Aluminum-doped hematite, preparation method thereof and application of aluminum-doped hematite in catalyzing peroxide to degrade organic pollutants or remove pathogenic bacteria

Abstract

The invention provides aluminum-doped hematite, a preparation method of the aluminum-doped hematite and application of the aluminum-doped hematite in catalyzing peroxides to degrade organic pollutants or remove pathogenic bacteria. The preparation method of the aluminum-doped hematite comprises the following steps: adding ferric iron salt and aluminum salt into deionized water, reacting, precipitating to separate out a product, washing, drying and grinding to obtain a precursor; calcining the precursor, and then washing and drying to obtain the aluminum-doped hematite. The preparation method is simple, cheap and easily available in raw materials, low in cost, green, safe and environment-friendly; the aluminum element is introduced into the hematite, so that the catalytic activity of the hematite is improved, and the catalytic condition is easy to realize; the aluminum-doped hematite disclosed by the invention has excellent capability of activating peroxide, so that the aluminum-doped hematite shows excellent performance in the aspects of removing environmental organic pollutants and sterilizing.

Description

Technical Field

[0001] The invention relates to aluminum-doped hematite and a preparation method thereof and application thereof in catalyzing peroxide to degrade organic pollutants or remove pathogenic bacteria, belonging to the technical field of functional materials and environmental protection. Background Art

[0002] Pathogens in water remain a major challenge to human health. Waterborne bacterial pathogens can cause diseases such as cholera, hepatitis A, polio, and diarrhea. This not only poses a threat to public health but also hinders economic growth. Although traditional methods such as chlorination and ozone can effectively remove these pathogens, the potential risky byproducts generated during the processing and their high costs are drawbacks of these technologies and their development in practical applications has been limited.

[0003] Environmental pollution is becoming more and more serious with the development of social economy. Especially organic polluted wastewater containing organic matter such as antibiotics. Organic pollutants in wastewater pose a threat to water resources and human health. The most commonly used wastewater treatment technologies are physical, chemical and biological treatment methods. Physical technology mainly includes sedimentation, adsorption and membrane separation. It is difficult to remove these organic pollutants from water using ordinary physical treatment. Conventional chemical methods are also difficult to treat organic pollutants. Biological treatment can solve these problems. However, there are problems such as high investment and operating costs, easy sludge swelling, and long pre-preparation cycle in the biological treatment process.

[0004] Advanced oxidation technology is a modern wastewater treatment technology called Advanced Oxidation Processes (AOPs). This technology deeply oxidizes pollutants such as pathogens and antibiotics in water by producing strong oxidizing species (such as hydroxyl radicals, etc.), converting them into harmless substances, thereby achieving the purpose of purifying water quality. So far, many studies have been conducted to investigate the efficiency of AOPs in treating wastewater containing difficult-to-degrade and toxic pollutants. AOPs are based on hydroxyl radicals, which have a high electrochemical oxidation potential. They have strong oxidizing ability and can easily attack organic functional groups and degrade almost all stubborn organic compounds into carbon dioxide, water and inorganic ions through hydroxylation or dehydrogenation. AOPs are widely used in wastewater treatment to reduce the overall organic content, destroy specific pollutants and sludge treatment. The ability of AOPs to produce hydroxyl radicals further enhances the feasibility of AOPs for the treatment of wastewater containing pollutants such as antibiotics and pathogens.

[0005] However, current advanced oxide materials often require complex preparation methods, and many materials require additional conditions such as ultraviolet light or electricity when used. Among all materials, cobalt-based materials have the highest activity, but cobalt ions are toxic and are greatly restricted in actual use due to ion leaching. Iron-based materials do not have to worry about ion leaching, but their activity is often not ideal. Therefore, it is of great significance to develop a catalytic material with a simple preparation method, high biosafety, high catalytic activity, easy catalytic conditions, and the ability to effectively activate AOPs to achieve excellent sterilization and degradation of organic pollutants. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides an aluminum-doped hematite and a preparation method thereof and an application thereof in catalyzing the degradation of organic pollutants by peroxide or removing pathogenic bacteria. The preparation method of the present invention is simple, the raw materials are cheap and readily available, the cost is low, and the process is green, safe and environmentally friendly; the present invention improves the catalytic activity of the hematite by introducing aluminum into the hematite, and the catalytic conditions are easy to achieve; the aluminum-doped hematite of the present invention has an excellent ability to activate persulfate, thereby showing excellent performance in removing environmental organic pollutants and sterilizing.

[0007] The technical solution of the present invention is as follows:

[0008] A method for preparing aluminum-doped hematite comprises the following steps:

[0009] (1) adding trivalent iron salt and aluminum salt into deionized water, reacting to precipitate a product, and then washing, drying and grinding to obtain a precursor;

[0010] (2) The precursor is calcined, washed and dried to obtain aluminum-doped hematite.

[0011] Preferably according to the present invention, in step (1), the ferric iron salt is ferric nitrate, ferric chloride or ferric sulfate; preferably, the ferric iron salt is ferric nitrate.

[0012] Preferably according to the present invention, in step (1), the aluminum salt is aluminum nitrate, aluminum chloride or aluminum sulfate; preferably, the aluminum salt is aluminum nitrate.

[0013] Preferably, according to the present invention, in step (1), the volume ratio of the molar amount of the ferric salt to the deionized water is 0.05-0.5 mol / L; preferably, the volume ratio of the molar amount of the ferric salt to the deionized water is 0.2-0.3 mol / L.

[0014] Preferably according to the present invention, in step (1), the molar ratio of the aluminum salt to the trivalent iron salt is (0.1-5):100; preferably (0.2-1):100, further preferably (0.2-0.4):100, and most preferably 0.4:100.

[0015] Preferably according to the present invention, in step (1), the reaction temperature is 50-90°C, the reaction time is 0.5-4h, and the reaction is carried out under stirring conditions; preferably, the reaction temperature is 60-80°C, and the reaction time is 0.5-2h; most preferably, the reaction temperature is 60°C, and the reaction time is 1h.

[0016] Preferably, in step (1), the method for precipitating the product is as follows: adding a 1-5 mol / L sodium hydroxide aqueous solution, a sodium carbonate aqueous solution, a potassium hydroxide aqueous solution or a sodium bicarbonate aqueous solution to adjust the pH to 9-12, stirring at room temperature for 1-4 hours, and standing at room temperature for aging for 1-4 hours; preferably, the pH is adjusted to 10-12; most preferably, the pH is adjusted to 10.

[0017] Preferably according to the present invention, in step (2), the calcination time is 2-4 hours; most preferably, the calcination time is 3 hours.

[0018] Preferably according to the present invention, in step (2), the calcination temperature is 300-500°C, and the calcination atmosphere is air; preferably, the calcination temperature is 400-500°C; most preferably, the calcination temperature is 400°C.

[0019] Preferably according to the present invention, in step (2), the heating rate of calcination is 5-10°C / min.

[0020] Aluminum-doped hematite is prepared by the method.

[0021] According to the preferred embodiment of the present invention, in the aluminum-doped hematite, the molar doping amount of aluminum is 0.1-5%. Here, the doping amount refers to the percentage of the molar amount of aluminum to the molar amount of iron.

[0022] The aluminum-doped hematite is used in catalyzing the degradation of organic pollutants by peroxide or in removing pathogenic bacteria by peroxide.

[0023] According to the preferred embodiment of the present invention, the method for catalyzing the degradation of organic pollutants by peroxide is as follows: aluminum-doped hematite is fully dispersed in an aqueous solution of organic pollutants, and then stirred for 10-30 minutes at 25° C. and in the dark to achieve the adsorption-desorption equilibrium of the catalyst; peroxide is added to degrade the organic pollutants at 25° C. Preferably, the concentration of peroxide in the system is 0.1-0.5 mmol / L, and more preferably 0.1 mmol / L.

[0024] Preferably according to the present invention, the organic pollutant is bisphenol A, 4-chlorophenol (4-CP), antibiotic resistance gene or tetracycline.

[0025] According to the present invention, the peroxide is preferably hydrogen persulfate, peroxydisulfate, percarbonate, peracetic acid, hydrogen peroxide, preferably potassium hydrogen persulfate or potassium peroxydisulfate, and more preferably potassium hydrogen persulfate. Potassium hydrogen persulfate has a better effect than potassium peroxydisulfate.

[0026] Preferably according to the present invention, the pathogenic bacteria is Escherichia coli, Staphylococcus aureus or Bacillus subtilis.

[0027] The technical features and beneficial effects of the present invention are as follows:

[0028] 1. The preparation method of the present invention is simple, the raw materials are cheap and easy to obtain, the cost is low, and it is green, safe and environmentally friendly. In the preparation method of the present invention, the molar ratio of the trivalent iron salt and the aluminum salt, the calcination temperature and other conditions are more important. If they are not suitable, the catalytic activity of the hematite will be reduced or even no catalytic activity; in the process of catalyzing the degradation of organic pollutants by peroxide, the concentration of the peroxide needs to be appropriate. If it is not suitable, the reaction activity will also be reduced.

[0029] 2. The present invention improves the catalytic activity of hematite by introducing aluminum into the hematite, and the catalytic conditions are easy to achieve. The aluminum-doped hematite of the present invention has excellent ability to activate peroxides, thereby showing excellent performance in removing environmental organic pollutants and sterilization.

[0030] 3. The aluminum-doped hematite material of the present invention can effectively degrade organic pollutants in water, such as dyes, pesticides and residues in medical wastewater, by activating peroxides to generate strong oxidizing free radicals. Due to the doping of aluminum, the catalytic activity of hematite is greatly improved, so that it exhibits higher degradation efficiency and durability for organic pollutants in complex water environments.

[0031] 4. The aluminum-doped hematite material of the present invention can activate peroxide to produce active oxygen species, which have high sterilization ability, can destroy the cell wall and cell membrane of bacteria, inhibit their growth and eventually lead to bacterial death. This sterilization process does not rely on antibiotics, so it will not produce drug-resistant strains and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a SEM image of aluminum-doped hematite in Example 1 of the present invention.

[0033] Figure 2 This is a TEM image of aluminum-doped hematite in Example 1 of the present invention, wherein the scale size of the left image is 1.0 μm, and the scale size of the right image is 100 nm.

[0034] Figure 3 This is the XRD diagram of aluminum-doped hematite in Example 1 of the present invention.

[0035] Figure 4 The degradation histogram of BPA degradation by aluminum-doped hematite of the present invention is shown in Figure 1. (a) is a degradation histogram of aluminum-doped hematite prepared in Example 1 at different PMS concentrations (PBS concentration in the system), and (b) is a degradation histogram of materials prepared in Examples 1, 20, 21, 22 and Comparative Example 1 at 0.1 mM PMS.

[0036] Figure 5 This is a diagram showing the antibacterial experimental effect of aluminum-doped hematite prepared in Example 1 of the present invention.

[0037] Figure 6 This is a line graph showing the degradation of tetracycline by aluminum-doped hematite prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. Unless otherwise specified, the reagents and raw and auxiliary materials used in the following examples can be obtained from commercial sources.

[0039] Example 1

[0040] A method for preparing aluminum-doped hematite, comprising the steps of:

[0041] S1. Add 100 ml of deionized water, 8.08 g (0.02 mol) of ferric nitrate nonahydrate and 30 mg (0.00008 mol) of aluminum nitrate nonahydrate into a beaker, place in a 60°C constant temperature water bath, and stir magnetically for 1 hour.

[0042] S2. The solution was precipitated by adding 1 mol / L NaOH aqueous solution until the pH of the solution reached 10. After stirring at room temperature for 1 hour and aging at room temperature for 1 hour, the precipitate was centrifuged, and the product was washed three times with water and three times with ethanol, placed in an oven, dried at 105°C, and ground.

[0043] S3. The product was placed in a tube furnace and heated at a rate of 10°C / min, and calcined at 400°C in air atmosphere for 3 hours. After calcination, it was washed with deionized water and ethanol once each and placed in an oven, and dried at 60°C. After drying, aluminum-doped hematite (0.4% Al doped) was obtained.

[0044] In the aluminum-doped hematite material prepared in this embodiment, the molar doping amount of aluminum element is 0.4%.

[0045] The SEM morphology of the aluminum-doped hematite material prepared in this example is as follows: Figure 1 As shown, it is an aggregated granular structure; TEM image is as shown Figure 2As shown in Figure 2, the prepared aluminum-doped hematite particles have a granular structure. Figure 3 , proving that the crystal has a hematite structure.

[0046] The experiment of using aluminum-doped hematite to activate PMS to degrade BPA includes the following steps:

[0047] 60mL of 0.025mM bisphenol A (BPA) aqueous solution was placed in a conical flask, 30mg of aluminum-doped hematite material was added, ultrasonicated for 2min, and then placed in a magnetic stirring constant temperature water bath at 25°C, stirred for 20min in the dark to achieve the adsorption-desorption equilibrium of the catalyst, and then the degradation experiment was carried out. Potassium persulfate (PMS) aqueous solution was added to the above solution, and the reaction was stirred at 25°C in the dark. At fixed time intervals, 2mL of samples were taken for analysis. After the solution was fully mixed with 0.5mL of ethanol, it was immediately filtered with a 0.22μm microporous injection filter membrane. The BPA content was analyzed using HPLC.

[0048] like Figure 4 As shown in (a), after degradation for 1 hour, when the concentration of PMS in the system is 0.1 mM, the prepared material has excellent degradation performance.

[0049] Example 2

[0050] A method for preparing aluminum-doped hematite is as described in Example 1, except that ferric chloride is used instead of ferric nitrate; the other steps and conditions are consistent with those in Example 1.

[0051] Example 3

[0052] A method for preparing aluminum-doped hematite is as described in Example 1, except that iron sulfate is used instead of iron nitrate; the other steps and conditions are consistent with those in Example 1.

[0053] Example 4

[0054] A method for preparing aluminum-doped hematite is as described in Example 1, except that aluminum chloride is used instead of aluminum nitrate; the other steps and conditions are consistent with those in Example 1.

[0055] Example 5

[0056] A method for preparing aluminum-doped hematite is as described in Example 1, except that aluminum sulfate is used instead of aluminum nitrate; the other steps and conditions are consistent with Example 1.

[0057] Example 6

[0058] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S1, the stirring time is 0.5 h; the other steps and conditions are consistent with Example 1.

[0059] Example 7

[0060] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S1, the stirring time is 2 hours; the other steps and conditions are consistent with Example 1.

[0061] Example 8

[0062] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S2, sodium carbonate is used instead of sodium hydroxide; the other steps and conditions are consistent with those in Example 1.

[0063] Example 9

[0064] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S2, potassium hydroxide is used instead of sodium hydroxide; the other steps and conditions are consistent with Example 1.

[0065] Example 10

[0066] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S2, sodium bicarbonate is used instead of sodium hydroxide; the other steps and conditions are consistent with those in Example 1.

[0067] Embodiment 11

[0068] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S3, the heating rate is 5°C / min; the other steps and conditions are consistent with Example 1.

[0069] Example 12

[0070] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S3, the heating rate is 8°C / min; the other steps and conditions are consistent with Example 1.

[0071] Example 13

[0072] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S2, the pH is adjusted to 11; the other steps and conditions are consistent with Example 1.

[0073] Embodiment 14

[0074] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S2, the pH is adjusted to 12; the other steps and conditions are consistent with Example 1.

[0075] Embodiment 15

[0076] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S3, the calcination temperature is 350° C.; the other steps and conditions are consistent with Example 1.

[0077] Example 16

[0078] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S2, the stirring time is 2 hours; the other steps and conditions are consistent with Example 1.

[0079] Embodiment 17

[0080] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S2, the stirring time is 4 hours; the other steps and conditions are consistent with Example 1.

[0081] Embodiment 18

[0082] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S2, the aging time is 2 hours; the other steps and conditions are consistent with Example 1.

[0083] Embodiment 19

[0084] A method for preparing aluminum-doped hematite is as described in Example 1, except that in step S2, the aging time is 4 hours; the other steps and conditions are consistent with Example 1.

[0085] Embodiment 20

[0086] A method for preparing aluminum-doped hematite is as described in Example 1, except that the amount of aluminum nitrate nonahydrate is 0.00004 mol, and the molar ratio of iron ions to aluminum ions is 100:0.2; the other steps and conditions are consistent with Example 1.

[0087] The activity of aluminum-doped hematite was evaluated with BPA as the pollutant. The test method was as described in Example 1, wherein the concentration of PMS in the system was 0.1 mM. The hematite material without aluminum doping (only PMS) and without PMS (only 0.4% Aldoped) were used as controls. The performance of the obtained material (0.2% Al doped) was lower than that of Example 1, as shown in FIG. Figure 4 (b) as shown.

[0088] Embodiment 21

[0089] A method for preparing aluminum-doped hematite is as described in Example 1, except that the amount of aluminum nitrate nonahydrate is 0.00012 mol, and the molar ratio of iron ions to aluminum ions is 100:0.6; the other steps and conditions are consistent with Example 1.

[0090] The activity of aluminum-doped hematite was evaluated with BPA as the pollutant. The test method was as described in Example 1, wherein the concentration of PMS in the system was 0.1 mM. The hematite material without aluminum doping (only PMS) and without PMS (only 0.4% Aldoped) were used as controls. The performance of the obtained material (0.6% Al doped) was lower than that of Example 1, as shown in FIG. Figure 4 (b) as shown.

[0091] Embodiment 22

[0092] A method for preparing aluminum-doped hematite is as described in Example 1, except that the amount of aluminum nitrate nonahydrate is 0.0002 mol, and the molar ratio of iron ions to aluminum ions is 100:1; the other steps and conditions are consistent with Example 1.

[0093] The activity of aluminum-doped hematite was evaluated with BPA as the pollutant. The test method was as described in Example 1, wherein the concentration of PMS in the system was 0.1 mM. The hematite material without aluminum doping (only PMS) and without PMS (only 0.4% Aldoped) were used as controls. The performance of the obtained material (1% Al doped) was lower than that of Example 1, as shown in FIG. Figure 4 (b) as shown.

[0094] Comparative Example 1

[0095] A method for preparing hematite, as described in Example 1, except that aluminum nitrate nonahydrate is not added; other steps and conditions are consistent with Example 1.

[0096] The activity of hematite was evaluated with BPA as the pollutant. The test method was as described in Example 1, wherein the concentration of PMS in the system was 0.1 mM. The hematite material without aluminum doping (only PMS) and without PMS (only 0.4% Al doped) were used as controls. The catalytic performance of the obtained material (0% Al doped) was lower than that of Example 1. Figure 4 (b) as shown.

[0097] Test Example 1

[0098] The sterilization experiment using aluminum-doped hematite included the following steps:

[0099] Staphylococcus aureus, Escherichia coli or Bacillus subtilis (10 μL) were cultured overnight in Luria Bertani (LB) liquid medium, centrifuged and washed several times, and then the bacteria were resuspended in PBS, and the optical density at 600nm was measured using a multi-mode microplate reader (Spark, Tecan), and the OD600 value of the bacterial solution was diluted to 0.1. Subsequently, 100 μL of the diluted bacterial solution and 100 μL of the antibacterial material aqueous dispersion (wherein the concentration of aluminum-doped hematite prepared by the method of Example 1 was 500 mg / L, and the concentration of potassium persulfate (PMS) was 0.1 mM) were added to 800 μL of PBS buffer solution and mixed and cultured for 10 minutes at 37°C. Subsequently, 100 μL of the mixed solution was applied to the solid culture medium, plated for 24 hours, and finally the growth of the bacterial colonies was observed. Each group of experiments was carried out in parallel, and all experiments were repeated three times.

[0100] The antibacterial effect of aluminum-doped hematite is shown in the figure Figure 5 As shown in the figure, it can be seen that the aluminum-doped hematite of the present invention has excellent bactericidal performance, and the bactericidal rate can reach 100%.

[0101] Test Example 2

[0102] 60mL of 0.025mM tetracycline aqueous solution was placed in a conical flask, 30mg of aluminum-doped hematite material prepared by the method of Example 1 was added, ultrasonicated for 2min, then placed in a magnetic stirring constant temperature water bath at 25°C, stirred for 20min under light-proof conditions to achieve adsorption-desorption equilibrium of the catalyst, and then a degradation experiment was performed. Potassium persulfate (PMS) aqueous solution (the concentration of potassium persulfate in the system was 0.1mmol / L) was added to the above solution, and the reaction was stirred at 25°C under light-proof conditions. 2mL of samples were taken for analysis at fixed time intervals. After the solution was fully mixed with 0.5mL of ethanol, it was immediately filtered using a 0.22μm microporous injection filter membrane. The tetracycline content was analyzed using HPLC.

[0103] The experimental effect of aluminum-doped hematite on the degradation of tetracycline is shown in the figure Figure 6 As shown in the figure, it can be seen that the aluminum-doped hematite of the present invention can effectively catalyze PMS to degrade tetracycline, and the degradation rate is above 95%.

[0104] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

[0105] In summary, the preparation method of the aluminum-doped hematite material of the present invention is simple and easy to operate, and the obtained material exhibits excellent performance in pollutant degradation and sterilization, and has broad application prospects.

Claims

1. A method for preparing aluminum-doped hematite, comprising the steps of: (1) adding trivalent iron salt and aluminum salt into deionized water, reacting, precipitating a product, and then washing, drying, and grinding to obtain a precursor; (2) The precursor is calcined, washed and dried to obtain aluminum-doped hematite.

2. The method for preparing aluminum-doped hematite according to claim 1, characterized in that: In step (1), one or more of the following conditions are included: i. The ferric salt is ferric nitrate, ferric chloride or ferric sulfate; preferably, the ferric salt is ferric nitrate; ii. The aluminum salt is aluminum nitrate, aluminum chloride or aluminum sulfate; preferably, the aluminum salt is aluminum nitrate; iii. The molar ratio of the ferric iron salt to the volume ratio of deionized water is 0.05 to 0.5 mol / L; preferably, the molar ratio of the ferric iron salt to the volume ratio of deionized water is 0.2 to 0.3 mol / L.

3. The method for preparing aluminum-doped hematite according to claim 1, characterized in that: In step (1), the molar ratio of the aluminum salt to the trivalent iron salt is (0.1-5):100; preferably (0.2-1):100, more preferably (0.2-0.4):100, and most preferably 0.4:

100.

4. The method for preparing aluminum-doped hematite according to claim 1, characterized in that: In step (1), one or more of the following conditions are included: i. The reaction temperature is 50-90°C, the reaction time is 0.5-4h, and the reaction is carried out under stirring; preferably, the reaction temperature is 60-80°C, and the reaction time is 0.5-2h; most preferably, the reaction temperature is 60°C, and the reaction time is 1h; ii. The method for precipitating the product is as follows: adding a 1-5 mol / L sodium hydroxide aqueous solution, sodium carbonate aqueous solution, potassium hydroxide aqueous solution or sodium bicarbonate aqueous solution to adjust the pH to 9-12, stirring at room temperature for 1-4 hours, and standing at room temperature for aging for 1-4 hours; preferably, the pH is adjusted to 10-12; most preferably, the pH is adjusted to 10.

5. The method for preparing aluminum-doped hematite according to claim 1, characterized in that: In step (2), the calcination temperature is 300-500°C, and the calcination atmosphere is air; preferably, the calcination temperature is 400-500°C; most preferably, the calcination temperature is 400°C.

6. The method for preparing aluminum-doped hematite according to claim 1, characterized in that: In step (2), the calcination time is 2-4 hours; most preferably, the calcination time is 3 hours; and the calcination heating rate is 5-10°C / min.

7. An aluminum-doped hematite prepared by the method according to any one of claims 1 to 6; preferably, the molar doping amount of aluminum in the aluminum-doped hematite is 0.1-5%.

8. Use of the aluminum-doped hematite as claimed in claim 7 in catalyzing the degradation of organic pollutants by peroxide or in catalyzing the removal of pathogenic bacteria by peroxide.

9. The use according to claim 8, characterized in that: The method for catalyzing the degradation of organic pollutants by peroxide is as follows: aluminum-doped hematite is fully dispersed in an aqueous solution of organic pollutants, and then stirred for 10-30 minutes at 25°C in the dark to achieve adsorption-desorption equilibrium of the catalyst; peroxide is added, and the organic pollutants are degraded at 25°C in the dark; preferably, the concentration of peroxide in the system is 0.1-0.5mmol / L, and more preferably 0.1mmol / L.

10. The use according to claim 8, characterized in that: Includes one or more of the following conditions: i. Organic pollutants are bisphenol A, 4-chlorophenol (4-CP), antibiotic resistance genes or tetracycline; ii. The peroxide is hydrogen persulfate, peroxydisulfate, percarbonate, peracetic acid, or hydrogen peroxide, preferably potassium hydrogen persulfate or potassium peroxydisulfate, and more preferably potassium hydrogen persulfate; iii. The pathogenic bacteria are Escherichia coli, Staphylococcus aureus or Bacillus subtilis.

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