Showing papers on "Reverse osmosis published in 1981"

Review of reverse osmosis membranes and transport models

Abstract: After a brief introduction to membrane processes in general, and the reverse osmosis process in particular, the structure and properties of membranes and membrane transport theory are described. The mechanism of salt rejection and transport properties of membranes are discussed in detail. Solubility, diffusivity, and permeability of membranes to solutes and solvents are reviewed critically and compared with each other. Special attention is given to two particular types of membranes, cellulose acetate (CA) and aromatic polyamide (AP) membranes, which are often used for water desalination. The major portion of this article is devoted to the review and discussion of membrane transport theory with application to the reverse osmosis and ultrafiltralion processes. It is shown that the solvent flux can be represented reasonably well by linear models such as the solution-diffusion model (Lonsdale, et al., 1965). The contribution of pore flow to the solvent flux is small. The solute flux, however, is not ...

Interfacial Synthesis in the Preparation of Reverse Osmosis Membranes

Abstract: Reverse osmosis membranes are currently finding increasing use in the production of potable water from salt-laden water sources, and in the purification and recycle of industrial process waters. Most reverse osmosis membranes are comprised either of polyamide hollow fibers or cellulose acetate sheet films. A new type of reverse osmosis membrane, made by the interfacial synthesis of ultrathin membranes directly on microporous support media, is being explored. Two types of interfacially formed membranes are specifically described. One is based on an ultrathin polyamide barrier layer made by interfacial reaction of polyethylenimine with isophthaloyl chloride. The barrier material is supported by a heat-polymerized intermediate zone of polyethylenimine, supported in turn by a microporous polysulfone substrate. The second membrane consists of a polyamide formed from piperazine and a mixed acyl halide reagent. This nonpolymeric amine leads to a different surface texture and the absence of an intermedia...

Ultrafiltration membranes and applications

Abstract: I. Fundamentals.- Fifteen Years of Ultrafiltration: Problems and Future Promises of an Adolescent Technology.- Production, Specification, and Some Transport Characteristics of Cellulose Acetate Ultrafiltration Membranes for Aqueous Feed Solutions.- Chemical and Morphological Effects of Solute Diffusion Through Block Copolymer Membranes.- Practical Aspects in the Development of a Polymer Matrix for Ultrafiltration.- Permeability Parameters of a Novel Polyamide Membrane.- Formation of Poly(methyl methacrylate) Membranes Utilizing Stereocomplex Phenomenon.- Advances in Hollow Fiber Ultrafiltration Technology.- Transport Behavior of Asymmetric Polyamide Flat Sheet Membranes and Hollow-Fine Fibers in Dialysis-Osmosis and Hyperfiltration Experiments.- Separation of Macromolecules by Ultrafiltration: Influence of Protein Adsorption, Protein-Protein Interactions, and Concentration Polarization.- Ultrafiltration in an Unstirred Batch Cell.- II. Ultrafiltration Membrane Formation, Characterization and Concentration Polarization.- Morphology of Skinned Membranes: A Rationale from Phase Separation Phenomena.- Characterization Technique of Straight-Through Porous Membrane.- Flow Rates of Solutions Through Ultrafiltration Membranes Monitored by the Structure of Adsorbed Flexible Polymers.- Protein Ultrafiltration: Theory of Membrane Fouling and Its Treatment with Immobilized Proteases.- Boundary Layer Removal in Ultrafiltration.- Initial Time Stirred Protein Ultrafiltration Studies with Partially Permeable Membranes.- Electrophoretic Techniques for Controlling Concentration Polarization in Ultrafiltration.- Prediction of Permeate Fluxes in UF/RO Systems.- Demetallation of Chelating Polymers by Diafiltration in the Presence of a Permeable Complexing Agent.- III. Industrial Applications of Ultrafiltration.- Progress in the Industrial Realizations of Ultrafiltration Processes.- Recent Developments of Membrane Ultrafiltration in the Dairy Industry.- Ultrafiltration of Whole and Skim Milk.- Factors Affecting the Application of Ultrafiltration Membranes in the Dairy Food Industry.- Vegetable Protein Isolates and Concentrates by Ultrafiltration.- Negative Rejections of Cations in the Ultrafiltration of Gelatin and Salt Solutions.- The Application of Ultrafiltration to Fermentation Products.- Concentrating Fruit Juices by Reverse Osmosis.- Surfactant Micelle Enhanced Ultrafiltration.- IV. Industrial Applications of Ultrafiltration.- Thin-Channel Ultrafiltration, Theoretical and Experimental Approaches.- Automated Hollow Fiber Ultrafiltration: Pyrogen Removal and Phage Recovery from Water.- Depyrogenation of Human Chorionic Gonadotropin.- Ultrafiltration of Prothrombin Complex.- Pyrogen Removal by Ultrafiltration - Applications in the Manufacture of Drugs and U.S.P. Purified Water.- High Flux Cellulosic Membranes and Fibers for Hemofiltration.- V. Biomedical Applications of Ultrafiltration.- Microporous Membrane Filtration for Continuous-Flow Plasmapheresis.- Determination of Graetz Solution Constants in the In-Vitro Hemofiltration of Albumin, Plasma, and Blood.- Ultrafiltration in Patients with Endstage Renal Disease.- Development of Novel Semipermeable Tubular Membranes for a Hybrid Artificial Pancreas.- Liver Tumor Cells Grown on Hollow Fiber Capillaries: A Prototype Liver Assist Device.- Application of Ultrafiltration Techniques to the Production of Human Plasma Protein Solutions for Clinical Use.- Ultrafiltration as an Alternative to Reprecipitation and Lyophilization in Cohn Fractionation.- Production of Protein Hydrolyzates in Ultrafiltration-Enzyme Reactors.- VI. Ultrafiltration Applications in Environmental Problems.- Ultrafiltration - The Membranes, the Process and Its Application to Organic Molecule Fractionation.- Use of Negatively-Charged Ultrafiltration Membranes.- Electrodialysis and Ultrafiltration as a Combined Process.- A Study of the Fouling Phenomenon During Ultrafiltration of Cottage Cheese Whey.- Ultrafiltration/Activated Sludge System - Development of a Predictive Model.- Hyperfiltration for Recycle of 82 C Textile Water Wash.- Application of Acrylonitrile-Copolymer Membrane to Cationic Electro-Deposit Coating.- The Application of Novel Ultrafiltration Membranes to the Concentration of Proteins and Oil Emulsions.- Using Industrial Membrane Systems to Isolate Oilseed Protein Without an Effluent Waste Stream.- Concluding Remarks.- Contributors.

Reverse-osmosis water purifier apparatus and method

Abstract: An apparatus and method whereby after a reverse-osmosis water purifier system has been shut down, the first quantity of water, which emanates from the reverse-osmosis filter, does not flow through the pure water storage tank but instead to the drain. Therefore, the water in the reverse-osmosis filter, and which has become contaminated as the result of standing in the filter so that a substantial amount of osmosis can occur, does not contaminate the pure water in the storage tank or system but instead is discarded.

Ultrafiltration and reverse osmosis tubular membrane module

Abstract: An ultrafiltration and reverse osmosis module comprising a tubular casing having a plurality of tubular membrane assemblies spaced therein by spacing plates, in stepped end portions of the casing bore, and held therein by sealing plates clamped to flanges on the ends of the casing. The tubular membrane assemblies are sealed around bores in the spacing plates and boxes in the sealing plates by "O"-rings and are held against collapse by sleeves in the ends of the tubular membrane assemblies.

Scale inhibitor for reverse osmosis water purification system

Abstract: A method for inhibiting scale build up in reverse osmosis water purification system is disclosed. The method uses a composition composed of low molecular weight polyacrylic and phytic acid in a synergistic combination and significantly reduces build up of calcium, magnesium, and/or iron scale.

Process for the treatment of water containing nitrate

Abstract: In a process for the treatment of in particular water-containing nitrate, such as, for example, ground water, brackish water or the like, the water is separated into a low-nitrate permeate and a high-nitrate concentrate by means of reverse osmosis and the latter is evaporated until precipitation of the solid. In order to be able to operate such a process more cost-efficiently, the concentrate is freed from hardness formers, concentrated by means of a membrane separation process to give a salt solution, which is then evaporated.

Novel ion‐containing reverse osmosis membranes. II. Reverse osmosis properties

Abstract: The reverse osmosis properties of ion-containing membranes prepared by 60Co mutual irradiation grafting of 2-vinylpyridine to poly(3,3-bis(chloromethyl)oxetane) (polyoxetane, Penton) followed by quaternization with methyl bromide are presented. In general, the volumetric fluxes varied linearly with pressures up to 55 atm. Katchalsky's treatment of membrane permeability was used to analyze the data. Membrane constants and diffusion coefficients of water and sodium chloride were determined with membranes containing different volume fractions of water. The diffusion coefficients of water in the membranes were of the same order of magnitude as the self-diffusion coefficient of water (∼3 × 10−5 cm2/s). The diffusion coefficients of sodium chloride in the membrane were of the order of 10−7 cm2/s. The diffusion coefficients increased with hydration, and the salt rejections were markedly affected by the external salt concentrations. The apparent energies of activation for the volumetric flux were calculated in distilled water and in 0.5% sodium chloride solution.

Recovery of organic acid

Abstract: PURPOSE: To recover an organic acid from a waste liquid containing the organic acid, by treating the liquid with a reverse osmosis membrane to concentrated and recover the major portion of the acid, adding an alkaline agent to the permeated liquid to form an organic acid salt, concentrating the liquid by the above described treatment, and evaporating the concentrated liquid in the presence of an acid to recover the residual portion of the acid. CONSTITUTION: A waste liquid 1 containing organic acid is pressurized with a high- pressure pump and fed to the first stage reverse osmosis membrane apparatus 1. The produced concentrated liquid 3 containing the major portion of the organic acid is recovered, and the separated permeated liquid 4 containing organic acid is added with an alkaline agent 5 to form an organic acid salt. The liquid is pumped with a high- pressure pump to the second-stage reverse osmosis apparatus 6. The concentrated liquid 7 containing the organic acid salt and obtained from the apparatus 6 is evaporated (9) in the presence of an acid to recover the remaining portion of the organic acid. The quality of the permeated liquid 8 is almost equal to the quality of pure water. EFFECT: A most 100% of the organic acid can be recovered. The amounts of the alkaline agent and the acid can be saved, the load of evaporation and concentration can be lowered, and the energy-saving, the reutilization of the permeated liquid, and the prevention of environmental pollution are made possible. COPYRIGHT: (C)1983,JPO&Japio

Reverse osmosis expansible pressurized permeate storage having permeate and concentrate controls

Abstract: A water treatment and storage system includes a reverse osmosis treatment unit having an untreated water input line, a treated water output line and a bleed water output line. An expandable container, compressed by a spring arrangement, is provided for storing treated water. A container valve, connecting the reverse osmosis treatment unit and the expandable container, terminates the flow of treated water to the container when a predetermined quantity of water has been accumulated therein. The container valve further includes a bleed valve arrangement connecting the bleed water output line and a drain line. The bleed valve arrangement terminates the flow of bleed water to the drain line after the container has accumulated the predetermined quantity of treated water.