Abstract: A method for determining the amount of residual disinfectant removing agent in a process stream to which the disinfectant removing agent has been added to completely remove a disinfectant residual, comprising the steps of: (a) drawing off a sample of the process stream; (b) mixing an acidic iodate solution and an iodide solution to produce an iodine analyzing agent; (c) adding to the sample the iodine analyzing agent in an amount sufficient to react with the residual disinfectant removing agent and leave an unreacted amount of residual iodine; (d) allowing sufficient time for the iodine to react with the residual disinfectant removing agent; (e) analyzing the sample to determine the amount of residual iodine remaining in the sample, and (f) determining the amount of residual disinfectant removing agent in the sample based on the amount of iodine analyzing agent added and the amount of residual iodine remaining in the sample after reaction.

Abstract: A method of purifying water includes contacting water containing an oxide of chlorine, such as chlorine dioxide, chlorite, or chlorate, with a water purification composition that includes a Group 11 or Group 12 metal such as silver, copper, or zinc.

Abstract: A bottled fluoridated water based drinking composition for the prevention and control of dental decay includes in a substantially non-fluoride reactive bottle containing therein at least one additional fluoride compound selected from a group consisting essentially sodium fluoride, potassium fluoride, magnesium fluoride, calcium fluoride, stannous fluoride, sodium monofluorophosphate, potassium monofluorophosphate and hydrogen fluoride and physiologically acceptable salts thereof, an acidifying compound which when dissolved in water will provide a weak acid and a weak base to initiate a buffering action and prevent the fluoride ions from going to completion and other selected formulating agents to provide protection of tooth surfaces from tooth caries disease and eventual tooth loss.

Abstract: The invention describes a process for controlling contamination of oil production system waters by sessile bacteria, comprisinga) addition of a slug dose of a biologically effective amount of a quick-kill biocide, simultaneously with or followed byb) intermittent addition of a biologically effective amount of a control biocide.This dosing regime is found to be surprisingly effective when compared with known dosing regimes.

Abstract: A composition and a process for substantially reducing or removing sulfide from a sulfide-containing fluid are disclosed. The composition comprises, or is prepared by combining components comprising, a sulfide-containing fluid and a sulfide-scavenging amount of a sulfide scavenger selected from the group consisting of bromates, iodates, and combinations of two or more thereof. The process comprises contacting a sulfide-containing fluid with a sulfide-scavenging amount of a sulfide scavenger under a condition sufficient to substantially reduce the sulfide concentration in the fluid.

Abstract: A process for disinfecting protein solutions operates by flowing the solutions through a bed of iodinated organic polymer that acts as a gel filtration material. The preferred types of gel filtration material is Sephadex brand cross-linked dextrans, either G-25 or A-25 (DEAE modified Sephadex). The various types of cross-linked dextrans are readily iodinated before use by being mixed dry with elemental iodine at an elevated temperature such as 37.degree. C. Sephadex brand cross-linked dextrans can be readily iodinated to 50% weight of iodine to weight of dextrans or more. The preferred level of iodination is 30-40%. Before use the used it is first swelled in aqueous medium and then poured into a chromatographic column. Six ml of swelled 30% iodine Sephadex A-25 can effectively destroy virus in at least one liter of 5% human IgG.

Abstract: A water treatment system and apparatus for producing bacteria- and virus-free water from a bacteria and virus-containing water supply, said apparatus comprising(a) generator means for holding solid elemental iodine and to allow solubilization of said iodine under dynamic aqueous flow;(b) means for feeding a first portion of said water supply to said generator means to produce an aqueous concentrated iodine solution;(c) means for providing a second portion of said water supply;(d) means for providing said aqueous concentrated iodine solution to said second portion of said water supply to provide a blended water supply;(e) storage means for holding said blended water supply to provide said bacteria- and virus-free water;(f) means for measuring water flow of said first and said second portions;(g) means for measuring the pH of said second portion;(h) means for adjusting the pH of said second portion;(i) means for measuring the temperature of said concentrated aqueous solution; and(j) control means for receiving

Abstract: Effective, multi-use filter cleaning compositions include 5% to 60% of a strong acid, 1% to 40% of a surfactant, and 0.5% to 20% of a sequesterant/builder. The filter cleaning compositions optionally include 0.5% to 10% of a water soluble organic solvent, and/or 0.5% to 10% of a nonionic surfactant.

Abstract: Solid and liquid substrates, such as soil and solvents having radioactive metals or hazardous non-radioactive metals are decontaminated with the aid of cyanide ion generated in-situ to form co-ordination compounds with the unwanted metal contaminants. Cyanides are prepared by introducing into an ammoniacal liquid-containing slurry of a contaminated soil, or other solid or liquid substrate, a refrigerant compound, such as a hydrochlorofluorocarbon which produces ammonium cyanide, which in-turn forms a complex with the hazardous metal contaminant for separation with the ammoniacal liquid. The process may also utilize solvated electrons to at least partially dehalogenate a perhalogenated refrigerant like diclorodifluoromethane (R-12). Process avoids exposure to potentially hazardous cyanides through in-situ generation, while simultaneously destroying unwanted refrigerants which are potentially harmful to Earth's ozone layer.

Abstract: A novel method and compositions are disclosed for the treatment of water in recirculating water systems. The method includes providing a boron level of at least 20 ppm in the water, continually eroding into the water a compressed sanitizer/algicide component including a halogen source material, a boron source material, and glycoluril, and periodically adding to the water an oxidizing clarifier comprising a chlorine source material, a non-halogen, chlorine source material, and a boron source material. The invention also provides novel water treatment chemicals including the compressed sanitizer/algicide component and the clarifier useful in the foregoing system. The system and compositions are safe and reliable, control algal and fungal growth and generally provide improved water quality for recirculating water systems.

Abstract: Disclosed is a process for disinfecting water which provides a visual indication after the disinfection is complete. First, the water to be disinfected is generally simultaneously intermixed with at least three items. The items are: (1) a disinfectant which is adapted to render harmless substantially all pathogens present in the water upon the disinfectant being intermixed with the water for a time period T.sub.k ; (2) a colorant; and (3) a material which can remove substantially all of the disinfectant and colorant from the water over a time period T.sub.r, where T.sub.r is greater than T.sub.k. Secondly, the water, disinfectant, colorant and the removing material are allowed to remain intermixed for a time period of T.sub.r or greater. At the end of the time period T.sub.r, substantially all pathogens in the water will be rendered harmless, substantially all of the disinfectant will be removed from the water and substantially all of the colorant will be removed from the water.

Abstract: A slow-dissolving sanitizing and clarifying puck for use in water such as swimming pool water preferably includes about 63% to about 80% trichloro-s-triazinetrione, about 4% to about 12% sodium tetraborate, about 10% to about 22% aluminum sulfate, and about 1% to 5% glycoluril.

Abstract: A water purification through-flow device which comprises a cylindrical shell which is divided lengthwise into two or more sectors, separated from each other by partitions, with a cover fitting one end of the shell, in which cover there is provided an inlet for water which is to be purified. Depending on the number of sectors, the outlet is provided in the same cover if there are two sectors, and in the other cover if there are three sectors: the water flowing through each of the sectors one after the other. The individual sectors may contain the same purification substance, or different sectors can contain different ones. There may be provided mechanical filtration means for the water passing through the device, and there may be provided means for closing the various sectors during storage.

Abstract: A filter for disinfecting non-potable water is disposed in-line in a water delivery pipe, such filter having a plurality of chambers. The first chamber contains biocidal resin which imparts a biocide residue to the water as it passes there-through to kill microorganisms. The water then passes through a turbulating disk to an extended contact time chamber of a selected volume to allow further contact time between the biocide residue and any microorganisms in the water. The water then passes through a 1-3 micron screen, which acts to retain protozoan cysts within the filter, and then passes through a biocide removal chamber containing medias which remove the biocide from the water. The water then passes through a chamber containing bacteriostatic media which acts to prevent back contamination from the effluent end of the filter.

Abstract: A water treatment system including a tank for containing a solid treatment product such as a solid halogen. The water treatment system is adapted to be used in combination with a cooling system wherein treated water is fed to the cooling system through an outlet conduit leading from the tank. Drainage of water from the tank is facilitated by use of an eductor connected to an inlet conduit for the tank whereby water is drained from the tank to the inlet conduit and back to the outlet conduit, and is thereafter conveyed back to the cooling system. Thus, a closed system is formed by the treatment system in combination with an associated cooling system wherein the closed system is substantially environmentally safe in that drainage of the tank outside of the closed system is avoided.

Abstract: A personal portable water purifying and drinking device. The device includes a conduit having a chemical purification stage positioned at one end of the conduit, and a filtration stage positioned at the opposite end of the conduit. The chemical purification stage includes a chemical purifying agent and a residence chamber to neutralize bacteria and viruses. The filtration stage includes a filter and a cleaning medium, the filter having a diameter larger than the diameter of the conduit, and designed to remove exceedingly small microorganisms, such as potentially harmful parasites 1-2 .mu.m in size, from the water to be filtered. A mouthpiece is mounted after the filtration stage of the conduit to draw fluid through the device and into the user's mouth.

Abstract: A novel method and compositions are disclosed for the treatment of water in recirculating water systems. The method includes providing a boron level of at least 20 ppm in the water, continually eroding into the water a compressed sanitizer/algicide component including a halogen source material, a boron source material, and glycoluril, and periodically adding to the water an oxidizing clarifier comprising a chlorine source material, a non-halogen, chlorine source material, and a boron source material. The invention also provides novel water treatment chemicals including the compressed sanitizer/algicide component and the clarifier useful in the foregoing system. The system and compositions are safe and reliable, control algal and fungal growth and generally provide improved water quality for recirculating water systems.

Abstract: The present invention comprises an improved method and apparatus for treating water in heat exchange systems. The present invention automatically and inexpensively provides an effective chemical to process water systems at times and in proportion to the need for water treatment in such systems. When used in evaporative cooling systems, the present invention adds the treatment chemical to the system via the make-up water. The make-up water acquires a substantially constant concentration of treatment chemical as it is passed through a device containing a treatment chemical. The constant concentration of chemical is achieved by dividing the make-up flow into two streams within the device, saturating the smaller of the two streams with chemical, and re-mixing the two streams. The biocide agent used in the preferred embodiment of the invention is prilled elemental iodine.

Abstract: A novel method and compositions are disclosed for the treatment of water in recirculating water systems. The method includes providing a boron level of at least 20 ppm in the water, continually eroding into the water a compressed sanitizer/algicide component including a halogen source material, a boron source material, and glycoluril, and periodically adding to the water an oxidizing clarifier comprising a chlorine source material, a non-halogen, chlorine source material, and a boron source material. The invention also provides novel water treatment chemicals including the compressed sanitizer/algicide component and the clarifier useful in the foregoing system. The system and compositions are safe and reliable, control algal and fungal growth and generally provide improved water quality for recirculating water systems.

Abstract: A method for purifying an etching solution consisting of an aqueous phosphoric acid solution which has been used in etching of a silicon nitride film. In the process, hydrogen fluoride is added to an etching solution consisting of an aqueous phosphoric acid solution which has been used for etching of a silicon nitride film, and the resulting solution is heated to remove fluorides of silicon as reaction products of hydrogen fluoride with silicon compounds which have been contained in the etching solution together with vaporized water.

Abstract: The invention relates to a process and means for the oxidative destruction of azides. The process is characterized in that the azide-containing solutions to be disposed of are treated with an iodine solution in the presence of an iodide and a thiosulfate. The means are preferably employed in the form of tablets.

Abstract: Microemulsions of water-insoluble active ingredients, employing a special surfactant system and solvent system. These microemulsions remain thermodynamically stable over a wide range of water dilutions.

Abstract: An automatic system to precisely maintain bactericidal action in a reservoir of water equipped with a recirculation system, such as a swimming pool, decorative fountain, spa, cooling water reservoir or the like. The automatic system includes: a service loop which bypasses a portion of the recirculating water past sensors which measure the pH and oxygen reduction potential (ORP) of the water and in which acid and halogen are injected by a chemical feed unit; an electronics unit for determining the injection quantity of the acid and/or halogen needed to restore pH and ORP to stored set-points, and for controlling the chemical feed unit in response to the injection time determination; and an optional telecommunication unit for reporting process control status to a remote location and allowing modification of the process parameters, selection of operating modes, and performance of diagnostic tests from the remote location.

Abstract: The present invention comprises an improved method and apparatus for treating water in heat exchange systems. The present invention automatically and inexpensively provides an effective chemical to process water systems at times and in proportion to the need for water treatment in such systems. When used in evaporative cooling systems, the present invention adds the treatment chemical to the system via the make-up water. The make-up water acquires a substantially constant concentration of treatment chemical as it is passed through a device containing a treatment chemical. The constant concentration of chemical is achieved by dividing the make-up flow into two streams within the device, saturating the smaller of the two streams with chemical, and re-mixing the two streams. The biocide agent used in the preferred embodiment of the invention is prilled elemental iodine.

Abstract: A process for oxidizing a compound comprises contacting the compound with iodide ions and irradiating the iodide ions with UV light of a wavelength sufficient to generate iodine atoms. The compound is then oxidized with the resulting iodine atoms. The iodine atoms are reduce to iodide ions as a result of the oxidation of the compound.

Abstract: A process for the removal of mercury from industrial waste streams is disclosed wherein the waste stream is a nitrate based solution that has been decomposed by the addition of hypochlorite. The method involves adding a reducing agent to reduce the hypochlorite and/or adjusting the pH by the use of a strong acid to less than about 2.0, converting any residual chlorine to a soluble unreactive salt, adding a soluble precipitating agent, such as sodium sulfide, to the solution in a ratio to the mercury present of greater than 1:1 to about 2:1 to precipitate out the mercury as a mercury compound. The solution is then filtered to remove the precipitated mercury compound.

Abstract: A process for treating an aqueous waste water or groundwater containing organic contaminants degradable by hydrated electrons comprises contacting the aqueous waste water or groundwater with an agent which generates hydrated electrons on photolysis. Additionally, the aqueous waste water or groundwater is irradiated with UV light to photolyse the hydrated electron generating agent, thereby generating hydrated electrons to degrade the contaminants. In one embodiment, the aqueous waste water or groundwater is contacted with the hydrated electron generating agent and a reducing agent to recycle the hydrated electron generating agent.

Abstract: Silicone dosage forms adapted for the continuous and controlled release of iodine values, notably to domestic water supplies for the treatment of the various disease states attributed to iodine deficiency, are heat-shaped from (A) a thermoplastic silicone copolymer, and (B) a therapeutically effective amount of at least one water soluble, nontoxic, organic and/or inorganic iodine compound which is in solid state at ambient temperature.

Abstract: A toilet cleaning block which releases a halogen disinfecting agent in a controlled, substantially constant rate for 2 to about 4 months of constant contact with water and is then completely dissolved in the water comprises an admixture of an agent which releases a halogen disinfecting agent when in contact with water, about 4 to 10% aluminum hydroxide based on the total weight of the block and up to about 1% by weight of a mold release lubricant, said admixture being in the form of a coherent solid resistant to internal water penetration having a density of 1.10 to 1.60 g/cc, a ratio of effective surface area to weight of about 1:1.05 to 1:1.25 and a crush fracturing strength of about 9-109 kg.

Abstract: A method and apparatus are disclosed for maintaining continuous, long-term microbial control in the water supply for potable, hygiene, and experimental water for space activities, i.e., space shuttle, orbiter lab, Lunar base, Mars base, deep space missions, etc., as well as treatment of water supplies on earth. The water purification is accomplished by introduction of molecular iodine into the water supply to impart a desired iodine residual. The water is passed through an iodinated anion exchange resin bed. The iodine is bound as I.sup.-.sub.n at the anion exchange sites and releases I.sub.2 into the water stream flowing through the bed. Suitable anion exchange resins are Amberlite IRA 401S (Rohm & Haas); Dowex SBR (Dow Chemical); and Ionac ASB-1P (Sybron Corp.). The concentration of I.sub.2 in the flowing water gradually decreases and the ion-exchange bed has had to be replaced.

Abstract: The present invention relates to a method of reducing the content of halogenated organic compounds in the spent bleach liquor from the bleaching of lignocellulose-containing material with compounds containing halogen, wherein the spent bleach liquor, in a stage where no essential delignification or bleaching of the pulp takes place, is maintained at a pH of from 2.5 up to about 10, and wherein the residence time and the temperature are selected such that the amount of dissolved halogenated organic substances in the spent bleach liquor is reduced by at least 30%.

Abstract: A process for inhibiting the adhesion of bacterial cells to solid surfaces in aqueous systems and thus controlling biological fouling comprising adding a water-soluble ionene polymer to the aqueous systems in an amount ranging from about 0.5 ppm to about 50 ppm based on the weight of aqueous liquid in the system.

Abstract: Polymeric quaternary ammonium trihalides, preferably triiodides, and use of polymeric quaternary ammonium trihalides to inhibit the growth of microorganisms in aquatic systems, to disinfect or sanitize surfaces and to disinfect the skin of animals, including humans.

Abstract: Monofluorophosphate salts, especially sodium monofluorophosphate (Na.sub.2 PO.sub.3 F), when added to potable water sources in concentrations between 0.1 mg/L and 500 mg/L, significantly reduces lead (Pb) leaching into said water, producing the double benefit of reducing lead solubility and thus content in drinking water, while at the same time adding fluoride to that drinking water, with the anticaries benefit that fluoridation provides.

Abstract: The ability of a waste treatment process to remove selenium from a waste stream is improved by pretreating the waste with a compound selected from the group having the formulaX(ZO.sub.a).sub.b,Q.sub.m O.sub.n,ClO.sub.3,Cl.sub.2 O.sub.6,Br.sub.3 O.sub.8,I.sub.2 O.sub.5, andmixtures thereof, wherein X is a cation, Z is halogen selected from the group consisting of chlorine, bromine, and iodine, a is an integer from 1-3, b is an integer equal to the valence of X, Q is chlorine or bromine, and m and n are each 1 or 2, provided than m+n equals 3.

Abstract: Fountain permitting the release of active agents into water originating from a well, comprising a passage for circulating the water drawn from the well around a cartridge containing the active agent to be diffused and for keeping this cartridge immersed in water when water is not being drawn from the well.

Abstract: A process for decomposing a solution of a hydroxylammonium compound includes raising the pH of the solution to about 8 or higher and reacting the alkaline solution with a source of hypohalite ions. The process decomposes solutions of hydroxylammonium salts in a manner which produces benign liquid and gas effluents which can be readily disposed of or discharged.

Abstract: A process is provided for controlling the emission of nitrogen dioxide from, and the growth of living organisms in, steam condensate cooling towers and catch basins used in conjunction with steam and condensate of steam derived from ammonia and geothermal brine containing dissolved iron. The process comprises contacting the condensate, in a substantially continuous manner, with a small, substantially less-than-stoichiometric amount of an oxidizing biocide, such as trichloroisocyanuric acid or 1-bromo-3-chloro-5,5-dimethyl-hydantoin, which results in the oxidation of said nitrite formed by activity of bacterial in the condensate to a non-reactive nitrate, and which slows the growth of said bacteria in the cooling tower and catch basin. The process additionally includes periodically introducing into the condensate with amounts of a second biocide, such as dodecylguanidine hydrochloride or isothiazalone, which provides most of the control or organism growth in the cooling tower and catch basin.

Abstract: A process for abating the emission of hydrogen sulfide from a condensate of steam, derived from a sulfide-containing geothermal brine, comprising introducing an oxidizing agent into the condensate in an amount less than that which would be required to directly oxidize all the sulfide to sulfate. The process optionally provides for periodically introducing a biocide into the condensate to control the growth of organism therein.

Abstract: A method for treating a solid surface exposable to protein solutes is provided that reduces interactions of the protein solutes with the surface. Thus, a small bore capillary tube, useful for electrophoretic separation, comprises a reduced interaction phase coated along the bore that includes a terminal moiety covalently bound in the reduced interaction phase through at least one heteroatom. This terminal moiety includes a plurality of halogen atoms, and preferably is an aryl pentafluoro.

Abstract: An apparatus for quantitative determination of trihalomethanes comprises a separation unit containing two channels in contact with each other via a microporous membrane that will not react with trihalomethanes, a reaction unit for heating a carrier solution that has passed through the separation unit, a cooling unit for cooling the carrier solution that has undergone complete reaction; and a detection unit for determining the quantity of a fluorescent substance in the carrier solution. A method for quantitative determination of trihalomethanes comprises flowing a sample solution or a mixture thereof with a reducing agent through one of the two channels in the separation unit, flowing the carrier solution through the other channel, heating the carrier solution that has passed through the separation unit and to which an alkaline nicotinamide or a derivative thereof has been added, cooling the carrier solution, and subjecting the cooled solution to fluorimetry.

Abstract: A method of inhibiting the corrosion of the metal surfaces of beer pasteurizing units in contact with halogenated water vapor which comprise treating these halogenated waters with at least 1/4 ppm sulfamic acid for each ppm of halogen present in these waters.

Abstract: A method of geologically confining toxic industrial waste, the method consisting of: using a cavity (1) previously leached from a mass of rock salt (2), the cavity being initially filled with brine (5); incorporating the waste in a pumpable waste-containing mixture (10) of density greater than the density of the brine and suitable for setting once put into place; inserting a predetermined quantity of a buffer liquid (7) into the bottom of the cavity by means of a dip tube (8) positioned in a well (4) and in communication with the surface (3), the buffer liquid being immiscible both with the brine and with the waste-containing mixture, the density of the buffer liquid lying between the density of the brine and the density of the waste-containing mixture, and the buffer liquid including one or more halogen-containing solvents; inserting the waste-containing mixture into the cavity by the means of the dip tube while the bottom end of the dip tube is maintained within the previously inserted buffer liquid; and re

Abstract: A means for promoting the neutralization reaction between particulate calcium carbonate and ionized phosphate by adding a material formed by the reaction of particulate calcium carbonate and dilute hydrofluoric acid. The products of this invention are useful in lowering serum phosphate levels in patients undergoing renal dialysis, and are also useful as antacids. These products are also useful in the treatment of water and waste water to lower phosphate content.

Abstract: A process and apparatus employing nylon 4 for the purification of water comprising the steps of contacting the water with iodine in a first treatment zone; nylon 4 complexed with iodine rather than elemental iodine is preferably used and is contacted by the water in the first treatment zone where it releases iodine at levels sufficient to purify the water. The treated and purified water is then contacted with nylon 4 in a second treatment zone where the iodine is removed from the water. The apparatus comprises a conduit having an inlet and an outlet, with a first treatment zone containing nylon 4 material complexed with iodine and a second downstream treatment zone containing nylon 4. The nylon 4 material used in both treatment zones can be in any form, preferably a form having a high surface area. A suitably restrained moistened fine powder may be used as may be textured or untextured, drawn or undrawn, staple fiber, knitted or non-woven fabrics or pulp (fibrils).

Abstract: An agent is disclosed that is useful for treating liquid media, e.g., dechlorinating aqueous media. The agent contains at least one salt from the sulfur oxide family, such as sodium sulfite. In the agent, the salt is in mixture with an organic gel forming binder. The mixed material is especially adapted for preparing self-supporting, discrete particles of solid compacted material, e.g., tableted composition. The composition can provide such compacted material not only of desirable strength and hardness, but also of desirably controlled dissolution rate.

Abstract: The instant invention relates to a process and apparatus for treating wastewater containing bentazon by decomposing the bentazon therein and thus eliminating or substantially reducing the bentazon content. This process comprises adjusting the pH of the wastewater to a value of less than 7 and heating it to a temperature of at least about 60.degree. C.

Abstract: A process for treating effluent wherein an oxidizing agent in the effluent is decomposed on contact with a catalyst bed. The oxidizing agent can be a pollutant present in the effluent, for example hypochlorite in the effluent from chlorine-producing brine electrolysis cells or from the scrubbing of chlorine gas. In an alternative the effluent may contain oxidizable pollutants and the oxidizing agent is purposefully added thereto. Passage over the catalyst bed catalyzes the decomposition of the oxidizing agent and oxidizable pollutants.The catalyst bed comprises an intimate mixture of an oxide of Group III, nickel oxide and, optionally, cobalt oxide, supported on pieces of a non-porous substantially inert material.

Abstract: The instant invention relates to a process and apparatus for treating wastewater containing bentazon by decomposing the bentazon therein and thus eliminating or substantially reducing the bentazon content. This process comprises adjusting the pH of the wastewater to a value of less than 7 and heating it to a temperature of at least about 60.degree. C.

Abstract: Fluorine or fluorine compounds dissolved at low concentrations in water are efficiently separated by use of hydrated rare earth oxides or insoluble hydrated rare earth salts, particularly hydrous rare earth fluorides or hydrous rare earth phosphates, as the adsorbent. By bringing fluorine dissolved water of pH 2-7 into contact with said adsorbent, fluorine is adsorbed on the adsorbent, and the adsorbed fluorine can be desorbed by contact with an alkali solution of pH 10 to 14 to regenrate said adsorbent. Also, by addition of a precipitating agent for fluorine to the desorbed solution, fluorine compounds can be separated by precipitation and the filtrate can be reused as the regenerating solution for the adsorbent.