetate membranes for low concentrations of mixed solutes in aqueous feed solution systems involves two or more inorganic salts with a common ion. The method requires only data on membrane specifications and the applicable mass transfer coefficient correlation for the corresponding single solute systems. (Author)
TL;DR: In this paper, a nonlinear programming problem was formulated with the objectives of maximizing product flux and determining the optimal arrangement of assemblies with respect to fabrication temperature, and the solution of this problem pointed out a number of important things; most significant of which is that substantial gains can be made in reducing the size of reverse osmosis systems and thus reducing the cost of the water produced.
TL;DR: The polyvinylpyrrolidone (PVP)-polyisocyanate system forms a series of hydrophilic materials, the water permeability and selectivity of which can be varied over a wide range as mentioned in this paper.
Patent•
23 Apr 1970
TL;DR: A membrane module for use in solvent separation by reverse osmosis is described in this paper, where a conduit is provided for directing a liquid mixture under reverse Osmosis operating pressure to the interior of the tubular membranes together with a conduit for receiving the solvent from the interface of the membranes and the liquid impervious tubes.
Abstract: A membrane module for use in solvent separation by reverse osmosis. Tubular membranes are mounted in liquid impervious thinwalled tubes, all within a pressure vessel, with a conduit provided for directing a liquid mixture under reverse osmosis operating pressure to the interior of the tubular membranes together with a conduit for receiving the solvent from the interface of the membranes and the liquid impervious tubes. There is also provided a conduit communicating with the high pressure liquid mixture flow path to provide liquid under the high pressure to the exterior of the liquid impervious tubes to thereby provide a support for the tubes and thus, the membrane therewithin, during reverse osmosis operating conditions.
Patent•
27 Oct 1970
TL;DR: In this article, the production of a non-hazing starch conversion scheme with a D.E. of from about 5 to about 18 was discussed, and the number of converts was reduced from about 20 to 40.
Abstract: PROCESS FOR THE PRODUCTION OF A NON-HAZING STARCH CONVERSION SYRUP HAVING A D.E. OF FROM ABOUT 5 TO ABOUT 18 WHICH COMPRISES FIRST HYDROLYZING STARCH TO A D.E. OR FROM ABOUT 20 TO 40 AND THEREAFTER SUBJECTING THE RESULTING STARCH CONVERSION SYRUP TO REVERSE OSMOSIS UNTIL THE D.E. OF THE SYRUP HAS BEEN REDUCED TO FROM ABOUT 5 TO ABOUT 18.
Patent•
08 May 1970
TL;DR: In this article, the authors present an ACRYLIC (Adaptive Scale-Formation on the Surface of MEMBRANES in Reverse OSMOSIS APPARATUS) approach.
Abstract: THIS INVENTION RELATES TO A PROCESS FOR INHIBITING SCALE FORMATION ON THE SURFACE OF MEMBRANES IN REVERSE OSMOSIS APPARATUSES. THE PROCESS UTILIZES AS AN ADDITIVE TO THE WATER PRIOR TO ITS PASSAGE THROUGH THE APPARATUS AN ACRYLIC COMPOSITION FORMED FROM ABOUT 80 TO 90 PARTS BY WEIGHT ACRYLIC ACID, ABOUT 7 TO 15 PARTS BY WEIGHT THIOGLYCOLIC ACID AND ABOUT 1.5 TO 5 PARTS BY WEIGHT AMMONIUM PERSULFATE.