A high-entropy spinel ferrite catalyst capable of efficiently degrading dyes and antibiotics, and a preparation method and application thereof

Abstract

The application discloses a high-efficiency degradation of dyes and antibiotics high-entropy spinel ferrite catalyst and a preparation method and application thereof. 1 / 2 Zn 1 / 2 Fe 2 / 3Co 2 / 3 Ni 2 / 3 O4(HEO-FNCCZ) high-entropy spinel ferrite catalyst, the photocatalytic degradation performance of common dyes and antibiotics is evaluated by using simulated visible light photocatalysis, and the reaction mechanism of the photocatalytic degradation of methylene blue with the best effect is studied. The catalytic effect of the spinel ferrite is utilized to effectively promote the photocatalytic reaction, so that the environment-friendly pollutant degradation is realized. The method has the characteristics of simple production process, no introduction of various organic toxic and harmful substances, non-toxic and harmless in use, catalyst recovery efficiency more than 95%, and no secondary pollution. The preparation method only involves processes such as dissolving, calcining and crushing, and is extremely suitable for industrialized batch production.

Description

Technical Field

[0001] This invention relates to the fields of photocatalysis, spinel ferrite, and pollutant degradation, specifically to a high-entropy spinel ferrite catalyst for the efficient degradation of dyes and antibiotics, its preparation method, and its applications. Background Technology

[0002] Industrial wastewater contains large amounts of dyes and antibiotics, causing serious pollution and even threatening human survival and health when discharged into the environment. Methylene blue (MB), a commonly used chemical dye in textile industry wastewater, has azo and nitro groups and other difficult-to-decompose chemical structures, exhibiting carcinogenicity and toxicity. Combined with the inhibitory effect of antibiotics on microorganisms, traditional processes are difficult to remove effectively, usually requiring advanced oxidation technologies to degrade methylene blue into harmless products. Cefixime and tetracycline, as commonly used drugs, are widely used to treat bacterial infections in humans and animals, and their associated environmental risks have threatened human health. The effective removal of antibiotics from aquatic ecosystems has attracted increasing attention. However, in treated wastewater, antibiotic levels are often as low as 10 ppm, and low concentrations of antibiotics are difficult to remove using conventional methods such as membrane filtration, adsorption, and electrochemistry. In recent years, photocatalysis technology has been considered a promising method for degrading pollutants due to its advantages such as no secondary pollution risk, environmental sustainability, and environmentally friendly degradation performance.

[0003] In the past, oxides based on transition metals (Fe, Co, Ni) have been studied as alternative catalysts to noble metals due to their abundance, low cost, and high catalytic activity. Among them, spinel ferrites have attracted much attention due to their advantages such as high catalytic efficiency, simple preparation, and easy recycling. For example, the low-cost spinel ferrite Fe3O4 has been widely reported to have photocatalytic activity and has been applied to the photocatalytic degradation of dyes. In addition, its excellent stability and magnetism are beneficial for the recycling of wastewater through photocatalytic degradation. However, due to the large specific surface area and narrow spectral response of Fe3O4, its photocatalytic performance is still not ideal.

[0004] Therefore, based on the high-entropy oxide theory, preparing high-entropy spinel ferrites to enhance their photocatalytic activity is a promising strategy. Summary of the Invention

[0005] To solve the above problems, the technical solution of the present invention is: a method for preparing a high-entropy spinel ferrite catalyst for efficiently degrading dyes and antibiotics, comprising the following steps:

[0006] Weigh ferric nitrate, nickel nitrate, cobalt nitrate, zinc acetate, and copper nitrate in a molar ratio of 1:1:1:0.76:0.76, dissolve and mix them in deionized water to obtain a metal ion salt solution.

[0007] Weigh out glycine in a molar ratio of 1.05:1.04 to metal ions; weigh out citric acid in a molar ratio of 1.09:1.04 to metal ions. Dissolve citric acid and glycine in the metal ion salt solution and stir until a colloidal solution is obtained.

[0008] The colloidal solution was transferred to an evaporating dish and heated and stirred continuously. After spontaneous combustion, stirring was stopped, and the mixture was allowed to cool naturally after combustion to obtain the precursor powder.

[0009] The precursor powder was ground and then calcined in a high-temperature furnace at 700–900°C to obtain a high-entropy spinel ferrite catalyst.

[0010] Furthermore, the precursor powder is ground and then calcined in a high-temperature furnace at 800°C to obtain a high-entropy spinel ferrite catalyst.

[0011] Furthermore, the colloidal solution is evaporated in an evaporating dish for 30 min to 2 h at an evaporation temperature of 400℃ to 500℃; the stirring speed is 30 rpm.

[0012] Furthermore, the heating rate during calcination is 5℃ / min, the cooling rate is 5℃ / min, and the holding time is 2h.

[0013] Furthermore, the general formula of the high-entropy spinel ferrite catalyst is Cu. 1 / 2 Zn 1 / 2 Fe 2 / 3 Co 2 / 3 Ni 2 / 3 O4, wherein the catalyst particles have a size of 50-200 nm.

[0014] The high-entropy spinel ferrite catalyst described herein degrades antibiotics without the addition of oxidants under light irradiation conditions, and the antibiotics include tetracycline and cefixime.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The present invention provides a method for enhancing the ability of spinel ferrite to degrade dyes and antibiotics under visible light using a high-entropy strategy:

[0017] (1) In this study, Cu was successfully prepared by the sol-combustion method. 1 / 2 Zn 1 / 2 Fe 2 / 3 Co 2 / 3 Ni 2 / 3 O4 high-entropy spinel ferrite catalyst exhibits significant selective photocatalytic activity for dyes such as methylene blue, and also shows some photocatalytic activity for antibiotics such as tetracycline and cefixime, with a degradation efficiency significantly higher than that of single-component oxides.

[0018] (2) The catalyst maintains good photocatalytic activity after multiple cycles, with a cycle performance of 96.63%.

[0019] (3) By adopting a high-entropy strategy, a variety of metal elements are combined to form a high-entropy spinel ferrite catalyst, which makes full use of the high-entropy effect, strong lattice distortion effect, slow diffusion effect and cocktail effect, and significantly improves the photocatalytic performance of the catalyst.

[0020] (4) High-entropy spinel ferrite catalysts contain metal ions in multiple valence states, which provide more reaction sites and charge transfer pathways for catalytic reactions, further improving catalytic activity.

[0021] (5) This invention uses visible light as an energy source, avoiding the secondary pollution problems that may occur in traditional chemical oxidation methods. The high-entropy spinel ferrite catalyst has good magnetic properties, is easy to recycle, and conforms to the concept of green environmental protection.

[0022] (6) The high-entropy spinel ferrite catalyst is prepared by sol-gel combustion method. The operation is simple, the cost is low, and it is easy to achieve large-scale production. Attached Figure Description

[0023] Figure 1 In the middle (a), XRD patterns of spinel oxides J-700, J-800, and J-900 synthesized under different conditions and their corresponding spinel ferrite standard cards are shown, and (bc) are SEM images of high-entropy spinel oxide J-800.

[0024] Figure 2 Concentration changes of different pollutants for photocatalytic degradation C t / C0 figure, a is methylene blue (MB), b is rhodamine B (RhB), c is eosin, d is tetracycline, e is cefixime, f is a summary of the degradation rates of the five pollutants;

[0025] Figure 3 a. Represents cycle performance test; b. Represents photocatalytic degradation of methylene blue by high-entropy spinel oxide catalyst and single-element oxide catalyst; c. Represents pseudo-first-order kinetics of photocatalytic degradation.

[0026] Figure 4 For four groups (Co) 0.4 Ni 0.2 Zn 0.2 Cu 0.2 Fe2O4 powder has almost no catalytic degradation effect on TCH in the absence of light and persulfate (PDS). Detailed Implementation

[0027] The present invention will be further described below with reference to embodiments and accompanying drawings. However, the following description is only for some exemplary examples of the present invention and is used only to illustrate the present invention, and is not intended to limit the scope of the present invention.

[0028] Example 1

[0029] A high-entropy spinel ferrite catalyst for the efficient degradation of dyes and antibiotics, and its preparation method, comprising the following steps:

[0030] Accurately weigh 0.023 mol Fe(NO3)3·9H2O (ferric nitrate nonahydrate), 0.023 mol Ni(NO3)2·6H2O (nickel nitrate hexahydrate), 0.023 mol Co(NO3)2·6H2O (cobalt nitrate hexahydrate), 0.0175 mol Zn(C2H3O2)2·2H2O (zinc acetate dihydrate), and 0.0175 mol Cu(NO3)2·3H2O (copper nitrate trihydrate). After thorough mixing and dissolution, a metal salt solution is obtained. In this example, Zn(C2H3O2)2·2H2O (zinc acetate dihydrate) is selected for precise weighing. Weighing Zn((NO3)2*6H2O) is more accurate and has less error because Zn((NO3)2*6H2O is hygroscopic and its melting point is close to room temperature, making it difficult to weigh accurately. Accurately weigh 0.109 mol of citric acid and 0.105 mol of glycine, dissolve them completely at 70℃, stir for 1 hour, then add the metal salt solution and mix thoroughly. In this example, the pH of the mixed solution is 4.00–7.00. Stir for 6 hours to obtain a colloidal solution. Transfer the colloidal solution to an evaporating dish, continue heating and stirring until spontaneous combustion occurs, then stop stirring and allow it to cool naturally after combustion to obtain the precursor powder. The precursor powder (Cu) 1 / 2 Zn 1 / 2 Fe 2 / 3 Co 2 / 3 Ni 2 / 3 ) x O y The precursor powder was ground and then calcined in a high-temperature furnace. The precursor powder was calcined at three different temperatures—700℃, 800℃, and 900℃—for 2 hours each, yielding the product Cu. 1 / 2 Zn 1 / 2 Fe 2 / 3 Co 2 / 3 Ni 2 / The products calcined at different temperatures were named J-700, J-800, and J-900, respectively.

[0031] In this embodiment, Cu 2+ Zn 2+ Fe 3+ Co 3+ Ni 3+The molar ratio of the salt ions is the same as the stoichiometric ratio of the divalent and trivalent metal ions in the general chemical formula of spinel, M3O4. The stoichiometric ratio of the divalent and trivalent metal ions is 1:2, with the same stoichiometric ratio for each divalent metal ion and the same stoichiometric ratio for each trivalent metal ion. Therefore, the metal salt solution contains five metal ions: Fe... 3+ Ni 3+ Co 3+ Zn 2+ Cu 2+ The molar ratio is 1.00:1.00:1.00:0.76:0.76.

[0032] In aqueous solution, citric acid can lose protons from its carboxyl and hydroxyl groups. The three carboxyl groups and one or more hydroxyl groups of citric acid can coordinate with metal ions in various ways, forming complexes with different compositions and charge states. After citric acid coordinates with metal ions by deprotonating its α-alkoxy and α-carboxyl groups, the number of protons on the β-carboxyl group can be adjusted by regulating the pH of the solution. This produces citric acid-metal ion anionic structures with different charges, thereby controlling the composition of the subsequently formed oxides. Appropriately lowering the pH increases the citric acid concentration, promoting the reversible reaction towards the formation of coordination compounds, and also facilitates the formation of citric acid-metal ion anionic structures with different charges, aiding in the nucleation of crystals in the subsequent auto-combustion process. Insufficient citric acid makes it difficult to form enough coordination compounds and may result in insufficient calorific value, potentially lowering the reaction temperature. Specifically, in this example, 1 mol of citric acid is required to form a complex with 1 mol of Fe(NO3)3, Ni(NO3)2, Co(NO3)2, Zn(C2H3O2)2, and Cu(NO3)2.

[0033] Therefore, the molar percentages of the five components in the metal salt solution are as follows: Fe(NO3)3*9H2O: 7.233%, Ni(NO3)2*6H2O: 7.233%, Co(NO3)2*6H2O: 7.233%, Zn(C2H3O2)2*2H2O: 5.503%, and Cu(NO3)2*3H2O: 5.503%. The molar percentage of glycine is 33.019%, and the ratio of glycine to metal ions is 1.05:1.04; the molar percentage of citric acid is 34.277%, and the ratio of citric acid to metal ions is 1.09:1.04.

[0034] This embodiment utilizes citric acid to complex Fe... 3+ Ni 3+ Co 3+ Zn 2+ Cu 2+Through a self-propagating combustion reaction between glycine, citric acid, and nitric acid, Fe(NO3)3, Ni(NO3)2, Co(NO3)2, Zn(C2H3O2)2, and Cu(NO3)2 decompose into N2, CO2, H2O, and metal oxides. The reaction releases a large amount of heat. The reaction process takes place in a mixed solution, ensuring the accuracy of the stoichiometry and the homogeneity of the product composition. This allows the oxides to crystallize directly from the precursor mixture. The large amount of gas generated in the reaction not only prevents contact between particles but also facilitates the rapid diffusion of the heat generated, thus preventing sintering of the products and reducing the likelihood of hard agglomeration. Organic compounds with strong complexing forces with metal ions are selected for the mixed solution to prevent the precipitation of any component crystals during combustion and volatilization, which would disrupt the overall homogeneity.

[0035] The reaction equations for the reactions of Fe(NO3)3, Ni(NO3)2, Co(NO3)2, Zn(C2H3O2)2, and Cu(NO3)2 with citric acid (C6H8O7) and O2 to produce Fe2O3, Ni2O3, Co2O3, ZnO, and CuO are as follows:

[0036] 4Fe(NO3)3 + 6C6H8O7 + 12O2 → 2Fe2O3 + 36CO2 + 24H2O + 6N2; The ratio of citric acid to metal salt is 1.5;

[0037] 4Ni(NO3)2 + 6C6H8O7 + 18O2 → 2Ni2O3 + 36CO2 + 24H2O + 4N2; The ratio of citric acid to metal salt is 1.5.

[0038] 4Co(NO3)2 + 6C6H8O7 + 18O2 → 2Co2O3 + 36CO2 + 24H2O + 4N2; The ratio of citric acid to metal salt is 1.5.

[0039] 4Zn(C2H3O2)2 + 2C6H8O7 + 25O2 → 4ZnO + 28CO2 + 20H2O; The ratio of citric acid to metal salt is 0.5.

[0040] 4Cu(NO3)2 + 6C6H8O7 + 17O2 → 4CuO + 36CO2 + 24H2O + 4N2; The ratio of citric acid to metal salt is 1.5.

[0041] Theoretically, when the five metal ions are made into a high-entropy material according to the molar ratio in the high-entropy material of this embodiment, when the weighted ratio of citric acid to metal salt is 1.33, the metal salt can be completely decomposed and impurities reduced.

[0042] The reaction equations for the reactions of Fe(NO3)3, Ni(NO3)2, Co(NO3)2, Zn(C2H3O2)2, and Cu(NO3)2 with glycine (NH2-CH2-COOH) to produce Fe2O3, Ni2O3, Co2O3, ZnO, and CuO are as follows:

[0043] 2Fe(NO3)3 + 6NH2CH2COOH + 6O2 → Fe2O3 + 12CO2 + 6N2 + 15H2O; The ratio of glycine to metal salt is 3;

[0044] 2Ni(NO3)2 + 2NH2CH2COOH → Ni2O3 + 4CO2 + 3N2 + 5H2O; The ratio of glycine to metal salt is 1;

[0045] 2Co(NO3)2 + 2NH2CH2COOH → Co2O3 + 4CO2 + 3N2 + 5H2O; The ratio of glycine to metal salt is 1.

[0046] 2Zn(C2H3O2)2+4NH2CH2COOH+17O2→2ZnO+16CO2+2N2+16H2O; The ratio of glycine to metal salt is 2;

[0047] Cu(NO3)2 + 2NH2CH2COOH + 2O2 → CuO + 4CO2 + 2N2 + 5H2O; The ratio of glycine to metal salt is 2;

[0048] Theoretically, when the five metal ions are made into a high-entropy material according to the molar ratio in the high-entropy material of this embodiment, the weighted ratio of glycine to metal salt is 1.78, which can completely decompose the metal salt and reduce impurities.

[0049] This embodiment mainly utilizes the citric acid complexation of Fe... 3+ Ni 2+ Co 2+ Zn 2+ Cu 2+ Adding glycine assists citric acid and nitrate in a self-propagating combustion reaction, which completely decomposes Fe(NO3)3, Ni(NO3)2, Co(NO3)2, Zn(C2H3O2)2, and Cu(NO3)2 into N2, CO2, H2O, and metal oxides, thereby reducing impurities.

[0050] Results Analysis: Characterization of catalysts J-700, J-800 and J-900

[0051] The results show that high-entropy spinel ferrite HEO-FNCCZ can be successfully prepared by calcination at 800℃ or 900℃. The characteristic diffraction peaks at 30.3°, 35.7°, 43.7°, 57.3° and 62.9° correspond to the (220), (311), (400), (511) and (440) crystal planes of cubic Fe3O4, respectively. Figure 1 Figure (a) shows the phase composition of spinel oxides J-700, J-800, and J-900 synthesized under different conditions. By comparing with the standard card PDF#26-1136 for spinel Fe3O4, it can be found that the XRD characteristic peaks show that J-800 and J-900 have formed high-entropy ferrites, while some characteristic peaks of J-700 are unclear, indicating the presence of obvious impurities. Figure 1 The (bc) SEM (J-800) images show that the synthesized catalyst has a uniform particle size of approximately 50-200 nm. No obvious agglomeration was observed, indicating that the material has good dispersibility, laying the foundation for subsequent performance improvements.

[0052] Example 2

[0053] A high-entropy spinel ferrite catalyst for the efficient degradation of dyes and antibiotics, and its preparation method, comprising the following steps:

[0054] Accurately weigh 0.023 mol Fe(NO3)3*9H2O (ferric nitrate nonahydrate), 0.023 mol Ni(NO3)2*6H2O (nickel nitrate hexahydrate), 0.023 mol Co(NO3)2*6H2O (cobalt nitrate hexahydrate), 0.0175 mol Zn(C2H3O2)2*2H2O (zinc acetate dihydrate), and 0.0175 mol Cu(NO3)2*3H2O (copper nitrate trihydrate). After thorough mixing and dissolution, a metal salt solution is obtained. Accurately weigh 0.109 mol citric acid and 0.105 mol glycine, dissolve them thoroughly at 60℃-80℃, and stir for 1 hour. Then add the metal salt solution and mix thoroughly. Stir for 6 hours to obtain a colloidal solution. Transfer the colloidal solution to an evaporating dish and continue heating and stirring until spontaneous combustion occurs. Stop stirring and allow it to cool naturally after combustion is complete to obtain the precursor powder (Cu). 1 / 2 Zn 1 / 2 Fe 2 / 3 Co 2 / 3Ni 2 / 3 ) x O y The precursor powder was ground and calcined in a high-temperature furnace. The precursor powder was calcined at three different temperatures (700℃, 800℃, and 900℃) for 2 hours each to obtain the catalyst Cu. 1 / 2 Zn 1 / 2 Fe 2 / 3 Co2 / 3 Ni 2 / 3 O4.

[0055] Weigh 50 mg of catalyst and pour it into a quartz glass reaction flask (quartz glass allows light to penetrate and reach the reaction system; it does not react with the reactants, ensuring the purity and controllability of the reaction). Add 100 ml of the 10 ppm concentration of the solution to be degraded and shake well. Place the reaction flask in a dark chamber for static adsorption for 12 hours, then transfer it to a photocatalytic device (PerfectLight, PCX50CDiscover) for photocatalytic reaction. Stirring is activated simultaneously. The photocatalytic degradation process and sampling are carried out in a constant temperature circulating water environment at 25℃. Take 3-4 mL of the test solution every hour. Methylene blue, rhodamine B, eosin, and tetracycline are measured using ultraviolet spectrophotometry. The test solution is sampled using a Shimadzu UV-1900i spectrometer with a scanning width of 400-800 nm. Cefixime is sampled using an Agilent 1260 Infinity II liquid chromatograph with a 258 nm spectrum. The pollutant concentration change C is obtained. t / C0.

[0056] Results Analysis: Effect of Calcination Temperature on the Photocatalytic Degradation Performance of the Catalyst

[0057] This experiment selected three commonly used industrial dyes—methylene blue (MB), rhodamine B (RhB), and eosin—and two antibiotics—tetracycline and cefixime—as degradation substrates to investigate the photocatalytic performance of HEO-FNCCZ. The experimental results are as follows: Figure 2 As shown in Figure 'af', the photocatalytic degradation efficiencies of J-700, J-800, and J-900 exhibited similar trends for each substrate. On the one hand, all three showed a decrease in catalytic degradation rate with increasing reaction time as substrate concentration decreased. On the other hand, in each experimental group, J-800 demonstrated superior photocatalytic degradation performance. For example, in the photocatalytic degradation experiment of methylene blue, where the best effect was observed, the C0.05 of the J-800 group was significantly higher after 7 hours. t The CO concentration was 5.81% lower than that of the J-700 group. Experimental results on photocatalytic degradation of dyes showed that the high-entropy spinel catalyst had a significant selective catalytic degradation effect on dyes, with the highest efficiency in the degradation of methylene blue. After 6 and 7 hours of visible light irradiation, the MB concentration in water decreased to 6.16% and 3.25%, respectively. The catalyst did not show a significant photocatalytic degradation effect on rhodamine B and eosin. Experimental results on photocatalytic degradation of antibiotics showed that the high-entropy spinel catalyst had a good photocatalytic degradation effect on tetracycline and cefixime. After 6 hours of visible light irradiation, the concentrations of tetracycline and cefixime decreased to 34.4% and 19.0% of their initial concentrations, respectively.

[0058] Example 3

[0059] Accurately weigh 0.023 mol Fe(NO3)3*9H2O (ferric nitrate nonahydrate), 0.023 mol Ni(NO3)2*6H2O (nickel nitrate hexahydrate), 0.023 mol Co(NO3)2*6H2O (cobalt nitrate hexahydrate), 0.0175 mol Zn(C2H3O2)2*2H2O (zinc acetate dihydrate), and 0.0175 mol Cu(NO3)2*3H2O (copper nitrate trihydrate). After thorough mixing and dissolution, a metal salt solution is obtained. Accurately weigh 0.109 mol citric acid and 0.105 mol glycine, and dissolve them thoroughly at 70 °C. After stirring for 1 h, add the metal salt solution and mix thoroughly. Stir for 6 h to obtain a colloidal solution. Transfer the colloidal solution to an evaporating dish and continue heating and stirring. After spontaneous combustion, stop stirring and allow it to cool naturally after combustion is complete to obtain the precursor powder. The precursor powder was ground and calcined in a high-temperature furnace. The precursor powder was calcined at three temperatures (700℃, 800℃, and 900℃) for 2 hours each to obtain the catalyst. A single-element oxide, MxOy (M = Fe, Co, Ni, Cu, Zn), was synthesized using the same combustion process, and photocatalytic degradation experiments were conducted under the same reaction conditions. 50 mg of the high-entropy catalyst and the single-oxide catalyst were weighed and poured into quartz glass reaction flasks. 100 ml of a 10 ppm solution to be degraded was added to each flask and the mixture was shaken well. The reaction flasks were allowed to stand in a dark chamber for 12 hours for adsorption, and then transferred to a photocatalytic device (PerfectLight, PCX50CDiscover) for photocatalytic reaction. Stirring was activated. The photocatalytic degradation process and sampling were carried out in a constant-temperature circulating water environment at 25℃. 4-5 mL of the test solution was taken every hour. Methylene blue was measured using ultraviolet spectrophotometry. The test solution was sampled using a Shimadzu UV-1900i spectrometer, and the absorbance A at the maximum absorption peak was obtained by acquiring the ultraviolet-visible spectrum within the scanning width range of 400-800 nm. t The same method was used to collect the standard solution, and the maximum absorbance A0 at the initial concentration was obtained. At time t, the residual amount of pollutant was C. t / C0.

[0060] The formula is as follows:

[0061] (C t / C0)×100%=A t / εb / C0=(A t / A0)×100%

[0062] C0: Initial concentration, C t Real-time concentration, A t: Absorbance, b: wavelength, ε: molar absorptivity;

[0063] Results Analysis: Comparison of photocatalytic effects between high-entropy catalysts and single oxides using methylene blue as a substrate.

[0064] High-entropy catalysts exhibit significantly better photocatalytic degradation performance than single-element oxides, with J-800 showing the best performance at 7 hours of degradation. t / C0 reached 3.25%, compared to the worst-performing Fe2O3 at 7h C t / C0 was 40.38%, representing a performance improvement of 38.29%. Other groups showed the following C values ​​for CuO at 7 hours. t / C0 is 19.85%, ZnO at 7h C t / C0 is 7.05%, and Co3O4 has a C content of 7h. t The CO content was 31.94%. On the other hand, in the photocatalytic degradation experiment, the catalyst used was 50 mg each time. The molecular weight of the high-entropy catalyst was 244.12, while that of Fe2O3 was 159.7. For the same mass, the catalyst molar ratio was 0.6542, meaning that the photocatalytic degradation performance of methylene blue per mole of high-entropy catalyst was 58.53% higher than that per mole of Fe2O3. For example... Figure 3 As shown in Figure a, the cyclic performance of the catalyst was verified by recovering and repeating the photocatalytic degradation of methylene blue. After the fourth cycle, the C1 of the catalyst for degrading methylene blue was [value missing]. t The C0 value decreased from 0.0741 to 0.0716, and the cycle performance reached 96.63%, indicating that the high-entropy ferrite catalyst has excellent cycle performance. Kinetic analysis of the photocatalytic degradation of methylene blue is as follows: Figure 3 As shown in bc, the specific data is shown in Table 1.

[0065] The approximate rate equation for the first-order reaction kinetics at the liquid-solid interface, Langmuir-Hinshelwood (LH), is as follows:

[0066]

[0067] Where t is the illumination time, and K is the apparent constant. app K is a fundamental kinetic parameter for different photocatalysts. The LH model was used to calculate the K value of methylene blue degradation rate under different conditions. app and regression coefficient R 2 R 2 A value greater than 0.95 indicates that the LH equation is applicable to the photocatalytic degradation of methylene blue, ln(C t The curve / C0) shows a good linear relationship with the t curve.

[0068] Table 1. Kinetic data of photocatalytic degradation of methylene blue by the catalyst

[0069]

[0070] Comparative Example 3

[0071] According to (Co) 0.4 Ni 0.2 Zn 0.2 Cu 0.2 The stoichiometric ratio of Fe₂O₄ was used to prepare the mixture (i.e., 0.4:0.2:0.2:0.2:2, x = 0.4). Cobalt nitrate, nickel nitrate, zinc nitrate, copper nitrate, and ferric nitrate were weighed out and mixed with distilled water. Additionally, glycine was added according to the chemical equation for complete combustion, with a molar ratio of nitrate ions to glycine of 2.5:1. The mixture was stirred until completely dissolved, yielding a mixed solution. The pH of the mixed solution was adjusted to 4.7 with ammonia water to obtain a precursor solution. The precursor solution was transferred to a quartz crucible and heated on an electric furnace to evaporate the water and eventually induce combustion, yielding precursor powder. The obtained precursor powder was placed in a muffle furnace and held at 1100℃ for 3 hours for heat treatment to obtain a tetroxide (Co) 0.4 Ni 0.2 Zn 0.2 Cu 0.2 Fe2O4 powder was used to test its ability to degrade antibiotics. The results are as follows: Figure 4 As shown. The reaction process is as follows: 240 mL of tetracycline hydrochloride solution (TCH, concentration 50 mg / L) was measured, and the four components (Co) were added. 0.4 Ni 0.2 Zn 0.2 Cu 0.2 The Fe2O4 powder concentration is 0.5 g / L. The removal rate (Rev(%)) of the simulated target pollutant TCH can be calculated using the following formula:

[0072] Rev(%) = (1―C t / C0)×100%=(1―A t / A0)×100%#(1)

[0073] Where C t C0 represents the concentration of organic pollutants in the filtrate at a certain moment; A represents the initial concentration of organic pollutants. t A0 represents the absorbance at the maximum absorption wavelength of organic pollutants in the filtrate at a certain moment (the characteristic absorption peak of tetracycline hydrochloride is 359 nm); A0 represents the absorbance at the initial maximum absorption wavelength of organic pollutants. From Figure 4 It can be seen from the four groups of elements (Co) 0.4 Ni 0.2 Zn 0.2 Cu 0.2Fe2O4 powder showed almost no catalytic degradation effect on TCH in the absence of light and persulfate (PDS), but under light, it showed some photocatalytic degradation effect on TCH, but the effect was poor and still lower than the photocatalytic degradation effect of tetracycline by the high-entropy spinel catalyst in Example 2.

Claims

1. A method for preparing a high-entropy spinel ferrite catalyst for efficiently degrading dyes and antibiotics, characterized in that, Includes the following steps: Weigh ferric nitrate, nickel nitrate, cobalt nitrate, zinc acetate, and copper nitrate in a molar ratio of 1:1:1:0.76:0.76, dissolve and mix them in deionized water to obtain a metal ion salt solution. Weigh out glycine in a molar ratio of 1.05:1.04 to metal ions; weigh out citric acid in a molar ratio of 1.09:1.04 to metal ions. Dissolve citric acid and glycine in the metal ion salt solution and stir until a colloidal solution is obtained. The colloidal solution was transferred to an evaporating dish and heated and stirred continuously. After spontaneous combustion, stirring was stopped and the mixture was allowed to cool naturally after combustion to obtain the precursor powder. The precursor powder was ground and then calcined in a high-temperature furnace at 700–900°C to obtain a high-entropy spinel ferrite catalyst.

2. The method for preparing a high-entropy spinel ferrite catalyst for efficiently degrading dyes and antibiotics according to claim 1, characterized in that, The precursor powder was ground and then calcined in a high-temperature furnace at 800°C to obtain a high-entropy spinel ferrite catalyst.

3. The method for preparing a high-entropy spinel ferrite catalyst for efficiently degrading dyes and antibiotics according to claim 1, characterized in that, The colloidal solution was evaporated in an evaporating dish for 30 min-2 h at a temperature of 400℃-500℃, and the stirring speed was 30 rpm.

4. The method for preparing a high-entropy spinel ferrite catalyst for efficiently degrading dyes and antibiotics according to claim 1, characterized in that, The heating rate during calcination is 5℃ / min, the cooling rate is 5℃ / min, and the holding time is 2h.

5. The high-entropy spinel ferrite catalyst for efficiently degrading dyes and antibiotics prepared by the method according to claim 1, characterized in that, The general formula of the high-entropy spinel ferrite catalyst is Cu. 1 / 2 Zn 1 / 2 Fe 2 / 3 Co 2 / 3 Ni 2 / 3 O4, wherein the catalyst particles have a size of 50-200 nm.

6. The application of the high-entropy spinel ferrite catalyst as described in claim 5 in the degradation of antibiotics under light irradiation without the addition of an oxidant.

7. The application as described in claim 6, characterized in that, The antibiotics include tetracycline and cefixime.

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