Preparation method and application of MnO-CoMn2O4 catalyst for activating persulfate to treat organic wastewater
By preparing MnO@CoMn2O4 catalyst and using its sea urchin-like structure to activate persulfate, the treatment problem of difficult-to-degrade organic pollutants was solved, and efficient and low-cost degradation of organic pollutants was achieved.
Patent Information
- Application Number
- CN202510474825.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2025-09-12
AI Technical Summary
Existing technologies are unable to effectively treat refractory organic pollutants such as endocrine-disrupting chemicals and pharmaceuticals. Traditional methods are inefficient and costly, especially for toxic and persistent organic pollutants.
The MnO@CoMn2O4 catalyst was used to form a sea urchin-like structure through hydrothermal and calcination treatment, which activated persulfate to produce strong oxidants, sulfate radicals and hydroxyl radicals, and degraded organic pollutants.
It achieves efficient and rapid degradation of organic pollutants, is simple to operate, low-cost, has a wide range of adaptability, and can effectively treat phenolic pollutants in the presence of various anions with significant degradation effects.
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Figure CN120618480A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of material preparation and environmental catalysis, and in particular to a method for preparing a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater and its application. Background Art
[0002] Over the past few decades, due to the continuous development of industrialization, urbanization, and commercialization, an increasing number of organic pollutants have been discharged into the aquatic environment. These emerging pollutants pose a significant threat to human health and ecosystem safety, especially those that are toxic, persistent, or biodegradable, and difficult to treat using traditional methods. These pollutants, such as endocrine-disrupting chemicals, pharmaceuticals, personal care products, and other persistent organic pollutants, must be strictly treated before discharge.
[0003] Advanced oxidation processes (AOPs) have become effective methods for removing refractory organic matter from water bodies due to their high reactivity and oxidative capacity for a wide range of pollutants. AOPs offer advantages such as high efficiency, rapid rates, strong treatment capacity, and wide applicability. Extensive research has been conducted on various high-efficiency AOPs, including Fenton oxidation, electrochemical oxidation, photocatalytic oxidation, and persulfate AOPs. Sulfate radicals generated by persulfate offer advantages such as high oxidation potential, wide pH range, long half-life, and preferential reaction with unsaturated bonds or benzene rings. To generate strong oxidants, sulfate radicals, and hydroxyl radicals, persulfate must be properly activated. Previous studies have proposed various activation methods, including alkalinity, heat, ultraviolet light, ultrasound, electrochemistry, and metal-based materials. Metal-based catalysts for persulfate activation have garnered increasing attention due to their cost-effectiveness, low energy consumption, ease of scalability, and applicability in both homogeneous and heterogeneous systems. Summary of the Invention
[0004] The object of the present invention is to provide a method for preparing a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater and its application, so as to solve the problems raised in the above background technology.
[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater, comprising the following steps:
[0006] S1. Dissolve cobalt nitrate hexahydrate, urea, and ammonium fluoride in deionized water and stir continuously to form a homogeneous solution;
[0007] S2. Transferring the homogeneous solution obtained in step S1 to a stainless steel autoclave, subjecting it to a hydrothermal reaction, cooling, filtering, and washing to obtain a cobalt-containing precursor;
[0008] S3, dissolving the cobalt-containing precursor prepared in step S2, manganese chloride tetrahydrate, and anhydrous sodium sulfate in deionized water, stirring continuously in a water bath, and finally forming a precipitate;
[0009] S4, washing the precipitate obtained in step S3 with deionized water and anhydrous ethanol three times each;
[0010] S5. calcining the precipitate obtained in step S3 under air atmosphere to obtain a MnO@CoMn2O4 catalyst.
[0011] Preferably, in step S1:
[0012] The mass ratio of cobalt nitrate hexahydrate, urea and ammonium fluoride is 3:3:1;
[0013] The stirring time is 30 to 45 minutes.
[0014] Preferably, in step S2: the temperature of the hydrothermal reaction is 120° C.; the hydrothermal reaction time is 5 h; the precipitate obtained after filtration needs to be further washed, and the washing liquids used are water and ethanol respectively; the number of washing times is 2 to 3 times.
[0015] Preferably, in step S3, the mass ratio of the cobalt-containing precursor, manganese chloride tetrahydrate and anhydrous sodium sulfate is 2:7:10; the water bath temperature is controlled at 90° C.; and the stirring time is 60 min.
[0016] Preferably, in step S5, the heating rate during the calcination process is 3°C / min; the calcination temperature is 200°C; and the calcination time is 3 hours.
[0017] The invention discloses an application of a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater, comprising the following steps: mixing a persulfate solution with organic wastewater, adding the MnO@CoMn2O4 catalyst, and performing a catalytic oxidation reaction to complete the degradation of organic pollutants in the water.
[0018] Preferably, the persulfate is potassium hydrogen persulfate, and the addition amount is 0.4 mmol / L.
[0019] Preferably, the organic wastewater is wastewater containing at least one of para-chlorophenol, bisphenol A and phenol as organic pollutants; the concentration of the pollutants is 7.5 mg / L.
[0020] Preferably, the addition amount of the MnO@CoMn2O4 catalyst is 25 mg / L.
[0021] Preferably, the catalytic oxidation reaction is carried out at a stirring speed of 200-400 rpm; and the catalytic oxidation reaction time is 20 min.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] 1. Using cobalt nitrate hexahydrate and manganese chloride tetrahydrate as main raw materials, after a series of hydrothermal and calcination treatments, a sea urchin-shaped catalyst is formed. This hybrid catalyst has multiple reactive sites and can efficiently and rapidly activate persulfate to degrade organic pollutants. The present invention is simple to operate and low in cost. The prepared catalyst has a novel structure and high catalytic efficiency, which can meet actual needs and has broad prospects in the field of persulfate activation.
[0024] 2. The present invention also provides an application of a MnO@CoMn2O4 catalyst in treating phenolic wastewater. Specifically, the MnO@CoMn2O4 catalyst is used to activate persulfate to degrade phenolic pollutants in water. By mixing the MnO@CoMn2O4 catalyst with organic pollutant wastewater, stirring, and adding persulfate, effective degradation of organic pollutants can be achieved. The method has the advantages of simple process, convenient operation, high treatment efficiency, and good degradation effect, and has a good degradation effect in the presence of various anions. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 This is the XRD pattern of the MnO@CoMn2O4 catalyst prepared in Example 1 of the present invention;
[0026] Figure 2 、 3 This is a SEM image of the MnO@CoMn2O4 catalyst prepared in Example 1 of the present invention;
[0027] Figure 4 This is a time-degradation efficiency diagram corresponding to the degradation of phenol solution by persulfate activated by MnO@CoMn2O4 catalyst in Example 2 of the present invention;
[0028] Figure 5 This is a time-degradation efficiency diagram corresponding to the degradation of phenol solution by activating persulfate with different addition amounts of MnO@CoMn2O4 catalyst in Example 2 of the present invention;
[0029] Figure 6 This is a time-degradation efficiency diagram corresponding to the MnO@CoMn2O4 catalyst in Example 2 of the present invention when activating persulfate to degrade phenol solution at different PMS addition amounts;
[0030] Figure 7This is the corresponding time-degradation efficiency diagram of the degradation of phenol solution by persulfate activated by MnO@CoMn2O4 catalyst in the presence of different anions in Example 3 of the present invention. DETAILED DESCRIPTION
[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0032] See also Figure 1-7 The present invention provides a technical solution: a method for preparing a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater, comprising the following steps:
[0033] S1. Dissolve cobalt nitrate hexahydrate, urea, and ammonium fluoride in deionized water and stir continuously to form a homogeneous solution;
[0034] S2. Transferring the homogeneous solution obtained in step S1 to a stainless steel autoclave, subjecting it to a hydrothermal reaction, cooling, filtering, and washing to obtain a cobalt-containing precursor;
[0035] S3, dissolving the cobalt-containing precursor prepared in step S2, manganese chloride tetrahydrate, and anhydrous sodium sulfate in deionized water, stirring continuously in a water bath, and finally forming a precipitate;
[0036] S4, washing the precipitate obtained in step S3 with deionized water and anhydrous ethanol three times each;
[0037] S5. calcining the precipitate obtained in step S3 under air atmosphere to obtain a MnO@CoMn2O4 catalyst.
[0038] In the present invention, in step S1:
[0039] The mass ratio of cobalt nitrate hexahydrate, urea and ammonium fluoride is 3:3:1;
[0040] The stirring time is 30 to 45 minutes.
[0041] In the present invention, in step S2: the temperature of the hydrothermal reaction is 120° C.; the hydrothermal reaction time is 5 hours; the precipitate obtained after filtration needs to be further washed, and the washing liquids used are water and ethanol respectively; the washing times are 2 to 3 times.
[0042] In the present invention, in step S3, the mass ratio of the cobalt-containing precursor, manganese chloride tetrahydrate and anhydrous sodium sulfate is 2:7:10; the water bath temperature is controlled at 90° C.; and the stirring time is 60 min.
[0043] In the present invention, in step S5, the heating rate during the calcination process is 3°C / min; the calcination temperature is 200°C; and the calcination time is 3 hours.
[0044] The invention discloses an application of a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater, comprising the following steps: mixing a persulfate solution with organic wastewater, adding the MnO@CoMn2O4 catalyst, and performing a catalytic oxidation reaction to complete the degradation of organic pollutants in the water.
[0045] In the present invention, the persulfate is potassium hydrogen persulfate, and the addition amount is 0.4 mmol / L.
[0046] In the present invention, the organic wastewater is wastewater containing at least one of p-chlorophenol, bisphenol A and phenol as organic pollutants; the concentration of the pollutants is 7.5 mg / L.
[0047] In the present invention, the addition amount of the MnO@CoMn2O4 catalyst is 25 mg / L.
[0048] In the present invention, the catalytic oxidation reaction is carried out at a stirring speed of 200-400 rpm; the catalytic oxidation reaction time is 20 minutes.
[0049] In the following examples of the present invention, unless otherwise specified, the materials and instruments used are commercially available, the processes used are conventional processes, the equipment used are conventional equipment, and the data obtained are the average values of three or more repeated experiments.
[0050] Example 1:
[0051] A method for preparing a MnO@CoMn2O4 catalyst is prepared using cobalt nitrate hexahydrate and manganese chloride tetrahydrate as main raw materials, comprising the following steps:
[0052] 0.291 g of cobalt nitrate hexahydrate, 0.300 g of urea, and 0.111 g of ammonium fluoride were dissolved in deionized water to form a mixed solution. Subsequently, the mixed solution was stirred for 30 min to form a homogeneous solution, and then transferred to a Teflon-lined stainless steel autoclave and maintained at 120°C for 5 h. After the product was cooled to room temperature, it was centrifuged and washed three times with deionized water and ethanol. The sample was dried at 60°C for 12 h to obtain a cobalt-containing precursor. 0.2 g of the cobalt-containing precursor, 0.7 g of manganese chloride tetrahydrate, and 1 g of anhydrous manganese sulfate were dissolved in water and stirred continuously at 90°C to form a precipitate. The obtained precipitate was washed three times with deionized water and ethanol respectively. After drying at 60°C for 12 h, it was annealed in air by increasing the heating rate by 3°C / min and maintained at 200°C for 3 h. Then, the sample was naturally cooled to obtain the MnO@CoMn2O4 catalyst.
[0053] Figure 1 The XRD pattern of the MnO@CoMn2O4 catalyst prepared in Example 1 of the present invention is shown in FIG. Figure 1 It can be found that there are three obvious XRD diffraction peaks at 17.3°, 26.6° and 36.3°, which are attributed to the MnO (020), (120) and (021) crystal planes, and there are three obvious XRD diffraction peaks at 33.5°, 36.2° and 39.8°, which are attributed to the CoMn2O4 (103), (211) and (004) crystal planes, confirming that the prepared product is MnO@CoMn2O4.
[0054] Figure 2 、 3 The SEM image of the MnO@CoMn2O4 catalyst prepared in Example 1 of the present invention; Figure 2 It can be seen that the MnO@CoMn2O4 catalyst is sea urchin-shaped, and the Mn and Co elements are evenly distributed in the material; Figure 3 It can be seen that the diameter of each nanorod is about 225.00 nm.
[0055] Example 2:
[0056] An application of a MnO@CoMn2O4 catalyst in treating phenolic wastewater, specifically using the MnO@CoMn2O4 catalyst to activate persulfate to degrade phenolic pollutants in water, comprising the following steps:
[0057] 2.5 mg of the MnO@CoMn2O4 catalyst prepared in Example 1 was weighed and placed in 100 mL of a 7.5 mg / L phenol solution. Then, 0.4 mL of a 100 mmol / L PMS solution was added to the solution. The MnO@CoMn2O4 catalyst was used to activate persulfate to degrade phenol in the water, thereby completing the degradation of phenol in the water.
[0058] During the persulfate activation reaction, 1 ml of phenol solution was collected at time points of 0 min, 3 min, 6 min, 9 min, 12 min, 15 min, and 18 min. The characteristic peak of phenol in the solution was measured by liquid chromatography, and the degradation efficiency of the catalyst on the phenol solution under different time conditions was calculated.
[0059] Figure 4 This is a time-degradation efficiency diagram corresponding to the activation of persulfate by the MnO@CoMn2O4 catalyst in Example 2 of the present invention to degrade phenol solution; Figure 4 As shown in the figure, after 18 min of reaction, the degradation efficiency of phenol by MnO@CoMn2O4 catalyst reached 100%.
[0060] In this example, the effects of different MnO@CoMn2O4 catalyst addition amounts and different persulfate addition amounts on the phenol degradation effect were also investigated.
[0061] Figure 5 This is a time-degradation efficiency diagram corresponding to the degradation of phenol solution by activating persulfate with different addition amounts of MnO@CoMn2O4 catalyst in Example 2 of the present invention; Figure 6 : This is a time-degradation efficiency diagram corresponding to the activation of persulfate and degradation of phenol solution by the MnO@CoMn2O4 catalyst in Example 2 of the present invention at different PMS addition amounts; Figure 5 and Figure 6 It can be seen that the reaction rate gradually increases with the increase of catalyst or persulfate addition, which indicates that the MnO@CoMn2O4 catalyst has good persulfate activation performance, and more catalyst or PMS addition can lead to more effective degradation reaction.
[0062] Example 3:
[0063] An application of a MnO@CoMn2O4 catalyst in treating phenolic wastewater, specifically using the MnO@CoMn2O4 catalyst to activate persulfate to degrade phenolic pollutants in water, comprising the following steps:
[0064] 2.5 mg of the MnO@CoMn2O4 catalyst prepared in Example 1 was weighed and placed in 100 mL of a 7.5 mg / L phenol solution. Then, 0.4 mL of a 100 mmol / L PMS solution was added to the solution, and different anions of equal concentrations were added. The MnO@CoMn2O4 catalyst was used to activate persulfate to degrade phenol in the water, thereby completing the degradation of phenol in the water.
[0065] During the persulfate activation reaction, 1 ml of phenol solution was collected at time points of 0 min, 3 min, 6 min, 9 min, 12 min, 15 min, and 18 min. The characteristic peak of phenol in the solution was measured by liquid chromatography, and the degradation efficiency of the catalyst on the phenol solution under different time conditions was calculated.
[0066] Figure 7 The corresponding time-degradation efficiency diagram of the MnO@CoMn2O4 catalyst activated persulfate to degrade phenol solution in the presence of different anions in Example 3 of the present invention; Figure 7 It can be seen that the presence of anions does not affect the degradation of phenol by MnO@CoMn2O4 catalyst, and the MnO@CoMn2O4 catalyst has anti-interference ability.
[0067] In summary, the present invention provides a method for preparing a MnO@CoMn2O4 catalyst, which uses cobalt nitrate hexahydrate and manganese chloride tetrahydrate as main raw materials. After a series of hydrothermal and calcination treatments, a sea urchin-shaped catalyst is formed. This mixed catalyst has multiple reactive sites and can achieve efficient and rapid activation of persulfate to degrade organic pollutants. The present invention is simple to operate and low in cost. The prepared catalyst has a novel structure and high catalytic efficiency, which can meet actual needs and has broad prospects in the field of persulfate activation.
[0068] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field. Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater, characterized in that: The following steps are involved: S1. Dissolve cobalt nitrate hexahydrate, urea, and ammonium fluoride in deionized water and stir continuously to form a homogeneous solution; S2. Transferring the homogeneous solution obtained in step S1 to a stainless steel autoclave, subjecting it to a hydrothermal reaction, cooling, filtering, and washing to obtain a cobalt-containing precursor; S3, dissolving the cobalt-containing precursor prepared in step S2, manganese chloride tetrahydrate, and anhydrous sodium sulfate in deionized water, stirring continuously in a water bath, and finally forming a precipitate; S4, washing the precipitate obtained in step S3 with deionized water and anhydrous ethanol three times each; S5. calcining the precipitate obtained in step S3 under air atmosphere to obtain a MnO@CoMn2O4 catalyst.
2. The method for preparing a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater according to claim 1, characterized in that: In the step S1: The mass ratio of cobalt nitrate hexahydrate, urea and ammonium fluoride is 3:3:1; The stirring time is 30 to 45 minutes.
3. The method for preparing a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater according to claim 1, characterized in that: In step S2, the temperature of the hydrothermal reaction is 120° C.; the hydrothermal reaction time is 5 hours; the precipitate obtained after filtration needs to be further washed, and the washing liquids used are water and ethanol respectively; the washing times are 2 to 3 times.
4. The method for preparing a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater according to claim 1, characterized in that: In step S3, the mass ratio of the cobalt-containing precursor, manganese chloride tetrahydrate, and anhydrous sodium sulfate is 2:7:10; the water bath temperature is controlled at 90° C.; and the stirring time is 60 minutes.
5. The method for preparing a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater according to claim 1, characterized in that: In step S5, the heating rate during the calcination process is 3°C / min; the calcination temperature is 200°C; and the calcination time is 3 hours.
6. Use of a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater according to claims 1-5, characterized in that: The following steps are involved: The persulfate solution is mixed with organic wastewater, and MnO@CoMn2O4 catalyst is added to carry out catalytic oxidation reaction to complete the degradation of organic pollutants in the water.
7. The use of a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater according to claim 6, characterized in that: The persulfate is potassium hydrogen persulfate, and the added amount is 0.4 mmol / L.
8. The use of a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater according to claim 6, characterized in that: The organic wastewater is wastewater containing at least one of the organic pollutants p-chlorophenol, bisphenol A, and phenol; the concentration of the pollutants is 7.5 mg / L.
9. The use of a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater according to claim 6, characterized in that: The addition amount of the MnO@CoMn2O4 catalyst is 25 mg / L.
10. The use of a MnO@CoMn2O4 catalyst for activating persulfate to treat organic wastewater according to claim 6, characterized in that: The catalytic oxidation reaction is carried out at a stirring speed of 200-400 rpm; the catalytic oxidation reaction time is 20 minutes.