Classifications

• • 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
  • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
  • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
  • C02F1/547—Tensides
• • 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
  • 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
  • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
• • 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

Definitions

• the invention relates to the treatment of waste water, especially weakly contaminated waste water, which contain fluorinated emulsifiers, such as are used in the polymerization of fluorinated monomers, since they have no telogenic properties.
• the salts preferably the alkali or ammonium salts, of perfluorinated or partially fluorinated alkane carboxylic acids or sulfonic acids are used. These compounds are produced by electrofluorination or by the telomerization of fluorinated monomers, which is very expensive. There has been no shortage of attempts to recover these valuable materials from waste water.
• a process for the recovery of fluorinated carboxylic acids in usable form from contaminated starting materials is known from US Pat. No. 5,442,097, where necessary the fluorinated carboxylic acid is released from these materials in an aqueous medium with a sufficiently strong acid, and these are reacted with a suitable alcohol and distilled off the ester formed.
• a polymerization liquor can be used as the starting material, in particular from so-called emulsion polymerization, in which the fluoropolymer is produced in the form of colloidal particles with the aid of relatively high amounts of emulsifier.
• Polymerization liquor is the wastewater that is obtained when the fluoropolymer is isolated by coagulation (without further process steps such as washing). This The process has proven itself very well, but requires a certain concentration of fluorinated carboxylic acid in the starting material.
• Carboxylic acids can also be carried out in the absence of alcohols.
• the fluorocarboxylic acid is distilled off in the form of a highly concentrated azeotrope.
• this method variant is not technically advantageous for energy reasons.
• the resulting wastewater is also more polluted than before treatment.
• DE-A-20 44 986 discloses a process for obtaining perfluorocarboxylic acids from dilute solution, the dilute solution of the perfluorocarboxylic acids being brought into adsorption contact with a weakly based anion exchange resin and thereby the perfluorocarboxylic acid contained in the solution to the anions - Exchange resin adsorbed, the anion exchange resin eluted with an aqueous ammonia solution and thus the adsorbed perfluorocarboxylic acid is converted into the eluent and finally the acid from the eluate is recovered.
• relatively large amounts of dilute ammonia solution are required for complete elution and, moreover, this process is very time consuming.
• fluorinated emulsifier acids which is characterized in that the solids finely divided in the waste water are stabilized with a surfactant or a surface-active substance and then the fluorinated emulsifier acids are bound to an anion exchange resin and the fluorinated emulsifier acids are eluted from this (WO -A-99/62830).
• nonionic surfactants are used in a concentration of 100 to 400 mg / 1.
• a process has now been found for recovering fluorinated emulsifiers from an aqueous phase, this aqueous phase containing small amounts of fluoropolymer particles and optionally further substances in addition to the emulsifier, an upper concentration value of a nonionic surface-active substance being determined, below which no further decrease in the Desorption of the emulsifier bound to an anion exchanger occurs, - the aqueous phase is adjusted to a concentration of nonionic surfactant between the upper concentration value determined in this way or a lower concentration which is still effective to avoid coagulation of the polymer particles, brings the aqueous phase thus adjusted into contact with an anionic exchange resin in order to effect adsorption of the emulsifier on the exchange resin and to release the emulsifier from the exchange resin.
• the suitable concentration of nonionic surface-active agent depends on the type of polymer, on the surface-active agent and optionally on other substances contained in the aqueous phase. It is therefore advisable to determine the appropriate concentration limits on the nonionic surfactant for each wastewater to be treated. Usually a concentration of at most 10 ppm is sufficient, mostly a concentration in the range of 5 to 0.1 ppm.
• fluoropolymers such as polytetrafluoroethylene, fluorothermoplastics and fluoroelastomers
• the polymers are separated by coagulation, these being mechanically subject to high shear ratios or chemically by means of coagulation
• the coagulated fluoropolymers are usually agglomerated and washed with water. This results in relatively high amounts of process waste water, namely usually about 5 to 10 t of waste water per 1 t
• Fluoropolymer Fluoropolymer.
• the fluorinated emulsifier is largely washed out and is thus found in the waste water.
• the concentration is usually a few millimoles per liter, corresponding to about 1000 ppm.
• the wastewater also contains chemicals from the polymerization, such as initiators and buffers, which are approximately of the same order of magnitude as the emulsifier, and very small amounts of fluoropolymer latex particles which have not been coagulated.
• the proportion of these latex particles in the wastewater is usually less than 0.5% by weight.
• Another advantage of the low concentrations of nonionic surfactant is the more effective separation of the latex particles from the anion-exchanged wastewater. These particles are advantageously coagulated with small amounts of organic flocculant, it being found that the amount of flocculant required increases with increasing concentration of nonionic surface-active agent.
• the fluoropolymers obtained in this way, now loaded with small amounts of surface-active agent and flocculant, can be used in building materials and therefore do not have to be worked up or deposited in a complex manner.
• oxethylates and oxpropylates of organic hydroxy compounds are suitable as nonionic surface-active agents, non-aromatic oxalkylates being preferred for reasons of environmental protection. Oxethylates of long-chain alcohols are therefore preferably used.
• the organic flocculants are advantageously cationic products, for example polydiallyldimethylammonium chloride.
• Cationic surfactants such as didecyldimethylammonium chloride can also be used to precipitate the nonionic stabilized latex particles.
• their use on an industrial scale is problematic because, when the precipitation is carried out improperly, the particles are reloaded into cationically stabilized latex particles. This significantly reduces the degree of felling.
• the invention is explained in more detail in the following examples.
• wastewater from mechanically coagulated polymer dispersions which contained approximately 90% by weight of the perfluorooctanoic acid used in the polymerization and latex particles. They are not diluted with washing water from the agglomerated resins.
• the dimensions of the anion exchange column were: height 5 cm, diameter 4 cm, filling quantity 500 ml, flow rate 0.5 to 1 l / h, procedure: from top to bottom.
• a commercially available, strongly basic ion exchanger ® AMPERLITE IRA 402 was used, capacity: 1.2 mmol / ml.
• Polymerization liquor from the polymerization of the terpolymer from tetrafluoroethylene, hexafluoropropene and vinylidene fluoride with 0.3% by weight polymer-latex particles and 0.1% by weight perfluorooctanoic acid.
• a commercial p-octylphenol oxyethylate ® TRITON X 100 was used
• Example 1 is repeated with the modification that a commercially available fatty alcohol polyglycol ether ® GENAPOL X 080 (Hoechst AG) was used as the nonionic surface-active agent.
• Example 2 was repeated, but using a process wastewater ("polymerization liquor") from the polymerization of a copolymer of tetrafluoroethylene with perfluoro (n-propyl-vinyl) ether containing 0.1% by weight of perfluorooctanoic acid and 0.4% by weight. % Polymer latex particles was used.
• Example 2 was repeated, but using a process wastewater ("polymerization liquor”) from the polymerization of a copolymer of tetrafluoroethylene with ethylene with 0.2% by weight of perfluorooctanoic acid and 0.6% by weight of polymer latex particles.
• polymerization liquor a process wastewater from the polymerization of a copolymer of tetrafluoroethylene with ethylene with 0.2% by weight of perfluorooctanoic acid and 0.6% by weight of polymer latex particles.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Water Supply & Treatment (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Separation Of Suspended Particles By Flocculating Agents (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Removal Of Specific Substances (AREA)
• Treatment Of Liquids With Adsorbents In General (AREA)
• Treatment Of Water By Ion Exchange (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)

Applications Claiming Priority (3)

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• 1999
  • 1999-07-17 DE DE19933696A patent/DE19933696A1/de not_active Withdrawn
• 2000
  • 2000-07-11 MX MXPA02000597A patent/MXPA02000597A/es not_active Application Discontinuation
  • 2000-07-11 ES ES00954467T patent/ES2173825T1/es active Pending
  • 2000-07-11 JP JP2001511374A patent/JP3820369B2/ja not_active Expired - Fee Related
  • 2000-07-11 BR BR0012520-2A patent/BR0012520A/pt not_active Application Discontinuation
  • 2000-07-11 CZ CZ2002128A patent/CZ2002128A3/cs unknown
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  • 2000-07-11 AU AU66915/00A patent/AU767303B2/en not_active Ceased
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  • 2000-07-11 TR TR2002/00135T patent/TR200200135T2/xx unknown
  • 2000-07-11 KR KR10-2002-7000664A patent/KR100447479B1/ko not_active IP Right Cessation
  • 2000-07-11 WO PCT/EP2000/006556 patent/WO2001005710A1/de active Search and Examination
  • 2000-07-11 US US10/009,757 patent/US6706193B1/en not_active Expired - Fee Related
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  • 2000-07-11 EP EP00954467A patent/EP1208065A1/de not_active Ceased
  • 2000-07-11 CA CA002379931A patent/CA2379931A1/en not_active Abandoned
  • 2000-07-13 TW TW089113945A patent/TW574151B/zh not_active IP Right Cessation
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