A recyclable non-noble metal composite catalyst, a preparation method and application thereof

Abstract

The application discloses a recyclable non-noble metal composite catalyst and a preparation method and application thereof. The preparation method comprises the following steps: dissolving cucurbituril in an alcohol solvent, adding iron trichloride and sodium acetate, stirring, transferring into a reaction kettle for reaction, centrifuging, washing and drying to obtain a cucurbituril modified Fe3O4 material; adding the cucurbituril modified Fe3O4 material into an alcohol solvent, ultrasonicating, adding an alcohol solution of a nickel source and a copper source, stirring, then transferring into a reaction kettle for reaction, cooling to room temperature after the reaction is completed, centrifuging, washing and drying to obtain the non-noble metal composite catalyst. The composite catalyst prepared by taking magnetic Fe3O4 as a core and growing catalytically active metals Cu and Ni on the surface has excellent magnetism; the Fe3O4 surface contains supramolecular macrocyclic cucurbituril, the cucurbituril can be combined with Cu ions and Ni ions as a ligand, and the Fe3O4 is conducive to further efficient compounding of the catalytically active metals Cu and Ni, and the synthesis process is simple and easy to implement.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of organic dye treatment in industrial wastewater, and particularly relates to a recyclable non-noble metal composite catalyst and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of modern industry, agriculture and urbanization, water pollution caused by organic matter has become one of the problems to be solved. Azo dyes and nitroaromatic compounds, which are highly toxic and carcinogenic to humans, are widely exposed to aquatic ecosystems and are the most typical organic pollutants. At present, various technologies such as catalysis, adsorption and biodegradation have been used to remove these organic pollutants. Among them, the catalytic reduction of azo dyes and nitroaromatics to medicinal intermediates or relatively low-toxicity products is a promising method in line with the concept of sustainable development. In order to improve the efficiency of catalytic reduction of organic pollutants, different types of high-performance catalysts have been developed in recent years, such as noble metal catalysts (gold, palladium, ruthenium, rhodium nanoparticles), metal oxides (Co3O4, CuO-ZnO). However, the catalysts reported so far are often expensive and difficult to recycle, which is not suitable for industrial wastewater treatment. Therefore, it is of great significance to develop efficient, inexpensive and recyclable catalysts for the degradation of organic pollutants in wastewater. SUMMARY

[0003] In order to solve the problems of high cost and difficult recycling of noble metal catalysts, the present application provides a magnetic Fe3O4 composite copper and nickel non-noble metal material and a preparation method and application thereof in catalytic degradation of organic pollutants.

[0004] In order to achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0005] The present application provides a preparation method of a recyclable non-noble metal composite catalyst, comprising the following steps:

[0006] (1) Dissolve cucurbituril in an alcohol solvent, add ferric chloride and sodium acetate, stir and then transfer to a reaction kettle for reaction, and then centrifuge, wash and dry to obtain a cucurbituril-modified Fe3O4 material;

[0007] (2) Add the cucurbituril-modified Fe3O4 material to an alcohol solvent, ultrasonic, add an alcohol solution of a nickel source and a copper source, stir, and then transfer to a reaction kettle for reaction. After the reaction is completed, cool to room temperature, centrifuge, wash and dry to obtain the non-noble metal composite catalyst.

[0008] Preferably, the cucurbituril is at least one of cucurbit[6]uril, cucurbit[7]uril and cucurbit[8]uril.

[0009] Preferably, the molar ratio of the cucurbituril to ferric chloride is 1:18-22.

[0010] Preferably, in step (1), the temperature of the reaction is 190-210℃, and the reaction time is 6-10h.

[0011] Preferably, the drying temperature is 40-80℃, and the drying time is 3-6h.

[0012] Preferably, the nickel source is at least one of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate.

[0013] Preferably, the copper source is at least one of copper sulfate, copper chloride, copper nitrate, and copper acetate.

[0014] Preferably, the alcohol solvent comprises at least one of ethylene glycol and glycerol.

[0015] Preferably, in step (2), the concentration of the cucurbituril-modified Fe3O4 material in the reaction mixture in the reaction kettle is 0.5-2mg / mL, the concentration of the nickel source metal atoms is 1-4mM, and the concentration of the copper source metal atoms is 1-4mM.

[0016] Preferably, in step (2), the temperature of the reaction is 100-200℃, and the reaction time is 6-24h.

[0017] The second aspect of the present application provides the catalyst prepared by the preparation method of the recyclable non-noble metal composite catalyst.

[0018] The recyclable non-noble metal composite catalyst prepared by the present application is a spherical nanoparticle with rough surface, wherein the Cu on the surface is hydrothermally reduced to 0 valence, and the Ni is in +2 valence; the average particle size of the catalyst is 230-270nm.

[0019] The third aspect of the present application provides the application of the catalyst in catalyzing sodium borohydride to degrade congo red in wastewater.

[0020] The principle of the present application is that BH4 -1 After the ion diffusion to the surface of Fe3O4@Ni-Cu, the electron is transferred to Fe3O4@Ni-Cu and hydrogen is released. The Fe3O4@Ni-Cu with electron can activate the azo bond of congo red molecule, that is, the congo red molecule is combined with Fe3O4@Ni-Cu through the oxygen and sulfur atoms in the molecular structure, the conjugation effect of the azo bond with them is weakened, so that the azo bond is more easily broken. In the process of reducing and catalyzing congo red, the Fe3O4@Ni-Cu catalyst as an electron storage tank provides electrons, and the BH4 -1The ion emission hydrogen gas together reduces the -N=N- of the Congo red to -NH-NH-, and further reduction makes the nitrogen-nitrogen single bond break. The reaction product is released from the catalyst surface to the solution, and the solution also changes from orange to colorless.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] (1) The composite catalyst prepared by taking magnetic Fe3O4 as the core and growing catalytically active metals Cu and Ni on the surface of the core has excellent magnetism. Through the action of an external magnetic field, the Fe3O4@Ni-Cu catalyst can be rapidly separated from the aqueous dispersion system within 15 s, and the recycling of the nanometer catalyst can be easily realized.

[0023] (2) The surface of Fe3O4 contains supramolecular macrocyclic cucurbituril, and the cucurbituril can bind Cu ions and Ni ions as ligands, which is conducive to the further efficient compounding of catalytically active metals Cu and Ni on the surface of Fe3O4, and the synthesis process is simple and easy to implement.

[0024] (3) The Fe3O4@Ni-Cu bimetallic nanometer catalyst has more excellent catalytic capacity than the single Fe3O4@Ni and Fe3O4@Cu. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The SEM electron micrograph, particle size distribution graph and EDS element distribution graph of the Fe3O4@Ni-Cu bimetallic nanometer catalyst;

[0026] Figure 2 The performance graph of the nanometer catalyst in the example in the degradation of Congo red by sodium borohydride. DETAILED DESCRIPTION

[0027] The specific embodiments of the present application will be further described below. It should be noted that the description of these embodiments is used to help understand the present application, but does not constitute a limitation on the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0028] The experimental methods in the following examples are all conventional methods unless otherwise specified, and the test materials used in the following examples are all commercially available unless otherwise specified.

[0029] Example 1

[0030] The present embodiment provides a preparation method of cucurbituril-stabilized Fe3O4 nanometer material, which specifically comprises the following steps:

[0031] Into a 250 mL three-necked flask, 0.4 mmol cucurbit [7] uril and 40 mL ethylene glycol solvent were added and ultrasonicated for 5 min to make the cucurbituril completely dissolved. Then 1.300 g anhydrous ferric chloride was added and ultrasonicated for another 5 min. After the ultrasonic treatment, the mixture was placed on a magnetic stirrer and 2.400 g sodium acetate was added. After stirring for 30 min, the mixture was transferred into a high-pressure autoclave and placed in an oven at 200 ℃ for 10 h. After the reaction, the reaction system was cooled to room temperature and centrifuged at 10000 rpm and 4 ℃ for 5 min. The reaction solvent was removed and washed with deionized water for three times. The centrifuge tube containing the product was placed in an oven to dry, and the cucurbituril-stabilized Fe3O4 nanomaterial was obtained.

[0032] Example 2

[0033] The present example provides a preparation method of Fe3O4@Ni nanocatalyst, which specifically comprises the following steps:

[0034] 0.030 g of the cucurbituril-stabilized Fe3O4 nanomaterial prepared in Example 1 was weighed as a raw material, and 30 mL of ethylene glycol was weighed as a solvent, which were added into a 250 mL three-necked flask in sequence. The reaction flask was then placed in an ultrasonic cleaner and ultrasonicated for 5 min. Nickel dichloride hexahydrate (0.020 g) was added into the ethylene glycol solution of Fe3O4 and mechanically stirred for 30 min. Then the mixture was transferred into a high-pressure autoclave and placed in an oven at 200 ℃ for 10 h. After the reaction, the reaction system was cooled to room temperature and the solution was transferred into a centrifuge tube and centrifuged at 10000 rpm. The reaction solvent was removed and washed with deionized water for three times. Finally, the mixture was placed in an oven to dry, and the Fe3O4@Ni nanocatalyst was obtained.

[0035] Example 3

[0036] The present example provides a preparation method of Fe3O4@Cu nanocatalyst, which specifically comprises the following steps:

[0037] 0.030 g of the cucurbituril-stabilized Fe3O4 nanomaterial prepared in Example 1 was weighed as a raw material, and 30 mL of ethylene glycol was weighed as a solvent, which were added into a 250 mL three-necked flask in sequence. The reaction flask was then placed in an ultrasonic cleaner and ultrasonicated for 5 min. Nickel dichloride hexahydrate (0.020 g) was added into the ethylene glycol solution of Fe3O4 and mechanically stirred for 30 min. Then the mixture was transferred into a high-pressure autoclave and placed in an oven at 200 ℃ for 10 h. After the reaction, the reaction system was cooled to room temperature and the solution was transferred into a centrifuge tube and centrifuged at 10000 rpm. The reaction solvent was removed and washed with deionized water for three times. Finally, the mixture was placed in an oven to dry, and the Fe3O4@Ni nanocatalyst was obtained.

[0038] Example 4

[0039] The embodiment provides a preparation method of Fe3O4@Ni-Cu bimetallic nanocatalyst, and specifically comprises the following steps:

[0040] 0.030g of the cucurbituril-stabilized Fe3O4 nanomaterial prepared in the preparation of Example 1 is taken as a raw material, and 30mL of ethylene glycol is taken as a solvent, which are sequentially added into a 250mL three-necked flask, and then the reaction flask is placed into an ultrasonic cleaner for ultrasonic treatment for 5min. Nickel dichloride hexahydrate (0.020g) and anhydrous copper dichloride (0.010g) are added into the ethylene glycol solution of Fe3O4 respectively, and mechanical stirring is performed for 30min, and then the reaction flask is transferred into a high-pressure reaction kettle, and placed into an oven for reaction at 200℃ for 10h. After the reaction is completed, the reaction system is cooled to room temperature, the solution is transferred into a centrifuge tube, centrifugation is performed at 10000rpm, the reaction solvent is removed and washed with deionized water for three times, and finally placed into an oven for drying, to obtain the Fe3O4@Ni-Cu bimetallic nanocatalyst.

[0041] Example 5

[0042] Experiment of catalyst catalytic degradation performance of congo red:

[0043] 100mL of 0.1mmol congo red solution is prepared, and the original absorbance of the solution is measured; 10mL of 0.1M sodium borohydride solution is prepared.

[0044] 20mL of the congo red solution is poured into a 100mL beaker, 0.45mL of the sodium borohydride solution is added, and the absorbance of the congo red solution is measured every 1min under the condition that only the sodium borohydride exists.

[0045] 20mL of the congo red solution is poured into a 100mL beaker, 5mg of the catalyst is added, ultrasonic treatment is performed for 5min, and then 0.45mL of the sodium borohydride solution is added. The absorbance of the congo red solution is measured every 1min under the condition that the catalyst and the sodium borohydride exist. After the experiment, the used catalyst is separated from the reaction solution by using the magnetic force of an external magnetic field, and washed with purified water for three times, and dried for standby, and the recycling performance is measured.

[0046] Figure 1 It is the SEM electron micrograph (A), the particle size distribution graph (B) and the EDS element distribution graph (C) of the Fe3O4@Ni-Cu bimetallic nanocatalyst described in Example 4. As can be seen from the figure, the Fe3O4@Ni-Cu is uniform spherical, the average particle size is 250nm, and the Ni and Cu elements are successfully doped inside.

[0047] Figure 2The performance graphs of the nanometer catalysts in examples 1, 2, 3 and 4 in catalyzing degradation of Congo red by sodium borohydride are shown in the figures, wherein figure A is the performance graph of only adding sodium borohydride, figure B is the performance graph of adding sodium borohydride and Fe3O4@Ni, figure C is the performance graph of adding sodium borohydride and Fe3O4@Cu, and figure D is the performance graph of adding sodium borohydride and Fe3O4@Ni-Cu. It can be seen from the figures that the Fe3O4@Ni-Cu bimetallic nanometer catalyst has the optimal catalytic performance, and Congo red can be completely catalytically degraded in 12 minutes.

[0048] The embodiments of the present application are described in detail above, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. A method for producing a recyclable non-noble metal composite catalyst, characterized by, The method comprises the following steps: (1) dissolving cucurbituril in an alcohol solvent, adding ferric chloride and sodium acetate, stirring, transferring to a reaction kettle for reaction, then centrifuging, washing and drying to obtain a cucurbituril-modified Fe3O4 material; (2) adding the cucurbituril-modified Fe3O4 material into an alcohol solvent, ultrasonicating, adding an alcohol solution of a nickel source and a copper source, stirring, then transferring to a reaction kettle for reaction, cooling to room temperature after the reaction, centrifuging, washing and drying to obtain the non-noble metal composite catalyst.

2. The method for producing a recyclable non-noble metal composite catalyst according to claim 1, characterized by, The cucurbituril is at least one of cucurbit[6]uril, cucurbit[7]uril and cucurbit[8]uril.

3. The method for preparing the recyclable non-precious metal composite catalyst according to claim 2, characterized in that, The molar ratio of the cucurbituril to ferric chloride is 1:18-22.

4. The method for preparing the recyclable non-precious metal composite catalyst according to claim 1, characterized in that, In step (1), the reaction temperature is 190-210℃, and the reaction time is 6-10h.

5. The method for preparing the recyclable non-precious metal composite catalyst according to claim 1, characterized in that, The nickel source is at least one of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate.

6. The method for preparing the recyclable non-precious metal composite catalyst according to claim 1, characterized in that, The copper source is at least one of copper sulfate, copper chloride, copper nitrate and copper acetate.

7. The method for preparing the recyclable non-precious metal composite catalyst according to claim 1, characterized in that, In step (2), the concentration of the cucurbituril-modified Fe3O4 material in the reaction mixture in the reaction kettle is 0.5-2mg / mL, the metal atom concentration of the nickel source is 1-4mM, and the metal atom concentration of the copper source is 1-4mM.

8. The method for preparing the recyclable non-precious metal composite catalyst according to claim 1, characterized in that, In step (2), the reaction temperature is 100-200℃, and the reaction time is 6-24h.

9. A catalyst prepared by the method for preparing the recyclable non-noble metal composite catalyst according to any one of claims 1-8.

10. Application of the catalyst according to claim 9 to catalyzing degradation of congo red in waste water by sodium borohydride.

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