Abstract: A process for removing and preventing iron contamination of water treatment solids which tend to become iron fouled which comprises cyclically treating said water treatment solids with an aqueous solution containing an effective amount of:(a) a reducing agent;(b) a chelating agent;with a pH of said treating solution having been adjusted to within a range of about 4-6.

Abstract: The invention relates to improved methods for regenerating the exhausted anion and cation exchange resins in a mixed bed demineralizer system. The exhausted bed of resin is directed into a separation vessel which contains a buffer volume of anion and cation resins remaining therein from the previous regeneration cycle. The resin in the separation vessel is classified into an upper anion resin layer, a lower cation resin layer and an intermediate layer of intermingled anion and cation resin. The cation resin is transferred from the bottom of the separation vessel to a cation regeneration vessel through a cation transfer conduit having isolation valves associated with the respective ends thereof. The resin transfer is terminated upon the detection of anion resin in the transfer conduit, at which time the isolation valves are closed so as to isolate the bulk of the intermingled anion and cation resin layer in the cation transfer conduit.

Abstract: A process and apparatus are provided for recovering metals from dilute solution utilizing ion exchange and, optionally, electrolytic recovery. Ammonium salt regeneration solutions for use in the process and apparatus are also provided. In one aspect, the invention provides a closed loop process and apparatus whereby metals may be recovered from spent electroplating rinse solutions for reuse in the electroplating bath with essentially no generation of waste.

Abstract: A method and apparatus is provided for holding first material along with less dense material in substantially separate layers and for effecting removal of at least some of the second material to a location displaced from the layer. The materials are arranged in the two layers with the first material at the bottom of a vessel and with the second material disposed above the first material. An elongate withdrawal conduit projects into the vessel to define (1) an exit port at the wall of the vessel, (2) a confined flow passageway communicating with the exit port within the vessel, and (3) at least one withdrawal aperture with the uppermost portion of any withdrawal aperture being lower than the uppermost portion of the exit port. The upper surface of the first material layer is maintained below the conduit while flow of the second material from the second material layer is effected into and through the conduit via the withdrawal aperture.

Abstract: A method of regenerating strong-base anion exchange resins which have been used in the extraction of complex anions followed by elution with a thiocyanate strip solution is provided. The method involves the use of ferric ions in a regenerating solution together with a substitute anion for attachment of the resin, the regeneration taking place under conditions in which ferric-thiocyanate complex cations are formed and washed from the resin by the regenerating solution. The thiocyanate can be recovered by neutralizing the regenerating solution to precipitate ferric hydroxide and leave thiocyanate in solution.

Abstract: Salt composition and method for regenerating spent water softener cation exchange resins, to remove or prevent the accumulation of iron in its various forms, insolubles, and oily deposits. The dry composition comprises from about 10 ppm to about 400 ppm of an alkylated diphenyl oxide disulfonate surfactant, from about 500 ppm to about 8000 ppm of sodium citrate, and as the remainder of the composition sodium chloride. The composition is preferably provided and used in the form of compacted products. The method for regenerating the spent cation exchange resin bed comprises the step of contacting the resin bed with an aqueous brine solution containing from about 25 to about 1200 ppm sodium citrate and from about 0.5 to about 60 ppm of alkylated diphenyl oxide disulfonate surfactant. The method is conveniently practiced by dissolving the composition first set forth above in the water of a conventional brine tank, using known technology.

Abstract: A method for regenerating a perfluorinated cation exchange polymer membrane which can give only a low current efficiency as a result of being used as a diaphragm in an electrolytic cell or an electrodialyzer, said method comprising maintaining said perfluorinated cation exchange polymer membrane at a temperature of at least 110.degree. C. while keeping it in contact with an aqueous solution of a strong acid having a pH at ordinary temperature of not more than 1.0.

Abstract: A powdery cation-exchange resin and a powdery anion-exchange resin which are coupled to each other are stripped apart by the use of an electrolytic solution whose ionic strength is 5 to 15, and both the stripped ion-exchange resins are separated by letting them stand or by employing a centrifugal separator, thereby regenerating the powdery cation-exchange and anion-exchange resins.

Abstract: The invention relates to a process for internal regeneration of mixed bed filters in which, after the exhausted ion exchanger mass has been separated into the two components and these have been regenerated and washed out, the exchanger layer in the region of the cation exchanger/anion exchanger interface is selectively removed from the mixed bed filter, the cation exchanger remaining in the filter is mixed with the anion exchanger remaining in the filter for the new loading stage, the ion exchanger mass removed from the filter is added again, when the work cycle has ended, to the exhausted ion exchanger mass before or during the separation into cation exchanger and anion exchanger, and, after the separation, the loading stage is started again with the regeneration of the cation exchanger and anion exchanger; and also to a mixed bed filter for carrying out the process.

Abstract: A method for cleansing organically fouled anionic exchange resins is disclosed wherein, in addition to cleansing with caustic and/or brine, the fouled resin is contacted with an effective diethylene glycol compound or derivative thereof.

Abstract: A process for regenerating the anion and cation exchange resins used for polishing water for steam generation allows the polishers to be operated with reduced effluent levels of sodium, chloride and sulfate to prevent corrosion of the steam turbine power plant system. In the process, both the cation and anion exchange resins are treated only with neutral or alkaline aqueous solutions including ammonium sulfate.

Abstract: Methods for cleaning organically fouled anion exchange resins are disclosed. In addition to cleaning with brine and/or caustic, the fouled resins are contacted with an aqueous solution comprising an effective cleaning agent having the formula R--O--H wherein R is alkyl (C.sub.1 -C.sub.4) or hydroxylated alkyl (C.sub.1 -C.sub.4). Isopropanol is preferred.

Abstract: This invention relates to the regeneration of cation exchanger resin containing adsorbed magnesium ions, and the recovery of the magnesium as a crystalline precipitate. The regeneration uses moderate to high concentration aqueous H.sub.2 SO.sub.4, and the recovered precipitate comprises one or more co-crystallization compounds of MgSO.sub.4 and H.sub.2 SO.sub.4.

Abstract: A mixed bed polishing process for regeneration of an exhausted mixed resin bed of cation exchange and anion exchange resins of different densities comprising the steps of scrubbing with air the exhausted mixed resin bed and adding into the mixed resin bed inert resins having a density intermediate the densities of the cation exchange and anion exchange resins. The exhausted mixed resin bed is backwashed to separate into three layers the cation exchange, anion exchange and inert resins. The anion exchange resins are transferred to an anion regenerator; and then, the inert resins are transferred to an inert resin storage tank. The cation exchange resins are regenerated with acid; and then, the anion exchange resins are regenerated with caustic regenerant. The regenerated cation exchange and regenerated anion exchange resins are separately rinsed, and then, mixed together and rinsed.

Abstract: A process for the direct regeneration of acid resin using a nonaqueous eluant saturated with anhydrous acid.

Abstract: In a method of regenerating mixed ion exchange materials, the materials are classified into layers. The lower layer is then transferred from the separator vessel. The transfer is controlled by detecting an interface between materials. The separated materials are then regenerated after which the anion material is reclassified to allow any contaminant cation material to settle to the bottom thereof. Material is then removed from the bottom of the anion layer to remove settled contaminant cation material. The removed material is isolated from the regenerated materials which are then remixed.The method reduces the cross-contamination of materials that occurs during the separation of classified materials and, particularly, reduces the amount of cation material in the sodium form (following regeneration of the anion material) that is eventually returned to service.

Abstract: A method of regenerating particles in an ion exchange column wherein the physical characteristics of a regenerating fluid cause regenerated particles to be displaced from the original bed of particles and flow in a direction countercurrent to that of the fluid.

Abstract: This invention relates to a process for regenerating a strongly acidic cation exchange resin which has used for a desalting treatment or partition chromatographic separation of a sugar liquid which lowers its separation capability, by means of contacting said strongly acidic cation exchange resin with an enzyme solution.

Abstract: A method for regenerating the exhausted anion and cation exchange resins in a mixed bed demineralizer which utilizes an inert material of a specific density intermediate to the specific densities of the anion and cation resins. The inert resin remains in the regeneration system and is not returned to the service vessel with the regenerated resin.

Abstract: An automated plant for the regeneration of exhausted cation exchange material and exhausted anion exchange material involves the use of novel pretreatment and separation procedures, the use of novel regeneration processes, neutralization of waste chemicals and the use of novel cylinder recharging procedures. Electronic process controls are used to effect automatic operation.

Abstract: In mixed bed ion exchange resin regeneration processes, transfer of resin after classification is controlled by detecting a change in a parameter of transfer water dependent on ion concentration, e.g. conductivity. The process includes increasing the ion concentration of the transfer water. The increased ion concentration ensures that large percentage uncontrolled fluctuations in the conductivity of the water do not mask the change required to be detected. The ion concentration can be increased by adding, for example, decationized water to the transfer water.

Abstract: A stratified bed of ion exchange resins is regenerated by countercurrent or upflow regeneration. Expansion of the bed is prevented by returning used regenerant solution to the top of the bed and pumping the returned regenerant solution downwardly through the layer of resin at the top of the bed. Recycling of the used regenerant solution also regenerates the upper layer of resin.

Abstract: A process for the demineralization of a bicarbonate- or bisulphite-bearing saline solution by means of amphoteric thermally regenerable ion-exchange resins and comprising the regeneration of the resins using as a regenerating agent a solution which is more acidic by a chosen amount than is the saline solution.

Abstract: A method for simple and very precise regeneration of ion exchanger resins with solutions of chelating agents, such as ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diaminocyclohexanetetraacetate (DcyTE), or diethylenetriaminepentaacetate (DTPE). The method includes utilization of chelating agents as well as their salts.

Abstract: Adsorbed calcium is selectively removed from cation exchange resins in the presence of adsorbed magnesium by eluting the resin with aqueous sulfuric acid saturated with CaSO.sub.4 and undersaturated with MgSO.sub.4 to obtain a solution supersaturated with CaSO.sub.4 from which the CaSO.sub.4 can be readily precipitated. The magnesium is subsequently removed from the resin by eluting with aqueous sulfuric acid, such as 20-70% H.sub.2 SO.sub.4. The method is advantageously used in the regeneration of cation exchange resins, such as the loaded resins used for treatment of phosphate rock-derived phosphoric acid.

Abstract: A process is disclosed for the regeneration of a sorbent, particularly an ion exchanger used in the recovery, isolation or production of sugars, wherein a regeneration solution is used which contains at least 20 meq/l of an alkali metal hydroxide or hydroxide of an alkaline earth metal having an atomic number of at least 20, and at least 1% by weight of a monosaccharide or disaccharide.

Abstract: Chromate ions present in aqueous solutions, e.g. cooling tower blowdown water or liquors obtained from the electrolysis of aqueous sodium chloride solutions, are substantially completely removed by passing the solution through an intimate mixture of an anion exchange resin in the chloride form and a weak cation exchange resin in a conditioned hydrogen form.

Abstract: A mixed bed deionizer unit which provides in situ regeneration through the use of two compact multi-valve assemblies and an intermediate manifold which are automatically controlled to supply backwash water, chemical draw for cleansing both cation and anion resins simultaneously and rinsing water in a sequentially controlled manner. An internal water and chemical distribution system in the mixed bed tank is provided which has both input distribution and output drainage capabilities.

Abstract: Ion exchangers in which both cation and anion exchange groups are present may be regenerated by treating the ion exchanger with a regenerant for one type of ion exchange group, either anion or cation, and subsequently treating the ion exchanger with an ion exchange emulsion bearing the desired ions to regenerate the other type of ion exchange group.

Abstract: Flocs prepared by mixing cationic and anionic emulsion ion exchange resins are useful as a filtration and deionization medium. Flocs prepared from weakly acidic and weakly basic emulsion ion exchange resins may be regenerated thermally.

Abstract: An ion exchange resin bed capable of hydraulic segregation into discrete zones of ion exchange resins having different ion exchange functionalities, the resins being produced by functionalizing fractions of a single batch or lot of precursor copolymer which have been segregated on the basis of differing hydraulic densities of the different sized particles, and the method for producing the same.

Abstract: Charged anion exchange resins, which are used for the removal of strong acid ions from water, are regenerated to their bicarbonate form by contacting them with an aqueous treating medium containing calcium carbonate and carbon dioxide.

Abstract: A high degree of water purity is obtained from a mixed-bed deionization process by minimization of cross-contamination of the cation and anion materials. After service, the materials are classified into superimposed uppermost, intermediate and lowermost layers above a perforate barrier in a separator vessel. The vessel has an elongate conduit having an inlet adjacent the barrier and an outlet outside the vessel. At least a major proportion of the material of the lowermost layer is passed through the outlet of the conduit and an interface between materials is detected. Thereupon, the conduit outlet is isolated from the conduit inlet so as to segregate in the conduit material from the intermediate layer. The ion exchange materials are then regenerated and re-mixed. The segregated material is independently removed from the conduit before the next regeneration cycle starts.

Abstract: This invention relates to removal of cerium, used as a free-radical initiator, from aqueous polymeric dispersions, particularly starch graft copolymer dispersions, by adsorbing cerium (III) onto a strong cation exchange resin, to separation of the adsorbed cerium (III) from the resin using a solution such as sodium sulfate or sodium oxalate to form a cerium (III) precipitate, and to oxidation of the separated cerium (III) to cerium (IV).

Abstract: Normally solid copolymers of a fluorinated vinyl monomer and a perfluorinated vinyl compound having a carboxyl and/or sulfonyl group attached directly to the perfluorinated vinyl group or indirectly through an alkyl or ether linkage have been found to be soluble in low molecular weight polymers of perhalogenated alkyl ethers, low molecular weight polymers of perhalogenated alkyls and perfluoro kerosenes, each of said solvent materials having boiling points between about 200.degree. C. and 350.degree. C. The copolymeric material dissolved in accordance with the instant invention can readily be resolidified by solvent removal and hydrolyzed or converted to the salt form to become a cation exchange material having an equivalent weight in the range of 1000 to 1600.When these cation exchange materials in the salt form become damaged or contaminated during operation, for example in an electrochemical cell, they may now be reclaimed rather than discarded.

Abstract: A method for regenerating a weak base anion exchanger which comprises passing a regenerating chemical in an upward direction through a granular resinous mass of an exchanger, thereupon displacing the chemical and rinsing the mass with water. The regenerating chemical is a lime slurry having a concentration of 1 to 5% by weight, which is both supplied to and withdrawn from the granular mass in an evenly distributed flow with a flow rate of at least 10 m.sup.3, per hour, per m.sup.3 resin material (m.sup.3 /h/m.sup.3), while the granular mass is in a compacted state.

Abstract: Cation exchange water softeners may be regenerated and, then, the regenerant wastes (brine) recovered, treated, and recycled. The result is a closed system which is ecologically beneficial. The regenerant brine is captured in as concentrated a form as possible and then treated with a precipitant such as sodium or potassium carbonate or mixtures of sodium or potassium carbonate with sodium or potassium hydroxide. Calcium and magnesium compounds are precipitated and the supernatant contains sodium or potassium chloride. These are separated within the brine treatment tank, the precipitate being disposed of as a sludge or sludge cake and the supernatant being recycled to the water softener at the time of further regeneration.

Abstract: A process for demineralizing an aqueous saline solution containing a deoxygenating agent by treating it with a thermally regenerable ion-exchange resin comprising a resinous material derived from a substituted diallylamine.

Abstract: An ion exchange process for desalination wherein a thermally regenerable ion exchange resin having weakly acidic free acid groups and weakly basic free base groups is carbonated, for example by contact with an H.sub.2 CO.sub.3 solution, whereby the free base groups are converted to a carbonate form. The conversion may be effected either prior to or simultaneously with contact between the resin and the solution to be desalinated. Both fixed bed and continuous or semi-continuous resin systems are usable. The process maintains the desalination capacity at a high level while providing effective desalination.

Abstract: Ions are exchanged between emulsion ion exchange resins and conventional ion exchange resins during both batch and column contact. This process may be used to place the emulsion resin or the conventional resin in the desired ionic form.

Abstract: A process is disclosed in which a spent mixed anion/cation exchange resin bed is hydraulically separated into cation, anion and interface resin cuts. The interface resin cut is further classified by various physical separation techniques. Cation and anion resins are separately chemically regenerated. In an alternative embodiment cation resin fines are physically separated from the anion resin cut.

Abstract: A method of rinsing a wetted particulate solid bed in liquid-contacting service by gravity draining or by gas blowing the bed and then rinsing it with successive gas-impelled pulses of rinse liquid.

Abstract: There is provided an improvement in the method of regenerating the anion portion of a mixed anion/cation exchange resin bed used for purification of condensate water. The improvement comprises utilizing a clear dilute lime solution substantially free of non-hydroxylic anions. This solution is produced by passing a solution of calcium salt through a strong base anion exchanger in the hydroxyl form, and thus producing calcium hydroxide by salt splitting. The spent resin is regenerated with spent caustic regenerant from a condensate purification process or with fresh caustic. It is preferred that the calcium solution and the regenerant enter the ion exchanger in counterflow pattern to minimize leakage of non-hydroxy ions.

Abstract: After weak base ion exchange resins are regenerated and washed with water, the resins are contacted with a solution of carbonic acid to remove the remaining regenerant wastes.

Abstract: Foulants are removed from ion exchange resins by treating the foulant coa ion exchange resin with a weak aqueous solution of a compound that quickly decomposes the foulants.

Abstract: Waste waters, particularly waste waters with radioactive contamination, are cleaned by a sorption-precipitating process, where the sorbent retaining cations are regenerated that is, activated, by a solution, the cationic component of which forms with anionic contaminations a precipitate, taking along cationic contaminations, and simultaneously sticking on the surface and within pores of the sorbent.

Abstract: Process for conditioning contaminated ion-exchange resins, more particularly contaminated cationic resins, wherein the contaminated ion-exhange resin or resins are brought into contact with a basic compound in a sufficient quantity to block the active sites of the cationic resin or resins, the thus treated ion-exchange resin or resins are incorporated into an ambient temperature-thermosetting resin and the latter is crosslinked.

Abstract: Loaded solid resin particles obtained as an output slurry from a continuous fluid/solid contactor are stripped by counter-current elution in which discrete measured batches of the loaded resin are isolated, each batch is drained of its carrier liquid, and successive drained batches are then slurried intermittently into the bottom of an elution column using strong eluate from the elution column to slurry the resin into the bottom of the column.