Iron carbide composite straw carbon nano material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of wastewater treatment, and provides an iron carbide composite straw carbon nano material as well as a preparation method and application thereof. The method comprises the following steps: mixing an anhydrous ferric chloride solution, a glucose solution and a melamine solution to obtain a mixed solution; stirring and mixing the mixed solution and the straw powder, performing wet grinding, separating wet grinding products, and drying to obtain a solid; and sintering the solid in a nitrogen atmosphere to obtain the iron carbide composite straw carbon nano material. The straw charcoal is used for modifying iron carbide, the iron carbide composite straw charcoal nano material with high reaction activity and high stability is obtained, persulfate can be activated in a wide pH range and high-salt environment, nucleophilic reaction of # imgabs0 # and persulfate is promoted, and efficient degradation of various new pollutants in high-salt pharmaceutical and chemical wastewater is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to an iron carbide composite straw carbon nanomaterial and a preparation method and application thereof. Background Art

[0002] High-salt pharmaceutical chemical wastewater comes from pharmaceutical chemical production. The acidic and alkaline materials used in this process are usually discharged in the form of inorganic salts after treatment. At the same time, some new pollutants and toxic substances will be formed, resulting in wastewater with high salinity, complex composition, and difficult degradation. Endocrine disruptors are widely present in wastewater discharge. These substances are persistent, bioaccumulative, carcinogenic, etc. They can also harm the ecological environment and human health through the food chain or water cycle, and have become an important environmental issue of global concern. and High concentrations of inorganic salt ions such as ions restrict the growth of microorganisms, thereby reducing the operating effect of the traditional biofilm method. For this reason, catalytic oxidation is usually used to degrade the refractory organic matter in sewage and improve its biodegradability. For pharmaceutical and chemical wastewater, ozone and Fenton-based hydroxyl radical ( ) Advanced oxidation process to degrade endocrine disruptors. However, high concentrations of Will quench and and produce Therefore, achieving efficient and low-cost degradation of endocrine disruptors in a high-salinity environment is an urgent problem to be solved in the current treatment of high-salinity pharmaceutical and chemical wastewater.

[0003] In recent years, persulfate advanced oxidation technology has attracted widespread attention due to its ability to efficiently degrade refractory pollutants. and sulfate radicals ( ) and other strong oxidizing free radicals. The activation methods include input of energy, transition metal ions and their catalytic materials. Persulfate can also be directly Activation produces active species, but its efficiency is low and it is difficult to effectively degrade pollutants. 3 C) Due to its special structure of carbon atoms infiltrating into the iron lattice, it has high hardness, high thermal stability, corrosion resistance, magnetism and controllable reaction sites, and has attracted extensive attention in sewage treatment and environmental remediation. However, its process of catalyzing persulfate to produce free radicals to degrade endocrine disruptors may be Interference, and its low charge conduction capacity limits its catalytic performance towards persulfate.

[0004] As an easily available and low-cost material carrier, straw biochar has a graphene-like structure on its surface that can not only increase the electron transfer rate, but also activate persulfate to produce non-oxidative free radical pathways. However, Fe atoms need to be introduced as In addition, the graphene carbon layer is used to encapsulate Fe 3 C nanoparticles, using "penetrating" electrons to catalyze reactions, can isolate active sites from the reaction medium, thereby increasing Fe 3 Activity and stability of C nanoparticles.

[0005] Therefore, the study obtained an iron carbide composite straw carbon nanomaterial, which promotes the nucleophilic reaction of persulfate and chloride ions to produce a large number of active species through adsorption and electron transfer, and realizes the rapid degradation of new pollutants, which is of great significance. Summary of the invention

[0006] The purpose of the present invention is to provide an iron carbide composite straw carbon nanomaterial and a preparation method and application thereof in order to overcome the deficiencies of the prior art.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for preparing an iron carbide composite straw carbon nanomaterial, comprising the following steps: 1) mixing anhydrous ferric chloride solution, glucose solution and melamine solution to obtain a mixed solution; 2) The mixed liquid and the straw powder are stirred and mixed, and then wet-milled. The wet-milled product is separated and then dried to obtain a solid; 3) Sintering the solid in a nitrogen atmosphere to obtain iron carbide composite straw carbon nanomaterials.

[0008] Preferably, in step 1), the mass ratio of anhydrous ferric chloride in the anhydrous ferric chloride solution, glucose in the glucose solution, and melamine in the melamine solution is 2.7-3.3:2.7-3.3:1.8-2.2; In the anhydrous ferric chloride solution, the mass volume ratio of anhydrous ferric chloride to the solvent is 2.7~3.3g:35~45mL; in the glucose solution, the mass volume ratio of glucose to the solvent is 2.7~3.3g:55~65mL; ​​in the melamine solution, the mass volume ratio of melamine to the solvent is 1.8~2.2g:90~110mL.

[0009] Preferably, the solvents in the anhydrous ferric chloride solution, the glucose solution and the melamine solution are all a mixture of anhydrous ethanol and water; in the anhydrous ferric chloride solution, the volume ratio of anhydrous ethanol to water is 0.8-1.2:0.8-1.2; in the glucose solution, the volume ratio of anhydrous ethanol to water is 1.7-2.3:1; in the melamine solution, the volume ratio of anhydrous ethanol to water is 0.8-1.2:0.8-1.2; Step 1) The mixing temperature is 55-65° C. and the mixing time is 25-35 min.

[0010] Preferably, the mass ratio of the straw powder in step 2) to the anhydrous ferric chloride in the anhydrous ferric chloride solution in step 1) is 0.45-0.55:2.7-3.3; and the particle size of the straw powder is ≤200 mesh.

[0011] Preferably, the stirring and mixing temperature in step 2) is 55-65° C., and the stirring and mixing time is 1-2 h; The wet grinding speed is 550-650 rpm, the wet grinding time is 2.5-3.5 h, and the wet grinding medium is grinding beads with a particle size of 2 mm; The drying temperature is 170-190° C., and the drying time is 10-14 hours.

[0012] Preferably, in step 3), the sintering temperature is 750-850° C., the sintering time is 2.5-3.5 h, and the heating rate to the sintering temperature is 3-7° C. / min.

[0013] The invention also provides an iron carbide composite straw carbon nano material prepared by the preparation method.

[0014] The invention also provides the use of the iron carbide composite straw carbon nanomaterial in activating persulfate to degrade new pollutants.

[0015] Preferably, the iron carbide composite straw carbon nanomaterial, the new pollutant solution, the chloride ion solution and water are mixed and shaken for adsorption, and then a persulfate solution is added for reaction; The mass volume ratio of iron carbide composite straw carbon nanomaterials and new pollutant solution is 9~11mg:4~6mL; the volume ratio of new pollutant solution, chloride ion solution, water and persulfate solution is 4~6:0.4~0.6:42~45:0.8~1.2.

[0016] Preferably, the new pollutants include endocrine disruptors and PPCPs; the concentration of the new pollutant solution is 45-55 μmol / L, the concentration of the chloride ion solution is 0.8-1.2 mol / L, and the concentration of the persulfate solution is 45-55 mmol / L; and the pH value of the reaction is 6-6.4.

[0017] The beneficial effects of the present invention include the following: 1) The present invention realizes the encapsulation of iron carbide nanoparticles in straw biochar through ball milling and sintering methods, develops a low-cost, highly stable and reusable persulfate catalytic material, promotes the nucleophilic reaction of persulfate and chloride ions through adsorption and electron transfer to produce a large number of active species, realizes the rapid degradation of new pollutants, and provides technical guidance for the deep treatment of high-salt pharmaceutical and chemical wastewater.

[0018] 2) The present invention uses straw biochar to modify iron carbide to obtain an iron carbide composite straw carbon nanomaterial with high reaction activity and strong stability, which can activate persulfate in a wide pH range and high-salt environment, promote the nucleophilic reaction of chloride ions and persulfate, and achieve efficient degradation of a variety of new pollutants in high-salt pharmaceutical and chemical wastewater, such as diethylstilbestrol, methyltestosterone, megestrol, cortisone, boldenone, and androstenedione, as well as PPCPs such as ibuprofen and demetronidazole. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The degradation effects of chloride ions, persulfate and different iron carbide composite nanomaterials on 17 β-estradiol, wherein a is the persulfate / chloride ion system of comparative application example 1-2, b is the persulfate / catalyst material system of comparative application example 1-1, and c is the persulfate / catalyst material / chloride ion system of application example 1; Figure 2 The effect of different pH values ​​on persulfate / Fe 3 C-BC / chloride system and persulfate / Fe 3 The effect of C-BC system on the degradation of 17β-estradiol; Figure 3 The effect of different concentrations of chloride ions on the Fe 3 Effect of C-BC activation on the degradation of 17 β-estradiol by persulfate; Figure 4 is the Fe of Example 1 3 Fe of C-BC and Comparative Example 1 3 The effect of C-activated persulfate on the degradation of endocrine disruptors in actual chlorinated wastewater, where a is Fe 3 C removal rate, b is Fe 3 Concentrations of endocrine disruptors before and after C-BC treatment; Figure 5 is the Fe of Example 1 3 Cytotoxicity of persulfate activated by C-BC on ibuprofen system in chloride ion background, where a is ibuprofen removal rate and b is cell survival rate; Figure 6 is the Fe of Example 13 The cytotoxicity of C-BC in the system of persulfate activation and degradation of dimetridazole in the background of chloride ions, where a is the removal rate of dimetridazole and b is the cell survival rate; Figure 7 is the Fe of Example 1 3 The cytotoxicity in the C-BC activated persulfate degradation system of dimetridazole, where a is the dimetridazole removal rate and b is the cell survival rate; Figure 8 Fe of Comparative Example 1 3 C and Fe of Example 1 3 Reaction mechanism of C-BC activation of persulfate / chloride ion system, where a is the EPR capture spectrum of hydroxyl radicals and b is the free chlorine generation diagram. DETAILED DESCRIPTION

[0020] The present invention provides a method for preparing an iron carbide composite straw carbon nanomaterial, comprising the following steps: 1) mixing anhydrous ferric chloride solution, glucose solution and melamine solution to obtain a mixed solution; 2) The mixed liquid and the straw powder are stirred and mixed, and then wet-milled. The wet-milled product is separated and then dried to obtain a solid; 3) Sintering the solid in a nitrogen atmosphere to obtain iron carbide composite straw carbon nanomaterials.

[0021] In the present invention, the mass ratio of anhydrous ferric chloride in the anhydrous ferric chloride solution, glucose in the glucose solution, and melamine in the melamine solution in step 1) is preferably 2.7-3.3:2.7-3.3:1.8-2.2, more preferably 2.9-3.1:2.9-3.1:1.9-2.1, and more preferably 3:3:2; In the anhydrous ferric chloride solution, the mass volume ratio of anhydrous ferric chloride to the solvent is preferably 2.7~3.3g:35~45mL, more preferably 2.9~3.1g:38~42mL, and more preferably 3g:40mL; in the glucose solution, the mass volume ratio of glucose to the solvent is preferably 2.7~3.3g:55~65mL, more preferably 2.8~3.2g:57~63mL, and more preferably 3g:60mL; in the melamine solution, the mass volume ratio of melamine to the solvent is preferably 1.8~2.2g:90~110mL, more preferably 1.9~2.1g:95~105mL, and more preferably 2g:100mL.

[0022] In the present invention, the solvents in the anhydrous ferric chloride solution, the glucose solution and the melamine solution are preferably a mixture of anhydrous ethanol and water; in the anhydrous ferric chloride solution, the volume ratio of anhydrous ethanol to water is preferably 0.8-1.2:0.8-1.2, more preferably 0.9-1.1:0.9-1.1, and more preferably 1:1; in the glucose solution, the volume ratio of anhydrous ethanol to water is preferably 1.7-2.3:1, more preferably 1.8-2.2:1, and more preferably 2:1; in the melamine solution, the volume ratio of anhydrous ethanol to water is preferably 0.8-1.2:0.8-1.2, more preferably 0.9-1.1:0.9-1.1, and more preferably 1:1; In step 1), the mixing temperature is preferably 55-65° C., more preferably 58-62° C., more preferably 60° C., and the mixing time is preferably 25-35 min, more preferably 28-32 min, more preferably 30 min.

[0023] In the present invention, the mass ratio of the straw powder in step 2) to the anhydrous ferric chloride in the anhydrous ferric chloride solution in step 1) is preferably 0.45-0.55:2.7-3.3, more preferably 0.48-0.52:2.8-3.2, and more preferably 0.5:3; the particle size of the straw powder is preferably ≤200 mesh.

[0024] In the present invention, the stirring and mixing temperature in step 2) is preferably 55-65°C, more preferably 58-62°C, more preferably 60°C, and the stirring and mixing time is preferably 1-2h, more preferably 1.5h; The wet grinding speed is preferably 550-650 rpm, more preferably 580-620 rpm, more preferably 600 rpm, the wet grinding time is preferably 2.5-3.5 h, more preferably 3 h, and the wet grinding medium is preferably grinding beads with a particle size of 2 mm; The drying temperature is preferably 170-190° C., more preferably 175-185° C., more preferably 180° C., and the drying time is preferably 10-14 h, more preferably 11-13 h, more preferably 12 h.

[0025] In the present invention, the wet grinding process is to repeat operation and interruption alternately, one operation and one interruption is one cycle, a total of 18 cycles, each operation time is 9 to 11 minutes, each interruption time is 7 to 9 minutes, and the total operation time is the wet grinding time.

[0026] In the present invention, the sintering temperature in step 3) is preferably 750-850°C, more preferably 780-820°C, and more preferably 800°C. The sintering time is preferably 2.5-3.5h, and more preferably 3h. The heating rate to the sintering temperature is preferably 3-7°C / min, more preferably 4-6°C / min, and more preferably 5°C / min.

[0027] The invention also provides an iron carbide composite straw carbon nano material prepared by the preparation method.

[0028] The invention also provides the use of the iron carbide composite straw carbon nanomaterial in activating persulfate to degrade new pollutants.

[0029] In the present invention, iron carbide composite straw carbon nanomaterial, new pollutant solution, chloride ion solution and water are mixed and shaken for adsorption, and then a persulfate solution is added for reaction; The mass volume ratio of iron carbide composite straw carbon nanomaterial and new pollutant solution is preferably 9~11 mg:4~6 mL, further preferably 9.5~10.5 mg:4.5~5.5 mL, and more preferably 10 mg:5 mL; the volume ratio of new pollutant solution, chloride ion solution, water and persulfate solution is preferably 4~6:0.4~0.6:42~45:0.8~1.2, further preferably 4.5~5.5:0.45~0.55:43~44:0.9~1.1, and more preferably 5:0.5:43.5:1.

[0030] In the present invention, the new pollutants preferably include endocrine disruptors and PPCPs; the concentration of the new pollutant solution is preferably 45~55μmol / L, more preferably 48~52μmol / L, more preferably 50μmol / L, the concentration of the chloride ion solution is preferably 0.8~1.2mol / L, more preferably 0.9~1.1mol / L, more preferably 1mol / L, and the concentration of the persulfate solution is preferably 45~55mmol / L, more preferably 48~52mmol / L, more preferably 50mmol / L.

[0031] In the present invention, the pH value of the reaction is preferably 6-6.4, more preferably 6.1-6.3, and more preferably 6.2; the time of oscillation adsorption is preferably 18-22 min, more preferably 19-21 min, and more preferably 20 min.

[0032] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0033] In the examples, the stirring speed is 600 rpm.

[0034] Example 1

[0035] The straw powder was sieved on a 200-mesh standard sieve to screen out straw powder with a particle size of less than or equal to 200 mesh. 3 g of anhydrous ferric chloride was added to 40 mL of a mixed solution (the volume ratio of anhydrous ethanol to water was 1:1), and stirred thoroughly until completely dissolved to obtain an anhydrous ferric chloride solution; 3 g of glucose was added to 20 mL of water, stirred until completely dissolved, and then 40 mL of anhydrous ethanol was added and mixed evenly to obtain a glucose solution; 2 g of melamine was added to 100 mL of a mixed solution (the volume ratio of anhydrous ethanol to water was 1:1), and stirred at a constant temperature with a magnetic stirrer until the solution was colorless to obtain a melamine solution.

[0036] The above-mentioned anhydrous ferric chloride solution, glucose solution and melamine solution were added to a 250 mL conical flask, and after constant temperature magnetic stirring at 60 ° C for 30 minutes, 0.5 g of sieved straw powder was added, and after stirring at 60 ° C for 1.5 hours, a suspension was obtained. Zirconia beads with a particle size of 2 mm (the mass volume ratio of zirconium oxide beads to the suspension is 50 g: 40 mL) were used for wet grinding at a speed of 600 rpm for 3 hours (the wet grinding process was interrupted for 8 minutes after every 10 minutes of operation, and the operation and interruption were repeated alternately, and the operation and interruption were repeated 18 times in total). After wet grinding, the solution obtained after separating the grinding beads with a sieve less than 2 mm was dried in an oven at 180 ° C for 12 hours. After the solid was ground into a uniform and fine powder, it was loaded into a porcelain boat and placed in a tubular furnace at N 2 The temperature was raised to 800°C at a rate of 5°C / min under the atmosphere and maintained at 800°C for 3 h. After the tube furnace was cooled naturally, the porcelain boat was taken out and the black solid in the porcelain boat was ground into powder to obtain iron carbide composite straw carbon nanomaterial (Fe 3 C-BC nanomaterials).

[0037] Example 2

[0038] The straw powder was sieved on a 200-mesh standard sieve to screen out straw powder with a particle size of less than or equal to 200 mesh. 2.7 g of anhydrous ferric chloride was added to 38 mL of a mixed solution (the volume ratio of anhydrous ethanol to water was 0.9:1.1), and stirred thoroughly until completely dissolved to obtain an anhydrous ferric chloride solution; 2.7 g of glucose was added to 19 mL of water, stirred until completely dissolved, and then 38 mL of anhydrous ethanol was added and mixed evenly to obtain a glucose solution; 1.8 g of melamine was added to 95 mL of a mixed solution (the volume ratio of anhydrous ethanol to water was 0.9:1.1), and magnetic stirring was performed at a constant temperature until the solution was colorless to obtain a melamine solution.

[0039] The above-mentioned anhydrous ferric chloride solution, glucose solution and melamine solution were added to a 250 mL conical flask, and after constant temperature magnetic stirring for 32 minutes at 58°C, 0.48 g of sieved straw powder was added, and after stirring at 58°C for 2 hours, a suspension was obtained. Zirconia beads with a particle size of 2 mm (the mass volume ratio of zirconium oxide beads to the suspension is 50 g: 40 mL) were used for wet grinding at a speed of 580 rpm for 3.5 hours (the wet grinding process was interrupted for 7 minutes after every 9 minutes of operation, and the operation and interruption were repeated alternately, and the operation and interruption were repeated 18 times in total). After wet grinding, the solution obtained after separating the grinding beads with a sieve of less than 2 mm was dried in an oven at 175°C for 13 hours. After the solid was ground into a uniform and fine powder, it was loaded into a porcelain boat and placed in a tubular furnace at N 2 The temperature was raised to 780°C at a rate of 4°C / min under an atmosphere and maintained at 780°C for 3.5 h. After the tube furnace was cooled naturally, the porcelain boat was taken out and the black solid in the porcelain boat was ground into powder to obtain iron carbide composite straw carbon nanomaterial (Fe 3 C-BC nanomaterials).

[0040] Example 3

[0041] The straw powder was sieved on a 200-mesh standard sieve to screen out straw powder with a particle size of less than or equal to 200 mesh. 3.1 g of anhydrous ferric chloride was added to 42 mL of a mixed solution (the volume ratio of anhydrous ethanol to water was 1.1:0.9), and stirred thoroughly until completely dissolved to obtain an anhydrous ferric chloride solution; 3.1 g of glucose was added to 21 mL of water, stirred until completely dissolved, and then 39 mL of anhydrous ethanol was added and mixed evenly to obtain a glucose solution; 2.1 g of melamine was added to 105 mL of a mixed solution (the volume ratio of anhydrous ethanol to water was 1.1:0.9), and magnetic stirring was performed at a constant temperature until the solution was colorless to obtain a melamine solution.

[0042] The above-mentioned anhydrous ferric chloride solution, glucose solution and melamine solution were added to a 250 mL conical flask, and after constant temperature magnetic stirring at 62 ° C for 28 minutes, 0.52 g of sieved straw powder was added, and after stirring at 62 ° C for 1 hour, a suspension was obtained. Zirconia beads with a particle size of 2 mm (the mass volume ratio of zirconium oxide beads to the suspension is 50 g: 40 mL) were used for wet grinding at a speed of 650 rpm for 2.5 hours (the wet grinding process was interrupted for 9 minutes after every 11 minutes of operation, and the operation and interruption were repeated alternately, and the operation and interruption were repeated 18 times in total). After wet grinding, the solution obtained after separating the grinding beads with a sieve less than 2 mm was dried in an oven at 185 ° C for 11 hours. After the solid was ground into a uniform and fine powder, it was loaded into a porcelain boat and placed in a tubular furnace at N 2The temperature was raised to 820°C at a rate of 6°C / min under the atmosphere and maintained at 820°C for 2.5 h. After the tube furnace was cooled naturally, the porcelain boat was taken out and the black solid in the porcelain boat was ground into powder to obtain iron carbide composite straw carbon nanomaterial (Fe 3 C-BC nanomaterials).

[0043] Comparative Example 1 The steps of “adding 2 g of melamine to 100 mL of a mixed solution (the volume ratio of anhydrous ethanol to water is 1:1) and stirring at a constant temperature with a magnetic stirrer until the solution becomes colorless to obtain a melamine solution” and “stirring at a constant temperature with a magnetic stirrer at 60° C. for 30 min and then adding 0.5 g of sieved straw powder” in Example 1 were omitted. The melamine solution and straw powder were not added to the conical flask, and wet grinding was not performed. After the mixture was uniformly mixed with a magnetic stirrer, the mixture was directly dried. The other conditions were the same as those in Example 1 to obtain an iron carbide material (Fe 3 C material).

[0044] Comparative Example 2 The step of “adding 0.5 g of sieved straw powder after magnetic stirring at 60° C. for 30 min” in Example 1 was omitted. No straw powder was added to the conical flask, no wet grinding was performed, and the mixture was evenly mixed by magnetic stirring and then directly dried. The other conditions were the same as those in Example 1 to obtain carbon-nitrogen coated iron carbide nanomaterial (Fe 3 C@CN).

[0045] Comparative Example 3 The "addition of 0.5 g of sieved straw powder" in Example 1 was replaced by "addition of 0.5 g of multi-walled carbon nanotubes", and the mixture was mixed evenly by magnetic stirring without wet grinding, and then directly dried. The other conditions were the same as those in Example 1, and the carbon-nitrogen core-shell-wrapped iron carbide-loaded carbon nanotube nanomaterial (Fe 3 C@CN-CNTs).

[0046] Comparative Example 4 The "addition of 0.5 g of sieved straw powder" in Example 1 was replaced by "addition of 0.5 g of nitrogen-doped multi-walled carbon nanotubes", and the mixture was mixed evenly by magnetic stirring without wet grinding, and then directly dried. The other conditions were the same as those in Example 1, and carbon-nitrogen-encapsulated iron carbide loaded with nitrogen-doped carbon nanotubes (Fe 3 C@CN-NCNTs).

[0047] Comparative Example 5 The step of “adding 2 g of melamine to 100 mL of a mixed solution (the volume ratio of anhydrous ethanol to water is 1:1) and stirring at a constant temperature with a magnetic stirrer until the solution becomes colorless to obtain a melamine solution” in Example 1 was omitted, and no melamine was added to the conical flask; the step of “adding 0.5 g of sieved straw powder” in Example 1 was replaced with “adding 0.5 g of nitrogen-doped multi-walled carbon nanotubes”, and the mixture was directly dried after being uniformly mixed with a magnetic stirrer without wet grinding. The other conditions were the same as in Example 1, and an iron carbide-loaded carbon nanotube nanomaterial (Fe 3 C-CNTs).

[0048] Application Example 1 Effect of the materials of Example 1 and Comparative Examples 1 to 5 on the degradation of 17β-estradiol in a catalyst / persulfate / chloride ion reaction system At room temperature, 43.5 mL of pure water, 5 mL of 50 µmol / L 17β-estradiol solution, and 0.5 mL of 1 mol / L chloride ion solution were placed in a 50 mL centrifuge tube, 10 mg of the catalyst material of Example 1 was added, and after 20 min of oscillation adsorption, 1 mL of 50 mmol / L persulfate solution (PMS) was added to start the reaction, and the pH value of the reaction solution was adjusted to 6.2 using 1 mol / L NaOH solution. 0.2 mL of the sample was taken 5 minutes after the start of the reaction, mixed with 0.2 mL of methanol and 0.05 mL of a mixed quencher (the volume ratio of methanol, thiosulfate solution and L-ascorbic acid solution was 5:2:3, the concentration of thiosulfate was 50 mmol / L, and the concentration of L-ascorbic acid solution was 57 mmol / L), and then filtered through a polyethersulfone (PES) filter head with a pore size of 0.45 μm into a brown liquid sample bottle, and the remaining 17β-estradiol content in each sample was determined by high performance liquid chromatography. Under the same experimental conditions, the materials in Example 1 were replaced with Fe of Comparative Example 1 respectively. 3 C. Fe of Comparative Example 2 3 C@CN, Fe of Comparative Example 3 3 C@CN-CNTs, Fe 3 C@CN-NCNTs, Fe 3 C-CNTs, to examine the effect of persulfate activation on the performance of different iron carbide nanocomposites.

[0049] Comparative Application Example 1-1 The 0.5 mL of 1 mol / L chloride ion solution in Application Example 1 was omitted, and other conditions were the same as those in Application Example 1.

[0050] Comparative Application Example 1-2 The 10 mg catalyst materials of Example 1 and Comparative Examples 1 to 5 in Application Example 1 were omitted, and 0.2 mL of samples were taken at sampling points of 5 min, 10 min, 20 min, and 30 min after the start of the reaction. Other conditions were the same as those in Application Example 1.

[0051] The synergistic effect of chloride ions, persulfate and iron carbide nanocomposites on the degradation of 17β-estradiol was examined. Figure 1 As shown in Figure a, a is the persulfate / chloride ion system of comparative application example 1-2, b is the persulfate / catalyst material system of comparative application example 1-1, and c is the persulfate / catalyst material / chloride ion system of application example 1. As shown in Figure a, 1mmol / L PMS and 10mmol / L The degradation effect on 17β-estradiol was weak, less than 40% within 30 minutes; as shown in Figure b, in the absence of chloride ions, the degradation rate of 17β-estradiol by persulfate activated by different iron carbide nanocomposites can reach 25.0~93.5% within 5 minutes. As shown in Figure c, after adding chloride ions and catalysts at the same time, the degradation rate of 17β-estradiol by persulfate activated by different iron carbide nanocomposites was improved, among which Fe 3 C@CN-NCNTs, Fe 3 C and Fe 3 The degradation of 17β-estradiol by C@CN activated persulfate was weak, which was 53.4%, 60.1% and 36.8% within 5 min, respectively. 3 C@CN-CNTs can reach 87.6%. Under the same experimental conditions, Fe 3 C-CNTs and Fe 3 The degradation rate of 17β-estradiol by C-BC activated persulfate can reach 100%, among which Fe 3 C-BC is slightly stronger than Fe 3C-CNTs, and the degradation rate is nearly 1 to 3 times higher than that of other materials. The results show that the degradation rate of 17β-estradiol by chloride ions and persulfate activated by iron carbide nanomaterials is higher than that of the persulfate system without adding chloride ions or iron carbide nanomaterials. The synergistic effect between chloride ions, persulfate and iron carbide nanomaterials can significantly improve the degradation rate of 17β-estradiol in wastewater. Compared with traditional iron carbide materials, the iron carbide-loaded straw biochar nanocomposite material used in the present invention is not only low in cost, but also can significantly improve the performance of activated persulfate in degrading endocrine disruptors under the background of high concentration of chloride ions, thereby improving the application value of iron carbide-based nanomaterials. The cost of straw biochar is much lower than that of carbon nanotubes, and the costs of straw powder and carbon nanotubes are 0.006 yuan / g and 10 yuan / g, respectively. Under the background of high concentration of chloride ions, when treating high-salt pharmaceutical and chemical wastewater, the treatment cost of using iron carbide-loaded straw biochar is much lower than that of using iron carbide-loaded carbon nanotubes.

[0052] Application Example 2 Effect of different pH values ​​on persulfate / Fe 3 Effect of C-BC / chloride ion system on the degradation of 17 β-estradiol At room temperature, 43.5 mL of pure water, 5 mL of 50 µmol / L 17β-estradiol solution, and 0.5 mL of 1 mol / L chloride ion solution were placed in a 50 mL centrifuge tube, 10 mg of the catalyst material of Example 1 was added, and after 20 min of oscillation adsorption, 1 mL of 50 mmol / L persulfate solution (PMS) was added to start the reaction, and the pH value of the reaction solution was adjusted to 6.2 using 1 mol / L NaOH solution. 0.2 mL of the sample was taken 3 min after the start of the reaction, mixed with 0.2 mL of methanol and 0.05 mL of a mixed quencher (the volume ratio of methanol, thiosulfate solution and L-ascorbic acid solution was 5:2:3, the concentration of thiosulfate was 50 mmol / L, and the concentration of L-ascorbic acid solution was 57 mmol / L), and then filtered through a polyethersulfone filter with a pore size of 0.45 μm into a brown liquid sample bottle, and the remaining 17β-estradiol content in each sample was determined by high performance liquid chromatography. Under the same experimental conditions, 1 mol / L NaOH solution and 0.1 mol / L H 2 SO 4 The pH value of the reaction solution was adjusted to 4 and 8 respectively to test the effect of different pH values ​​on the persulfate / Fe 3 Effect of C-BC / chloride ion system on the degradation of 17β-estradiol.

[0053] Comparative Application Example 2-1 The 0.5 mL of 1 mol / L chloride ion in Application Example 2 was omitted, and other conditions were the same as those in Application Example 2.

[0054] Effect of different pH values ​​on persulfate / Fe 3 C-BC / chloride system and persulfate / Fe 3 Effects of C-BC system on the degradation of 17 β-estradiol Figure 2 As shown in the figure, under the conditions of pH 4, 6.2 and 8, the persulfate / Fe 3 The degradation rate of 17 β-estradiol by C-BC / chloride ion system can reach 100% within 3 min. Under the conditions of pH 4, 6.2 and 8, the degradation rate of 17 β-estradiol by persulfate / Fe 3 The degradation rates of 17β-estradiol in the C-BC system within 3 min were 100%, 88.6% and 92.6%, respectively. The results showed that the iron carbide-loaded biochar nanocomposite had good activity under a wide range of acid and alkaline conditions, and had a good degradation effect on 17β-estradiol in simulated wastewater. The pH range was wide, which was conducive to practical application.

[0055] Application Example 3 Effect of different concentrations of chloride ions on the Fe 3 C-BC activation for persulfate degradation Effects of 17 β-estradiol At room temperature, 43.5 mL of pure water, 5 mL of 50 µmol / L 17β-estradiol solution, and 0.5 mL of 1 mol / L chloride ion solution were placed in a 50 mL centrifuge tube (the chloride ion concentration in the centrifuge tube was 10 mmol / L), and 10 mg of Fe 3 C-BC material, after 20 minutes of oscillation adsorption, 1 mL of 50 mmol / L persulfate solution (PMS) was added to start the reaction, and the pH value of the reaction solution was adjusted to 6.2 using 1 mol / L NaOH solution. 0.2 mL of sample was taken 2 minutes after the start of the reaction, mixed with 0.2 mL of methanol and 0.05 mL of a mixed quencher (the volume ratio of methanol, thiosulfate solution and L-ascorbic acid solution was 5:2:3, the concentration of thiosulfate was 50 mmol / L, and the concentration of L-ascorbic acid solution was 57 mmol / L), and then filtered through a polyethersulfone filter with a pore size of 0.45 μm into a brown liquid sample bottle, and the remaining 17β-estradiol content in each sample was determined by high performance liquid chromatography. Under the same experimental conditions, the chloride ion concentration was changed to 1 mmol / L, 2 mmol / L, 5 mmol / L and 20 mmol / L, respectively, to compare the Fe of Example 1 in different chloride ion backgrounds. 3 Effect of C-BC activation on the degradation of 17β-estradiol in wastewater by persulfate.

[0056] Effect of different concentrations of chloride ions on Fe in Example 1 3Effect of persulfate activation by C-BC on the degradation of 17β-estradiol Figure 3 As shown. Figure 3 As shown in the figure, when the chloride ion concentrations were 1mmol / L, 2mmol / L, 5mmol / L, 10mmol / L and 20mmol / L, Fe 3 The degradation rates of 17β-estradiol by C-BC activated persulfate were 96.95%, 96.06%, 96.83%, 96.97% and 97.32%, respectively, which were all higher than the degradation rates in the absence of chloride ions. The results showed that in the presence of chloride ions, when the chloride ion concentration increased in the range of 1~5mmol / L, the degradation rate of 17β-estradiol could be slightly reduced with the increase of chloride ion concentration; but when the chloride ion concentration increased in the range of 10~20mmol / L, the degradation rate of 17β-estradiol could be slightly increased accordingly. This is because when the chloride ion concentration is in the range of 1~5mmol / L, the chloride ions are adsorbed to the active sites on the surface of the material, which may affect the adsorption and reaction of 17β-estradiol on the surface of the material, resulting in a slight inhibition of the degradation of 17β-estradiol; when the chloride ion concentration exceeds 5mmol / L, a large amount of chloride ions are adsorbed to the surface of the material, which may be more conducive to the activation of persulfate to produce free radicals and non-free radical pathways to degrade 17β-estradiol, thereby promoting the degradation of 17β-estradiol.

[0057] Application Example 4: Persulfate and Fe 3 Effect of C-BC on the degradation of endocrine disruptors in actual chlorinated wastewater At room temperature, 48 mL of actual chlorine-containing wastewater (mainly containing 2.3 μg / L diethylstilbestrol, 1.8 μg / L 17β-estradiol, 296.8 ng / L androstenedione, and 5.7 mmol / L chloride ions) was injected into a 50 mL centrifuge tube, and 50 mg of Fe 3 C-BC, after 20 minutes of oscillation adsorption, 2 mL of 50 mmol / L persulfate solution was added to start the reaction. During the experiment, 0.2 mL of samples were taken at 5 min, 10 min, 20 min, 30 min, 40 min, 50 min and 60 min sampling points, respectively, and mixed with 0.2 mL of methanol solution and 0.05 mL of mixed quencher (the volume ratio of methanol, thiosulfate solution and L-ascorbic acid solution was 5:2:3, the concentration of thiosulfate was 50 mmol / L, and the concentration of L-ascorbic acid solution was 57 mmol / L). After being evenly mixed, it was filtered through a 0.22 μM polytetrafluoroethylene (PTFE) filter head into a brown liquid sample bottle, and the residual endocrine disruptor content in the sample was determined by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry. Under the same experimental conditions, the Fe in Example 1 was mixed with 0.2 mL of methanol solution and 0.05 mL of mixed quencher (the volume ratio of methanol, thiosulfate solution and L-ascorbic acid solution was 5:2:3, the concentration of thiosulfate was 50 mmol / L, and the concentration of L-ascorbic acid solution was 57 mmol / L). 3 C-BC is replaced by Fe in Comparative Example 13 C for comparison.

[0058] Fe of Example 1 3 Fe of C-BC and Comparative Example 1 3 The effect of C-activated persulfate for 60 min on the degradation of endocrine disruptors in actual chlorinated wastewater is shown in Figure 2. Figure 4 As shown, where a is Fe 3 C removal rate, b is Fe 3 The concentration of endocrine disruptors before and after C-BC treatment. 3 The adsorption and degradation rates of different endocrine disruptors in actual chlorinated wastewater by C-BC within 20 min were 46.45% (estrogens), 84.55% (17β-estradiol), 14.13% (diethylstilbestrol), 33.82% (prednisolone acetate), 52.12% (megestrol acetate), 23.76% (prednisone), 83.96% (prednisolone), 12.09% (methyltestosterone), 4.9% (cortisone), 12.11% (androstenedione) and 6.15% (boldenone), respectively. The Fe content of comparative example 1 was 0.2477 W·m-1·K-1 and 0.333 W·m-1. 3 C were 29.48% (estradiol), 68.93% (17β-estradiol), 8.63% (diethylstilbestrol), 21.12% (prednisolone acetate), almost none (megestrol acetate), 12.42% (prednisone), 11.11% (prednisolone), 10.15% (methyltestosterone), 14.15% (cortisone), 0.21% (androstenedione) and 7.51% (boldenone).

[0059] like Figure 4 As shown in a, after adding persulfate to activate and degrade for 60 min, Fe 3 The degradation rates of different endocrine disruptors by C-BC activated persulfate system under actual chlorine-containing wastewater conditions were 100% (estrogens), 97.83% (17β-estradiol), 96.52% (diethylstilbestrol), 93.17% (prednisolone acetate), 81.05% (megestrol acetate), 71.79% (prednisone), 61.78% (prednisolone), 59.56% (methyltestosterone), 33.75% (cortisone), 32.8% (androstenedione) and 19.39% (boldenone). 3 When material C was added, the degradation effect of endocrine disruptors in actual chlorinated wastewater weakened within 60 min, and the degradation rates of different endocrine disruptors in actual chlorinated wastewater were 92.65%, 73.69%, 50.37%, 71.95%, 10.18%, 47.51%, 43.19%, 14.1%, 2.88%, 8.45% and 9.13%, respectively.

[0060] In addition, if Figure 4 As shown in b, before the reaction, at 5.7mmol / L Under the background of existence, the concentrations of endocrine disruptors in the actual chlorinated wastewater were 2266.84 ng / L (diethylstilbestrol), 1793.6 ng / L (17β-estradiol), 515.34 ng / L (prednisolone acetate), 296.77 ng / L (androstenedione), 206.11 ng / L (methyltestosterone), 180.24 ng / L (estrone), 91.84 ng / L (prednisone), 41.82 ng / L (prednisolone), 4.89 ng / L (cortisone), 4.43 ng / L (megestrol acetate) and 4.38 ng / L (boldenone). 3 After C-BC, the concentrations of most endocrine disruptors in the actual wastewater dropped below 100 ng / L after 60 min. 3 The degradation rate of endocrine disruptors such as prednisone, prednisolone, methyltestosterone, cortisone and boldenone was lower than 80% after the addition of C-BC. The concentration of these endocrine disruptors in wastewater was 4.38~91.84ng / L, and the concentration after treatment could be reduced to 25.91~0.84ng / L. The results showed that the modified iron carbide-loaded straw biochar nanocomposite had better persulfate activation and pollutant degradation performance than iron carbide nanocomposite. The addition of iron carbide-loaded straw biochar nanocomposite significantly affected the degradation rate of endocrine disruptors in actual chlorine-containing wastewater, and had certain application potential in the treatment of high-salt pharmaceutical and chemical wastewater.

[0061] Application Example 5 At room temperature, 43.5 mL of pure water, 5 mL of 50 µmol / L ibuprofen solution, and 0.5 mL of 1 mol / L chloride ion solution were placed in a 50 mL centrifuge tube, and 10 mg of Fe 3C-BC, after shaking evenly, add 1mL of 50mmol / L persulfate solution to start the reaction, and use 1mol / L NaOH solution to adjust the pH of the reaction solution to 6.2. Take 0.2mL of samples at 0min, 20min, and 80min after the start of the reaction, mix with 0.2mL of methanol and 0.05mL of mixed quencher (the volume ratio of methanol, thiosulfate solution and L-ascorbic acid solution is 5:2:3, the concentration of thiosulfate is 50mmol / L, and the concentration of L-ascorbic acid solution is 57mmol / L), and filter into a brown liquid sample bottle through a PTFE filter with a pore size of 0.22μm, and use a high performance liquid chromatograph to determine the residual ibuprofen content in the sample. In addition, take 10mL of samples at 0min, 20min, and 80min after the start of the reaction, filter through a PES filter with a pore size of 0.45μm, and store. The organic components in the samples were enriched by the solid phase extraction (SPE) process. Subsequently, a control group (no pollutants) and a blank group (no cells inoculated, no pollutants) were set up, and the cell proliferation and activity detection kit (CCK-8) was used to measure the absorbance at 450nm using a Tecan Infinity Pro microplate reader to calculate the cell viability in each plate. Then, according to the equation, cell viability = (sample group 450nm -Blank Group 450nm ) / (control group 450nm -Blank Group 450nm ), the blank group is the absorbance value of the pure culture medium, and the control group is the absorbance value without pollutants. The absorbance measurement value is normalized with the cell-free well to analyze the chloride ion and Fe in Example 1. 3 Cytotoxicity of the C-BC activated persulfate degradation system of ibuprofen. The higher the absorbance value, the lower the cytotoxicity.

[0062] Fe of Example 1 3 Cytotoxicity of persulfate activated by C-BC on ibuprofen system in the context of chloride ions Figure 5 As shown in Figure 1, a is the ibuprofen removal rate and b is the cell survival rate. As shown in Figure a, in the presence of chloride ions, after adding persulfate, the degradation rate of ibuprofen by activated persulfate in the material of Example 1 can reach 100% within 80 minutes at room temperature. As ibuprofen is degraded, as shown in Figure b, the cell survival rate of the system gradually increases, reaching 77.5%, 90.1% and 96.9% at 0min, 20min and 80min, respectively. The results show that at high concentrations Background, after persulfate and Fe 3After C-BC treatment, ibuprofen can be effectively degraded and converted into low-toxic or even non-toxic small molecule products, and these products can be continuously generated, thereby reducing the toxicity of the system and improving the cell survival rate. Therefore, the iron carbide composite biochar nanomaterial of the present invention can effectively degrade the refractory organic matter in high-salt pharmaceutical and chemical wastewater and improve the biodegradability of the wastewater.

[0063] Application Example 6 At room temperature, 43.5 mL of pure water, 5 mL of 50 µmol / L dimethylnidazole solution, and 0.5 mL of 1 mol / L chloride ion solution were placed in a 50 mL centrifuge tube, and 10 mg of Fe 3 C-BC, after shaking evenly, add 1mL of 50mmol / L persulfate solution to start the reaction, and use 1mol / L NaOH solution to adjust the pH of the reaction solution to 6.2. Take 0.2mL of samples at 0min, 30min, and 120min after the start of the reaction, mix with 0.2mL of methanol solution and 0.05mL of mixed quencher (the volume ratio of methanol, thiosulfate solution and L-ascorbic acid solution is 5:2:3, the concentration of thiosulfate is 50mmol / L, and the concentration of L-ascorbic acid solution is 57mmol / L), and filter into a brown liquid sample bottle through a 0.45μM PTFE filter head. The remaining demetridazole content in the sample is determined by high performance liquid chromatography. In addition, 10mL of samples are taken at 0min, 30min, and 120min sampling points, filtered through a 0.22μM PTFE filter head, and stored. The organic components in the sample are enriched through the wastewater SPE process. Subsequently, the absorbance at 450 nm was measured using a Tecan Infinity Pro microplate reader using a CCK-8 kit to calculate the cell viability in each plate. Then, according to the equation, cell viability = (sample group 450nm -Blank Group 450nm ) / (control group 450nm -Blank Group 450nm ), the absorbance measurements were normalized to the cell-free wells to analyze the chloride ions and Fe of Example 1 3 Cytotoxicity of the C-BC activated persulfate degradation system of dimethylnidazole. The higher the absorbance value, the lower the cytotoxicity. Blank and parallel control experiments were set up for all experiments.

[0064] Fe of Example 1 3 Cytotoxicity of C-BC in the degradation of dimetridazole by persulfate activated by chloride ion Figure 6 As shown in Figure a, where a is the removal rate of dimethylnidazole and b is the cell survival rate. As shown in Figure a, in the presence of chloride ions, after adding persulfate, the Fe 3The degradation rate of persulfate activated by C-BC at room temperature reached 94.73% and 100% for dimetridazole within 30min and 120min, respectively. As dimetridazole was degraded, as shown in Figure b, the cell survival rate of the system increased and then slightly decreased, reaching 104.0%, 104.9% and 102.4% at 0min, 30min and 120min, respectively. The results showed that at high concentrations Background, after persulfate and Fe 3 After C-BC treatment, dimetridazole can be effectively degraded. After a long reaction time, a small amount of low-toxic small-molecule organic matter may be generated, which slightly increases the toxicity of the system, but the final cell survival rate remains almost unchanged. Therefore, the iron carbide composite biochar nanomaterial of the present invention can effectively degrade the refractory organic matter in high-salt pharmaceutical and chemical wastewater and improve the biodegradability of the wastewater.

[0065] Application Example 7 Fe of Example 1 3 Cytotoxicity of C-BC activated persulfate degradation of dimetridazole At room temperature, 44 mL of pure water and 5 mL of 50 μmol / L dimethylnitropropene solution were placed in a 50 mL centrifuge tube, and 10 mg of Fe 3 C-BC, after shaking evenly, add 1mL of 50mmol / L persulfate solution to start the reaction, and use 1mol / L NaOH solution to adjust the pH value of the reaction solution to 6.2. Take 0.2mL of samples at 0min, 30min, and 120min after the start of the reaction, mix with 0.2mL of methanol solution and 0.05mL of mixed quencher (the volume ratio of methanol, thiosulfate solution and L-ascorbic acid solution is 5:2:3, the concentration of thiosulfate is 50mmol / L, and the concentration of L-ascorbic acid solution is 57mmol / L), and filter into a brown liquid sample bottle through a PTFE filter with a pore size of 0.22μm, and use high performance liquid chromatography to determine the remaining demetridazole content in the sample. In addition, take 10mL of samples at 0min, 30min, and 120min, filter through a PTFE filter with a pore size of 0.22μm, and store. The organic components in the sample are enriched through the wastewater SPE process. Subsequently, the absorbance at 450 nm was measured using a Tecan Infinity Pro microplate reader using a CCK-8 kit to calculate the cell viability in each plate. Then, according to the equation, cell viability = (sample group 450nm -Blank Group 450nm ) / (control group 450nm -Blank Group 450nm ), the absorbance measurements were normalized to the cell-free wells to analyze the chloride ions and Fe of Example 1 3Cytotoxicity of the C-BC activated persulfate degradation system of dimethylnidazole. The higher the absorbance value, the lower the cytotoxicity.

[0066] Fe of Example 1 3 Cytotoxicity of C-BC activated persulfate degradation of dimetridazole Figure 7 As shown in Figure 1, a is the removal rate of dimetridazole and b is the cell survival rate. As shown in Figure a, the degradation rate of dimetridazole by persulfate activated by persulfate and the material of Example 1 at room temperature reached 93.45% and 100% within 30min and 120min, respectively, which is weaker than the degradation of dimetridazole in the presence of chloride ions. As dimetridazole is degraded, as shown in Figure b, the cell survival rate of the system decreases and then increases, reaching 97.0%, 94.1% and 100.0% at 0min, 30min and 120min, respectively. The results show that after persulfate and Fe 3 After C-BC treatment, dimetridazole can be effectively degraded in the system, and the toxic organic matter generated during the reaction may be converted into low-toxic or even non-toxic small molecule products, which can ultimately reduce the toxicity of the system and improve cell survival rate.

[0067] Fe of Comparative Example 1 3 C and Fe of Example 1 3 Reaction mechanism of C-BC activation of persulfate / chloride ion system At room temperature, take 0.5 mL of 1 mol / L chloride ion, place it in a 50 mL centrifuge tube, add 10 mg Fe 3 C-BC, after 20 minutes of oscillation adsorption, 1 mL of 50 mmol / L persulfate solution was added to start the reaction, and the pH of the reaction solution was adjusted to 6.2. During the experiment, samples were taken at 5 min, 10 min, and 15 min sampling points, and 0.4 mL was taken after filtering through a 0.45 μM PES filter head, mixed with 0.04 mL of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) solution, and oxygen-containing free radicals in the reaction system were detected using an electron paramagnetic resonance (EPR) spectrometer.

[0068] At the 20-minute sampling point, 1.2 mL of sample was taken, and after filtering through a 0.45 μM PES filter head, 0.6 mL of each sample was mixed with 1 mL of pure water and tert-butyl alcohol, respectively, and diluted to 10 mL after standing for 15 to 30 seconds, and then 2.4 mL of 0.5 mol / L sodium bicarbonate solution and 6 mL of 1 mol / L potassium iodide solution were added, shaken, and reacted for 15 minutes. The absorbance of the sample at 325 nm was measured using a UV spectrophotometer. In the same way, 6 mmol / L of methanol was added to the reaction system to measure the amount of free chlorine generated in the system.

[0069] PMS concentration according to the formula ; PMS absorbance ; Free chlorine absorbance ; Free chlorine concentration ; in The unit is mmol / L, The unit is µmol / L, and the amount of free chlorine generated in the sample can be calculated.

[0070] The experimental conditions remain unchanged, Fe 3 C-BC replaced by Fe 3 C for comparison, Fe 3 C and Fe 3 Mechanism of C-BC activation of persulfate / chloride ions. Blank and parallel control experiments were set up for all experiments. 3 C / Persulfate / Chloride and Fe 3 The reaction mechanism of C-BC / persulfate / chloride ion system is as follows Figure 8 As shown in Figure a, where a is the EPR spectrum of hydroxyl radicals captured, and b is the free chlorine generation diagram. The results show that: using DMPO as a capture agent, the oxygen-containing free radicals generated in the system are captured and tested by EPR, and the results are shown in Figure a. At 5min, 10min and 15min, / Persulfate / Fe 3 C system has no characteristic peak signal, but Fe 3 C replaced by Fe 3 After C-BC, DMPO- • The characteristic peak signal of OH indicates • OH is one of the main reactive oxygen species that cause endocrine disruption and has a significant impact on Fe 3 Modification of C can help • OH is produced. In addition, as shown in Figure b, with Fe 3 C and Fe 3 After C-BC activated persulfate, free chlorine was generated at 20 min, which were 13.1 μmol / L and 56.2 μmol / L, respectively. 3 The promoting effect of C-BC on the generation of free chlorine is Fe 3 C. After adding methanol to quench the oxygen-containing free radicals generated in the system, Fe 3The free chlorine generation of the C-BC / persulfate / chloride system was still 48.44 μmol / L. Endocrine disruptors such as 17β-estradiol can be effectively degraded by free radicals and free chlorine oxidation. These results show that in the presence of Fe 3 In the C-BC / persulfate / chloride ion system, • OH and free chlorine can be continuously generated, thus efficiently repairing high-salinity organic wastewater rich in endocrine disruptors. Using the chloride ions in the wastewater and activating persulfate with iron carbide composite biochar nanomaterials can significantly improve the performance of free radical and free chlorine generation pathways, and synergize free radical and non-free radical pathways, thereby improving the application prospects of iron carbide nanocomposite materials to activate persulfate to treat high-salinity pharmaceutical and chemical organic wastewater.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing iron carbide composite straw carbon nanomaterial, characterized in that: The following steps are included: 1) mixing anhydrous ferric chloride solution, glucose solution and melamine solution to obtain a mixed solution; 2) The mixed liquid and the straw powder are stirred and mixed, and then wet-milled. The wet-milled product is separated and then dried to obtain a solid; 3) Sintering the solid in a nitrogen atmosphere to obtain iron carbide composite straw carbon nanomaterials.

2. The method for preparing the iron carbide composite straw carbon nanomaterial according to claim 1, characterized in that: Step 1) the mass ratio of anhydrous ferric chloride in the anhydrous ferric chloride solution, glucose in the glucose solution, and melamine in the melamine solution is 2.7-3.3:2.7-3.3:1.8-2.2; In the anhydrous ferric chloride solution, the mass volume ratio of anhydrous ferric chloride to the solvent is 2.7~3.3g:35~45mL; in the glucose solution, the mass volume ratio of glucose to the solvent is 2.7~3.3g:55~65mL; ​​in the melamine solution, the mass volume ratio of melamine to the solvent is 1.8~2.2g:90~110mL.

3. The method for preparing the iron carbide composite straw carbon nanomaterial according to claim 1 or 2, characterized in that: The solvents in the anhydrous ferric chloride solution, the glucose solution and the melamine solution are all mixed solutions of anhydrous ethanol and water; in the anhydrous ferric chloride solution, the volume ratio of anhydrous ethanol to water is 0.8~1.2:0.8~1.2; in the glucose solution, the volume ratio of anhydrous ethanol to water is 1.7~2.3:1; in the melamine solution, the volume ratio of anhydrous ethanol to water is 0.8~1.2:0.8~1.2; Step 1) The mixing temperature is 55-65° C. and the mixing time is 25-35 min.

4. The method for preparing the iron carbide composite straw carbon nanomaterial according to claim 3, characterized in that: The mass ratio of the straw powder in step 2) to the anhydrous ferric chloride in the anhydrous ferric chloride solution in step 1) is 0.45-0.55:2.7-3.3; the particle size of the straw powder is ≤200 mesh.

5. The method for preparing the iron carbide composite straw carbon nanomaterial according to claim 3, characterized in that: Step 2) the stirring and mixing temperature is 55-65°C, and the stirring and mixing time is 1-2h; The wet grinding speed is 550-650 rpm, the wet grinding time is 2.5-3.5 h, and the wet grinding medium is grinding beads with a particle size of 2 mm; The drying temperature is 170-190° C., and the drying time is 10-14 hours.

6. The method for preparing the iron carbide composite straw carbon nanomaterial according to claim 4 or 5, characterized in that: Step 3) The sintering temperature is 750-850°C, the sintering time is 2.5-3.5h; the heating rate to the sintering temperature is 3-7°C / min.

7. The iron carbide composite straw charcoal nanomaterial prepared by the method for preparing the iron carbide composite straw charcoal nanomaterial according to any one of claims 1 to 6.

8. Use of the iron carbide composite straw carbon nanomaterial according to claim 7 in activating persulfate to degrade new pollutants.

9. The use according to claim 8, characterized in that: The iron carbide composite straw carbon nanomaterial, new pollutant solution, chloride ion solution and water are mixed and shaken for adsorption, and then a persulfate solution is added for reaction; The mass volume ratio of iron carbide composite straw carbon nanomaterials and new pollutant solution is 9~11mg:4~6mL; the volume ratio of new pollutant solution, chloride ion solution, water and persulfate solution is 4~6:0.4~0.6:42~45:0.8~1.

2.

10. The use according to claim 8 or 9, characterized in that: New pollutants include endocrine disruptors and PPCPs; the concentration of the new pollutant solution is 45~55μmol / L, the concentration of the chloride ion solution is 0.8~1.2mol / L, and the concentration of the persulfate solution is 45~55mmol / L; the pH value of the reaction is 6~6.4.

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