A method for electrochemically synergizing activated peracetic acid with carbon nanotubes to degrade organic micropollutants

Abstract

The application discloses a method for degrading organic micro-pollutants by electrochemical synergic activated peracetic acid and carbon nanotubes, which comprises the following steps: adding organic micro-pollutants into a reaction solution containing peracetic acid and carbon nanotubes, and degrading the organic micro-pollutants by applying power to the cathode and the anode; wherein the pH value of the reaction solution is 3-11, and the current density is 0.5-5 mA cm ‑2 . The method can efficiently remove the organic micro-pollutants, and the current efficiency is high.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a method for electrochemically synergistically activating peracetic acid with carbon nanotubes to degrade organic micropollutants. Background Technology

[0002] With the acceleration of urbanization and industrialization, large amounts of toxic and harmful synthetic organic compounds, such as dyes, phenols, antibiotics, and personal care products, enter the urban water cycle. This poses significant ecological risks to the natural aquatic ecosystem and also creates hidden dangers for the reuse of industrial wastewater and urban sewage. Advanced oxidation technologies offer significant advantages for the removal of these organic pollutants. Peracetic acid-activated advanced oxidation methods have become a research hotspot in recent years and show promising application prospects.

[0003] Peracetic acid (PAA) is activated to produce organic free radicals (RO·:CH3C(=O)OO· and CH3C(=O)O·), hydroxyl radicals (·OH), and singlet oxygen (…). 1 O2) and superoxide anion radicals (O2· - It can efficiently degrade organic pollutants in water.

[0004] However, the activation methods for peracetic acid are still in the preliminary research stage. Currently, the only methods for activating peracetic acid include ultraviolet light activation, metal ion activation, and activation using modified carbon materials. However, ultraviolet light activation requires a large amount of external energy, metal ion activation has the problem of ion leakage leading to secondary pollution, and carbon material activation has the problem of low efficiency.

[0005] Patent application CN111252865A discloses a method for treating organic wastewater using an electrochemical synergistic peracetic acid system, belonging to the field of water pollution control technology. The method for treating organic wastewater using an electrochemical synergistic peracetic acid system provided by this invention includes the following steps: mixing organic wastewater and peracetic acid in an electrochemical reactor, and then performing an electrochemical oxidation reaction after connecting a power source; the pH value of the organic wastewater is 4–11.

[0006] In the method provided by the aforementioned patent application, organic pollutants are directly oxidized on the surface of the anode electrode through electron transfer or by oxidization from hydroxyl radicals, acyl groups, and peroxyacyl groups generated by electrochemically activated peracetic acid, resulting in high degradation efficiency for organic pollutants in organic wastewater. Peracetic acid also acts as an electrolyte, eliminating the need for additional electrolytes and thus increasing the reaction rate of the electrochemical system. Furthermore, peracetic acid also has a disinfecting and sterilizing effect. The method provided by this invention has a wide applicable pH range and excellent degradation effect on organic pollutants. However, this method requires a high current density and a long reaction time.

[0007] Electrochemical methods (EC) have demonstrated great potential in the treatment of organic wastewater. However, traditional EC technologies have drawbacks, such as high energy consumption and low stability. Limited effective electrode area and low current efficiency are major limiting factors in the electroactivation process, and their high cost makes them unsuitable for practical applications. Therefore, there is an urgent need to design a preparation method that achieves high removal efficiency of organic pollutants while maintaining high current utilization. Summary of the Invention

[0008] This invention provides a method for electrochemically synergistically activating peracetic acid with carbon nanotubes to degrade organic micropollutants. This method can efficiently remove organic micropollutants and has high current efficiency.

[0009] This invention provides a method for electrochemically synergistically activating peracetic acid to degrade organic micropollutants using carbon nanotubes, comprising:

[0010] Organic micropollutants are added to a reaction solution containing peracetic acid and carbon nanotubes, and electricity is applied to the cathode and anode electrodes through a power source to degrade the organic micropollutants.

[0011] The reaction solution has a pH of 3-11 and a current density of 0.25-10 mA / cm². -2 .

[0012] Organic micropollutants are added to the mixture, the electrochemical device is turned on, and the resulting reaction solution is subjected to degradation treatment. In the method for treating organic micropollutants using an electrochemically synergistic carbon nanotube-activated peracetic acid system provided by this invention, peracetic acid is directly activated and decomposed at the anode into organic free radicals (RO·:CH3C(=O)OO· and CH3C(=O)O·) and oxygen (O2). O2 is activated to generate singlet oxygen (…). 1 O2 gains electrons at the cathode to generate superoxide anion (O2· - This can further activate CH3C(=O)OO· to ​​generate CH3C(=O)O· and 1 O2, and peracetic acid can be activated by electrochemical systems under a wide pH range (3-11). Furthermore, peracetic acid gains and loses electrons near the electrode, transforming into organic free radicals (RO·:CH3C(=O)OO· and CH3C(=O)O·) and hydroxyl free radicals (·OH), singlet oxygen (…). 1 O2) and superoxide anion radicals (O2· -Compared to H2O2 and PMS, the peracetic acid used in this invention can be activated by the electrochemical system over a wide pH range (3-11), generating more strong oxidizing free radicals, resulting in higher degradation efficiency for organic pollutants and no secondary pollution. The method provided by this invention is suitable for treating organic micro-polluting wastewater, with a wide applicable pH range, mild reaction conditions, simple operation, low energy consumption, and small dosage, showing broad application prospects in the degradation and removal of pollutants in water.

[0013] Preferably, the concentration of peracetic acid in the reaction solution is 0.1-2.5 mM, and the concentration of carbon nanotubes is 0.01-0.07 mM. An appropriate amount of carbon nanotubes can activate peracetic acid and also form appropriate amounts of positive and negative carbon nanotube electrodes, promoting the electro-activation of peracetic acid.

[0014] More preferably, the concentration of peracetic acid in the reaction solution is 0.5-1.5 mM, and the concentration of carbon nanotubes is 30-70 mg / L. -1 A relatively large amount of peracetic acid, combined with an appropriate amount of carbon nanotubes, can degrade organic micropollutants in a short time, with a degradation rate of over 90%.

[0015] Preferably, the current density is 0.5-5 mA cm⁻¹. -2 A suitable current density can electroactivate peracetic acid while also enabling carbon nanotubes to conduct electricity and form electrodes. It also minimizes the impact of rapid carbon nanotube movement on the combined positive and negative electrodes, which could cause some of the carbon nanotube electrode effects to disappear and affect the activation of peracetic acid.

[0016] More preferably, the concentration of peracetic acid in the reaction solution is 0.5-1 mM, and the concentration of carbon nanotubes is 50-70 mg / L. -1 The current density is 0.5-2 mA cm⁻¹ -2 The effect is better when the three are positively correlated.

[0017] Preferably, the carbon nanotubes are multi-walled carbon nanotubes with a length of 10-30 μm.

[0018] Preferably, both the cathode and anode are mixed metal oxides (Ti / IrO2-Ta2O5, MMO). Mixed metal oxides, as cathode and anode electrodes, exhibit good activation effects for peracetic acid.

[0019] Preferably, the pH of the reaction solution is 7-9. Electrode activation of peracetic acid exhibits good activation effect under neutral and weakly alkaline conditions.

[0020] Preferably, the reaction solution containing peracetic acid and carbon nanotubes is prepared, comprising:

[0021] A peracetic acid solution and an electrolyte solution are mixed to obtain a mixed solution. Carbon nanotubes are then added to the mixed solution to obtain a reaction solution. The concentration of the peracetic acid solution is 0.1-2.5 mM, and the concentration of the electrolyte solution is 5-10 mM.

[0022] Preferably, the power supply is a DC power supply with a current of 0.087A-0.87A, corresponding to a current density of 0.5-5mA / cm². -2 .

[0023] Preferably, the organic micropollutant is propranolol (PPL), sulfamethoxazole (SDZ), or tetracycline (TCH), and the concentration of the organic micropollutant in the reaction solution is 5-10 μM.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention promotes the activation of peracetic acid by carbon nanotubes by forming multiple small electrodes under the action of current at an appropriate current density. At the same time, the effect of carbon nanotubes further promotes the activation of peracetic acid by current in the cathode and anode electrodes. Therefore, under the synergistic effect of carbon nanotubes and electroactivation, the activation efficiency of peracetic acid can be improved at a relatively low current density. Attached Figure Description

[0026] Figure 1 These are schematic diagrams of the apparatus used in embodiments 1-23 of the present invention;

[0027] Figure 2 The degradation effect of propranolol solution provided in Examples 1, 2 and Comparative Examples 1-5 is shown in the figure.

[0028] Figure 3 XPS spectra of O1s in unactivated and electroactivated carbon nanotubes;

[0029] Figure 4 The degradation effects of tetracycline (Example 2) and sulfadiazine (Example 3) after 20 min of electrostatic reaction provided in Examples 2 and 3 are shown in the graphs.

[0030] Figure 5 The degradation effect of propranolol provided in Examples 1 and 5-7 is illustrated.

[0031] Figure 6 The degradation effect of propranolol provided in Examples 1 and 8-12 is illustrated in the diagram.

[0032] Figure 7 The degradation effect of propranolol provided in Examples 1 and 13-16 is illustrated in the diagram.

[0033] Figure 8 The degradation effect of propranolol provided in Examples 1 and 17-19 is illustrated in the diagram.

[0034] Figure 9 The degradation effect of propranolol provided in Examples 1 and 20-23 is shown in the figure. Detailed Implementation

[0035] This invention provides a method for treating organic wastewater using an electrochemical synergistic peracetic acid system, comprising the following steps:

[0036] Organic wastewater, peracetic acid, and carbon nanotubes are mixed in an electrochemical reactor, organic micro-pollutants are added, and an electrochemical oxidation reaction is carried out after the power is turned on.

[0037] In this invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

[0038] In this invention, the pH value of the mixture is preferably 5-9, more preferably 7-9. In this invention, when the pH value of the organic wastewater itself is not between 7 and 9, it is preferable to adjust the pH value of the organic wastewater to the above range. This invention does not specifically limit the pH adjusting agent used for pH adjustment, such as perchloric acid solution or sodium hydroxide solution.

[0039] In this invention, the peracetic acid is added in the form of an aqueous peracetic acid solution, the concentration of which is preferably 10-20 wt% (1.3 mM-2.6 mM), more preferably 10-18 wt% (1.3 mM-2.3 mM), and even more preferably 10-15 wt% (1.3 mM-2.0 mM).

[0040] In this invention, the temperature of the catalytic reaction is preferably 20-25°C.

[0041] In this invention, the rotor speed of the magnetic stirrer is 300 r / min.

[0042] In this invention, the carbon nanotubes are added in powder form and thoroughly mixed in the solution.

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0044] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents, materials and equipment are commercially available.

[0045] The method of electrochemically activated peracetic acid for treating antibiotic wastewater of the present invention is as follows: Figure 1The water treatment system includes a power supply and a reactor. An electrode holder is installed at the top of the reactor. Both the anode and cathode electrodes are rectangular thin plates, each 4×2cm in size, placed parallel to each other and 1cm apart, connected to an external DC power supply via wires. The DC power supply has a current of 0.087-0.87A, corresponding to a current density of 0.5-5mA / cm². -2 The mixed metal oxide electrode, used as both anode and cathode, can effectively activate peracetic acid, and the electrode sheet exhibits recyclability and stability in the degradation of antibiotic wastewater.

[0046] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0047] Example 1

[0048] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0049] Example 2

[0050] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 1 mM peracetic acid was adjusted to 9. 0.007 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 1 mM, and the concentration of carbon nanotubes was 70 mg / L. -1 (Specific values ​​provided) The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after connecting a DC power supply. The current density was 2mA / cm². -2 .

[0051] Comparative Example 1

[0052] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the pollutant propranolol was added, and the reaction was carried out for 20 minutes without electricity. The current density was 1mA / cm². -2 .

[0053] Comparative Example 2

[0054] At room temperature, 100 mL of 10 mM NaClO4 was added to an electrochemical reactor (4 cm × 2 cm × 1 mm) using mixed metal oxides as the anode and cathode electrodes. 5 μM of the contaminant propranolol was added, and the reaction was carried out for 20 min after a DC power supply was applied. The current density was 1 mA cm⁻¹. -2 .

[0055] Comparative Example 3

[0056] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. This solution was then added to an electrochemical reactor (4 cm × 2 cm × 1 mm) with mixed metal oxides as the anode and cathode electrodes. 5 μM of the contaminant propranolol was added, and the reaction was carried out for 20 min after connecting a DC power supply. The current density was 1 mA cm⁻¹. -2 .

[0057] Comparative Example 4

[0058] At room temperature, 0.005 g of carbon nanotubes were added to a solution containing 5 μM of the contaminant propranolol, resulting in a carbon nanotube concentration of 50 mg / L. -1 React for 20 minutes.

[0059] Comparative Example 5

[0060] At room temperature, the pH of a 100 mL solution of 0.5 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were added, mixed thoroughly, and then added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4 cm × 2 cm × 1 mm). 5 μM of the contaminant propranolol was added, and the reaction was carried out for 20 min without electricity. The current density was 1 mA / cm². -2 .

[0061] The ratio (c / c0) of the residual amount of propranolol to the initial amount at different reaction times provided in Examples 1 and Comparative Examples 1-5 is shown in Table 1. Figure 2 As shown.

[0062] From Table 1 and Figure 2 It can be seen that after 20 min of reaction, the removal rate of propranolol was only 11.62% under the action of peracetic acid alone (Comparative Example 1); 23.26% under the action of the electrochemical system alone (Comparative Example 2); 52.31% under the action of the electroactivated peracetic acid system (Comparative Example 3); 47.00% under the action of carbon nanotubes alone (Comparative Example 4); 64.24% under the action of carbon nanotube activated peracetic acid (Comparative Example 5); and the removal rate of propranolol increased to 90.32% under the action of the electrochemical synergistic carbon nanotube activated peracetic acid system (Example 1), with a synergistic factor of 3. Figure 3 XPS spectra of O1s in unactivated and electroactivated carbon nanotubes are shown. The peaks at 530.5 eV, 531.8 eV, 532.6 eV, and 533.1 eV are attributed to lattice oxygen (O1s). lat The presence of C=O, CO, and OH groups demonstrates that carbon nanotubes contain abundant oxidation sites, and the content of lattice oxygen increases after activation, thereby generating reactive oxygen species that activate peracetic acid. This indicates that the electrochemically synergistic carbon nanotube-activated peracetic acid system provided by this invention has excellent degradation effects on propranolol in treating organic wastewater.

[0063] Table 1. Ratio of residual to initial amount of propranolol in Example 1 and Comparative Examples 1-5 (c / c0)

[0064]

[0065] Example 3

[0066] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4cm×2cm×1mm). 5μM of the contaminant sulfadiazine (SDZ) was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0067] Example 4

[0068] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4cm×2cm×1mm). 5μM tetracycline (TCH) was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0069] The ratio (c / c0) of the remaining amount of propranolol to the initial amount at different reaction times according to the methods provided in Examples 1 and 3-4 is shown in Table 2. Figure 4 As shown in Table 2 and Figure 4 It was found that after 20 minutes of reaction, the removal efficiencies for sulfadiazine and tetracycline were 87% and 75%, respectively. This indicates that the electrochemically synergistic carbon nanotube-activated peracetic acid system provided by this invention has excellent degradation effects on several pollutants.

[0070] Table 2. Ratio of residual to initial organic micropollutants in Examples 1, 3, and 4 (c / c0)

[0071]

[0072] Example 5

[0073] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4cm×2cm×1mm). 5μM of the contaminant sulfadiazine (SDZ) was added, and the reaction was carried out for 20 minutes after the DC power supply was turned on, with a current density of 0.5mA / cm². -2 .

[0074] Example 6

[0075] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4cm×2cm×1mm). 5μM of the contaminant sulfadiazine (SDZ) was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 2mA / cm². -2 .

[0076] Example 7

[0077] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4cm×2cm×1mm). 5μM of the contaminant sulfadiazine (SDZ) was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 5mA / cm². -2 .

[0078] The ratio (c / c0) of the remaining amount of propranolol to the initial amount at different reaction times provided in Examples 5-7 is shown in Table 3. Figure 5 As shown.

[0079] In Experiment 5, the degradation rate reached 89% after 20 minutes; in Experiment 6, the degradation rate reached 88% after 20 minutes; and in Experiment 7, the degradation rate reached 85% after 20 minutes. All of these rates were lower than those in Experiment 1. This indicates that in a three-dimensional system, a higher current density is not necessarily better. Only a weak current is needed to form a three-dimensional system and promote the activation of peracetic acid.

[0080] Table 3. Ratio of remaining to initial amount of propranolol in Examples 1 and 5-7 (c / c0)

[0081]

[0082] Example 8

[0083] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.1 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0084] Example 9

[0085] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.25 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0086] Example 10

[0087] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.75 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0088] Example 11

[0089] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 1 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0090] Example 12

[0091] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 2.5 mM peracetic acid was adjusted to 9. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0092] The ratio (c / c0) of the remaining amount of propranolol to the initial amount at different reaction times provided in Examples 8-12 is shown in Table 4. Figure 6 As shown.

[0093] From Table 4 and Figure 6 It can be seen that when the initial concentration of peracetic acid is 0.1 mM, 0.25 mM, 0.5 mM, 0.75 mM, 1 mM and 2.5 mM, the removal rates of propranolol after 20 minutes of electrolysis are 71%, 79%, 93%, 94%, 95% and 97%, respectively.

[0094] Table 4. Ratio of remaining to initial amount of propranolol in Examples 1 and 8-12 (c / c0)

[0095]

[0096] Example 13

[0097] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 3. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm².-2 .

[0098] Example 14

[0099] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 5. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0100] Example 15

[0101] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 7. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0102] Example 16

[0103] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 11. 0.005 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 50 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0104] The ratio (c / c0) of the remaining amount of propranolol to the initial amount at different reaction times provided in Examples 13-16 is shown in Table 5. Figure 7 As shown.

[0105] From Table 5 and Figure 7 It can be seen that when the initial pH is 3, 5, 7, 9 and 11, the removal rates of propranolol after 20 minutes of electrolysis are 78%, 72%, 85%, 93% and 78%, respectively. This indicates that weak alkalinity (pH=7-9) is most favorable for the reaction.

[0106] Table 5. Ratio of remaining to initial amount of propranolol in Examples 1 and 13-16 (c / c0)

[0107]

[0108]

[0109] Example 17

[0110] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.001 g of carbon nanotubes was then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 10 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0111] Example 18

[0112] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.003 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 30 mg / L. -1 The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0113] Example 19

[0114] At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.007 g of carbon nanotubes were then added and mixed to obtain a reaction solution. The concentration of peracetic acid in this reaction solution was 0.5 mM, and the concentration of carbon nanotubes was 70 mg / L. -1The reaction solution was added to an electrochemical reactor (4cm×2cm×1mm) with mixed metal oxides as the anode and cathode electrodes. 5μM of the contaminant propranolol was added, and the reaction was carried out for 20 minutes after a DC power supply was applied. The current density was 1 mA / cm². -2 .

[0115] The ratio (c / c0) of the remaining amount of propranolol to the initial amount at different reaction times provided in Examples 13-16 is shown in Table 5. Figure 7 As shown.

[0116] From Table 6 and Figure 8 It can be seen that when the dosage of carbon nanotubes is 10 mg / L... -1 30mg L -1 50mg L -1 and 70mg L -1 When the electrostatic reaction was carried out for 20 minutes, the removal rates of propranolol were 75%, 83%, 93%, 93%, and 95%, respectively.

[0117] Table 6. Ratio of remaining to initial amount of propranolol in Examples 1 and 17-19 (c / c0)

[0118]

[0119] Example 20

[0120] The solution from Example 1 was filtered, and the carbon nanotubes were collected and dried for later use. At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of dried carbon nanotubes were added, mixed thoroughly, and then added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4 cm × 2 cm × 1 mm). The reactor was powered by a DC power supply and reacted for 20 min at a current density of 1 mA cm⁻¹. -2 .

[0121] Example 21

[0122] The solution after the reaction in Example 14 was filtered, and the carbon nanotubes were collected and dried for later use. At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of dried carbon nanotubes were added, mixed thoroughly, and then added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4 cm × 2 cm × 1 mm). The reactor was powered by a DC power supply and reacted for 20 min at a current density of 1 mA cm⁻¹. -2 .

[0123] Example 22

[0124] The solution from the reaction in Example 15 was filtered, and the carbon nanotubes were collected and dried for later use. At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of dried carbon nanotubes was added, mixed thoroughly, and then added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4 cm × 2 cm × 1 mm). The reactor was powered by a DC power supply and reacted for 20 min at a current density of 1 mA / cm². -2 .

[0125] Example 23

[0126] The solution from the reaction in Example 16 was filtered, and the carbon nanotubes were collected and dried for later use. At room temperature, the pH of a solution containing 100 mL of 10 mM NaClO4 and 0.5 mM peracetic acid was adjusted to 9. 0.005 g of dried carbon nanotubes were added, mixed thoroughly, and then added to an electrochemical reactor with mixed metal oxides as the anode and cathode electrodes (4 cm × 2 cm × 1 mm). The reactor was powered by a DC power supply and reacted for 20 min at a current density of 1 mA / cm². -2 .

[0127] The ratio (c / c0) of the remaining amount of propranolol to the initial amount at different reaction times provided in Examples 20-23 is shown in Table 6. Figure 9 As shown.

[0128] From Table 7 and Figure 9 It can be seen that when the number of cycles of carbon nanotubes is 1, 2, 3, 4 and 5, the removal rates of propranolol after 20 minutes of electrolysis are 93%, 92%, 85%, 83% and 82%, respectively, which indicates that carbon nanotubes can be recycled multiple times.

[0129] Table 7. Ratio of remaining to initial amount of propranolol in Examples 1 and 20-23 (c / c0)

[0130]

Claims

1. A method for electrochemically synergistically activating peracetic acid with carbon nanotubes to degrade organic micropollutants, characterized in that, include: Organic micropollutants are added to a reaction solution containing peracetic acid and carbon nanotubes, and electricity is applied to the cathode and anode electrodes through a power source to degrade the organic micropollutants. The reaction solution has a pH of 7-9 and a current density of 0.5-2 mA / cm². 2 ; Both the cathode and anode electrodes are mixed metal oxides, and the mixed metal oxides are Ti / IrO2-Ta2O5.

2. The method for electrochemically synergistically activating peracetic acid to degrade organic micropollutants according to claim 1, characterized in that, The concentration of peracetic acid in the reaction solution is 0.1-2.5 mM, and the concentration of carbon nanotubes is 10-70 mg / L.

3. The method for electrochemically synergistically activating peracetic acid to degrade organic micropollutants according to claim 2, characterized in that, The concentration of peracetic acid in the reaction solution is 0.5-1.5 mM, and the concentration of carbon nanotubes is 30-70 mg / L.

4. The method for electrochemically synergistically activating peracetic acid to degrade organic micropollutants according to claim 1, characterized in that, The concentration of peracetic acid in the reaction solution is 0.5-1 mM, and the concentration of carbon nanotubes is 50-70 mg / L.

5. The method for electrochemically synergistically activating peracetic acid to degrade organic micropollutants according to claim 1, characterized in that, The carbon nanotubes are multi-walled carbon nanotubes with a length of 10-30 μm.

6. The method for electrochemically synergistically activating peracetic acid to degrade organic micropollutants according to claim 1, characterized in that, Prepare a reaction solution containing peracetic acid and carbon nanotubes, including: A peracetic acid solution and an electrolyte solution are mixed to obtain a mixed solution. Carbon nanotubes are then added to the mixed solution to obtain a reaction solution. The concentration of the peracetic acid solution is 0.1-2.5 mM, and the concentration of the electrolyte solution is 5-10 mM.

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