Organic-metal skeleton / FeS composite photocatalytic material and preparation method and application thereof

Abstract

The application discloses an organic-metal skeleton / FeS composite photocatalytic material and a preparation method and application thereof, and the preparation method comprises the following steps: dissolving soluble zirconium salt and 2,5-dimercaptoterephthalic acid into a mixed solution of glacial acetic acid and N,N-dimethylformamide and uniformly mixing; performing first solvothermal reaction on the prepared solution to prepare UiO-66-SH2; adding UiO-66-SH2 and 1,8-diazabicyclo[5.4.0]undec-7-ene into an N,N-dimethylformamide solution of FeSO4 and stirring and reacting at room temperature; adding thiourea into the reacted solution to perform second solvothermal reaction, thereby obtaining the UiO-66-S-FeS-x photocatalytic material. The prepared photocatalytic material has good photocatalytic performance, and when applied to photocatalytic degradation of tetracycline in water, the degradation rate of tetracycline reaches more than 99% after irradiation for 120 min under visible light (300W xenon lamp, greater than or equal to 400nm).

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to an organic-metal framework / FeS composite photocatalytic material, its preparation method, and its application. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] With the continuous advancement of industrial development and the synthesis of new materials, new pollutants are entering water bodies through wastewater discharge, posing potential harm to aquatic ecosystems and human health. Photocatalysis, as a highly efficient, green, and low-carbon water treatment technology, is currently a hot research topic and a challenging area for degrading these new pollutants.

[0004] Currently, numerous photocatalytic materials, such as TiO2 and CdS, are being extensively studied. Their principle is based on the generation of electron-hole pairs under sunlight, which triggers redox reactions and degrades organic pollutants. Furthermore, the performance and degradation efficiency of photocatalytic materials can be further improved through modification and compositing. Despite significant progress in photocatalysis technology, many challenges and limitations remain in addressing the degradation of increasingly emerging pollutants. For example, the stability of photocatalytic materials, light utilization, and degradation mechanisms still require further research and improvement.

[0005] Ferrous sulfide (FeS) nanomaterials, as important transition metal chalcogenides, have broad application prospects in photocatalysis due to their good electrical conductivity, photocatalytic properties, stable chemical properties, and low biotoxicity. Among them, FeS nanomaterials have been extensively studied due to their high specific surface area and good absorption characteristics in the visible and infrared light bands resulting from their narrow band gap. However, single FeS nanomaterials still suffer from high photogenerated carrier-hole recombination rates and easy particle aggregation, leading to reduced catalytic efficiency and limiting their applications.

[0006] MOFs (Metal-Organic Facility Materials) are porous crystalline framework materials composed of organic linkers and coordinated metal clusters. They have been applied in many fields such as gas adsorption and separation, and catalysis. Due to their similar properties to inorganic semiconductors, they have broad application prospects in photocatalysis. The topological structure of MOFs determines that their active sites are relatively dispersed, not prone to aggregation, and have high stability. Their high specific surface area can generate abundant catalytic sites, and the interconnected channels within them are conducive to the transport of photogenerated carriers, thereby enhancing photocatalytic activity. However, when MOFs are used directly as photocatalysts, the metal sites are easily occupied by organic ligands, reducing their photocatalytic activity. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide an organic-metal framework / FeS composite photocatalytic material, its preparation method, and its application. This composite photocatalytic material can improve the utilization rate of visible light, promote the separation of photogenerated carriers and holes, and improve photocatalytic efficiency.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing an organic-metal framework / FeS composite photocatalytic material, comprising the following steps:

[0010] Dissolve soluble zirconium salt and 2,5-dimercaptoterephthalic acid in a mixture of glacial acetic acid and N,N-dimethylformamide, and mix well.

[0011] The solution prepared above was subjected to a first solvothermal reaction to prepare UiO-66-SH2;

[0012] UiO-66-SH2 and 1,8-diazabicyclo[5.4.0]undec-7-ene were added to an N,N-dimethylformamide solution of FeSO4, and the mixture was stirred at room temperature.

[0013] Thiourea was added to the solution after the reaction, and a second solvothermal reaction was carried out to prepare the UiO-66-S-FeS-x photocatalytic material.

[0014] Soluble zirconium salts are used to provide metal ions; 2,5-dimercaptoterephthalic acid serves as an organic ligand in the formation of MOFs; N,N-dimethylformamide is used as a linker; glacial acetic acid is used for etching to form a porous structure.

[0015] During the first solvothermal reaction, metal ions Zr 4+ UiO-66-SH2 crystals were prepared by coordinating with the organic ligand 2,5-dimercapto-terephthalic acid.

[0016] N,N-Dimethylformamide as a linker; 1,8-diazabicyclo[5.4.0]undec-7-ene neutralizes the thiol group and Fe 2+ The protons produced in the reaction break the SH bond and form an S-Fe bond. The role of thiourea is to provide a sulfur source.

[0017] In some embodiments, the soluble zirconium salt is ZrCl4, Zr(NO3)4, or Zr(SO4)2.

[0018] In some embodiments, the molar ratio of ZrCl4, organic ligand, glacial acetic acid, and N,N-dimethylformamide is 1:0.1-5:50-150:600-700.

[0019] In some embodiments, the temperature of the first solvothermal reaction is 100-150°C, and the reaction time is 30-50 h.

[0020] In some embodiments, the mass ratio of UiO-66-SH2, FeSO4, N,N-dimethylformamide, 1,8-diazabicyclo[5.4.0]undec-7-ene and thiourea is 1:0.1-2:900-1000:0.1-1:1-2.

[0021] In some embodiments, the stirring reaction is carried out at room temperature for 12-48 hours.

[0022] In some embodiments, the temperature of the second solvothermal reaction is 70-100°C, and the reaction time is 12-48 h.

[0023] Secondly, the present invention provides an organic-metal framework / FeS composite photocatalytic material, which is prepared by the aforementioned preparation method.

[0024] Thirdly, the present invention provides the application of the aforementioned organic-metal framework / FeS composite photocatalytic material in the photocatalytic degradation of tetracycline.

[0025] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0026] The photocatalytic material of this invention retains the original characteristics of MOFs, such as large specific surface area and dispersed active sites, by introducing FeS to redshift the light absorption range of the material and improve the visible light utilization rate of the material.

[0027] The photocatalytic material described in this invention accelerates the transport of photogenerated carriers by means of S-Fe bonds, further promoting the separation of photogenerated carriers and holes and improving photocatalytic efficiency.

[0028] The photocatalytic material described in this invention has excellent photocatalytic performance. When applied to the photocatalytic degradation of tetracycline in water, under visible light irradiation (300W xenon lamp, ≥400nm), the degradation rate of tetracycline reaches over 99% after 120 minutes of irradiation, demonstrating broad application prospects in the field of photocatalysis. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0030] Figure 1 The material used in Example 1 is UiO-66-S-FeS 0.5 SEM images;

[0031] Figure 2 The image shows the photocatalytic degradation effect of tetracycline on material UiO-66-(SH)2 and different doping amounts of UiO-66-S-FeSx (x=0.3,0.5,0.7,1) in Example 2.

[0032] Figure 3 The graph shows the photocatalytic degradation rate of tetracycline by material UiO-66-(SH)2 and different doping amounts of UiO-66-S-FeSx (x=0.3,0.5,0.7,1) in Example 2.

[0033] Figure 4 Example 3: Different doses of UiO-66-S-FeS 0.5 Photocatalytic degradation effect of tetracycline;

[0034] Figure 5 The material used in Example 4 is UiO-66-S-FeS. 0.5 Graph showing the effect of cyclic degradation of tetracycline. Detailed Implementation

[0035] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0036] The present invention will be further described below with reference to the embodiments.

[0037] Example 1

[0038] 0.027 g, 0.046 g, 0.064 g, and 0.092 g of FeSO4·7H2O (FeSO4 to UiO-66-(SH)2 mass ratios of 30 wt%, 50 wt%, 70 wt%, and 100 wt%, respectively) were dissolved in 50 mL of N,N-dimethylformamide (DMF). 50 mg of UiO-66-(SH)2 and 30 mg of 1,8-diazabicyclo[5.4.0]undec-7-ene were added, and the mixture was stirred for 24 h. 76 mg of thiourea was added to the above solution, and the mixture was stirred at 80 °C for 24 h. After cooling, the mixture was washed with DMF and anhydrous ethanol, separated, and dried to obtain the UiO-66-S-FeS photocatalytic material. The prepared photocatalytic material was named UiO-66-S-FeSx (x=0.3,0.5,0.7,1), where x=0.3~1 represents the mass ratio of FeSO4 added.

[0039] The preparation method of UiO-66-(SH)2 is as follows:

[0040] ZrCl4 (0.25 g) and (SH)2-BDC (0.247 g) in a 1:1 molar ratio were added to 66.7 mL of DMF and dissolved by sonication. Then, 8.3 mL of glacial acetic acid was added and the mixture was evenly dispersed. The resulting homogeneous solution was transferred to a polytetrafluoroethylene-lined autoclave and subjected to a solvothermal reaction for 48 h. After naturally cooling to room temperature, the material was washed, separated, and dried with DMF and anhydrous ethanol to obtain UiO-66-(SH)2.

[0041] Figure 1 The UiO-66-S-FeS obtained from the above steps 0.5 SEM image of the material.

[0042] Example 2

[0043] The photocatalytic degradation performance of UiO-66-(SH)2 and UiO-66-S-FeSx with different doping levels (x = 0.3, 0.5, 0.7, 1) on tetracycline under visible light was evaluated in Example 1. Visible light was provided using a 300W xenon lamp and a 400nm UV cutoff filter (>400nm).

[0044] 10 mg of UiO-66-(SH)2 and photocatalysts with different Fe doping amounts, UiO-66-S-FeSx (x = 0.3, 0.5, 0.7, 1), were dispersed in a photocatalytic double-layer reactor containing cooling water. 50 mL of 20 mg / L tetracycline solution was added, and the mixture was stirred and adsorbed in the dark for 30 min to reach adsorption-desorption equilibrium. After the dark reaction was completed, the xenon lamp was turned on, and about 1 mL of the suspension was taken at intervals. After filtration through a 0.22 μm filter membrane, the degradation rate of tetracycline was determined by high performance liquid chromatography.

[0045] Figure 2 The image shows the photocatalytic degradation effect of the photocatalytic material UiO-66-(SH)2 prepared in Example 1 of this invention and UiO-66-S-FeSx with different doping amounts (x = 0.3, 0.5, 0.7, 1) on tetracycline (20 mg / L) under visible light. Figure 2 It can be seen that FeS doping significantly improves the adsorption and degradation rates, and the photocatalytic effect is significantly enhanced when the doping concentration reaches 50% or higher. Figure 3 It can be seen that FeS doping significantly improves the degradation rate. The rate constants k of UiO-66-(SH)2 and UiO-66-S-FeSx (x=0.3,0.5,0.7,1) with different doping amounts are 0.00318, 0.01553, 0.0242, 0.02404 and 0.02371, respectively. Among them, UiO-S-FeS0.5 has the fastest degradation rate and the best photocatalytic effect.

[0046] Example 3

[0047] Evaluation of different doses of UiO-66-S-FeS 0.5 Photocatalytic degradation of tetracycline by photocatalytic materials under visible light. Visible light was provided using a 300W xenon lamp and a 400nm ultraviolet cutoff filter (>400nm).

[0048] Different doses (0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L) of UiO-66-S-FeS were respectively used. 0.5 The photocatalytic material was dispersed in a photocatalytic double-layer reactor containing cooling water, and 50 mL of 20 mg / L tetracycline solution was added. The mixture was stirred and adsorbed in the dark for 30 min to reach adsorption and desorption equilibrium. After the dark reaction was completed, the xenon lamp was turned on, and about 1 mL of the suspension was taken at intervals. After filtration through a 0.22 μm filter membrane, the degradation rate of tetracycline was determined by high performance liquid chromatography.

[0049] Figure 4 The photocatalyst UiO-66-S-FeS prepared in Example 1 of this invention at different dosages 0.5 Photocatalytic degradation effect of tetracycline (20 mg / L) under visible light. Figure 4 It can be seen that, with UiO-66-S-FeS 0.5 With increasing dosage, both adsorption rate and degradation rate increase, but UiO-66-S-FeS 0.5 When the dosage reaches 0.4 g / L, the photocatalytic degradation effect only shows a slight improvement. Therefore, the photocatalytic material UiO-66-S-FeS prepared in this invention... 0.5 The effect is best at a dose of 0.3 g / L.

[0050] Example 4

[0051] Evaluation of UiO-66-S-FeS 0.5 Stability of photocatalytic materials. Visible light was provided using a 300W xenon lamp and a 400nm ultraviolet cutoff filter (>400nm).

[0052] Using UiO-66-S-FeS 0.5 The photocatalytic material underwent five photocatalytic degradations of tetracycline. After each cycle, the collected photocatalytic material was washed and dried. Figure 5 As shown, after 5 cycles, the photocatalytic efficiency of tetracycline can still reach 79.7%, indicating that the photocatalytic material prepared in this invention has good recyclability.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an organic-metal framework / FeS composite photocatalytic material, characterized in that: Includes the following steps: Dissolve soluble zirconium salt and 2,5-dimercaptoterephthalic acid in a mixture of glacial acetic acid and N,N-dimethylformamide, and mix well. The solution prepared above was subjected to a first solvothermal reaction to prepare UiO-66-(SH)2; UiO-66-(SH)2 and 1,8-diazabicyclo[5.4.0]undec-7-ene were added to an N,N-dimethylformamide solution of FeSO4, and the mixture was stirred at room temperature. Thiourea was added to the solution after the reaction, and a second solvothermal reaction was carried out to prepare the UiO-66-S-FeS-x photocatalytic material.

2. The preparation method of the organo-metal framework / FeS composite photocatalytic material according to claim 1, characterized in that: The soluble zirconium salt is ZrCl4, Zr(NO3)4, or Zr(SO4)2.

3. The preparation method of the organo-metal framework / FeS composite photocatalytic material according to claim 2, characterized in that: The molar ratio of ZrCl4, 2,5-dimercaptoterephthalic acid, glacial acetic acid, and N,N-dimethylformamide is 1:0.1-5:50-150:600-700.

4. The preparation method of the organo-metal framework / FeS composite photocatalytic material according to claim 1, characterized in that: The temperature of the first solvothermal reaction is 100-150℃.

5. The method for preparing the organo-metal framework / FeS composite photocatalytic material according to claim 4, characterized in that: The first solvothermal reaction takes 30-50 hours.

6. The preparation method of the organo-metal framework / FeS composite photocatalytic material according to claim 1, characterized in that: The mass ratio of UiO-66-(SH)2, FeSO4, N,N-dimethylformamide, 1,8-diazabicyclo[5.4.0]undec-7-ene and thiourea is 1:0.1-2:900-1000:0.1-1:1-2.

7. The preparation method of the organo-metal framework / FeS composite photocatalytic material according to claim 1, characterized in that: The reaction time at room temperature is 12-48 hours.

8. The method for preparing the organo-metal framework / FeS composite photocatalytic material according to claim 1, characterized in that: The temperature of the second solvothermal reaction is 70-100℃, and the reaction time is 12-48h.

9. An organic-metal framework / FeS composite photocatalytic material, characterized in that: It is prepared by any one of the preparation methods described in claims 1-8.

10. The application of the organic-metal framework / FeS composite photocatalytic material according to claim 9 in the photocatalytic degradation of tetracycline.

Images