Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B11/00—Oxides or oxyacids of halogens; Salts thereof
  • C01B11/20—Oxygen compounds of bromine
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2/00—Disinfection or sterilisation of materials or objects, in general; Accessories therefor
  • A61L2/16—Disinfection or sterilisation of materials or objects, in general; Accessories therefor using chemical substances
  • A61L2/18—Liquid substances
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B7/00—Halogens; Halogen acids
  • C01B7/09—Bromine; Hydrogen bromide
  • C01B7/096—Bromine
• • 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
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/76—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
  • C02F1/766—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens by means of halogens other than chlorine or of halogenated compounds containing halogen other than chlorine
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/395—Bleaching agents
  • C11D3/3951—Bleaching agents combined with specific additives
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2202/00—Aspects relating to methods or apparatus for disinfecting or sterilising materials or objects
  • A61L2202/10—Apparatus features
  • A61L2202/11—Apparatus for generating biocidal substances, e.g. vaporisers, UV lamps

Definitions

• the present invention relates to formulations used in biofouling control in industrial water systems. More specifically, the present invention relates to methods of preparing stable oxidizing bromine formulations and their use in biofouling control in industrial water systems .
• bromine While elemental liquid bromine is an effective biocide, its low solubility ( ⁇ 4g/l00g water) , low boiling point (54.3°C), high vapor pressure (214 mm Hg at 25°C) and extreme corrosivity limit its use as a biocide in industrial applications.
• Another oxidizing bromine compound, bromate has very little antimicrobial activity. Bromate is also very toxic to mammals and is a suspected carcinogen. Nonoxidizing inorganic bromine compounds, such as bromide, have little or no antimicrobial activity.
• a mixture of an aqueous bromine solution and a bromine stabilizer has been used to generate stable oxidizing bromine compounds for use as a biocide.
• An unstabilized aqueous bromine solution is very acidic, unstable and emits very pungent bromine fumes.
• the concentration of stabilized hypobromite solution that can be made from liquid bromine has been limited due to the low solubility of bromine in water.
• an oxidizer such as hypochlorite
• hypochlorite be added to activate the bromide to hypobromite.
• a halogen stabilizer such as sulfamate.
• NaOCl NaOCl
• bromine stabilization Also known are methods of generating bromine for on- site use. Such processes involve electrolytically converting bromate into active bromine compounds such as bromine, hypobromous acid, hypobromite ion and hydrogen tribromide under acidic conditions. However, because the above process generates bromine for on-site use, methods or measures for optimizing bromine stabilization are not addressed.
• the present invention satisfies the aforementioned needs by providing a method of generating a stable oxidizing bromine compound which includes the steps of mixing an alkali or alkaline earth metal bromide and an alkali or alkaline earth metal bromate in water to provide an aqueous solution, cooling the solution to a temperature of less than 25°C, preferably less than 20°C and more preferably less than 10°C, and thereafter adding a halogen stabilizer to the solution, the halogen stabilizer being selected from the group consisting of R- NH 2 , R-NH-R 1 , R-S0 2 -NH 2 , R-CO-NH 2 , R-CO-NH-R 1 and R-CO-NH-CO-R 1 wherein R is a hydroxy group, an alkyl group or an aromatic group and R is an alkyl group or an aromatic group.
• Preferred halogen stabilizers include saccharin, benzenesulfonamide urea, thiourea, creatinine, cyanuric acids, alkyl hydantoins, mono or diethanolamine, organic sulfonamides, biuret, sulfamic acid, organic sulfamates and melamine. Sulfamic acid is the most preferred halogen stabilizer.
• the halogen stabilizer is added to the solution in a molar amount approximately equal to the combined molar amount of alkali or alkaline earth metal bromide and alkali or alkaline earth metal bromate.
• the step of adding the halogen stabilizer results in the solution having a pH of less than 2.
• the method comprises agitating the solution for a time period of greater than 5 minutes after the step of adding the halogen stabilizer.
• the method comprises adjusting the solution to a pH of greater than 13 through the addition of alkali or alkaline earth metal hydroxide after the step of adding the halogen stabilizer.
• the step of mixing the alkali or alkaline earth metal bromide and alkali or alkaline earth metal bromate further comprises mixing the alkali or alkaline earth metal bromide and alkali or alkaline earth metal bromate in a molar ratio of alkali or alkaline earth metal bromide :bromate of about 2:1.
• the method of the present invention provides a stable oxidizing bromine compound which includes the steps of mixing about 2 moles of alkali or alkaline earth metal bromide and about 1 mole of alkali or alkaline earth metal bromate in water to provide an aqueous solution, followed by the step of cooling the solution to a temperature of less than 10°C, followed by the step of adding an acidic halogen stabilizer to the solution to lower the pH of the solution to less than 2, the acidic halogen stabilizer being selected from the group consisting of R-NH 2 , R-NH- R 1 , R-S0 2 -NH 2 , R-SOa-NHR 1 , R-CO-NH 2 , R-CO-NH-R 1 and R-CO-NH- CO-R 1 wherein R is a hydroxy group, an alkyl group or an aromatic group and R is an alkyl group or an aromatic group.
• Preferred halogen stabilizers include urea, thiourea, creatinine, cyanuric acids, alkyl hydantoins, mono or di ethanolamine, organic sulfonamides, biuret, sulfamic acid, organic sulfamates and melamine.
• the acidic halogen stabilizer is added to the solution in a molar amount approximately equal to a combined molar amount of alkali or alkaline earth metal bromide and alkali or alkaline earth metal bromate, followed by the step of agitating the solution for a time period of greater than 5 minutes, followed by the step of adding an alkali or alkaline earth metal hydroxide to the solution to increase the pH of the solution to a level greater than 13.
• the method of the present invention provides a method of preparing a stable oxidizing bromine compound which includes the steps of preparing a caustic solution comprising a halogen stabilizer, water and an alkali or alkaline earth metal hydroxide, adding bromine or bromine chloride to the solution while agitating the solution and cooling the solution.
• the halogen stabilizer is selected from the group consisting of R-NH 2 , R-NH-R 1 , R-S0 2 -NH 2 , R- R-CO-NH 2 , R-CO-NH-R 1 and R-CO-NH-CO-R 1 wherein R is a hydroxy group, an alkyl group or an aromatic group and R 1 is an alkyl group or an aromatic group.
• Preferred halogen stabilizers include saccharin, benzenesulfonamide urea, thiourea, creatinine, cyanuric acids, alkyl hydantoins, mono or di ethanolamine, organic sulfonamides, biuret, sulfamic acid, organic sulfamates and melamine.
• the caustic solution has a pH greater than 13 after the addition of the bromine or bromine chloride .
• the step of adding bromine or bromine chloride is further characterized as adding bromine or bromine chloride in a molar amount approximately equal to the molar amount of halogen stabilizer and approximately equal to one-half of the molar amount of alkali or alkaline earth metal hydroxide.
• the solution is cooled to a temperature of less than 25°C.
• the step of adding bromine or bromine chloride is performed without exposing the bromine to air.
• an alkali or alkaline earth metal hydroxide is added to the solution after the addition of bromine or bromine chloride to increase the pH of the solution above 13.
• the method of the present invention provides a method of preparing a stable oxidizing bromine compound in an aqueous solution which includes the steps of dissolving an alkali or alkaline earth metal bromate salt in water to form a solution, followed by the step of adding a halogen stabilizer to the solution, the halogen stabilizer being selected from the group consisting of R-NH 2 , R-NH-R 1 , R-S0 2 -NH 2 , R-S0 2 - NHR 1 , R-CO-NH 2 , R-CO-NH-R 1 and R-CO-NH-CO-R 1 wherein R is a hydroxy group, an alkyl group or an aromatic group and R 1 is an alkyl group or an aromatic group.
• halogen stabilizers include saccharin, benzenesulfonamide urea, thiourea, creatinine, cyanuric acids, alkyl hydantoins, mono or di ethanolamine, organic sulfonamides, biuret, sulfamic acid, organic sulfamates and melamine.
• bromine or bromine chloride is added to the solution.
• a step of cooling the solution to a temperature of less than 25°C, preferably less than 15°C and more preferably less than 10°C, is performed simultaneously with the step of adding the bromine to the solution.
• the present invention provides an aqueous biocide solution containing a stable oxidizing bromine formulation.
• the solution comprises at least one oxidizing bromine compound selected from the group consisting of " S0 3 NHBr and
• the.base in the solution is an alkali or alkaline earth metal hydroxide.
• Another advantage of the present invention is that it provides a method for generating water soluble solid stable oxidizing bromine compounds.
• Still another advantage of the present invention is that it provides a method for generating stable oxidizing bromine compounds without unwanted by-products such as high levels of bromate.
• Still another advantage of the present invention is that the method of the present invention does not generate chloride and therefore the method of the present invention provides stable oxidizing bromine formulations that are less corrosive.
• Yet another advantage of the present invention is that it provides stable oxidizing bromine compounds that are safer to transport and that are non-acidic.
• Yet another advantage of the present invention is that it generates stable oxidizing bromine compounds for biofouling control in industrial water systems that are more compatible with other water treatment chemicals than unstabilized oxidizing bromine compounds.
• the industrial water systems include cooling water systems, cooling ponds, reservoirs, sweetwater applications, decorative fountains, pasteurizers, evaporative condensers, hydrostatic sterilizers and retorts, gas scrubber systems and air washer systems.
• Another advantage of the present invention is that it provides an improved method of biofouling control in pulp and paper processing systems.
• Another advantage of the present invention is that it provides an improved method of biofouling control occurring on the surfaces of equipment in contact with produced oil field waters.
• Another advantage of the present invention is that it provides an improved method of biofouling control in a food processing system.
• Yet another advantage of the present invention is that it provides improved biofouling control in a beverage processing system.
• Still another advantage of the present invention is that it provides improved biofouling control in a recreational water system.
• Another advantage of the present invention is that it provides an improved method of disinfecting a hard surface .
• Another advantage of the present invention is that it provides an improved bleaching method for the laundering of soiled garments and for the manufacture of cellulosic materials.
• Another advantage of the present invention is that it provides an improved method of washing food items, such as fruit and other food items.
• Other objects and advantages of the present invention will be apparent upon a review of the following detailed description and appended claims.
• the present invention provides a plurality of formulations and methods for generating a wide concentration of stable oxidizing bromine compounds for biofouling control in cooling water and other industrial systems .
• the strategy employed by the present invention utilizes a mixture of alkali or alkaline earth metal bromide and alkali or alkaline earth metal bromate in water as the bromine source .
• Bromate also serves as an oxidizing agent.
• the molar ratio of bromide to bromate is optimally 2:1.
• the solution is then cooled to a temperature preferably of less than 25°C and even more preferably of less than 10°C.
• An acidic stabilizer or acidic stabilizing solution, such as sulfamic acid is then added to the solution to lower the pH of the solution to less than 2. Additional stabilizer is then added to achieve equal molar amounts relative to bromine for optimal stabilization. Without being limited by theory, the following reactions are believed to occur:
• reaction (1) to reaction (3) occurs sequentially with respect to each other.
• an oxidizing bromine stabilizer and correct bromide to bromate ratio are believed to prevent the formation of bromine according to the following reaction: 5NaBr + NaBr0 3 + 6H + > 3Br 2 + 6Na + + 3 H 2 0 (4) If reaction (4) were to happen instead of reaction
• reaction yield is higher than 50%.
• more than 80% of the bromine source was converted to oxidized bromine forms. Accordingly, the reaction yield of at least 80% was achieved.
• reaction time for reactions 1-3 at a pH of less than 2 ranges from 5 to 10 minutes with good agitation. If the product is not going to be used immediately, a strong base, such as NaOH, is added to raise the product pH to a level greater than 13 making the product thermally stable. During the pH adjustment, temperature control is important because the temperature increase by the heat generated from the acid-base reaction can cause the product to decompose. Accordingly, cooling may be necessary.
• a strong base such as NaOH
• the product made with the above process has good thermostability and a high total available halogen concentration, as high as 34% as Br 2 .
• synthesis of a stable oxidizing bromine product in accordance with the above- described method is carried out by mixing 21.2 grams of NaBr0 3 , 32.8 grams of NaBr and 100 grams of water, cooling the solution to 3°C, adding 48 grams of sulfamic acid to the solution and agitating the solution for 10 minutes.
• synthesis of stable oxidizing bromine formulations in accordance with the above-described method is carried out by mixing 21.2 grams of NaBr0 3 , 32.8 grams of NaBr and 100 grams of water in a reactor, cooling the solution to 3°C, adding 44 grams of sulfamic acid to the solution and agitating the solution for 10 minutes, slowly adding 43 grams of 50% aqueous NaOH while controlling the reactor temperature between 3°C and 14°C.
• the resulting product was a golden yellow solution with a pH of 14.11 and available halogen concentration of 27.7% as Br 2 .
• the theoretical Br 2 % is 31.2 if all of the bromine sources
• liquid bromine is used as both oxidizer and bromine source.
• Sulfamate or other nitrogen base compounds are used as stabilizers.
• an adequate amount of alkali or alkaline earth metal hydroxide is required to maintain product pH.
• Formulation temperature is also extremely critical in insuring the formation of stable oxidizing bromines.
• a caustic stabilizing solution is prepared by mixing sulfamic acid, water and alkali or alkaline metal hydroxides (preferably NaOH, Mg(OH) 2 or other hydroxides) .
• the pH of the alkali or alkaline earth metal sulfamate solution is higher than 14.
• Excess hydroxides are purposely added to neutralize the acids generated by the subsequent bromination step and to maintain a high pH (preferably greater than 13) in the finished product.
• the preferred molar ratio of sulfamate to liquid bromine is 1:1.
• the preferred molar ratio of hydroxide to liquid bromine is 2.2:1.
• the stabilizer solution can also be obtained by dissolving alkali or alkaline metal sulfamate in water and adding an appropriate amount of hydroxide .
• the process is normally carried out in a jacketed glass reactor equipped with a proper mixing device.
• a cooling system for the reactor should be set up so that the reactor temperature can be controlled at an optimal range.
• An excessively high reaction temperature during the bromination step will accelerate sulfamate hydrolysis and cause decomposition of the desired product.
• the second step of the process is to slowly add liquid bromine into the stabilizer solution under good agitation. Bromine is preferably added directly into the
• the addition rate is controlled so that the reaction temperature is preferably below 25°C. The higher the reaction temperature, the lower the product yield. If the reaction temperature gets over 35 °C, sulfamate will start hydrolyzing into sulfate and ammonium. The resulting ammonium will react with and consume hypobromite and produce nitrogen gas which can be observed as vigorous foaming. With proper addition rates of liquid bromine, the liquid bromine will react instantaneously and will be stabilized. The process does not produce detectable bromine fumes .
• the product made with the above-described process was found to include no detectable bromate (less than 50 ppm with ion chromatography analysis) ; no detectable product concentration change was observed during a 2 month storage period at room temperature. For a 16.2%
• the product has a half life of 74.5 days at 57°C.
• synthesis of a stable oxidizing bromine product using the above-described method is achieved by mixing 52.16 grams of sulfamic acid, 42.0 grams of water and 128.0 grams of 50% aqueous
• the present invention provides a solid stable oxidizing bromine product which is water soluble.
• the solid product obtained in the above example has a very high concentration of stable oxidizing bromine compounds .
• the remaining content is believed to be water, excess NaOH and NaBr.
• the process can be carried out by dissolving bromate salt and water, adding sulfamate or other stabilizer to the solution, slowly adding liquid bromine, adjusting the pH to a level greater than 13 by adding NaOH, if the resulting product is to be stored for a long period of time.
• the process should be conducted at a temperature less than 25°C, especially during the addition of liquid bromine .
• the stable oxidizing bromine compound of the present invention can be used to provide improved biofouling control in industrial water systems, pulp and paper processing systems, food and beverage processing systems and recreational water systems.
• the stable oxidizing bromine compound of the present invention can also be used as a bleaching agent and to disinfect a hard surface.
• the present invention may be added to an aqueous media used to transport food through various processing systems and also to disinfect process equipment and waste water streams .

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• Wood Science & Technology (AREA)
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• Hydrology & Water Resources (AREA)
• General Chemical & Material Sciences (AREA)
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• Agricultural Chemicals And Associated Chemicals (AREA)
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