Yeda Research and Develpment & Co. Ltd

Ben-Gurion University of the Negev Research and Development Authority

Research Products Rehovot Ltd.

Other

B.g. Negev Technologies and Applications Ltd.

Sor-van Radiation Ltd.

Ora Kedem

Charles Linder

Mordechai Perry

Yoram Oren

Abraham Kedem

Rami Messalem

Abraham Warshawsky

Gerald B Tanny

Jack Gilron

Naphtali Daltrophe

Eliyahu Korin

Viatcheslav Freger

Tamar Robinson

Menashe Lev

Avraham Kedem

Yelena Mirsky

Galina Saveliev

Jonathan Ben-Dror

Ludmilla Schechtmann

The present invention provides anion exchange membranes, processes for producing same and uses thereof. The anion exchange membranes according to embodiments of the present invention achieve a desirable combination of low resistance, high permselectivity and low degree of dimensional swelling. Anion exchange membranes according to embodiments of the present invention are also cost effective.

Anion exchange membranes, methods of preparation and uses

There is provided herein a membrane or film comprising one or more aromatic ionomers covalently crosslinked through aryl-aryl (&#x2014;Ar&#x2014;Ar&#x2014;), aryl-ether-aryl (&#x2014;Ar&#x2014;O&#x2014;Ar&#x2014;), aryl-sulfide-aryl (&#x2014;Ar&#x2014;S&#x2014;Ar&#x2014;), aryl-sulfone-aryl bonds, or any combination thereof, wherein said one or more aromatic ionomers further comprises at least one electron withdrawing group adapted to improve oxidant resistance of said membrane or film.

Chemically resistant membranes, coatings and films and methods for their preparation

There are provided herein selective membranes, such as composite membranes, and/or films and processes for their preparation. The membranes and/or films have a given morphology which may be stabilized, for example against swelling and chemical degradation, by covalent crosslinking and optionally, in addition, by hydrophobization. There is provided a membrane and/or film and a process for the preparation thereof, the membrane and/or film include an ionomer and/or polyelectrolyte crosslinked through aryl-aryl (&#x2014;Ar&#x2014;Ar&#x2014;), aryl-ether-aryl (&#x2014;Ar&#x2014;O&#x2014;Ar&#x2014;) and/or aryl-sulfide-aryl (&#x2014;Ar&#x2014;S&#x2014;Ar&#x2014;) bonds.

Membranes, coatings and films and methods for their preparation

Process for producing ion exchange membranes. A matrix material that comprises a polymeric component chosen from the group consisting of monomeric and oligomeric polymer precursors and cross-linkable polymers is provided. Ion cation or anion exchange particles, or proton or hydroxyl or ion conducting particles, or cation or anion exchange polymers, or proton or hydroxyl or ion conducting polymers are introduced in the matrix. The particles are mixed or the polymer is dissolved with the matrix. The resulting mixture is formed into membrane configuration. The particles or the domains of the polymer formed by polymer-matrix phase separation upon solvent evaporation or cooling, are ordered by an electric field. If the matrix comprises or consists of a polymer precursor or a cross-linkable polymer, the precursor is cured concurrently with the ordering of the particles, or if the matrix comprises a polymer solution or polymer melt the polymer solution is evaporated or the polymer melt is maintained and then cooled concurrently with the ordering of the particles.

Highly conductive ordered ion exchange membranes

An evaporation device for increasing evaporation from a surface of a body of liquid, comprises at least one evaporation element having at least one evaporation surface wettable by the liquid and at least partially exposable to wind when wetted, so as to allow evaporation of the liquid from the evaporation surfaces whereby the total evaporation area of the surface of the body of liquid is increased.

Evaporation device

The invention provides a polymeric netting for use as an ion-conducting ser in an electrodialysis stack having charged groups incorporated in a in polymeric coating applied thereto, imparting to the spacer an average ion exchange capacity of at least 0.25 meq/gr.

Ion-exchange spacer and processes for the preparation thereof

The invention concerns heterogeneous ion exchange membranes used in electrodialysis which have anti-polarization and anti-fouling properties. The heterogeneous membranes of the invention comprise, in addition to ion-exchange particles embedded in the matrix, a layer of at least one hydrophilic cross-linked polymer bearing fixed electric charges. Alternatively, the heterogeneous membranes of the invention have a matrix which is itself made of at least one hydrophilic cross-linked polymer.

Ion exchange membranes

A supported, mechanically stable bipolar membrane for electrodialysis having a cation-exchange layer on one side and an anion-exchange layer on the other side of a single sheet of woven fabric. The cation exchange layer is heterogeneous, the anion exchange layer is homogeneous and the two are interlocked. A process of making such bipolar membranes is described. The bipolar membrane may be fabricated into electrodialysis cells in which two membranes are joined along their edges.

Supported, mechanically stable bipolar membrane for electrodialysis

Water softening by a combination of electrodialysis and calcium carbonate precipitation. The hard feed water or alternatively recycled soft water is rendered alkaline and is then subjected to a treatment by which precipitation of calcium carbonate is induced. One way of bringing about such precipitation consists in passing the alkaline water across a cake of calcium carbonate crystals having a size not exceeding 100 microns, deposited on a filter and being in an at least fifty fold excess over the amount of calcium carbonate to be precipitated.

Electrodialysis reversal process and apparatus with bipolar membranes

Process for softening hard water by precipitation of calcium carbonate. The hard water is rendered alkaline, e.g. by the addition of sodium hydroxide, and is then contacted with a large excess of calcium carbonate crystals whose size does not exceed 100 microns, whereby precipitation occurs within a short contact time of the order of 2-60 seconds. Upon separation of soft water from calcium carbonate the bulk of the latter is recirculated and excessive amounts are removed.

Water softening process

There are provided integrated modules for use in electrodialysis devices, which modules comprise a plurality of unit cells each of which consists of a cation specific membrane, a spacer and an anion specific membrane, said membranes being sealed along the edges of the cell, a spacer being provided between consecutive cells serving for sealing along the edges, an outlet being provided for the brine, outlets of individual cells being arranged as common outlet, a plurality of unit cells being confined in a frame which is provided with an outlet for said cells, each frame being provided with sealing means towards the next such frame. There are also provided electrodialysis stacks comprising a plurality of such modules.

Modular electrodialysis device

The invention provides a method for the performance of selective electrodialytic separation of a first group of charged ions from a solution containing other charged ions having the same sign and optionally the same valence as said first group comprising applying a current to an electrodialysis unit comprising at least one thin, dense, non-porous charged electrodialysis membrane made of water-insoluble hydrophobic polymeric material, containing covalently bound ionizable groups, wherein said membrane separates at least one diluting compartment from at least one concentrating compartment in said unit and wherein said membrane is in the form of a polymeric matrix optionally supported on a porous support and having a preselected dielectric constant and composition adapted to induce selective ion disassociation of said first group of charged ions whereby there is achieved a substantial ion migration of said selected ion group and its preferential transference across said membrane at a fraction larger than its relative concentration in said solution. The invention also provides a selective electrodialysis unit per carrying out said method.

Method and apparatus for the performance of selective electrodialysis

The invention provides a process for the separation, by electrodialysis, of a mixed aqueous solution, containing an essential amino acid and a derivative of that acid as components therof, wherein one of said components is in charged form and the other of said components is in amphoteric form, into at least two separate product solutions, of acid and derivative respectively, of which at least one product solution contains highly pure product obtained at high quantitative yield, comprising providing an electrodialysis stack, continuously introducing a feed solution containing an essential amino acid and derivative thereof to be separated into feed cells of the stack, adjusting the flow rate and concentration of the solution and the electric current density applied to values adapted to create concentration polarization conditions adjacent to the membranes in the feed cell thereby accumulating a high local concentration of protons upon the surface of the anion exchange membranes, and a high local concentration of hydroxyl ions upon the cation exchange membranes and maintaining the pH of the bulk solution in the feed cells in a range of between 4-8, irrespective of the isoelectric point of the amphoteric component, in order to adjust for pH changes of the bulk solution occurring due to unequal rates of water dissociation at the cation and anion exchange membranes.

Electrodialysis process for the separation of essential amino acids from

The invention provides a process for the separation, by electrodialysis, of a mixed aqueous solution containing a non-essential amino acid and a derivative of that acid in ionic form, into at least two separate product solutions of acid and derivative respectively, of which at least one solution contains highly pure product obtained at high quantitative yield, comprising providing an electrodialysis stack, continuously introducing a feed solution containing a non-essential amino acid and derivative thereof to be separated into feed cells of the stack, adjusting the flow rate and concentration of the solution and the electric current density applied to values adapted to create concentration polarization conditions adjacent to the membranes in the feed cells thereby accumulating a high local concentration of protons upon the surface of the anion exchange membranes, and a high local concentration of hydroxyl ions upon the cation exchange membranes and maintaining the pH of the bulk solution in the feed cells in a range of between 4-8, irrespective of the isoelectric point of the amino acid, in order to adjust for pH changes of the bulk solution occurring due to unequal rates of water dissociation at the cation and anion exchange membranes.

Electrodialysis process for the separation of non-essential amino acids

According to the present invention there is provided an improved electrodialysis device comprising an electrodialysis stack with an anode compartment adjacent one end of the stack, a cathode compartment adjacent the other end of the stack, said electrode compartments being connected with each other by means of conduits, means being provided for circulating a slurry of carbon particles between the two electrode compartments. The slurry comprises finely powdered active carbon in an electrolyte, either by itself or in combination with finely powdered ion-exchange resin. The electrode compartments can be provided with inserts defining constrictions for the outflow of the slurry at the lower part of the inserts thus establishing a higher concentration of the particles at the lower part of the compartment. The invention further relates to an eletrodialysis process wherein a slurry of carbon particles is circulated between the electrode compartments.

Growing community of inventors

Rehovot, Israel

Ora Kedem