A type with Fe-N 7.6 C / N catalysts with active sites, their preparation methods and applications

Abstract

The application discloses a C / N catalyst with Fe-N 7.6 active sites, a preparation method and application thereof, and belongs to the field of water treatment. Firstly, a chelate is formed by nitrogen anthracene and iron acetylacetone in a methanol environment, then the chelate is fully mixed with a polydiaminopyridine precursor, and is placed in a tubular furnace under nitrogen protection and is subjected to programmed temperature carbonization, and finally, the C / N catalyst with Fe-N 7.6 active sites is obtained. The catalyst prepared by the application can rapidly degrade phenanthrene in water through activation of potassium monopersulfate to generate singlet oxygen, has high catalytic efficiency, good stability, no secondary pollution, is convenient to operate, and has high economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology and relates to an advanced oxidation catalyst for remediating phenanthrene-contaminated water, specifically a catalyst with Fe-N 7.6 C / N catalysts with active sites, their preparation methods and applications. Background Technology

[0002] Phenylacetium, a type of polycyclic aromatic hydrocarbon (PAH), is characterized by its recalcitrant nature, teratogenicity, carcinogenicity, and mutagenicity, classifying it as a persistent organic pollutant with a wide range of threats. Its symmetrical structure and conjugation effects result in a relatively uniform electrostatic potential and stable chemical properties, making it difficult to remove. Advanced oxidation processes are typically used, employing reactive species such as free radicals to oxidize phenylacetium, achieving efficient degradation. However, currently used metal single-atom-doped advanced oxidation catalysts suffer from drawbacks such as low coordination numbers and easy detachment, hindering reuse. Therefore, developing a high-coordination-number metal single-atom-doped catalyst to activate potassium persulfate for the oxidative degradation of phenylacetium is crucial for the treatment of PAH-contaminated water bodies. Summary of the Invention

[0003] One of the objectives of this invention is to provide a Fe-N 7.6 The preparation method of C / N catalysts with active sites is simple.

[0004] A second objective of this invention is to provide a Fe-N product obtained by the above method. 7.6 The C / N catalyst with active sites can efficiently activate potassium persulfate to generate singlet oxygen to degrade phenanthrene in water.

[0005] The third objective of this invention is to provide the above-mentioned Fe-N 7.6 The application of C / N catalysts with active sites can efficiently degrade phenanthrene in water, with low cost, no secondary pollution, and strong stability.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a Fe-N 7.6 A method for preparing a C / N catalyst with active sites includes the following steps:

[0008] (1) Dissolve acetylacetone iron and anthracene in methanol, disperse by ultrasonication, and let stand for 20-30 minutes to obtain solution A;

[0009] (2) Add the polydiaminopyridine precursor and zinc chloride to solution A obtained in step (1), disperse by ultrasonication for 10-20 minutes, and stir at 50°C until the solution is completely evaporated to obtain solid B;

[0010] (3) Grind the solid B obtained in step (2) into powder, put it into a tube furnace under nitrogen protection for programmed temperature rise carbonization, and obtain solid C;

[0011] (4) Wash the solid C obtained in step (3) and dry it overnight to obtain Fe-N 7.6 C / N catalysts with active sites.

[0012] Preferably, the molar ratio of acetylacetone iron and nitrogen anthracene in step (1) is 1:2.

[0013] Preferably, in step (2), the mass ratio of iron acetylacetone to polydiaminopyridine precursor is 1:20, and the mass ratio of polydiaminopyridine precursor to zinc chloride is 1:1.

[0014] Preferably, the process of temperature-increasing carbonization in step (3) is as follows: first, the temperature is increased from room temperature to 600°C and held for 2 hours, then increased to 800°C and held for 2 hours, and finally cooled with the furnace. The total heating rate is 5°C / min.

[0015] Preferably, the washing step in step (4) is: washing three times each with dilute hydrochloric acid solution and deionized water.

[0016] Secondly, the present invention also provides a Fe-N compound prepared by the above preparation method. 7.6 C / N catalysts with active sites.

[0017] The C / N catalyst comprises a carbonized C / N catalyst framework and Fe-N supported on its surface and interior. 7.6 Active site.

[0018] Thirdly, the present invention also provides the above-mentioned Fe-N 7.6 Application of C / N catalysts with active sites in the catalytic degradation of phenanthrene.

[0019] Specifically, the catalyst is added to the phenanthrene-containing wastewater to be treated, followed by the addition of potassium persulfate (PMS) solution, and the mixture is stirred and reacted at room temperature for 2-3 hours. The concentration of phenanthrene in the system is 1 mg / L, the amount of catalyst added is 0.1 g / L, and the concentration of potassium persulfate in the system is 5 mmol / L.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The catalyst of this invention is simple to synthesize and has low cost, enabling industrial production;

[0022] 2. The catalyst of this invention can rapidly degrade phenanthrene in water by activating potassium persulfate to generate singlet oxygen. It has high catalytic efficiency, no secondary pollution, and its effect improves after repeated use, making it highly economical and practical. Attached Figure Description

[0023] Figure 1 The Fe-N prepared in Example 1 of this invention 7.6 Scanning electron microscope images of C / N catalysts with active sites;

[0024] Figure 2 The Fe-N prepared in Example 1 of this invention 7.6 Degradation curves of phenanthrene by potassium persulfate activated by C / N catalyst at active sites;

[0025] Figure 3 The Fe-N prepared in Example 1 of this invention 7.6 The C / N catalyst at the active site activates potassium persulfate to generate singlet oxygen. 1 Electron paramagnetic resonance spectrum of O2;

[0026] Figure 4 The Fe-N prepared in Example 1 of this invention 7.6 Stability test of C / N catalyst with active sites. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] 50 mg of ferric acetylacetone and 50.746 mg of anthracene were dissolved in 30 mL of methanol, ultrasonically dispersed for 5 min, allowed to stand for 30 min, and then diluted to 50 mL to obtain solution A. 1 g of polydiaminopyridine precursor and 1 g of ZnCl2 were added to solution A, ultrasonicated for 10 min, and then magnetically stirred at 50 °C until the solution was completely evaporated to dryness, yielding black solid B. This solid B was ground and placed in a tube furnace for calcination under nitrogen protection. The heating program was as follows: first, the temperature was increased from room temperature to 600 °C and held for 2 h, then increased to 800 °C and held for 2 h, and finally cooled with the furnace. The total heating rate was 5 °C / min. The resulting black solid C was ground and washed three times each with 0.1 mol / L dilute hydrochloric acid solution and deionized water, then dried overnight in a 105 °C oven to obtain Fe-N... 7.6 C / N catalyst with active sites (7.6 refers to the coordination number, meaning one Fe is coordinated with 7.6 N atoms around it).

[0030] Table 1 shows the Fe-N alloys prepared in Example 1 of this invention. 7.6EXAFS Co-k edge fitting parameters of C / N catalysts with active sites; Table 1 shows that Fe-N exists on the catalyst surface. 7.6 The presence of active sites indicates successful synthesis of the target product.

[0031] Table 1 EXAFS Co-k edge fitting parameters (S0) 2 =0.77)

[0032]

[0033] Table 2 shows the Fe-N prepared in Example 1 of this invention. 7.6 The elemental composition and content of the C / N catalyst at the active site; as shown in Table 2, Fe element was successfully loaded into the catalyst.

[0034] Table 2. Elements and Contents of Catalysts

[0035]

[0036] Figure 1 The Fe-N prepared in Example 1 of this invention 7.6 Scanning electron microscope (SEM) images of C / N catalysts with active sites; by Figure 1 It can be seen that there are abundant hierarchical porous structures on the surface of the catalyst and at the fracture.

[0037] Example 2

[0038] 1 mg of the catalyst prepared in Example 1 was added to 10 mL of phenanthrene-containing wastewater with a phenanthrene concentration of 1 mg / L, and then 15.4 mg of potassium persulfate was added. The mixture was stirred and reacted at room temperature for 2 h.

[0039] Figure 2 This is the Fe-N measured in this embodiment. 7.6 The degradation curve of phenanthrene by potassium persulfate activated by the active site of the C / N catalyst is shown in the figure. Figure 2 It can be seen that the degradation rate of phenanthrene does not exceed 20% only in the presence of potassium persulfate, while in the presence of Fe-N... 7.6 When C / N catalyst with active sites and potassium persulfate are present simultaneously, the degradation rate of phenanthrene is measured to be 81.65% within 2 hours. This composite catalyst can rapidly degrade phenanthrene in water by activating sodium persulfate, and has high catalytic efficiency.

[0040] Figure 3 The Fe-N prepared in Example 1 of this invention 7.6 The C / N catalyst at the active site activates potassium persulfate to generate singlet oxygen. 1 The electron paramagnetic resonance spectrum of O2) is obtained from Figure 3 It can be seen that it has Fe-N 7.6The C / N catalyst at the active site generates singlet oxygen during the activation of potassium persulfate, which can be used as an oxide species to oxidize and degrade phenanthrene.

[0041] Example 3

[0042] 2 mg of the catalyst prepared in Example 1 was added to 10 mL of phenanthrene-containing wastewater with a phenanthrene concentration of 1 mg / L, and then 15.4 mg of potassium peroxymonosulfate was added. The mixture was stirred at room temperature for 2 h, and the degradation rate of phenanthrene was measured to be 78.6%.

[0043] Example 4

[0044] 4 mg of the catalyst prepared in Example 1 was added to 10 mL of phenanthrene-containing wastewater with a phenanthrene concentration of 1 mg / L, and then 15.4 mg of potassium persulfate was added. The mixture was stirred at room temperature for 2 h, and the degradation rate of phenanthrene was measured to be 80.6%.

[0045] Example 5

[0046] 100 mg of the catalyst prepared in Example 1 was added to 1 L of phenanthrene-containing wastewater with a phenanthrene concentration of 1 mg / L. 1.54 g of potassium peroxymonosulfate was added, and the mixture was stirred at room temperature for 2 h. After stirring, the degradation rate of phenanthrene was measured and the catalyst was obtained by centrifugation. The catalyst was washed several times with deionized water and ethanol, dried under vacuum at 105 °C, and the above reaction was repeated. This process was repeated four times, and the degradation rates obtained for the four times were 81.65%, 92.55%, 85.8%, and 89.55%, respectively. Figure 4 This indicates that the catalyst exhibits a high degradation rate and good stability during repeated use.

Claims

1. A substance with Fe-N 7.6 A method for preparing a C / N catalyst with active sites includes the following steps: (1) Dissolve acetylacetone iron and nitrogen anthracene in methanol, disperse by ultrasonication, and let stand for 20-30 minutes to obtain solution A; the molar ratio of acetylacetone iron to nitrogen anthracene is 1:2; (2) Add the polydiaminopyridine precursor and zinc chloride to the solution A obtained in step (1), disperse ultrasonically for 10-20 minutes, and stir at 50°C until the solution is completely evaporated to obtain solid B; the mass ratio of acetylacetone iron to polydiaminopyridine precursor is 1:20, and the mass ratio of polydiaminopyridine precursor to zinc chloride is 1:

1. (3) Grind the solid B obtained in step (2) into powder and put it into a tube furnace under nitrogen protection for programmed temperature rise carbonization to obtain solid C; the programmed temperature rise carbonization steps are: first, raise the temperature from room temperature to 600℃, hold for 2 hours, then raise the temperature to 800℃, hold for 2 hours, and finally cool with the furnace. The whole process heating rate is 5℃ / min. (4) The solid C obtained in step (3) is washed and dried overnight to obtain Fe-N 7.6 C / N catalysts with active sites.

2. A Fe-N compound according to claim 1 7.6 A method for preparing a C / N catalyst with active sites, characterized in that, The washing steps described in step (4) are as follows: wash three times each with dilute hydrochloric acid solution and deionized water.

3. The Fe-N compound prepared by the method according to claim 1 or 2 7.6 C / N catalysts with active sites.

4. The Fe-N composition according to claim 3 7.6 Application of C / N catalysts with active sites in the catalytic degradation of phenanthrene.

5. The application according to claim 4, characterized in that, Add the catalyst to the phenanthrene-containing wastewater to be treated, then add potassium persulfate solution, and stir the reaction at room temperature for 2-3 hours.

6. The application according to claim 5, characterized in that, The concentration of phenanthrene in the system is 1 mg / L, the amount of catalyst added is 0.1 g / L, and the concentration of potassium persulfate in the system is 5 mmol / L.

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