Metal organic framework composite material rich in sulfur vacancies, preparation method thereof and ofloxacin photocatalytic degradation catalyst

Abstract

The invention relates to the technical field of environment-friendly materials, in particular to a metal organic framework composite material rich in sulfur vacancies, a preparation method of the metal organic framework composite material and an ofloxacin photocatalytic degradation catalyst. On the basis of the current research situation of a heterogeneous photo-Fenton reaction system, MIL-88A, soluble Zn salt, soluble In salt and thioacetamide are used as raw materials, and the metal organic framework composite material rich in sulfur vacancies, which is high in photocatalytic activity, high in degradation efficiency and high in repeated utilization rate, is prepared. The prepared metal organic framework composite material rich in sulfur vacancies is applied to a visible light and H2O2 reaction system, photocatalytic degradation of ofloxacin is achieved, and the technical defect that ofloxacin degradation cannot be achieved through a traditional MIL-88A at ZnIn2S4 composite material is overcome.

Description

Technical Field

[0001] The invention relates to the technical field of environmentally friendly materials, in particular to a metal organic framework composite material rich in sulfur vacancies and a preparation method thereof, and an ofloxacin photocatalytic degradation catalyst. Background Art

[0002] With the improvement of living standards, the water environment pollution caused by ofloxacin in medicines and personal care products has become increasingly prominent. In recent years, the treatment technology of ofloxacin wastewater is still a hot topic in the field of environmental protection. Due to the presence of piperazine rings, quinolone rings and fluorine atoms with relatively stable chemical properties, ofloxacin is not easy to break and decompose chemical bonds in some common degradation technologies. Compared with some other antibiotics, such as tetracyclines, sulfonamides, β-lactam antibiotics, etc., it has a more stable molecular structure and chemical properties, so it is more difficult to degrade.

[0003] The Fenton reaction has the advantages of strong oxidation ability, fast reaction rate, electrophilicity, mild reaction process and low selectivity, and is relatively easy to apply industrially. It is widely used in the removal of difficult-to-degrade organic pollutants. In addition, the iron ions in the Fenton reaction undergo hydration to form complex complex substances, which play a good flocculation role and can effectively remove suspended solid particles in sewage to further improve the sewage purification capacity. However, the removal effect and practical application of traditional iron-based homogeneous Fenton reaction on pollutants are affected and limited by many factors, mainly: the applicable pH range is narrow, and the optimal operating pH is 3.0; the catalyst cannot be recycled and reused; a large amount of iron sludge is generated, causing secondary pollution; the utilization rate of H2O2 is not high; Fe 2+ It is difficult to control the dosage.

[0004] It can be seen that the traditional Fenton oxidation technology has many of the above shortcomings, and the heterogeneous photo-Fenton reaction, which is an improved and developed Fenton reaction, has stronger catalytic ability, wider pH range, simpler operation process, and better reusability, and has become a research hotspot for advanced oxidation technology at home and abroad. Although some progress has been made after years of research, the heterogeneous photo-Fenton reaction still faces several prominent problems when it is used, specifically: (1) low apparent quantum efficiency; (2) easy recombination of photogenerated electron-hole pairs.

[0005] The prior art discloses MIL-88A, which is used as a carrier of a supported heterogeneous catalyst, and has the advantages of high specific surface area, porous structure, good chemical stability, adjustable pore size, and the ability to effectively disperse active components; the prior art discloses ZnIn2S4, which is used as a transition metal ion-containing catalyst, and has the advantages of a wide visible light response range, good chemical stability, a unique crystal structure that is conducive to electron transport, and adjustable element composition; based on the advantages of the two, the prior art prepares a MIL-88A@ZnIn2S4 composite material. However, the obtained MIL-88A@ZnIn2S4 composite material cannot achieve the degradation of ofloxacin due to the limited number of reactive active sites, low charge separation efficiency, and unstable photocatalytic performance. Summary of the invention

[0006] In view of the deficiencies in the above-mentioned prior art, the present invention provides a metal-organic framework composite material rich in sulfur vacancies, a preparation method thereof, and a catalyst for photocatalytic degradation of ofloxacin. The present invention uses MIL-88A, a soluble Zn salt, a soluble In salt, and thioacetamide as raw materials to prepare a metal-organic framework composite material rich in sulfur vacancies with strong photocatalytic activity, high degradation efficiency, and high reuse rate. The metal-organic framework composite material rich in sulfur vacancies is a MIL-88A@ZnIn2S4 composite material rich in sulfur vacancies. The prepared metal-organic framework composite material rich in sulfur vacancies is applied to a visible light and H2O2 reaction system to achieve photocatalytic degradation of ofloxacin, thereby solving the technical defect that the traditional MIL-88A@ZnIn2S4 composite material cannot achieve ofloxacin degradation.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] The method for preparing a metal organic framework composite material rich in sulfur vacancies comprises the following steps:

[0009] MIL-88A is dispersed in deionized water, and then soluble Zn salt, soluble In salt and thioacetamide are added thereto. After mixing evenly, a hydrothermal reaction is carried out. At this time, the soluble Zn salt, soluble In salt and thioacetamide react to obtain ZnIn2S4, which is coated on MIL-88A to obtain a metal-organic framework composite material rich in sulfur vacancies.

[0010] Preferably, the mass ratio of MIL-88A to ZnIn2S4 is 1:1 or 1:3-6. If the proportion of MIL-88A is too high, the following defects will occur: a. Limited photocatalytic performance: The photocatalytic activity of MIL-88A itself is relatively low compared to ZnIn2S4. If its proportion is too high, in the photocatalytic reaction system, too much MIL-88A will cover up the photocatalytic active sites of ZnIn2S4. For example, in the photocatalytic decomposition of water to produce hydrogen, ZnIn2S4 is mainly able to absorb photons to generate electron-hole pairs. If the proportion of MIL-88A is too high, the generation of photogenerated carriers will be reduced, resulting in a decrease in the photocatalytic reaction rate and degradation efficiency. b. Poor cost-effectiveness: MIL-88A usually requires a period of time during the synthesis process. The raw material and process costs are determined by the amount of MIL-88A. If its usage is too high, the cost of the metal-organic framework composite material rich in sulfur vacancies will increase. Without a corresponding improvement in the catalytic performance, the cost-effectiveness of the metal-organic framework composite material rich in sulfur vacancies in practical applications will be reduced. c. Risk of pore blockage: MIL-88A is a porous material. When its proportion is too high, a large amount of MIL-88A accumulation may block its own pores and hinder the effective dispersion of pollutants in its pores. In this way, the entry of pollutants into MIL-88A and the diffusion of product molecules after the degradation of pollutants will be affected, which is not conducive to the catalytic reaction.

[0011] If the proportion of ZnIn2S4 is too high, there are the following defects: a. Reduced stability: Although ZnIn2S4 has good chemical stability, it may be more prone to agglomeration or structural damage in a complex reaction environment, such as a strong acidic or alkaline environment, without sufficient MIL-88A as support and protection. Specifically, in the process of photocatalytic degradation of organic pollutants, if the pH of the reaction system changes, a high proportion of ZnIn2S4 may affect its crystal structure, thereby reducing its photocatalytic performance and service life; b. Poor dispersibility: ZnIn2S4 requires a good carrier to achieve uniform dispersion. When the proportion of MIL-88A is too low, ZnIn2S4 is difficult to fully disperse on MIL-88A and is prone to agglomeration. The active sites of the agglomerated ZnIn2S4 cover each other, reducing the effective sites that can participate in the catalytic reaction and reducing the catalytic efficiency. It is like small ZnIn2S4 particles aggregate into large clumps, and pollutants are difficult to contact the active sites inside the clumps, affecting the catalytic reaction.

[0012] Preferably, the conditions for the hydrothermal reaction are: hydrothermal treatment at 403K to 433K for 10 to 12 hours; too high a temperature will cause the cracking of MIL-88A, while too low a temperature cannot ensure the integrity of the ZnIn2S4 crystal structure, and ZnIn2S4 may be formed; too short a hydrothermal time will result in insufficient reaction, while too long a hydrothermal time will result in the cracking and agglomeration of the metal-organic framework composite material rich in sulfur vacancies under long-term high temperature.

[0013] Preferably, the Zn in the soluble Zn salt is 2+ 、In in soluble In salts 3+ The molar ratio of S in thioacetamide is 1:2:4.

[0014] Preferably, MIL-88A is prepared according to the following steps:

[0015] The soluble iron source and fumaric acid were mixed in water and then hydrothermally reacted at 100°C for 12 h to obtain MIL-88A.

[0016] The invention also protects the metal organic framework composite material rich in sulfur vacancies prepared by the preparation method.

[0017] The present invention also protects a metal organic framework composite material rich in sulfur vacancies. In the metal organic framework composite material rich in sulfur vacancies, ZnIn2S4 is used as a shell and MIL-88A is used as a core. ZnIn2S4 and MIL-88A form a Z-type heterojunction and have a large number of sulfur vacancies.

[0018] The present invention also protects an ofloxacin photocatalytic degradation catalyst, which consists of the sulfur vacancy-rich metal organic framework composite material according to claim 6 and H2O2.

[0019] Preferably, the catalytic method for the photocatalytic degradation of ofloxacin is: ofloxacin, a metal organic framework composite material rich in sulfur vacancies and H2O2 are mixed together in water, and photocatalytic degradation is carried out under light conditions.

[0020] Preferably, the mass ratio of ofloxacin to the core-shell metal organic framework composite material is 2:5-30.

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

[0022] 1. The present invention uses MIL-88A, soluble Zn salt, soluble In salt and thioacetamide as raw materials, and prepares a metal organic framework composite material rich in sulfur vacancies through a hydrothermal reaction. In the metal organic framework composite material rich in sulfur vacancies obtained by the method of the present invention, MIL-88A is used as the core, ZnIn2S4 is used as the shell, ZnIn2S4 and MIL-88A form a Z-type heterojunction, and have a large number of sulfur vacancies. Compared with the traditional MIL-88A@ZnIn2S4 composite material, the present invention has the following advantages:

[0023] In terms of apparent quantum efficiency, the present invention broadens the light absorption range and enhances the light absorption intensity, and the Z-shaped heterojunction formed by the two enables the photogenerated carriers to be transferred to MIL-88A through the energy level difference, or an electric field that is conducive to carrier separation is formed between the two; the porous structure of MIL-88A provides a channel for the transmission of photogenerated carriers; MIL-88A is used as a carrier to disperse ZnIn2S4, reduce clusters, and increase active sites; the composite material has a large number of sulfur vacancies, which not only increases the active sites of the reaction, but also increases the electronic state density at the bottom of the conduction band, all of which can help improve the apparent quantum efficiency.

[0024] As for the recombination of photogenerated electron-hole pairs, the Z-type heterojunction of the present invention can effectively conduct photogenerated electrons, and the sulfur vacancies serve as capture centers for electrons or holes, inhibiting the recombination of photogenerated carriers and extending the lifespan, so that the metal organic framework composite material rich in sulfur vacancies has more opportunities to participate in the reaction, avoiding the rapid recombination of electron-hole pairs and increasing its photocatalytic performance.

[0025] The ionic bonds and covalent bonds formed between ZnIn2S4 and MIL-88A of the present invention provide good stability for the metal organic framework composite material rich in sulfur vacancies. The presence of sulfur vacancies changes the electronic structure and chemical environment of the catalyst surface, reduces the oxidation of sulfur atoms in the catalyst by photogenerated holes, thereby improving the stability of the catalyst and extending its service life. In addition, ZnIn2S4 has a relatively large specific surface area, and when it is composited on MIL-88A, the specific surface area of ​​MIL-88A is effectively increased, more active sites are provided, and agglomeration can be avoided.

[0026] As for the degradation of ofloxacin, sulfur vacancies are introduced through defect engineering to reduce the band gap of the metal-organic framework composite material rich in sulfur vacancies. At the same time, the surface properties and electronic structure of the metal-organic framework composite material rich in sulfur vacancies are changed to improve its Fenton-like reaction activity, thereby enhancing the degradation ability of the photo-Fenton system for ofloxacin.

[0027] 2. In the present invention, sulfur vacancies are mainly formed during the one-step hydrothermal preparation of MIL-88A@ZnIn2S4. The reasons for their formation are as follows: when the two materials are compounded, a redox reaction occurs, which may cause part of the S to be oxidized, and some sulfur atoms leave the original lattice position due to changes in their own valence state; under high temperature conditions, S atoms have a certain diffusion ability and are adsorbed to the surface by MIL-88A, resulting in S vacancies caused by their own escape; the hydrothermal time is extended without destroying the catalyst structure, and the chemical reaction in the system continues, the S atoms obtain more energy, the chemical bonds are more easily broken and reorganized, and some sulfur atoms can overcome the constraints of the lattice energy and leave the original crystal structure position, thereby generating sulfur vacancies.

[0028] 3. The metal organic framework composite material rich in sulfur vacancies of the present invention has a wide applicable pH range, as follows: MIL-88A has a regular crystal structure, and the iron ions are fixed in the framework structure of MOFs. They will not easily form precipitation like iron ions in a homogeneous system within a wider pH range. In addition, the surface properties of the metal organic framework composite material rich in sulfur vacancies can change the chemical environment of the iron ions, so that the iron ions remain active within a wider pH range; the photogenerated electrons generated by the photo-Fenton reaction can be transferred to the active sites of the metal organic framework composite material rich in sulfur vacancies to help activate hydrogen peroxide, and the photogenerated holes also participate in the oxidation reaction or promote the decomposition of hydrogen peroxide. This light-assisted process enhances the reaction activity of the heterogeneous photo-Fenton system within a wider pH range. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 In the figure, (a) is the SEM image of MIL-88A, (b) is the SEM image of ZnIn2S4, and (c) is the SEM image of ZM-0.05 of Example 1.

[0030] Figure 2 This is the EDS elemental analysis chart of Zn, In, Fe, O, C and S of ZM-0.05 of Example 1.

[0031] Figure 3 It is the high-resolution XPS spectrum of ZM-0.05 of Example 1, wherein (a) is the full XPS spectrum, (b) is the XPS spectrum of O1s, (c) is the XPS spectrum of Zn 2p, (d) is the XPS spectrum of In 3d, (e) is the XPS spectrum of S2p, and (f) is the XPS spectrum of Fe 2p.

[0032] Figure 4 The N2 adsorption-desorption isotherms of MIL-88A, ZnIn2S4 and ZM-0.05 of Example 1.

[0033] Figure 5 In the figure, (a) is a graph showing the photo-Fenton degradation performance of metal-organic framework composite materials rich in sulfur vacancies and ZnIn2S4 for ofloxacin in Examples 1 to 3 and Comparative Examples 1 to 2, and (b) is a graph showing the degradation rate curve fitted by (a).

[0034] Figure 6 This is the electron spin resonance spectrum of ZM-0.05 of Example 1.

[0035] Figure 7 In the figure, (a) is the UV-visible diffuse reflectance spectra of MIL-88A, ZnIn2S4 and ZM-0.05 of Example 1, (b) is the transient photocurrent response of MIL-88A, ZnIn2S4 and ZM-0.05 of Example 1, (c) is the photoluminescence intensity of MIL-88A, ZnIn2S4 and ZM-0.05 of Example 1, and (d) is the electrochemical impedance spectrum of MIL-88A, ZnIn2S4 and ZM-0.05 of Example 1.

[0036] Figure 8 In the figure, (a) is a graph showing the photo-Fenton degradation performance of ofloxacin at different dosages of ZM-0.05 of Example 1, (b) is a graph showing the degradation rate curve fitted by (a), (c) is a graph showing the photo-Fenton degradation performance of ofloxacin of ZM-0.05 of Example 1 at different hydrogen peroxide concentrations, and (d) is a graph showing the degradation rate curve fitted by (c).

[0037] Fig. 9 This is a graph showing the residual concentration of hydrogen peroxide during the degradation of ofloxacin using ZM-0.05 of Example 1.

[0038] Fig.10 In the figure, (a) is a photo-Fenton degradation performance diagram of ZM-0.05 ofloxacin in Example 1 under different pH conditions, and (b) is a degradation rate curve diagram fitted by (a).

[0039] Fig.11 In the figure, (a) is a photo-Fenton degradation performance diagram of ZM-0.05 of Example 1 for repeated use of ofloxacin, and (b) is an XRD diagram of ZM-0.05 of Example 1 before and after repeated use.

[0040] Fig.12 The schematic diagram of the degradation of ofloxacin by the metal organic framework composite material rich in sulfur vacancies of the present invention is shown. DETAILED DESCRIPTION

[0041] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] Taking into account the technical defect that the traditional MIL-88A@ZnIn2S4 composite material cannot achieve the degradation of ofloxacin, the present invention proposes a metal-organic framework composite material rich in sulfur vacancies. The metal-organic framework composite material rich in sulfur vacancies is a MIL-88A@ZnIn2S4 composite material rich in sulfur vacancies. Compared with the prior art MIL-88A@ZnIn2S4 composite material, under the preparation method of the present invention, due to the introduction of sulfur vacancies, the degradation of ofloxacin is achieved, thereby overcoming the technical defects of the prior art MIL-88A@ZnIn2S4 composite material.

[0043] The technical solution of the present invention is further explained by using embodiments and comparative examples, as shown below:

[0044] Example 1

[0045] A method for preparing a metal organic framework composite material rich in sulfur vacancies comprises the following steps:

[0046] S1. Preparation of MIL-88A: A one-step hydrothermal method was used to prepare the product. 10 mmol of FeCl3·6H2O and 10 mmol of fumaric acid were placed in a beaker filled with 50 mL of deionized water, stirred for 15 min, and then placed in a 150 mL Teflon-lined stainless steel autoclave, and heated in a 373K forced air drying oven for 12 h to react. After the reaction was completed, the product was naturally cooled to room temperature, and the orange-brown product was separated by centrifugation at a speed of 8000 r / min for 8 min. After being fully and alternately washed with deionized water and anhydrous ethanol, the product was vacuum dried at 333 K for 12 h to obtain the MIL-88A catalyst.

[0047] Among them, the mass of FeCl3·6H2O is 2.703g, and the mass of fumaric acid is 1.1607g.

[0048] S2. Preparation of metal-organic framework composite materials rich in sulfur vacancies: ZnIn2S4 nanosheets were grown on the surface of rod-shaped MIL-88A catalyst by a one-step hydrothermal method. 0.05 g of MIL-88A catalyst was dispersed in 30 mL of deionized water, and then 1.0 mmol of ZnCl2, 2.0 mmol of InCl3·4H2O and 4.0 mmol of thioacetamide were added and stirred for 30 min. After heating in a 433 K forced air drying oven for 12 h to react, the mixture was cooled to room temperature, washed alternately with deionized water and anhydrous ethanol, and then vacuum dried at 333 K for 12 h to obtain a yellow metal-organic framework composite material rich in sulfur vacancies. At this time, the mass ratio of MIL-88A to ZnIn2S4 nanosheets was 1:6, recorded as MIL-88A / ZnIn2S4-0.05 composite catalyst or ZM-0.05.

[0049] Example 2

[0050] The preparation method of the metal organic framework composite material rich in sulfur vacancies is the same as the preparation steps of Example 1, except that the mass of the MIL-88A catalyst is replaced from 0.05 g to 0.1 g, and comprises the following steps:

[0051] S1. Preparation of MIL-88A: A one-step hydrothermal method was used to prepare the product. 10 mmol of FeCl3·6H2O and 10 mmol of fumaric acid were placed in a beaker filled with 50 mL of deionized water, stirred for 15 min, and then placed in a 150 mL Teflon-lined stainless steel autoclave, and heated in a 373K forced air drying oven for 12 h to react. After the reaction was completed, the product was naturally cooled to room temperature, and the orange-brown product was separated by centrifugation at a speed of 8000 r / min for 8 min. After being fully and alternately washed with deionized water and anhydrous ethanol, the product was vacuum dried at 333 K for 12 h to obtain the MIL-88A catalyst.

[0052] Among them, the mass of FeCl3·6H2O is 2.703g, and the mass of fumaric acid is 1.1607g.

[0053] S2. Preparation of metal-organic framework composite materials rich in sulfur vacancies: ZnIn2S4 nanosheets were grown on the surface of rod-shaped MIL-88A catalyst by a one-step hydrothermal method. 0.1 g of MIL-88A catalyst was dispersed in 30 mL of deionized water, and then 1.0 mmol of ZnCl2, 2.0 mmol of InCl3·4H2O and 4.0 mmol of thioacetamide were added and stirred for 30 min. After heating in a 433 K forced air drying oven for 12 h to react, the mixture was cooled to room temperature, washed alternately with deionized water and anhydrous ethanol, and then vacuum dried at 333 K for 12 h to obtain a yellow metal-organic framework composite material rich in sulfur vacancies. At this time, the mass ratio of MIL-88A to ZnIn2S4 nanosheets was 1:3, recorded as MIL-88A / ZnIn2S4-0.1 composite catalyst or ZM-0.1.

[0054] Example 3

[0055] The preparation method of the metal organic framework composite material rich in sulfur vacancies is the same as the preparation steps of Example 1, except that the mass of the MIL-88A catalyst is replaced from 0.05 g to 0.3 g, and comprises the following steps:

[0056] S1. Preparation of MIL-88A: A one-step hydrothermal method was used to prepare the product. 10 mmol of FeCl3·6H2O and 10 mmol of fumaric acid were placed in a beaker filled with 50 mL of deionized water, stirred for 15 min, and then placed in a 150 mL Teflon-lined stainless steel autoclave, and heated in a 373K forced air drying oven for 12 h to react. After the reaction was completed, the product was naturally cooled to room temperature, and the orange-brown product was separated by centrifugation at a speed of 8000 r / min for 8 min. After being fully and alternately washed with deionized water and anhydrous ethanol, the product was vacuum dried at 333 K for 12 h to obtain the MIL-88A catalyst.

[0057] Among them, the mass of FeCl3·6H2O is 2.703g, and the mass of fumaric acid is 1.1607g.

[0058] S2. Preparation of metal-organic framework composite materials rich in sulfur vacancies: ZnIn2S4 nanosheets were grown on the surface of rod-shaped MIL-88A catalyst by a one-step hydrothermal method. 0.3 g of MIL-88A catalyst was dispersed in 30 mL of deionized water, and then 1.0 mmol of ZnCl2, 2.0 mmol of InCl3·4H2O and 4.0 mmol of thioacetamide were added and stirred for 30 min. After heating in a 433 K forced air drying oven for 12 h to react, the mixture was cooled to room temperature, washed alternately with deionized water and anhydrous ethanol, and then vacuum dried at 333 K for 12 h to obtain a yellow metal-organic framework composite material rich in sulfur vacancies. At this time, the mass ratio of MIL-88A to ZnIn2S4 nanosheets was 1:1, recorded as MIL-88A / ZnIn2S4-0.3 composite catalyst or ZM-0.3.

[0059] Example 4

[0060] A method for preparing a metal organic framework composite material rich in sulfur vacancies comprises the following steps:

[0061] S1. Preparation of MIL-88A: A one-step hydrothermal method was used to prepare the product. 10 mmol of FeCl3·6H2O and 10 mmol of fumaric acid were placed in a beaker filled with 50 mL of deionized water, stirred for 15 min, and then placed in a 150 mL Teflon-lined stainless steel autoclave, and heated in a 353K forced air drying oven for 11 h to react. After the reaction was completed, the product was naturally cooled to room temperature, and the orange-brown product was separated by centrifugation at a speed of 8000 r / min for 8 min. After being fully and alternately washed with deionized water and anhydrous ethanol, the product was vacuum dried at 333 K for 12 h to obtain the MIL-88A catalyst.

[0062] Among them, the mass of FeCl3·6H2O is 2.703g, and the mass of fumaric acid is 1.1607g.

[0063] S2. Preparation of metal-organic framework composite materials rich in sulfur vacancies: ZnIn2S4 nanosheets were grown on the surface of rod-shaped MIL-88A catalyst by a one-step hydrothermal method. 0.05 g of MIL-88A catalyst was dispersed in 30 mL of deionized water, and then 1.0 mmol of ZnCl2, 2.0 mmol of InCl3·4H2O and 4.0 mmol of thioacetamide were added and stirred for 30 min. After heating in a 403 K forced air drying oven for 11 h to react, the mixture was cooled to room temperature, washed alternately with deionized water and anhydrous ethanol, and then vacuum dried at 333 K for 12 h to obtain a yellow metal-organic framework composite material rich in sulfur vacancies.

[0064] Example 5

[0065] A method for preparing a metal organic framework composite material rich in sulfur vacancies comprises the following steps:

[0066] S1. Preparation of MIL-88A: Prepared by a one-step hydrothermal method, 10 mmol of FeCl3·6H2O and 10 mmol of fumaric acid were placed in a beaker filled with 50 mL of deionized water, stirred for 15 min, placed in a 150 mL Teflon-lined stainless steel autoclave, and heated in a 363K forced air drying oven for 10 h to react; after the reaction was completed, it was naturally cooled to room temperature, and the orange-brown product was centrifuged at a speed of 8000 r / min for 8 min. After being fully and alternately washed with deionized water and anhydrous ethanol, it was vacuum dried at 333 K for 12 h to obtain the MIL-88A catalyst;

[0067] Among them, the mass of FeCl3·6H2O is 2.703g, and the mass of fumaric acid is 1.1607g.

[0068] S2. Preparation of metal-organic framework composite materials rich in sulfur vacancies: ZnIn2S4 nanosheets were grown on the surface of rod-shaped MIL-88A catalyst by a one-step hydrothermal method. 0.05 g of MIL-88A catalyst was dispersed in 30 mL of deionized water, and then 1.0 mmol of ZnCl2, 2.0 mmol of InCl3·4H2O and 4.0 mmol of thioacetamide were added and stirred for 30 min. After heating in a 423 K forced air drying oven for 10 h to react, the mixture was cooled to room temperature, washed alternately with deionized water and anhydrous ethanol, and then vacuum dried at 333 K for 12 h to obtain a yellow metal-organic framework composite material rich in sulfur vacancies.

[0069] Comparative Example 1

[0070] The preparation method of the metal organic framework composite material rich in sulfur vacancies is the same as the preparation steps of Example 1, except that the mass of the MIL-88A catalyst is replaced from 0.05 g to 0.02 g, and comprises the following steps:

[0071] S1. Preparation of MIL-88A: A one-step hydrothermal method was used to prepare the product. 10 mmol of FeCl3·6H2O and 10 mmol of fumaric acid were placed in a beaker filled with 50 mL of deionized water, stirred for 15 min, and then placed in a 150 mL Teflon-lined stainless steel autoclave, and heated in a 373K forced air drying oven for 12 h to react. After the reaction was completed, the product was naturally cooled to room temperature, and the orange-brown product was separated by centrifugation at a speed of 8000 r / min for 8 min. After being fully and alternately washed with deionized water and anhydrous ethanol, the product was vacuum dried at 333 K for 12 h to obtain the MIL-88A catalyst.

[0072] Among them, the mass of FeCl3·6H2O is 2.703g, and the mass of fumaric acid is 1.1607g.

[0073] S2. Preparation of metal-organic framework composite materials rich in sulfur vacancies: ZnIn2S4 nanosheets were grown on the surface of rod-shaped MIL-88A catalyst by a one-step hydrothermal method. 0.02 g of MIL-88A catalyst was dispersed in 30 mL of deionized water, and then 1.0 mmol of ZnCl2, 2.0 mmol of InCl3·4H2O and 4.0 mmol of thioacetamide were added and stirred for 30 min. After heating in a 463 K forced air drying oven for 12 h to react, the mixture was cooled to room temperature, washed alternately with deionized water and anhydrous ethanol, and then vacuum dried at 333 K for 12 h to obtain a yellow metal-organic framework composite material rich in sulfur vacancies. At this time, the mass ratio of MIL-88A to ZnIn2S4 nanosheets was 1:15, recorded as MIL-88A / ZnIn2S4-0.02 composite catalyst or ZM-0.02.

[0074] Comparative Example 2

[0075] The preparation method of the metal organic framework composite material rich in sulfur vacancies is the same as the preparation steps of Example 1, except that the mass of the MIL-88A catalyst is replaced from 0.05 g to 0.2 g, and comprises the following steps:

[0076] S1. Preparation of MIL-88A: A one-step hydrothermal method was used to prepare the product. 10 mmol of FeCl3·6H2O and 10 mmol of fumaric acid were placed in a beaker filled with 50 mL of deionized water, stirred for 15 min, and then placed in a 150 mL Teflon-lined stainless steel autoclave, and heated in a 373K forced air drying oven for 12 h to react. After the reaction was completed, the product was naturally cooled to room temperature, and the orange-brown product was separated by centrifugation at a speed of 8000 r / min for 8 min. After being fully and alternately washed with deionized water and anhydrous ethanol, the product was vacuum dried at 333 K for 12 h to obtain the MIL-88A catalyst.

[0077] Among them, the mass of FeCl3·6H2O is 2.703g, and the mass of fumaric acid is 1.1607g.

[0078] S2. Preparation of metal-organic framework composite materials rich in sulfur vacancies: ZnIn2S4 nanosheets were grown on the surface of rod-shaped MIL-88A catalyst by a one-step hydrothermal method. 0.2 g of MIL-88A catalyst was dispersed in 30 mL of deionized water, and then 1.0 mmol of ZnCl2, 2.0 mmol of InCl3·4H2O and 4.0 mmol of thioacetamide were added and stirred for 30 min. After heating in a 463 K forced air drying oven for 12 h to react, the mixture was cooled to room temperature, washed alternately with deionized water and anhydrous ethanol, and then vacuum dried at 333 K for 12 h to obtain a yellow metal-organic framework composite material rich in sulfur vacancies. At this time, the mass ratio of MIL-88A to ZnIn2S4 nanosheets was 2:3, recorded as MIL-88A / ZnIn2S4-0.2 composite catalyst or ZM-0.2.

[0079] The MIL-88A / ZnIn2S4 composite catalysts with strong photocatalytic activity, high degradation efficiency and high reuse rate are prepared in Examples 1 to 5 of the present invention. The MIL-88A / ZnIn2S4 composite catalysts of Examples 1 to 3 are used as examples for research, and compared with Comparative Examples 1 to 2. The ZIS in the figure is ZnIn2S4. The specific research methods and results are as follows:

[0080] SEM images are shown in Figure 1 As shown, the morphological characteristics of MIL-88A, ZnIn2S4 and ZM-0.05 are shown. Figure 1 Figure (a) shows that MIL-88A has a spindle-like morphology with a diameter of 200nm and a length of 1.5μm to 2.5μm. The size distribution of MIL-88A is relatively uniform. Figure (b) in Figure 1 is the morphology of ZnIn2S4. Compared with ZnIn2S4, ZM-0.05 presents a typical layered structure. ZnIn2S4 is in situ grown on MIL-88A. The in situ growth not only maintains the morphology of ZnIn2S4 nanosheets, but also helps to form an intimate surface between ZnIn2S4 and MIL-88A.

[0081] Figure 2 The EDS results showed that Zn, In, Fe, O, C and S were uniformly distributed on the sulfur vacancy-rich metal-organic framework composites, further confirming the successful synthesis of the sulfur vacancy-rich metal-organic framework composites.

[0082] Figure 3 The results in Figure (a) show that ZnIn2S4 and MIL-88A are successfully composited; Figure 3 The results in Figure (c) show that the high-resolution Zn 2p spectrum of ZM-0.05 is divided into two peaks, located at 1022.2eV and 1045.2eV, representing Zn2+ Zn2p 3 / 2 State and Zn 2+ Zn 2p 1 / 2 state; Figure 3 Figure (b) shows the XPS spectrum of O1s, which is divided into three independent peaks centered at 529.1eV, 532.2eV, and 534.0eV, which are respectively attributed to the HOH, Fe-O, and carboxylic acid groups of C4H4O4 of MIL-88A; Figure 3 Figure (d) is the XPS spectrum of In 3d. 5 / 2 and In 3d 3 / 2 A pair of symmetrical peaks appeared at 445.2 eV and 452.8 eV, respectively, which are attributed to In 3+ The presence of S2p; the XPS spectrum of S2p is as follows Figure 3 As shown in Figure (e), the S2p centered at 161.9 eV and 163.2 eV 3 / 2 Peak and S2p 1 / 2 The peak is attributed to S in ZM-0.05 2- , Figure 3 Figure (f) is the XPS spectrum of Fe 2p, showing that 711.5eV, 713.4eV, 715.7eV and 718.9eV are all attributed to Fe 2p 3 / 2 The peaks of 722.0eV, 725.5eV and 729.5eV are all attributed to Fe 2p 1 / 2 The XPS spectrum results further confirmed the successful synthesis of sulfur vacancy-rich metal-organic framework composites.

[0083] The specific surface area and porosity of ZnIn2S4, MIL-88A and ZM-0.05 were studied by N2 adsorption-desorption experiments. Figure 4 The results show that the isotherms of ZnIn2S4 and ZM-0.05 are consistent with the type IV isotherms, and the type IV isotherms of the H3 hysteresis loop are in a relatively high relative pressure range, P / P0 = 0.45-1.0, indicating that ZnIn2S4 and ZM-0.05 are both mesoporous materials. At the same time, the isotherms of MIL-88A also belong to the type IV with H3 rings, P / P0 = 0.80-1.0. The specific surface areas of ZM-0.05, MIL-88A and ZnIn2S4 are 78.8060m 2 / g, 29.6517m 2 / g and 63.1244m 2 / g. These results prove that the embedded heterostructure formed by in situ growth of ZnIn2S4 effectively increases the surface area of ​​MIL-88A and provides more active sites. ZM-0.05 has the largest pore volume, which may be related to its porous structure, which promotes the subsequent photo-Fenton degradation experiments.

[0084] Figure 5 The adsorption and photo-Fenton degradation performance of ofloxacin on sulfur vacancy-rich metal-organic framework composites with different MIL-88A doping amounts were investigated. Figure 5 As shown in Figure (a), compared with ZnIn2S4, the photocatalytic ability of ZM-0.05 is significantly improved, and the adsorption stage is also slightly improved. ZM-0.05 has the best degradation effect on ofloxacin, reaching 91.6% within 90 minutes. The fitted degradation rate curve is shown in Figure 5 As shown in Figure (b).

[0085] Figure 6 This is the spectrum of electron spin resonance (ESR). ESR is a very effective method for proving the presence of sulfur vacancies in metal sulfides. In order to further confirm the generation of sulfur vacancies in the composite material, we conducted an ESR test to confirm the presence of sulfur vacancies in the material. It can be seen from the figure that ZM-0.05 exhibits an obvious electron spin resonance signal, while the resonance signal of the pure ZnIn2S4 sample is weak. This shows that there are a large number of sulfur vacancies on the surface of the ZM-0.05 composite material. The presence of sulfur vacancies increases the electron absorption capacity and reduces the electron cloud density, thereby improving the photocatalytic performance.

[0086] Figure 7 Figure (a) is a UV-Vis DRS spectrum, which determines the light absorption performance and intrinsic photocatalytic mechanism of MIL-88A, ZnIn2S4, and ZM-0.05. MIL-88A has a wide absorption band of 200nm to 710nm. The growth of ZnIn2S4 on the surface of MIL-88A has a positive effect on the visible light absorption of MIL-88A, resulting in a red shift in ZM-0.05 compared with MIL-88A and ZnIn2S4. Compared with ZnIn2S4, the heterojunction of ZM-0.05 exhibits strong light absorption, and ZM-0.05 maintains a wider light absorption range. This is due to the close contact between MIL-88A and ZnIn2S4 to form a core-shell structure and the introduction of sulfur vacancies, thereby enhancing the light response ability.

[0087] Figure 7Figure (b) is a transient photocurrent measurement diagram. The measurement method is: on an electrochemical workstation, Ag / AgCl electrode is used as the reference electrode, Pt sheet is used as the counter electrode, and ITO glass loaded with ZM-0.05 is used as the working electrode. Photoelectrochemical analysis is performed in a three-electrode system. The light source is a 300W xenon lamp, and the electrolyte is a 0.5mol / L Na2SO4 solution. The transient photocurrent response reflects the interface electron-hole separation efficiency and light response ability. Generally speaking, the faster the separation speed of photogenerated carriers, the higher the photocurrent intensity. ZM-0.05 has the highest photocurrent intensity, corresponding to its superior photocatalytic performance. The order of current intensity is Figure 5 The experimental results in Figure (b) are basically consistent, so the combination of MIL-88A and ZnIn2S4 can greatly prolong the effective reaction time of the photoinduced carrier.

[0088] like Figure 7 As shown in Figure (c), the photoluminescence intensities of ZnIn2S4 and MIL-88A are both higher than those of ZM-0.05, mainly due to the close interface within the heterojunction, which further verifies that the metal-organic framework composite material rich in sulfur vacancies can effectively promote the separation of photogenerated carriers. Therefore, the above electrochemical characterization provides a reasonable explanation for the photocatalytic experimental phenomenon.

[0089] EIS spectra of MIL-88A, ZnIn2S4 and ZM-0.05 are shown in Figure 7 As shown in Figure (d), the smaller the arc radius, the lower the charge transfer resistance. Compared with ZnIn2S4, the arc radius of ZM-0.05 is smaller, indicating that the heterojunction helps to reduce the charge transfer resistance and promote carrier separation. In addition, from another perspective, it is confirmed that the construction of the heterojunction and the introduction of sulfur vacancies suppress the photoelectron-hole recombination, because the higher the fluorescence intensity, the faster the recombination rate.

[0090] Figure 8 Figure (a) shows the degradation reaction curves at different ZM-0.05 dosages. Figure 8Figure (b) is a bar graph of the reaction rate constants at different ZM-0.05 dosages. The degradation reaction method is: 0.09g, 0.06g, 0.045g, 0.03g, and 0.015g of ZM-0.05 were added to 300mL ofloxacin solution at pH 7.0, respectively, and reacted in the dark for 30 minutes to eliminate the influence of the adsorption effect on the catalytic reaction. At the same time, the condensation water system switch of the photoreactor was turned on, and a 500W xenon lamp was turned on for preheating; after the dark reaction, the reaction tube was placed under the light source, and then 0.3mL of H2O2 was added for a visible light photo-Fenton experiment. The reaction time was 90 minutes. 2mL of the supernatant was taken every 15 minutes, and 0.2mL of tert-butanol was added to the supernatant to terminate the reaction. After centrifugation and filtration with a needle filter with a pore size of 2μm, the absorbance value at a wavelength of 293nm was determined by spectrophotometry.

[0091] When the dosage of ZM-0.05 was 0.05 g / L and 0.3 g / L, respectively, the adsorption ratio of ofloxacin in the dark reaction stage increased from 22.2% to 71.5%, and the removal rate of ofloxacin increased from 57.1% to 87.7% within 30 min. The results showed that the increase in the dosage of ZM-0.05 provided more adsorption and catalytic active sites for adsorption and photo-Fenton reaction, and produced more hydroxyl radicals while improving the adsorption efficiency, which also confirmed the results of the above N2 adsorption-desorption experiment. In addition, when the dosage of ZM-0.05 was between 0.1 g / L and 0.3 g / L, the degradation effect and degradation rate of ofloxacin decreased. This is because a large amount of ofloxacin was adsorbed on the surface of ZM-0.05, and the aggregation of ZM-0.05 reduced the number of available active sites. In addition, the aggregation of ZM-0.05 increased the scattering of light, resulting in a slower reaction rate.

[0092] Figure 8 Figure (c) shows the degradation reaction curves under different H2O2 concentrations. Figure 8 Figure (d) is a bar graph of reaction rate constants under different H2O2 concentrations. The method of the degradation reaction is: add 0.045g of ZM-0.05 to 300mL ofloxacin solution with a pH of 7, and react in the dark for 30min to eliminate the influence of the adsorption effect on the catalytic reaction. At the same time, turn on the switch of the photoreactor condensate system and turn on the 500W xenon lamp for preheating; after the dark reaction, place the reaction tube under the light source, add 0.15mL, 0.3mL, 0.45mL, and 0.6mL of H2O2 respectively for visible light photo-Fenton experiment, and the reaction time is 90min. Take 2mL of the supernatant every 15min, add 0.2mL of tert-butanol to the supernatant to terminate the reaction, centrifuge, filter with a needle filter with a pore size of 2μm, and then detect. The absorbance value at a wavelength of 293nm is determined by spectrophotometry.

[0093] Fig. 9 is the residual concentration of hydrogen peroxide during the degradation of ofloxacin in a Fenton-like system. After 30 min, 60 min and 90 min, the concentrations of hydrogen peroxide in the solution were 7.25 mmol / L, 3.13 mmol / L and 1.37 mmol / L, respectively, indicating that the utilization rate of hydrogen peroxide in ZM-0.05 was high (50.3% at 30 min, 82.5% at 60 min and 91.8% at 90 min). The determination method is as follows: add 0.045g of ZM-0.05 to 300mL ofloxacin solution with a pH of 7, react in the dark for 30min to eliminate the influence of the adsorption effect on the catalytic reaction, turn on the condensation water system switch of the photoreactor at the same time, and turn on the 500W xenon lamp for preheating; after the dark reaction is completed, place the reaction tube under the light source, add 0.3mL of H2O2, take 1mL of the upper clear liquid at 0min, 30min, 60min, and 90min respectively, add 1mL of potassium iodide (0.4M KI) and 1mL of potassium hydrogen phthalate (0.1MC8H5KO4), and determine the absorbance at 350nm by ultraviolet spectrophotometry (UV-3600PLUS, SHIMADZU).

[0094] As the concentration of hydrogen peroxide increased from 4.90mmol / L to 9.79mmol / L, the removal rate of ofloxacin increased from 84.9% to 93.4%, and the fitted reaction rate constant k value also increased from 0.01313min -1 Increased to 0.02039min -1 , increased by 1.55 times; this is because higher concentrations of hydrogen peroxide can capture photoinduced electrons, inhibit the rapid recombination of electrons and holes, and produce more hydroxyl radicals. When the concentration of hydrogen peroxide increased to 19.58mmol / L, the degradation efficiency of ofloxacin decreased slightly from 93.4% to 86.3%, and the corresponding reaction rate constant k value also decreased from 0.02039min -1 Down to 0.0134min -1 ; This may be due to the self-quenching of free radicals at higher concentrations of hydrogen peroxide. The degradation efficiency did not increase further and the degradation rate slowed down, probably because the hydroxyl radicals were consumed by the remaining hydrogen peroxide, forming less active species. Overall, the addition of hydrogen peroxide significantly improved the degradation efficiency compared with photocatalytic degradation alone.

[0095] Fig.10 Figure (a) shows the reaction curve of ZM-0.05 degrading ofloxacin under different pH conditions. Fig.10Figure (b) is a bar graph of the reaction rate constants of ofloxacin degradation by ZM-0.05 under different pH conditions. The degradation reaction method is: add 0.045g of ZM-0.05 to 300mL ofloxacin solutions with pH values ​​of 3, 5, 7, 9, and 11, respectively, and react in the dark for 30min to eliminate the influence of the adsorption effect on the catalytic reaction. At the same time, turn on the switch of the photoreactor condensate water system and turn on a 500W xenon lamp for preheating. After the dark reaction, place the reaction tube under a light source, add 0.3mL of H2O2 to perform a visible light photo-Fenton experiment, and the reaction time is 90min. Take 2mL of the supernatant every 15min, add 0.2mL of tert-butanol to the supernatant to terminate the reaction, centrifuge, and filter with a needle filter with a pore size of 2μm for detection. The absorbance value at a wavelength of 293nm is determined by spectrophotometry.

[0096] The results showed that with the increase of pH value, the negative charge on the surface of ZM-0.05 increased, resulting in an increase in electrostatic repulsion and a decrease in adsorption performance. When the pH value was between 3 and 7, the degradation effect was basically maintained at a high level, because the acidic conditions were conducive to the formation of hydroxyl radicals, which attacked ofloxacin, produced more iron ions, and accelerated the leaching reaction. When the pH increased to 11.0, the degradation efficiency of ofloxacin was only 74.2% after 90 minutes, and the catalytic efficiency was significantly reduced. Although high alkalinity would partially destroy the photo-Fenton system, 87.9% of ofloxacin could still be degraded within 90.0 minutes under pH = 9.

[0097] Fig.11 Figure (a) shows the degradation curve of ZM-0.05 after four reuses. The reuse method is as follows: 0.045g of ZM-0.05 was added to 300mL ofloxacin solution at pH 7, and reacted in the dark for 30min to eliminate the influence of adsorption on the catalytic reaction. At the same time, the switch of the photoreactor condensation water system was turned on, and a 500W xenon lamp was turned on for preheating. After the dark reaction, the reaction tube was placed under the light source, and 0.3mL of H2O2 was added for visible light photo-Fenton experiment. The reaction time was 90min. Every 15min, 2mL of the supernatant was taken, and 0.2mL of tert-butyl alcohol was added to the supernatant to terminate the reaction. After centrifugation and filtration with a needle filter with a pore size of 2μm, the absorbance value at a wavelength of 293nm was determined by spectrophotometry. In this study, ZM-0.05 was collected by centrifugation, then washed with dilute nitric acid, and reused in the next round of reaction.

[0098] The removal efficiency of ofloxacin decreased from 93.4% to 84.9%, which was 8.5% lower than the initial degradation efficiency. This may be due to the fact that Fe 3+In order to further determine the structural changes of sulfur vacancy-rich metal-organic framework composites during recycling, Fig.11 Figure (b) compares the XRD spectra of ZM-0.05 before and after the reaction. The position and intensity of the characteristic peaks indicate that its basic structure remains unchanged. So overall, the heterojunction can maintain a stable structure and has great potential for practical applications.

[0099] The principle of using the metal organic framework composite material rich in sulfur vacancies to degrade ofloxacin is: + (electron hole), O2 ·- , 1 O2 and ·OH free radicals attack ofloxacin, converting it into small molecular intermediates and finally into CO2 and H2O. Fig.12 As shown, according to the different reaction sites on ofloxacin, there are five pathways for degradation. First, ·OH attacks the CN bond on the piperazine ring to generate P1, and then continues to break the CN bond on the left to generate P2; in pathway 2, ofloxacin is demethylated to generate compound P3, which is susceptible to electrophilic attack by the free radical ·OH to generate the hydroxylated product compound P4. In addition, P5 is demethylated to generate P13. In pathway 3, the C atom of ofloxacin connected to the carboxyl group is attacked by the ·OH radical, decarboxylated to generate P6, and then decarbonylated to generate P7. The generated P7 is defluorinated, dihydroxylated, and demethylated to generate P8 and P9, respectively. In pathway 4, the C atom of ofloxacin connected to the carboxyl group is attacked by ·OH, and a cleavage reaction occurs on the porphyrin ring of the ofloxacin drug to generate P10. The C at the top of the quinolone ring is attacked by h + Under the attack of ·OH free radical, the important intermediate P10 of ofloxacin is further degraded to P11. C6 further loses the benzene ring under the attack of ·OH free radical to obtain intermediate P12. Under the continuous action of ·OH, P12 loses C4H 10 FN generates P13, and compound P13 is degraded to form organic acids and mineralization products. In pathway 5, ofloxacin is dehydrogenated to form C=C P14. Piperazine ring demethylation and quinolone partial decarboxylation generate P15. P16 and P17 are ultimately due to h + The action of and ·OH causes the piperazine ring to break. Finally, under the action of active substances, most of the above intermediates are further mineralized into CO2 and H2O. Therefore, according to the five main degradation pathways listed above, ·OH participates in the degradation of ofloxacin as the main active free radical. Compared with the reaction involving electron-hole pairs in a single photocatalysis, the photo-Fenton reaction with H2O2 as the oxidant can provide enough ·OH, and due to the presence of sulfur vacancies in the catalyst, H2O2 is rapidly activated to produce ·OH.

[0100] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations. The above-mentioned embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope thereof is not limited thereto.

Claims

1. A method for preparing a metal organic framework composite material rich in sulfur vacancies, characterized in that: The following steps are involved: MIL-88A is dispersed in deionized water, and then soluble Zn salt, soluble In salt and thioacetamide are added thereto. After mixing evenly, a hydrothermal reaction is carried out. At this time, the soluble Zn salt, soluble In salt and thioacetamide react to obtain ZnIn2S4, which is coated on MIL-88A to obtain a metal-organic framework composite material rich in sulfur vacancies.

2. The method for preparing a metal organic framework composite material rich in sulfur vacancies according to claim 1, characterized in that: The conditions of the hydrothermal reaction are: hydrothermal reaction at 403K~433K for 10h~12h.

3. The method for preparing the metal organic framework composite material rich in sulfur vacancies according to claim 1, characterized in that: The mass ratio of MIL-88A to ZnIn2S4 is 1:1 or 1:3-6.

4. The method for preparing a metal organic framework composite material rich in sulfur vacancies according to claim 1, characterized in that: Zn in soluble Zn salts 2+ 、In in soluble In salts 3+ The molar ratio of S in thioacetamide is 1:2:

4.

5. The method for preparing a metal organic framework composite material rich in sulfur vacancies according to claim 1, characterized in that: MIL-88A was prepared as follows: The soluble iron source and fumaric acid are mixed in water, and then hydrothermally reacted at 80° C. to 100° C. for 10 to 12 hours to obtain MIL-88A.

6. A metal organic framework composite material rich in sulfur vacancies obtained by the preparation method according to any one of claims 1 to 5, characterized in that: In the metal-organic framework composite material rich in sulfur vacancies, ZnIn2S4 is used as the shell and MIL-88A is used as the core. ZnIn2S4 and MIL-88A form a Z-type heterojunction and have a large number of sulfur vacancies.

7. An ofloxacin photocatalytic degradation catalyst, characterized in that: The ofloxacin photocatalytic degradation catalyst consists of the metal organic framework composite material rich in sulfur vacancies as claimed in claim 6 and H2O2.

8. The ofloxacin photocatalytic degradation catalyst according to claim 7, characterized in that: The catalytic method of the ofloxacin photocatalytic degradation catalyst is: Ofloxacin, a metal-organic framework composite material rich in sulfur vacancies and H2O2 were mixed together in water and photocatalytically degraded under light conditions.

9. The ofloxacin photocatalytic degradation catalyst according to claim 8, characterized in that: The mass ratio of ofloxacin to the metal organic framework composite material rich in sulfur vacancies is 2:5-30.

Images