Preparation method and application of ferriporphyrin-artificial humic acid nanocarbon composite photocatalyst

Abstract

The invention discloses a preparation method and application of a ferriporphyrin-artificial humic acid nanocarbon composite photocatalyst, and relates to a preparation method and application of a photocatalyst. The invention aims to solve the problems of low catalytic activity, poor dispersibility and poor degradation effect on organic matters of the existing photocatalyst. The method comprises the following steps: 1, preparing an iron-based porphyrin metal organic framework material with a three-dimensional space structure; 2, preparing highly dispersed artificial humic acid nano carbon; and 3, compounding. The artificial humic acid nanocarbon has abundant functional groups and a relatively large specific surface area, has a good adsorption effect on pollutants in water, and in addition, the artificial humic acid nanocarbon improves the dispersity and photocatalytic efficiency of a single iron-based porphyrin metal organic framework material. Artificial humic acid nanocarbon and a three-dimensional iron-based porphyrin metal organic framework are compounded, the photocatalytic characteristic of the iron-based porphyrin metal organic framework is combined and improved, the dispersity of the composite material is changed by utilizing the adsorption characteristic of nanocarbon, and the composite material has good performance in degradation of organic pollutants.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a photocatalyst. Background Art

[0002] Pollutants in water come from many sources. Many industrial production processes produce wastewater with organic pollutants. The wastewater from printing and dyeing factories contains a large amount of unreacted dyes, such as Congo red and rhodamine B. These organic dyes have complex components, are difficult to degrade, and have strong toxicity. In the petrochemical industry, since petroleum itself contains polycyclic aromatic hydrocarbons (such as naphthalene), high-temperature heating projects will release these substances. If these wastes are not handled properly, they will enter the water body. These organic pollutants are very harmful to the human body, so the issue of water treatment has always been a hot topic of great concern to people.

[0003] At present, various physical, chemical and biological remediation technologies have been developed for the remediation of organic pollutants in water bodies. Among them, photocatalytic degradation has great potential in removing pollutants in water due to its advantages of environmental protection, high efficiency and direct use of sunlight, and has become a hot topic of research. Common photocatalytic technologies include modification by precious metal deposition. The principle is to deposit precious metals (such as Pt, Au, Ag, etc.) on the surface of the photocatalyst, changing the surface electronic structure of the photocatalyst. Because precious metal nanoparticles have good conductivity, they can capture photogenerated electrons, thereby improving the photocatalytic efficiency. In addition, there are also semiconductor composite modification by combining multiple semiconductor materials together, and using their different band structures to achieve effective separation of photogenerated carriers. However, the disadvantage of using precious metals is that it will increase the cost of photocatalysts and limit their scope of use. Some catalysts also have the problem of poor stability and poor selectivity of photocatalytic reactions. For example, TiO2 may cause changes in the crystal structure under long-term illumination, reducing its catalytic performance. Therefore, it is necessary to study a photocatalyst with strong stability, certain reaction selectivity and low cost.

[0004] As a material with photocatalytic properties, iron-based porphyrin metal organic framework (MOF) has the advantages of low toxicity, low secondary pollution during the photocatalytic process, and environmental friendliness. It has been widely used in the removal process of difficult-to-degrade organic matter. However, the stability and dispersibility of iron-based porphyrin MOF are poor, which will affect the contact efficiency between the catalyst and the degradation product. Its catalytic activity still needs to be improved, and it usually needs to be compounded with other materials to make up for the above shortcomings. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of low catalytic activity, poor dispersibility and poor degradation effect of organic matter of existing photocatalysts, and to provide a preparation method and application of an iron porphyrin@artificial humic acid nano-carbon composite photocatalyst.

[0006] The invention firstly prepares an iron-based porphyrin metal organic framework material MOF (3D-Fe-TCPP) with a three-dimensional spatial structure through a hydrothermal reaction, then places artificial humic acid in a tubular furnace to sinter artificial humic acid nanocarbon (MSNC), and then transfers the two substances to a reactor for hydrothermal treatment again, and obtains an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst (3D-Fe-TCPP-MSNC). The preparation method of the invention is simple and easy to operate, and the artificial humic acid is sintered into nanocarbon, which can enhance the stability and activity of the catalyst to a certain extent. The obtained iron porphyrin@artificial humic acid nanocarbon composite photocatalyst is used to perform photocatalysis on naphthalene, Congo red or rhodamine B, and has an excellent degradation effect on complex organic pollutants such as polycyclic aromatic hydrocarbons.

[0007] A method for preparing an iron porphyrin@artificial humic acid nano-carbon composite photocatalyst is specifically completed by the following steps:

[0008] 1. Preparation of iron-based porphyrin metal organic framework materials with three-dimensional spatial structure;

[0009] ①, mix trivalent iron salt, polyvinyl pyrrolidone, trifluoroacetic acid, N,N-dimethylformamide and anhydrous ethanol, and disperse them uniformly by ultrasonication to obtain a precursor solution A;

[0010] ②, tetrakis(4-carboxyphenyl)porphyrin, N,N-dimethylformamide and anhydrous ethanol were mixed and uniformly dispersed by ultrasonication to obtain a precursor solution B;

[0011] ③. Precursor solution A and precursor solution B are mixed, dispersed uniformly by ultrasonication, and then transferred into a hydrothermal reactor for hydrothermal reaction at 90° C. to 100° C. for a period of time, and then centrifuged, washed, dried, and ground to obtain a three-dimensional iron-based porphyrin metal organic framework material (3D-Fe-TCPP);

[0012] 2. Preparation of highly dispersed artificial humic acid nanocarbon:

[0013] Artificial humic acid, urea, zinc chloride and potassium chloride are mixed evenly, then placed in a tube furnace and calcined in nitrogen for a period of time, cooled to room temperature, washed with hydrochloric acid and deionized water in sequence, and finally dried and ground to obtain highly dispersed artificial humic acid nanocarbon (MSNC);

[0014] 3. Preparation of iron porphyrin@artificial humic acid nanocarbon composite photocatalyst:

[0015] The three-dimensional iron-based porphyrin metal organic framework material and highly dispersed artificial humic acid nanocarbon are dissolved in N,N-dimethylformamide, stirred evenly, and then transferred into a hydrothermal reactor for hydrothermal reaction at 90°C to 95°C for a period of time, and then centrifuged, washed, and dried to obtain an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst (3D-Fe-TCPP-MSNC).

[0016] An iron porphyrin@artificial humic acid nanocarbon composite photocatalyst is used to remove organic matter.

[0017] Principle of the present invention:

[0018] Artificial humic acid (AHA) has abundant functional groups, which can improve the activity and selectivity of catalytic reactions; the artificial humic acid (AHA) used in the present invention is obtained by hydrothermal reaction of powder obtained by crushing waste straw with potassium hydroxide; the molten salt method can ensure the carbonization of humic acid while retaining its functional groups, thereby obtaining a carbon-based material with abundant surface functional groups; artificial humic acid is obtained by simulating the formation process of humic acid in the natural environment or modifying natural humic acid. Artificial humic acid contains abundant functional groups, such as carboxyl, hydroxyl, etc. These functional groups can interact with the metal nodes or organic ligands of the iron-based porphyrin MOF, introduce more active sites on the surface of the iron-based porphyrin MOF, thereby improving its adsorption and activation ability for reactant molecules and promoting the photocatalytic reaction. Combined with the porous structure and catalytic activity of the iron-based porphyrin MOF and the functional group characteristics of artificial humic acid, such as adsorption performance and complexing ability for metal ions. By combining the two, the adsorption capacity of the catalyst for the reactants can be improved, making it easier for the reactants to be enriched on the catalyst surface, thereby improving the reaction. After the artificial humic acid nanocarbon is combined with the iron-based porphyrin MOF, the high dispersibility of the artificial humic acid nanocarbon will enhance the dispersibility of the composite material. The present invention combines the three-dimensional iron-based porphyrin MOF with the artificial humic acid nanocarbon to enhance the stability and activity of the photocatalyst.

[0019] Advantages of the present invention:

[0020] 1. The iron-based porphyrin metal organic framework material has a unique porous structure and a large specific surface area, which can provide abundant active sites and is conducive to the catalytic reaction. The introduction of artificial humic acid nanocarbon further enhances the material's ability to absorb light and reduces the energy required for photocatalysis, so that the composite photocatalyst can exhibit excellent photocatalytic activity under visible light and can efficiently degrade target substances such as organic pollutants.

[0021] Second, the composite structure of the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst in the present invention effectively improves the stability problem of a single iron-based MOF. A stable chemical bond or interaction is formed between the artificial humic acid nanocarbon and the iron-based porphyrin metal organic framework material, enhancing its stability, so that the composite photocatalyst can maintain a high catalytic activity and reduce the cost of use;

[0022] 3. The present invention provides a new way to increase the value of metal organic frameworks and artificial humic acid, and the artificial humic acid used is relatively low in cost, which is in line with the concept of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a scanning electron microscope photograph of the three-dimensional iron-based porphyrin metal organic framework material prepared in step 1 of Example 1;

[0024] Figure 2 This is a scanning electron microscope photo of the artificial humic acid nanocarbon prepared in step 2 of Example 1;

[0025] Figure 3 This is a scanning electron microscope photograph of the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in step 3 of Example 1;

[0026] Figure 4 This is an element spectrum photo of the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared in step 3 of Example 1;

[0027] Figure 5 X-ray diffraction patterns of the three-dimensional iron-based porphyrin metal organic framework material, artificial humic acid nanocarbon and iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in Example 1;

[0028] Figure 6 Fourier transform infrared spectra of the three-dimensional iron-based porphyrin metal organic framework material, artificial humic acid nanocarbon and iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in Example 1;

[0029] Figure 7 The catalytic reduction efficiency curve of naphthalene by the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared by step 3 of Example 1 in Application Example 1 is shown;

[0030] Figure 8 The degradation curve of organic dyes by the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared in step 3 of Example 1 in Application Examples 2 to 3 is shown in FIG. a, which is the catalytic reduction efficiency curve of rhodamine B in Application Example 2, and b, which is the catalytic reduction efficiency curve of Congo red in Application Example 3;

[0031] Fig. 9This is a bar graph showing the removal rates of naphthalene, rhodamine B and Congo red using the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared in step 3 of Example 1 in Application Examples 1 to 3. DETAILED DESCRIPTION

[0032] Specific implementation method 1: This implementation method is a method for preparing an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst, which is specifically completed by the following steps:

[0033] 1. Preparation of iron-based porphyrin metal organic framework materials with three-dimensional spatial structure;

[0034] ①, mix trivalent iron salt, polyvinyl pyrrolidone, trifluoroacetic acid, N,N-dimethylformamide and anhydrous ethanol, and disperse them uniformly by ultrasonication to obtain a precursor solution A;

[0035] ②, tetrakis(4-carboxyphenyl)porphyrin, N,N-dimethylformamide and anhydrous ethanol were mixed and uniformly dispersed by ultrasonication to obtain a precursor solution B;

[0036] ③. Precursor solution A and precursor solution B are mixed, dispersed uniformly by ultrasonication, and then transferred into a hydrothermal reactor for hydrothermal reaction at 90°C to 100°C for a period of time, and then centrifuged, washed, dried, and ground to obtain a three-dimensional iron-based porphyrin metal organic framework material;

[0037] 2. Preparation of highly dispersed artificial humic acid nanocarbon:

[0038] Artificial humic acid, urea, zinc chloride and potassium chloride are mixed evenly, then placed in a tube furnace and calcined in nitrogen for a period of time, cooled to room temperature, washed with hydrochloric acid and deionized water in sequence, and finally dried and ground to obtain highly dispersed artificial humic acid nanocarbon;

[0039] 3. Preparation of iron porphyrin@artificial humic acid nanocarbon composite photocatalyst:

[0040] The three-dimensional iron-based porphyrin metal organic framework material and highly dispersed artificial humic acid nanocarbon are dissolved in N,N-dimethylformamide, stirred evenly, and then transferred into a hydrothermal reactor for hydrothermal reaction at 90°C to 95°C for a period of time, and then centrifuged, washed, and dried to obtain an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst.

[0041] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the ferric iron salt described in step 1① is ferric nitrate nonahydrate; the mass ratio of the ferric iron salt described in step 1① to polyvinyl pyrrolidone is (2-2.1):(5-5.2); the mass volume ratio of the ferric iron salt, trifluoroacetic acid, N,N-dimethylformamide and anhydrous ethanol described in step 1① is (0.0450g-0.0451g):(0.498mL-0.499mL):(112.14mL-112.15mL):(37.38mL-37.39mL). The other steps are the same as those in specific embodiment 1.

[0042] Specific embodiment three: This embodiment differs from specific embodiment one or two in that: the mass volume ratio of tetrakis (4-carboxyphenyl) porphyrin, N, N-dimethylformamide and anhydrous ethanol described in step one ② is (0.055g~0.0551g): (37.38mL~37.39mL): (12.46mL~12.47mL); the time of the hydrothermal reaction described in step one ③ is 23h~24h; the volume ratio of the precursor solution A and the precursor solution B described in step one ③ is (150~150.02): (49.84~49.86); the solvent used for washing described in step one ③ is N, N-dimethylformamide and deionized water; the drying temperature is 60℃~80℃. The other steps are the same as specific embodiment one or two.

[0043] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the mass ratio of artificial humic acid, urea, zinc chloride and potassium chloride described in step 2 is (4.50g-4.51g):(4.50g-4.51g):(29.91g-29.92g):(15.09g-15.10g); the calcination temperature described in step 2 is 400°C-500°C, and the calcination time is 4h-5h. The other steps are the same as those of specific embodiments 1 to 3.

[0044] Specific implementation method five: The difference between this implementation method and specific implementation methods one to four is that the preparation method of artificial humic acid described in step two is completed in the following steps: first, wash, dry and crush the biomass waste to obtain biomass waste powder; disperse the biomass waste powder and the catalyst in deionized water, and then transfer them to a hydrothermal reactor, and then put the hydrothermal reactor into an oven for hydrothermal reaction, and then cool to room temperature to obtain a solid-liquid mixture; filter the solid-liquid mixture and collect the liquid; use hydrochloric acid to adjust the pH value of the liquid to 1, let it stand to precipitate solids, and then use deionized water to wash the precipitated solid matter to neutrality, dry it, and grind it into powder to obtain artificial humic acid. The other steps are the same as specific implementation methods one to four.

[0045] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that: the biomass waste is corn stalks; the catalyst is potassium hydroxide; the mass volume ratio of the biomass waste powder, the catalyst and deionized water is 8g:2g:100mL; the temperature of the hydrothermal reaction is 200℃~250℃, and the time of the hydrothermal reaction is 24h~30h. The other steps are the same as those of specific embodiments 1 to 5.

[0046] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that: the mass ratio of the three-dimensional iron-based porphyrin metal organic framework material and the highly dispersed artificial humic acid nanocarbon described in step 3 is (2 to 4): 1; the volume ratio of the mass of the three-dimensional iron-based porphyrin metal organic framework material described in step 3 to N, N-dimethylformamide is (0.2g to 0.4g): (130mL to 150mL); the time of the hydrothermal reaction described in step 3 is 23h to 24h; the solvent used for washing described in step 3 is N, N-dimethylformamide and deionized water; the drying temperature is 60°C to 80°C. The other steps are the same as specific embodiments 1 to 6.

[0047] Specific embodiment eight: This embodiment is an iron porphyrin@artificial humic acid nano-carbon composite photocatalyst for removing organic matter.

[0048] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that: an iron porphyrin@artificial humic acid nano-carbon composite photocatalyst is used to remove organic matter, which is specifically completed by the following steps:

[0049] An iron porphyrin@artificial humic acid nano-carbon composite photocatalyst is added to a solution containing organic matter, and a photocatalytic reduction reaction is carried out under light to obtain a solution with organic matter removed. The other steps are the same as those in the first to eighth embodiments.

[0050] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that: the organic matter is an organic dye or polycyclic aromatic hydrocarbon; the organic dye is rhodamine B or Congo red; the polycyclic aromatic hydrocarbon is naphthalene; the dosage of the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst is 0.2g / L to 0.21g / L; the time of the photocatalytic reduction reaction is 10min to 120min; the illumination is irradiation by a xenon lamp light source. The other steps are the same as those of specific embodiments 1 to 9.

[0051] The following examples are used to verify the beneficial effects of the present invention:

[0052] Example 1: A method for preparing an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst is specifically completed by the following steps:

[0053] 1. Preparation of three-dimensional iron-based porphyrin metal organic framework materials with three-dimensional spatial structure;

[0054] ①、Nonahydrate iron nitrate (Fe(NO3) 3· 9H2O), polyvinyl pyrrolidone (PVP), trifluoroacetic acid, N,N-dimethylformamide and anhydrous ethanol were mixed and ultrasonically dispersed for 30 minutes to obtain a precursor solution A;

[0055] The iron nitrate nonahydrate (Fe(NO3) 3· The mass ratio of 9H2O) to polyvinylpyrrolidone (PVP) is 2:5;

[0056] The iron nitrate nonahydrate (Fe(NO3) 3· 9H2O), trifluoroacetic acid, N,N-dimethylformamide and anhydrous ethanol in a mass volume ratio of 0.045 g:0.498 mL:112.14 mL:37.38 mL;

[0057] ②, tetrakis(4-carboxyphenyl)porphyrin (TCPP), N,N-dimethylformamide (DMF) and anhydrous ethanol were mixed and ultrasonically dispersed for 30 minutes to obtain a precursor solution B;

[0058] The mass volume ratio of tetrakis(4-carboxyphenyl)porphyrin, N,N-dimethylformamide and anhydrous ethanol described in step 1② is 0.055g:37.38mL:12.46mL;

[0059] ③. Precursor solution A and precursor solution B were mixed, ultrasonically dispersed for 15 minutes, and then transferred to a hydrothermal reactor for hydrothermal reaction at 90°C for 24 hours, and then centrifuged. The solid matter was washed three times with N,N-dimethylformamide and deionized water respectively, and then vacuum dried at 60°C for 12 hours, and ground with an agate mortar to obtain a three-dimensional iron-based porphyrin metal organic framework material (3D-Fe-TCPP);

[0060] The volume ratio of the precursor solution A and the precursor solution B described in step 1③ is 150mL:49.84mL;

[0061] 2. Preparation of highly dispersed artificial humic acid nanocarbon:

[0062] 4.50 g of artificial humic acid, 4.50 g of urea, 29.91 g of zinc chloride and 15.09 g of potassium chloride were mixed and ground, then placed in a tube furnace, flushed with nitrogen for 1 hour, then heated from room temperature to 400°C at a heating rate of 2°C / min, maintained at 400°C for 4 hours under a nitrogen atmosphere, and cooled to room temperature to obtain a reaction product; first, the reaction product was immersed in 1.2 mol / L hydrochloric acid and stirred and washed for 24 hours, then taken out and immersed in 1.2 mol / L hydrochloric acid again and stirred and washed for 24 hours, then washed with deionized water for several times to remove residual hydrochloric acid, and then vacuum dried at 60°C for 24 hours, and finally ground into powder using an agate mortar to obtain highly dispersed artificial humic acid nanocarbon (MSNC);

[0063] The preparation method of the artificial humic acid described in step 2 is specifically completed according to the following steps:

[0064] First, the biomass waste is washed, dried and crushed to obtain biomass waste powder; the biomass waste powder and the catalyst are dispersed in deionized water, and then transferred to a hydrothermal reactor, and then the hydrothermal reactor is placed in an oven for hydrothermal reaction, and then cooled to room temperature to obtain a solid-liquid mixture; the solid-liquid mixture is filtered to collect the liquid; the pH value of the liquid is adjusted to 1 with hydrochloric acid, and the solid is precipitated by standing, and then the precipitated solid matter is washed with deionized water to neutrality, dried, and ground into powder with an agate mortar to obtain artificial humic acid (A-HA);

[0065] The mass volume ratio of the biomass waste powder, catalyst and deionized water is 8g:2g:100mL;

[0066] The biomass waste is corn stalks; the catalyst is potassium hydroxide; the temperature of the hydrothermal reaction is 200° C., and the time of the hydrothermal reaction is 24 hours;

[0067] 3. Preparation of iron porphyrin@artificial humic acid nanocarbon composite photocatalyst:

[0068] 0.20 g of three-dimensional iron-based porphyrin metal-organic framework material (3D-Fe-TCPP) and 0.05 g of highly dispersed artificial humic acid nanocarbon (MSNC) were dissolved in 130 mL of N,N-dimethylformamide, magnetically stirred for 30 min, and then transferred to a hydrothermal reactor for hydrothermal reaction at 90 °C for 24 h. The solid material was washed three times with N,N-dimethylformamide and deionized water respectively, and then vacuum dried at 60 °C for 12 h to obtain the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst (3D-Fe-TCPP-MSNC).

[0069] Figure 1This is a scanning electron microscope photograph of the three-dimensional iron-based porphyrin metal organic framework material prepared in step 1 of Example 1;

[0070] Figure 2 This is a scanning electron microscope photo of the artificial humic acid nanocarbon prepared in step 2 of Example 1;

[0071] Figure 3 This is a scanning electron microscope photograph of the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in step 3 of Example 1;

[0072] It can be clearly seen from the scanning electron microscope that the three-dimensional iron-based porphyrin metal organic framework material is a nanorod structure, the artificial humic acid nanocarbon is a highly dispersed block structure, and the composite structure is the successful combination of the iron-based porphyrin metal organic framework material and the artificial humic acid nanocarbon.

[0073] Figure 4 This is an element spectrum photo of the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared in step 3 of Example 1;

[0074] It can be clearly seen from the elemental energy spectrum that carbon, nitrogen, oxygen and iron elements are evenly distributed on the surface of the composite iron porphyrin@artificial humic acid nanocarbon, indicating the successful preparation of the material.

[0075] Figure 5 X-ray diffraction patterns of the three-dimensional iron-based porphyrin metal organic framework material, artificial humic acid nanocarbon and iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in Example 1;

[0076] From the X-ray diffraction pattern, it can be seen that 3D-Fe-TCPP and 3D-Fe-TCPP-MSNC have sharp peaks at 2θ=5°, and the 3D-Fe-TCPP-MSNC composite material contains the characteristic peaks of 3D-Fe-TCPP and MSNC, which proves the successful combination of the composite material.

[0077] Figure 6 Fourier transform infrared spectra of the three-dimensional iron-based porphyrin metal organic framework material, artificial humic acid nanocarbon and iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in Example 1;

[0078] From the Fourier transform infrared spectrum, we can see that 3D-Fe-TCPP and 3D-Fe-TCPP-MSNC have the highest peak at 499 cm -1 The stretching vibration peak of Fe-O appeared at , indicating the successful combination of 3D-Fe-TCPP and MSNC.

[0079] Application Example 1: The method for catalytically degrading naphthalene using the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared in step 3 of Example 1 is specifically completed in the following steps:

[0080] 12 mg of the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared in step 3 of Example 1 was added to 60 mL of a naphthalene solution having a concentration of 0.1 mmol / L, and the system was placed in a photochemical reactor with a light intensity of 250 W. The reaction was performed under natural light and 25° C. for 0 to 2 h. Samples were taken at specific times (0, 5, 10, 15, 30, 45, 60, 120 min), 4 mL of the solution was taken out and passed through a 0.22 μm filter membrane, and the filtered solution was then tested. The filtered naphthalene solution was respectively loaded into two liquid phase vials, and its peak area was observed by a high performance liquid chromatography tester;

[0081] As a control, the catalytic reduction efficiency curve of naphthalene is shown in Figure 2. Figure 7 As shown;

[0082] As a control, the catalytic reduction efficiency curve of naphthalene was shown in Figure 2. The irradiation was omitted and the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in step 3 of Example 1 was used alone. Figure 7 shown.

[0083] Application Example 2: A method for catalytically degrading rhodamine B using the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in step 3 of Example 1 is specifically completed in the following steps:

[0084] 12 mg of the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in step 3 of Example 1 was added to 60 mL of a 60 mg / L rhodamine B solution, and the system was placed in a photochemical reactor with a light intensity of 250 W. The reaction was carried out under natural light and 25° C. for 0 to 2 h. Samples were taken at specific times (0, 5, 10, 15, 30, 45, 60, 120 min), 4 mL of the solution was taken out and passed through a 0.22 μm filter membrane, and then the filtered solution was tested. The filtered rhodamine B solution was placed in a cuvette, and its absorbance was tested by a UV-visible spectrophotometer (λ=554 nm);

[0085] As a control, the catalytic reduction efficiency curve of rhodamine B is shown in Figure 2. Figure 8 As shown;

[0086] As a control, the irradiation was omitted and the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in step 3 of Example 1 was used alone. The catalytic reduction efficiency curve of rhodamine B is shown in FIG. Figure 8 shown.

[0087] Application Example 3: A method for catalytically degrading Congo red using the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in step 3 of Example 1 is specifically completed in the following steps:

[0088] 12 mg of the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared in step 3 of Example 1 was added to 60 mL of a 60 mg / L Congo red solution, and the system was placed in a photochemical reactor with a light intensity of 250 W. The reaction was carried out under natural light and 25° C. for 0 to 2 h. Samples were taken at specific times (0, 5, 10, 15, 30, 45, 60, 120 min), 4 mL of the solution was taken out and passed through a 0.22 μm filter membrane, and then the filtered solution was tested. The filtered rhodamine B solution was placed in a cuvette, and its absorbance was tested by a UV-visible spectrophotometer (λ=501 nm);

[0089] As a control, the catalytic reduction efficiency curve of Congo red was shown in Figure 1. Figure 8 As shown;

[0090] As a control, the irradiation was omitted and the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared in step 3 of Example 1 was used alone. The catalytic reduction efficiency curve of Congo red is shown in FIG. Figure 8 shown.

[0091] Figure 7 The catalytic reduction efficiency curve of naphthalene by the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared by step 3 of Example 1 in Application Example 1 is shown;

[0092] from Figure 7 It can be seen that compared with light alone, the application of catalyst alone has a better degradation effect on naphthalene; and compared with the use of catalyst alone, the application of light on this basis has a significant improvement in the catalytic effect on naphthalene, which shows that 3D-Fe-TCPP-MSNC has a good photocatalytic effect on naphthalene.

[0093] Figure 8 The degradation curve of organic dyes by the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared in step 3 of Example 1 in Application Examples 2 to 3 is shown in FIG. a, which is the catalytic reduction efficiency curve of rhodamine B in Application Example 2, and b, which is the catalytic reduction efficiency curve of Congo red in Application Example 3;

[0094] from Figure 8 It can be seen that the photocatalytic efficiency of 3D-Fe-TCPP-MSNC under light is greatly improved compared with light alone and catalyst alone, indicating that 3D-Fe-TCPP-MSNC has a very ideal catalytic effect on organic dyes Rhodamine B and Congo red.

[0095] Fig. 9 This is a bar graph showing the removal rates of naphthalene, rhodamine B and Congo red using the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst prepared in step 3 of Example 1 in Application Examples 1 to 3.

[0096] from Fig. 9 It can be seen that 3D-Fe-TCPP-MSNC has different degrees of photocatalytic effect on naphthalene, rhodamine B and Congo red, which is universal and has an ideal catalytic effect.

[0097] In summary, the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared by the present invention exhibits a photocatalytic effect on organic pollutants such as polycyclic aromatic hydrocarbons. Compared with light alone, the photocatalyst alone has a higher degradation efficiency for the material, and the photocatalyst has a significantly increased catalytic effect under light conditions, which is more ideal.

Claims

1. A method for preparing an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst, characterized in that The preparation method is specifically completed according to the following steps:

1. Preparation of iron-based porphyrin metal organic framework materials with three-dimensional spatial structure; ①, mix trivalent iron salt, polyvinyl pyrrolidone, trifluoroacetic acid, N,N-dimethylformamide and anhydrous ethanol, and disperse them uniformly by ultrasonication to obtain a precursor solution A; ②, tetrakis(4-carboxyphenyl)porphyrin, N,N-dimethylformamide and anhydrous ethanol were mixed and uniformly dispersed by ultrasonication to obtain a precursor solution B; ③. Precursor solution A and precursor solution B are mixed, dispersed uniformly by ultrasonication, and then transferred into a hydrothermal reactor for hydrothermal reaction at 90°C to 100°C for a period of time, and then centrifuged, washed, dried, and ground to obtain a three-dimensional iron-based porphyrin metal organic framework material; 2. Preparation of highly dispersed artificial humic acid nanocarbon: Artificial humic acid, urea, zinc chloride and potassium chloride are mixed evenly, then placed in a tube furnace and calcined in nitrogen for a period of time, cooled to room temperature, washed with hydrochloric acid and deionized water in sequence, and finally dried and ground to obtain highly dispersed artificial humic acid nanocarbon; 3. Preparation of iron porphyrin@artificial humic acid nanocarbon composite photocatalyst: The three-dimensional iron-based porphyrin metal organic framework material and highly dispersed artificial humic acid nanocarbon are dissolved in N,N-dimethylformamide, stirred evenly, and then transferred into a hydrothermal reactor for hydrothermal reaction at 90°C to 95°C for a period of time, and then centrifuged, washed, and dried to obtain an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst.

2. The method for preparing an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst according to claim 1, characterized in that The ferric iron salt described in step 1① is ferric nitrate nonahydrate; the mass ratio of the ferric iron salt described in step 1① to polyvinyl pyrrolidone is (2-2.1):(5-5.2); the mass volume ratio of the ferric iron salt, trifluoroacetic acid, N,N-dimethylformamide and anhydrous ethanol described in step 1① is (0.0450g-0.0451g):(0.498mL-0.499mL):(112.14mL-112.15mL):(37.38mL-37.39mL).

3. The method for preparing an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst according to claim 1, characterized in that The mass volume ratio of tetrakis (4-carboxyphenyl) porphyrin, N, N-dimethylformamide and anhydrous ethanol described in step 1 ② is (0.055g~0.0551g): (37.38mL~37.39mL): (12.46mL~12.47mL); the time of the hydrothermal reaction described in step 1 ③ is 23h~24h; the volume ratio of the precursor solution A and the precursor solution B described in step 1 ③ is (150~150.02): (49.84~49.86); the solvent used for washing described in step 1 ③ is N, N-dimethylformamide and deionized water; the drying temperature is 60℃~80℃.

4. The method for preparing an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst according to claim 1, characterized in that The mass ratio of the artificial humic acid, urea, zinc chloride and potassium chloride described in step 2 is (4.50g~4.51g):(4.50g~4.51g):(29.91g~29.92g):(15.09g~15.10g); the calcination temperature described in step 2 is 400°C~500°C, and the calcination time is 4h~5h.

5. The method for preparing an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst according to claim 1, characterized in that The preparation method of artificial humic acid described in step 2 is specifically completed according to the following steps: first, washing, drying and crushing the biomass waste to obtain biomass waste powder; dispersing the biomass waste powder and the catalyst in deionized water, and then transferring them to a hydrothermal reactor, and then placing the hydrothermal reactor in an oven for hydrothermal reaction, and then cooling to room temperature to obtain a solid-liquid mixture; filtering the solid-liquid mixture and collecting the liquid; The pH value of the liquid is adjusted to 1 with hydrochloric acid, and the solid is precipitated by standing. The precipitated solid matter is then washed with deionized water to neutrality, dried, and ground into powder to obtain artificial humic acid.

6. The method for preparing the iron porphyrin@artificial humic acid nanocarbon composite photocatalyst according to claim 5, characterized in that The biomass waste is corn stalks; the catalyst is potassium hydroxide; the mass volume ratio of the biomass waste powder, the catalyst and deionized water is 8g:2g:100mL; the temperature of the hydrothermal reaction is 200°C to 250°C, and the time of the hydrothermal reaction is 24h to 30h.

7. The method for preparing an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst according to claim 1, characterized in that The mass ratio of the three-dimensional iron-based porphyrin metal organic framework material and the highly dispersed artificial humic acid nanocarbon described in step three is (2-4):1; the volume ratio of the mass of the three-dimensional iron-based porphyrin metal organic framework material described in step three to N,N-dimethylformamide is (0.2g-0.4g):(130mL-150mL); the time of the hydrothermal reaction described in step three is 23h-24h; the solvent used for washing described in step three is N,N-dimethylformamide and deionized water; the drying temperature is 60°C-80°C.

8. The use of an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst prepared by the preparation method according to claim 1, characterized in that An iron porphyrin@artificial humic acid nanocarbon composite photocatalyst is used to remove organic matter.

9. The use of an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst according to claim 1, characterized in that An iron porphyrin@artificial humic acid nanocarbon composite photocatalyst is used to remove organic matter, which is specifically completed in the following steps: An iron porphyrin@artificial humic acid nano-carbon composite photocatalyst is added to a solution containing organic matter, and a photocatalytic reduction reaction is carried out under light to obtain a solution for removing the organic matter.

10. The use of an iron porphyrin@artificial humic acid nanocarbon composite photocatalyst according to claim 1, characterized in that The organic matter is an organic dye or a polycyclic aromatic hydrocarbon; the organic dye is rhodamine B or Congo red; the polycyclic aromatic hydrocarbon is naphthalene; the dosage of the iron porphyrin@artificial humic acid nano-carbon composite photocatalyst is 0.2g / L to 0.21g / L; the time of the photocatalytic reduction reaction is 10min to 120min; and the light irradiation is xenon lamp light source irradiation.

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