Westinghouse Electric Corporation

Clearwater Systems Corporation

Silrec Systems, Inc.

Karl Moeglich

Graham L Hodgetts

An improved method and apparatus for continuously agglomerating solids of colloidal size or larger suspended in a liquid is disclosed. The process comprises passing the liquid between spaced electrode plates in the presence of a fluidized bed of conductive particles, and subjecting said liquid suspension to an electric field from alternating current applied across said electrodes through the conductive particles of said bed. The turbulence of the particles in said bed has been found to improve conductivity and current efficiency, minimize electrode erosion, and by a mechanical, scrubbing action of the bed particles, minimize fouling or scaling of the electrodes so that the suspending forces of said solids are rapidly and efficiently broken. The agglomerated solids may then be separated from the liquid by conventional means such as skimming, settling, flotation and the like.

Water purification method and apparatus

A membrane assembly, useful as a membrane in electrodialytic and electrolytic cells, is made by holding together a plurality of thin layers of membrane material under pressure and with boundary layers of liquid covering their major surfaces. Such membrane assemblies allow the passage therethrough of ions when an electric potential difference is impressed across the membrane assembly but effectively bar the passage of water and gases. They also bar or limit ionic and salt mass transfer in the absence of such a potential difference (during non-use of the cell). They make excellent long lasting cell components, capable of being manufactured simply and economically from any of a variety of membrane materials to produce membranes of desired properties.

Method and apparatus for lessening ionic diffusion

Oxidizable contaminants in waters, such as feed waters and waste waters wherein they are present in relatively large or small proportions, are removed therefrom by alternating current electrolysis in an electrolytic cell containing catalyst-containing particles, the catalyst of which is an oxidation catalyst such as MnO.sub.2, Cr.sub.2 O.sub.3, Bi.sub.2 O.sub.3, or PbO.sub.2. The process and apparatus of the invention are especially useful for the removal of difficultly oxidizable impurities, such as phenol, from dilute aqueous solutions or dispersions. Included within the invention is the improved removal of such impurities by sequential treatments in accordance with the described processes. Also disclosed are the production of hydrogen peroxide by alternating current electrolysis of water; the oxidation of phenolic compounds; the reactivation of at least partially inactivated carbon adsorbents by subjection to alternating current; and the concentration of chemical impurities from activated carbon by adsorption on particles thereof, followed by desorption by application by alternating current.

Process and apparatus for removal of contaminants from water

An improved method and apparatus for continuously agglomerating solids of colloidal size of larger suspended in a liquid is disclosed. The process comprises passing the liquid between spaced electrode plates in the presence of a fluidized bed of conductive particles, and subjecting said liquid suspension to an electric field from alternating current applied across said electrodes through the conductive particles of said bed. The turbulence of the particles in said bed has been found to improve conductivity and current efficiency, minimize electrode erosion, and by a mechanical, scrubbing action of the bed particles, minimize fouling or scaling of the electrodes so that the suspending forces of said solids are rapidly and efficiently broken. The agglomerated solids may then be separated from the liquid by conventional means such as skimming, settling, flotation and the like.

Water purification method

A vessel is described for facilitating the removal of difficultly oxidizable impurities such as phenol and/or polychlorinated biphenyl from dilute aqueous solutions or dispersions. The vessel contains stacked, packed beds having characteristics of alternating high and low electrical conductivity with separately controlled pairs of electrodes for the two alternate types of beds. An aqueous solution containing contaminants is admitted to the vessel and passed through the successive beds wherein the solution or dispersion is subjected to an alternating current field for decomposition of the contaminants in the high resistivity beds and oxidization thereof in the lower resistivity beds by hydrogen peroxide produced by alternating current electrolysis of water. The preferred electrodes are hollow and water cooled. In addition, the bed is jacketed and cooling water is circulated through the jacket to maintain a more efficient, lower process temperature. The bed having lower resistivity includes conductive particles which may be graphite, and may include activated carbon or equivalent material. Said bed also contains non-conductive particles such particles being coated with catalysts. The catalyst may be an oxidation catalyst, such as the oxides of the metals of Groups IVa, Va, VIb, and VIIb, and specifically preferred are MnO.sub.2, Cr.sub. 2 O.sub.3, Bi.sub.2 O.sub.3 or PbO.sub.2. In the alternative, the catalyst may be a reduction catalyst such as oxides of nickel, iron and oxides of other Group VIII metals. The highly resistive bed is packed with said non-conductive particles only.

Apparatus for removal of contaminants from water

A sorbent particulate material, such as a metal hydroxide-coated sawdust, is made by passing a direct electric current between an anode of a metal capable of forming a flocculent hydroxide and a cathode in a turbulent electrolyte containing the dispersed particulate material, so as to form a metal hydroxide and deposit it on such material. Also described are filters made from the sorbent particulate material and processes of filtering or otherwise removing undesired components from liquid media by means of such product.

Sorbent particulate material and manufacture thereof

The present invention relates to a method of electrochemically removing silver in the form of AgO from a photographic fixer solution containing silver ions without destroying the utility of the solution comprising the steps of applying alternating current having a frequency of between about 0.5 Hz and 800 Hz and a current density of between about 0.1 and 20 amperes per square inch across electrodes immersed in said solution to cause AgO to precipitate at the electrodes. The method can also be practiced above the range of about 20 amperes per square inch at the cost of destroying the utility of the solution. The method can also be used to remove silver in the form of AgO from other solutions.

Electrochemical process utilizing alternating current for recovery of

A method of electrolytically removing silver from a photographic fixer solution comprising the steps of placing the photographic fixer solution in a cell having an anode chamber and a cathode chamber, with said chamber being separated by a diaphragm having a pore size of between about 1.0 microns to 500 microns and applying a direct current across the anode and cathode to create a current density of between about 0.001 and 5 amperes per square inch at the cathode to thereby cause argentic oxide to precipitate at the cathode and an equivalent amount of elemental sulfur to precipitate at the anode. The cell is preferably maintained at a temperature of between about 20.degree. C. and 60.degree. C. The cell can be operated as a flow cell by maintaining a hydraulic head between the chambers to determine the flow across the diaphragm. When the cell is operated as a flow cell, a minimum specific amount of photographic fixer must be conveyed to the cell to prevent oxidation of sulfur and escape of SO.sub.2 gas.

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Williamsville, NY, United States of America

Karl Moeglich