US3663407A - Treatment of an ultrafiltrate derived from an electrodeposition process by reverse osmosis - Google Patents

Treatment of an ultrafiltrate derived from an electrodeposition process by reverse osmosis Download PDF

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US3663407A
US3663407A US155042A US3663407DA US3663407A US 3663407 A US3663407 A US 3663407A US 155042 A US155042 A US 155042A US 3663407D A US3663407D A US 3663407DA US 3663407 A US3663407 A US 3663407A
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membrane
water
reverse osmosis
bath
solute
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Frederick M Loop
Frank C Bosworth
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PPG Industries Inc
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PPG Industries Inc
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/58—Multistep processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D13/00—Electrophoretic coating characterised by the process
    • C25D13/22—Servicing or operating apparatus or multistep processes
    • C25D13/24—Regeneration of process liquids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025—Reverse osmosis; Hyperfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/145—Ultrafiltration

Definitions

  • This invention relates to the use of reverse osmosis to treat ultrafiltrate derived from an electrodeposition process in order to provide a relatively more pure process efiluent and/or to provide rinse water to the process of relatively higher purity.
  • Electrodeposition has become a widely commerciallyaccepted industiral coating technique.
  • the coatings achieved have excellent properties for many applications and electrodeposition results in a coating which does not run or wash ofi during baking.
  • Virtually any conductive substrate may be coated by electrodeposition.
  • metal substrates including metals such as iron, steel, copper, zinc, brass, tin, nickel, chromium and aluminum, as well as other metals and pretreated metals.
  • lmpregnated paper or other substances rendered conductive under the conditions of the coating process may also be employed as substrates.
  • the articles to be electrocoated are immersed in an aqueous dispersion of a solubilized, ionized, film-forming material such as a synthetic organic vehicle resin.
  • An electric current is passed between the article to be coated, serving as an electrode, and a counter-electrode to cause deposition of a coating of the vehicle resin on the articles.
  • the articles are then withdrawn from the bath, usually rinsed, and then the coating either air-dried or baked in the manner of a conventional finish.
  • Ultrafiltration of an electrodepositable composition selectively removes low molecular weight materials from the bath composition.
  • This selective filtration process removes excess counter-ion and thus serves as a method of conventional bath control, but in addition this method further removes other excess materials or contaminants from the bath, thus permitting more complete control of the baths constituents than has heretofore been possible.
  • the ultrafiltrate that is, the efiluent from the process, being essentially vehicle resin free, may be employed as rinse water in a manner so that the rinse water returns to the electrodeposition bath, returning dragout solids previously lost to the electrodeposition bath without adding substantial amounts of additional water to the system, thus overflowing the electrodeposition bath.
  • ultrafiltrate is substantially purer aqueous media than the electrodeposition bath in that it is substantially free of high molecular weight resinous materials and pigments and the like, it does contain anionic, cationic and non-ionic materials from the paint in most instances in a ratio proportional to their concentration in the water phase of the paint.
  • ultrafiltrate depending on the composition of the electrodeposition bath, can possibly contain amines, alkali metal ions, phosphates, chromates, sulfates, solvents, salt, and carbon dioxide, as well as other constituents.
  • ultrafiltrate can be subjected to reverse osmosis separation, providing a concentrate or retentate containing a substantial portion of the anionic, cationic and non-ionic materials in the ultrafiltrate, while passing a substantially purer aqueous efiluent.
  • This allows for substantial refinements and improvements in the electrodeposition process.
  • Reverse osmosis concentrates the deleterious materials for disposal by other means while passing a substantially purer effluent to drain.
  • ultrafiltrate employed as rinse water
  • the system must be run open, passing ultrafiltrate to drain for bath control, thus requiring the addition of alternative sources of water such as deionized water for rinsing.
  • Reverse osmosis of ultrafiltrate provides a more continuous supply of aqueous media for rinsing of substantially higher purity than ultrafiltrate while removing contaminants or deleterious materials in the concentrate or retentate.
  • rinsing employing the efiluent from reverse osmosis treatment it may be accomplished in such a way that the effluent and drag-out are either collected separate from the bath or immediately returned to the bath.
  • the process of the invention is a method of bath control, it may be desirable in order to maintain or change the composition of the bath to intermittently or continuously remove at least a portion of the efiluent of either the ultrafiltration process or the subsequent reverse osmosis process of the system.
  • the rinsing of drag-out may be intermittently conducted with tap water or preferably deionized water, either separate from the bath or in the manner so that this rinse returns to the bath.
  • a mixture of reverse osmosis eflluent and other water or even ultrafiltrate may be employed as rinsing media.
  • 'Electrodeposition bath 1 from which films are deposited uses suitable apparatus (not shown).
  • a portion of the bath may be continuously or intermittently withdrawn through an outlet in valve 2 and passed through line 3 to an ultrafilter 4.
  • free counter ions and counter ions present as low molecular weight salts for example, carbonate, as Well as other low molecular Weight species, if present, are separated from the vehicle resin through ultrafiltration membrane 19.
  • the concentrate or retentate comprises an aqueous dispersion of vehicle resin, pigment and other high molecular weight components of the bath composition.
  • the ultrafiltrate is removed from the ultrafilter passing through line 5 through the use of valve 6 while the concentrate or retentate is returned to the bath through line 15 and valve 16.
  • the ultrafiltrate may be directed either unidirectionally or proportionally in either an intermittent or continuous fashion to drain 7 or to a reverse osmosis unit 21.
  • water, free counter ions, counter ions present as low molecular weight salts, for example, carbonate, as well as other low molecular weight species are retained in the concentrate or retentate while there passes through the reverse osmosis membrane substantially purer aqueous media than enters the reverse osmosis unit through line 20.
  • the concentrate or retentate may be passed to drain through line 23 through the use of valve 28 or may be returned to the electrodeposition bath through line 29, or even through the use of appropriate piping may be used as a first stage rinse. All the efi luent from the reverse osmosis process is passed through valve 27 and line 24, either unidirectionally or proportionately in either intermittent or continuous fashion to drain, for use as rinse material or for direct return to the electrodeposition bath.
  • valves 9 and 13 likewise accommodate the intermittent or proportional use of Water 11 or 12 rather than reverse osmosis eflluent for rinsing.
  • valves 6 and 26 allow for the proportional or intermittent use of ultrafiltrate for rinsing.
  • Line 17 allows for the return of ultrafiltrate or reverse osmosis effiuent to the bath if and when desired.
  • Ultrafiltration is a process which separates materials below a given molecular Weight size from the high molecular weight components in an electrodeposition bath. With properly selected membranes, this treatment does not remove any product or desirable resin from the paint or the tank. It does remove low molecular weight anionic, cationic and non-ionic materials from the paint in a ratio to their concentration in the water-phase of the paint.
  • lUltrafiltration may be defined as a method of concentrating solute while removing solvent, or selectively removing solvent and low-molecular weight solute from a significantly higher molecular weight solute. From another aspect, it is a process of separation whereby a solution containing a solute of molecular dimensions significantly greater than the solvent is depleted of solute by being forced under a hydraulic pressure gradient to flow through a suitable membrane.
  • the first definition is the one which most fittingly describes the term ultrafiltration as applied to an electrodeposition bath.
  • Ultrafiltration thus encompasses all membrane-moderated, pressure-activated separations wherein solvent or solvent and smaller molecules are separated from modest molecular weight macromolecules and colloids.
  • the term ultrafiltration is generally broadly limited to describing separations involving solutes of molecular dimensions greater than about ten solvent molecular diameters and below the limit of resolution of the optical microscope, that is, about 0.5 micron. In the present process, water is considered the solvent.
  • the basic ultrafiltration process is relatively simple. Solution to be ultrafiltered is confined under pressure, utilizing, for example, either a compressed gas or liquid pump in a cell, in contact with an appropriate filtration membrane supported on a porous support. Any membrane or filter having chemical integrity to the system being separated and having the desired separation characteristic may be employed. Preferably, the contents of the cell should be subjected to at least moderate agitation to avoid accumulation of the retained solute on the membrane surface with the attendant binding of the membrane. Ultrafiltrate is continually produced and collected until the retained solute concentration in the cell solution reaches the desired level, or the desired amount of solvent or solvent plus dissolved low molecular weight solute is removed.
  • a suitable apparatus for conducting ultrafiltration is described in U.S. Pat. No. 3,494,465, which is hereby incorporated by reference.
  • ultrafiltration membrane There are two types of ultrafiltration membrane.
  • One is the microporous ultrafilter, which is a filter in the traditional sense, that is, a rigid, highly-voided structure containing interconnected random pores of extremely small average size.
  • solvent in the case of electrodeposition, water
  • z flows essentially viscously under a hydraulic pressure gradient, the flow rate proportional to the pressure difierence, dissolved solutes, to the extent that their hydrated molecule dimensions are smaller than the smallest pores within the structure, Will pass through, little impeded by the matrix. Larger size molecules, on the other hand, will become trapped therein or upon the external surface of the membrane and will thereby be retained.
  • microporous ultrafilters are inherently susceptible to internal plugging or fouling by solute molecules whose dimensions lie within the pore size distribution of the filter, it is preferred to employ for a specific solute a microporous ultrafilter whose mean pore size is significantly smaller than the dimensions of the solute particle being retained.
  • the difiusive ultrafilter is a gel membrane through which both solvent and solutes are transported by molecular ditfusion under the action of a concentration or activity gradient.
  • solute and solvent migration occurs via random thermal movements of molecules within and between the chain segments comprising the polymer network.
  • Membranes prepared from highly hydrophilic polymers which swell to eliminate standard water are the most useful diffusive aqueous ultrafilter membranes. Since a diffusive ultrafilter contains no pores in the conventional sense and since concentration within the membrane of any solute retained by the membrane is low and time-independent, such a filter is not plugged by retained solute, that is, there is no decline in solvent permeability with time at a constant pressure. This property is particularly important for a continuous concentration or separation operation. Both types of filters are known in the art.
  • the presently preferred ultrafilter is an anisotropic membrane structure such as illustrated in FIG. 1.
  • This structure consists of an extremely thin, about one-tenth to about ten micron layer, of a homogeneous polymer 1 supported upon a thicker layer of a microporous opencelled sponge 2, that is, a layer of about 20 microns to about 1 millimeter, although this dimension is not critical.
  • this membrane can be further supported by a: fibrous sheet, for example, paper, to provide greater strength and durability.
  • fibrous sheet for example, paper
  • Membranes useful in the process are items of commerce and can be obtained by several methods.
  • One general method is described in Belgian Pat. No. 721,058.
  • This patent describes a process which in summary comprises (a) forming a casting dope of the polymer in an organic solvent, (b) forming a film of the casting dope, and (c) preferentially contacting one side of said film with a diluent having high compatibility with the casting dope to efiect precipitation of the polymer immediately upon coating the cast film with the diluent.
  • Membranes can be typically prepared from thermoplastic polymers such as polyvinyl chloride, polyacrylonitrile, polysulfones, poly(methyl methacrylate), polycarbonates, poly(n-butyl methacrylate), nylons, as Well as a large group of copolymers formed from any of the monomeric units of the above polymers, including Polymer 360, a polysulfone copolymer. Cellulose materials such as cellulose acetate may also be employed as membrane polymers.
  • Diafiow membrane ultrafilter PM-30 the membrane chemical composition of which is polysulfone copolymer, Polymer 360, and which has the following permeability characteristics:
  • the membrane is chemically-resistant to acids (HCl, H 50 H PO all concentrates), alkalis, high phosphate buffer and solutions of common salts as well as concentrated urea and guanadine hydrochloride.
  • the membrane is solvent-resistant to alcohol, acetone and dioxane.
  • the membrane is not solvent-resistant to dimethylformamide or dimethylsulfoxide. This membrane is hereinafter referred to as Membrane A.
  • Dorr-Oliver XPA membrane the membrane chemical composition of which is Dynel (an acrylonitrile-vinyl chloride copolymer) and which has the following permeability characteristics:
  • Membrane B This membrane is hereinafter referred to as Membrane B.
  • Dorr-Oliver BPA membrane the membrane chemical composition of which is phenoxy resin (polyhydroxy ether) and which has the following permeability characteristics:
  • This membrane is hereinfater referred to as Membrane C.
  • the microporous ultrafilters are generally isotropic structures, thus flow and retention properties are inde pendent of flow direction. It is preferred to use an ultrafilter which is anisotropic in its microporous membrane structure, FIG. 2. In such a membrane, the pore size increases rapidly from one face to the other. When the fine textured side 4 is used in contact with the feed solution, this filter is less susceptible to plugging since a particle which penetrates the topmost layer cannot become trapped in the membrane because of the large pore size 5 in the substrate.
  • the process of the invention may be operated as either a batch or a continuous process.
  • batch selective filtration or batch ultrafiltration a finite amount of material is placed in a cell which is pressurized. A solvent and lower molecular weight solutes are passed through the membrane. Agitation is provided by a stirrer, for example, a magnetic stirrer. Obviously, this system is best used for small batches of material.
  • a continuous selective filtration process is preferred. Using this technique, material is continuously recirculated under pressure against a membrane or series of membranes through interconnecting flow channels, for example, spiral flow channels.
  • the ultrafiltration process may be conducted as either a concentration process or a diafiltration process.
  • Concentration involves removing solvent and low molecular weight solute from an increasingly concentrated retentate. Filtration flow rate will decrease as the viscosity of the concentrate increases.
  • Diafiltration is a constant volume process whereby the starting material is connected to a reservoir of pure solvent, both of which are placed under pressure simultaneously. Once filtration begins, the pressure source is shut off in the filtration cell and, thus, as the filtrate is removed, an equal volume of new solvent is introduced into the filtration cell to maintain the pressure balance.
  • the configuration of the filter may vary widely and is not limiting to the operation of the process.
  • the filter or membrane may, for example, be in the form of sheets, tubes or hollow fiber bundles, among other configurations.
  • C is the initial solute concentrate
  • C is the final solute concentration of the retentate
  • V is the volume of solute delivered to the cell (or the volume of the filtrate collected)
  • V is the initial solution volume (which remains constant).
  • Electrodepositable compositions while referred to as solubilized, in fact are considered a complex solution, dispersion or suspension or combination of one or more of these classes, in water, which acts as an electrolyte under the influence of an electric current. While, no doubt, in some circumstances the vehicle resin is in solution, it is clear that in some instances and perhaps in most the vehicle resin is a dispersion which may be called a molecular dispersion of molecular size between a colloidal suspension and a true solution.
  • the typical industrial electrodepositable composition also contains pigments, crosslinking resins and other adjuvants which are frequently combined with the vehicle resin in a chemical and physical relationship.
  • the pigments are usually ground in a resin medium and are thus wetted with the vehicle resin.
  • an electrodepositable composition is complex in terms of the freedom or availability with respect to removal of a component or in terms of the apparent molecular size of a given vehicle component.
  • ultra-filtration comprises subjecting an electrodepositable composition, especially after it has been employed in a coating process, which inherently causes contaminants and other low molecular weight materials to accumulate in the bath, such as metal pretreatment chemicals, water, absorbed CO (either dissolved, or, more likely, combined as an aminic salt or carbonate), neutralizing agent, organic solvent and ions such as chromate, phosphate, chloride and sulfate, for example, to an ultrafiltration process employing an ultrafilter, preferably a diffusive membrane ultrafilter selected to retain the solubilized vehicle resin while passing water and low molecular weight solute, resin While passing water and low molecular weight solute, especially those with passing water and low molecular weight solute, especially those with a molecular weight below about 500.
  • an ultrafilter preferably a diffusive membrane ultrafilter selected to retain the solubilized vehicle resin while passing water and low molecular weight solute, resin While passing water and low molecular weight solute, especially those with passing water and low molecular weight solute
  • the filters discriminate as to molecular size rather than actual molecular weight, thus, these molecule weights merely establish an order of magnitude rather than a distinct molecular weight cut-01f.
  • the retained solutes may, in fact, be colloidal dispersions or molecular dispersions rather than true solutes.
  • a portion of the electrodepositable composition may be continuously or intermittently removed from the electrodeposition bath and passed under pressure created by a pressurized gas or by means of pressure applied to the contained fluid in contact with the ultrafilter.
  • the egress side of the filter may be maintained at a reduced pressure to create the pressure difference.
  • the pressures necessary are not severe.
  • the maximum pressure in part, depends on the strength of the filter.
  • the minimum pressure is that pressure required to force water and low molecular weight solute through the filter at a measurable rate.
  • the operating pressures are between about and 150 p.s.i., preferably between about 25 and 75 p.s.i.
  • the ultrafilter should have an initial flux rate, measured with the composition to be treated of at least about 3 gaL/ftfi/day (24 hours) and preferably at least about 4.5 gal./ft. /day.
  • the bath composition should be in motion at the face of the filter to prevent the retained solute from impeding the flow through the filter. This may be accomplished by mechanized stirring or by fluid flow with a force vector parallel to the filter surface.
  • the retained solutes comprising the vehicle resin are then returned to the electrodeposition bath.
  • the concentrate may be reconstituted by the addition of water either before entry to the bath or by adding water directly to the bath.
  • Electrodepositable resins are known and can be employed to provide the electrodepositable compositions utilized in the practice of this invention.
  • Virtually any water-soluble, water-dispersible or water-emulsifiable polyacid or polybasic resinous material can be electrocoated and, if film-forming, provides coatings which may be suitable for certain purposes. Any of such electrodepositable compositions is included among those which may be employed in the present invention, even though the coating obtained may not be entirely satisfactory for certain specialized uses.
  • Electrodepositable compositions while referred to as solubilized, in fact are considered complex solutions, dispersions or suspensions, or a combination of one or more of these classes in water, which acts as an electrolyte under the influence of an electric current.
  • the vehicle resin is in solution, it is clear that in some instances, and perhaps in most, the vehicle resin is a dispersion which may be called a molecular dispersion of molecular size between a colloidal suspension and a true solution.
  • a molecular dispersion of molecular size between a colloidal suspension and a true solution.
  • Numerous such resins are described in U.S. Pats. Nos. 3,230,162; 3,441,489; 3,422,044; 3,403,088; 3,369,983; 3,366,563; 3,3 82,165 and British Pat. No. 1,132,267 as well as other patents to be found in Class 204-, sub-class 181, of the US. Patent Oflice.
  • Electrodeposition vehicle resins are synthetic polycarboxylic acid resinous materials; however, polyacids other than polycarboxylic acids are known in the art as electrodepositable resins. Likewise, polybasic resins may be employed.
  • the polyacids are anionic in nature and are dispersed or dissolved in water with alkaline metals such as amine or alkaline metal hydroxides and when subjected to electric current they migrate to the anode.
  • alkaline metals such as amine or alkaline metal hydroxides
  • Polybasic resins solubilized by acids are cationic in nature and when these resins are Water-dispersed or solubilized with an acid, the material is deposited on the cathode under an electric current.
  • most electrodepositable compositions are a complex mixture
  • most commercially-utilized electrodepositable compositions are a complex mixture of either the anionic or cationic resins described above formulated with adjuvants such as pigments, solvents and surfactants, crosslinking resins and the like.
  • the ultrafiltrate is subjected to reverse osmosis.
  • Ultrafiltration can be deemed a separation process that is separating large molecules from smaller molecules.
  • Reverse osmosis is a purification process, that is, a process to produce a substantially purer aqueous effluent.
  • Osmosis may be described as the migration of pure water through a semipermeable membrane spontaneously into a concentrated solution until equilibrium. The head developed at equilibrium is defined as osmotic pressure.
  • Reverse osmosis involves applying a pressure greater than the osmotic pressure to cause water to flow in a reverse manner through the semi-permeable membrane.
  • a pressure exceeding the osmotic pressure is applied to the concentrated solution to cause flow from the concentrated side to the pure side.
  • Typical operating pressures are at least several hundred p.s.i., but always greater than the osmotic pressure of the system.
  • Membranes can be typically prepared from thermoplastic polymers such as polyvinyl chloride, polyacrylonitrile, polysulfones, poly(methyl inethacrylate), polycarbonates, poly(n-butyl methacrylate), nylons, as well as a large group of copolymers formed from any of the monomeric units of the above EXAMPLE I
  • the electrodepositable composition utilized in this ex ample was prepared as follows:
  • a pigment paste was formulated as follows:
  • PASTE A Parts by weight 20 percent maleinized" oil (total solids content 97.6%) Diethylamine 20 percent maleic anhydrlde, 80 percent linseed 011, male inized oil having a viscosity of 100,000 centipoises.
  • Dispersing agent combination oil-soluble sulfonate and non-ionic surfactant
  • Wico 912 1.48
  • the vehicle resin employed in formulating Composition C was comprised of a maleinized tall oil fatty acid ester of a styrene-allyl alcohol copolymer of 1100 molecular weight and a hydroxyl functionality of comprising 38.5 percent of the copolymer, 55.5 percent tall oil fatty acids, and 6.0 percent maleic anhydride as a 100 percent solids vehicle having an intrinsic viscosity Of 120,000 centipoises and an acid number of 40.6.
  • COMPOSITION C Vehicle resin above at 100 percent solids content 1319.6
  • Wetting agent sorbitan monolaurate
  • Hexakis (methoxymethyl)melamine 159.8
  • Ethyl Cellosolve 67.0 were mixed 10 minutes and there was added: Composition B 1477.4
  • composition was again mixed 10 minutes and there was added:
  • composition was again mixed 10 minutes and there was added:
  • Composition C was reduced to produce Composition D (below):
  • Composition D had the following properties:
  • the above composition was utilized to electrocoat articles through numerous turnovers, the bath being controlled by ultrafiltration utilizing Membrane C set forth above at 50 p.s.i.
  • the ultrafiltrate was then subjected to treatment by reverse osmosis utilizing a Permasep Permeator Membrane having a hollow fiber configuration and characterized by the following parameters at 400 p.s.i., 50 percent conversion:
  • Electrodepositable compositions such as those hereinabove described, can be substituted for those of the examples Likewise, various ultrafilters, reverse osmosis systems, and method variations may be employed to obtain the improvements hereinabove described.
  • aqueous electrodeposition bath which comprises ionically solubilized synthetic organic resin
  • steps comprising subjecting at least a portion of said electrodeposition bath to an ultrafiltration process wherein the ultrafiltration membrane passes a first aque- 11 ous effluent comprising water and solute of substantially lower molecular size than the solubilized resin, returning retentate from the ultrafiltration process to the electroposition bath, subjecting said first aqueous efliuent to a reverse osmosis process whereby a second, purer aqueous effiuent is produced.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4948192A (ja) * 1972-07-19 1974-05-10
JPS4994580A (ja) * 1973-01-17 1974-09-07
US4269208A (en) * 1978-08-28 1981-05-26 Koering Dale J Electroplating apparatus
EP0156341A3 (en) * 1984-03-28 1987-01-07 Ppg Industries, Inc. Treatment of ultrafiltrate by electrodialysis
EP0891950A1 (de) * 1997-07-17 1999-01-20 PPG Industries Lacke GmbH Verfahren zur Aufbereitung von lösemittelhaltigen Prozessflüssigkeiten
US20060000717A1 (en) * 2004-06-30 2006-01-05 Taiwan Semiconductor Manufacturing Co., Ltd. Method and apparatus for stabilizing plating film impurities
US20230295017A1 (en) * 2020-03-24 2023-09-21 Organo Corporation Water recovery system and water recovery method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60137489A (ja) * 1983-12-26 1985-07-22 Ajinomoto Co Inc 廃液の処理法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE758366A (fr) * 1969-11-03 1971-04-16 Pressed Steel Fisher Ltd Procede d'enduction d'articles par depot electrolytique
BE759416A (fr) * 1969-11-25 1971-05-25 Ppg Industries Inc Procede d'echange d'ions d'un ultrafiltrat provenant d'un bain de depotelectrolytique

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4948192A (ja) * 1972-07-19 1974-05-10
JPS5330278B2 (ja) * 1972-07-19 1978-08-25
JPS4994580A (ja) * 1973-01-17 1974-09-07
US4269208A (en) * 1978-08-28 1981-05-26 Koering Dale J Electroplating apparatus
EP0156341A3 (en) * 1984-03-28 1987-01-07 Ppg Industries, Inc. Treatment of ultrafiltrate by electrodialysis
EP0891950A1 (de) * 1997-07-17 1999-01-20 PPG Industries Lacke GmbH Verfahren zur Aufbereitung von lösemittelhaltigen Prozessflüssigkeiten
WO1999003786A1 (en) * 1997-07-17 1999-01-28 Ppg Industries Lacke Gmbh Method of treating solvent-containing process liquids
US20060000717A1 (en) * 2004-06-30 2006-01-05 Taiwan Semiconductor Manufacturing Co., Ltd. Method and apparatus for stabilizing plating film impurities
US7481910B2 (en) * 2004-06-30 2009-01-27 Taiwan Semiconductor Manufacturing Co., Ltd. Method and apparatus for stabilizing plating film impurities
US20230295017A1 (en) * 2020-03-24 2023-09-21 Organo Corporation Water recovery system and water recovery method

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FR2143018B1 (ja) 1981-12-31
DE2229677A1 (de) 1972-12-28
FR2143018A1 (ja) 1973-02-02
AU4200872A (en) 1974-01-31
IT959036B (it) 1973-11-10
GB1391350A (en) 1975-04-23
BR7203958D0 (pt) 1973-05-10
DE2229677B2 (de) 1981-07-30
BE785118A (fr) 1972-12-20
JPS541496B1 (ja) 1979-01-25
CA961002A (en) 1975-01-14
AU444583B2 (en) 1974-01-31

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