A Fe-C microelectrolysis photocatalytic composite catalyst, its preparation method and application

Abstract

The present invention belongs to the technical field of sewage treatment, and particularly relates to an Fe-C microelectrolysis photocatalytic composite catalyst, a preparation method thereof and an application. In the present invention, oxides of main active elements such as platinum, titanium, vanadium, iron, etc. are kneaded with carbon nitride, and an efficient catalyst can be obtained only by simple mixing and calcination. The noble metal platinum has a surface plasmon resonance effect, and the structure of the catalytic material is optimized by changing the electron distribution in the system, which can enhance the absorption and utilization rate of visible light, significantly improve the photocatalytic efficiency of the catalyst, and has the advantages of good stability, strong anti-toxicity ability and environmentally friendly preparation process. The catalyst has broad industrialization prospects and is particularly suitable for catalytic activation of persulfate for advanced oxidation treatment of sewage with a high content of organic matter. The preparation method of the catalyst of the present invention is simple and low in cost, and the prepared catalyst is not only environmentally friendly but also has a long service life.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and particularly relates to an Fe-C microelectrolysis photocatalytic composite catalyst, a preparation method thereof and an application thereof, and is particularly suitable for catalyzing the advanced oxidation of PDS and PMS to treat sewage with a high content of organic substances. Background Art

[0002] With the gradual improvement of the industrialization level, the production volume of industrial organic wastewater, especially pharmaceutical sewage, is increasing. Currently, the commonly used methods for treating organic wastewater mainly include physical method, biological method, chemical method and photocatalytic method. Among them, photocatalytic persulfate (permonosulfate (PMS) or persulfate (PDS)) generates sulfate radicals with high reactivity, which can treat various organic and inorganic sewage. Compared with the Fenton method, it does not produce iron mud and does not require the use of hydrogen peroxide, and has the advantages of low energy consumption, cleanliness and no secondary pollution.

[0003] Although traditional photocatalysts have achieved certain results in sewage treatment and chemical synthesis, they have problems such as narrow light absorption range, high recombination rate of photo-generated electron-hole pairs, low catalytic efficiency and poor stability. In recent years, using metal oxides for catalysis has become one of the efficient and easy-to-operate activation methods. And the level of catalytic performance directly affects the effect of the oxidation technology, so the selection of the catalytic activator becomes the core influencing factor in the persulfate technology.

[0004] Based on this, the present invention proposes a novel photocatalyst with multi-component synergistic effect, aiming to improve the photocatalytic activity and stability and broaden its application range by optimizing the catalyst composition and structure. Summary of the Invention

[0005] The purpose of the present invention is to provide an Fe-C microelectrolysis photocatalytic composite catalyst suitable for various sewage treatment scenarios. By compounding oxides of main active elements such as titanium, vanadium, iron, etc. with graphitic carbon nitride (g-C 3 N 4 ), and simultaneously adding noble metals such as platinum, palladium, rhodium, ruthenium, etc., the applicable range and decontamination ability of the catalyst are further increased. This catalyst has the advantages of high photocatalytic efficiency, good stability, strong anti-toxicity ability and environmentally friendly preparation process, and is particularly suitable for treating sewage with a high content of organic substances.

[0006] Furthermore, the present invention also provides a preparation method of the Fe-C microelectrolysis photocatalytic composite catalyst.

[0007] Furthermore, the present invention also provides an application of the Fe-C microelectrolysis photocatalytic composite catalyst in catalytic degradation of water pollutants.

[0008] Based on the above purposes, the present invention adopts the following technical solutions:

[0009] A method for preparing a Fe-C micro-electrolysis photocatalytic composite catalyst comprises the following steps:

[0010] 1) mixing a certain amount of water-soluble salt of titanium, water-soluble salt of vanadium, water-soluble salt of iron and water-soluble salt of precious metal elements to prepare an aqueous solution of a certain concentration;

[0011] 2) The aqueous solution and graphite carbon nitride (gC 3 N 4 ) and then dehydrated (or not dehydrated) under reduced pressure or normal pressure to obtain a mixture (the purpose of dehydration is to make the mixture viscous and slightly fluid to facilitate catalyst calcination and molding); and then calcined the mixture in a muffle furnace to obtain a block solid;

[0012] 3) The blocky solid obtained in step 2) is crushed and granulated to obtain a photocatalytic composite catalyst with a particle size of 0.1-5 mm.

[0013] Furthermore, the water-soluble titanium salt in step 1) is one or more of titanium tetrachloride, titanium tetraiodide, and titanium tetrabromide. In the final catalyst, titanium exists in the form of titanium dioxide, and its mass accounts for 1 to 30 wt%, preferably 5 to 10 wt%.

[0014] Furthermore, the water-soluble salt of vanadium in step 1) is one or more of metavanadate, pyrovanadate, orthovanadate, polyvanadate, and decavanadate. In the final formed catalyst, vanadium exists in the form of vanadium pentoxide, and its mass proportion is 1 to 15 wt%, preferably 3 to 10 wt%.

[0015] Furthermore, the water-soluble iron salt in step 1) is one or more of ferric chloride, ferric sulfate, and ferric nitrate. In the final catalyst, the iron exists in the form of iron oxide, and its mass accounts for 1 to 30 wt%, preferably 5 to 15 wt%.

[0016] Furthermore, the precious metal described in step 1) is one or more of platinum, palladium, rhodium, and ruthenium, and its water-soluble salts are mainly chlorides, nitrates, etc., and the precious metal content is 0.01 to 3.0 wt% of the total mass of the catalyst, preferably 0.1 to 0.5 wt%.

[0017] Furthermore, in step 1), the concentration of the aqueous solution made of the water-soluble salt of titanium, the water-soluble salt of vanadium, the water-soluble salt of iron or the water-soluble salt of a precious metal element is set to vary from 0.1 to 50 wt% according to the solubility of the material. When the water-soluble salt of titanium, the water-soluble salt of vanadium, the water-soluble salt of iron or the water-soluble salt of a precious metal element is made into an aqueous solution, the aqueous solutions can be prepared separately and then mixed, or the individual water-soluble salts can be mixed and then water can be added to form a mixed solution.

[0018] Further, in step 2), the mass ratio of the aqueous solution to the graphitic carbon nitride is 0.5:1 to 10:1; preferably 1:1 to 3:1.

[0019] Further, the graphitic carbon nitride (g-C 3 N 4 ) in step 2) can be a commercial product or can be prepared by the polymerization of succinic acid and urea or cyanamide, dicyandiamide, or melamine, and dehydrated to a generally viscous and slightly fluid state to facilitate the calcination and molding of the catalyst.

[0020] Further, in step 2), the calcination temperature is 350 to 650 °C, preferably 450 to 550 °C, and the calcination time is 1 to 10 h, preferably 2 to 5 h.

[0021] Further, in step 2), the calcination is carried out in an air environment or an oxygen environment, and the heating rate during calcination is 0.5 to 5 °C / min.

[0022] Further, the calcined product in step 3) is crushed using a ball mill; when granulating, 5 to 10% of the total mass of the crushed solid of sodium silicate or water can be added as a binder.

[0023] Further, the present invention also provides an Fe-C microelectrolysis photocatalytic composite catalyst prepared by the above method, and the photocatalytic composite catalyst can be used as a persulfate activator for the catalytic degradation of organic pollutants or inorganic pollutants in water.

[0024] Further, based on a general inventive concept, the present invention also provides the application of the Fe-C microelectrolysis photocatalytic composite catalyst as a persulfate activator in the catalytic degradation of water pollutants.

[0025] Further, based on a general inventive concept, the present invention also provides the application of the Fe-C microelectrolysis photocatalytic composite catalyst as a persulfate activator in improving the water quality of sewage.

[0026] Further, based on a general inventive concept, the present invention also provides the application of the Fe-C microelectrolysis photocatalytic composite catalyst as a persulfate activator in improving the COD removal rate of sewage.

[0027] Specifically, the persulfate is peroxymonosulfate (PMS) or persulfate (PDS).

[0028] Specifically, the water body is domestic sewage, industrial sewage, agricultural sewage, lake water, river water, or aquaculture water, etc.

[0029] Specifically, the pollutant is one or more of steroid hormone raw materials, organic chemical raw materials, and dyes.

[0030] Specifically, the steroid hormone raw materials include triethylamine, propionic acid, acetone, dihydroxy compound, DMF, n-butanal, isobutyric anhydride, pyridine, dichloromethane, sodium formate, etc.

[0031] Specifically, the organic chemical raw materials include polytetrahydrofuran, chloroacetic acid ethanol, etc.

[0032] Furthermore, when the photocatalytic composite catalyst is used as a persulfate activator to catalytically degrade pollutants in water, it can be reused, and the number of reuse times is 7 times.

[0033] Furthermore, based on a general inventive concept, the present invention also provides a method for catalytically activating persulfate by using the Fe-C microelectrolysis photocatalytic composite catalyst to degrade pollutants in water and improve the COD removal rate of sewage, including the following steps:

[0034] Add an oxidant to the water containing pollutants, then add the photocatalytic composite catalyst, mix evenly, carry out light activation, and then react at room temperature for 1 - 15 h, and the degradation of pollutants below 50000 mg / L in the water can be achieved.

[0035] Specifically, the oxidant is peroxymonosulfate (PMS) or persulfate (PDS).

[0036] Specifically, the mass ratio of water to the photocatalytic composite catalyst is (5 - 15):1, preferably 10:1.

[0037] Specifically, the mass ratio of the oxidant to the photocatalytic composite catalyst is 1:(10 - 15), preferably 1:12.5.

[0038] Specifically, the light is visible light irradiation and / or ultraviolet light irradiation, the wavelength of visible light is 240 nm, and the wavelength of ultraviolet light is 253 nm.

[0039] Furthermore, based on a general inventive concept, the present invention also provides an activation and regeneration method for the Fe-C microelectrolysis photocatalytic composite catalyst, specifically including the following steps:

[0040] For the inactivated or low-activity photocatalytic composite catalyst, first heat it at a rate of 0.5 - 2 °C / min to 120 - 150 °C, keep it warm for 45 - 60 min, then continue to heat it at a rate of 0.5 - 1 °C / min to 350 - 380 °C, keep it warm for 1 - 2 h, and then heat it at a rate of 1 - 2 °C / min to 850 - 950 °C, keep it warm for 1 - 2 h, and then naturally cool it to room temperature to obtain it.

[0041] The Fe-C microelectrolysis photocatalytic composite catalyst prepared by the present invention can be used for catalytic degradation in various sewage treatment scenarios. During the degradation process, visible light and ultraviolet light are used for irradiation activation to catalyze the degradation of sewage by persulfate (PMS) or persulfate (PDS), and it has high catalyst activity.

[0042] Based on photocatalysis, the present invention introduces a variety of active substances to further improve the anti-toxic performance of the catalyst. In particular, the introduction of noble metals enables the catalyst to increase the absorption and utilization of visible light. It has the advantages of high photocatalytic efficiency, good stability, strong anti-toxicity ability, and an environmentally friendly preparation process, and is particularly suitable for the treatment of sewage with a high organic content.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] 1. The present invention kneads the oxides of the main active elements such as platinum, titanium, vanadium, and iron with carbon nitride by a simple method, and an efficient catalyst can be obtained only by simple mixing and calcination. The noble metal platinum has a surface plasmon resonance effect, which optimizes the structure of the catalytic material by changing the electron distribution in the system, enhances the absorption and utilization rate of visible light, significantly improves the photocatalytic efficiency of the catalyst, and has the advantages of good stability, strong anti-toxicity ability, and an environmentally friendly preparation process. When the catalyst is cleaned annually, its single-pass service life can reach more than 5 years, and it can be regenerated more than 3 times. The sewage treatment cost per ton is lower than the currently commonly used sewage treatment processes, and it has broad industrialization prospects. It is particularly suitable for catalytic activation of persulfate for advanced oxidation treatment of sewage with a high organic content.

[0045] 2. The Fe-C microelectrolysis photocatalytic composite catalyst prepared by the present invention can be used for catalytic degradation in various sewage treatment scenarios. During the degradation process, visible light and ultraviolet light are used for irradiation activation to catalyze the degradation of sewage by persulfate (PMS) or persulfate (PDS), and it has high catalyst activity.

[0046] 3. The preparation method of the catalyst described in the present invention is simple and low-cost. The prepared catalyst is not only environmentally friendly but also has a long service life. Detailed Embodiments

[0047] In order to make the technical objectives, technical solutions, and beneficial effects of the present invention clearer, the following further describes the technical solutions of the present invention with specific embodiments. However, the described embodiments are intended to explain the present invention and should not be construed as limiting the present invention. For those not specifying specific techniques or conditions, the techniques or conditions described in the literature in this field or according to the product specifications are followed.

[0048] The raw materials used in the examples are all conventional reagents. The water is deionized water prepared in the laboratory. Graphite phase carbon nitride (g-C 3 N 4 ) is purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0049] Example 1

[0050] This example prepares an Fe-C microelectrolysis photocatalytic composite catalyst containing V, Ti, and Fe elements;

[0051] The preparation method of the Fe-C microelectrolysis photocatalytic composite catalyst includes the following steps:

[0052] Weigh 15.15 g of ferric nitrate, 16.62 g of titanium tetrachloride, and 2.56 g of sodium metavanadate, add them to 90 g of water and stir to completely dissolve. Then add 78 g of graphite phase carbon nitride (g-C 3 N 4 ). After mixing evenly, place it in a muffle furnace, heat it to 550 °C at a rate of 1 °C / min in an air environment, keep it for calcination for 3 h, and then naturally cool it to room temperature to obtain a massive solid;

[0053] Then crush it and add 5% of the total mass of the crushed solid of sodium silicate for granulation, and finally obtain catalyst 1 with a diameter of about 1 mm, denoted as 5% V 2 O 5 / 7% TiO 2 / 10% Fe 2 O 3 -C.

[0054] Example 2

[0055] This example prepares an Fe-C microelectrolysis photocatalytic composite catalyst containing Pt, V, Ti, and Fe elements;

[0056] The preparation method of the Fe-C microelectrolysis photocatalytic composite catalyst includes the following steps:

[0057] Weigh 0.81 g of chloroplatinic acid hexahydrate (platinum content 37 wt%), 15.15 g of ferric nitrate, 16.62 g of titanium tetrachloride, and 2.56 g of sodium metavanadate, add them to 90 g of water and stir to completely dissolve. Then add 78 g of graphite phase carbon nitride (g-C 3 N 4 ). After mixing evenly, place it in a muffle furnace, heat it to 550 °C at a rate of 1 °C / min in an air environment, keep it for calcination for 3 h, and then naturally cool it to room temperature to obtain a massive solid;

[0058] Then crush it and add 5% of the total mass of the crushed solid of sodium silicate for granulation, and finally obtain catalyst 2 with a diameter of about 1 mm, denoted as 0.3% Pt-5% V2 O 5 / 7%TiO 2 / 10%Fe 2 O 3 -C.

[0059] Example 3

[0060] This example prepares a Fe-C micro-electrolysis photocatalytic composite catalyst containing Pt, Ti, and Fe elements;

[0061] The preparation method of the Fe-C micro-electrolysis photocatalytic composite catalyst comprises the following steps:

[0062] Weigh 0.81 g of chloroplatinic acid hexahydrate (platinum content 37 wt%), 15.15 g of ferric nitrate, and 16.62 g of titanium tetrachloride, add them into 90 g of water and stir to completely dissolve them, then add 83 g of graphite carbon nitride (gC 3 N 4 ), after being mixed evenly, placed in a muffle furnace, heated to 550°C at a rate of 1°C / min in an air environment, kept warm and roasted for 3 hours, and then naturally cooled to room temperature to obtain a block solid;

[0063] Then the solid was crushed and granulated with water glass accounting for 5% of the total mass of the crushed solid to obtain catalyst 3 with a diameter of about 1 mm, which was recorded as 0.3% Pt-7% TiO 2 / 10%Fe 2 O 3 -C.

[0064] Performance Test 1

[0065] The catalysts obtained in Examples 1 to 3 were evaluated by taking 1 kg of sewage, adding 8 g of peroxydisulfate (PDS), adding 100 g of catalyst, irradiating with visible light (240 nm) and ultraviolet light (253 nm) for activation, and oxidizing for 15 h. The comparison results are shown in Table 1 below:

[0066] Table 1

[0067]

[0068] It can be concluded from Table 1 that the catalytic system formed by adding a catalyst containing precious metal platinum and peroxydisulfate (PDS) can significantly improve the removal rate of various pollutants, and the addition of vanadium to the catalyst can effectively enhance the synergistic effect with the precious metal. Finally, Example 2 was selected as the optimal preparation process for the catalyst.

[0069] Example 4

[0070] This example prepares a Fe-C micro-electrolysis photocatalytic composite catalyst containing Pd, V, Ti, and Fe elements;

[0071] The preparation method of the Fe-C microelectrolysis photocatalytic composite catalyst comprises the following steps:

[0072] Weigh 0.50 g of palladium chloride (palladium content 59.5 wt%), 15.15 g of iron nitrate, 16.62 g of titanium tetrachloride, and 2.56 g of sodium metavanadate, add them to 90 g of water, stir to dissolve completely, and then add 78 g of graphitic carbon nitride (g-C 3 N 4 ), after mixing evenly, place it in a muffle furnace, heat it to 550 °C at a rate of 1 °C / min in an air environment, keep it for calcination for 3 h, and then cool it naturally to room temperature to obtain a massive solid;

[0073] Then crush it and add 5% of sodium silicate based on the total mass of the crushed solid for granulation to obtain catalyst 4 with a diameter of about 1 mm, denoted as 0.3% Pd-5% V 2 O 5 / 7% TiO 2 / 10% Fe 2 O 3 -C.

[0074] Example 5

[0075] In this example, an Fe-C microelectrolysis photocatalytic composite catalyst containing Ru, V, Ti, and Fe elements is prepared;

[0076] The preparation method of the Fe-C microelectrolysis photocatalytic composite catalyst comprises the following steps:

[0077] Weigh 0.81 g of ruthenium trichloride (ruthenium content 37 wt%), 15.15 g of iron nitrate, 16.62 g of titanium tetrachloride, and 2.56 g of sodium metavanadate, add them to 90 g of water, stir to dissolve completely, and then add 78 g of graphitic carbon nitride (g-C 3 N 4 ), after mixing evenly, place it in a muffle furnace, heat it to 550 °C at a rate of 1 °C / min in an air environment, keep it for calcination for 3 h, and then cool it naturally to room temperature to obtain a massive solid;

[0078] Then crush it and add 5% of sodium silicate based on the total mass of the crushed solid for granulation to obtain catalyst 5 with a diameter of about 1 mm, denoted as 0.3% Ru-5% V 2 O 5 / 7% TiO 2 / 10% Fe 2 O 3 -C.

[0079] Example 6

[0080] This example prepares a Fe-C micro-electrolysis photocatalytic composite catalyst containing Rh, V, Ti, and Fe elements;

[0081] The preparation method of the Fe-C micro-electrolysis photocatalytic composite catalyst comprises the following steps:

[0082] Weigh 1.75 g of sodium hexachlororhodium (rhodium content 17.1 wt%), 15.15 g of ferric nitrate, 16.62 g of titanium tetrachloride, and 2.56 g of sodium pyrovanadate, add them to 90 g of water and stir to completely dissolve them, then add 78 g of graphite carbon nitride (gC 3 N 4 ), after being mixed evenly, placed in a muffle furnace, heated to 550°C at a rate of 1°C / min in an air environment, kept warm and roasted for 3 hours, and then naturally cooled to room temperature to obtain a block solid;

[0083] Then the solid was crushed and granulated with water glass accounting for 5% of the total mass of the crushed solid to obtain catalyst 6 with a diameter of about 1 mm, which was recorded as 0.3% Rh-5% V 2 O 5 / 7%TiO 2 / 10%Fe 2 O 3 -C.

[0084] Performance Test 2

[0085] The catalysts obtained in Examples 4 to 6 were compared with the catalyst in Example 2 under the same conditions using the method in Performance Test 1. The comparison results are summarized in Table 2 below.

[0086] Table 2

[0087]

[0088]

[0089] It can be concluded from Table 2 that the performance of the catalyst prepared using metallic rhodium in Example 6 is substantially equivalent to that of the catalyst prepared using metallic platinum in Example 2. Considering that rhodium is relatively expensive and difficult to recover, the catalyst using metallic platinum in Example 2 is preferred in the present invention.

[0090] Embodiments 7 to 9

[0091] The same preparation method as in Example 2 was used to adjust the content (mass percentage) of precious metal platinum to 0.1%, 0.5%, and 0.7%, respectively, to obtain catalysts of Example 7, Example 8, and Example 9, which were recorded as 0.1%Pt-5%V 2 O 5 / 7%TiO 2 / 10%Fe 2O 3 -C, 0.5% Pt - 5% V 2 O 5 / 7% TiO 2 / 10% Fe 2 O 3 -C, 0.7% Pt - 5% V 2 O 5 / 7% TiO 2 / 10% Fe 2 O 3 -C.

[0092] Performance Test 3

[0093] The catalysts obtained in Examples 7 - 9 and the catalyst in Example 2 were compared under the same conditions using the method in Performance Test 1, and the comparison results were summarized in Table 3 below.

[0094] Table 3

[0095]

[0096]

[0097] It can be concluded from Table 3 that for the prepared catalysts, there is little difference in the effect when the platinum content is above 0.3%. Considering economy, the catalyst with a platinum content of 0.3% is selected as the optimal choice in the present invention.

[0098] Catalyst Application Test

[0099] (I) To prove that the catalyst described in the present invention is applicable to various sewage treatment scenarios, the catalyst in Example 2 was tested for treating different types of sewage generated in multiple projects. Using the method in Performance Test 1, the comparison was carried out under the same conditions, and the comparison results were summarized in Table 4 below. The steroid hormone API in Table 4 is the same as that in Table 1, Table 2, and Table 3.

[0100] Table 4

[0101]

[0102]

[0103] It can be concluded from Table 4 that the catalyst described in the present invention has achieved good results in treating the wastewater generated from polytetrahydrofuran, dodecyl alcohol ester, and chloroacetic acid ethanol by replacing the Fenton method, ordinary micro - electrolysis method, and ozone oxidation method.

[0104] (II) The present invention further evaluated the lifespan and efficiency of the prepared catalyst (the catalyst described in Example 2).

[0105] The specific method is as follows: Raise the COD of the wastewater generated from the steroid hormone API to four times the normal level for feeding, add a catalyst (the catalyst described in Example 2) accounting for 10% (mass fraction) of the wastewater volume, monitor the changes in COD at the inlet and outlet, and when the COD removal rate is lower than 85% of the COD removal rate of the catalyst described in the present invention, adopt the ultrasonic ozone combined cleaning technology to wash off the slime, salts, scale and organic substances adhered to the catalyst.

[0106] If it can only be restored to 90% or less of the performance of the new catalyst, the catalyst needs to be regenerated. The regeneration conditions are as follows: First, raise the temperature to 120°C at a rate of 0.5°C / min and hold for 60 min, then continue to raise the temperature to 350°C at a rate of 1°C / min and hold for 2 h, then raise the temperature to 900°C at a rate of 1°C / min and hold for 2 h, and then naturally cool to room temperature.

[0107] During the test process, the catalyst used (the catalyst described in Example 2) was washed 6 times and regenerated once under this test. The evaluation results are shown in Table 5 below:

[0108] Table 5

[0109] Running time / d COD removal rate in the early stage / % COD removal rate in the later stage / % Catalyst treatment 123 53.87 46.38 Primary washing 118 53.11 46.22 Secondary washing 116 52.79 46.05 Tertiary washing 110 52.32 45.84 Quaternary washing 98 50.20 46.03 Quinary washing 91 49.56 45.96 Sextuple washing 76 47.84 / Septuple washing / regeneration 116 53.03 46.15

[0110] It can be concluded from Table 5 that the performance of the catalyst used (the catalyst described in Example 2) is generally stable. Most of its activity can be restored after 6 washes, but the performance will decline sharply in the later stage of operation. The activity can be restored again to more than 98% through washing and regeneration. Therefore, it can be judged that the service life of this catalyst is relatively long. According to the estimate, it can be used for more than 5 years when washed with a solvent every year, and can be regenerated and used more than 3 times.

[0111] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention as stipulated, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A Fe-C micro-electrolysis photocatalytic composite catalyst, characterized in that: Prepared by the following steps: 1) Mix a certain amount of water-soluble salt of titanium, water-soluble salt of vanadium, water-soluble salt of iron and water-soluble salt of precious metal elements to prepare an aqueous solution of a certain concentration; 2) mixing the aqueous solution in step 1) and graphite phase carbon nitride to obtain a mixture; and then calcining the mixture to obtain a block solid; 3) crushing the blocky solid obtained in step 2) and granulating it to obtain a photocatalytic composite catalyst with a particle size of 0.1-5 mm; Step 1) The water-soluble titanium salt is one or more of titanium tetrachloride, titanium tetraiodide, and titanium tetrabromide. In the final catalyst, titanium exists in the form of titanium dioxide, and its mass proportion is 1 to 30 wt%; Step 1) the water-soluble salt of vanadium is one or more of metavanadate, pyrovanadate, orthovanadate, polyvanadate, and decavanadate, and in the final formed catalyst, vanadium exists in the form of vanadium pentoxide, and its mass proportion is 1 to 15 wt %; Step 1) The water-soluble iron salt is one or more of ferric chloride, ferric sulfate, and ferric nitrate. In the final catalyst, the iron exists in the form of iron oxide, and its mass accounts for 1 to 30 wt %; The noble metal in step 1) is one or more of platinum, palladium, rhodium and ruthenium, and its content is 0.01-3.0 wt % of the total mass of the catalyst, calculated as the noble metal element; In step 2), the mass ratio of the aqueous solution to the graphite phase carbon nitride is 0.5:1 to 10:1; In step 2), the calcination temperature is 350-650°C and the calcination time is 1-10 hours; In step 2), calcination is performed in an air environment or an oxygen environment, and the heating rate during calcination is 0.5 to 5°C / min.

2. The Fe-C micro-electrolysis photocatalytic composite catalyst according to claim 1, characterized in that: In the final formed catalyst, the mass proportion of titanium is 5-10 wt %, the mass proportion of vanadium is 3-10 wt %, the mass proportion of iron is 5-15 wt %, and the content of precious metals is 0.1-0.5 wt % of the total mass of the catalyst.

3. The Fe-C micro-electrolysis photocatalytic composite catalyst according to claim 1, characterized in that: In step 2), the mass ratio of the aqueous solution to the graphite phase carbon nitride is 1:1 to 3:

1.

4. The Fe-C micro-electrolysis photocatalytic composite catalyst according to claim 1, characterized in that: In step 2), the calcination temperature is 450-550° C. and the calcination time is 2-5 hours.

5. Use of the Fe-C micro-electrolysis photocatalytic composite catalyst as a persulfate activator in catalytic degradation of water pollutants according to any one of claims 1 to 4, characterized in that: The persulfate is peroxydisulfate; The pollutants are one or more of steroid hormone APIs, organic chemical raw materials and dyes; The water body is domestic sewage, industrial sewage, agricultural sewage, lake water, river water or aquaculture water; The steroid hormone raw materials include triethylamine, propionic acid, acetone, dihydroxide, DMF, n-butyraldehyde, isobutyric anhydride, pyridine, dichloromethane, and sodium formate; The organic chemical raw materials include polytetrahydrofuran and chloroacetic acid ethanol.

6. The use of the Fe-C micro-electrolysis photocatalytic composite catalyst as a persulfate activator in improving the COD removal rate of sewage according to any one of claims 1 to 4, characterized in that: The persulfate is peroxydisulfate.

7. A method for utilizing the Fe-C micro-electrolysis photocatalytic composite catalyst as claimed in any one of claims 1 to 4 to catalytically activate persulfate to degrade pollutants in water and improve the COD removal rate of sewage, characterized in that: The steps include: Add an oxidant to the water containing pollutants, then add the photocatalytic composite catalyst, mix them evenly, activate them with light, and then react at room temperature for 1 to 15 hours to achieve the degradation of pollutants in the water; The mass ratio of water to the photocatalytic composite catalyst is (5-15):1; the mass ratio of the oxidant to the photocatalytic composite catalyst is 1:(10-15); The oxidizing agent is peroxodisulfate.

8. The method according to claim 7, characterized in that The illumination is visible light illumination and / or ultraviolet light illumination, the wavelength of visible light is 240nm, and the wavelength of ultraviolet light is 253nm.

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