A wastewater treatment process
By combining electrochemical catalytic oxidation and ozone catalysis with biological contact oxidation, a thiol-rare earth hybrid MnO2 composite material was used to treat aniline wastewater, solving the problem of treating highly toxic aniline wastewater in existing technologies and achieving efficient and low-cost wastewater treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AOLI PETROCHEMICAL CO LTD DONG FANG BRANCH
- Filing Date
- 2025-05-12
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies are insufficient to effectively treat aniline wastewater that is highly toxic, highly saline, and highly chromatic. Biological treatment methods are difficult to meet standards, while physical and chemical methods are costly and prone to causing secondary pollution.
An electrochemical catalytic oxidation and ozone catalytic treatment combined with biological contact oxidation method was adopted. Thiol-rare earth hybrid MnO2 composite material was used as catalyst. Electrochemical catalytic oxidation and ozone catalysis were performed first, followed by biochemical treatment.
It significantly improves the degradation efficiency of aniline wastewater, reduces treatment costs, reduces secondary pollution, provides a better biochemical treatment environment, and enables wastewater to meet discharge standards.
Smart Images
Figure BDA0005396984590000071
Abstract
Description
Technical Field
[0001] This invention relates to the field of wastewater treatment technology, and in particular to a wastewater treatment process. Background Technology
[0002] Aniline is an important chemical raw material and intermediate, widely used in industries such as fuels, pharmaceuticals, explosives, pesticides, and military applications. It is an internationally recognized hazardous chemical. Aniline is a harmful substance that severely pollutes the environment and endangers human health. When such wastewater is discharged into water bodies, its toxicity not only hinders the growth of aquatic organisms but also seriously threatens human health. Therefore, my country's wastewater discharge standards have strict regulations for aniline-related substances. Aniline wastewater is characterized by high biological toxicity, high pollutant concentration, high salinity, and high color, and is a typical example of recalcitrant industrial wastewater.
[0003] Currently, the main methods for treating aniline wastewater include physical, chemical, biological, and combined methods. Physical methods, including adsorption, extraction, and membrane separation, utilize physical processes such as adsorption, extraction, and osmosis to separate aniline from the wastewater without altering its structure and properties. However, physical methods are prone to causing the transfer of new pollutants and are costly. Chemical methods, including photocatalytic oxidation, electrocatalytic oxidation, supercritical oxidation, and ultrasonic methods, all utilize strong oxidants or certain pathways to oxidize aniline, generating small molecules or inorganic substances to remove it. Chemical methods are relatively energy-intensive and not economically viable. While biological methods are an economical and effective purification method, the high toxicity of the wastewater limits their use, and achieving compliant discharge standards after treatment is difficult and inconsistent.
[0004] Therefore, it is of great significance to study an effective comprehensive method for treating aniline compound wastewater. Summary of the Invention
[0005] In view of this, the present invention proposes a wastewater treatment process.
[0006] The technical solution of this invention is implemented as follows:
[0007] A wastewater treatment process includes the following steps: first, electrochemical catalytic oxidation and ozone catalytic treatment are performed on aniline wastewater, and then biochemical treatment is performed by biological contact oxidation to bring the aniline wastewater up to the sewage discharge standard.
[0008] Both the electrochemical catalytic oxidation and ozone catalytic pretreatment stages incorporate thiol-rare earth hybrid MnO2 composite materials.
[0009] Furthermore, the preparation method of the thiol-rare earth hybrid MnO2 composite material includes:
[0010] (1) Add potassium permanganate and manganese sulfate to deionized water, add sulfuric acid dropwise to adjust the pH value to 2.5-3.5, transfer to a high pressure vessel for hydrothermal reaction, wash and dry to obtain MnO2 powder;
[0011] (2) Rare earth ions were added to water to prepare a solution. MnO2 was added under stirring conditions, ultrasonic stirring was performed, the solution was washed, and vacuum dried to obtain rare earth-doped MnO2 composite material.
[0012] (3) The rare earth-doped MnO2 composite material was dispersed in anhydrous ethanol, and maleic anhydride and p-toluenesulfonic acid were added to react and an intermediate product was obtained.
[0013] (4) The intermediate product was dispersed in anhydrous ethanol, and alkyl thiols and azobisisobutyronitrile were added to react. After centrifugation and washing, and vacuum drying, the thiol-rare earth hybrid MnO2 composite material was obtained.
[0014] Furthermore, in step (1), the molar ratio of potassium permanganate to manganese sulfate is 1:1-3; the solid-liquid ratio of potassium permanganate to deionized water is 1:30-40 g / mL; and the hydrothermal reaction is carried out at 120-140℃ for 12 h.
[0015] Furthermore, in step (2), the rare earth ions are nitrates containing lanthanum or cerium ions; the solid-liquid ratio of the rare earth ions to water is 1:60-80 g / mL; the amount of MnO2 added is 3-4 times the molar amount of the rare earth ions; the ultrasonic stirring is performed at 20-30 kHz and 25-35 °C for 4-6 hours.
[0016] Furthermore, in step (3), the solid-liquid ratio of the rare earth-doped MnO2 composite material to anhydrous ethanol is 1:20-40 g / mL; the mass ratio of the rare earth-doped MnO2 composite material to maleic anhydride and p-toluenesulfonic acid is 5-7:1:0.5-0.8; and the reaction is carried out at 80-90℃ for 4-6 h.
[0017] Furthermore, in step (4), the solid-liquid ratio of the intermediate product to anhydrous ethanol is 1:20-30 g / mL; the mass ratio of the alkyl thiol and azobisisobutyronitrile to the intermediate product is 1:0.1-0.3:3-5; the reaction temperature is 100-120℃ and the reaction time is 1-3 h.
[0018] Furthermore, the electrochemical catalytic oxidation specifically includes:
[0019] After homogenization in a pH adjustment tank, aniline wastewater is introduced into an electrochemical catalytic device. Thiol-rare earth hybrid MnO2 composite material is filled between three-dimensional electrodes for electrochemical catalytic oxidation.
[0020] Electrochemical catalytic oxidation can improve the ring-opening and breaking efficiency of recalcitrant and toxic organic compounds, and can remove recalcitrant COD from wastewater. cr It removes most of the ammonia nitrogen from the wastewater, greatly improving the wastewater's biodegradability. In addition, the treatment facility has a small footprint, a short process flow, low operating costs, does not require the addition of chemicals, produces less sludge, and the system's automated program can operate stably.
[0021] Furthermore, the pH adjustment tank adjusts the pH to 3-5; the electrochemical catalytic device is set with a current of 10-30 mA / cm². 2 Voltage 3-5V, temperature 25-35℃, time 1-2h.
[0022] Furthermore, the ozone catalysis specifically includes:
[0023] The wastewater after electrochemical catalytic oxidation is fed into an ozone catalytic oxidation device. The catalytic reactor is filled with a thiol-rare earth hybrid MnO2 composite material to carry out the reaction and obtain the treated wastewater.
[0024] Furthermore, the ozone catalytic oxidation device is set with an ozone concentration of 10-20 mg / L, a flow rate of 1-2 L / min, and a reaction time of 20-40 min.
[0025] Compared with the prior art, the beneficial effects of the present invention are:
[0026] 1. This invention applies a thiol-rare earth hybrid MnO2 composite material to the electrochemical catalytic oxidation process, which participates in the electron transfer reaction, generates more highly active oxygen species, provides more catalytic sites, and promotes the degradation of pollutants in aniline wastewater.
[0027] 2. This invention applies thiol-rare earth hybrid MnO2 composite material to the ozone catalytic treatment process, which not only provides more active sites to promote ozone decomposition and generate more -OH free radicals or other active species, thus improving the ozone degradation efficiency, but also increases the solubility of ozone in wastewater, resulting in a significant reduction in COD and a noticeable decolorization effect.
[0028] 3. The thiol-rare earth hybrid MnO2 composite material of the present invention has the characteristics of erosion resistance and high strength, which can reduce the resistance of wastewater. After the aniline wastewater pretreatment stage of the present invention, it can not only degrade pollutants, but also regulate water quality, provide a better reaction environment for subsequent biochemical treatment, reduce the burden of biochemical treatment, improve the degradation effect, and enable aniline wastewater to meet the discharge standards.
[0029] 4. Manganese dioxide, as a typical transition metal oxide, possesses strong redox capabilities and can catalyze the degradation of pollutants. It exhibits significant degradation effects on organic pollutants during electrochemical catalytic oxidation and ozone catalytic treatment. Rare earth elements enhance the catalytic performance and stability of manganese dioxide, improve its electron transfer capacity, and increase the degradation rate of the catalyst. Thiol groups can adsorb organic pollutants through hydrogen bonds, coordination bonds, and other forces, increasing adsorption sites and facilitating catalytic degradation. The thiol-rare earth hybrid MnO2 composite material of this invention exhibits good regenerability and high environmental friendliness. Under the synergistic effect of multiple forces, the thiol-rare earth hybrid MnO2 composite material demonstrates strong binding force and excellent selectivity for aniline wastewater, significantly improving removal efficiency. Detailed Implementation
[0030] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.
[0031] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.
[0032] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.
[0033] The alkyl thiols of the present invention are selected from any one of n-dodecyl thiols, n-tetradecyl thiols, n-hexadecyl thiols, and n-octadecyl thiols.
[0034] Example 1
[0035] A wastewater treatment process, the specific treatment steps are as follows:
[0036] (1) Electrochemical catalytic oxidation: After homogenization in a pH adjustment tank (pH = 3-5), the aniline wastewater is introduced into an electrochemical catalytic device. A thiol-rare earth hybrid MnO2 composite material is filled between the three-dimensional electrodes, and the current is set to 20 mA / cm². 2 Electrochemical catalytic oxidation was carried out at a voltage of 4V and a temperature of 30℃ for 1.5h.
[0037] (2) Ozone catalysis: The wastewater after electrochemical catalytic oxidation is fed into the ozone catalytic oxidation device, the ozone concentration is set to 15 mg / L, the flow rate is 1.5 L / min, the catalytic reactor is filled with thiol-rare earth hybrid MnO2 composite material, and the reaction is carried out for 30 min to obtain the treated wastewater.
[0038] (3) The treated wastewater is biochemically treated by biological contact oxidation.
[0039] The preparation methods of the thiol-rare earth hybrid MnO2 composite materials in (1) and (2) above include:
[0040] S1. Potassium permanganate and manganese sulfate with a molar ratio of 1:2 were added to deionized water. The solid-liquid ratio of potassium permanganate to deionized water was 1:35 g / mL. Sulfuric acid was added dropwise to adjust the pH value to 3.0±0.5. The mixture was then transferred to an autoclave and hydrothermally reacted at 130℃ for 12 h. The product was washed and dried to obtain MnO2 powder.
[0041] S2. Add nitrate containing lanthanum or cerium ions to water to prepare a solution. The solid-liquid ratio of lanthanum or cerium ions to water is 1:70 g / mL. Under stirring, add MnO2. The amount of MnO2 added is 3.5 times the molar amount of lanthanum or cerium ions. Stir ultrasonically at 25 kHz and 30 °C for 5 h. Filter, wash, and vacuum dry to obtain rare earth doped MnO2 composite material.
[0042] S3. According to the solid-liquid ratio of 1:30 g / mL, the rare earth-doped MnO2 composite material was dispersed in anhydrous ethanol, and maleic anhydride and p-toluenesulfonic acid were added. The mass ratio of the rare earth-doped MnO2 composite material to maleic anhydride and p-toluenesulfonic acid was 6:1:0.7. The reaction was carried out at 85℃ for 5 h to obtain the intermediate product.
[0043] S4. The intermediate product was dispersed in anhydrous ethanol at a solid-liquid ratio of 1:25 g / mL. Alkyl thiols and azobisisobutyronitrile were added, with a mass ratio of alkyl thiols and azobisisobutyronitrile to the intermediate product of 1:0.2:4. The mixture was reacted at 110 °C for 2 h, centrifuged, washed, and vacuum dried to obtain the thiol-rare earth hybrid MnO2 composite material.
[0044] Example 2
[0045] A wastewater treatment process, the specific treatment steps are as follows:
[0046] (1) Electrochemical catalytic oxidation: After homogenization in a pH adjustment tank (pH = 3-5), the aniline wastewater is introduced into an electrochemical catalytic device. A thiol-rare earth hybrid MnO2 composite material is filled between the three-dimensional electrodes, and the current is set to 10 mA / cm. 2 Electrochemical catalytic oxidation was carried out for 1 hour at a voltage of 3V and a temperature of 25℃.
[0047] (2) Ozone catalysis: The wastewater after electrochemical catalytic oxidation is fed into the ozone catalytic oxidation device. The ozone concentration is set to 10 mg / L and the flow rate is 1 L / min. The catalytic reactor is filled with thiol-rare earth hybrid MnO2 composite material and the reaction is carried out for 20 min to obtain the treated wastewater.
[0048] (3) The treated wastewater is biochemically treated by biological contact oxidation.
[0049] The preparation methods of the thiol-rare earth hybrid MnO2 composite materials in (1) and (2) above include:
[0050] S1. Add potassium permanganate and manganese sulfate in a molar ratio of 1:1 to deionized water. The solid-liquid ratio of potassium permanganate to deionized water is 1:30 g / mL. Add sulfuric acid dropwise to adjust the pH value to 3.0±0.5. Transfer to a high-pressure reactor and hydrothermally react at 120℃ for 12 h. Wash and dry the product to obtain MnO2 powder.
[0051] S2. Add nitrate containing lanthanum or cerium ions to water to prepare a solution. The solid-liquid ratio of lanthanum or cerium ions to water is 1:60 g / mL. Under stirring, add MnO2. The amount of MnO2 added is 3 times the molar amount of lanthanum or cerium ions. Stir ultrasonically at 20 kHz and 25 °C for 4 h. Filter, wash, and vacuum dry to obtain rare earth doped MnO2 composite material.
[0052] S3. According to the solid-liquid ratio of 1:20 g / mL, the rare earth-doped MnO2 composite material was dispersed in anhydrous ethanol, and maleic anhydride and p-toluenesulfonic acid were added. The mass ratio of the rare earth-doped MnO2 composite material to maleic anhydride and p-toluenesulfonic acid was 5:1:0.5. The reaction was carried out at 80℃ for 4 h to obtain the intermediate product.
[0053] S4. The intermediate product was dispersed in anhydrous ethanol at a solid-liquid ratio of 1:20 g / mL. Alkyl thiols and azobisisobutyronitrile were added, with a mass ratio of alkyl thiols and azobisisobutyronitrile to the intermediate product of 1:0.1:3. The mixture was reacted at 100℃ for 1 h, centrifuged, washed, and vacuum dried to obtain the thiol-rare earth hybrid MnO2 composite material.
[0054] Example 3
[0055] A wastewater treatment process, the specific treatment steps are as follows:
[0056] (1) Electrochemical catalytic oxidation: After homogenization in a pH adjustment tank (pH = 3-5), the aniline wastewater is introduced into an electrochemical catalytic device. A thiol-rare earth hybrid MnO2 composite material is filled between the three-dimensional electrodes, and the current is set to 30 mA / cm. 2 Electrochemical catalytic oxidation was carried out at 5V and 35℃ for 2 hours.
[0057] (2) Ozone catalysis: The wastewater after electrochemical catalytic oxidation is fed into the ozone catalytic oxidation device. The ozone concentration is set to 20 mg / L and the flow rate is 2 L / min. The catalytic reactor is filled with thiol-rare earth hybrid MnO2 composite material and the reaction is carried out for 40 min to obtain the treated wastewater.
[0058] (3) The treated wastewater is biochemically treated by biological contact oxidation.
[0059] The preparation methods of the thiol-rare earth hybrid MnO2 composite materials in (1) and (2) above include:
[0060] S1. Add potassium permanganate and manganese sulfate in a molar ratio of 1:3 to deionized water. The solid-liquid ratio of potassium permanganate to deionized water is 1:40 g / mL. Add sulfuric acid dropwise to adjust the pH value to 3.0±0.5. Transfer to a high-pressure reactor and hydrothermally react at 140℃ for 12 h. Wash and dry the product to obtain MnO2 powder.
[0061] S2. Add nitrate containing lanthanum or cerium ions to water to prepare a solution. The solid-liquid ratio of lanthanum or cerium ions to water is 1:80 g / mL. Under stirring, add MnO2. The amount of MnO2 added is 4 times the molar amount of lanthanum or cerium ions. Stir ultrasonically at 30 kHz and 35 °C for 6 h. Filter, wash, and vacuum dry to obtain rare earth doped MnO2 composite material.
[0062] S3. According to the solid-liquid ratio of 1:40 g / mL, the rare earth-doped MnO2 composite material was dispersed in anhydrous ethanol, and maleic anhydride and p-toluenesulfonic acid were added. The mass ratio of the rare earth-doped MnO2 composite material to maleic anhydride and p-toluenesulfonic acid was 7:1:0.8. The reaction was carried out at 90℃ for 6 h to obtain the intermediate product.
[0063] S4. The intermediate product was dispersed in anhydrous ethanol at a solid-liquid ratio of 1:30 g / mL. Alkyl thiols and azobisisobutyronitrile were added, with a mass ratio of alkyl thiols and azobisisobutyronitrile to the intermediate product of 1:0.3:5. The mixture was reacted at 120℃ for 3 h, centrifuged, washed, and vacuum dried to obtain the thiol-rare earth hybrid MnO2 composite material.
[0064] Comparative Example 1
[0065] The difference from Example 1 is that the thiol-rare earth hybrid MnO2 composite material is replaced with a thiol-MnO2 composite material, while the rest is the same as Example 1.
[0066] Comparative Example 2
[0067] The difference from Example 1 is that the thiol-rare earth hybrid MnO2 composite material is replaced with a rare earth-MnO2 composite material, while the rest is the same as Example 1.
[0068] Comparative Example 3
[0069] The difference from Example 1 is that the thiol-rare earth hybrid MnO2 composite material is not used; otherwise, it is the same as Example 1.
[0070] Test case
[0071] Aniline wastewater (pH = 6-9) containing 20,000 mg / L CODcr, 900 mg / L BOD5, and 80 mg / L aniline compounds was treated using the wastewater treatment processes described in Examples 1-3 and Comparative Examples 1-3, respectively. The concentrations of each pollutant in the effluent were tested, and the removal efficiency was calculated.
[0072] Removal efficiency = (Concentration in initial wastewater - Concentration in effluent wastewater) / Concentration in initial wastewater × 100%
[0073] The test results are shown in Table 1.
[0074] Table 1
[0075]
[0076] As can be seen from Table 1, the treatment processes of Examples 1-3 of the present invention can degrade pollutants in wastewater, enabling aniline wastewater to meet discharge standards.
[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A wastewater treatment process, characterized in that, Includes the following steps: First, the aniline wastewater is treated by electrochemical catalytic oxidation and ozone catalytic oxidation, and then biochemical treatment is carried out by biological contact oxidation to bring the aniline wastewater up to the sewage discharge standard. Both the electrochemical catalytic oxidation and ozone catalytic pretreatment stages incorporate thiol-rare earth hybrid MnO2 composite materials. The preparation method of the thiol-rare earth hybrid MnO2 composite material includes: (1) Add potassium permanganate and manganese sulfate to deionized water, add sulfuric acid dropwise to adjust the pH value to 2.5-3.5, transfer to a high pressure vessel for hydrothermal reaction, wash and dry to obtain MnO2 powder; (2) Add rare earth ions to water to prepare a solution, add MnO2 under stirring, stir ultrasonically, wash, and vacuum dry to obtain rare earth-doped MnO2 composite material. (3) Disperse the rare earth-doped MnO2 composite material in anhydrous ethanol, add maleic anhydride and p-toluenesulfonic acid to react and obtain the intermediate product. (4) The intermediate product was dispersed in anhydrous ethanol, and alkyl thiols and azobisisobutyronitrile were added to react. The mixture was then centrifuged, washed, and vacuum dried to obtain a thiol-rare earth hybrid MnO2 composite material.
2. The wastewater treatment process as described in claim 1, characterized in that, In the preparation method of thiol-rare earth hybrid MnO2 composite material, in step (1), the molar ratio of potassium permanganate and manganese sulfate is 1:1-3; the solid-liquid ratio of potassium permanganate and deionized water is 1:30-40 g / mL; and the hydrothermal reaction is carried out at 120-140℃ for 12 h.
3. The wastewater treatment process as described in claim 1, characterized in that, In the preparation method of thiol-rare earth hybrid MnO2 composite material, in step (2), the rare earth ion is a nitrate containing lanthanum ion or cerium ion; the solid-liquid ratio of the rare earth ion to water is 1:60-80g / mL; the amount of MnO2 added is 3-4 times the molar amount of rare earth ion; the ultrasonic stirring is carried out at 20-30kHz and 25-35℃ for 4-6h.
4. The wastewater treatment process as described in claim 1, characterized in that, In the preparation method of thiol-rare earth hybrid MnO2 composite material, in step (3), the solid-liquid ratio of the rare earth-doped MnO2 composite material to anhydrous ethanol is 1:20-40 g / mL; the mass ratio of the rare earth-doped MnO2 composite material to maleic anhydride and p-toluenesulfonic acid is 5-7:1:0.5-0.8; the reaction is carried out at 80-90℃ for 4-6 h.
5. The wastewater treatment process as described in claim 1, characterized in that, In the preparation method of thiol-rare earth hybrid MnO2 composite material, in step (4), the solid-liquid ratio of the intermediate product to anhydrous ethanol is 1:20-30 g / mL; the mass ratio of the alkyl thiol and azobisisobutyronitrile to the intermediate product is 1:0.1-0.3:3-5; the reaction temperature is 100-120℃ and the time is 1-3 h.
6. The wastewater treatment process as described in claim 1, characterized in that, The electrochemical catalytic oxidation specifically refers to: After homogenization in a pH adjustment tank, aniline wastewater is introduced into an electrochemical catalytic device. Thiol-rare earth hybrid MnO2 composite material is filled between three-dimensional electrodes for electrochemical catalytic oxidation.
7. The wastewater treatment process as described in claim 6, characterized in that, The pH adjustment tank is used to adjust the pH to 3-5; the electrochemical catalytic device is set with a current of 10-30 mA / cm². 2 Voltage 3-5V, temperature 25-35℃, time 1-2h.
8. The wastewater treatment process as described in claim 1, characterized in that, The ozone catalysis specifically refers to: The wastewater after electrochemical catalytic oxidation is fed into an ozone catalytic oxidation device. The catalytic reactor is filled with a thiol-rare earth hybrid MnO2 composite material to carry out the reaction and obtain the treated wastewater.
9. The wastewater treatment process as described in claim 8, characterized in that, The ozone catalytic oxidation device is set with an ozone concentration of 10-20 mg / L, a flow rate of 1-2 L / min, and a reaction time of 20-40 min.