Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J41/00—Anion exchange; Use of material as anion exchangers; Treatment of material for improving the anion exchange properties
  • B01J41/04—Processes using organic exchangers
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/42—Separation; Purification; Stabilisation; Use of additives
  • C07C51/47—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/10—Inorganic compounds
  • C02F2101/12—Halogens or halogen-containing compounds
  • C02F2101/14—Fluorine or fluorine-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
  • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
  • C02F2103/38—Polymers

Definitions

• the invention relates to a process for the elution of fluorinated emulsifiers from anion exchange resins in a basic medium, which is particularly useful for the purification of waste water which originates from the production of fluoropolymers.
• Fluoropolymers such as fluoroelastomers, fluorothermoplastics and polytetrafluoroethylene (PTFE) are produced by aqueous radical emulsion polymerization. Emulsion polymerization requires highly fluorinated emulsifiers to ensure satisfactory colloid stability. The emulsifiers used should not react with the fluoropolymer radicals and should therefore not be telogenic. APFOS, the ammonium salt of perfluorooctanoic acid (PFOS), is usually used.
• the polymerization is followed by isolating the polymer by coagulating the polymer dispersion either mechanically at high shear rate or chemically by adding strong mineral acids such as HC1 or HN0 3 .
• the coagulated fluorothermoplastics are usually agglomerated by adding organic, usually water-immiscible, solvents, for example gasoline or fluorinated hydrocarbons.
• the isolated polymer resins are washed with water. With 5 to 10 t of water consumption per ton of resin, relatively large amounts of process water are obtained, which is referred to here as waste water.
• the wastewater contains 30 to 1000 ppm PFOS on average.
• Characteristic of the coagulation of fluorinated emulsifiers Fluoropolymer is that the emulsifier is highly desorbed during coagulation and is washed out to a very large extent. In this way, more than 80% of the fluorinated emulsifier used ends up in the wastewater.
• this waste water contains the auxiliaries of the various polymerization recipes, such as buffers, initiators and various chain transfer agents, for example diethyl malonic ester and its decomposition products, alkyl chlorides or alkanes, gasoline and other organic compounds from the workup.
• the fluorinated emulsifier particularly APFOS, is a very expensive compound and contributes very significantly to the total cost of the fluoropolymers from the emulsion polymerization. As a result, its recovery is very important for economic reasons.
• fluorinated emulsifiers are practically non-biodegradable and, according to recent studies, there is a suspicion of a health hazard.
• Anion exchangers are recommended.
• the anion exchange is hindered by the presence of fluoropolymer latex particles which clog the anion exchange columns.
• the latex particles are added by adding relatively high amounts of salt before Ion exchange failed.
• the fine latex particles are stabilized by the addition of nonionic surfactants, and this prevents the anion exchange column from becoming blocked, even during continuous operation.
• the removal of the emulsifier from the wastewater with an anion exchange resin is very efficient. Practically quantitative removal takes place in particular with strongly basic anion exchange resins.
• the emulsifier is selectively adsorbed so that the entire capacity of the ion exchanger can be used.
• EP-B-14 431 is one
• Peak concentration of 180,000 ppm can be achieved with an eluent composed of 89% by weight of methanol, 4% by weight of sulfuric acid and 7% by weight of water. Elution takes place in an acidic environment.
• fluorinated emulsifiers in particular PFOS
• a method for eluting fluorinated emulsifiers in which weakly to moderately basic anion exchange resins loaded with fluorinated emulsifiers, in particular PFOS, are eluted with water-miscible organic solvents containing ammonia.
• the 180,000 ppm which can be achieved in the prior art can be significantly exceeded, for example more than 300,000 ppm, with technically simple eluent mixtures.
• the present invention enables significantly higher peak concentrations, thereby significantly reducing the amount of one required for regeneration
• Anion exchange resin required easily flammable organic solvent.
• the organic solvent including the ammonia
• the distillate mixture can be used directly to regenerate the ion exchanger.
• the organic contaminants from the waste water such as chain transfer agents or petrol, are removed from the eluate without any problems from the work-up when the organic solvent is removed, since the salts of the PFOS are not volatile in water vapor.
• the present invention represents a technical process for the recovery of the PFOS from industrial wastewater. Recycling in the sense of the present invention consists in providing the emulsifier which is free from impurities which interfere with the polymerization.
• the ammonia concentration in the mixture is advantageously at least 0.1 mol / 1 and at most 4 mol / 1, preferably 1 to 2.5 mol / 1.
• the ammonia concentration is expediently prepared by adding appropriate amounts of aqueous concentrated ammonia solutions, as commercially available, to the organic solvent.
• the system must contain a sufficient amount of water for the necessary anions to be released.
• Suitable organic solvents are miscible with water and should have a boiling point below 150 ° C., preferably below 110 ° C. "Miscible” is preferably understood to mean “unlimited miscible”.
• Preferred solvents which can be used individually or in a mixture are alkanols having 1 to 4 carbon atoms, acetone, dialkyl ethers of monoglycol and diglycol, where alkyl groups are understood to mean methyl or ethyl.
• Particularly preferred solvents are methanol, ethanol, n- and iso-propanol and dimethyl monoglycol ether.
• the essential cation is the ammonium ion.
• the addition of alkali hydroxides leads to higher eluate concentrations.
• Medium-strength anion exchangers are preferred because of their good effectiveness in removing APFOS from industrial waste water, especially in the presence of nonionic emulsifiers described in German patent application 199 33 696.2 of July 17, 1999.
• This inventive method can basically be carried out with all fluorinated anionic emulsifiers. It relates essentially to fluorinated alkane carboxylic and alkane sulfonic acids, the alkyl radical being partially or preferably completely fluorinated and generally linear or branched.
• the fluorinated emulsifier can also contain [(CF 2 ) n -0] groups with n ⁇ 2. These fluorinated emulsifier acids can also be eluted by the process according to the invention. Mixtures of the fluorinated emulsifier acids mentioned can also be adsorbed and eluted, in particular those which contain PFOS as the main constituent.
• Wash water eluate of the loaded ion exchanger is 5 ppm PFOS. Elution with 1 mol / 1 aqueous ammonia solution shows a peak concentration of 76,000 ppm.
• Wash water eluate of the loaded ion exchanger has a PFOS concentration of 18 ppm.
• the peak concentration is 16,000 ppm.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Treatment Of Water By Ion Exchange (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Treatment Of Liquids With Adsorbents In General (AREA)

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Applications Claiming Priority (2)

Publications (1)

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Cited By (4)

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Citations (3)

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• 1999
  • 1999-11-05 DE DE19953285A patent/DE19953285A1/de not_active Withdrawn
• 2000
  • 2000-10-28 JP JP2001534724A patent/JP2003512931A/ja not_active Ceased
  • 2000-10-28 WO PCT/EP2000/010638 patent/WO2001032563A1/de not_active Ceased
  • 2000-10-28 CA CA002387781A patent/CA2387781A1/en not_active Abandoned
  • 2000-10-28 AU AU79240/00A patent/AU7924000A/en not_active Abandoned
  • 2000-10-28 RU RU2002111410/15A patent/RU2255807C2/ru not_active IP Right Cessation
  • 2000-10-28 US US10/110,643 patent/US6642415B1/en not_active Expired - Fee Related
  • 2000-10-28 CN CNB008154090A patent/CN1174924C/zh not_active Expired - Fee Related
  • 2000-10-28 PL PL00354617A patent/PL354617A1/xx unknown
  • 2000-10-28 EP EP00969564A patent/EP1240107B1/de not_active Expired - Lifetime
  • 2000-10-28 DE DE50002876T patent/DE50002876D1/de not_active Expired - Fee Related
• 2002
  • 2002-05-02 ZA ZA200203488A patent/ZA200203488B/en unknown

Patent Citations (3)

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