A hydroxyl copper fluoride / cuprous oxide composite catalyst and a preparation method thereof

Abstract

The application discloses a preparation method of a hydroxyl copper fluoride / cuprous oxide composite catalyst, which comprises the following steps: dispersing hydroxyl copper fluoride as a copper source in deionized water, and using glucose, hydrazine hydrate or sodium borohydride as a reducing agent to reduce a small amount of cuprous oxide on the surface of the hydroxyl copper fluoride in situ to obtain a target product. The preparation process is simple, and the operability is good. Through the synergistic effect of photocatalysis and a Fenton-like system, the hydroxyl copper fluoride / cuprous oxide composite catalyst has good catalytic performance and cycle stability under visible light irradiation, and can be used for degrading organic pollutants such as antibiotics.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalyst preparation, and particularly relates to a hydroxyl copper fluoride / cuprous oxide (Cu2(OH)3F / Cu2O) composite catalyst and a preparation method thereof. BACKGROUND

[0002] With the development of modern analysis technology and the enhancement of people's environmental safety awareness, emerging organic pollutants such as antibiotics have attracted widespread attention in natural water environment. The extensive use of antibiotics can easily lead to their entry into the environment through direct or indirect pathways, and further cause environmental pollution and harm to biological health. Therefore, how to effectively remove these high-concentration and refractory organic wastewater has become a key research field.

[0003] Photocatalysis is a kind of advanced oxidation process for degrading organic wastewater with low energy consumption, high efficiency and no secondary pollution, but the photo-generated electrons and holes generated in the photocatalysis process are easy to recombine, which hinders the degradation of pollutants on the surface of the catalyst. The Fenton-like process is also a kind of advanced oxidation process with the advantages of simple operation process and wide application range, but it also has the disadvantages of difficult recycling of catalyst, incomplete degradation of organic pollutants, and narrow pH operation range. Therefore, the photocatalysis and Fenton-like process can be combined to produce a synergistic effect through the interaction of catalyst, hydrogen peroxide and light, overcome the respective shortcomings, and improve the degradation efficiency of organic wastewater.

[0004] In recent years, due to the multiple oxidation states (Cu 0 Cu Ⅰ Cu Ⅱ Cu Ⅲ ) of copper-based materials, they have unique characteristics and properties. Using copper-based materials as Fenton-like reagents can overcome the defects of traditional Fenton reagents in reagent application, such as narrow pH operation range, difficult recycling of catalyst, and secondary pollution. The combination of Cu + and Cu 2+ improves the mutual transformation between the two valence states of copper in the reaction and improves the cyclic stability of the catalyst.

[0005] Chinese patent document No. CN2020109097065 discloses a hydroxyl copper fluoride / carbon nitride composite catalyst and a preparation method and application thereof. In the invention, the preparation of the composite catalyst is by mechanical grinding method, and the target product is obtained by mechanical grinding of hydroxyl copper fluoride and carbon nitride. However, the present application is by in-situ reduction method, and the target composite catalyst is obtained by in-situ reduction of cuprous oxide on the surface of hydroxyl copper fluoride as the main body.

[0006] The Chinese patent document No. CN 115970711A discloses a preparation method of cuprous oxide / cupric sulfide nanocomposite on April 18, 2023. In the invention, the preparation of the composite catalyst is carried out by using copper acetate monohydrate as the copper source, mixing with elemental sulfur powder and sodium acetate in the medium of ethylene glycol, and then obtaining the target product through solvothermal reaction. However, in the present invention, copper hydroxy fluoride is used as the copper source, and the copper hydroxy fluoride is dispersed in deionized water and a reducing agent is added to generate copper hydroxy fluoride / cuprous oxide composite catalyst in situ. SUMMARY

[0007] The present invention aims to overcome the defects of the prior art and provides a copper hydroxy fluoride / cuprous oxide (Cu2(OH)3F / Cu2O) composite catalyst, which is prepared by reducing cuprous oxide in situ from copper hydroxy fluoride in a simple and convenient manner. Through the synergistic effect of two advanced oxidation technologies, the valence state cycle of Cu + and Cu 2+ is realized, the transfer of electric charge also improves the separation efficiency of photo-generated carriers, and the rate of Fenton-like reaction is accelerated, thereby having excellent effect of degrading organic pollutants.

[0008] The present invention also provides a preparation method of the above-mentioned copper hydroxy fluoride / cuprous oxide (Cu2(OH)3F / Cu2O) composite catalyst material and its application in degrading organic pollutants, such as tetracycline hydrochloride, in a photo-Fenton system.

[0009] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0010] A copper hydroxy fluoride / cuprous oxide composite catalyst, which is composed of copper hydroxy fluoride and cuprous oxide generated in situ by reduction of copper hydroxy fluoride.

[0011] The present invention provides a preparation method of the above-mentioned copper hydroxy fluoride / cuprous oxide composite catalyst, which includes the following steps:

[0012] Copper hydroxy fluoride is dispersed in deionized water, a reducing agent is added at a temperature of 5-80°C for 0.5-8 hours, a small amount of cuprous oxide is generated in situ on the surface of copper hydroxy fluoride (the copper source for generating cuprous oxide is copper hydroxy fluoride), and the product is filtered, washed, and dried to obtain the composite catalyst.

[0013] Specifically, the reducing agent can be one or more of glucose, hydrazine hydrate, sodium borohydride, etc. The reducing agent can be added directly or in the form of an aqueous solution.

[0014] Further, when the reducing agent is hydrazine hydrate, the mass-volume ratio of the hydroxyl copper fluoride and the hydrazine hydrate is 1g:2.5-400μL; when the reducing agent is glucose, the mass ratio of the hydroxyl copper fluoride and the glucose is 1g:2-13g; when the reducing agent is sodium borohydride, the mass ratio of the hydroxyl copper fluoride and the sodium borohydride is 1g:0.001-0.05g.

[0015] Further, the mass ratio of the hydroxyl copper fluoride and the deionized water can be 1g:20-400g.

[0016] Further preferably, the stirring speed during the reaction can be 350-600rpm.

[0017] Specifically, the washing can be washing with deionized water for 2-3 times and washing with anhydrous ethanol for 1-2 times; and the drying can be vacuum drying at 60±10℃ for 3-5 hours.

[0018] The application further provides application of the above-mentioned hydroxyl copper fluoride / cuprous oxide composite catalyst in degradation of organic pollutants in a photo-Fenton-like process. Further, the organic pollutants are tetracycline hydrochloride, rhodamine B, ciprofloxacin or bisphenol A, etc.

[0019] The hydroxyl copper fluoride / cuprous oxide (Cu2(OH)3F / Cu2O) composite catalyst of the application is composed of hydroxyl copper fluoride and cuprous oxide generated by in-situ reduction of the hydroxyl copper fluoride. The hydroxyl copper fluoride can be prepared according to the existing patent literature (CN2020109097065), and the preparation process can be specifically as follows: copper nitrate and hexamethylenetetramine are dissolved in deionized water, and the pH is adjusted to neutral with ammonia water, then fluoride is added and stirred uniformly, and the mixture is hydrothermally treated at 85-135℃ in a reaction kettle under sealed conditions for 2-8h, and then naturally cooled to room temperature, washed, and dried to obtain a light blue powder sample, which is the hydroxyl copper fluoride; the fluoride is one or a mixture of two or more of sodium fluoride, potassium fluoride and calcium fluoride. The mass ratio of copper nitrate, hexamethylenetetramine and fluoride is 1.4-1.5:0.8-0.9:1.2-1.3.

[0020] The application synthesizes the Fenton-like reagent hydroxyl copper fluoride by a hydrothermal method, and obtains a hydroxyl copper fluoride / cuprous oxide composite catalyst by in-situ reduction. In the prepared hydroxyl copper fluoride / cuprous oxide composite catalyst, the cuprous oxide is dispersed on the surface of the hydroxyl copper fluoride; the cuprous oxide reduced by the reducing agent has a nano-polyhedral structure with very small size, and the hydroxyl copper fluoride has a loose conical structure; the composite catalyst material has good photo-Fenton-like degradation performance and can be used for degradation of various organic pollutants.

[0021] Compared with the prior art, the application has the following advantages:

[0022] The application takes hydroxyl copper fluoride as the main body, and obtains the hydroxyl copper fluoride / cuprous oxide composite catalyst by simple in-situ reduction, and has the advantages of simple operation process, short preparation time and low cost.

[0023] The hydroxyl copper fluoride / cuprous oxide composite catalyst is used for removal and degradation of organic pollutants under visible light irradiation, and the defects of each other are made up, and the synergistic effect of the composite catalyst expands the application range of single material. Test results show that the hydroxyl copper fluoride / cuprous oxide composite catalyst has extremely excellent light Fenton-like degradation performance under simulated sunlight, can achieve rapid degradation of pollutants, and has great potential in treating industrial wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 SEM image of the hydroxyl copper fluoride / cuprous oxide prepared in Example 2 of the application;

[0025] Figure 2 XRD image of the hydroxyl copper fluoride / cuprous oxide prepared in Example 2 of the application;

[0026] Figure 3 Performance graph of the hydroxyl copper fluoride / cuprous oxide prepared in Examples 3, 4 and 5 of the application in degrading tetracycline hydrochloride;

[0027] Figure 4 Cycle experiment result graph of the hydroxyl copper fluoride / cuprous oxide prepared in Example 1 of the application. DETAILED DESCRIPTION

[0028] The technical solutions of the application are further described in detail in combination with the examples, but the protection scope of the application is not limited thereto.

[0029] In the following examples, if not otherwise specified, the raw materials used are ordinary commercially available products or can be obtained by preparing according to the conventional techniques in the art.

[0030] In the examples, the hydroxyl copper fluoride used is prepared by the following steps:

[0031] 1) 1.44 g of copper nitrate, 0.82 g of hexamethylenetetramine were dissolved in a polytetrafluoroethylene liner containing 60 ml of deionized water, stirred for 10 min, then adjusted to neutral pH with ammonia water, and then added 1.28 g of sodium fluoride, and continued to stir for 10 min;

[0032] 2) Put the product of step 1) into a reaction kettle and seal, then transfer into a blast drying oven for hydrothermal treatment at 95℃ for 2h, naturally cool to room temperature, wash with deionized water for 3 times, dry at 60℃ for 4h to obtain a light blue powder sample, which is hydroxyl copper fluoride Cu2(OH)3F.

[0033] Example 1, preparation of 1µL hydrazine hydrate reduced hydroxyl copper fluoride / copper(I) oxide composite catalyst

[0034] A method for preparing a hydroxyl copper fluoride / copper(I) oxide composite catalyst, comprising the following steps:

[0035] 1) Disperse 0.2g of hydroxyl copper fluoride powder in 50g of deionized water, add 1µL of hydrazine hydrate at 20℃, and stir for 2h (stirring speed is 450rpm);

[0036] 2) After filtering the mixture obtained in step 1), wash with deionized water for 3 times, then wash with anhydrous ethanol for 2 times, and then put the product into a vacuum drying oven at 60℃ for drying for 4h to obtain the hydroxyl copper fluoride / copper(I) oxide composite catalyst.

[0037] Example 2, preparation of 10µL hydrazine hydrate reduced hydroxyl copper fluoride / copper(I) oxide composite catalyst

[0038] A method for preparing a hydroxyl copper fluoride / copper(I) oxide composite catalyst, comprising the following steps:

[0039] 1) Disperse 0.2g of hydroxyl copper fluoride powder in 50g of deionized water, add 10µL of hydrazine hydrate at 20℃, and stir for 2h (stirring speed is 450rpm);

[0040] 2) Refer to step of example 1.

[0041] Figure 1 The SEM image of the hydroxyl copper fluoride / copper(I) oxide composite catalyst generated in example 2 is given, which can be seen that the in-situ reduced copper(I) oxide is dispersed on the surface of the hydroxyl copper fluoride, and the copper(I) oxide structure is a nano-polyhedron with very small size, and the hydroxyl copper fluoride is a loose cone structure.

[0042] Figure 2 The XRD image of the hydroxyl copper fluoride / copper(I) oxide composite catalyst generated in example 2 is given, and by comparing the standard cards of hydroxyl copper fluoride and copper(I) oxide, it can be accurately seen from Figure 1 that the composite catalyst contains the peaks corresponding to hydroxyl copper fluoride and copper(I) oxide, indicating that the copper(I) oxide is successfully generated in-situ on the surface of the hydroxyl copper fluoride.

[0043] Example 3, preparation of 5µL hydrazine hydrate reduced hydroxyl copper fluoride / copper(I) oxide composite catalyst

[0044] A preparation method of a hydroxyl copper fluoride / cuprous oxide composite catalyst, comprising the following steps:

[0045] 1) 0.2 g of hydroxyl copper fluoride powder was dispersed in 50 g of deionized water, 5 μL of hydrazine hydrate was added at 20°C, and the reaction was stirred for 2 h (stirring speed was 450 rpm);

[0046] 2) The step refers to Example 1.

[0047] Example 4,

[0048] A preparation method of a hydroxyl copper fluoride / cuprous oxide composite catalyst, referring to Example 2, the difference is that the reducing agent hydrazine hydrate is replaced with glucose. It specifically comprises the following steps:

[0049] 1) 2.97 g of glucose was dissolved in 15 g of deionized water to prepare a 1 mol / L glucose solution;

[0050] 2) 0.5 g of hydroxyl copper fluoride powder was dispersed in 25 g of deionized water, and the glucose solution prepared in step 1) was added at 40°C, and the reaction was stirred for 2 h (stirring speed was 450 rpm);

[0051] 3) The step refers to step 2) in Example 1.

[0052] Example 5,

[0053] A preparation method of a hydroxyl copper fluoride / cuprous oxide composite catalyst, referring to Example 2, the difference is that the reducing agent hydrazine hydrate is replaced with sodium borohydride. It specifically comprises the following steps:

[0054] 1) 0.00472 g of sodium borohydride was dissolved in 25 g of deionized water to prepare a 0.005 mol / L sodium borohydride solution;

[0055] 2) 0.5 g of hydroxyl copper fluoride powder was dispersed in 25 g of deionized water, and the sodium borohydride solution prepared in step 1) was added at 40°C, and the reaction was stirred for 2 h (stirring speed was 450 rpm);

[0056] 3) The step refers to step 2) in Example 1.

[0057] Example 6,

[0058] A preparation method of a hydroxyl copper fluoride / cuprous oxide composite catalyst, referring to Example 3, the difference is that the amount of deionized water is 20 g. It specifically comprises the following steps:

[0059] 1) 0.2 g of copper hydroxyl fluoride powder was dispersed in 20 g of deionized water, 5 μL of hydrazine hydrate was added at 20 °C, and the reaction was stirred for 2 h (stirring speed was 450 rpm);

[0060] 2) The step refers to Example 1.

[0061] Example 7,

[0062] A method for preparing a copper hydroxyl fluoride / copper(I) oxide composite catalyst, referring to Example 4, the difference is that the reaction temperature is 60 °C. It specifically includes the following steps:

[0063] 1) The step refers to Example 4;

[0064] 2) 0.5 g of copper hydroxyl fluoride powder was dispersed in 25 g of deionized water, and the glucose solution prepared in step 1) was added at 60 °C, and the reaction was stirred for 2 h (stirring speed was 450 rpm);

[0065] 3) The step refers to Example 4.

[0066] Catalyst degradation test:

[0067] 10 mg of copper hydroxyl fluoride / copper(I) oxide composite catalyst prepared in Examples 3, 4, and 5 was added to 50 mL of a tetracycline hydrochloride solution with a concentration of 20 mg / L, and placed in the dark to stir for 30 min to reach equilibrium, then 0.2 mL of H2O2 was added, and a photo-Fenton-like reaction was carried out under a xenon lamp (λ≥400 nm). Samples were taken every 10 min, filtered, and the absorbance of tetracycline hydrochloride in the supernatant was measured. The degradation of rhodamine B, ciprofloxacin, and bisphenol A was carried out as above.

[0068] Figure 3 The degradation curves of the copper hydroxyl fluoride / copper(I) oxide composite catalyst samples prepared in Examples 3, 4, and 5 for degrading tetracycline hydrochloride in a photo-Fenton-like reaction are shown in FIG. 2, Figure 3 It can be seen from FIG. 2 that the photo-Fenton-like degradation performance of the copper hydroxyl fluoride / copper(I) oxide composite catalyst prepared in the three examples is much higher than that of single copper hydroxyl fluoride, and the degradation rate of tetracycline hydrochloride by the copper hydroxyl fluoride / copper(I) oxide composite catalyst prepared in Example 3 can reach more than 99% after 40 min of reaction. This indicates that when copper(I) oxide is compounded with copper hydroxyl fluoride, H2O2 can quickly generate hydroxyl radicals with strong oxidizing properties, and in the conversion of Cu + and Cu 2+ , the synergistic effect of photocatalysis and Fenton-like effect is accelerated, and the cyclic stability of the catalyst is improved.

[0069] Table 1 shows the performance of the hydroxyl copper fluoride / cuprous oxide composite catalyst sample prepared in Example 3 in degrading different organic pollutants. The experimental results in Table 1 show that after 30 min of reaction, the degradation rate of rhodamine B can reach more than 99%; after 60 min of reaction, the degradation rate of ciprofloxacin can reach more than 78%; and after 60 min of reaction, the degradation rate of bisphenol A can reach more than 83%.

[0070] Table 1. Degradation performance of the hydroxyl copper fluoride / cuprous oxide composite catalyst prepared in Example 3

[0071]

[0072] Meanwhile, the present invention conducted corresponding degradation tests on the composite catalysts prepared in Examples 6 and 7. The experimental results showed that their degradation performance was comparable to or slightly inferior to that of Example 3.

[0073] Catalyst cycling experiment:

[0074] Weigh 10 mg of the copper hydroxyfluoride / cuprous oxide composite catalyst prepared in Example 1 of this invention, add it to 50 mL of a 20 mg / L tetracycline hydrochloride solution, and stir in the dark for 30 minutes until equilibrium is reached. Then add 0.2 mL of H2O2 and carry out a photo-Fenton-like reaction under a xenon lamp (λ≥400 nm). After the catalyst has been completely degraded, filter and measure the absorbance of tetracycline hydrochloride in the supernatant. The filtered catalyst is washed, dried, and added again to 50 mL of a 20 mg / L tetracycline hydrochloride solution for a photo-Fenton-like reaction under the same conditions. Repeat the same operation 4 times. The results are shown in [Figure 1]. Figure 4 .

[0075] from Figure 4 As can be seen, after four cycles, the degradation efficiency of tetracycline hydrochloride by the copper hydroxyfluoride / carbon nitride composite catalyst of the present invention did not decrease significantly and could still reach 97%.

[0076] In summary, the hydroxyl copper fluoride / carbon nitride composite catalyst of this invention has good catalytic degradation and catalytic stability, and has broad application prospects in the treatment of organic polluted wastewater.

Claims

1. A hydroxy-copper fluoride / cuprous oxide composite catalyst, characterized in that, The catalyst is composed of a mixture of copper hydroxyfluoride and cuprous oxide generated by its in-situ reduction. The hydroxy copper fluoride / cuprous oxide composite catalyst was prepared by the following steps: Disperse copper hydroxy fluoride in deionized water, add a reducing agent at 5~80℃ and react for 0.5~8 hours. A small amount of cuprous oxide is generated in situ on the surface of copper hydroxy fluoride. The product is then filtered, washed and dried to obtain the final product. The hydroxy copper fluoride / cuprous oxide composite catalyst is used for photo-Fenton degradation of organic pollutants such as tetracycline hydrochloride, rhodamine B, ciprofloxacin, or bisphenol A.

2. The preparation method of the hydroxyl copper fluoride / cuprous oxide composite catalyst according to claim 1, characterized in that, Includes the following steps: Copper hydroxyfluoride is dispersed in deionized water, and a reducing agent is added at a temperature of 5-80℃ for 0.5-8 hours. A small amount of cuprous oxide is generated in situ on the surface of copper hydroxyfluoride. The product is then filtered, washed, and dried to obtain the final product. The reducing agent is one or more of glucose, hydrazine hydrate, and sodium borohydride.

3. The preparation method of the hydroxyl copper fluoride / cuprous oxide composite catalyst according to claim 2, characterized in that, When the reducing agent is hydrazine hydrate, the mass-to-volume ratio of copper hydroxyfluoride to hydrazine hydrate is 1g:2.5-400μL; when the reducing agent is glucose, the mass ratio of copper hydroxyfluoride to glucose is 1g:2-13g; when the reducing agent is sodium borohydride, the mass ratio of copper hydroxyfluoride to sodium borohydride is 1g:0.001-0.05g.

4. The preparation method of the hydroxyl copper fluoride / cuprous oxide composite catalyst according to claim 2, characterized in that, The mass ratio of the copper hydroxyfluoride to deionized water is 1g:20-400g.

5. The preparation method of the hydroxyl copper fluoride / cuprous oxide composite catalyst according to claim 2, characterized in that, During the reaction, the stirring speed is 350~600 rpm.

6. The preparation method of the hydroxyl copper fluoride / cuprous oxide composite catalyst according to claim 2, characterized in that, The washing process involves washing the food 2-3 times with distilled water, followed by washing it 1-2 times with anhydrous ethanol. The drying process involves vacuum drying at 60±10℃ for 3-5 hours.

7. The application of the hydroxyl copper fluoride / cuprous oxide composite catalyst according to claim 1 in the photo-Fenton-like degradation of organic pollutants.

8. The application of the hydroxyl copper fluoride / cuprous oxide composite catalyst according to claim 7 in the photo-Fenton-like degradation of organic pollutants, characterized in that, The organic pollutant is tetracycline hydrochloride, rhodamine B, ciprofloxacin, or bisphenol A.

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