A method for degrading organic pollutants in water by activating peroxybicarbonate with cobalt-containing zeolite nanosheets.

Abstract

This invention discloses a method for degrading organic pollutants in water by activating bicarbonate with cobalt-containing zeolite nanosheets. The method utilizes cobalt-containing zeolite nanosheet catalysts to activate bicarbonate and degrade organic pollutants in water. The cobalt-containing zeolite nanosheets are prepared by sequentially mixing tetrapropylammonium hydroxide, water, urea, tetraethyl orthosilicate, and cobalt acetylacetonate, followed by hydrothermal reaction and calcination. In this method, the cobalt-containing zeolite nanosheets exhibit uniform active sites, good stability, and low cobalt ion leaching. When used to activate bicarbonate, they significantly enhance the removal efficiency of organic pollutants, offering advantages such as good degradation effect, low cobalt ion leaching concentration, low cost, wide pH applicability, and no secondary pollution. Therefore, it has high practical value and promising application prospects.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology and relates to a method for degrading organic pollutants in water by activating peroxybicarbonate with cobalt-containing zeolite nanosheets. Background Technology

[0002] Human activities have led to the discharge of large amounts of recalcitrant organic matter into water bodies, causing water pollution, water quality degradation, and threatening human health and ecological security. Water pollution control has become a hot research topic. Currently, commonly used wastewater treatment technologies are categorized into biological, physical, and chemical remediation technologies. Among these, chemical remediation technologies, represented by advanced oxidation processes (AOPs), are considered the most productive and promising wastewater treatment and remediation technologies due to their superior performance. The Fenton process, as a type of AOP, features strong oxidizing power, low initial cost, and flexible operation. However, the classic homogeneous Fenton reaction has limitations such as a narrow pH range (generally 2-3), difficulties in separation and recovery, and secondary pollution.

[0003] Adding bicarbonate to the classic Fenton system, specifically by activating H₂O₂ with NaHCO₃, is known as peroxybicarbonate advanced oxidation technology. This technology not only improves reaction efficiency but also effectively avoids aquatic acidification, attracting increasing attention in recent years. Existing reports on peroxybicarbonate advanced oxidation technologies for removing organic pollutants from water mainly utilize transition metal ions, metal oxides, metal sulfides, and supported catalysts. Among these, supported catalysts, compared to other activators, exhibit lower leaching transition metal content, greater stability, and greater environmental friendliness, and have been extensively studied. Currently, commonly used supported catalysts include materials such as metal-organic frameworks, diatomaceous earth, silica, carbon, and zeolites, but all have obvious drawbacks. For example, some researchers have chosen diatomaceous earth as a support for Co and activated it with percarbonate. A 98% decolorization rate of methylene blue can be achieved in 5 hours, with Co ion leaching of 0.2 mg / L. However, the overall degradation efficiency of this method is low, and the required reaction time is long. Other researchers have used a solvothermal method to load Co nanoparticles into hollow bimetallic metal-organic framework materials and degrade 40 μmol / L sulfamethoxazole by activating percarbonate. The degradation rate is 98.9% within 60 minutes, with Co ion leaching of approximately 0.16 mg / L. Researchers have prepared a porous carbon sphere-encapsulated CoCu bimetallic catalyst using a gel lysis method. This catalyst was used to activate bicarbonate to degrade 10 mg / L norfloxacin, achieving a 100% removal rate within 120 minutes, with Co ion leaching at 0.2 mg / L and Cu ion leaching at 0.1 mg / L. Other researchers prepared a Co3O4-SiO2 nanocomposite material using a sol-gel chemical rapid thermal method. This material degraded Acid Orange in an activated bicarbonate system, achieving a near 100% degradation rate within 20 minutes. Immersion tests showed the material leachates at approximately 0.6 mg / L. Still other researchers loaded Co3O4 onto MCM-41 molecular sieves and degraded Acid Orange 7 dye using activated bicarbonate, achieving only a 70% degradation rate within 60 minutes. In general, current supported catalysts for activating percarbonate either exhibit low degradation efficiency requiring long reaction times, insufficient removal of organic pollutants, or high metal leaching rates, failing to effectively balance efficient degradation of organic pollutants with low metal leaching. In fact, catalysts prepared or modified using different methods differ in surface structure, electron density, and active sites, resulting in significantly varying activation effects on oxidation systems. Furthermore, metal-supported catalysts prepared using different processes also exhibit substantial differences in metal ion leaching rates during use. Currently, there are no reports of supported catalysts or degradation methods capable of efficiently degrading recalcitrant organic compounds (such as pharmaceuticals) while simultaneously achieving low metal ion leaching.Therefore, it is of great significance to develop a supported catalyst and method that can efficiently activate peroxybicarbonate to degrade organic pollutants in water without causing secondary pollution. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for degrading organic pollutants in water by activating peroxybicarbonate with cobalt-containing zeolite nanosheets, which has high degradation efficiency and low metal leaching.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0006] A method for degrading organic pollutants in water by activating percarbonate with cobalt-containing zeolite nanosheets is disclosed. The method involves using cobalt-containing zeolite nanosheets as a catalyst to activate percarbonate and degrade organic pollutant wastewater. The cobalt-containing zeolite nanosheets are prepared by sequentially mixing tetrapropylammonium hydroxide, water, urea, tetraethyl orthosilicate, and cobalt acetylacetonate, followed by hydrothermal reaction and calcination.

[0007] A further improvement to the above method is that the preparation steps of the cobalt-containing zeolite nanosheets include: S1. Mix tetrapropylammonium hydroxide, water and urea, and stir to obtain mixed solution A; S2. Add tetraethyl orthosilicate to the mixed solution A and stir to obtain mixed solution B; S3. Add cobalt acetylacetone to the mixed solution B and stir to obtain mixed solution C; S4. Perform a hydrothermal reaction on the mixed solution C; S5. The product of the hydrothermal reaction is calcined to obtain cobalt-containing zeolite nanosheets.

[0008] In a further improvement to the above method, in step S1, the stirring time is 1 h to 3 h; In step S2, the stirring time is 5 h to 8 h; In step S3, the stirring time is 1 h to 3 h.

[0009] In a further improvement to the above method, the mass ratio of tetrapropylammonium hydroxide, urea, tetraethyl orthosilicate, cobalt acetylacetonate, and water is 13.01:0.96:8.32:0.5:15.45.

[0010] In a further improvement to the above method, in step S4, the hydrothermal reaction temperature is 150℃~180℃, and the hydrothermal reaction time is 70h~96h.

[0011] In a further improvement to the above method, in step S5, the calcination temperature is 500℃~600℃, the calcination heating rate is 1℃ / min~5℃ / min, and the calcination time is 4h~8h.

[0012] The above method is further improved in step S3, which includes the following treatment after the hydrothermal reaction: washing and drying the reaction product; the washing is performed by washing with water 5 to 8 times, the drying temperature is 80℃ to 105℃, and the drying time is 10h to 14h.

[0013] A further improvement to the above method is that the degradation treatment involves mixing bicarbonate, cobalt-containing zeolite nanosheets, and organic pollutant wastewater, adding hydrogen peroxide solution, and carrying out a catalytic degradation reaction.

[0014] In a further improvement to the above method, the concentration of bicarbonate in the organic pollutant wastewater is 5 mmol / L to 50 mmol / L, the concentration of hydrogen peroxide in the organic pollutant wastewater is 10 mmol / L to 100 mmol / L, the concentration of cobalt-containing zeolite nanosheets in the organic pollutant wastewater is 0.1 g / L to 0.6 g / L, the initial concentration of organic pollutants in the organic pollutant wastewater is ≤10 mg / L, and the initial concentration of the hydrogen peroxide solution is 1 mol / L.

[0015] In a further improvement to the above method, the bicarbonate is sodium bicarbonate and / or potassium bicarbonate.

[0016] In a further improvement to the above method, the organic pollutants in the organic-polluted wastewater are at least one of acetaminophen, sulfamethoxazole, tetracycline hydrochloride, and bisphenol A.

[0017] In a further improvement to the above method, the mixing process of the bicarbonate, cobalt-containing zeolite nanosheets, and organic pollutant wastewater is carried out under stirring conditions, wherein the stirring speed is 300 r / min to 400 r / min, the stirring time is 30 min to 60 min, the catalytic degradation reaction time is 40 min to 60 min, and the catalytic degradation reaction temperature is 15℃ to 40℃.

[0018] In this invention, the peroxybicarbonate is prepared by reacting hydrogen peroxide solution with bicarbonate.

[0019] Compared with the prior art, the advantages of the present invention are as follows: (1) This invention provides a method for degrading organic pollutants in water by activating bicarbonate with cobalt-containing zeolite nanosheets. The method uses cobalt-containing zeolite nanosheets as a catalyst to activate bicarbonate and treat organic pollutants in water. The cobalt-containing zeolite nanosheets are prepared by sequentially mixing tetrapropylammonium hydroxide, water, urea, tetraethyl orthosilicate, and cobalt acetylacetonate, followed by hydrothermal reaction and calcination. Zeolite has significant cation exchange capacity and in-situ adsorption capacity, and is stable and inexpensive. In the hydrothermal synthesis of the cobalt-containing zeolite catalyst, the addition of urea inhibits the growth of the b-axis in the zeolite crystals, making the zeolite nanosheets, thereby obtaining more catalytic active sites and higher catalytic activity. Simultaneously, by changing the order of adding Co during the hydrothermal synthesis, the leaching of Co from the cobalt-containing zeolite nanosheets is significantly improved, greatly reducing the risk of secondary pollution. This is because the later addition of Co has less impact on the formation of zeolite crystal nuclei, thus making the Co species more stable in the zeolite. Based on this, when the cobalt-containing zeolite nanosheets are used to activate percarbonate to degrade recalcitrant organic pollutants in water, the increased exposure of the [0 1 0] crystal faces of the cobalt-containing zeolite nanosheets leads to an increase in active sites, effectively activating percarbonate and generating substances such as CO3. - ·OH and ·O2 - as well as 1 This invention utilizes various reactive substances with oxidizing capabilities, such as O2, to achieve efficient degradation of organic pollutants in water. Taking acetaminophen as an example, the method of this invention can achieve 99.0% removal of acetaminophen within 40 minutes, with a Co leaching concentration below 0.092 mg / L (significantly lower than other catalysts in the prior art). It has advantages such as good degradation effect, convenient operation, simple steps, low cost, and environmental friendliness. It is a method suitable for widespread application and capable of efficiently and thoroughly removing organic pollutants from water, with high practical value and promising application prospects.

[0020] (2) Compared with methods for activating other peroxides using cobalt-containing zeolite nanosheets, the peroxybicarbonate oxidation method used in this invention exhibits significantly higher removal efficiency for organic pollutants, exceeding that of common methods such as sodium persulfate and hydrogen peroxide activation by 84.5% and 83.8%, respectively. Furthermore, this invention expands the applicable pH range for treating organic pollutants in water using cobalt-containing zeolite nanosheets. Within an initial pH range of 3.0–9.0, this process demonstrates good oxidative removal effects on organic pollutants (such as acetaminophen) in water, while maintaining the pH at the end of the reaction at approximately 8.6–8.8, overcoming the shortcomings of traditional Fenton reactions, such as narrow pH range and acidification of the effluent. Moreover, due to the buffering effect of bicarbonate, its use avoids the problem of excessive leaching of toxic metal ions, resulting in a total dissolved cobalt ion concentration in the effluent below 0.1 mg / L, significantly lower than the People's Republic of China Surface Water Environmental Quality Standard (1.0 mg / L, GB 3838-2002). Therefore, the method of this invention has broad application prospects in the degradation of environmental pollutants.

[0021] (3) In the method of the present invention, the cobalt-containing zeolite nanosheets used did not show significant deactivation after 5 cycles of experiment, and still maintained high catalytic activity, maintaining a 98.0% removal rate of acetaminophen within 60 min. Furthermore, it can still exhibit high catalytic activity in actual water bodies (tap water, river water, lake water, seawater), and has high practicality. Attached Figure Description

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0023] Figure 1 The images show SEM images of cobalt-containing zeolite nanosheets (Co@MFI) in Example 1 and cobalt-containing zeolite (Co@MFI without urea) in Comparative Example 1, where (a) is Co@MFI and (b) is Co@MFI without urea.

[0024] Figure 2 The images show the XRD patterns of cobalt-containing zeolite nanosheets (Co@MFI) in Example 1 and cobalt-containing zeolite (Co@MFI without urea) in Comparative Example 1.

[0025] Figure 3 EIS images of cobalt-containing zeolite nanosheets (Co@MFI) in Example 1 and cobalt-containing zeolite (Co@MFI without urea) in Comparative Example 1 are shown.

[0026] Figure 4This is a comparison chart showing the degradation effect of acetaminophen in water under different treatment systems in Example 1 and Comparative Examples 1 to 3 of the present invention.

[0027] Figure 5 This is a comparison chart showing the amount of Co ion leaching during the degradation of acetaminophen by cobalt-containing zeolite nanosheets (Co@MFI) prepared in Example 1 of the present invention and cobalt-containing zeolite nanosheets (Co@MFI add Co first) prepared in Comparative Example 4.

[0028] Figure 6 The graph shows the degradation effect of cobalt-containing zeolite nanosheets (Co@MFI) on acetaminophen under different pH conditions.

[0029] Figure 7 This is a diagram showing the degradation effect of cobalt-containing zeolite nanosheets (Co@MFI) on different organic pollutants in Example 3 of the present invention.

[0030] Figure 8 This is a diagram showing the degradation effect of cobalt-containing zeolite nanosheets (Co@MFI) on peroxybicarbonate in different water bodies in Example 4 of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention. All materials and instruments used in the following embodiments are commercially available.

[0032] Example 1: A method for degrading organic pollutants in water by activating peroxybicarbonate with cobalt-containing zeolite nanosheets, specifically involving the degradation treatment of acetaminophen wastewater containing sodium bicarbonate using cobalt-containing zeolite nanosheets and hydrogen peroxide, including the following steps: 105 mg of sodium bicarbonate and 10 mg of cobalt-containing zeolite nanosheets (Co@MFI) were weighed into 50 mL of acetaminophen solution with a concentration of 10 mg / L and pH=5.86. The mixture was magnetically stirred at 400 r / min for 30 min to reach adsorption equilibrium. Then, 1 mol / L hydrogen peroxide solution was added to make the hydrogen peroxide concentration in the system 20 mM. The catalytic degradation reaction was carried out at 25 °C for 60 min to complete the degradation of acetaminophen in the water.

[0033] In this embodiment, the preparation method of cobalt-containing zeolite nanosheets (Co@MFI) includes the following steps: (1) Mix 13.01g of tetrapropylammonium hydroxide, 15.45g of water and 0.96g of urea in a beaker and stir for 2 hours to obtain mixed solution A; (2) 8.32 g of tetraethyl orthosilicate was gradually added to the mixed solution A obtained in step (1) within 1 min, and stirred for 6 h to obtain mixed solution B.

[0034] (3) Add 0.5g of cobalt acetylacetone to the mixed solution B obtained in step (2) and stir for 2h to obtain mixed solution C; (4) The mixed solution C obtained in step (3) is subjected to hydrothermal reaction. The hydrothermal reaction is carried out in a high-pressure reactor at a temperature of 170°C for 72 hours. After the reaction is completed, the product is taken out and cooled. The reaction product is washed with ultrapure water 6 times and then dried in an electric heating drying oven at 100°C for 12 hours.

[0035] (5) The dried product in step (4) is placed in a muffle furnace for calcination at a temperature of 550°C, a heating rate of 2°C / min, and a calcination time of 6h to obtain cobalt-containing zeolite nanosheets, denoted as Co@MFI.

[0036] Comparative Example 1: A method for degrading organic pollutants in water by activating peroxybicarbonate with cobalt-containing zeolite is basically the same as the method in Example 1, except that the catalyst used is cobalt-containing zeolite (Co@MFI without urea).

[0037] In this embodiment, the preparation method of cobalt-containing zeolite (Co@MFI without urea) includes the following steps: (1) Mix 13.01g of tetrapropylammonium hydroxide and 15.45g of water in a beaker and stir for 2 hours to obtain mixed solution A; (2) 8.32 g of tetraethyl orthosilicate was gradually added to the mixed solution A obtained in step (1) within 1 min, and stirred for 6 h to obtain mixed solution B.

[0038] (3) Add 0.5g of cobalt acetylacetone to the mixed solution B obtained in step (2) and stir for 2h to obtain mixed solution C; (4) The mixed solution C obtained in step (3) is subjected to hydrothermal reaction. The hydrothermal reaction is carried out in a high-pressure reactor at a temperature of 170°C for 72 hours. After the reaction is completed, the product is taken out and cooled. The reaction product is washed with ultrapure water 6 times and then dried in an electric heating drying oven at 100°C for 12 hours.

[0039] (5) The dried product from step (4) is placed in a muffle furnace for calcination at a temperature of 550°C, a heating rate of 2°C / min, and a calcination time of 6h to obtain cobalt-containing zeolite, denoted as Co@MFI without urea.

[0040] During the magnetic stirring and degradation process in Example 1 and Comparative Example 1, 1 mL of sample was taken every 10 min and filtered through a 0.22 μm filter. The filtrate was then analyzed by liquid chromatography to determine the concentration of pollutants after adsorption and degradation, thereby obtaining the adsorption effect and catalytic degradation effect of different cobalt-containing zeolite-based catalysts on acetaminophen.

[0041] Figure 1 The images show SEM images of cobalt-containing zeolite nanosheets (Co@MFI) in Example 1 and cobalt-containing zeolite (Co@MFI without urea) in Comparative Example 1, where (a) is Co@MFI and (b) is Co@MFI without urea. Figure 1 It can be seen that both zeolite-based catalysts exhibit typical crystal morphologies of MFI-type zeolites. Compared to Co@MFI without urea, Co@MFI has more exposed active sites, which is beneficial for pollutant adsorption and catalytic degradation.

[0042] Figure 2 The images show the XRD patterns of cobalt-containing zeolite nanosheets (Co@MFI) in Example 1 and cobalt-containing zeolite (Co@MFI without urea) in Comparative Example 1. Figure 2 It can be seen that, after comparing the two zeolite-based catalysts with the MFI-type zeolite PDF standard card, they both conform to the characteristic peaks of typical MFI-type zeolites. This is consistent with the crystal structure of zeolite materials. At 2θ = 8.9º, compared with Co@MFI without urea, the diffraction peak of the cobalt-containing zeolite nanosheets (Co@MFI) in Example 1 has a greater relative intensity, indicating that the diffraction of the zeolite crystal along the [0 1 0] surface gradually increases and more active sites can be exposed.

[0043] Figure 3 The images show the EIS plots of cobalt-containing zeolite nanosheets (Co@MFI) from Example 1 and cobalt-containing zeolite (Co@MFI without urea) from Comparative Example 1. Figure 3 It can be seen that the Co@MFI electrode has a smaller semicircle than the Co@MFI without urea electrode, which confirms that electron transfer at the Co@MFI interface is easier.

[0044] Comparative Example 2: A method for degrading organic pollutants in water by activating hydrogen peroxide with cobalt-containing zeolite nanosheets is basically the same as the method in Example 1, except that in Comparative Example 2, sodium bicarbonate is not added to the acetaminophen solution, and hydrogen peroxide (H2O2) is used as the oxidant.

[0045] Comparative Example 3: A method for degrading organic pollutants in water by activating persulfate with cobalt-containing zeolite nanosheets is basically the same as the method in Example 1, except that in Comparative Example 3, sodium bicarbonate and hydrogen peroxide are not added to the acetaminophen solution, and sodium persulfate (PS) is used as the oxidant.

[0046] During the magnetic stirring and degradation process of Comparative Examples 2 and 3, 1 mL of sample was taken every 10 min and filtered with a 0.22 μm filter. The filtrate was then analyzed by liquid chromatography to determine the concentration of pollutants after adsorption and degradation. This yielded the adsorption and catalytic degradation effects of cobalt-containing zeolite nanosheet catalyst on different oxidation systems.

[0047] Figure 4 This is a comparison chart showing the degradation effects of different treatment systems on acetaminophen in water in Examples 1, 1, 2, and 3 of the present invention. Figure 4 It can be seen that after 30 min of adsorption and 40 min of oxidative degradation, the removal rates of acetaminophen by Co@MFI and Co@MFI withouturea through activation of percarbonate (PMC) were 99.9% and 71.6%, respectively. This is because the [0 1 0] crystal facets of Co@MFI are exposed, resulting in more catalytic active sites and easier electron transfer. Therefore, this invention ultimately selected Co@MFI as a catalyst to activate percarbonate for the treatment of water containing acetaminophen.

[0048] At the same time, by Figure 4 It was found that when H2O2 and PS were activated using Co@MFI, the removal rates of acetaminophen after 30 min of adsorption and 60 min of oxidative degradation were 15.2% and 14.5%, respectively, significantly lower than the degradation effect of peroxybicarbonate activated by Co@MFI (100%). This is attributed to the fact that when peroxybicarbonate is activated by Co@MFI, the generated ·OH combines with bicarbonate ions, forming a more complex oxidation mechanism that generates ·CO3. - , O2 - and 1 O2 and other active oxygen species. In addition, using percarbonate as an oxidant can effectively avoid the leaching of excessive cobalt ions and maintain the pH value of the treated effluent at neutral. Therefore, in this invention, percarbonate was ultimately chosen as the oxidant to synergistically treat water containing acetaminophen using Co@MFI.

[0049] Comparative Example 4: A method for degrading organic pollutants in water by activating peroxybicarbonate using cobalt-containing zeolite nanosheets is basically the same as the method in Example 1, except that in Comparative Example 4, the catalyst used is cobalt-containing zeolite nanosheets with cobalt added first during preparation (Co@MFI add Co first).

[0050] In Comparative Example 4, the preparation method of cobalt-containing zeolite nanosheets (Co@MFI add Co first) includes the following steps: (1) Add 13.01g tetrapropylammonium hydroxide, 15.45g water, 8.32g tetraethyl orthosilicate, 0.96g urea and 0.5g cobalt acetylacetonate to a beaker and stir for 10h to obtain a mixed solution.

[0051] (2) Pour the mixed solution from step (1) into a high-pressure reactor and heat it at 170°C for 72 hours. After the reaction is completed, remove it and cool it. Wash the reaction product with ultrapure water 6 times and then dry it at 100°C for 12 hours in an electric heating drying oven.

[0052] (3) The dried product in step (2) is placed in a muffle furnace for calcination at a temperature of 550°C, a heating rate of 2°C / min, and a calcination time of 6h to obtain cobalt-containing zeolite nanosheets, denoted as Co@MFI add Co first.

[0053] In Example 1 and Comparative Example 4, during the magnetic stirring and degradation process, 2 mL of sample was taken every 10 min and filtered through a 0.22 μm filter. 1 mL of the filtrate was then placed in a 10 mL centrifuge tube, and 5 mL of ultrapure water was added. After mixing, the concentration of Co ions leached during the degradation process was determined by inductively coupled plasma mass spectrometry (ICP-MS), thus revealing the effect of the order in which Co-containing reagents were added during hydrothermal synthesis on the amount of Co leached from cobalt-containing zeolite nanosheets.

[0054] Figure 5 This is a comparison chart showing the amount of Co ion leaching during the degradation of acetaminophen by cobalt-containing zeolite nanosheets (Co@MFI) prepared in Example 1 of this invention and cobalt-containing zeolite nanosheets (Co@MFI add Co first) prepared in Comparative Example 4. Figure 5 It can be seen that, under the same conditions, the amount of Co ions leached by Co@MFI is significantly less than that by Co@MFI add Co first. This confirms that the timing of adding the Co-containing reagent has a significant impact on the amount of Co ions leached from the prepared cobalt-containing zeolite nanosheets during use. Adding the Co-containing reagent cobalt acetylacetone later helps to significantly reduce the amount of Co ions leached from the prepared cobalt-containing zeolite nanosheet catalyst. The Co leaching concentration is less than 0.092 mg / L within 40 min, thereby reducing secondary pollution and making it more environmentally friendly.

[0055] Example 2: A method for degrading organic pollutants in water by activating peroxybicarbonate with cobalt-containing zeolite nanosheets, specifically involving the degradation treatment of acetaminophen wastewater containing sodium bicarbonate at different pH values ​​using cobalt-containing zeolite nanosheets and hydrogen peroxide, including the following steps: Four 105 mg portions of sodium bicarbonate and four 10 mg portions of cobalt-containing zeolite nanosheets (Co@MFI) prepared in Example 1 were weighed and added to acetaminophen solutions with pH values ​​of 3, 5, 7, and 9 (the solution volume was 50 mL and the concentration was 10 mg / L). The mixture was magnetically stirred at 400 r / min for 30 min to reach adsorption equilibrium. Then, a 1 mol / L hydrogen peroxide solution was added to make the hydrogen peroxide concentration in the system 20 mM. The degradation reaction was carried out at 25 °C for 60 min to complete the degradation of acetaminophen in the water.

[0056] During magnetic stirring and degradation, 1 mL of sample was taken every 10 min and filtered through a 0.22 μm filter. The filtrate was then analyzed by liquid chromatography to determine the concentration of pollutants after adsorption and degradation. This allowed for the determination of the adsorption and catalytic degradation effects of cobalt-containing zeolite-based catalysts on acetaminophen under different pH conditions.

[0057] Figure 6 This image shows the degradation effect of cobalt-containing zeolite nanosheets (Co@MFI) on acetaminophen under different pH conditions in Example 2 of this invention. Figure 6 It can be seen that the cobalt-containing zeolite nanosheets (Co@MFI) of the present invention achieve a 100% removal rate of acetaminophen at pH values ​​of 3, 5, 7, and 9, indicating that the method of the present invention has a wide pH range of applicability. Simultaneously, maintaining the pH value at approximately 8.6–8.8 at the end of the reaction ensures that the reaction medium remains in a neutral to alkaline environment, overcoming the shortcomings of traditional Fenton reactions such as narrow pH range and acidification of effluent.

[0058] Example 3: A method for degrading organic pollutants in water by activating peroxybicarbonate with cobalt-containing zeolite nanosheets, specifically, involves using cobalt-containing zeolite nanosheets and hydrogen peroxide to degrade wastewater containing sodium bicarbonate, acetaminophen, sulfamethoxazole, tetracycline hydrochloride, and bisphenol A, respectively, including the following steps: Four 105 mg portions of sodium bicarbonate and three 10 mg portions of cobalt-containing zeolite nanosheets (Co@MFI) prepared in Example 1 were weighed and added to acetaminophen (ACE) solution, sulfamethoxazole (SMX) solution, tetracycline hydrochloride (TC) solution, and bisphenol A (BPA) solution (the volume of these solutions was 50 mL and the concentration was 10 mg / L). The mixture was magnetically stirred at 400 r / min for 30 min to reach adsorption equilibrium. Then, a 1 mol / L hydrogen peroxide solution was added to make the hydrogen peroxide concentration in the system 20 mM. The degradation reaction was carried out at 25 °C for 60 min to complete the degradation of various organic pollutants in the water.

[0059] During magnetic stirring and degradation, 1 mL of sample was taken every 10 min and filtered with a 0.22 μm filter. The filtrate was then analyzed by liquid chromatography to determine the concentration of pollutants after adsorption and degradation, thereby obtaining the adsorption effect and catalytic degradation effect of the cobalt-containing zeolite nanosheet catalyst of the present invention on various organic pollutants.

[0060] Figure 7 This image shows the degradation effect of cobalt-containing zeolite nanosheets (Co@MFI) activated percarbonate on different organic pollutants in Example 3 of this invention. The test results show that after 60 minutes of degradation reaction, the removal rates of acetaminophen (ACE) solution, sulfamethoxazole (SMX) solution, tetracycline hydrochloride (TC) solution, and bisphenol A (BPA) solution by cobalt-containing zeolite nanosheets (Co@MFI) reached 100%, 92.9%, 100%, and 90.1%, respectively. Therefore, the cobalt-containing zeolite nanosheets (Co@MFI) activated percarbonate of this invention exhibits excellent degradation effects on various organic pollutants.

[0061] Example 4: A method for degrading organic pollutants in water by activating peroxybicarbonate using cobalt-containing zeolite nanosheets, specifically involving the degradation of acetaminophen in different water bodies containing sodium bicarbonate using cobalt-containing zeolite nanosheets and hydrogen peroxide, including the following steps: Four portions of acetaminophen, each 10 mg, were weighed and dissolved in filtered seawater, lake water, tap water, river water, and deionized water, respectively, to prepare an initial concentration of 10 mg / L and a volume of 50 mL. These were placed in 100 mL beakers, and 105 mg of sodium bicarbonate and 10 mg of cobalt-containing zeolite nanosheets (Co@MFI) prepared in Example 1 were added to each beaker. The mixture was magnetically stirred at 400 r / min for 30 min until adsorption equilibrium was reached. Then, a 1 mol / L hydrogen peroxide solution was added to bring the hydrogen peroxide concentration in the system to 20 mM. The degradation reaction was carried out at 25 °C for 60 min to complete the degradation of acetaminophen in the water.

[0062] During magnetic stirring and degradation, 1 mL of sample was taken every 10 min and filtered with a 0.22 μm filter. The filtrate was then analyzed by liquid chromatography to determine the concentration of pollutants after adsorption and degradation, thereby obtaining the adsorption effect and catalytic degradation effect of the cobalt-containing zeolite nanosheet catalyst of the present invention on acetaminophen in different water bodies.

[0063] Figure 8 This image shows the degradation effect of cobalt-containing zeolite nanosheets (Co@MFI) on peroxybicarbonate in different water bodies, as described in Example 4 of this invention. Figure 8 It can be seen that the removal rates of acetaminophen by the cobalt-containing zeolite nanosheets (Co@MFI) of the present invention in seawater, lake water, tap water, river water, and deionized water are 78.8%, 90.4%, 78.7%, 93.7%, and 100%, respectively. Therefore, the cobalt-containing zeolite nanosheets (Co@MFI) of the present invention perform well in actual water bodies, and acetaminophen in different actual water bodies can be effectively degraded.

[0064] The results above show that the cobalt-containing zeolite nanosheets (Co@MFI) prepared in this invention can efficiently activate peroxybicarbonate to degrade recalcitrant organic pollutants in water. Specifically, during the hydrothermal synthesis of the cobalt-containing zeolite catalyst, the addition of urea can inhibit the growth of the b-axis in the zeolite crystals, causing the zeolite to form nanosheets. This results in a catalyst with more catalytic active sites and higher catalytic activity. Due to the exposure of the [0 1 0] crystal faces of the cobalt-containing zeolite nanosheets, the number of active sites increases, effectively activating peroxybicarbonate and generating substances such as CO3. - ·OH and ·O2 - as well as 1 This invention utilizes various reactive substances with oxidizing capabilities, such as O2, to achieve highly efficient degradation of organic pollutants in water. Taking acetaminophen as an example, the method of this invention can remove 99.0% of acetaminophen within 40 minutes, demonstrating a significant degradation effect. More importantly, by controlling the timing of the addition of the Co-containing reagent, this invention can significantly reduce the leaching of Co ions from the prepared cobalt-containing zeolite nanosheets. This allows the cobalt-containing zeolite nanosheets of this invention to simultaneously possess advantages such as good degradation effect on organic pollutants, convenient operation, simple steps, low cost, environmental friendliness, and wide pH applicability. It is a method suitable for widespread application and capable of efficiently and thoroughly removing organic pollutants from water, with high practical value and promising application prospects.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for degrading organic pollutants in water bodies using cobalt-containing zeolite nanosheets to activate peroxycarbonate, characterized in that, Cobalt-containing zeolite nanosheets are used as a catalyst to activate peroxybicarbonate for the degradation of organic pollutant wastewater. The cobalt-containing zeolite nanosheets are prepared by sequentially mixing tetrapropylammonium hydroxide, water, urea, tetraethyl orthosilicate, and cobalt acetylacetonate, followed by hydrothermal reaction and calcination. The mass ratio of tetrapropylammonium hydroxide, urea, tetraethyl orthosilicate, cobalt acetylacetonate, and water is 13.01:0.96:8.32:0.5:15.

45. The preparation steps of the cobalt-containing zeolite nanosheets include: S1. Mix tetrapropylammonium hydroxide, water and urea, and stir to obtain mixed solution A; S2. Add tetraethyl orthosilicate to the mixed solution A and stir to obtain mixed solution B; S3. Add cobalt acetylacetone to the mixed solution B and stir to obtain mixed solution C; S4. A hydrothermal reaction is carried out on the mixed solution C, wherein the reaction temperature of the hydrothermal reaction is 150℃~180℃ and the reaction time is 70h~96h. S5. The product of the hydrothermal reaction is calcined to obtain cobalt-containing zeolite nanosheets; the calcination temperature is 500℃~600℃, the calcination heating rate is 1℃ / min~5℃ / min, and the calcination time is 4h~8h.

2. The method for degrading organic pollutants in water bodies by using cobalt-containing zeolite nanosheets to activate peroxycarbonate salt according to claim 1, characterized in that, In step S1, the stirring time is 1 hour to 3 hours; In step S2, the stirring time is 5h to 8h; In step S3, the stirring time is 1 hour to 3 hours.

3. The method of claim 1, wherein the method is characterized by, In step S4, the hydrothermal reaction includes the following treatment: washing and drying the reaction product; the washing is performed by washing with water 5 to 8 times, the drying temperature is 80℃ to 105℃, and the drying time is 10h to 14h.

4. The method for degrading organic pollutants in water body by using cobalt-containing zeolite nanosheets to activate peroxycarbonate salt according to any one of claims 1-3, characterized in that, The degradation process involves mixing bicarbonate, cobalt-containing zeolite nanosheets, and organic pollutant wastewater, then adding hydrogen peroxide solution to carry out a catalytic degradation reaction.

5. The method for degrading organic pollutants in water bodies by using cobalt-containing zeolite nanosheets to activate peroxycarbonate salt according to claim 4, characterized in that, The concentration of bicarbonate in the organic pollutant wastewater is 5 mmol / L to 50 mmol / L, the concentration of hydrogen peroxide in the organic pollutant wastewater is 10 mmol / L to 100 mmol / L, and the concentration of cobalt-containing zeolite nanosheets in the organic pollutant wastewater is 0.1 g / L to 0.6 g / L; the initial concentration of organic pollutants in the organic pollutant wastewater is ≤10 mg / L; and the initial concentration of the hydrogen peroxide solution is 1 mol / L.

6. The method for degrading organic pollutants in water using cobalt-containing zeolite nanosheets activated with percarbonate according to claim 5, characterized in that, The bicarbonate is sodium bicarbonate and / or potassium bicarbonate; the organic pollutant in the organic pollutant wastewater is at least one of acetaminophen, sulfamethoxazole, tetracycline hydrochloride, and bisphenol A.

7. The method for degrading organic pollutants in water using cobalt-containing zeolite nanosheets activated with percarbonate according to claim 6, characterized in that, The mixing process of bicarbonate, cobalt-containing zeolite nanosheets, and organic pollutant wastewater is carried out under stirring conditions. The stirring speed is 300 r / min to 400 r / min, the stirring time is 30 min to 60 min, the catalytic degradation reaction time is 40 min to 60 min, and the catalytic degradation reaction temperature is 15℃ to 40℃.

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