A composite C / N catalyst of a multi-metal alloy and a sulfide crystal, and a preparation method and application thereof

Abstract

The present invention discloses a multi-metal alloy and sulfide crystal composite C / N catalyst, its preparation method and application, belonging to the fields of catalysts and water treatment. First, a certain amount of iron nitrate, cobalt nitrate, nickel nitrate and sulfur-doped polyaminopyridine are respectively dissolved in four methanol / water solutions. After being dispersed under ultrasonic waves, the four solutions are mixed, and zinc chloride is added. After evaporation to dryness and programmed temperature calcination and carbonization under inert gas protection, the multi-metal alloy and sulfide crystal composite C / N catalyst is obtained. The catalyst prepared by the present invention can rapidly degrade phenanthrene in water by activating potassium peroxymonosulfate to generate hydroxyl radicals, sulfate radicals and singlet oxygen, has high catalytic efficiency, high utilization rate of oxidants, low cost, and good industrialization benefits.

Description

Technical Field

[0001] The present invention belongs to the technical fields of catalysts and water treatment, and relates to an advanced oxidation catalyst for repairing phenanthrene-polluted wastewater, specifically to a multi-metal alloy and sulfide crystal composite C / N catalyst and its preparation method and application. Background Art

[0002] As a refractory organic compound, due to its unique structure and stable configuration, phenanthrene has strong microbial toxicity and is difficult to degrade naturally. Physical methods are costly due to the need for external energy and are difficult to apply to the treatment of phenanthrene in water. Advanced oxidation methods are favored for their advantages such as simple operation, high degradation rate, high mineralization rate, and fast reaction rate. Currently used advanced oxidation catalysts are restricted by factors such as cost, catalytic efficiency, oxidant utilization rate, stability, and low active site loading. Therefore, it is crucial to develop a metal-supported catalyst with a high active site loading and controllable active sites. Summary of the Invention

[0003] One of the objectives of the present invention is to provide a preparation method for a multi-metal alloy and sulfide crystal composite C / N catalyst, which is convenient for synthesis.

[0004] Another objective of the present invention is to provide a multi-metal alloy and sulfide crystal composite C / N catalyst prepared by the above method, which can effectively activate potassium peroxymonosulfate to generate hydroxyl radicals, sulfate radicals, and singlet oxygen, and rapidly degrade phenanthrene in water.

[0005] The third objective of the present invention is to provide the application of the above multi-metal alloy and sulfide crystal composite C / N catalyst, which can efficiently degrade phenanthrene in water, has strong stability, and a very fast reaction rate.

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

[0007] On the first aspect, the present invention provides a preparation method for a C / N catalyst with Fe-N 7.6 active sites, comprising the following steps:

[0008] (1) Using a 50 vol% methanol aqueous solution as a solvent, prepare a ferric nitrate solution, a cobalt nitrate solution, and a nickel nitrate solution with concentrations of 25 - 25.5 mmol / L respectively;

[0009] (2) Mix the three solutions obtained in step (1), add sulfur-doped polyaminopyridine and zinc chloride, and evaporate to dryness under stirring conditions to obtain a black solid;

[0010] (3) Grind the black solid obtained in step (2) and subject it to programmed temperature calcination and carbonization under inert gas protection to obtain a black solid;

[0011] (4) The black solid obtained in step (3) is washed and dried to obtain a multi-metal alloy and sulfide crystal composite C / N catalyst.

[0012] Preferably, when the three solutions are mixed in step (2), the molar ratio of iron nitrate, cobalt nitrate and nickel nitrate is 1:1:1.

[0013] Preferably, the sulfur-doped polyaminopyridine in step (2) is polyaminopyridine doped with 3% ammonium persulfate, and the mass ratio of the sulfur-doped polyaminopyridine to zinc chloride is 1:1.

[0014] Preferably, the heating program for calcination and carbonization in step (3) is: heating from room temperature to 600 °C at a heating rate of 5 °C / min and holding for 2 h, then heating to 800 °C at a heating rate of 5 °C / min, and cooling with the furnace after holding for 2 h.

[0015] Preferably, in step (4), the washing step is to wash with dilute hydrochloric acid and deionized water respectively; the drying temperature is 105 °C and the drying time is 2 hours.

[0016] In a second aspect, the present invention also provides a multi-metal alloy and sulfide crystal composite C / N catalyst prepared by the above preparation method.

[0017] The catalyst includes a carbonized C / N catalyst skeleton and Zn 0.658 Fe 0.342 S, Zn 0.76 Co 0.24 S, NiS 33.3 Zn 32.3 and NiZn alloy and crystal active sites loaded on its surface and inside.

[0018] In a third aspect, the present invention also provides the application of the above multi-metal alloy and sulfide crystal composite C / N catalyst in the catalytic degradation of phenanthrene.

[0019] Specifically, the catalyst is added to the phenanthrene-containing wastewater to be treated, and then a potassium persulfate (PMS) solution is added, and the mixture is stirred and reacted at room temperature for 30 minutes. Among them, the concentration of phenanthrene in the system is 1 mg / L, the addition amount of the catalyst is 0.1 g / L, and the concentration of potassium persulfate in the system is 0.25 mmol / L.

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

[0021] 1. The catalyst of the present invention is simple to synthesize and has a very high utilization rate of the oxidant, and can realize industrial production;

[0022] 2. The catalyst of the present invention can generate sulfate radicals, hydroxyl radicals and singlet oxygen by activating potassium monopersulfate to rapidly degrade phenanthrene in water, with high catalytic efficiency, no secondary pollution, strong stability, and high economy and practicability. Description of the Drawings

[0023] Figure 1 Scanning electron microscope photograph of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention;

[0024] Figure 2 Scanning electron microscope and energy spectrum diagram of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention;

[0025] Figure 3 X-ray diffraction pattern of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention;

[0026] Figure 4 Electron paramagnetic resonance spectrum of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention for activating potassium monopersulfate to generate hydroxyl radicals, sulfate radicals and singlet oxygen;

[0027] Figure 5 Degradation curve of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention for activating potassium monopersulfate to degrade phenanthrene;

[0028] Figure 6 Repeatability test of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention. Detailed Description of the Invention

[0029] The present invention will be further described in detail below with reference to the drawings and specific examples.

[0030] Example 1

[0031] Weigh 1.535 g of Fe(NO3)2·9H2O, 1.105 g of Co(NO3)2·6H2O, and 1.105 g of Ni(NO3)2·6H2O respectively, dissolve them in three identical methanol / water (V / V = 1 / 1) solutions. After dispersing under ultrasonic waves for 5 minutes, let it stand for 30 minutes, and then make the volume up to 150 mL respectively. Mix the three solutions, add 5 g of polyaminopyridine doped with 3% ammonium persulfate and 5 g of ZnCl2, evaporate to dryness under magnetic stirring to obtain a black solid. After grinding, heat it from room temperature to 600 °C at a heating rate of 5 °C / min under nitrogen protection and keep it for 2 h, then heat it to 800 °C at a heating rate of 5 °C / min, keep it for 2 h and then cool it with the furnace to obtain a black solid. Wash it with 0.1 mol / L dilute hydrochloric acid and deionized water and dry it at 105 °C for 2 hours to obtain a multi-metal alloy and sulfide crystal composite C / N catalyst.

[0032] Figure 1 This is the scanning electron microscope photograph of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention; from Figure 1 it can be seen that the surface of the catalyst has a rich pore structure, and a large number of crystals and alloy particles are embedded.

[0033] Figure 2 This is the scanning electron microscope and energy spectrum diagram of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention; from Figure 2 it can be seen that the Fe, Co, Ni, and Zn metal elements are successfully loaded in the catalyst and exist in the form of crystals.

[0034] Figure 3 This is the X-ray diffraction pattern of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention; from Figure 3 it can be seen that the crystals embedded on the surface and inside of the catalyst are Zn 0.658 Fe 0.342 S, Zn 0.76 Co 0.24 S, NiS 33.3 Zn 32.3 and NiZn alloy and crystals.

[0035] Example 2

[0036] Add 1 mg of the catalyst prepared in Example 1 to 10 mL of phenanthrene-containing wastewater with a phenanthrene concentration of 1 mg / L, then add 0.77 mg of potassium hydrogen persulfate, and stir and react at room temperature for 30 minutes.

[0037] Figure 4 This is the degradation curve of the multi-metal alloy and sulfide crystal composite C / N catalyst activating potassium hydrogen persulfate to degrade phenanthrene measured in this example. From Figure 4It can be seen that in the presence of potassium monopersulfate alone, the degradation rate of phenanthrene was measured to be approximately 10%, while in the presence of both the multi-metal alloy and sulfide crystal composite C / N catalyst and potassium monopersulfate, the degradation rate of phenanthrene within 30 minutes was measured to be 83.65%. This composite catalyst can rapidly degrade phenanthrene in water by activating sodium persulfate with high catalytic efficiency.

[0038] Figure 5 This is the electron paramagnetic resonance spectrum of the multi-metal alloy and sulfide crystal composite C / N catalyst prepared in Example 1 of the present invention for activating potassium monopersulfate to generate hydroxyl radicals, sulfate radicals, and singlet oxygen. Figure 5 It can be seen that hydroxyl radicals, sulfate radicals, and singlet oxygen were generated during the activation of potassium monopersulfate by the multi-metal alloy and sulfide crystal composite C / N catalyst, which can act as oxidative species to synergistically oxidize and degrade phenanthrene.

[0039] Example 3

[0040] 0.2 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, then 0.77 mg of potassium monopersulfate was added, and the mixture was stirred at room temperature for 30 minutes. The degradation rate of phenanthrene was measured to be 38.1%.

[0041] Example 4

[0042] 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, 77 mg of potassium monopersulfate was added, and after stirring and reacting at room temperature for 2 h, a sample was taken to detect the degradation rate of phenanthrene and the catalyst was centrifuged. It was washed several times with deionized water and ethanol, vacuum dried at 105 °C, and then the above reaction was carried out again. This was repeated four times, and the degradation rates obtained for the four times were 83.6%, 75.60%, 65.75%, and 68.55% respectively. Figure 6 It shows that the catalyst has a high degradation rate during repeated use and good stability.

Claims

1. A preparation method of a composite C / N catalyst of a multi-metal alloy and a sulfide crystal, characterized in that, It includes the following steps: (1) Using an aqueous methanol solution with a volume fraction of 50% as the solvent, prepare ferric nitrate solution, cobalt nitrate solution, and nickel nitrate solution with concentrations of 25 - 25.5 mmol / L respectively; (2) Mix the three solutions obtained in step (1), add sulfur-doped polyaminopyridine and zinc chloride, and evaporate to dryness under stirring conditions to obtain a black solid; (3) Grind the black solid obtained in step (2) and perform programmed temperature calcination and carbonization under inert gas protection to obtain a black solid; the heating program for the calcination and carbonization is: heat from room temperature to 600 °C at a heating rate of 5 °C / min and hold for 2 h, then heat to 800 °C at a heating rate of 5 °C / min, hold for 2 h, and then cool with the furnace; (4) The black solid obtained in step (3) is washed and dried to obtain a multi-metal alloy and sulfide crystal composite C / N catalyst.

2. The preparation method of a multi-metal alloy and sulfide crystal composite C / N catalyst according to claim 1, wherein In step (2), when the three solutions are mixed, the molar ratio of ferric nitrate, cobalt nitrate, and nickel nitrate is 1:1:

1.

3. The preparation method of a multi-metal alloy and sulfide crystal composite C / N catalyst according to claim 1, characterized in that, In step (2), the sulfur-doped polyaminopyridine is polyaminopyridine doped with 3% ammonium persulfate, and the mass ratio of the sulfur-doped polyaminopyridine to zinc chloride is 1:

1.

4. The preparation method of a multi-metal alloy and sulfide crystal composite C / N catalyst according to claim 1, characterized in that, In step (4), the washing step is to wash with dilute hydrochloric acid and deionized water respectively; the drying temperature is 105 °C and the drying time is 2 hours.

5. A multi-metal alloy and sulfide crystal composite C / N catalyst prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the multi-metal alloy and sulfide crystal composite C / N catalyst according to claim 5 in the catalytic degradation of phenanthrene.

7. The application according to claim 6, wherein Add the catalyst to the phenanthrene-contaminated water, then add potassium peroxymonosulfate solution, and stir and react at room temperature for 30 minutes.

8. The application according to claim 7, characterized in that, The concentration of phenanthrene in the system is 1 mg / L, the addition amount of the catalyst is 0.1 g / L, and the concentration of potassium peroxymonosulfate in the system is 0.25 mmol / L.

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