A method for decomposing organic fluorine compounds in fluorine-containing waste water
By concentrating and drying fluoride-containing wastewater and reacting it with a sodium metal dispersion, inorganic products sodium fluoride and carbonaceous materials are generated. This solves the problems of high energy consumption and toxic gas generation in high-temperature incineration, and realizes efficient recovery of fluoride resources and resource utilization of waste.
Patent Information
- Application Number
- CN202610702169.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-21
- Publication Date
- 2026-06-19
AI Technical Summary
Existing technologies are insufficient for efficiently decomposing organic fluorine compounds in fluoride-containing wastewater under mild conditions, and high-temperature incineration methods are energy-intensive, produce toxic gases, and waste fluorine resources.
Fluorine-containing wastewater is concentrated and dried to form micro-powder, which reacts with sodium metal dispersion in an inert solvent to decompose and generate inorganic products sodium fluoride and carbonaceous materials, thus realizing the recovery of fluorine resources.
It achieves efficient decomposition of fluorine-containing organic compounds under mild conditions, with a high recovery rate of fluorine resources, avoids the generation of toxic gases, and is suitable for industrial application.
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Abstract
Description
Technical Field
[0001] This application relates to the field of fluoride wastewater decomposition technology, specifically to a method for decomposing organic fluorine compounds in fluoride-containing wastewater. Background Technology
[0002] Fluorinated elastomers, such as perfluoroether elastomers, are widely used in semiconductor manufacturing and many other fields due to their excellent chemical and heat resistance. The production process of fluorinated elastomers generates large amounts of wastewater containing fluorinated organic compounds and polymers. The high chemical stability of these fluorinated compounds makes them extremely difficult to degrade in the environment, earning them the title of "permanent chemicals" and posing a potential threat to the ecological environment and human health. Currently, the main method for treating these fluorinated wastes is high-temperature incineration. However, high-temperature incineration not only consumes a large amount of energy but may also produce highly toxic hydrogen fluoride (HF) gas and other harmful byproducts, causing secondary pollution. Furthermore, fluorine is difficult to effectively recover during high-temperature incineration, leading to the waste of valuable fluorine resources.
[0003] In recent years, technologies for the decomposition and fluorine recovery of fluorinated organic compounds have received increasing attention. Some methods have been reported, such as decomposition at temperatures above 500 °C. However, high-temperature methods are energy-intensive and require demanding equipment; existing metal reduction methods still have many shortcomings in terms of fluorine recovery efficiency, mild reaction conditions, operational safety, and practical applicability, making industrial-scale promotion difficult.
[0004] Therefore, developing a method that can efficiently, safely, and economically decompose fluorinated organic compounds and polymers in wastewater under mild conditions (such as normal temperature and pressure) is of great significance for achieving the sustainable recycling of fluorine resources.
[0005] Based on this, the present invention provides a new technical solution. Summary of the Invention
[0006] In view of this, embodiments of this specification provide a method for decomposing organofluorine compounds in fluoride-containing wastewater and for treating and recycling fluoride-containing organic and polymer wastewater under mild conditions.
[0007] This specification provides the following technical solution through its embodiments: a method for decomposing organic fluorine compounds in fluoride-containing wastewater, comprising: S1. Fluorine-containing organic compounds and polymer powders are obtained by concentrating and drying fluorine-containing wastewater. S2. Disperse metallic sodium in an inert organic solvent to form a metallic sodium dispersion; S3. The fluorinated organic compound and polymer powder are mixed with the sodium metal dispersion to carry out a decomposition reaction; S4. After separating the products of the decomposition reaction in S3, inorganic sodium fluoride and carbonaceous materials are obtained.
[0008] Optionally, in S1, the concentration includes concentration by means of adsorption or centrifugation.
[0009] Optionally, in S1, the drying method for the fluoride-containing wastewater is specifically vacuum drying.
[0010] Optionally, in S1, the particle size of the fluorinated organic compound and polymer powder is 10-120 mesh.
[0011] Optionally, in S2, the inert organic solvent is at least one of mineral oil, tetrahydrofuran, diethyl ether, toluene, and xylene.
[0012] Optionally, in S2, the sodium metal is chopped and added to an inert organic solvent, stirred, and a sodium metal dispersion is formed under the action of high-speed shear force.
[0013] Optionally, in S2, the molar ratio of the metallic sodium to the fluorine in the fluorine-containing organic matter and polymer micropowder is 1.5-3:1.
[0014] Optionally, in S3, the decomposition reaction temperature is 0-40 ℃ and the reaction time is 5-10 h.
[0015] Optionally, in S3, after the decomposition reaction is completed, pure water is added dropwise to the reaction solution until no more bubbles are generated, in order to remove residual metallic sodium.
[0016] Optionally, in S4, the products of the decomposition reaction are sequentially filtered, centrifuged, washed, and dried to obtain inorganic product sodium fluoride and carbonaceous material.
[0017] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least: The innovative technical solution of this application transforms fluorinated organic polymers and other impurities in wastewater into powder through concentration and drying. This powder then reacts fully with metallic sodium in an inert solvent to decompose the powder, ultimately yielding inorganic products sodium fluoride and carbonaceous materials. This avoids the problem of toxic gases generated by traditional high-temperature incineration and decomposition. It achieves the full decomposition of fluorinated organic polymers in wastewater under mild conditions, while simultaneously converting fluorine into sodium fluoride and carbon components into carbonaceous materials. This enables efficient recovery of fluorine resources and resource utilization of solid waste. The method features mild reaction conditions, low energy consumption, safe operation, and high fluorine recovery rate, making it suitable for industrial application. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, they can also make connections based on these accompanying process diagrams without creative effort.
[0019] Figure 1 This is a process flow diagram of a method for decomposing organic fluorine compounds in fluoride-containing wastewater according to this application. Detailed Implementation
[0020] The embodiments of this application will now be described in detail with reference to the accompanying drawings.
[0021] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0022] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and that two or more of these aspects can be combined in various ways. Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be undertaken without these specific details.
[0023] This specification provides an embodiment of a method for decomposing organic fluorine compounds in fluoride-containing wastewater, comprising: S1, concentrating and drying the fluoride-containing wastewater to obtain fluoride-containing organic compounds and polymer powder; S2. Disperse metallic sodium in an inert organic solvent to form a metallic sodium dispersion; S3. The fluorinated organic compound and polymer powder are mixed with the sodium metal dispersion to carry out a decomposition reaction; S4. After separating the products of the decomposition reaction in S3, inorganic sodium fluoride and carbonaceous materials are obtained.
[0024] In S1, the concentration process includes concentration by means of adsorption and centrifugation.
[0025] In S1, the drying method for the fluoride-containing wastewater is specifically vacuum drying.
[0026] In S1, the particle size of the fluorinated organic compound and polymer powder is 10-120 mesh.
[0027] In S2, the inert organic solvent is at least one of mineral oil, tetrahydrofuran, diethyl ether, toluene, and xylene.
[0028] In step S2, the sodium metal is chopped and added to an inert organic solvent, and stirred to form a sodium metal dispersion under high-speed shear force.
[0029] In S3, the molar ratio of the metallic sodium to the fluorine in the fluorine-containing organic matter and polymer micro powder is 1.5-3:1.
[0030] In S3, the decomposition reaction temperature is 0-40 ℃ and the reaction time is 5-10 h.
[0031] In step S3, after the decomposition reaction is completed, pure water is added dropwise to the reaction solution until no more bubbles are generated, in order to remove residual metallic sodium.
[0032] In S4, the products of the decomposition reaction are sequentially filtered, centrifuged, washed, and dried to obtain inorganic sodium fluoride and carbonaceous materials.
[0033] In this application, to avoid introducing impurities, unless otherwise specified, all water used is deionized water.
[0034] The fluoride-containing wastewater described in this application typically originates from the flocculated filtrate following the emulsion polymerization of perfluoroether elastomers. It mainly contains: non-aggregated and non-precipitated colloidal monomers, colloidal oligomers, HFPO-TA and HFPO-DA surfactants, free F ions, and water. Typical composition of this wastewater, as determined by testing, is as follows: total fluoride content approximately 280-500 mg / L, including 40-200 mg / L of surfactants, 20-100 mg / L of free F ions, and a small amount of unpolymerized fluoride oligomers and residual monomers; solid content is 0.3%~0.5%. The composition of different batches of wastewater may vary within the above range, but the methods described in this application are applicable to all batches.
[0035] The amount of sodium metal added in this application takes into account the 1.0% to 3.5% moisture content remaining in the powder after drying, ensuring sufficient reaction with fluorine-containing organic compounds and avoiding a decrease in decomposition rate due to moisture consuming sodium metal.
[0036] Example 1
[0037] A method for decomposing organic fluorine compounds in fluoride-containing wastewater includes S1, concentrating and drying the fluoride-containing wastewater (composition as described above) to obtain fluoride-containing organic compounds and polymer micropowder. Specifically, the concentration and drying process involves separating the flocculated filtrate after preparing the perfluoroether elastomer emulsion from the fluoride-containing wastewater filtrate. The flocculated fluoride-containing wastewater filtrate (solid content approximately 0.3%) is then concentrated using an activated carbon felt adsorption bed (30 mm in diameter, 0.5 m in length) to obtain a concentrate with a solid content of 5.6%. The concentrate is then centrifuged using a hydrophilic PTFE coated cloth (10 mesh) (tubular centrifuge, Shanghai Daibao Machinery Equipment Co., Ltd.; speed 17500 rpm). The obtained filter cake is then vacuum dried, pulverized, and sieved to obtain micropowder with a particle size of 30-50 mesh.
[0038] S2. Based on the molar amount of fluorine in the fluorine-containing organic matter and polymer powder and the 3.0% moisture content remaining after drying the powder, the amount of sodium metal to be added was determined to be 1.6 g. 1.6 g of sodium metal was diced and dispersed in 20 ml of inert tetrahydrofuran and stirred to form a sodium metal dispersion. S3. Weigh 3 g of fluorine-containing organic matter and polymer powder and mix with sodium metal dispersion for decomposition reaction. The decomposition reaction is carried out at room temperature of 25 ℃ for 8 h. After 8 h of reaction, add pure water dropwise to the reaction solution until no bubbles are generated, so as to completely react the remaining sodium metal in the dispersion.
[0039] S4. After filtering, centrifuging, washing and drying the product of the decomposition reaction in S3, inorganic sodium fluoride and carbonaceous material are obtained. The specific process is as follows: the reaction product is filtered to obtain filtrate and filter cake, the filter cake being carbonaceous material; the filtrate is centrifuged at 4000 rpm for 10 min to obtain precipitate; the precipitate is washed three times successively with deionized water and ethanol; the washed precipitate is vacuum dried at 60 ℃ for 4 h to obtain sodium fluoride product.
[0040] Example 2
[0041] A method for decomposing organic fluorine compounds in fluoride-containing wastewater uses fluoride-containing wastewater with the same composition as described above, including S1, concentrating and drying the fluoride-containing wastewater to obtain fluoride-containing organic compounds and polymer micro powders. The specific concentration and drying processes are the same as in Example 1.
[0042] S2. Based on the molar amount of fluorine in the fluorine-containing organic compound and polymer powder, and the 3.0% moisture content remaining after drying the powder, the amount of sodium metal to be added is determined to be 2 g. 2 g of sodium metal is diced and dispersed in 25 ml of inert toluene and stirred to form a sodium metal dispersion. S3. Weigh 3 g of fluorine-containing organic matter and polymer powder and mix with sodium metal dispersion for decomposition reaction. The decomposition reaction is carried out at room temperature of 25 ℃ for 8 h. After 8 h of reaction, add pure water dropwise to the reaction solution until no bubbles are generated, so as to completely react the remaining sodium metal in the dispersion.
[0043] S4. After filtering, centrifuging, washing and drying the products of the decomposition reaction in S3, inorganic sodium fluoride and carbonaceous materials are obtained. The specific process is the same as in Example 1.
[0044] Example 3
[0045] A method for decomposing organic fluorine compounds in fluoride-containing wastewater uses fluoride-containing wastewater with the same composition as described above, including S1, concentrating and drying the fluoride-containing wastewater to obtain fluoride-containing organic compounds and polymer micro powders. The specific concentration and drying processes are the same as in Example 1.
[0046] S2. Based on the molar amount of fluorine in the fluorine-containing organic compound and polymer powder, and the 3.0% moisture content remaining after drying the powder, the amount of sodium metal to be added is determined to be 3 g. 3 g of sodium metal is diced and dispersed in 30 ml of inert xylene and stirred to form a sodium metal dispersion. S3. Weigh 3 g of fluorine-containing organic matter and polymer powder and mix with sodium metal dispersion for decomposition reaction. The decomposition reaction is carried out at room temperature of 25 ℃ for 8 h. After 8 h of reaction, add pure water dropwise to the reaction solution until no bubbles are generated, so as to completely react the remaining sodium metal in the dispersion.
[0047] S4. After filtering, centrifuging, washing and drying the products of the decomposition reaction in S3, inorganic sodium fluoride and carbonaceous materials are obtained. The specific process is the same as in Example 1.
[0048] Example 4
[0049] A method for decomposing organic fluorine compounds in fluoride-containing wastewater uses fluoride-containing wastewater with the same composition as described above, including S1. The fluoride-containing wastewater is concentrated and dried to obtain fluoride-containing organic compounds and polymer micro powders. The specific concentration and drying processes are the same as in Example 1, except that the particle size is 80-120 mesh.
[0050] S2. Based on the molar amount of fluorine in the fluorine-containing organic compound and polymer powder, and the 3.0% moisture content remaining after drying the powder, the amount of sodium metal to be added was determined to be 1.6 g. 1.6 g of sodium metal was diced and dispersed in 20 ml of inert xylene and stirred to form a sodium metal dispersion. S3. Weigh 3 g of fluorine-containing organic matter and polymer powder and mix with sodium metal dispersion for decomposition reaction. The decomposition reaction is carried out at room temperature of 25 ℃ for 8 h. After 8 h of reaction, add pure water dropwise to the reaction solution until no bubbles are generated, so as to completely react the remaining sodium metal in the dispersion.
[0051] S4. After filtering, centrifuging, washing and drying the products of the decomposition reaction in S3, inorganic sodium fluoride and carbonaceous materials are obtained. The specific process is the same as in Example 1.
[0052] Example 5
[0053] A method for decomposing organic fluorine compounds in fluoride-containing wastewater uses fluoride-containing wastewater with the same composition as described above, including S1, concentrating and drying the fluoride-containing wastewater to obtain fluoride-containing organic compounds and polymer micro powders. The specific concentration and drying processes are the same as in Example 1.
[0054] S2. Based on the molar amount of fluorine in the fluorine-containing organic compound and polymer powder, and the 0.6% moisture content remaining after drying the powder, the amount of sodium metal to be added was determined to be 1.6 g. The 1.6 g of sodium metal was diced and dispersed in 20 ml of inert xylene and stirred to form a sodium metal dispersion. S3. Weigh 3 g of fluorine-containing organic matter and polymer powder and mix with sodium metal dispersion for decomposition reaction. The decomposition reaction is carried out at room temperature of 25 ℃ for 8 h. After 8 h of reaction, add pure water dropwise to the reaction solution until no bubbles are generated, so as to completely react the remaining sodium metal in the dispersion.
[0055] S4. After filtering, centrifuging, washing and drying the products of the decomposition reaction in S3, inorganic sodium fluoride and carbonaceous materials are obtained. The specific process is the same as in Example 1.
[0056] The concentration of fluorinated organic compounds in the reaction solution before and after the reaction was detected by LC-MS, and the decomposition rate was calculated.
[0057] Decomposition rate is defined as:
[0058] In the formula, C0 and C are the initial and post-decomposition concentrations of fluorinated organic compounds, respectively.
[0059] Table 1 shows the decomposition rate and the weight of the inorganic product sodium fluoride under different embodiments of this application.
[0060] Example 1 Example 2 Example 3 Example 4 Example 5 Decomposition rate (%) 97.2 98.3 99.5 98.1 98.3 Nave (g) 3.1 3.2 3.2 3.2 3.2 A comparison of Examples 1, 2, and 3 shows that appropriately increasing the amount of metallic sodium is beneficial for the more thorough decomposition of fluorine-containing organic compounds, thereby improving the decomposition rate. However, beyond a certain proportion, the yield of sodium fluoride no longer increases significantly, indicating that there is an optimal ratio range.
[0061] A comparison between Example 4 and Example 1 shows that when the particle size of the micro powder is reduced, the metallic sodium comes into full contact with the micro powder particles, thereby improving the decomposition rate of fluorine-containing organic compounds.
[0062] A comparison between Example 5 and Example 1 shows that when the moisture content in the micronized powder is high, the moisture consumes some of the metallic sodium, reducing its effective contact with fluorine-containing organic compounds and leading to a decrease in the decomposition rate. In Example 5, by reducing the moisture content to 0.6%, the side reaction loss of metallic sodium was reduced, and the decomposition rate increased from 97.2% to 98.3%.
[0063] In this specification, similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the descriptions of the embodiments described later are relatively simple, and relevant parts can be referred to the descriptions of the foregoing embodiments.
[0064] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A method for decomposing organofluorine compounds in fluoride-containing wastewater, characterized in that: S1. Fluorine-containing organic compounds and polymer powders are obtained by concentrating and drying fluorine-containing wastewater. S2. Disperse metallic sodium in an inert organic solvent to form a metallic sodium dispersion; S3. The fluorinated organic compound and polymer powder are mixed with the sodium metal dispersion to carry out a decomposition reaction; S4. After separating the products of the decomposition reaction in S3, inorganic sodium fluoride and carbonaceous materials are obtained.
2. The method for decomposing organofluorine compounds in fluoride-containing wastewater according to claim 1, characterized in that: In S1, the concentration includes concentration by means of adsorption and centrifugation.
3. The method for decomposing organofluorine compounds in fluoride-containing wastewater according to claim 2, characterized in that: In S1, the drying method for the fluoride-containing wastewater is specifically vacuum drying.
4. The method for decomposing organofluorine compounds in fluoride-containing wastewater according to claim 1, characterized in that: In S1, the particle size of the fluorinated organic compound and polymer powder is 10-120 mesh.
5. The method for decomposing organofluorine compounds in fluoride-containing wastewater according to claim 1, characterized in that: In S2, the inert organic solvent is at least one of mineral oil, tetrahydrofuran, diethyl ether, toluene, and xylene.
6. The method for decomposing organofluorine compounds in fluoride-containing wastewater according to claim 1, characterized in that: In step S2, the sodium metal is chopped and added to an inert organic solvent, and stirred to form a sodium metal dispersion under high-speed shear force.
7. The method for decomposing organofluorine compounds in fluoride-containing wastewater according to claim 1, characterized in that: In S3, the molar ratio of the metallic sodium to the fluorine in the fluorine-containing organic matter and polymer micro powder is 1.5-3:
1.
8. The method for decomposing organofluorine compounds in fluoride-containing wastewater according to claim 1, characterized in that: In S3, the decomposition reaction temperature is 0-40 ℃ and the reaction time is 5-10 h.
9. The method for decomposing organofluorine compounds in fluoride-containing wastewater according to claim 1, characterized in that: In step S3, after the decomposition reaction is completed, pure water is added dropwise to the reaction solution until no more bubbles are generated, in order to remove residual metallic sodium.
10. The method for decomposing organofluorine compounds in fluoride-containing wastewater according to claim 1, characterized in that: In S4, the products of the decomposition reaction are sequentially filtered, centrifuged, washed, and dried to obtain inorganic sodium fluoride and carbonaceous materials.