JP2003094052A - Method for adsorbing and recovering emulsifier containing fluorine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for adsorbing and recovering an emulsifier containing fluorine from an emulsifier aqueous solution (A) containing fluorine in a high recovery yield and a short time. SOLUTION: A method uses (n) packed columns (wherein, (n) is 3 to 10) packed with a weak basic anion-exchange resin, connects (n-1) packed columns among those in series, performs adsorption operation by supplying the first packed column with the aqueous solution (A) and performs desorption operation by utilizing a remaining one packed column. The adsorption and recovery method for the emulsifier containing fluorine comprises introducing discharged water into the remaining one packed column completed desorption operation, supplying the next packed column to the first packed column with the aqueous solution (A), and subjecting desorption operation of the first packed column when the emulsifier containing fluorine is detected in the discharged water from a rear end packed column.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for adsorbing and recovering a fluorine-containing emulsifier from an aqueous solution.

[0002]

2. Description of the Related Art Hitherto, there have been known methods for adsorbing and recovering a fluorinated emulsifier from various fluorinated emulsifier aqueous solutions using a weakly basic anion exchange resin (hereinafter referred to as IER).

JP-B-47-51233, US42821
62, DE 2044986 and the like describe a method of adsorbing perfluorooctanoic acid (hereinafter, referred to as PFOA), which is a fluorine-containing emulsifier contained in polymerization wastewater, to an IER and recovering it. In WO99 / 62830, a pretreatment of adding nonionic or cationic surfactant to the polymerization wastewater is carried out to stabilize polytetrafluoroethylene (hereinafter referred to as PTFE) fine particles in the polymerization wastewater, and IE.
A method for preventing clogging of R is described.

WO99 / 62858 describes in advance that PTFE
A method is described in which PFOA is adsorbed and recovered using IER after performing a pretreatment for separating and removing fine particles. In JP-A-55-120630, US5312935 and DE2908001, the polymerization wastewater is concentrated by an ultrafiltration method and a pretreatment for recovering a part of PFOA used for PTFE production is carried out, and then the emulsifier is adsorbed and desorbed by IER. The method of making is described.

JP-A-55-104651, US4282
162 and DE 2903981 disclose a method for desorbing PFOA adsorbed on IER using a mixture of an acid and an organic solvent. JP-A-6-025072, US5
As a method for purifying PFOA desorbed from IER, there is a method of pre-treating PFOA having a water content of 2% or less with an oxidizing agent such as ammonium persulfate and sodium dichromate, and then distilling and isolating the same. It is disclosed.

JP-A-7-053465, EP06320
09 and US 5442097 disclose a method for distilling and isolating an ester compound obtained by reacting PFOA separated from an aqueous solution by adding a strong acid with an alcohol. However, in general, when recovering a fluorine-containing emulsifier such as PFOA using the IER, the exchange zone of the fluorine-containing emulsifier with respect to the IER becomes very long, and the coexisting anions such as chloride ion, sulfate ion, and nitrate ion coexist. Due to the fact that it is competitively adsorbed to the IER with the fluorine emulsifier,
The exchange capacity of R could not be used sufficiently effectively.

For example, when one IER packed column is used, even when 50 mol% or less of the fluorine-containing emulsifier with respect to the total exchange capacity of the IER has been adsorbed, the unadsorbed ER emulsifier is not adsorbed from the IER packed column outlet. Fluorine emulsifier flows out. Therefore IE
The recovery rate of the fluorine-containing emulsifier per unit volume of R was low, and the adsorption / desorption operation required a long time.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for adsorption / recovery of a fluorine-containing emulsifier by IER, which has a high adsorption efficiency.

[0009]

The present invention is a method for adsorbing and recovering a fluorinated emulsifier from an aqueous fluorinated emulsifier solution (A) using IER, wherein n filled with IER (where n is It is an integer of 3 to 10), and (n-1) packed columns among them are connected in series,
In the method in which the aqueous solution (A) is supplied to the first packed column for adsorption operation and the remaining one packed column is used for desorption operation, a fluorinated emulsifier is detected in the outflow water from the last packed column. Then, the effluent is led to the remaining one packed tower after the desorption operation, the aqueous solution (A) is supplied to the packed tower next to the first packed tower, and the desorption of the first packed tower is carried out. Provided is a method for adsorbing / recovering a fluorinated emulsifier, which is characterized by performing an operation.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the adsorption / recovery method of the present invention, n packed columns (where n is an integer of 3 to 10) packed with IER are used. IE less than 3
If the adsorption rate of R per unit volume is not sufficiently high and the number is more than 10, the number of switching valves becomes extremely large, resulting in complicated operation. More preferably, it is 3 to 5.

In the adsorption / recovery method of the present invention, the IER
While using n packed towers filled with, (n-1) packed towers among them are connected in series, the aqueous solution (A) is supplied to the first packed tower to perform adsorption operation, In the method of performing desorption operation in the remaining one packed tower, when a fluorinated emulsifier is detected in the outflow water from the last packed tower, the outflow water is transferred to the remaining one packed tower after the desorption operation. Guide,
The aqueous solution (A) is supplied to the packed tower next to the first packed tower,
And the desorption operation of the first packed tower is performed.

In the adsorption / recovery method of the present invention, the adsorption / desorption / recovery method according to claim 1 is preferably the following operations (1) to (8). (1) The (n-1) packed columns are connected in series to
The aqueous solution (A) is supplied to the packed tower, and the first tower (n-
1) Adsorb the fluorinated emulsifier using (n-1) packed columns up to the column.

(2) When a fluorinated emulsifier is detected in the outflow water from the last (n-1) th packed tower, the supply of the aqueous solution (A) to the first packed tower is stopped and n lead to a packed tower. (3) The aqueous solution (A) is supplied to the second packed tower, and the (n-1) packed towers from the second packed tower to the nth packed tower are used to adsorb the fluorinated emulsifier. (4) An alkaline aqueous solution is supplied to the first packed tower to desorb and recover the fluorine-containing emulsifier.

(5) When a fluorine-containing emulsifier was detected in the outflow water from the last nth packed tower, the supply of the aqueous solution (A) to the second packed tower was stopped, and the outflow water was desorbed. Lead to the first packed column. (6) The aqueous solution (A) is supplied to the third packed tower, and the (n-1) packed towers from the third packed tower to the first packed tower are used to adsorb the fluorinated emulsifier. (7) An alkaline aqueous solution is supplied to the second packed tower to desorb and recover the fluorine-containing emulsifier.

(8) In the same manner as in (1) to (7) below, when a fluorine-containing emulsifier is detected in the outflow water from the last packed tower, the outflow water is led to the packed tower after the desorption operation. Then, the aqueous solution (A) is supplied to the packed tower next to the packed tower to which the aqueous solution (A) has been supplied, and the desorption operation of the packed tower to which the aqueous solution (A) has been supplied is performed. By performing the operation as described above, the fluorinated emulsifier can be adsorbed and recovered in a short time with a high recovery rate with a small amount of IER used, as compared with the case where two or less IER packed columns are used.

As the fluorine-containing emulsifier in the present invention,
Perfluoroalkanoic acid, ω-hydroperfluoroalkanoic acid, ω-chloroperfluoroalkanoic acid, perfluoroalkanesulfonic acid and the like having 5 to 13 carbon atoms are preferable, and these may have a linear structure or a branched structure. It may be a mixture. Moreover, you may contain an ether bond in a molecule. Within this carbon number range, the emulsifying effect is high.

Further, the fluorine-containing emulsifier may be an alkali metal salt such as lithium salt, sodium salt or potassium salt or ammonium salt of the above acid. As salts, ammonium salts and sodium salts are more preferable, and ammonium salts are most preferable.

Specific examples of the acid include perfluoropenta
Acid, perfluorohexanoic acid, perfluoroheptane
Acid, PFOA, perfluorononanoic acid, perfluorode
Canic acid, perfluorododecanoic acid, ω-hydroperflun
Oroheptanoic acid, ω-hydroperfluorooctanoic acid,
ω-hydroperfluorononanoic acid, ω-chloroperflun
Oroheptanoic acid, ω-chloroperfluorooctanoic acid,
ω-chloroperfluorononanoic acid, CF_ThreeCF_TwoCF
_TwoOCF (CF_Three) COOH, CF_ThreeCF_TwoCF_TwoOC
F (CF_Three) CF_TwoOCF (CF_Three) COOH, CF_Three
CF_TwoCF_TwoO [CF (CF _Three) CF_TwoO]_TwoCF (C
F_Three) COOH, CF_ThreeCF_TwoCF_TwoO [CF (C
F _Three) CF_TwoO]_ThreeCF (CF_Three) COOH, CF_ThreeC
F_TwoCF_TwoCF_TwoCF_TwoOCF (CF_Three) COOH, etc.
Perfluorohexanesulfonic acid, perfluorohepta
Sulfonic acid, perfluorooctane sulfonic acid, per
Fluoronane sulfonic acid, perfluorodecane sulfo
Acid, etc. are mentioned.

Specific examples of the ammonium salt include perf.
Ammonium uropentanoate, perfluorohexane
Ammonium acid perfluoroheptanoate
System, ammonium perfluorooctanoate, perfluor
Ammonium rononanoate, Ammo perfluorodecanoate
, Ammonium perfluorododecanoate, ω-hi
Ammonium droper fluoroheptanoate, ω-hydro
Ammonium perfluorooctanoate, ω-hydroper
Ammonium fluorononanoate, ω-chloroperfluor
Ammonium loheptanate, ω-chloroperfluoro
Ammonium citrate, ω-chloroperfluorononane
CF such as ammonium acidate_ThreeCF_TwoCF_TwoOCF (C
F_Three) COONH_Four, CF_ThreeCF_TwoCF_TwoOCF (CF
_Three) CF_TwoOCF (CF_Three) COONH_Four, CF_ThreeCF
_TwoCF_TwoO [CF (CF_Three) CF_TwoO]_TwoCF (C
F_Three) COONH_Four, CF_ThreeCF_TwoCF_TwoO [CF (C
F_Three) CF_TwoO]_ThreeCF (CF_Three) COONH_Four, CF
_ThreeCF_TwoCF _TwoCF_TwoCF_TwoCF_TwoCF_TwoOCF (CF
_Three) COONH_FourEtc., perfluorohexane sulfonic acid
Ammonium, perfluoroheptane sulfonic acid
Ammonium, perfluorooctane sulfonate
Ammonium, perfluorononane sulfonate ammonium, per
Ammonium fluorodecane sulfonate, etc.
It

Specific examples of the lithium salt include lithium perfluoropentanoate, lithium perfluorohexanoate, lithium perfluoroheptanoate, lithium perfluorooctanoate, lithium perfluorononanoate, lithium perfluorodecanoate and perfluorododecane. Lithium acid, ω-hydroperfluoroheptanoate, ω-hydroperfluorooctanoate, ω-
Lithium hydroperfluorononanoate, lithium ω-chloroperfluoroheptanoate, lithium ω-chloroperfluorooctanoate, lithium ω-chloroperfluorononanoate, etc., CF ₃ CF ₂ CF ₂ OCF (CF ₃ ) CO
_{OLi, CF 3 CF 2 CF 2} OCF (CF 3) CF 2 O
CF (CF ₃ ) COOLi, CF ₃ CF ₂ CF ₂ O [C
F (CF ₃ ) CF ₂ O] ₂ CF (CF ₃ ) COOLi,
CF ₃ CF ₂ CF ₂ O [CF (CF ₃ ) CF ₂ O] ₃ C
F (CF ₃ ) COOLi, CF ₃ CF ₂ CF ₂ CF ₂ C
F ₂ CF ₂ CF ₂ OCF (CF ₃ ) COOLi, etc., lithium perfluorohexanesulfonate, lithium perfluoroheptanesulfonate, lithium perfluorooctanesulfonate, lithium perfluorononanesulfonate, lithium perfluorodecanesulfonate, etc. Is mentioned.

Specific examples of the sodium salt include sodium perfluoropentanoate, sodium perfluorohexanoate, sodium perfluoroheptanoate, sodium perfluorooctanoate, sodium perfluorononanoate, sodium perfluorodecanoate and perfluorododecane. Sodium acid, sodium ω-hydroperfluoroheptanoate, sodium ω-hydroperfluorooctanoate, sodium ω-hydroperfluorononanoate, sodium ω-chloroperfluoroheptanoate,
Sodium ω-chloroperfluorooctanoate, sodium ω-chloroperfluorononanoate, etc., CF ₃ CF ₂
CF ₂ OCF (CF ₃ ) COONa, CF ₃ CF ₂ CF
₂ OCF (CF ₃ ) CF ₂ OCF (CF ₃ ) COON
a, CF ₃ CF ₂ CF ₂ O [CF (CF ₃ ) CF ₂ O]
₂ CF (CF ₃ ) COONa, CF ₃ CF ₂ CF ₂ O
[CF (CF ₃ ) CF ₂ O] ₃ CF (CF ₃ ) COON
a, CF ₃ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ OC
F (CF ₃ ) COONa and the like, sodium perfluorohexane sulfonate, sodium perfluoroheptane sulfonate, sodium perfluorooctane sulfonate, sodium perfluorononane sulfonate, sodium perfluorodecane sulfonate and the like can be mentioned.

Specific examples of the potassium salt include perfluor.
Potassium lopentate, potassium perfluorohexanoate
System, potassium perfluoroheptanoate, perfluoro
Potassium citrate, potassium perfluorononanoate,
-Potassium fluorodecanoate, perfluorododecanoic acid
Potassium, Ca-ω-hydroperfluoroheptanoate
Ω-potassium hydroperfluorooctanoate, ω-
Potassium hydroperfluorononanoate, ω-chloroper
Potassium fluoroheptanoate, ω-chloroperfluoro
Potassium octanoate, ω-chloroperfluorononanoic acid
CF such as potassium_ThreeCF_TwoCF_TwoOCF (CF_Three) CO
OK, CF_ThreeCF_TwoCF_TwoOCF (CF_Three) CF_TwoOC
F (CF_Three) COOK, CF_ThreeCF_TwoCF_TwoO [CF
(CF _Three) CF_TwoO]_TwoCF (CF_Three) COOK, CF
_ThreeCF_TwoCF_TwoO [CF (CF _Three) CF_TwoO]_ThreeCF
(CF_Three) COOK, CF_ThreeCF_TwoCF_TwoCF_TwoCF_Two
CF_TwoCF_TwoOCF (CF_Three) COOK, etc.
Rohexanesulfonate potassium, perfluoroheptane
Potassium sulfonate, perfluorooctane sulfonic acid
Potassium, potassium perfluorononane sulfonate, pa
-Potassium fluorodecane sulfonate, etc.
It

Particularly, perfluoroalkanoic acid having 6 to 12 carbon atoms is preferable, and perfluoroheptanoic acid and PFO are preferable.
A, perfluorononanoic acid or perfluorodecanoic acid,
And ammonium salts thereof are more preferred, and PFOA
And their ammonium salts are most preferred.

The IER in the present invention is a weakly basic anion exchange resin. Although the strongly basic anion exchange resin has a high adsorption efficiency of the fluorine-containing emulsifier, it is difficult to recover the target compound by desorption, and the recovery rate is low. The material of the packed tower in the present invention is not particularly limited, and it is preferable that the material has resistance to acidic and alkaline aqueous solutions. Specific examples include stainless steel, fluororesin lining, rubber lining, glass, polyvinyl chloride resin and the like.

The size and shape of the packed column are not particularly limited, but it is preferable that the packed column is cylindrical because internal uniformity is easily obtained. The filling amount of IER is preferably 20 to 80% by volume of the internal volume of the packed column. If it is less than this, the adsorption efficiency is lowered because the ratio of height and width of IER is poor, and if it is more than this, there is a possibility that the IER overflows from the packed column due to the volume change of IER during adsorption / desorption. More preferably, it is 40 to 60% by volume.

The supply direction of the liquid to be adsorbed in the packed column can be appropriately selected from top to bottom, bottom to top depending on the shape of the installation site. The drainage supply rate is preferably 1 to 10 times the volume of the IER per hour. If it is smaller than this, it takes a very long time and is inefficient. It is more preferably 2 to 6 times per hour.

The fluorinated emulsifier aqueous solution (A) in the present invention is not particularly limited as long as it is an aqueous solution in which the fluorinated emulsifier is dissolved, but drainage after collecting and separating useful substances is preferable. In particular, drainage from the step of producing a polymer of a fluorine-containing monomer or a copolymer of a fluorine-containing monomer and a monomer other than the fluorine-containing monomer is more preferable. Here, the wastewater from the production process of the polymer means a fluorine-containing polymer or an aqueous dispersion of a fluoropolymer obtained by emulsion-polymerizing or aqueous-dispersion-polymerizing a fluorine-containing monomer and a monomer other than the fluorine-containing monomer. It means the wastewater after the fluoropolymer is aggregated by salting out and separated. The effluent contains a fluorine-containing emulsifier.

As the fluorine-containing monomer, tetrafluoroethylene (hereinafter referred to as TFE), CF ₂ ═CFC
_{l, CFH = CF 2, CFH} = CH 2, CF 2 = CH 2
Such as fluoroethylene, hexafluoropropylene,
Examples include fluoropropylene such as CF ₂ ═CHCF ₃ . These fluorine-containing monomers may be used alone or in combination of two or more.

As the monomer other than the fluorine-containing monomer, vinyl ester type monomers such as vinyl acetate, ethyl vinyl ether, cyclohexyl vinyl ether,
Vinyl ether monomers such as hydroxybutyl vinyl ether, monomers having a cyclic structure such as norbornene and norbonadiene, allyl ether monomers such as methyl allyl ether, and olefinic monomers such as ethylene, propylene and isobutylene The body is also used. Monomers other than the fluorine-containing monomer may be used alone or in combination of two or more.

As the fluorine-containing polymer, polytetrafluoroethylene, TFE / P copolymer, TFE / P / V
A dF copolymer etc. are mentioned. The method for adsorbing and recovering a fluorine-containing emulsifier of the present invention can be applied not only to a fluorine-containing emulsifier but also to a low molecular weight fluorine-containing carboxylic acid such as trifluoroacetic acid and pentafluoropropanoic acid and / or a salt thereof.

[0031]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto. Examples 1 to 4 and Example 8 are Examples, and Examples 5 to 7 are Comparative Examples. The supply rate of the PFOA test liquid is a space velocity (unit: mL / hour).
Further, high-performance liquid chromatography-mass spectrometry (hereinafter referred to as LC / MS) was used for the analysis of PFOA in the outflow water.

[Example 1] Three glass packed towers having an internal volume of 100 mL were prepared, and 50 mL of IER (IERWA30, manufactured by Mitsubishi Chemical, hereinafter referred to as IERWA30) was packed in each. Of these three packed towers, two of the first packed tower and the second packed tower were connected in series. 90 mL of 10% hydrochloric acid was added to 9000 mL of a 0.1 mass% aqueous solution of PFOA to adjust the pH to 2, and 9090 of a PFOA test solution was added.
mL was obtained. The PFOA test liquid was supplied at 500 mL / hour from the upper part of the first packed column using a tube pump.
Outflow water from the bottom outlet of the second packed column was collected every 30 minutes and analyzed by LC / MS. The pH of the effluent was about 10. PFOA was detected in the effluent after about 24 hours.
At this time, the pH of the outflow water changed to about 4. The supply of the PFOA test liquid was stopped, and the third packed column was connected in series after the second packed column. Then, the PFOA test liquid was supplied from the upper part of the second packed column, and the adsorption operation was continued.

A 0.1 M NaOH aqueous solution was supplied to the first packed column, and PFOA was desorbed. The supply rate of the NaOH aqueous solution was 200 mL / hour. After the operation was completed, 250 mL of ion-exchanged water was passed at 500 mL / hour to regenerate IERWA30. This desorption / regeneration operation took about 8 hours.

While continuing the adsorption operation, the water flowing out from the bottom outlet of the third packed column was sampled and analyzed every 30 minutes. Approximately 12 hours later, PFOA was detected in the effluent, so P
The supply of the FOA test liquid was stopped, and after the third packed column, the first packed column, which had completed the desorption operation, was connected. Then, the PFOA test liquid was supplied from the upper part of the third packed column, and the adsorption operation was continued. The second packed column was subjected to the desorption operation with NaOH as described above.

Thereafter, the same operation is repeated, two of the three packed columns are always connected in series, and the adsorption operation is continued,
The remaining one was used for desorption and regeneration. By this method, all the PFOA test liquids were passed through the packed column. During this time, 1
It took 80 hours. Collect all of the resulting runoff water, and
By analyzing the OA concentration, it was found that 99.0 mass% of PFOA was adsorbed and recovered.

[Example 2] The water flow rate during the adsorption operation was 200 m.
PFOA was adsorbed and recovered from the PFOA test solution in the same manner as in Example 1 except that the L / hour was changed. The required time was 450 hours, and the recovery rate of PFOA was 99.5%. [Example 3] From the PFOA test liquid to PFOA in the same manner as in Example 1 except that the water flow rate during the adsorption operation was changed to 1000 mL / hour.
Was adsorbed and collected. The required time was 90 hours, and the recovery rate of PFOA was 97.0%.

[Example 4] Four glass packed towers having an internal volume of 100 mL were prepared, and 37.5 mL of IERWA30 was packed in each packed tower. Three of the packed towers were connected in series. Using a tube pump, the PFOA test liquid obtained in the same manner as in Example 1 was supplied from the upper part of the first packed column at a rate of 562.5 mL / hour. Outflow water discharged from the bottom outlet of the third packed column was collected and analyzed every 30 minutes. The pH of the effluent was about 10. PFOA was detected in the effluent after about 24 hours. At this time, p of the outflow water
H changed to about 4. The supply of the PFOA test liquid was stopped, and the fourth packed column was connected in series after the third packed column. Then,
The PFOA test liquid was supplied from the upper part of the second packed column, and the adsorption operation was continued.

A 0.1 M NaOH aqueous solution was supplied to the first packed column to carry out the desorption operation of PFOA. The supply rate of the NaOH aqueous solution was 225 mL / hour. After the operation was completed, 187.5 mL of ion-exchanged water was passed through at a rate of 562.5 mL / hour to regenerate IERWA30. This desorption
The regenerating operation took about 8 hours.

While continuing the adsorption operation, the outflow water from the bottom outlet of the fourth packed column was sampled and analyzed every 30 minutes. PFOA was detected in the effluent after about 8 hours.
The supply of the OA test liquid was stopped, and after the fourth packed tower, the first packed tower, which had completed the desorption operation, was connected. Then, the PFOA test liquid was supplied from the upper part of the third packed column, and the adsorption operation was continued.
In addition, the outflow water from the bottom outlet of the first packed tower was sampled and analyzed every 30 minutes. The second packed tower is NaOH as above.
Desorption / regeneration operation was performed with an aqueous solution.

Thereafter, the same operation was repeated, and three of the four packed columns were always connected in series to continue the adsorption operation,
The remaining one was used for desorption and regeneration. By this method, all the PFOA test liquids were passed through the packed column. During this time, 1
It took 60 hours. Collect all of the resulting outflow water, P
By analyzing the FOA concentration, 99.2% of PFOA was obtained.
It was found that mass% was adsorbed and recovered.

[Example 5 (Comparative Example)] One glass packed column having an internal volume of 300 mL was prepared, and 150 pieces of IERWA30 were prepared.
mL was charged. The PFOA test liquid obtained in the same manner as in Example 1 was passed through the packed tower at 750 mL / hour using a tube pump. Outflow water from the bottom outlet of the packed tower was collected and analyzed. PFOA was detected after about 24 hours. At this time, the supply of the PFOA test solution was stopped and 0.1M Na was added.
Desorption operation was performed with an OH aqueous solution. The water flow rate of the aqueous NaOH solution was 300 mL / hour. 25 after completion of desorption operation
0 mL of ion-exchanged water was passed at 450 mL / hour, and I
ERWA30 was regenerated. Approximately 2 for this desorption / regeneration operation
It took 4 hours. Next, the PFOA test liquid was supplied from the upper part of the packed tower, and the outflow water from the bottom outlet of the packed tower was collected and analyzed. PFOA was detected after about 24 hours. PFOA
The water supply of the test liquid was stopped, and the desorption / regeneration operation was carried out in the same manner as above.

Thereafter, the same operation is repeated, and all PFs are
The OA test liquid was passed through the packed tower. During this time, 240 hours were required. When all the resulting outflow water was collected and analyzed for PFOA concentration, it was found that 75.0% of PFOA was adsorbed and collected.

[Example 6 (Comparative Example)] Two glass-filled towers having an internal volume of 200 mL were prepared.
L was filled in each. Example 1 using a tube pump
The PFOA test liquid obtained in the same manner as above was supplied from the upper part of the first packed column at 375 mL / hour. Outflow water from the bottom outlet of the first packed tower was collected and analyzed. PFOA after about 24 hours
Was detected. At this time, first supply the PFOA test solution.
The adsorption operation was continued by switching from the packed tower to the second packed tower.
With respect to the first packed column, desorption operation was performed with a 0.1 M NaOH aqueous solution. Water flow rate of NaOH aqueous solution is 150
mL / hour. After completion of the desorption operation, 375 mL of ion-exchanged water was passed at 375 mL / hour to regenerate IERWA30. It took about 12 hours for the desorption / regeneration operation.

When the effluent discharged from the bottom outlet of the second packed column was collected and analyzed, PFOA was detected after about 24 hours. At this time, the supply of the PFOA test liquid was switched from the second packed tower to the first packed tower after the desorption operation was completed. For the second packed column, the desorption operation was carried out in the same manner as above.

Thereafter, the same operation was repeated, and all the PFOA test liquid was passed through to carry out adsorption / desorption operation. The time required was 264 hours. All of the resulting effluent was collected and analyzed for PFOA concentration.
It was found that OA was adsorbed and collected.

[Example 7 (Comparative Example)] One glass packed column having an internal volume of 400 mL was prepared, and 200 m of IERWA30 was prepared.
L was charged. The PFOA test liquid obtained in the same manner as in Example 1 was treated with a tube pump at 1000 m from the top of the packed column.
Supplied at L / hr. Outflow water discharged from the bottom outlet of the bottom of the first packed column was collected and analyzed. PF in about 24 hours
OA was detected. At this time, the PFOA test solution was stopped, and a desorption operation was performed with a 0.1 M NaOH aqueous solution.
The water flow rate of the aqueous NaOH solution was 400 mL / hour.
After completing the desorption operation, add 1000 mL of ion-exchanged water to 1000
Water was passed at a rate of mL / hour to regenerate IERWA30. It took about 24 hours for the desorption / regeneration operation. Then, the PFOA test liquid was supplied at 1000 mL / hour from the top of the packed tower, and the outflow water from the bottom outlet of the packed tower was collected and analyzed. About 24
PFOA was detected after hours. At this time, the supply of the PFOA test liquid was stopped, and the desorption operation was performed in the same manner as above.

Thereafter, the same operation was repeated, all the PFOA test liquid was passed through, and adsorption / desorption operations were carried out. The time required was 180 hours. All of the resulting effluent was collected and analyzed for PFOA concentration.
OA was adsorbed and collected.

The above results are summarized in Table 1.

[0049]

[Table 1]

Example 1 and Example 5 (Comparative Example) and Example 6 (Comparative Example)
Comparing each of these, the amount of IER used was 150 mL, but in Example 1, the PFOA recovery rate was high and the time required for recovery was about 25% shorter. In order to obtain the time required for recovery equivalent to that in Example 1, as in Example 7 (comparative example), 33.
3% more 200 mL IER was required. Moreover, the recovery rate was high in the examples. IER as in example 4
It was found that increasing the number of packed towers further increased the recovery rate and shortened the recovery time.

[Example 8] PTFE fine particles were removed from the wastewater from the manufacturing process of PTFE to obtain an aqueous solution containing 0.023% by mass of PFOA. 9000mL of this aqueous solution
In the same manner as in Example 1 except that 909 mL of a PFOA test solution obtained by adding 9 mL of a 10% aqueous hydrochloric acid solution was used.
Adsorption and recovery of FOA was performed. The recovery time was 180 hours and the recovery rate was 96.5%.

[0052]

According to the adsorption / recovery method of the present invention, the fluorine-containing emulsifier can be recovered at a higher recovery rate than the aqueous solution of the fluorine-containing emulsifier. Also, the time required for adsorption / recovery can be shortened, and IE
It is possible to reduce the amount of R used.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroki Kamiya             Asahi Glass Co., Ltd. 10 Goi Coast, Ichihara City, Chiba Prefecture             In the company F-term (reference) 4D024 AA04 AB04 BA17 BC02 DA08                 4D025 AA09 AB35 AB38 BA15 BB02                       BB09 CA02

Claims (2)

[Claims] 1. A method for adsorbing and recovering a fluorinated emulsifier from an aqueous fluorinated emulsifier solution (A) using a weakly basic anion exchange resin, wherein the ion-exchange resin is filled with n.
(Here, n is an integer of 3 to 10.) A number of packed towers are used, and (n-1) packed towers among them are connected in series to obtain the first aqueous solution (A). In the method of supplying to a packed tower and performing adsorption operation, and desorbing operation in the remaining one packed tower, when a fluorine-containing emulsifier is detected in the outflow water from the last packed tower, the outflow water is desorbed as described above. Is introduced into the remaining one packed tower after completion of the above, the aqueous solution (A) is supplied to the packed tower next to the first packed tower, and the desorption operation of the first packed tower is performed. Fluorine emulsifier adsorption / collection method. 2. The adsorption and desorption / recovery operations are described in (1) below.
The adsorption / recovery method according to claim 1, which is an operation of (8) to (8). (1) The (n-1) packed columns are connected in series to
The aqueous solution (A) is supplied to the packed tower, and the first tower (n-
1) Adsorb the fluorinated emulsifier using (n-1) packed columns up to the column. (2) When a fluorine-containing emulsifier is detected in the outflow water from the last (n-1) th packed tower, the supply of the aqueous solution (A) to the first packed tower is stopped, and the outflow water is removed from the nth packed tower. Lead to. (3) The aqueous solution (A) is supplied to the second packed tower, and the (n-1) packed towers from the second packed tower to the nth packed tower are used to adsorb the fluorinated emulsifier. (4) An alkaline aqueous solution is supplied to the first packed tower to desorb and recover the fluorine-containing emulsifier. (5) When a fluorine-containing emulsifier is detected in the outflow water from the last nth packed tower, the supply of the aqueous solution (A) to the second packed tower is stopped, and the outflow water is first filled after the desorption. Lead to the tower. (6) The aqueous solution (A) is supplied to the third packed tower, and the (n-1) packed towers from the third packed tower to the first packed tower are used to adsorb the fluorinated emulsifier. (7) An alkaline aqueous solution is supplied to the second packed tower to desorb and recover the fluorine-containing emulsifier. (8) In the same manner as in (1) to (7) below, if a fluorinated emulsifier is detected in the outflow water from the last packed tower,
The effluent is led to the packed tower after the desorption operation, the aqueous solution (A) is supplied to the packed tower next to the packed tower that has been supplied with the aqueous solution (A), and the aqueous solution (A) is supplied until then. Detach the packed tower.