Method for degrading organic pollutants in water by utilizing nitrilotriacetic acid and divalent manganese ion reinforced ferrate

Abstract

The invention relates to a method for degrading organic pollutants in water by utilizing nitrilotriacetic acid and divalent manganese ion reinforced ferrate, aiming at solving the problems that the ferrate is relatively low in organic pollutant degradation efficiency, low in organic pollutant removal rate and the like in an actual wastewater treatment process. The invention discloses a method for degrading organic pollutants in water by utilizing nitrilotriacetic acid and divalent manganese ion reinforced ferrate. The method comprises the following steps: 1, adjusting the pH value of wastewater containing the organic pollutants to be 7-8; 2, placing nitrilotriacetic acid in pure water, and stirring to obtain a nitrilotriacetic acid stock solution; 3, adding the nitrilotriacetic acid stock solution into the wastewater; 4, adding manganese salt into the micro-complex pollutant wastewater; and 5, adding ferrate into the manganese-containing micro-complex pollutant wastewater, and carrying out stirring reaction to degrade organic pollutants in the water. According to the method disclosed by the invention, a combination of nitrilotriacetic acid and divalent manganese is introduced into a ferrate oxidation system, so that various pollutants in water can be effectively removed, and the removal rate of the pollutants in the water reaches 90% or above within 30 minutes.

Description

Technical Field

[0001] This invention belongs to the field of water treatment, specifically relating to a method for enhancing the degradation of pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions. Background Technology

[0002] Ferrate is a commonly used water treatment agent, often acting as an oxidant, disinfectant, and coagulant. According to relevant research reports, ferrate has good removal effects on various organic pollutants in water, such as phenols, amines, and antibiotics. However, in actual wastewater treatment processes, due to competitive consumption by the complex background matrix in the water, the removal efficiency of ferrate for target pollutants is often lower than theoretically expected, which is one of the important factors limiting its application and development.

[0003] Existing methods for enhancing ferrate removal of pollutants often involve introducing external energy (such as ultraviolet light) or adding auxiliary materials (or reagents). These methods are often uneconomical and unsafe; for example, the introduced catalysts may be expensive or introduce secondary pollution, making them difficult to apply in practical water treatment scenarios. Therefore, there is an urgent need for a safe and effective method to improve the removal efficiency of ferrates for organic pollutants. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of low degradation efficiency of ferrates for organic pollutants and low removal rate of organic pollutants in actual wastewater treatment processes, and to provide a method for enhancing the degradation of organic pollutants in water by using nitric acid triacetic acid and divalent manganese ions.

[0005] This invention utilizes nitric acid triacetic acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrates, and is implemented according to the following steps:

[0006] 1. Adjust the pH of the wastewater containing organic pollutants to 7-8 to obtain the pollutant wastewater after pH adjustment;

[0007] 2. Place nitroglycerin in pure water and stir to obtain a nitroglycerin stock solution;

[0008] 3. Add nitric acid stock solution to the pH-adjusted pollutant wastewater and stir to obtain micro-complexed pollutant wastewater.

[0009] IV. Add manganese salt to the micro-complexed pollutant wastewater and stir to obtain manganese-containing micro-complexed pollutant wastewater;

[0010] V. Add ferrate to wastewater containing manganese micro-complexed pollutants, stir and react to complete the method of using nitric acid triacetic acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrate.

[0011] The molar ratio of divalent manganese (ions) in ferrate and manganese salt is controlled to be 1:0.4~1:3, and the molar ratio of ferrate and aminotriacetic acid is controlled to be 1:0.4~1:4.

[0012] The cost and safety of catalysts are often important factors limiting their application. The nitric acid used in this invention possesses excellent ability to complex metal ions. As a mature industrial raw material, nitric acid is low in cost, low in toxicity, and has good biodegradability, making it a safe water treatment agent.

[0013] Traditional catalytic methods that directly target active iron species often suffer from low utilization rates due to the rapid decay of iron species. In contrast, this invention introduces nitric acid and manganese ions as active mediators into the ferrate reaction system, providing a favorable micro-complexation environment for active iron / manganese oxide species. This micro-complexation environment promotes the formation of highly oxidizing manganese oxide species (Mn(III) and Mn(VII)) in the system, transferring the active host from iron species to the equally highly oxidizing and more stable manganese species. Furthermore, the micro-complexation environment effectively delays the decay of trivalent manganese oxide species, widening the reaction window and thus improving the utilization rate of pollutants to oxide species. Therefore, the nitric acid-divalent manganese-ferrate system exhibits excellent removal efficiency for organic pollutants in water.

[0014] The present invention utilizes nitric acid triacetic acid and divalent manganese ions to enhance the degradation of pollutants in water by ferrates, and has the following beneficial effects:

[0015] 1. The ferrate used in this invention is a green oxidant that leaves no residue and produces no harmful byproducts after the reaction, and has a low cost.

[0016] 2. The nitroglycerin used in this invention is a safe and inexpensive industrial raw material with low toxicity and good biodegradability, making it highly safe to use.

[0017] 3. The divalent manganese ions used in this invention will eventually be converted into manganese oxide (or hydroxide) precipitate after the reaction, resulting in low leakage risk and high safety;

[0018] 4. This invention, by introducing a combination of nitric acid triacetic acid and divalent manganese into the ferrate oxidation system, can effectively remove multiple pollutants from water, achieving a pollutant removal rate of over 90% within 30 minutes. Compared to using ferrate alone, this combination can improve the pollutant removal rate by 10% to 60% or more. Detailed Implementation

[0019] Specific Implementation Method 1: This implementation method, which utilizes aminotriacetic acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrates, is carried out according to the following steps:

[0020] 1. Adjust the pH of the wastewater containing organic pollutants to 7-8 to obtain the pollutant wastewater after pH adjustment;

[0021] 2. Place nitroglycerin in pure water and stir to obtain a nitroglycerin stock solution;

[0022] 3. Add nitric acid stock solution to the pH-adjusted pollutant wastewater and stir to obtain micro-complexed pollutant wastewater.

[0023] IV. Add manganese salt to the micro-complexed pollutant wastewater and stir to obtain manganese-containing micro-complexed pollutant wastewater;

[0024] V. Add ferrate to wastewater containing manganese micro-complexed pollutants, stir and react to complete the method of using nitric acid triacetic acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrate.

[0025] The molar ratio of divalent manganese (ions) in ferrate and manganese salt is controlled to be 1:0.4~1:3, and the molar ratio of ferrate and aminotriacetic acid is controlled to be 1:0.4~1:4.

[0026] In this embodiment, the wastewater containing organic pollutants in step one can be laboratory simulated water, municipal sewage, industrial wastewater, or polluted natural water bodies. The stirring reaction in step five is carried out at a temperature of approximately 20-30°C.

[0027] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the organic pollutants in the wastewater containing organic pollutants in step one are one or more of the following mixed pollutants: phenol, acetaminophen, bisphenol A, p-chlorophenol, and p-tert-butylphenol.

[0028] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the concentration of organic pollutants in the wastewater containing organic pollutants is 5~100μmol / L.

[0029] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that in step one, the pH of the wastewater containing organic pollutants is adjusted to 7~8 using nitric acid or sodium hydroxide solution.

[0030] Specific Implementation Method 5: This implementation method differs from Specific Implementation Methods 1 to 4 in that the concentration of the nitric acid stock solution in step 2 is 1 mol / L.

[0031] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that in step two, nitroglycerin is placed in pure water, and sodium hydroxide powder is added in multiple batches to aid dissolution.

[0032] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the stirring speed in steps Three to Five is controlled at 400~600 r / min.

[0033] Specific Implementation Method Eight: This implementation method differs from one of Specific Implementation Methods One to Seven in that the manganese salt mentioned in step four is manganese sulfate or manganese chloride.

[0034] In this embodiment, the added manganese salt is either a solid powder or an aqueous solution of manganese salt.

[0035] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the ferrate mentioned in step five is potassium ferrate.

[0036] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the molar ratio of divalent manganese ions in ferrate and manganese salt is controlled to be 1:1 to 1:2, and the molar ratio of ferrate and aminotriacetic acid is controlled to be 1:2 to 1:4.

[0037] This embodiment optimizes the ratio of ferrate, manganese salt and nitric acid. Within this ratio range, the ferrate-divalent manganese-nitric acid system has a significant removal effect on pollutants, and the effect is better than using ferrate alone.

[0038] Example 1: This example demonstrates a method for enhancing the degradation of organic pollutants in water using ferrates with triacetic acid and divalent manganese ions, implemented according to the following steps:

[0039] 1. Prepare a borate buffer solution, adjust the pH of the system to 8, add bisphenol A (50 μmol / L) to the borate buffer solution, and stir evenly at 500 r / min to obtain the pollutant wastewater after pH adjustment.

[0040] 2. Place nitroglycerin in deionized water and stir to obtain a 1 mol / L nitroglycerin stock solution.

[0041] 3. Add nitric acid stock solution to the polluted wastewater after pH adjustment to make the concentration of nitric acid in the polluted wastewater reach 200 μmol / L, and stir for 10 min to obtain micro-complexed polluted wastewater.

[0042] IV. Add manganese sulfate to the micro-complexed pollutant wastewater to make the concentration of divalent manganese ions reach 50 μmol / L, and stir for 10 min to obtain manganese-containing micro-complexed pollutant wastewater.

[0043] V. Add potassium ferrate powder to wastewater containing manganese micro-complexed pollutants to achieve a potassium ferrate concentration of 50 μmol / L. Stir magnetically at 500 r / min for 30 min to complete the method of using nitric acid triacetic acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrate.

[0044] In this embodiment, when the stirring reaction time in step five is 30 minutes, the removal rate of bisphenol A is 93%.

[0045] Comparative Example 2: This example demonstrates a method for degrading organic pollutants in water using ferrates, implemented according to the following steps:

[0046] 1. Prepare a borate buffer solution, adjust the pH of the system to 8, add bisphenol A (50 μmol / L) to the borate buffer solution, and stir evenly at 500 r / min to obtain the pollutant wastewater after pH adjustment.

[0047] 2. Add potassium ferrate powder to the polluted wastewater after pH adjustment to achieve a potassium ferrate concentration of 50 μmol / L, and magnetically stir at 500 r / min for 30 min to complete the method of degrading organic pollutants in water using ferrate.

[0048] In this embodiment, when the stirring reaction time in step two is 30 min, the removal rate of bisphenol A is 53%. In comparison, the method in Example 1, which utilizes nitric acid triacetic acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrates, achieves a bisphenol A removal rate of 93%, representing an improvement of 40%.

[0049] Comparative Example 3: This example demonstrates a method for degrading organic pollutants in water using divalent manganese in combination with ferrates, implemented according to the following steps:

[0050] 1. Prepare a borate buffer solution, adjust the pH of the system to 8, add bisphenol A (50 μmol / L) to the borate buffer solution, and stir evenly at 500 r / min to obtain the pollutant wastewater after pH adjustment.

[0051] 2. Add manganese sulfate to the polluted wastewater after pH adjustment to make the concentration of divalent manganese ions reach 50 μmol / L, and stir for 10 min to obtain manganese-containing polluted wastewater.

[0052] 3. Add potassium ferrate powder to the manganese-containing wastewater to achieve a potassium ferrate concentration of 50 μmol / L, and magnetically stir at 500 r / min for 30 min to complete the method of using divalent manganese in combination with ferrate to degrade organic pollutants in water.

[0053] In this embodiment, when the stirring reaction time in step three is 30 min, the removal rate of bisphenol A is 45%. In comparison, the method in Example 1, which utilizes nitric acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrates, achieves a bisphenol A removal rate of 93%, representing an improvement of 48%.

[0054] Comparative Example 4: This example demonstrates a method for degrading organic pollutants in water using nitric acid in combination with ferrate, implemented according to the following steps:

[0055] 1. Prepare a borate buffer solution, adjust the pH of the system to 8, add bisphenol A (50 μmol / L) to the borate buffer solution, and stir evenly at 500 r / min to obtain the pollutant wastewater after pH adjustment.

[0056] 2. Place nitroglycerin in deionized water and stir to obtain a 1 mol / L nitroglycerin stock solution.

[0057] 3. Add nitric acid stock solution to the polluted wastewater after pH adjustment to make the concentration of nitric acid in the polluted wastewater reach 200 μmol / L, and stir for 10 min to obtain micro-complexed polluted wastewater.

[0058] IV. Add potassium ferrate powder to the micro-complexed pollutant wastewater to achieve a potassium ferrate concentration of 50 μmol / L, and magnetically stir at 500 r / min for 30 min to complete the method of using nitric acid triacetic acid in combination with ferrate to degrade organic pollutants in water.

[0059] In this embodiment, when the stirring reaction time in step four is 30 min, the removal rate of bisphenol A is 75%. In comparison, the method in Example 1, which utilizes nitric acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrates, achieves a bisphenol A removal rate of 93%, representing an 18% improvement.

[0060] Example 5: This example demonstrates a method for enhancing the degradation of organic pollutants in water using ferrates with nitric acid and divalent manganese ions, implemented according to the following steps:

[0061] 1. Prepare a borate buffer solution and adjust the pH of the system to 8. Add phenol to the borate buffer solution with a concentration of 50 μmol / L and stir at 500 r / min until homogeneous to obtain the pollutant wastewater after pH adjustment.

[0062] 2. Place nitroglycerin in deionized water and stir to obtain a 1 mol / L nitroglycerin stock solution.

[0063] 3. Add triacetic acid stock solution to the polluted wastewater after pH adjustment to make the concentration of triacetic acid in the polluted wastewater reach 400 μmol / L, and stir for 10 min to obtain micro-complexed polluted wastewater.

[0064] IV. Add manganese sulfate to the micro-complexed pollutant wastewater to make the concentration of divalent manganese ions reach 100 μmol / L, and stir for 10 min to obtain manganese-containing micro-complexed pollutant wastewater.

[0065] V. Add potassium ferrate powder to the manganese-containing micro-complexed pollutant wastewater to achieve a potassium ferrate concentration of 100 μmol / L, and magnetically stir at 500 r / min for 30 min to complete the method of using nitric acid triacetic acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrate.

[0066] In this embodiment, when the stirring reaction time in step five is 30 min, the phenol removal rate is 95%. In comparison, the removal rate of phenol using the same dose of ferrate alone is 32%. The method of enhancing the degradation of organic pollutants in water by ferrate using nitric acid and divalent manganese ions increases the phenol removal rate by 63%.

[0067] Example 6: This example demonstrates a method for enhancing the degradation of organic pollutants in water using ferrates with nitric acid and divalent manganese ions, implemented according to the following steps:

[0068] 1. Prepare a borate buffer solution and adjust the pH of the system to 8. Add methyl phenyl sulfoxide (50 μmol / L) to the borate buffer solution and stir at 500 r / min until homogeneous to obtain the pollutant wastewater after pH adjustment.

[0069] 2. Place nitroglycerin in deionized water and stir to obtain a 1 mol / L nitroglycerin stock solution.

[0070] 3. Add nitric acid stock solution to the polluted wastewater after pH adjustment to make the concentration of nitric acid in the polluted wastewater reach 200 μmol / L, and stir for 10 min to obtain micro-complexed polluted wastewater.

[0071] IV. Add manganese sulfate to the micro-complexed pollutant wastewater to make the concentration of divalent manganese ions reach 50 μmol / L, and stir for 10 min to obtain manganese-containing micro-complexed pollutant wastewater.

[0072] V. Add potassium ferrate powder to wastewater containing manganese micro-complexed pollutants to achieve a potassium ferrate concentration of 50 μmol / L. Stir magnetically at 500 r / min for 30 min to complete the method of using nitric acid triacetic acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrate.

[0073] In this embodiment, when the stirring reaction time in step five is 30 min, the removal rate of methyl phenyl sulfoxide is 100%. In comparison, the removal rate of methyl phenyl sulfoxide using the same dose of ferrate alone is 59%. The method of enhancing the degradation of organic pollutants in water by ferrate using nitric acid and divalent manganese ions increases the removal rate of methyl phenyl sulfoxide by 41%.

Claims

1. A method for enhancing the degradation of organic pollutants in water using ferrates with nitric acid and divalent manganese ions, characterized in that... The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions is implemented according to the following steps:

1. Adjust the pH of the wastewater containing organic pollutants to 7-8 to obtain the pollutant wastewater after pH adjustment; 2. Place nitroglycerin in pure water and stir to obtain a nitroglycerin stock solution; 3. Add nitric acid stock solution to the pH-adjusted pollutant wastewater and stir to obtain micro-complexed pollutant wastewater. IV. Add manganese salt to the micro-complexed pollutant wastewater and stir to obtain manganese-containing micro-complexed pollutant wastewater; V. Add ferrate to wastewater containing manganese micro-complexed pollutants, stir and react to complete the method of using nitric acid triacetic acid and divalent manganese ions to enhance the degradation of organic pollutants in water by ferrate. The molar ratio of divalent manganese in ferrate and manganese salt is controlled to be 1:0.4~1:3, and the molar ratio of ferrate and aminotriacetic acid is controlled to be 1:0.4~1:

4.

2. The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions according to claim 1, characterized in that... The organic pollutants in the wastewater containing organic pollutants in step one are one or more of the following mixed pollutants: phenol, acetaminophen, bisphenol A, p-chlorophenol, and p-tert-butylphenol.

3. The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions according to claim 1, characterized in that... The concentration of organic pollutants in wastewater containing organic pollutants is 5~100 μmol / L.

4. The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions according to claim 1, characterized in that... In step one, the pH of the wastewater containing organic pollutants is adjusted to 7-8 using nitric acid or sodium hydroxide solution.

5. The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions according to claim 1, characterized in that... In step two, the concentration of the nitric acid stock solution is 1 mol / L.

6. The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions according to claim 1, characterized in that... In step two, nitroglycerin is placed in pure water, and sodium hydroxide powder is added in several portions to aid dissolution.

7. The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions according to claim 1, characterized in that... In steps three through five, the stirring speed is controlled to be 400-600 r / min.

8. The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions according to claim 1, characterized in that... The manganese salt mentioned in step four is manganese sulfate or manganese chloride.

9. The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions according to claim 1, characterized in that... The ferrate mentioned in step five is potassium ferrate.

10. The method for enhancing the degradation of organic pollutants in water using ferrates with aminotriacetic acid and divalent manganese ions according to claim 1, characterized in that... The molar ratio of divalent manganese ions in ferrate and manganese salt is controlled to be 1:1 to 1:2, and the molar ratio of ferrate and aminotriacetic acid is controlled to be 1:2 to 1:4.