A method for treating industrial wastewater containing 5-azoniumspiro[4.4]nonane tetrafluoroborate

Abstract

A kind of industrial wastewater treatment method containing 5-azepinium spiro [4.4] nonane tetrafluoroborate, belong to chemical wastewater treatment technical field, including the following steps: A, to industrial wastewater is added coagulant, then electrolysis, after filtering precipitate, obtain primary filtrate;B, to primary filtrate is added flocculating agent, after filtering precipitate, obtain secondary filtrate;C, adjust the PH value of secondary filtrate to 10~12, after adding catalyst, heating, again adjust the PH value of heated secondary filtrate to 6~8;D, the secondary filtrate of step C is added acid solution is biologically treated, obtain tertiary filtrate;E, after reverse osmosis treatment, tertiary filtrate can be discharged or recycled.The industrial wastewater treatment method of the application step design is reasonable, harmful substances in industrial wastewater are effectively treated using catalyst of specific component, so that the finally discharged industrial wastewater meets national standard.

Description

Technical Field

[0001] This invention belongs to the field of chemical wastewater treatment technology, specifically relating to a method for treating industrial wastewater containing 5-aza-onium-spiro[4.4]nonane tetrafluoroborate. Background Technology

[0002] 5-Nitrogen spiro[4.4]nonane tetrafluoroborate (SBP-BF4), also known as spirocyclic quaternary ammonium salt of tetrafluoroborate, is a new type of ionic liquid salt for supercapacitors. Due to its advantages such as high conductivity, wide electrochemical window, good electrochemical stability, wide operating temperature range, and high solubility in organic solvents, it has attracted widespread attention in recent years.

[0003] However, due to the toxicity of 5-azaspiro[4.4]nonanetetrafluoroborate, which is also toxic to aquatic organisms, strict wastewater treatment is required for industrial wastewater containing 5-azaspiro[4.4]nonanetetrafluoroborate. Traditional wastewater treatment methods for quaternary ammonium salts typically involve acidification followed by biological treatment. However, due to the stable structure of spirocyclic quaternary ammonium salts, 5-azaspiro[4.4]nonanetetrafluoroborate is difficult to degrade, thus making biological treatment impossible. The CN content in spirocyclic quaternary ammonium salts... + Unlike ordinary CN bonds, CN bonds are destroyed by methods that break the CN bond. + The key effect is poor, CN + The bond breakage was incomplete. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for treating industrial wastewater containing 5-aza-onium-spiro[4.4]nonane tetrafluoroborate. The industrial wastewater treatment method of this invention has a rationally designed procedure and uses a catalyst with specific components to effectively treat harmful substances in the industrial wastewater, ensuring that the final discharged industrial wastewater meets national standards.

[0005] The specific technical solution adopted in this invention is as follows:

[0006] A method for treating industrial wastewater containing 5-aza-onium-spiro[4.4]nonane tetrafluoroborate includes the following steps:

[0007] A. After adding coagulant to industrial wastewater and heating it, the industrial wastewater is then electrolyzed. Once no more precipitates are formed, the precipitates are filtered out to obtain primary filtrate.

[0008] B. Add flocculant to the primary filtrate. After no more precipitates are formed, filter and separate the precipitates to obtain the secondary filtrate.

[0009] C. Add an alkaline solution to the secondary filtrate to adjust the pH to 10-12, then add a catalyst and heat it. Add an acid solution to the heated secondary filtrate to adjust the pH to 6-8.

[0010] D. The secondary filtrate containing acid solution from step C is subjected to biological treatment to obtain the tertiary filtrate.

[0011] E. Connect the tertiary filtrate to the reverse osmosis system. After reverse osmosis treatment, the tertiary filtrate can be discharged or recycled.

[0012] Furthermore, the coagulant mentioned in step A is ferric sulfate, and the molar ratio of the amount of coagulant added to the fluoride ions in the wastewater is 1:3 to 4.

[0013] The molar ratio of ferric sulfate added to fluoride ions in the wastewater is 1:3-4. Adding ferric sulfate at this ratio allows the ferric ions in the ferric sulfate to fully react with the borofluoride ions in the water, generating FeF6. 3﹣ .

[0014] Furthermore, the heating temperature in step A is 50–60°C, and the heating time is 30–60 min.

[0015] Heating at 50–60°C can promote the forward reaction between iron ions and borofluoride ions.

[0016] Furthermore, during the electrolytic treatment described in step A, an inert conductive material is used as the cathode and lead is used as the anode. The inert conductive material is one of graphite, glassy carbon, and titanium.

[0017] Furthermore, the flocculant mentioned in step B is calcium hydroxide, and the molar ratio of the amount of flocculant added to the fluoride ions in the wastewater is 2 to 3:4.

[0018] The molar ratio of calcium hydroxide to fluoride ions in the wastewater should be 2–3:4. Excessive addition of calcium hydroxide can increase the concentration of Ca2+ ions in the wastewater. + With F - The reaction is more thorough, promoting the formation of CaF2 and improving the removal rate of fluoride ions.

[0019] Furthermore, the alkaline solution in step C is sodium hydroxide, and the acid solution is hydrochloric acid.

[0020] Furthermore, the catalyst in step C comprises, by weight, 3 to 5 parts of a methanol solution of sodium methoxide, 1 to 2 parts of bentonite, and 1 to 2 parts of ethyl acetate, wherein the concentration of the methanol solution of sodium methoxide is 10% to 20%.

[0021] Furthermore, the amount of catalyst added in step C is 0.3 to 0.5% of the mass of the industrial wastewater.

[0022] Furthermore, the heating temperature in step C is 40–50°C, and the heating time is 2–4 hours.

[0023] Using a specific ratio of sodium methoxide in methanol, bentonite, and ethyl acetate as catalysts, CN... + The shared electrons of the covalent bond are attracted by the active metal ions in bentonite, catalyzing the ring-opening reaction of 5-aza-onium spiro[4.4]nonane tetrafluoroborate under alkaline and heated conditions, thus breaking the CN bond more thoroughly. + The bonds are broken, disrupting the spiral ring structure, allowing harmful components in industrial wastewater to be degraded through biological treatment.

[0024] Furthermore, the biological treatment described in step D includes the following steps:

[0025] D1. Introduce the secondary filtrate with added acid solution from step C into the anaerobic biological treatment tank for anaerobic reaction, controlling the temperature at 25-35℃ and the reaction time at 24-48h.

[0026] D2. The secondary filtrate after anaerobic reaction is introduced into the aerobic biological treatment tank for aerobic reaction. The temperature is controlled at 25-35℃, the reaction time is 24-48h, and the dissolved oxygen is 2-4mg / L.

[0027] D3. The secondary filtrate that has undergone aerobic reaction is connected to the mud-water separation tank, and the resulting clear liquid is the tertiary filtrate.

[0028] Anaerobic and aerobic bacteria thrive at pH 6–8 and 25–35°C. Too high or too low pH affects bacterial activity, while low temperatures slow bacterial growth and high temperatures cause bacteria to age prematurely.

[0029] The beneficial effects of this invention are:

[0030] 1. In this invention, by rationally designing a treatment method for industrial wastewater containing 5-aza-onium-spiro[4.4]nonane tetrafluoroborate, a catalyst with specific components is used to effectively treat the harmful substances in the industrial wastewater, so that the final discharged industrial wastewater meets national standards. At the same time, each step in this treatment method is a conventional operation, the treatment steps are simple, and it is easy to promote and apply.

[0031] 2. In this invention, a specific ratio of sodium methoxide in methanol, bentonite, and ethyl acetate is used as a catalyst. Under the action of the sodium methoxide in methanol and ethyl acetate, CN... + The shared electrons of the covalent bond are attracted by the active metal ions in bentonite, catalyzing the ring-opening reaction of 5-aza-onium spiro[4.4]nonane tetrafluoroborate under alkaline and heated conditions, thus breaking the CN bond more thoroughly.+ The bonds are broken, disrupting the spiral ring structure, allowing harmful components in industrial wastewater to be degraded through biological treatment.

[0032] 3. In this invention, by using ferric sulfate and calcium hydroxide in combination, and with the optimization of process parameters such as pH and temperature, the fluoride removal rate in industrial wastewater reaches over 98%. Ferric sulfate first reacts with borate ions in the industrial wastewater to generate FeF6. 3﹣ Then FeF6 3— It reacts with calcium hydroxide to first form a large amount of flocculent ferric hydroxide precipitate, while simultaneously releasing reactive ferric hydroxide (F). ﹣ Ca 2+ With F ﹣ CaF2 precipitate is generated. Due to the coagulation and adsorption of ferric hydroxide, the precipitation performance of CaF2 is effectively improved, allowing fluoride ions to be removed more thoroughly. In addition, traditional methods for decomposing borate ions are usually carried out at 80-90°C, while the method in this invention is carried out at 50-60°C, saving energy and reducing wastewater treatment costs.

[0033] 4. In this invention, due to the addition of ferric sulfate, sulfate ions are introduced into the industrial wastewater. Therefore, lead is used as the anode and an inert conductive material is used as the cathode to electrolyze the industrial wastewater, so that sulfate ions are converted into lead sulfate precipitate, thus avoiding secondary pollution.

[0034] 5. In this invention, the industrial wastewater is first subjected to an anaerobic reaction, and then to an aerobic reaction. By utilizing the anaerobic bacteria in the anaerobic biological treatment tank, the COD of the wastewater can be significantly reduced. At the same time, the toxicity of toxic and harmful organic amines in the wastewater is reduced, and the biodegradability of recalcitrant substances is improved, making them into substances that can be utilized by aerobic microorganisms. There is no need to increase the BOD / COD, which simplifies the treatment steps and reduces costs.

[0035] 6. In this invention, reverse osmosis treatment is set up to treat industrial wastewater at a deeper level, so that the reverse osmosis industrial wastewater not only meets the national industrial wastewater discharge standards, but can also be recycled and reused, thereby reducing industrial production costs. Detailed Implementation

[0036] During normal production, the concentration of 5-aza-onium-spiro[4.4]nonane tetrafluoroborate in the industrial wastewater generated by our company is between 2% and 3%. I. Specific Implementation Methods

[0038] Example 1

[0039] A. Input 1000 kg of industrial wastewater into the receiving tank, add ferric sulfate and heat at 55°C for 40 min. The molar ratio of ferric sulfate added to fluoride ions in the wastewater is 1:3.5. Then, use lead as the anode and graphite as the cathode to electrolyze the industrial wastewater. After no more precipitates are generated, filter to separate the precipitates and obtain the first-stage filtrate.

[0040] B. Input the primary filtrate into the reaction tank, and then add calcium hydroxide in batches. The molar ratio of the amount of calcium hydroxide added to the fluoride ions in the wastewater is 2.5:4. After no more precipitates are formed, filter and separate the precipitates to obtain the secondary filtrate.

[0041] C. Add sodium hydroxide to the secondary filtrate to adjust the pH to 11, then add 2 kg of 15% sodium methoxide methanol solution, 1 kg of bentonite, and 1 kg of ethyl acetate. Heat to 45°C for 3 hours. Add hydrochloric acid to the heated secondary filtrate to adjust the pH to 7.

[0042] D1. The secondary filtrate containing hydrochloric acid from step C is introduced into the anaerobic biological treatment tank for anaerobic reaction. The temperature is controlled at 30℃ and the reaction time is 36h.

[0043] D2. The secondary filtrate after anaerobic reaction is introduced into the aerobic biological treatment tank for aerobic reaction. The temperature is controlled at 30℃, the reaction time is 36h, and the dissolved oxygen is 3mg / L.

[0044] D3. The secondary filtrate after aerobic reaction is fed into the mud-water separation tank, and the resulting clear liquid is the tertiary filtrate.

[0045] E. Connect the tertiary filtrate to the reverse osmosis system. After reverse osmosis treatment, the tertiary filtrate can be discharged or recycled.

[0046] Example 2

[0047] A. Input 950 kg of industrial wastewater into the receiving tank, add ferric sulfate and heat at 50°C for 60 min. The molar ratio of ferric sulfate added to fluoride ions in the wastewater is 1:3. Then, using lead as the anode and titanium as the cathode, electrolyze the industrial wastewater. After no more precipitates are generated, filter and separate the precipitates to obtain the first-stage filtrate.

[0048] B. Input the primary filtrate into the reaction tank, and then add calcium hydroxide in batches. The molar ratio of the amount of calcium hydroxide added to the fluoride ions in the wastewater is 1:2. After no more precipitates are formed, filter and separate the precipitates to obtain the secondary filtrate.

[0049] C. Add sodium hydroxide to the secondary filtrate to adjust the pH to 10, then add 1.7 kg of 20% sodium methoxide methanol solution, 0.6 kg of bentonite, and 0.6 kg of ethyl acetate. Heat to 40°C for 4 hours. Add hydrochloric acid to the heated secondary filtrate to adjust the pH to 6.

[0050] D1. The secondary filtrate containing hydrochloric acid from step C is introduced into the anaerobic biological treatment tank for anaerobic reaction. The temperature is controlled at 35℃ and the reaction time is 24h.

[0051] D2. The secondary filtrate after anaerobic reaction is introduced into the aerobic biological treatment tank for aerobic reaction. The temperature is controlled at 35℃, the reaction time is 24h, and the dissolved oxygen is 2mg / L.

[0052] D3. The secondary filtrate after aerobic reaction is fed into the mud-water separation tank, and the resulting clear liquid is the tertiary filtrate.

[0053] E. Connect the tertiary filtrate to the reverse osmosis system. After reverse osmosis treatment, the tertiary filtrate can be discharged or recycled.

[0054] Example 3

[0055] A. Input 980 kg of industrial wastewater into the receiving tank, add ferric sulfate and heat at 60°C for 30 min. The molar ratio of ferric sulfate added to fluoride ions in the wastewater is 1:4. Then, using lead as the anode and glassy carbon as the cathode, electrolyze the industrial wastewater. After no more precipitates are generated, filter and separate the precipitates to obtain the first-stage filtrate.

[0056] B. Input the primary filtrate into the reaction tank, and then add calcium hydroxide in batches. The molar ratio of the amount of calcium hydroxide added to the fluoride ions in the wastewater is 3:4. After no more precipitates are formed, filter and separate the precipitates to obtain the secondary filtrate.

[0057] C. Add sodium hydroxide to the secondary filtrate to adjust the pH to 12, then add 2 kg of 10% sodium methoxide methanol solution, 1.5 kg of bentonite, and 1.5 kg of ethyl acetate. Heat to 50°C for 2 hours. Add hydrochloric acid to the heated secondary filtrate to adjust the pH to 8.

[0058] D1. The secondary filtrate containing hydrochloric acid from step C is introduced into the anaerobic biological treatment tank for anaerobic reaction. The temperature is controlled at 25℃ and the reaction time is 48h.

[0059] D2. The secondary filtrate after anaerobic reaction is introduced into the aerobic biological treatment tank for aerobic reaction. The temperature is controlled at 25℃, the reaction time is 48h, and the dissolved oxygen is 4mg / L.

[0060] D3. The secondary filtrate after aerobic reaction is fed into the mud-water separation tank, and the resulting clear liquid is the tertiary filtrate.

[0061] E. Connect the tertiary filtrate to the reverse osmosis system. After reverse osmosis treatment, the tertiary filtrate can be discharged or recycled.

[0062] Example 4

[0063] A. Input 920 kg of industrial wastewater into the receiving tank, add ferric sulfate and heat at 52°C for 50 min. The molar ratio of ferric sulfate added to fluoride ions in the wastewater is 1:3.2. Then, using lead as the anode and graphite as the cathode, electrolyze the industrial wastewater. After no more precipitates are generated, filter and separate the precipitates to obtain the first-stage filtrate.

[0064] B. Input the primary filtrate into the reaction tank, and then add calcium hydroxide in batches. The molar ratio of the amount of calcium hydroxide added to the fluoride ions in the wastewater is 2.3:4. After no more precipitates are formed, filter and separate the precipitates to obtain the secondary filtrate.

[0065] C. Add sodium hydroxide to the secondary filtrate to adjust the pH to 11, then add 1 kg of 12% sodium methoxide methanol solution, 1 kg of bentonite, and 1 kg of ethyl acetate. Heat to 42°C for 2.5 h. Add hydrochloric acid to the heated secondary filtrate to adjust the pH to 7.

[0066] D1. The secondary filtrate containing hydrochloric acid from step C is introduced into the anaerobic biological treatment tank for anaerobic reaction. The temperature is controlled at 32℃ and the reaction time is 30h.

[0067] D2. The secondary filtrate after anaerobic reaction is introduced into the aerobic biological treatment tank for aerobic reaction. The temperature is controlled at 28℃, the reaction time is 40h, and the dissolved oxygen is 2.5mg / L.

[0068] D3. The secondary filtrate after aerobic reaction is fed into the mud-water separation tank, and the resulting clear liquid is the tertiary filtrate.

[0069] E. Connect the tertiary filtrate to the reverse osmosis system. After reverse osmosis treatment, the tertiary filtrate can be discharged or recycled.

[0070] Example 5

[0071] A. Input 960 kg of industrial wastewater into the receiving tank, add ferric sulfate and heat at 57°C for 35 min. The molar ratio of ferric sulfate added to fluoride ions in the wastewater is 1:3.8. Then, using lead as the anode and graphite as the cathode, electrolyze the industrial wastewater. After no more precipitates are generated, filter and separate the precipitates to obtain the first-stage filtrate.

[0072] B. Input the primary filtrate into the reaction tank, and then add calcium hydroxide in batches. The molar ratio of the amount of calcium hydroxide added to the fluoride ions in the wastewater is 2.8:4. After no more precipitates are formed, filter and separate the precipitates to obtain the secondary filtrate.

[0073] C. Add sodium hydroxide to the secondary filtrate to adjust the pH to 11, then add 2.4 kg of 18% sodium methoxide methanol solution, 1.44 kg of bentonite, and 0.48 kg of ethyl acetate. Heat to 48°C for 3.5 h. Add hydrochloric acid to the heated secondary filtrate to adjust the pH to 7.

[0074] D1. The secondary filtrate containing hydrochloric acid from step C is introduced into the anaerobic biological treatment tank for anaerobic reaction. The temperature is controlled at 28℃ and the reaction time is 40h.

[0075] D2. The secondary filtrate after anaerobic reaction is introduced into the aerobic biological treatment tank for aerobic reaction. The temperature is controlled at 32℃, the reaction time is 30h, and the dissolved oxygen is 3.5mg / L.

[0076] D3. The secondary filtrate after aerobic reaction is fed into the mud-water separation tank, and the resulting clear liquid is the tertiary filtrate.

[0077] E. Connect the tertiary filtrate to the reverse osmosis system. After reverse osmosis treatment, the tertiary filtrate can be discharged or recycled.

[0078] Comparative Example 1

[0079] The only difference between Comparative Example 1 and Example 1 is that ferric sulfate is not added in step A of Comparative Example 1.

[0080] Comparative Example 2

[0081] The only difference between Comparative Example 2 and Example 1 is that the catalyst in Comparative Example 2, by weight, includes 2.67 kg of a 15% sodium methoxide methanol solution and 1.33 kg of bentonite.

[0082] Comparative Example 3

[0083] The only difference between Comparative Example 3 and Example 1 is that the catalyst in Comparative Example 3, by weight, includes 2.67 kg of a 15% sodium methoxide methanol solution and 1.33 kg of ethyl acetate.

[0084] Comparative Example 4

[0085] The only difference between Comparative Example 4 and Example 1 is that the catalyst in step C of Comparative Example 4 is 4 kg of a 15% sodium methoxide methanol solution.

[0086] II. Performance Testing

[0087] 100g of each of the treated industrial wastewater obtained in Examples 1 to 5 and Comparative Examples 1 to 4 was taken as a sample, and the concentration of each ion and the COD content in the sample were tested. The test results are shown in Table 1.

[0088] Table 1

[0089]

[0090] As shown in Table 1, compared with Example 1, no ferric sulfate was added in Comparative Example 1. Therefore, the borofluoride ions in 5-aza-spiro[4.4]nonane tetrafluoroborate were not completely decomposed, reducing the removal rate of fluoride and boron ions. Compared with Comparative Examples 2-4, the catalyst added in Example 1 included a methanol solution of sodium methoxide, bentonite, and ethyl acetate. The methanol solution of sodium methoxide, bentonite, and ethyl acetate in the catalyst components of Example 1 produced a synergistic reaction. Under the action of the methanol solution of sodium methoxide and ethyl acetate, CN + The shared electrons of the covalent bonds are attracted by the active metal ions in bentonite, catalyzing the ring-opening reaction of 5-aza-onium spiro[4.4]nonane tetrafluoroborate under alkaline and heated conditions, thus destroying its spirocyclic structure. This allows harmful components in industrial wastewater to be degraded through biological treatment, significantly improving the removal rate of ammonia ions and reducing the COD value of industrial wastewater. Industrial wastewater treated using the method of this invention has a fluoride ion content ≤0.48 mg / L, a boron ion content ≤1.57 mg / L, a nitrogen ion content ≤2.12 mg / L, a sulfate ion content ≤0.03 mg / L, and a COD ≤78 mg / L, meeting the national industrial wastewater discharge standards and also allowing for recycling and reuse.

Claims

1. A method for treating industrial wastewater containing 5-aza-onium spiro[4,4]nonane tetrafluoroborate, characterized in that, Includes the following steps: A. After adding coagulant to industrial wastewater and heating it, the industrial wastewater is then electrolyzed. Once no more precipitates are formed, the precipitates are filtered out to obtain primary filtrate. The coagulant mentioned in step A is ferric sulfate, the molar ratio of the amount of coagulant added to the fluoride ions in the wastewater is 1:3~4, the heating temperature is 50~60℃, the heating time is 30~60min, and during the electrolytic treatment, an inert conductive material is used as the cathode and lead is used as the anode. The inert conductive material is one of graphite, glassy carbon, and titanium. B. Add flocculant to the primary filtrate. After no more precipitates are formed, filter and separate the precipitates to obtain the secondary filtrate. The flocculant mentioned in step B is calcium hydroxide, and the molar ratio of the amount of flocculant added to the fluoride ions in the wastewater is 2~3:

4. C. Add an alkaline solution to the secondary filtrate to adjust the pH to 10-12, then add a catalyst and heat it. Add an acid solution to the heated secondary filtrate to adjust the pH to 6-8. The catalyst mentioned in step C, by weight, comprises 3-5 parts of a methanol solution of sodium methoxide, 1-3 parts of bentonite, and 1-3 parts of ethyl acetate. The concentration of the methanol solution of sodium methoxide is 10%-20%. The amount of catalyst added is 0.3-0.5% of the mass of industrial wastewater. The heating temperature is 40-50°C, and the heating time is 2-4 hours. D. The secondary filtrate containing acid solution from step C is subjected to biological treatment to obtain the tertiary filtrate. E. Connect the tertiary filtrate to the reverse osmosis system. After reverse osmosis treatment, the tertiary filtrate can be discharged or recycled.

2. The method for treating industrial wastewater containing 5-aza-onium-spiro[4.4]nonane tetrafluoroborate according to claim 1, characterized in that, The alkaline solution in step C is sodium hydroxide, and the acid solution is hydrochloric acid.

3. The method for treating industrial wastewater containing 5-aza-onium-spiro[4.4]nonane tetrafluoroborate according to claim 1, characterized in that, The biological treatment described in step D includes the following steps: D1. Introduce the secondary filtrate with added acid solution from step C into the anaerobic biological treatment tank for anaerobic reaction, controlling the temperature at 25~35℃ and the reaction time at 24~48h. D2. The secondary filtrate after anaerobic reaction is introduced into the aerobic biological treatment tank for aerobic reaction. The temperature is controlled at 25~35℃, the reaction time is 24~48h, and the dissolved oxygen is 2~4mg / L. D3. The secondary filtrate that has undergone aerobic reaction is connected to the mud-water separation tank, and the resulting clear liquid is the tertiary filtrate.

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