A high-level oxidation process catalyst for treating industrial organic wastewater at low cost and a preparation method and application thereof

Abstract

The application discloses a kind of high oxidation process catalysts for low-cost treatment of industrial organic wastewater and its preparation method and application, belong to environmental remediation material preparation and water pollution control field.The preparation of the catalyst is based on biochar, natural iron manganese mineral, first, after screening, natural magnetite and soft manganese ore are fully mixed in a certain proportion and are subjected to ball milling treatment, and the biochar doped with impurity elements is obtained by pyrolysis method, the impurity element doped biochar, iron manganese mineral composite catalyst is fully mixed, and then ball milling treatment is carried out under the protection of inert atmosphere, and the catalyst is obtained.The impurity element doped biochar contained in the catalyst promotes the aggregation of pollutants and electron transfer, and the iron manganese bimetallic elements can be used as active sites, and the synergistic effect between them significantly increases the activation efficiency and improves the degradation efficiency of pollutants.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of environmental remediation material preparation and water pollution control, and particularly relates to a high-cost treatment of industrial organic wastewater using advanced oxidation process catalyst and its preparation method and application. BACKGROUND

[0002] One of the environmental problems worldwide is the serious water pollution caused by various persistent organic pollutants discharged by industrial activities. Chlorophenol is a kind of persistent organic pollutants, which is widely used as an important organic solvent and intermediate in the production of pesticides, dyes, pharmaceuticals and plastics chemicals, and exists in most chemical industrial wastewater, especially in papermaking and textile industrial wastewater. The stable chlorine atom and aromatic ring in the chemical structure of chlorophenol, combined with the p-π coupling between Cl and benzene ring, makes the C-Cl bond in chlorophenol difficult to activate, resulting in its extremely stable and difficult to biodegrade in the environment, which seriously threatens human health and environmental safety, and has been listed as a priority control pollutant by the United States Environmental Protection Agency and European regulatory agencies.

[0003] In recent decades, different methods have been developed to remove chlorophenols in the environment, which can be divided into three categories: bioremediation technology, physical remediation technology and chemical remediation technology. At present, bioremediation technology and physical remediation technology still have problems such as incomplete removal and insufficient mineralization, so the removal of highly toxic substances is still one of the challenges of current industrial wastewater treatment. Iron-based catalysts catalyzed persulfate advanced oxidation technology has the advantages of strong anti-interference ability, fast reaction rate, etc., and has been widely concerned. However, the synthesis of various high-performance iron-based catalysts has been proved to be complex and expensive, making them economically impractical. And through a large number of literature research, it is found that various synthesized iron-based catalysts have problems such as easy leaching, poor cycle stability, and strict pH limitation. Therefore, it is crucial to study iron-based catalysts with cost-effectiveness, wide adaptability, easy recycling and green environmental protection.

[0004] Many natural iron-containing minerals have been used as inexpensive and readily available iron-based catalysts for the activation of persulfate, avoiding complex preparation processes and controlling solid waste, providing a feasible method for the degradation of chlorophenols. Fe3O4, Fe2O3, FeO(OH), FeS2, FeCO3 in natural iron-containing minerals are the main active ingredients, which can effectively activate persulfate to generate strong oxidizing free radicals to promote the degradation of pollutants. In the process of persulfate activation, Fe(II) structure in natural iron-containing minerals plays an important role. Unlike the activation process of homogeneous Fe 2+ Fe(II) activation of persulfate mainly occurs on the surface of solids, avoiding excessive contact and rapid consumption of Fe(II). However, the Fe(II) content in natural iron-containing minerals is low, and the catalytic performance is weak. SUMMARY

[0005] The application aims to provide a low-cost advanced oxidation process catalyst for treating industrial organic wastewater and a preparation method thereof to overcome the problems of current iron-based catalysts, such as easy leaching, poor cycle stability, complex synthesis process, and high price.

[0006] To achieve the above-mentioned purpose, the application provides the following technical solutions.

[0007] A low-cost advanced oxidation process catalyst for treating industrial organic wastewater is prepared by a method comprising the following steps:

[0008] (1) The natural iron ore and natural manganese ore particles are ground and then preliminarily screened through a 20-mesh sieve, respectively;

[0009] (2) The sieved iron ore particles and manganese ore particles obtained in step (1) are added to a ball mill for ball milling treatment under inert gas protection to obtain iron ore powder and manganese ore powder after ball milling;

[0010] (3) The iron ore powder and manganese ore powder after ball milling obtained in step (2) are mixed in a certain proportion and then added to a ball mill for ball milling treatment again to obtain a micron-sized iron-manganese bimetallic composite mineral catalyst;

[0011] (4) Biomass is soaked in a solution containing a heteroelement reagent, and the soaked biomass is dried and then placed in a tube furnace for pyrolysis under inert gas atmosphere at a certain temperature for a certain time to obtain a heteroelement-doped biochar;

[0012] (5) The micron-sized iron-manganese bimetallic composite mineral catalyst obtained in step (3) is mixed with the heteroelement-doped biochar obtained in step (4) and ball milled under inert gas to obtain a heteroelement-doped biochar-loaded micron-sized iron-manganese bimetallic composite mineral catalyst.

[0013] In step (1) of the above method, the natural iron ore can be at least one of magnetite (active component Fe3O4, containing impurity elements such as vanadium (V), chromium (Cr), manganese (Mn), magnesium (Mg), zinc (Zn), and aluminum (Al), and the content of magnetic iron reaches 25.29%), hematite, siderite, ilmenite, pyrite, limonite, and iron spinel; and the manganese ore can be at least one of pyrolusite (active component MnO2, also containing impurities such as Fe2O3, MgO, Al2O3, CaO, and SiO2, and the content of manganese reaches 21.63%), hard manganese ore, hydro manganite, brown manganese ore, black manganese ore, rhodochrosite, and manganese spinel.

[0014] The grinding body used in the ball milling treatment in steps (2) and (3) is a zirconia ball, and the weight ratio of the zirconia ball to the mineral is 30-60:1, and specifically can be 45:1;

[0015] Preferably, in steps (2) and (3), the inert gas used in the ball milling treatment is N2 or Ar, the purging time is 15-45 min, specifically can be 30 min, the ball milling speed is 200-600 rpm, specifically can be 400 rpm, and the ball milling time is 8-16 h, specifically can be 12 h.

[0016] Preferably, in step (2), the particle size of the iron ore powder and the manganese ore powder after ball milling is in the range of 0-8 μm, and the endpoint 0 is not desirable.

[0017] Preferably, in step (3), the mixing ratio (mass ratio) of the iron ore powder and the manganese ore powder is 3:1-1:3, and specifically can be 3:1, 2:1, 1:1, 1:2, and 1:3.

[0018] Preferably, in step (3), the particle size of the micron-sized iron-manganese double-metal composite mineral catalyst is in the range of 0-3.5 μm, and the endpoint 0 is not desirable.

[0019] In step (4), the hetero-element can be at least one of nitrogen, phosphorus, and sulfur elements; and the solution containing the hetero-element reagent can be a solution of at least one compound or a complex solution of multiple compounds selected from urea, phosphoric acid, phytic acid, and thiourea.

[0020] The biomass can be at least one of waste wood, straw, rice husk, and coconut shell.

[0021] Preferably, the hetero-element reagent is urea, and the biomass is straw.

[0022] The mass ratio of urea to straw is 3:1-1:3, and specifically can be 3:1, 2:1, 1:1, 1:2, and 1:3, and more specifically can be 1:2.

[0023] The soaking time can be 8-16 h, and specifically can be 12 h.

[0024] The drying time is 12-14 h, and specifically can be 12 h.

[0025] The inert gas used in the calcination process of the tubular furnace is N2, the calcination time is 2-6 h, specifically can be 4 h, and the temperature is 600-1200℃, specifically can be 600℃.

[0026] Preferably, in step (5), the mass ratio of the hetero-element-doped biochar to the micron-sized iron-manganese double-metal composite mineral catalyst can be 3:1-1:3, and specifically can be 3:1, 2:1, 1:1, 1:2, or 1:3.

[0027] The grinding body used in the ball milling is a zirconium oxide ball, and the weight ratio of the zirconium oxide ball to the mixture is 30-60:1, and specifically can be 45:1.

[0028] The inert gas used in the ball milling is N2 or Ar, and specifically can be N2, the purging is 15-45 min, and specifically can be 30 min, the ball milling speed is 200-600 rpm, and specifically can be 400 rpm, and the ball milling time is 8-16 h, and specifically can be 12 h.

[0029] The hetero-element-doped biochar-supported micron-sized iron-manganese bimetallic composite mineral catalyst prepared by the above method also belongs to the protection scope of the present application.

[0030] The application of the above hetero-element-doped biochar-supported micron-sized iron-manganese bimetallic composite mineral catalyst in the advanced oxidation treatment of industrial organic wastewater also belongs to the protection scope of the present application.

[0031] In the application, the hetero-element-doped biochar-supported micron-sized iron-manganese bimetallic composite mineral catalyst is used to activate persulfate to degrade chlorophenol organic pollutants in industrial organic wastewater.

[0032] In the application, the persulfate can be monopersulfate (hydrogen ammonium persulfate, hydrogen potassium persulfate, and hydrogen sodium persulfate) and dipersulfate (ammonium persulfate, potassium persulfate, and sodium persulfate).

[0033] The chlorophenol organic pollutants include 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol.

[0034] The dosage of the hetero-element-doped biochar-supported micron-sized iron-manganese bimetallic composite mineral catalyst is 0.5-3 g / L, the concentration of the persulfate is 3-15 mM, and the initial concentration of the chlorophenol organic pollutants in the chlorophenol organic wastewater is 1-20 mg / L.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] (1) The present application uses natural minerals and waste biomass that are widely present in nature and easy to obtain as a substrate to prepare a low-cost and high-efficiency catalyst, which not only has significant cost-effectiveness, but also plays a role in controlling solid waste and promoting sustainable use of resources, and has certain theoretical and practical significance.

[0037] (2) The natural iron ore used in the present application can stably accommodate the existence of Fe(II) and Fe(III), and has a higher catalytic activity than homogeneous Fe 2+The activation process is different, and the activation of the structure Fe(II) to persulfate mainly occurs on the mineral surface, avoiding excessive contact and rapid consumption of Fe(II), and greatly improving the catalytic efficiency.

[0038] (3) The micron-sized iron-manganese double-metal composite mineral catalyst is constructed by introducing natural manganese ore in the application, Fe(II), Mn(II) and Mn(III) can all act as electron donors to activate persulfate, and the rapid oxidation-reduction cycle between them can realize the continuous replenishment of the catalytic active site, promoting the activation of persulfate and the degradation of pollutants.

[0039] (4) The strong-conductivity biochar loaded iron-manganese double-metal mineral catalyst is constructed by introducing hetero-element doped biochar in the application, which promotes the adsorption capacity and removal efficiency of the composite material to pollutants, and enhances the electron transfer of Fe(II), Mn(II) and Mn(III) to persulfate and the degradation of pollutants.

[0040] (5) The catalyst prepared in the application has excellent stability and reusability, overcoming the problems of easy dissolution and poor cycle stability of traditional iron-based catalysts. The degradation rate of pollutants is still more than 90% after five cycles, and it has significant catalytic activity. In addition, the catalyst shows excellent degradation effect on various organic pollutants, showing its wide application prospect in the field of industrial organic wastewater treatment.

[0041] (6) The catalyst is prepared by ball milling and pyrolysis treatment in the application, and the preparation process is simple, convenient to operate and suitable for large-scale application. The iron ore size is reduced by ball milling process to enhance the exposure of active ingredients, and the catalytic performance of the catalyst is optimized by introducing natural manganese ore to construct iron-manganese double-metal composite minerals to fully play the synergistic effect of iron-manganese double-metal, and the removal rate of pollutants and the electron transfer rate of the composite material are further promoted by using waste biomass pyrolysis to obtain strong-conductivity biochar, and the mineralization capacity of pollutants is improved, which can realize efficient treatment of industrial organic wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 SEM image of nitrogen-doped biochar loaded micron-sized iron-manganese mineral composite catalyst.

[0043] Figure 2 EDS spectrum of nitrogen-doped biochar loaded micron-sized iron-manganese mineral composite catalyst.

[0044] Figure 3 XRD pattern of nitrogen-doped biochar loaded micron-sized iron-manganese mineral composite catalyst.

[0045] Figure 4Hysteresis loop of the micron-sized iron-manganese mineral composite catalyst supported on nitrogen-doped biochar.

[0046] Figure 5 Biological toxicity evaluation results of the degradation intermediates on fish.

[0047] Figure 6 Biological toxicity evaluation results of the degradation intermediates on fish.

[0048] Figure 7 Biological toxicity evaluation results of the degradation intermediates on fish.

[0049] Figure 8 Biological toxicity evaluation results of the degradation intermediates on fish. DETAILED DESCRIPTION

[0050] The application will be further described in conjunction with the specific embodiments. The examples given are only to illustrate the application, and are not intended to limit the scope of the application. The examples provided below can serve as a guide for further improvement by those skilled in the art, and do not constitute any limitation on the application.

[0051] The experimental methods in the following examples are all conventional methods, and are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions, unless otherwise specified. The materials, reagents, etc. used in the following examples can be obtained commercially, unless otherwise specified.

[0052] Example 1

[0053] (1) Under N2 atmosphere, the natural magnetite particles and natural pyrolusite particles ground through a 20-mesh sieve were added into a zirconia jar for ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of mineral to zirconia ball 1:45), to obtain micron-sized magnetite powder (0-8 μm, endpoint 0 not acceptable) and manganese mineral powder (0-8 μm, endpoint 0 not acceptable). The obtained magnetite powder and pyrolusite powder were thoroughly mixed according to a mass ratio of 3:1, and were added into a zirconia jar for ball milling treatment again for 12 h (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia ball to mineral 45:1), to obtain micron-sized iron-manganese composite mineral catalyst (0-3.5 μm, endpoint 0 not acceptable) with a mass ratio of magnetite:pyrolusite of 3:1.

[0054] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant for catalytic degradation performance testing. The degradation experiment was carried out in a 150 mL brown serum vial, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min) and separate the catalyst material using magnetic separation technology. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatography instrument (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times. The chromatographic column is a C18 column with a specification of 4.6 x 250 mm, 5 μm, and the column temperature is maintained at 30°C.

[0055] Example 2

[0056] Compared with Example 1, the difference lies in the different synthesis ratios.

[0057] (1) Under N2 atmosphere, natural magnetite particles and natural soft manganese ore particles passed through a 20-mesh sieve were added to a zirconia jar for ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of mineral addition to zirconia ball 1:45). Magnetite powder (0-8 μm, endpoint 0 not available) and soft manganese ore powder (0-8 μm, endpoint 0 not available) were obtained after ball milling. The obtained magnetite powder and soft manganese ore powder were thoroughly mixed in a mass ratio of 2:1 and added to a zirconia jar for further ball milling treatment for 12 h (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia ball to mineral 45:1). A micron-sized iron-manganese composite mineral catalyst with a mass ratio of magnetite to soft manganese ore of 2:1 was obtained (particle size 0-3.5 μm, endpoint 0 not available).

[0058] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant for catalytic degradation performance testing. The degradation experiment was carried out in a 150 mL brown serum bottle, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min) and separate the catalyst material using magnetic separation technology. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatography instrument (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times. The chromatographic column is a C18 column with a specification of 4.6 x 250 mm, 5 μm, and the column temperature is maintained at 30°C.

[0059] Example 3

[0060] Compared with Example 1, the difference lies in the different synthesis ratios.

[0061] (1) Under N2 atmosphere, natural magnetite particles and natural soft manganese ore particles passed through a 20-mesh sieve were added to a zirconia jar for ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of mineral addition to zirconia ball 1:45). Magnetite powder (0-8 μm, endpoint 0 not available) and soft manganese ore powder (0-8 μm, endpoint 0 not available) were obtained after ball milling. The obtained magnetite powder and manganese ore powder were thoroughly mixed in a mass ratio of 1:1 and added to a zirconia jar for further ball milling treatment for 12 h (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia ball to mineral 45:1). A micron-sized iron-manganese composite mineral catalyst (particle size 0-3.5 μm, endpoint 0 not available) with a mass ratio of magnetite to soft manganese ore of 1:1 was obtained.

[0062] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant for catalytic degradation performance testing. The degradation experiment was carried out in a 150 mL brown serum bottle, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min) and separate the catalyst material using magnetic separation technology. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatography instrument (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times. The chromatographic column is a C18 column with a specification of 4.6 x 250 mm, 5 μm, and the column temperature is maintained at 30°C.

[0063] Example 4

[0064] Compared with Example 1, the difference lies in the different synthesis ratios.

[0065] (1) Under N2 atmosphere, natural magnetite particles and natural soft manganese ore particles passed through a 20-mesh sieve were added to a zirconia jar for ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia balls to minerals 1:45), to obtain ball-milled magnetite powder (0-8 μm, endpoint 0 not available) and soft manganese ore powder (0-8 μm, endpoint 0 not available). The obtained magnetite powder and manganese ore powder were thoroughly mixed in a mass ratio of 1:2 and added to a zirconia jar for further ball milling treatment for 12 h (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of mineral addition to zirconia balls 45:1), to obtain micron-sized iron-manganese composite mineral catalyst (particle size 0-3.5 μm, endpoint 0 not available) with a mass ratio of magnetite to soft manganese ore of 1:2.

[0066] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant for catalytic degradation performance testing. The degradation experiment was carried out in a 150 mL brown serum bottle, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min) and separate the catalyst material using magnetic separation technology. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatography instrument (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times. The chromatographic column is a C18 column with a specification of 4.6 x 250 mm, 5 μm, and the column temperature is maintained at 30°C.

[0067] Example 5

[0068] Compared with Example 1, the difference lies in the different synthesis ratios.

[0069] (1) Under N2 atmosphere, natural magnetite particles and natural soft manganese ore particles passed through a 20-mesh sieve were added to a zirconia jar for ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of mineral addition to zirconia ball 1:45). Magnetite powder (0-8 μm, endpoint 0 not available) and soft manganese ore powder (0-8 μm, endpoint 0 not available) were obtained after ball milling. The obtained magnetite powder and manganese ore powder were thoroughly mixed in a mass ratio of 1:3 and added to a zirconia jar for further ball milling treatment for 12 h (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia ball to mineral 45:1). A micron-sized iron-manganese composite mineral catalyst (particle size 0-3.5 μm, endpoint 0 not available) with a mass ratio of magnetite to soft manganese ore of 1:3 was obtained.

[0070] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant for catalytic degradation performance test, and the degradation experiment is carried out in a 150 mL brown serum bottle with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min), and separate the catalyst material using magnetic separation technology. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatography instrument (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times, and the chromatographic column is a C18 column with a size of 4.6 x 250 mm, 5 μm, and the column temperature is maintained at 30°C.

[0071] The degradation rate and reaction rate constant of Examples 1-5 are shown in Table 1 below:

[0072] Table 1

[0073]

[0074] As can be seen from Table 1, the ratio of magnetite to pyrolusite has a significant effect on the catalytic performance of the obtained catalyst, and the catalyst prepared by mixing magnetite and pyrolusite at a mass ratio of 1:1 and ball milling has the best catalytic activity.

[0075] Example 6

[0076] Compared with Example 3, the difference lies in the different synthetic ingredients.

[0077] (1) Weigh 5 g of urea and dissolve it in deionized water, and then immerse 10 g of corn straw powder in it for 12 h, and then dry it in an oven for 12 h; after drying, place it in a tube furnace and calcine it under N2 atmosphere for 4 h at a temperature of 600°C to obtain nitrogen-doped biochar.

[0078] (2) The nitrogen-doped biochar and the optimal ratio of iron-manganese composite mineral catalyst prepared in Example 3 were mixed in a mass ratio of 3:1 under a N2 atmosphere and added to a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia balls to mixture 45:1), to obtain a nitrogen-doped biochar supported micron-sized iron-manganese composite mineral catalyst with a mass ratio of nitrogen-doped biochar: magnetite: soft manganese ore of 3:1:1.

[0079] The prepared nitrogen-doped biochar supported micron-sized iron-manganese composite mineral catalyst was subjected to a series of characterizations to evaluate the catalytic performance of the catalyst. The SEM characterization results are shown in FIG. 6, the EDS energy spectrum analysis results are shown in FIG. 7, the XRD characterization results are shown in FIG. 8, and the hysteresis loop characterization results are shown in FIG. 9. Figure 1 Figure 2 Figure 3 Figure 4

[0080] (3) 2,4,6-trichlorophenol was selected as the characteristic pollutant for catalytic degradation performance testing. The degradation experiment was carried out in a 150 mL brown serum bottle with a butyl rubber plug seal. The specific steps are as follows: first, 0.25 g of catalyst (2.5 g / L, vacuum sealed) was weighed and dispersed into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Subsequently, 0.27 g of ammonium persulfate (12 mM) was added to initiate the reaction and the serum bottle was sealed. The above serum bottle was placed in a constant temperature shaking incubator at 25°C and the experiment was carried out at a rotation speed of 180 r / min. Samples were taken from the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min) and the catalyst material was separated using magnetic separation technology. Subsequently, 1.2 mL of supernatant was collected, filtered using a 0.22 μm PTFE membrane, and placed in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. The concentration of 2,4,6-trichlorophenol in the solution at different times was determined using a high-performance liquid chromatography instrument (HPLC). The chromatographic column was a C18 column with a specification of 4.6 x 250 mm, 5 μm, and the column temperature was maintained at 30°C.

[0081] Example 7

[0082] Compared with Example 6, the difference lies in the different synthesis ratio.

[0083] ​​​​(1) The nitrogen-doped biochar prepared in Example 6 and the optimal proportion of iron-manganese mineral composite catalyst prepared in Example 3 were mixed in a mass ratio of 2:1 under N2 atmosphere and added into a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia balls to mixture 45:1), to obtain a nitrogen-doped biochar supported micron-sized iron-manganese composite mineral catalyst with a mass ratio of nitrogen-doped biochar:magnetite:pyrolusite of 2:1:1.

[0084] (2) 2,4,6-trichlorophenol was selected as the characteristic pollutant for the catalytic degradation performance test. The degradation experiment was carried out in a 150 mL brown serum bottle with a butyl rubber plug. The specific steps are as follows: first, 0.25 g of catalyst (2.5 g / L, vacuum sealed) was weighed and dispersed into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, 0.27 g of ammonium persulfate (12 mM) was added to start the reaction and the serum bottle was sealed. The above serum bottle was placed in a constant temperature shaking incubator at 25°C and the experiment was carried out at a speed of 180 r / min. Samples were taken from the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min) and the catalyst material was separated using magnetic separation technology. Then, 1.2 mL of supernatant was collected, filtered with a 0.22 μm PTFE membrane, and the filtered sample was placed in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. The concentration of 2,4,6-trichlorophenol in the solution at different times was determined using a high performance liquid chromatography instrument (HPLC). The chromatographic column was a C18 column with a size of 4.6x250 mm and a particle size of 5 μm, and the column temperature was maintained at 30°C.

[0085] Example 8

[0086] Compared with Example 6, the difference lies in the different synthesis ratio.

[0087] (1) The nitrogen-doped biochar prepared in Example 6 and the optimal proportion of iron-manganese mineral composite catalyst prepared in Example 3 were mixed in a mass ratio of 2:1 under N2 atmosphere and added into a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia balls to mixture 45:1), to obtain a nitrogen-doped biochar supported micron-sized iron-manganese composite mineral catalyst with a mass ratio of nitrogen-doped biochar:magnetite:pyrolusite of 2:1:1.

[0088] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant for catalytic degradation performance testing. The degradation experiment was carried out in a 150 mL brown serum vial, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min), and use magnetic separation technology to separate the catalyst material. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatograph (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times. The chromatographic column is a C18 column with a specification of 4.6 x 250 mm, 5 μm, and the column temperature is maintained at 30°C.

[0089] Example 9

[0090] Compared with Example 6, the difference lies in the different synthesis ratios.

[0091] (1) Under N2 atmosphere, the nitrogen-doped biochar prepared in Example 6 and the optimal ratio of iron-manganese composite mineral catalyst prepared in Example 3 were mixed in a mass ratio of 1:2 and added into a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia balls to mixture 45:1), to obtain a nitrogen-doped biochar supported micron-sized iron-manganese composite mineral catalyst with a mass ratio of nitrogen-doped biochar:magnetite:soft manganese ore of 1:2:2.

[0092] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant for catalytic degradation performance testing. The degradation experiment was carried out in a 150 mL brown serum vial, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min), and use magnetic separation technology to separate the catalyst material. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatograph (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times. The chromatographic column is a C18 column with a specification of 4.6 x 250 mm, 5 μm, and the column temperature is maintained at 30°C.

[0093] Example 10

[0094] Compared with Example 6, the difference lies in the different synthesis ratios.

[0095] (1) Under N2 atmosphere, the nitrogen-doped biochar prepared in Example 6 and the optimal ratio of iron-manganese composite mineral catalyst prepared in Example 3 were mixed in a mass ratio of 1:3 and added into a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia balls to mixture 45:1), to obtain a nitrogen-doped biochar supported micron-sized iron-manganese composite mineral catalyst with a mass ratio of nitrogen-doped biochar:magnetite:soft manganese ore of 1:3:3.

[0096] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant for catalytic degradation performance testing. The degradation experiment was carried out in a 150 mL brown serum bottle, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min) and separate the catalyst material using magnetic separation technology. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatography instrument (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times. The chromatographic column is a C18 column with a specification of 4.6 x 250 mm, 5 μm, and the column temperature is maintained at 30°C.

[0097] Comparative Example 1

[0098] Compared with Examples 6-10, the difference lies in the different synthetic components of the biochar.

[0099] (1) Weigh 10 g of corn straw powder and place it in a tube furnace for calcination under N2 atmosphere for 4 h at a temperature of 600°C to obtain biochar without doping with impurity elements.

[0100] (2) Mix the biochar prepared above and the optimal ratio of iron-manganese composite mineral catalyst prepared in Example 3 according to a mass ratio of 3:1, and add them to a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia balls to mixture 45:1) to obtain a biochar-loaded micron-sized iron-manganese composite mineral catalyst with a biochar:magnetite:soft manganese ore mass ratio of 3:1:1.

[0101] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant to test the catalytic degradation performance. The degradation experiment was carried out in a 150 mL brown serum bottle, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. At specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min), sample the reaction mixture and separate the catalyst material using magnetic separation technology. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatography instrument (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times. The chromatographic column is a C18 column with a size of 4.6 x 250 mm and a particle size of 5 μm. The column temperature is maintained at 30°C.

[0102] The removal rates and reaction rate constants of Examples 6-10 and Comparative Example 1 are shown in Table 2 below:

[0103] Table 2

[0104]

[0105] As can be seen from Table 2, the addition of biochar as a carrier has a significant effect on the catalytic performance of the resulting catalyst, and the catalyst prepared using nitrogen-doped biochar as a carrier has higher catalytic activity. Among them, the catalyst prepared by mixing and ball milling the nitrogen-doped biochar, magnetite, and pyrolusite in a mass ratio of 3:1 has the highest catalytic activity.

[0106] Example 11

[0107] Compared with Example 10, the difference lies in testing the practical application of the catalyst using different pollutants.

[0108] (1) Under N2 atmosphere, the nitrogen-doped biochar prepared in Example 6 and the optimal ratio of iron-manganese mineral composite catalyst prepared in Example 3 were mixed in a mass ratio of 3:1 and added into a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia balls to mixture 45:1), to obtain a nitrogen-doped biochar-supported micron-sized iron-manganese composite mineral catalyst with a nitrogen-doped biochar:magnetite:pyrolusite mass ratio of 3:1:1.

[0109] (2) Chloramphenicol, triclosan and bisphenol A were selected as representative organic pollutants to evaluate the removal ability of the catalysts for different pollutants. The degradation experiments were carried out in 150 mL brown serum vials, which were sealed with butyl rubber stoppers. The specific steps were as follows: first, 0.25 g of catalyst (2.5 g / L, vacuum sealed) was weighed and dispersed into 100 mL of chloramphenicol, triclosan and bisphenol A aqueous solution (10 mg / L), respectively. Subsequently, 0.27 g of ammonium persulfate (12 mM) was added to initiate the reaction and the serum vials were sealed. The above serum vials were placed in a constant temperature incubator at 25°C and the experiment was carried out at a rotation speed of 180 r / min. Samples were taken from the reaction mixture at specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min) and the catalyst material was separated using magnetic separation technology. Subsequently, 1.2 mL of supernatant was collected and filtered using a 0.22 μm PTFE membrane. The filtered sample was placed in a liquid chromatography sample bottle containing 50 μL of methanol for timely quenching, and the concentrations of chloramphenicol, triclosan and bisphenol A in the solution at different times were determined using a high performance liquid chromatography instrument (HPLC). The chromatographic column was a C18 column with a specification of 4.6 x 250 mm, 5 μm, and the column temperature was maintained at 30°C. The degradation results are shown in Table 3:

[0110] Table 3

[0111]

[0112] Example 12

[0113] Compared with Example 10, the difference lies in that the recyclability of the catalyst is tested by a cycle test.

[0114] (1) The nitrogen-doped biochar prepared in Example 6 and the optimal ratio of iron-manganese mineral composite catalyst prepared in Example 3 were mixed in a mass ratio of 3:1 under N2 atmosphere and added into a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia balls to mixture 45:1), to obtain a nitrogen-doped biochar supported micron-sized iron-manganese composite mineral catalyst with a mass ratio of nitrogen-doped biochar:magnetite:soft manganese ore of 3:1:1.

[0115] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant to test the catalytic degradation performance. The degradation experiment was carried out in a 150 mL brown serum bottle, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. At specific times (0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min), sample the reaction mixture and separate the catalyst material using magnetic separation technology. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography sample bottle containing 50 μL of methanol for immediate quenching. Use a high-performance liquid chromatography instrument (HPLC) to determine the concentration of 2,4,6-trichlorophenol in the solution at different times. The chromatographic column is a C18 column with a size of 4.6 x 250 mm and a particle size of 5 μm, and the column temperature is maintained at 30°C. After each round of catalytic experiment, the catalyst is collected by magnetic separation and washed with deionized water and ethanol for 3 times to remove surface impurities. Dry the collected catalyst in a freeze dryer for 12 h. Repeat the cycle test for 5 times to evaluate the stability of the catalyst in activating persulfate to degrade 2,4,6-trichlorophenol. The degradation results are shown in Table 4:

[0116] Table 4

[0117]

[0118] Example 13

[0119] Compared with Example 10, the difference is that the TOC removal rate in the catalytic reaction system is tested to evaluate the mineralization ability of the nitrogen-doped biochar loaded iron-manganese mineral composite catalyst activated by the persulfate system to 2,4,6-trichlorophenol.

[0120] (1) Under N2 atmosphere, the nitrogen-doped biochar prepared in Example 6 and the optimal ratio of iron-manganese mineral composite catalyst prepared in Example 3 are mixed in a mass ratio of 3:1 and added into a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia ball to mixture 45:1), to obtain a nitrogen-doped biochar loaded micron-sized iron-manganese composite mineral catalyst with a mass ratio of nitrogen-doped biochar:magnetite:soft manganese ore of 3:1:1.

[0121] (2) Select 2,4,6-trichlorophenol as the characteristic pollutant to test the catalytic degradation performance. The degradation experiment was carried out in a 150 mL brown serum bottle, and the bottle opening was sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 20 min, 40 min, 60 min) and separate the catalyst material using magnetic separation technology. Then, collect 15 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a centrifuge tube containing 50 μL of methanol for timely quenching. Measure the TOC content in the system using a total organic carbon analyzer (Sievers M9). The mineralization results are shown in Table 5.

[0122] Table 5

[0123]

[0124] Example 14

[0125] Compared with Example 10, the difference lies in the identification and identification of the intermediates produced by 2,4,6-trichlorophenol during the catalytic reaction process, and the toxicity of the intermediate products is analyzed to evaluate the safety of the nitrogen-doped biochar loaded iron-manganese mineral composite catalyst for repairing organic contaminated wastewater.

[0126] (1) Under N2 atmosphere, the nitrogen-doped biochar prepared in Example 6 and the optimal ratio of iron-manganese mineral composite catalyst prepared in Example 3 were mixed in a mass ratio of 3:1 and added into a zirconia jar for 12 h of ball milling treatment (ball milling speed 400 rpm, ball milling time 12 h, weight ratio of zirconia ball to mixture 45:1), to obtain a nitrogen-doped biochar loaded micron-sized iron-manganese composite mineral catalyst with a mass ratio of nitrogen-doped biochar:magnetite:soft manganese ore of 3:1:1.

[0127] (2) Select 2,4,6-trichlorophenol as a characteristic pollutant to test the catalytic degradation performance. The degradation experiment is carried out in a 150 mL brown serum vial, and the bottle opening is sealed with a butyl rubber plug. The specific steps are as follows: first, weigh 0.25 g of catalyst (2.5 g / L, vacuum sealed) and disperse it into 100 mL of 2,4,6-trichlorophenol aqueous solution (10 mg / L). Then, add 0.27 g of ammonium persulfate (12 mM) to start the reaction and seal the serum bottle. Place the above serum bottle in a constant temperature shaking incubator at 25°C and perform the experiment at a rotation speed of 180 r / min. Sample the reaction mixture at specific times (0 min, 20 min, 40 min, 60 min) and separate the catalyst material using magnetic separation technology. Then, collect 1.2 mL of supernatant, filter it with a 0.22 μm PTFE membrane, and place the filtered sample in a liquid chromatography injection bottle containing 50 μL of methanol for timely quenching. Identify the degradation intermediates in the solution at different times by liquid chromatography tandem mass spectrometry (LC-MS, Xevo G2 Qtof). Negative ion mass spectrometry scanning is used for analysis, with a scanning range of 50 ~ 500 m / z. The detection conditions are as follows: Kinetex C18 column (2.6 μm, 100×2.1 mm, USA); mobile phase is acetonitrile (0.1% formic acid, A phase) and water (0.1% formic acid, B phase), with a flow rate of 0.3 mL / min; sample size is 2 μL; gradient elution program (min, B%) is (0, 95), (1, 95), (6, 50), (10, 20), (13, 10), (15, 90) and (20, 95). Then, use ECOSAR software to evaluate the biological toxicity of 2,4,6-trichlorophenol and intermediates. As shown in Figure 5 , Figure 6 , Figure 7 , Figure 8 can be seen, all intermediates are effectively cracked in subsequent continuous degradation to form low molecular weight products, significantly reducing their biological toxicity, and ultimately reaching a harmless level.

[0128] The above describes the present application in detail. For those skilled in the art, without departing from the purpose and scope of the present application, and without unnecessary experiments, the present application can be implemented in a wide range of equivalent parameters, concentrations and conditions. Although the present application gives a special example, it should be understood that further improvements can be made to the present application. In summary, according to the principle of the present application, this application intends to include any change, use or improvement of the present application, including changes made by conventional techniques known in the art, which deviates from the range disclosed in the present application.

Claims

1. Use of a high-level oxidation process catalyst in high-level oxidation treatment of industrial organic wastewater, The high-level oxidation process catalyst is prepared by a method comprising the following steps: (1) grinding natural iron ore and natural manganese ore particles respectively and then performing preliminary screening through a 20-mesh sieve; (2) under inert gas protection, the sieved iron ore particles and manganese ore particles obtained in step (1) are respectively added to a ball mill for ball milling treatment to obtain ball-milled iron ore powder and manganese ore powder; (3) the ball-milled iron ore powder and manganese ore powder obtained in step (2) are mixed in a certain proportion and then added to a ball mill for further ball milling treatment to obtain micron-sized iron-manganese bimetallic composite mineral catalyst; (4) the biomass is soaked in a solution containing a heteroelement reagent, and then dried and placed in a tube furnace for pyrolysis under inert gas atmosphere at a certain temperature for a certain time to obtain heteroelement-doped biochar; (5) the micron-sized iron-manganese bimetallic composite mineral catalyst obtained in step (3) is mixed with the heteroelement-doped biochar obtained in step (4) and ball milled under inert gas to obtain micron-sized iron-manganese bimetallic composite mineral catalyst supported by heteroelement-doped biochar; The heteroelement reagent is urea.

2. Use according to claim 1, characterized in that, In step (1), the natural iron ore is at least one of magnetite, hematite, siderite, ilmenite, pyrite, limonite and iron spinel; and the manganese ore is at least one of pyrolusite, rhodochrosite, hydro manganese, brown manganese, black manganese, rhodostannite and manganese spinel. In steps (2) and (3), the grinding body used for ball milling treatment is zirconia ball, and the weight ratio of zirconia ball to mineral is 30-60:1; The ball milling speed is 200-600 rpm, and the ball milling time is 8-16 h.

3. Use according to claim 1, characterized in that, In step (2), the particle size of the ball-milled iron ore powder and manganese ore powder is in the range of 0-8 μm, but not 0; In step (3), the mixing mass ratio of the iron ore powder and the manganese ore powder is 3:1-1:

3.

4. Use according to claim 3, characterized in that, In step (3), the mixing mass ratio of the iron ore powder and the manganese ore powder is 1:

1.

5. The use according to claim 1, characterized in that, In step (3), the particle size of the micron-sized iron-manganese bimetallic composite mineral catalyst is in the range of 0-3.5 μm, but not 0.

6. Use according to claim 1, characterized in that, The biomass is at least one of waste wood, straw, rice husk and coconut shell.

7. Use according to claim 6, characterized in that, The biomass is straw; The mass ratio of urea to straw is 3:1-1:3; The soaking time is 8-16 h; The drying time is 12-14 h; The inert gas used in the tube furnace calcination process is N2, the calcination time is 2-6 h, and the temperature is 600-1200℃.

8. The use according to claim 1, characterized in that, In step (5), the mass ratio of the heteroelement-doped biochar to the micron-sized iron-manganese bimetallic composite mineral catalyst is 3:1-1:

3.

9. The use according to claim 1, characterized in that, In the use, the micron-sized iron-manganese bimetallic composite mineral catalyst supported by heteroelement-doped biochar is used to activate persulfate to degrade chlorophenol organic pollutants in industrial organic wastewater; In the use, the persulfate is permonosulfate and perdisulfate; The chlorophenol organic pollutants include 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol; The dosage of the hetero-element doped biochar loaded micron-sized iron-manganese bimetallic composite mineral catalyst is 0.5-3 g / L, the concentration of persulfate is 3-15 mM, and the initial concentration of chlorophenol organic pollutants in the chlorophenol organic wastewater is 1-20 mg / L.

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