A core-shell structure Fe 0 Method for preparing a composite photo-fenton catalyst of UiO-66-NH2 and method of using the same

Abstract

The application discloses a kind of core-shell structure Fe 0 The application discloses a preparation method and use method of a core-shell structure Fe 0 @UiO-66-NH2 composite catalyst, the sample of step 2 is added to sodium borohydride (NaBH4) for reduction, and after acid washing, filtration and vacuum drying, the Fe 0 @UiO-66-NH2 composite catalyst is obtained.The purpose of the application is to provide a kind of core-shell structure Fe 0 @UiO-66-NH2 composite photocatalyst preparation method and use method thereof.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of photocatalyst preparation, in particular to a core-shell structure Fe 0 Preparation method of composite photo-Fenton catalyst of UiO-66-NH2 and use method thereof. BACKGROUND

[0002] Metal organic framework (MOFs) material is an ordered porous crystal composed of metal nodes and organic ligands, has the advantages of easy-to-adjust structure, high specific surface area and ordered pore structure. The structure of MOFs can be adjusted by changing the properties of metal atoms and connecting bodies or introducing metal ions, heteroatom rings and functional groups by modifying organic ligands, so that the MOFs exhibit excellent performance in the fields of chemical sensing, physical adsorption, functional catalysis and gas separation. According to the differences of metal center atoms and organic ligands, the MOFs are divided into the following types: MIL series, IRMOF series, ZIF series, UiO series and PCN series.

[0003] At present, the exploration of MOFs as a new type of photocatalyst has made certain progress, and is mainly used for pollutant degradation, hydrogen production by hydrolysis, heavy metal reduction, CO2 reduction and organic conversion. However, most of the MOFs are difficult to be applied in industry due to poor hydrothermal stability. n-type Zr-based MOFs, namely the UiO-66 series, are few MOFs materials with excellent thermochemical stability and water stability. In addition, the UiO-66 also exhibits excellent mechanical, acidic and water vapor stability. The UiO-66-NH2 which introduces amino groups is also a photocatalyst with visible light response. The organic connecting agent can generate separation of electrons and holes under visible light excitation, and the high specific surface area of the organic connecting agent can also accelerate the mass transfer of the photocatalytic process. However, the absorption of the UiO-66-NH2 in the visible light range is weak, which leads to poor utilization of sunlight, and the separation rate of the electron-hole pair is not high, resulting in unsatisfactory photocatalytic performance.

[0004] Therefore, there is an urgent need for a new technical solution to solve the above technical problems. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a core-shell structure Fe 0 Preparation method of composite photo-Fenton catalyst of UiO-66-NH2 and use method thereof.

[0006] The above technical purpose of the present application is realized by the following technical solution: a core-shell structure Fe 0 The preparation method of the composite photo-Fenton catalyst of UiO-66-NH2 comprises the following steps:

[0007] Step 1: preparing metal organic framework UiO-66-NH2 by hydrothermal synthesis method

[0008] Zirconium tetrachloride (ZrCl4) and 2-amino terephthalic acid (NH2-BDC) are added into N,N-dimethylformamide (DMF) to dissolve and mix, and acid is added to stir uniformly, the obtained metal salt organic ligand solution is transferred to a reaction kettle, ultrasonic treatment is performed, and then the reaction kettle is placed in an oven to perform hydrothermal synthesis, after cooling to room temperature, filtration is performed, and the sample is washed with DMF and anhydrous methanol to obtain the metal organic framework UiO-66-NH2.

[0009] Step 2: adding an iron source for compounding

[0010] The UiO-66-NH2 prepared in step 1 is mixed with an iron source in ultrapure water and oscillated to perform compounding.

[0011] Step 3: preparing Fe@UiO-66-NH2 composite catalyst by using a sodium borohydride reduction method 0 @UiO-66-NH2 composite catalyst

[0012] The compounded sample in step 2 is added to sodium borohydride (NaBH4) for reduction, and after acid washing, filtration and vacuum drying, the Fe@UiO-66-NH2 composite catalyst is obtained. 0 @UiO-66-NH2 composite catalyst.

[0013] The application is further provided as follows: in step 1, the molar ratio of ZrCl4 to NH2-BDC is (0.2-2):1.

[0014] The application is further provided as follows: in step 1, the acid refers to one of acetic acid, hydrochloric acid and glacial acetic acid, or a mixture of any two or three of the above acids.

[0015] The application is further provided as follows: in step 1, the ultrasonic treatment time is 0.5-3h, the hydrothermal synthesis temperature is 100-160℃, and the reaction time is 20-36h.

[0016] The application is further provided as follows: in step 1, the washing specifically refers to that the sample after filtration and centrifugation is sequentially washed with DMF and anhydrous methanol for three times, and after washing, the sample is soaked in anhydrous methanol for 1-3h.

[0017] The application is further provided as follows: in step 2, the iron source is one of anhydrous ferric chloride (FeCl3), iron nitrate nonahydrate (Fe(NO3)3·9H2O) and ferric sulfate (Fe2(SO4)3).

[0018] The application is further provided as follows: in step 2, the mass ratio of UiO-66-NH2 to the iron source is (0.1-1):1.

[0019] The application is further provided that the mixing and oscillation operation in step two is oscillation for 12-24 hours at 25 DEG C in a constant temperature oscillation box.

[0020] The application is further provided that the mass ratio of UiO-66-NH2 to NaBH4 added in step 3 is (1-5):1, the reduction time is 1-3 hours, and the flushing operation is repeated flushing three times with the acid used in step 1.

[0021] A core-shell structure Fe 0 The application further provides a use method of the UiO-66-NH2 composite Fenton catalyst, which is prepared by the preparation method in any one of the above and is in a composite nanofiber material state, is put into a water environment, and is used for catalytic degradation of organic pollutants in the water body.

[0022] The application has the following beneficial effects:

[0023] 1. The Fe 0 The UiO-66-NH2 composite catalyst can be prepared by hydrothermal synthesis and chemical reduction, and has simple preparation method and mild preparation condition. Based on the complexation and confinement of the metal organic framework, the ZVI is uniformly dispersed on the framework and the surface of the UiO-66-NH2, good composite of the material in the microcosmic view is realized, the particles are not easy to fall off, and excellent structural stability is achieved.

[0024] 2. The introduction of the ZVI can widen the response of the UiO-66-NH2 in the visible light range, reduce the recombination rate of the electron-hole pairs, and then improve the catalytic activity, so that the Fe 0 The UiO-66-NH2 also has good light stability and recyclable regeneration performance. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The micro scanning electron microscope image of the Fe 0 @UiO-66-NH2 composite catalyst prepared in embodiment 1 of the application;

[0026] Figure 2 The EDS element distribution diagram of carbon, oxygen, zirconium and iron on the Fe 0 @UiO-66-NH2 composite catalyst prepared in embodiment 1 of the application;

[0027] Figure 3 The UV-visible diffuse reflectance spectrum of the Fe 0 @UiO-66-NH2 composite catalyst prepared in embodiment 1 of the application;

[0028] Figure 4 The Fe0 @Degradation curve of antibiotic ciprofloxacin (CIP) in water by UiO-66-NH2 composite catalysts;

[0029] Figure 5 Fe 0 @Variation of photocatalytic activity of UiO-66-NH2 composite catalyst in cyclic test. DETAILED DESCRIPTION

[0030] The application will be further described in detail below with reference to the accompanying drawings.

[0031] Example 1

[0032] Fe 0 @The preparation method of the UiO-66-NH2 composite photo-Fenton catalyst comprises the following steps: 0.233g ZrCl4 and 0.181g NH2-BDC are added to 20ml DMF to be dissolved and mixed at room temperature, 0.25ml HCl is added to the mixed solution and stirred uniformly, then transferred into a polytetrafluoroethylene liner, and after ultrasonic treatment for 1h, the reaction kettle is placed in an oven to react at a temperature of 120℃ for 24h. After cooling to room temperature, filtration is performed, and then washing with DMF, anhydrous methanol is performed for 3 times respectively, and finally immersed in anhydrous methanol for 1h, suction filtration, and vacuum drying at 60℃ for 12h to obtain the UiO-66-NH2.

[0033] 0.3g of the prepared UiO-66-NH2 sample and 1.2g of FeCl3 are added to 60ml of ultrapure water, placed in a constant temperature shaking box for 12h, and then 0.1g of NaBH4 is added for reduction for 2h, and then the final sample is obtained after washing with HCl, filtration and drying.

[0034] The scanning electron microscope image ( Figure 1 ) shows that under the conditions of example 1, the Fe 0 @The UiO-66-NH2 nanoparticles are in a state of agglomeration, have obvious crystal structure and boundaries, and the surface is rough, but the regular octahedral structure is not obvious. The crystal structure of the UiO-66-NH2 can be finely controlled by controlling the amount of the added adjusting agent, so as to prepare monodisperse and structurally complete crystal particles. Figure 2 The EDS element distribution map shows that there are elements such as C, O, Zr and Fe in the composite material, and they are uniformly distributed. The ultraviolet-visible diffuse reflectance spectrum ( Figure 3 ) shows that the Fe 0 @The UiO-66-NH2 expands the absorption band to 610nm.

[0035] The antibiotic CIP is used as a model pollutant to evaluate the catalyst Fe 0Photocatalytic degradation performance of UiO-66-NH2. In the photocatalytic reactor, 0.05 g Fe 0 @UiO-66-NH2 was added into 100 mL CIP aqueous solution with a concentration of 31 mg·L -1 The mixed solution was magnetically stirred in the dark for 1 h to achieve adsorption-desorption equilibrium. A xenon lamp with a power of 300 W was used as a light source to simulate sunlight. Under UV-Vis light irradiation, complete removal of CIP could be achieved within 20 min, and the removal rate could reach 80% within 5 min. Figure 4 The concentration-time curve of CIP aqueous solution in the process of photocatalytic degradation (PS represents photolysis reaction, and PCFT represents photocatalytic degradation reaction).

[0036] After the catalytic degradation reaction, the sample was collected by filtration, washing, and vacuum drying at 60℃ for 12 h. The collected Fe 0 @UiO-66-NH2 sample was subjected to a cycle experiment to test the Fe 0 @UiO-66-NH2 sample was subjected to a cycle experiment to test the Fe 0 @UiO-66-NH2 still maintained 100% removal rate of CIP after 5 cycles Figure 5 ), indicating that Fe 0 @UiO-66-NH2 has high stability and reproducibility in the degradation and removal of organic matter, and can be reused after simple filtration, washing, and drying.

[0037] Fe 0 @UiO-66-NH2 sample has good light stability, structural stability, and cycle regeneration performance, and can be applied to the catalytic degradation of organic pollutants in water environment.

[0038] Example 2

[0039] A Fe 0 @UiO-66-NH2 composite photocatalyst preparation method, comprising the following steps: 0.0745 g of zirconium tetrachloride (ZrCl4) and 0.072 g of 2-amino terephthalic acid (NH2-BDC) are added to 50 ml of N, N-dimethylformamide (DMF) and dissolved at room temperature. The mixture is stirred uniformly, transferred to a polytetrafluoroethylene liner, ultrasonicated for 0.5 h, and then placed in an oven at a temperature of 120℃ for 24 h. After cooling to room temperature, filtration is performed, and the sample is rinsed with DMF, anhydrous methanol for 3 times, and finally soaked in anhydrous methanol for 1 h. After suction filtration, vacuum drying at 60℃ can obtain UiO-66-NH2.

[0040] 0.1 g of the prepared UiO-66-NH2 sample and 0.3 g of Fe2(SO4)3 were added to 60 ml of ultrapure water, placed in a constant temperature shaking box for 12 h, after filtration, 0.05 g of NaBH4 was added for reduction for 1 h, after washing with glacial acetic acid, filtration and drying to obtain the final sample.

[0041] Example 3

[0042] A Fe 0 The preparation method of the UiO-66-NH2 composite photo-Fenton catalyst comprises the following steps: 0.268 g of zirconium tetrachloride (ZrCl4) and 0.250 g of 2-amino terephthalic acid (NH2-BDC) are added to 50 ml of N, N-dimethylformamide (DMF) and dissolved and mixed at room temperature, 2 ml of HCl is added to the mixed solution and stirred uniformly, transferred to a polytetrafluoroethylene liner, ultrasonically treated for 2 h, and then the reaction kettle is placed in an oven and reacted at a temperature of 120°C for 24 h. After cooling to room temperature, filtration is performed, and washing with DMF, anhydrous methanol is performed three times respectively, and finally soaking in anhydrous methanol for 2 h, suction filtration, and vacuum drying at 80°C for 12 h to obtain UiO-66-NH2.

[0043] 0.3 g of the prepared UiO-66-NH2 sample and 1.2 g of Fe(NO3)3·9H2O are added to 60 ml of ultrapure water, placed in a constant temperature shaking box for 12 h, after filtration, 0.1 g of NaBH4 is added for reduction for 2 h, washed with HCl, and then filtered and dried to obtain the final sample.

[0044] Example 4

[0045] A Fe 0 The preparation method of the UiO-66-NH2 composite photo-Fenton catalyst comprises the following steps: 0.233 g of ZrCl4 (1 mmol) and 0.181 g of NH2-BDC (1 mmol) are added to 5 ml of N, N-dimethylformamide (DMF) and dissolved and mixed at room temperature, 10 ml of acetic acid is added to the mixed solution and stirred uniformly, transferred to a polytetrafluoroethylene liner, ultrasonically treated for 1 h, and then the reaction kettle is placed in an oven and reacted at a temperature of 140°C for 20 h. After cooling to room temperature, filtration is performed, and washing with DMF, anhydrous methanol is performed three times respectively, and finally soaking in anhydrous methanol for 1 h, suction filtration, and vacuum drying at 60°C for 14 h to obtain UiO-66-NH2.

[0046] 0.3 g of the prepared UiO-66-NH2 sample and 1.2 g of FeCl3 are added to 60 ml of ultrapure water, placed in a constant temperature shaking box for 12 h, after filtration, 0.1 g of NaBH4 is added for reduction for 2 h, washed with acetic acid, and then filtered and dried to obtain the final sample.

[0047] Example 5

[0048] A core-shell structured Fe 0 The preparation method of the UiO-66-NH2 composite photo-Fenton catalyst comprises the following steps: 0.233 g of ZrCl4(1 mmol) and 0.181 g of NH2-BDC (1 mmol) are added to 20 ml of DMF to dissolve and mix at room temperature, 0.25 ml of HCl is added to the mixed solution and stirred uniformly, transferred into a polytetrafluoroethylene liner, after ultrasonic treatment for 1 h, the reaction kettle is placed in an oven to react at a temperature of 160 °C for 20 h. After cooling to room temperature, filtration is performed, and washing is performed with DMF, anhydrous methanol, respectively, 3 times, and finally immersed in anhydrous methanol for 3 h, suction filtration, vacuum drying at 50 °C for 24 h, and the UiO-66-NH2 is obtained.

[0049] 0.3 g of the prepared UiO-66-NH2 sample and 0.6 g of Fe2(SO4)3 are added to 60 ml of ultrapure water, placed in a constant temperature shaking box for 16 h, after filtration, 0.3 g of NaBH4 is added for reduction for 3 h, washed with HCl, and then filtered and dried to obtain the final sample.

[0050] Example 6

[0051] A core-shell structured Fe 0 The preparation method of the UiO-66-NH2 composite photo-Fenton catalyst comprises the following steps: 0.233 g of ZrCl4(1 mmol) and 0.181 g of NH2-BDC (1 mmol) are added to 20 ml of DMF to dissolve and mix at room temperature, 0.25 ml of HCl is added to the mixed solution and stirred uniformly, transferred into a polytetrafluoroethylene liner, after ultrasonic treatment for 1 h, the reaction kettle is placed in an oven to react at a temperature of 160 °C for 20 h. After cooling to room temperature, filtration is performed, and washing is performed with DMF, anhydrous methanol, respectively, 3 times, and finally immersed in anhydrous methanol for 3 h, suction filtration, vacuum drying at 50 °C for 24 h, and the UiO-66-NH2 is obtained.

[0052] 0.3 g of the prepared UiO-66-NH2 sample and 0.6 g of Fe2(SO4)3 are added to 60 ml of ultrapure water, placed in a constant temperature shaking box for 16 h, after filtration, 0.3 g of NaBH4 is added for reduction for 3 h, washed with HCl, and then filtered and dried to obtain the final sample.

[0053] Comparative example

[0054] 0.233 g ZrCl4and 0.181 g NH2-BDC were added into 20 ml DMF to dissolve the mixture at room temperature, 0.25 ml HCl was added into the mixture to stir uniformly, and then the mixture was transferred into a polytetrafluoroethylene liner, and after ultrasonic treatment for 1 h, the reaction kettle was placed into an oven to react at a temperature of 120 °C for 24 h. After cooling to room temperature, filtration was performed, and the sample was rinsed with DMF, anhydrous methanol for 3 times respectively, and finally soaked in anhydrous methanol for 1 h, suction filtration was performed, and the sample was dried at 60 °C under vacuum for 12 h to obtain a UiO-66-NH2 sample. The photocatalytic degradation efficiency of the sample on CIP was only 10% within 30 min.

[0055] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments according to the needs without creative contributions, as long as the modifications are within the scope of the claims of the present application.

Claims

1. A core-shell structure Fe 0 @UiO-66-NH2 composite photo-Fenton catalyst in photocatalysis, for catalytic degradation of organic pollutants in water body, characterized by: The core-shell structure Fe 0 The preparation method of the UiO-66-NH2 composite photo-Fenton catalyst specifically comprises the following steps: Step 1: preparing metal-organic framework UiO-66-NH2 by hydrothermal synthesis method Zirconium tetrachloride (ZrCl4) and 2-amino terephthalic acid (NH2-BDC) are added to N,N-dimethylformamide (DMF) to dissolve and mix, and acid is added to stir evenly, the obtained metal salt organic ligand solution is transferred to a reaction kettle, ultrasonic treatment is performed, and then placed in an oven for hydrothermal synthesis, after cooling to room temperature, filtration is performed, and then washed with DMF and anhydrous methanol to obtain metal-organic framework UiO-66-NH2; Step 2: adding an iron source for compounding UiO-66-NH2 prepared in step 1 is mixed with an iron source in ultrapure water and oscillated for compounding. Step 3: Preparation of Fe using sodium borohydride reduction method 0 @UiO-66-NH2 composite catalyst The complexed sample in step 2 was added to sodium borohydride (NaBH4) for reduction, and after acid washing, filtration, and vacuum drying, Fe 0 @UiO-66-NH2 complex catalyst.

2. A core-shell structure Fe 0 @The application relates to application of a composite photo-Fenton catalyst of UiO-66-NH2 in photocatalysis, characterized by comprising the following steps: In step 1, the molar ratio of ZrCl4 to NH2-BDC is (0.2-2):

1.

3. A core-shell structure Fe 0 @The application relates to application of a UiO-66-NH2 composite photo-Fenton catalyst in photocatalysis, characterized by comprising the following steps: The acid in step 1 refers to acetic acid or hydrochloric acid.

4. A core-shell structure Fe 0 @The application relates to application of a composite photo-Fenton catalyst of UiO-66-NH2 in photocatalysis, characterized by comprising the following steps: In step 1, the ultrasonic treatment time is 0.5-3 h; the hydrothermal synthesis temperature is 100-160℃, and the reaction time is 20-36 h.

5. The core-shell structured Fe according to claim 1. 0 @The application of the UiO-66-NH2 composite photo-Fenton catalyst in photocatalysis, wherein the washing in step 1 specifically refers to sequentially washing the sample after filtration and centrifugation with DMF and anhydrous methanol for three times each, and then soaking the sample in anhydrous methanol for 1-3 h after the washing is completed.

6. A core-shell structure Fe 0 @The application relates to application of a composite photo-Fenton catalyst of UiO-66-NH2 in photocatalysis, characterized by comprising the following steps: In step 2, the iron source is one of anhydrous ferric chloride (FeCl3), iron nitrate nonahydrate (Fe(NO3)3·9H2O), and ferric sulfate (Fe2(SO4)3).

7. A core-shell structured Fe 0 @The application relates to application of a composite photo-Fenton catalyst of UiO-66-NH2 in photocatalysis, characterized by comprising the following steps: In step 2, the mass ratio of UiO-66-NH2 to the iron source is (0.1-1):

1.

8. A core-shell structure Fe 0 @The application relates to application of a composite photo-Fenton catalyst of UiO-66-NH2 in photocatalysis, characterized by comprising the following steps: In step 2, the mixing and oscillation operation refers to oscillation in a constant-temperature oscillation box at 25℃ for 12 h-24 h.

9. A core-shell structured Fe 0 @The application of the UiO-66-NH2 composite photo-Fenton catalyst in photocatalysis is characterized by: In step 3, the mass ratio of UiO-66-NH2 to the added NaBH4 is (1-5):1; the reduction time is 1-3 h; the acid washing operation is repeated three times with the acid used in step 1; and the vacuum drying refers to vacuum drying at 50℃-80℃ for 10 h-14 h.

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