Medium-entropy anion alloy CuFe (OSC) and preparation method and application thereof

Abstract

The invention discloses a medium-entropy anion alloy CuFe (OSC) and a preparation method and application thereof.The preparation method comprises the steps that CuCl2 and thiourea are added into ethyl alcohol, the mixture is heated and stirred to be fully mixed and then dried, and Cu precursor salt is obtained; the preparation method comprises the following steps: adding FeCl3 and thiourea into ethanol, heating and stirring until the materials are fully mixed, and then drying to obtain Fe precursor salt; then Cu precursor salt and Fe precursor salt are mixed, and mixed powder is obtained; and under the air atmosphere, the mixed powder is placed in a Joule heating instrument for a reaction, and the medium-entropy anion alloy CuFe (OSC) is obtained and used for Fenton-like oxidative degradation of tetracycline. Metal Cu and Fe serve as medium-entropy alloy components, meanwhile, non-metallic elements O, S and C are supplemented for electronic regulation and control, the oxygen adsorption capacity is enhanced, more active catalytic sites are generated, accordingly, interface charge transfer is effectively accelerated, the diffusion process of pollutants is improved, and efficient degradation of tetracycline is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic materials and preparation thereof, and specifically relates to a medium-entropy anion alloy CuFe (OSC) and a preparation method thereof and application thereof in Fenton-like oxidation degradation of tetracycline. Background Art

[0002] Tetracycline antibiotics are widely used as drugs to treat human and animal diseases due to their low price, broad antibacterial spectrum and low toxic side effects. They are also used in large quantities as additives in the aquaculture industry to improve feed utilization efficiency and promote animal growth. A large amount of undegraded tetracycline is enriched in aquaculture wastewater, causing water pollution and increasing environmental and ecological risks. Therefore, there is an urgent need to develop efficient and feasible antibiotic wastewater purification technology to ensure the safety of the water environment.

[0003] At present, the technologies for tetracycline degradation mainly include chemical oxidation, photocatalysis, biodegradation, ozone oxidation, etc. Among them, the Fenton-like oxidation based on iron ions is widely used for the removal of tetracycline as an advanced oxidation technology due to its high degradation efficiency, strong operability and good environmental compatibility. However, in the Fenton-like reaction, the catalyst is prone to aggregation and corrosion at acidic pH, which reduces its catalytic activity and stability, limiting its wide application in wastewater treatment.

[0004] In the past few years, high entropy alloys have attracted widespread attention due to their superior physical and chemical properties. In particular, due to their special crystal structure and the diversity of multi-element, high entropy alloys are considered to be potential high-performance advanced catalysts. With the deepening of research, the concept of medium entropy alloys composed of three to five elements was first proposed in 2004. Compared with high entropy alloys, medium entropy alloys have better machinability, lower density and lower cost. Therefore, it is of great significance to seek a medium entropy alloy with high catalytic performance, good material stability, recyclability and no secondary pollution, and use it as a catalyst for Fenton-like oxidation degradation of tetracycline. Summary of the invention

[0005] The present invention aims to provide a medium-entropy anion alloy CuFe (OSC) and a preparation method and application thereof, wherein metal Cu and Fe are used as medium-entropy alloy components, and non-metallic elements O, S, and C are used for electronic regulation, thereby enhancing the adsorption capacity of oxygen and generating more active catalytic sites, thereby effectively accelerating interfacial charge transfer, improving the diffusion process of pollutants, and realizing efficient degradation of tetracycline.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] A method for preparing a medium entropy anion alloy CuFe (OSC), comprising the following steps:

[0008] (1) adding CuCl2 and thiourea to ethanol, heating and stirring until fully mixed, and then drying to obtain a Cu precursor salt; adding FeCl3 and thiourea to ethanol, heating and stirring until fully mixed, and then drying to obtain a Fe precursor salt;

[0009] (2) mixing a Cu precursor salt and a Fe precursor salt to obtain a mixed powder; placing the mixed powder in a Joule heating apparatus under an air atmosphere to react, thereby obtaining a medium-entropy anion alloy CuFe (OSC).

[0010] Preferably, in step (1), the molar ratio of CuCl2 to thiourea is 2-3:1, the molar ratio of FeCl3 to thiourea is 2-3:1, and the heating temperature is 50-60°C.

[0011] Preferably, in step (2), the mass ratio of the Cu precursor salt to the Fe precursor salt is 2-1:1-2; more preferably 1:1.

[0012] Preferably, in step (2), the parameters of the Joule heater are set as follows: voltage 30-40 V, current 300-350 A, reaction time 15-20 s, reaction temperature 1000-1500° C.

[0013] The definition of the medium-entropy anion alloy CuFe (OSC) described in the present invention is derived from the medium-entropy alloy, and is composed of three or four non-metallic alloy elements, which are anionic components in the medium-entropy components, making it easy to electronically control the metal alloy elements to improve their catalytic performance.

[0014] The present invention also provides a medium-entropy anion alloy CuFe (OSC) prepared by the above preparation method.

[0015] The present invention also provides the application of the medium entropy anion alloy CuFe(OSC), which is used for Fenton-like oxidation degradation of tetracycline.

[0016] The present invention uses metal Cu and Fe as medium-entropy alloy components, and simultaneously uses non-metallic elements O, S, and C for electronic regulation. The precursor is rapidly thermally decomposed by Joule heating technology, and the medium-entropy anion alloy CuFe (OSC) can be prepared in just a few seconds. Based on the joint action of Cu and Fe and the mutual influence of electronic structure, the adsorption capacity of oxygen is enhanced, and more active catalytic sites are generated, thereby effectively accelerating the interfacial charge transfer, improving the diffusion process of pollutants, and realizing the efficient degradation of tetracycline.

[0017] The advantages of the present invention are:

[0018] (1) The medium-entropy anion alloy CuFe (OSC) of the present invention, the bimetallic Cu and Fe work together, and the non-metallic elements O, S, and C are used to regulate the electrons, which more effectively accelerates the interfacial charge transfer and achieves efficient degradation of tetracycline.

[0019] (2) The medium-entropy anion alloy CuFe(OSC) of the present invention has strong magnetism, is conducive to recycling and reuse, avoids secondary pollution, and has excellent stability and photoelectrochemical properties. After multiple cycles of degradation, it can still efficiently degrade tetracycline organic wastewater.

[0020] (3) The medium-entropy anion alloy CuFe(OSC) of the present invention adopts Joule heating technology, which is fast and efficient and can be prepared in just a few seconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FT-IR spectra of different samples, where a is Cu(OSC) (Comparative Example 1), b is Fe(OSC) (Comparative Example 2), and c is CuFe(OSC) (Example 1).

[0022] Figure 2 SEM spectrum (a), HRTEM spectrum (b) and corresponding element mapping (c) of CuFe(OSC) (Example 1).

[0023] Figure 3 The molar ratio diagram of CuFe(OSC) (Example 1) calculated by ICP.

[0024] Figure 4 It is the VSM spectrum of CuFe(OSC) (Example 1).

[0025] Figure 5 : EIS spectra of different samples, a is Cu(OSC) (Comparative Example 1), b is Fe(OSC) (Comparative Example 2), and c is CuFe(OSC) (Example 1).

[0026] Figure 6 It is a Fenton-like degradation diagram of tetracycline by different samples, a is Cu(OSC) (Comparative Example 1), b is Fe(OSC) (Comparative Example 2), c is CuFe(OSC) (Example 1), d is CuFeO (Comparative Example 3), and e is CuFeOC (Comparative Example 4).

[0027] Figure 7 This is a stability investigation diagram of CuFe(OSC) (Example 1). DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with specific implementation examples.

[0029] Fenton-like degradation experiment: First, 20mL of 50mg / L tetracycline solution was added to 5 beakers respectively and its initial absorbance was measured, and then 5mg of catalyst was added respectively, and the initial temperature was 25°C. Subsequently, the magnetic stirrer (rotation speed was 600rpm / min), and after the catalyst and the pollutant reached adsorption equilibrium, 20μL of 30% H2O2 was added to the above solution to initiate the reaction. For experimental accuracy, each beaker was sampled at only one time point, and samples were taken at different time intervals. The concentration was measured by UV-visible spectrophotometer, and the degradation rate Dr was calculated by the formula: Dr=(C0-C)×100 / C0, where C0 is the concentration of tetracycline when adsorption equilibrium is reached, C is the concentration of tetracycline solution measured at time t, and t is the reaction time.

[0030] Comparative Example 1

[0031] First, 0.05 mol of CuCl2 and 0.02 mol of thiourea were weighed and added to an ethanol (50 mL) solution in turn to form a Cu salt low eutectic solvent (DESs), and the mixture was stirred continuously in an oil bath at 60°C until dry at a stirring speed of 500 rpm / min. The dried sample was collected as the Cu precursor salt. Subsequently, the Cu-based precursor salt was placed in a graphite sheet and transferred to a Joule heater for reaction. The program setting parameters in the Joule heater were a rapid heating mode with a voltage of 40 V, a current of 350 A, a reaction time of 20 s, and a reaction temperature range of 1127°C. After the reaction, the collected products were washed repeatedly with deionized water and ethanol for three times to remove residual salts. Finally, the obtained sample was vacuum dried at 40°C for 12 h and recorded as Cu(OSC).

[0032] Comparative Example 2

[0033] First, 0.05 mol of FeCl3 and 0.02 mol of thiourea were weighed and added to an ethanol (50 mL) solution in turn to form Fe salt DESs, and the mixture was stirred continuously in an oil bath at 60°C until dry at a stirring speed of 500 rpm / min. The dried sample was collected as the Fe precursor salt. Subsequently, the Fe-based precursor salt was placed in a graphite sheet and transferred to a Joule heater for reaction. The program setting parameters in the Joule heater were rapid heating mode, voltage 40 V, current 350 A, reaction time 20 s, and reaction temperature range 1127°C. After the reaction, the collected products were washed repeatedly with deionized water and ethanol for three times to remove residual salts. Finally, the obtained sample was vacuum dried at 40°C for 12 h and recorded as Fe(OSC).

[0034] Example 1

[0035] The preparation of Cu precursor salt is the same as that of Comparative Example 1, and the preparation of Fe precursor salt is the same as that of Comparative Example 2.

[0036] Firstly, the Cu precursor salt and the Fe precursor salt were mixed in equal quantities, the mixed sample was placed in a graphite sheet, and transferred to a Joule heater for reaction. The program setting parameters in the Joule heater were a rapid heating mode, a voltage of 40 V, a current of 350 A, a reaction time of 20 s, and a reaction temperature range of 1127 °C. After the reaction, the products were collected and washed repeatedly with deionized water and ethanol for three times to remove residual salts. Finally, the obtained sample was vacuum dried at 40 °C for 12 h and recorded as CuFe(OSC).

[0037] Comparative Example 3

[0038] Firstly, equal masses of CuCl2 and FeCl3 were mixed evenly, the mixed sample was placed in a graphite sheet, and transferred to a Joule heater for reaction. The program setting parameters in the Joule heater were rapid heating mode, voltage 40V, current 350A, reaction time 20s, and reaction temperature range 1127℃; after the reaction, the products were collected and washed repeatedly with deionized water and ethanol for 3 times to remove residual salt; finally, the obtained sample was vacuum dried at 40℃ for 12h and recorded as CuFeO.

[0039] Comparative Example 4

[0040] First, 0.05 mol of CuCl2 and 0.02 mol of urea were weighed and added to an ethanol (50 mL) solution in turn to form Cu salt DESs, and the mixture was stirred in an oil bath at 60 °C until dry at a stirring speed of 500 rpm / min. The dried sample was collected to obtain the Cu precursor salt. Second, 0.05 mol of FeCl3 and 0.02 mol of urea were weighed and added to an ethanol (50 mL) solution in turn to form Fe salt DESs, and the mixture was stirred in an oil bath at 60 °C until dry at a stirring speed of 500 rpm / min. min, and collect the dried sample, which is the Fe precursor salt; then, mix the Cu precursor salt and the Fe precursor salt of equal mass, put the mixed sample into a graphite sheet, and transfer it to a Joule heater for reaction. The program setting parameters in the Joule heater are the rapid heating mode, the voltage is 40V, the current is 350A, the reaction time is 20s, and the reaction temperature range is 1127℃; after the reaction, the product is collected and washed repeatedly with deionized water and ethanol for 3 times to remove residual salt; finally, the obtained sample is vacuum dried at 40℃ for 12h and recorded as CuFe(OC).

[0041] like Figure 1 As shown, for Cu(OSC), at 916 cm -1 and 466cm -1 The stretching vibration peaks of SS and Cu-O bonds were observed at the band positions at 916 cm -1 and 463cm-1 The corresponding stretching vibration peaks are also observed at the position; for Fe(OSC), 571cm -1 The peak at 584 cm-1 of CuFe(OSC) is related to the Fe–O bending vibration. -1 The corresponding peaks are also observed at , which indicates the successful preparation of CuFe(OSC) material.

[0042] like Figure 2 As shown in the SEM spectrum of CuFe(OSC), it was observed that CuFe(OSC) presented an irregular polyhedral structure, and the lattice fringe spacing of CuFe(OSC) was 0.33nm and 0.22nm, which corresponded to the (111) crystal plane and (220) crystal plane of the crystal structure, respectively; in addition, the uniform distribution of Cu, Fe, O, S and C elements in CuFe(OSC) was observed through the element mapping diagram.

[0043] like Figure 3 As shown in the molar ratio diagram calculated by ICP, Cu, Fe, O, S and C elements are included, and the molar ratio of Cu:Fe:O:S:C=7:2.2:23.7:1.3:0.8.

[0044] like Figure 4 As shown in the VSM spectrum, the saturation magnetization intensity of CuFe(OSC) is M S =16.2emu / g, it is a soft magnetic material with good magnetic separation ability.

[0045] like Figure 5 As shown, compared with Cu(OSC) and Fe(OSC), CuFe(OSC) has the smallest impedance radius, indicating that the construction of the medium-entropy anion alloy CuFe(OSC) can accelerate the rapid separation and transfer of electrons, proving its excellent photoelectrochemical performance.

[0046] like Figure 6 As shown, compared with CuFeO and CuFe(OC), CuFe(OSC) achieved a degradation rate of 80.2% within 2 minutes, proving that O, S, and C elements play an important role in regulating the performance of the material. At the same time, compared with single Cu(OSC) and Fe(OSC), CuFe(OSC) extended the degradation time to reach a degradation rate of 94.3% in 60 minutes, proving its excellent Fenton-like oxidation degradation activity.

[0047] Figure 7To investigate the stability of CuFe(OSC), in the stability experiment, after each cycle experiment, the catalyst was centrifuged and collected, washed repeatedly with deionized water several times, and then dried in a vacuum oven for the next cycle. As can be seen from the figure, CuFe(OSC) shows high stability. After five cycle experiments, the difference in degradation performance is less than 3%, indicating that the medium-entropy anion alloy CuFe(OSC) prepared by Joule heating synthesis has good stability and can be used multiple times.

Claims

1. A method for preparing a medium entropy anion alloy CuFe (OSC), characterized in that: The steps include: (1) adding CuCl2 and thiourea to ethanol, heating and stirring until fully mixed, and then drying to obtain a Cu precursor salt; adding FeCl3 and thiourea to ethanol, heating and stirring until fully mixed, and then drying to obtain a Fe precursor salt; (2) mixing a Cu precursor salt and a Fe precursor salt to obtain a mixed powder; placing the mixed powder in a Joule heating apparatus under an air atmosphere to react, thereby obtaining a medium-entropy anion alloy CuFe (OSC).

2. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of CuCl2 to thiourea is 2-3:1, the molar ratio of FeCl3 to thiourea is 2-3:1, and the heating temperature is 50-60°C.

3. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of the Cu precursor salt to the Fe precursor salt is 2-1:1-2.

4. The preparation method according to claim 3, characterized in that: In step (2), the mass ratio of the Cu precursor salt to the Fe precursor salt is 1:

1.

5. The preparation method according to claim 1, characterized in that: In step (2), the parameters of the Joule heating device are set as follows: voltage 30-40 V, current 300-350 A, reaction time 15-20 s, reaction temperature 1000-1500° C.

6. The medium-entropy anion alloy CuFe (OSC) obtained by the preparation method according to any one of claims 1 to 5.

7. The use of the medium entropy anion alloy CuFe (OSC) according to claim 6, characterized in that: It was used for Fenton-like oxidation degradation of tetracycline.

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