A FeCu@NC Fenton-type catalyst and its preparation method and application

Abstract

The present invention discloses a FeCu@N-C type Fenton catalyst and its preparation method and application, which belongs to the field of catalyst technology. The preparation method of the catalyst comprises the following steps: dissolving a water-soluble iron salt, a water-soluble copper salt, a carbon source and urea in water to obtain a mixed solution; removing the moisture in the mixed solution to obtain a solid; grinding and mixing the solid with a zinc carbonate to obtain a mixed powder; calcining the mixed powder in a protective atmosphere to obtain a FeCu@N-C type Fenton catalyst. The raw materials used in the present invention are cheap and easy to obtain, the operation method is simple, and the synthesis is convenient. The prepared FeCu@N-C type Fenton catalyst can be applied to heterogeneous Fenton oxidation reactions to efficiently degrade organic pollutants. Since the catalyst is simple to prepare and easy to industrialize, it has high efficiency in the degradation of pollutants and has extremely high application value in the treatment of organic pollutant wastewater.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and in particular relates to a FeCu@NC Fenton-type catalyst and a preparation method and application thereof. Background Art

[0002] Water pollution poses a significant threat to human health and aquatic ecosystems. The biological oxidation and decomposition of organic pollutants in water requires significant amounts of dissolved oxygen. Once the oxygen supply in the water is insufficient, oxidation ceases, leading to anaerobic fermentation of the organic matter, which emits foul odors, pollutes the environment, and harms aquatic life. Therefore, the development and implementation of wastewater treatment technologies are crucial for eliminating pollutants.

[0003] Currently, advanced oxidation processes (AOPs) using activated hydrogen peroxide have attracted continuous attention due to their high oxidation efficiency and simple operation. This process requires external energy input to cleave the peroxide bond. Several physical methods such as ultraviolet irradiation, heating and ultrasound have been shown to be effective in activating hydrogen peroxide, but this significantly increases the operating cost. Heterogeneous catalysts for hydrogen peroxide activation have attracted much attention due to their ease of operation and versatility. Hydrogen peroxide can be activated to generate various reactive oxygen species, such as hydroxyl radicals, superoxide radicals and singlet oxygen, which degrade pollutants through free radical and non-radical pathways. Currently, some catalysts have been used to activate hydrogen peroxide to degrade organic pollutants in wastewater. However, they generally have disadvantages such as poor stability, high cost and easy poisoning, which seriously hinder their large-scale industrial application. Therefore, the development of efficient and durable heterogeneous hydrogen peroxide catalysts is urgent. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the purpose of the present invention is to provide a FeCu@NC Fenton-type catalyst and its preparation method and application. By confining Fe and Cu in N-doped porous carbon materials, the strong binding of carbon and FeCu can change its electronic structure, which is conducive to adsorption and reduces the binding energy barrier, thereby significantly improving the catalytic performance.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] The present invention provides a method for preparing a FeCu@NC-type Fenton catalyst, comprising the following steps:

[0007] (1) Dissolving a water-soluble iron salt, a water-soluble copper salt, a carbon source, and urea in water to obtain a mixed solution; preferably, the water-soluble iron salt is ferric nitrate or ferric chloride; the water-soluble copper salt is copper nitrate or copper chloride; and the carbon source is glucose. Further preferably, the molar ratio of iron in the water-soluble iron salt to copper in the water-soluble copper salt is (0.5-2):1.

[0008] (2) removing water from the mixed solution to obtain a solid; the specific method is: placing the mixed solution in an oven at 50-90 °C and heating it until the water is evaporated;

[0009] (3) Grinding and mixing the solid matter and zinc carbonate to obtain a mixed powder; preferably, the zinc carbonate is basic zinc carbonate or zinc carbonate; the molar ratio of the added amount of zinc carbonate to the total amount of water-soluble iron salt and water-soluble copper salt is (5-10): (1-3).

[0010] (4) The mixed powder is calcined in a protective atmosphere. During the calcination process, the iron salt and the copper salt are respectively converted to form iron-copper nanoparticles, which serve as catalytic active sites; glucose is dehydrated and carbonized at high temperature to form amorphous carbon or a partially graphitized carbon skeleton; urea introduces nitrogen doping sites to adjust the electronic structure of the carbon material and enhance the catalytic activity, and finally obtains a FeCu@NC Fenton-type catalyst. Preferably, the protective atmosphere is an inert gas atmosphere such as argon. Further preferably, the calcination is a staged calcination, and the specific process is: the mixed powder is first calcined at a temperature of 450-650°C for the first time, and then calcined at a temperature of 930-1000°C for the second time to ensure that the metallic element zinc is completely volatilized. Specifically, the mixed powder is first calcined at 3-10 °C min under argon. -1 The temperature was raised to 450-650 °C at a heating rate of 10 °C / min under argon and maintained for 2 h. -1 The temperature was raised to 930-1000 °C at a heating rate of 1000 °C and maintained for 1 h. After calcination, the mixture was allowed to cool naturally to room temperature.

[0011] The reason for adding zinc carbonate in the above scheme is its unique chemical structure and properties. Zinc carbonate readily decomposes upon heating. This plays a crucial role in the subsequent calcination process. The decomposition product serves as a structure-directing agent and pore-regulating agent in the catalyst system. Specifically, the decomposition process is as follows: It first decomposes into carbon dioxide and zinc oxide at the temperature of the first calcination. Then, during the second calcination, the zinc oxide uses carbon as a reducing agent to produce elemental zinc metal. Finally, the zinc metal volatilizes at high temperatures and is removed from the system. During this process, zinc oxide helps build the catalyst's porous structure, increasing the catalyst's surface area, providing more active sites for the catalytic reaction and enhancing its activity. Furthermore, it can influence the dispersion of the metal particles (Fe and Cu) in the catalyst to a certain extent, ensuring a more uniform distribution of the metal particles within the carbon matrix and better exposing the metal nanoparticles to the catalyst surface, thereby enhancing the catalyst's stability and catalytic performance.

[0012] The present invention also provides a FeCu@NC Fenton-type catalyst, which is prepared by the preparation method described above.

[0013] The FeCu@NC Fenton-like catalyst provided by the present invention has promising application prospects in the catalytic degradation of organic pollutants. Its application comprises the following steps: adding the FeCu@NC Fenton-like catalyst to water containing organic pollutants to be treated, adding hydrogen peroxide as an oxidant, degrading the organic pollutants, and filtering to obtain treated water. This catalyst can be used in advanced oxidation techniques (heterogeneous Fenton-like oxidation reactions) to degrade organic pollutants. The filtered catalyst can be reused after simple treatment, such as drying, and exhibits excellent cyclic stability.

[0014] The present invention has the following beneficial effects:

[0015] The FeCu@NC Fenton-like catalyst provided by the present invention significantly improves the catalytic performance of the catalyst by simultaneously introducing Fe and Cu nanoparticles into the catalyst system and utilizing the synergistic promotion effect produced by Fe and Cu.

[0016] The preparation method provided by the present invention utilizes a staged calcination process to precisely control the reduction timing of ZnO. The specific mechanism is as follows: During the first calcination, the ZnO can be stably present due to the lower temperature; during the second calcination, due to the higher temperature, the strong reducing properties of carbon are utilized to reduce the ZnO to Zn. The second sintering temperature is controlled to be above the boiling point of Zn, allowing the Zn to volatilize, leaving behind a uniform pore structure. Using a conventional single-temperature calcination process would result in ZnO directly sublimating rather than fully reacting with carbon, resulting in insufficient porosity in the final product and poor catalyst performance.

[0017] The raw materials used in the present invention are cheap and readily available, the operation method is simple, and the synthesis is convenient. The prepared FeCu@NC catalyst can be applied to a heterogeneous Fenton-like oxidation reaction to efficiently degrade organic pollutants. Since the catalyst is simple to prepare and easy to industrialize, it has high efficiency in degrading pollutants and has extremely high application value in the treatment of organic pollutant wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 SEM and HR-TEM spectra of the FeCu@NC catalyst prepared in Example 1.

[0019] Figure 2 This is the Raman spectrum of the FeCu@NC catalyst prepared in Example 1.

[0020] Figure 3 This is the FT-IR spectrum of the FeCu@NC catalyst prepared in Example 1.

[0021] Figure 4This is a graph showing the time course of tetracycline degradation by catalysts prepared in different embodiments and comparative examples;

[0022] Figure 5 This is the SEM image of the catalyst prepared in Comparative Example 2. DETAILED DESCRIPTION

[0023] The present invention is further described below with reference to specific examples. However, the essence of the present invention is not limited to the following examples. The methods described are conventional methods unless otherwise specified, and the materials described are commercially available unless otherwise specified. Those skilled in the art will recognize that any simple modification or substitution based on the essence of the present invention falls within the scope of protection claimed by the present invention.

[0024] Example 1

[0025] A method for preparing a FeCu@NC-type Fenton catalyst comprises the following steps:

[0026] Step 1: 0.3 mmol Fe(NO3)2·9H2O, 0.3 mmol Cu(NO3)2·3H2O, 0.504 g C6H 12 Dissolve O6 and 2.2 g CO(NH2)2 in 20 mL of aqueous solution and evaporate to dryness at 80 °C. Add 1.586 g basic zinc carbonate and grind into powder.

[0027] Step 2: The ground powder was transferred to a corundum crucible and calcined in a tube furnace at 5 °C·min under argon. -1 The temperature was raised to 550 °C and held for 2 h, then heated at a rate of 5 °C·min -1 The temperature was raised to 1000 °C at a heating rate of 1000 °C and maintained for 1 h before naturally cooling to room temperature to obtain the target product, which was recorded as FeCu@NC.

[0028] Figure 1 The SEM and HR-TEM spectra of the FeCu@NC catalyst prepared in Example 1, wherein Figure a is the SEM image of FeCu@NC, Figure b is a local enlarged view of Figure a, and Figure c is the HR-TEM spectrum of FeCu@NC. Figure 1 It can be seen that iron and copper nanoparticles are loaded on N-doped carbon nanosheets with a wrinkled honeycomb structure.

[0029] Figure 2 This is the Raman spectrum of the FeCu@NC catalyst prepared in Example 1. -1 Two significant peaks were observed near the D ) and graphite structure (I G ) level. D / I G The value is close to 1, indicating that the catalyst synthesized by the method of this patent has good conductivity, which is conducive to improving the catalytic performance.

[0030] Figure 3 This is the FT-IR spectrum of the FeCu@NC catalyst prepared in Example 1. The basic skeleton structure of the FeCu@NC catalyst of the present invention can be confirmed from the FT-IR spectrum.

[0031] The FeCu@NC catalyst obtained in this example was used to degrade tetracycline in water: 3 mg of the FeCu@NC catalyst prepared in Example 1 was weighed and added to 50 mL of tetracycline at a concentration of 5 mg·L -1 100 μL of hydrogen peroxide was added to a water sample, shaken thoroughly at 25°C, and samples were taken and filtered at specific times to detect the residual tetracycline content in the aqueous solution. The concentration during the test was defined as the measured concentration, and the initial concentration was 5 mg·L -1 , then the removal rate = measured concentration / initial concentration.

[0032] Figure 4 Figure a shows the degradation results of tetracycline by the catalysts prepared in different embodiments and comparative examples in the presence of hydrogen peroxide. Figure 4 As shown in Figure (a), when the reaction time is 30 minutes, the catalyst prepared in Example 1 has a tetracycline removal rate of 63.2%. If only 100 μL of hydrogen peroxide is added without the catalyst of the present invention (marked as the blank group), the removal rate within 30 minutes is only 0.04%.

[0033] Comparative Example 1

[0034] Compared with Example 1, the difference in this comparative example is that 0.3 mmol Fe(NO3)2·9H2O and 0.3 mmol Cu(NO3)2·3H2O in step 1 are replaced with 0.6 mmol Fe(NO3)2·9H2O, and the other processes are the same as those in Example 1; the prepared catalyst is recorded as Fe@NC.

[0035] The catalyst obtained in this comparative example was used to degrade tetracycline in water: 3 mg of the catalyst prepared in the comparative example was weighed and added to 50 mL of tetracycline at a concentration of 5 mg·L -1 Add 100 μL of hydrogen peroxide to the water sample, shake it thoroughly in a shaker at 25°C, and take samples and filter them at specific times to detect the residual tetracycline content in the aqueous solution. Figure 4 As shown in Figure a, when the reaction time is 30 min, the removal rate of tetracycline by the catalyst prepared in Comparative Example 1 is 13.2%.

[0036] Comparative Example 2

[0037] Compared with Example 1, the difference in this comparative example is that 0.3 mmol Fe(NO3)2·9H2O and 0.3 mmol Cu(NO3)2·3H2O in step 1 are replaced with 0.6 mmol Cu(NO3)2·5H2O, and the other processes are the same as those in Example 1; the prepared catalyst is recorded as Cu@NC.

[0038] The catalyst obtained in this comparative example was used to degrade tetracycline in water: 3 mg of the catalyst prepared in the comparative example was weighed and added to 50 mL of tetracycline at a concentration of 5 mg·L -1 Add 100 μL of hydrogen peroxide to the water sample, shake it thoroughly in a shaker at 25°C, and take samples and filter them at specific times to detect the residual tetracycline content in the aqueous solution. Figure 4 As shown in Figure a, when the reaction time is 30 min, the removal rate of tetracycline by the catalyst prepared in Comparative Example 2 is 11.2%.

[0039] Comparative Example 3

[0040] Compared with Example 1, the difference in this comparative example is that basic zinc carbonate is not added in step 1, and the other processes are the same as those in Example 1.

[0041] Figure 5 This is a scanning electron microscope characterization image of the catalyst prepared in Comparative Example 3. It can be seen that most of the iron and copper nanoparticles are wrapped on the N-doped carbon sheet material and have no abundant pore structure.

[0042] The catalyst obtained in this comparative example was used to degrade tetracycline in water: 3 mg of the catalyst prepared in the comparative example was weighed and added to 50 mL of tetracycline at a concentration of 5 mg·L -1 100 μL of hydrogen peroxide was added to the water sample, shaken thoroughly in a shaker at 25°C, and samples were taken and filtered at specific times to detect the residual tetracycline content in the aqueous solution.

[0043] Figure 4 Figure b shows the degradation results of tetracycline by the catalyst prepared in Comparative Example 3 in the presence of hydrogen peroxide. It can be seen that when the reaction time is 30 min, the removal rate of tetracycline by the catalyst prepared in Comparative Example 3 is 8.6%.

[0044] Example 2:

[0045] Step 1: 0.2 mmol Fe(NO3)2·9H2O, 0.4 mmol Cu(NO3)2·3H2O, 0.504 g C6H 12Dissolve O6 and 2.2 g CO(NH2)2 in 20 mL of aqueous solution and evaporate to dryness at 80 °C. Add 1.586 g basic zinc carbonate and grind into powder.

[0046] Step 2: The same as step 2 of implementation 1; the obtained catalyst is recorded as FeCu2@NC.

[0047] The FeCu2@NC catalyst obtained in this example was used to degrade tetracycline in water: 3 mg of the FeCu2@NC catalyst prepared in Example 2 was weighed and added to 50 mL of tetracycline at a concentration of 5 mg·L -1 100 μL of hydrogen peroxide was added to the water sample, shaken thoroughly on a shaker, and samples were taken and filtered at specific times to detect the remaining tetracycline content in the aqueous solution.

[0048] Figure 4 Figure c shows the degradation results of tetracycline by the catalysts prepared in different examples in the presence of hydrogen peroxide. It can be seen that when the reaction time is 30 min, the removal rate of tetracycline by the catalyst prepared in Example 2 is 63.8%.

[0049] Example 3:

[0050] Step 1: 0.4 mmol Fe(NO3)2·9H2O, 0.2 mmol Cu(NO3)2·3H2O, 0.504 g C6H 12 Dissolve O6 and 2.2 g CO(NH2)2 in 20 mL of aqueous solution and evaporate to dryness at 80 °C. Add 1.586 g basic zinc carbonate and grind into powder.

[0051] Step 2: Same as step 2 of implementation 1; the obtained catalyst is denoted as Fe2Cu@NC.

[0052] The Fe2Cu@NC catalyst obtained in this example was used to degrade tetracycline in water: 1 mg of the Fe2Cu@NC catalyst prepared in Example 3 was weighed and added to 50 mL of tetracycline at a concentration of 5 mg·L -1 Add 100 μL of hydrogen peroxide to the water sample, shake it thoroughly in a shaker, and take samples and filter them at specific times to detect the remaining tetracycline content in the aqueous solution. Figure 4 As shown in Figure c, when the reaction time is 30 min, the removal rate of tetracycline by the catalyst prepared in Example 3 is 62.5%.

[0053] It should be noted that, in other embodiments, the purpose of the present invention can be achieved when the experimental process meets the following conditions:

[0054] The temperature for the first calcination is preferably 450-650°C, and may specifically be 450°C, 500°C, or 650°C, among others. The temperature for the second calcination is preferably 930-1000°C, and may specifically be 930°C, 950°C, or 1000°C, among others. Those skilled in the art may appropriately select the above process parameters based on actual needs.

[0055] Obviously, the described embodiments are only some embodiments of the present invention, not all 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.

Claims

1. A method for preparing a FeCu@NC Fenton-type catalyst, characterized in that: The following steps are involved: dissolving a water-soluble iron salt, a water-soluble copper salt, a carbon source and urea in water to obtain a mixed solution; removing water from the mixed solution to obtain a solid; Grinding and mixing the solid matter and zinc carbonate uniformly to obtain a mixed powder; The mixed powder was calcined in a protective atmosphere to obtain FeCu@NC Fenton-like catalyst; The carbon source is glucose; The calcination process is as follows: the mixed powder is first calcined at a temperature of 450-650°C for the first time, and then calcined at a temperature of 930-1000°C for the second time.

2. The method for preparing the FeCu@NC Fenton-type catalyst according to claim 1, wherein: The water-soluble iron salt is ferric nitrate or ferric chloride.

3. The preparation method of the FeCu@NC Fenton-type catalyst according to claim 1, characterized in that: The water-soluble copper salt is copper nitrate or copper chloride.

4. The method for preparing the FeCu@NC Fenton-type catalyst according to any one of claims 1 to 3, characterized in that: The molar ratio of iron in the water-soluble iron salt to copper in the water-soluble copper salt is (0.5-2):

1.

5. The method for preparing the FeCu@NC Fenton-type catalyst according to any one of claims 1 to 3, characterized in that: The zinc carbonate is basic zinc carbonate or zinc carbonate.

6. A FeCu@NC Fenton-type catalyst, characterized by: The invention relates to a novel crystalline silicon nitrate-containing slurry prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the FeCu@NC Fenton-type catalyst according to claim 6 in catalytic degradation of organic pollutants.

8. The use according to claim 7, characterized in that: The following steps are involved: The FeCu@NC Fenton-type catalyst as claimed in claim 6 is added to a water body to be treated containing organic pollutants, hydrogen peroxide is added as an oxidant, the organic pollutants are degraded, and then the treated water is obtained by filtration.

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