Method for preparing ozone catalyst by recycling iron oxide scale waste residue and application thereof

Abstract

The application discloses a method for preparing an ozone catalyst by using iron oxide scale waste residues as raw materials and application thereof. By using the iron oxide scale waste residues as the ozone catalyst, various organic pollutants in water can be efficiently degraded, and the method has good industrial application value. It is found through experiments that the IOS waste residues without any treatment can be directly used as the ozone catalyst, or the IOS waste residues can be treated by means of bagging, ball milling and briquetting, urea doping and the like, and high-efficiency O3 catalysts can be obtained, the catalysts can efficiently catalyze low-concentration O3, and the effective degradation of high-concentration tetracycline in water can be realized within 12 min, and the degradation rate is 90%. The iron oxide scale block and the IOS waste residues doped with urea have the best activity, good stability and easy recycling. The above results show that the solid waste, the iron oxide scale, which is inevitably produced in the steel production process, is used as the high-efficiency catalyst of O3, the problem of resource utilization of the iron oxide scale waste residues is properly solved, and a kind of ozone water treatment technology with good industrial application prospect is developed.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of catalyst preparation, in particular to a preparation method of an iron oxide scale catalyst capable of catalyzing efficient degradation of organic pollutants by ozone. BACKGROUND

[0002] The comprehensive utilization of solid waste in the steel industry is an important part of the strategic emerging industry of energy conservation and environmental protection. The solid waste in the steel industry mainly includes: rock stripping, tailings, steel slag, iron oxide scale and power plant fly ash and other hazardous solid waste. At present, the comprehensive utilization rate of solid waste in the steel industry is low, especially the utilization rate of steel slag is less than 30%. About 0.3-0.5 tons of iron oxide scale waste slag are produced per ton of steel. According to the total crude steel output of 10.13 million tons in China in 2022, the iron oxide scale waste slag of the steel enterprises in China is more than 30 million tons. If the solid waste is not utilized in time, it will be difficult to handle in the later period, and will also occupy land and pollute the environment.

[0003] Iron oxide scale (IOS) is a layer of metal oxide adhering to the surface of metal formed when the metal is heated, heat treated or processed in a hot state. The composition and structure of the iron oxide scale differ due to the composition of the metal, the surface temperature, the heating and cooling system, the oxygen content of the surrounding medium and other factors. From the structure of the iron oxide scale, when the finishing temperature is between 700 DEG C and 900 DEG C, the iron oxide scale formed contains 80% to 90% FeO and 10% to 20% Fe3O4. When the temperature is higher than 900 DEG C and there is more oxidation and oxidizing gas, iron will be rapidly oxidized, Fe3O4 can be rapidly formed at high temperature, and a layer of Fe2O3 alone can be formed on the surface of the iron scale. When the temperature is lower than 570 DEG C, the iron oxide scale is composed of Fe3O4, and a very thin layer of Fe2O3 covers the surface. For example, the finishing temperature of hot-rolled carbon structural steel is generally controlled at about 870 DEG C, and the surrounding medium contains a large amount of oxygen, and then the cooling speed is relatively fast, so the iron oxide scale generally has a three-layer structure: ① a layer of ferrite (FeO and Fe3O4 solid solution) on the surface of the steel; ② a layer of Fe3O4 on the upper layer; ③ the uppermost layer is Fe2O3.

[0004] Catalytic ozonation has gained popularity in advanced oxidation processes (AOPs) and is a promising water treatment technology for the degradation of toxic organic pollutants in water. Homogeneous catalytic ozonation, which catalyzes the degradation of pollutants by adding metal ions to ozone, can produce secondary pollutants; heterogeneous catalytic ozonation uses metals, metal oxides and carbon materials as solid catalysts to overcome this shortcoming. Some scholars believe that the catalytic active center of metal oxides is generally the surface hydroxyl group. The surface of the metal oxide catalyst entering the solution will coordinate with water molecules, prompting the water molecules to dissociate to form surface hydroxyl groups. The presence of surface hydroxyl groups can promote the dissociation of ozone molecules and improve catalytic efficiency. Wang et al. summarized the mechanism of metal oxide catalytic ozonation as follows:

[0005] O3+Me-OH2 + →Me-OH + +HO3 (1)

[0006] 2O3+Me-OH→Me-O2 - +HO3+O2 (2)

[0007] Me-OH + +H2O→Me-OH2 + +OH (3)

[0008] Me-O2 - +O3+H2O→Me-OH+O2+HO3 (4)

[0009] HO3→OH+O2 (5)

[0010] First, the dissolved ozone molecules are transferred from the liquid to the surface of the catalyst, combined with the surface groups of the catalyst to initiate free radical reactions, and produce active substances such as hydroxyl radicals to directly attack organic pollutants to achieve degradation. According to the survey, ferric oxide can be used as an active catalyst for catalytic ozonation. For example, Professor Hu Chun of the Ecological Environment Research Center of the Chinese Academy of Sciences developed a mesoporous alumina loaded with magnetic ferric oxide nanomaterials for heterogeneous catalytic ozonation. Li Xiaqin of Guangzhou Sunny Environmental Protection Technology Co., Ltd. developed a magnetic iron oxide powder ozone catalyst. Zeng Fuhe of Hunan 352 Environmental Protection Technology Co., Ltd. developed a manganese-cerium composite oxide@magnesium-aluminum composite oxide@alumina@ferric oxide catalyst. However, these synthetic catalysts either have complex preparation processes, need to add one or more active materials, or have cumbersome recovery methods that require additional magnetic fields, or have a large amount of catalyst usage. Therefore, further research is needed to develop a catalyst that is simple to prepare, easy to recover and can efficiently catalyze ozone. SUMMARY

[0011] In order to solve the above technical problems, the application provides a simple method for preparing iron oxide scale for efficiently catalyzing ozone to degrade organic pollutants in water.

[0012] The method for preparing the ozone catalyst by using the iron oxide scale waste residue as raw material comprises the following steps: mixing the iron oxide scale waste residue with hot polyvinyl alcohol, grinding, obtaining iron oxide scale powder, pressing the iron oxide scale powder into blocks, and calcining under inert atmosphere to obtain the ozone catalyst.

[0013] The iron oxide scale is from steel plant waste residue, and comprises 40-50% of Fe3O4, 5-10% of Fe2O3, 30-40% of FeO and other impurities.

[0014] The mass ratio of the iron oxide scale waste residue and polyvinyl alcohol is 20-30:1, the grinding speed is 200-400 r / min, and the grinding time is 3-5 h.

[0015] Further, the mass ratio of the iron oxide scale and polyvinyl alcohol is 20-30:1, the mass ratio of polyvinyl alcohol and water is 1:10-15, the polyvinyl alcohol needs to be kept for 20-30 min after being heated and boiled, and then the polyvinyl alcohol is uniformly mixed with the iron oxide scale. Because the iron oxide scale is thin and brittle, it cannot be directly pressed into blocks, so polyvinyl alcohol is added as a binder.

[0016] In some technical solutions, the polyvinyl alcohol has certain viscosity when being heated to a boiling state;

[0017] The hot polyvinyl alcohol is added dropwise into the iron oxide scale, and a ball mill is used for grinding into powder, and then the powder is passed through a 200-mesh sieve.

[0018] The wet grinding is performed by using a ball mill, so that the particle size of the ground iron oxide scale is smaller, and then the dry grinding is performed by using a ball mill, so that the iron oxide scale powder is obtained, and the iron oxide scale powder is more easily taken out.

[0019] After grinding, the sieve is passed, and the iron oxide scale powder with a particle size of less than or equal to 75 microns is collected, so as to remove impurities and reduce the particle size of the iron oxide scale powder, and the iron oxide scale powder is more easily pressed into blocks.

[0020] Another technical solution of the application is that the obtained iron oxide scale powder is mixed with urea at a mass ratio of 1:1-2, oscillated, and then filtered to obtain urea-doped iron oxide scale powder, and the mixed product is obtained by drying at 50-70 DEG C for 1-3 h.

[0021] The obtained iron oxide scale powder or mixed product is pressed under a pressure of 20000-30000 N for 20-40 s, so that the iron oxide scale powder is pressed into blocks.

[0022] The calcination temperature is 300-500 DEG C, the calcination rate is 8-15 DEG C / min, and the calcination time is 1-3 h.

[0023] The furnace is a tube furnace or a muffle furnace, the gas is nitrogen or air, and the sample of the briquette is heated to remove polyvinyl alcohol and make the iron block more solid.

[0024] In the present application, the mill scale powder is directly ground without treatment, and is obtained after passing through a 200-mesh screen.

[0025] For the above method, the present application also provides a method for recycling and preparing an ozone catalyst from mill scale waste.

[0026] The present application provides the application of the above-prepared ozone catalyst prepared from mill scale waste in catalyzing O3 to remove pollutants in water.

[0027] The pollutants include any one of tetracycline, sulfamethoxazole, atrazine and bisphenol A.

[0028] The mill scale pretreated in different ways is placed in water containing a certain concentration of organic pollutants, and a certain concentration of ozone (0.5-1.5 mg / L) is passed through, so that the removal rate of the organic pollutants can reach 55-76% within 2 minutes, and the removal rate of the organic pollutants can reach 89-91% within 12 minutes.

[0029] The present application provides the application of the above-prepared ozone catalyst prepared from mill scale waste in catalyzing O3 to remove pollutants in water.

[0030] Further, the mill scale pretreated in different ways includes powdered mill scale, briquetted mill scale, untreated mill scale wrapped in a filter paper bag, untreated mill scale wrapped in an activated carbon bag, untreated mill scale wrapped in a plastic mesh bag, urea-doped mill scale, hydrochloric acid-washed mill scale and hydrogen peroxide-washed mill scale, and the organic pollutants include tetracycline antibiotics, sulfonamide antibiotics, triazine pesticides and estrogen drugs.

[0031] In the present application, the mill scale preparation process is simple, the conditions are controllable, the process parameters are easy to adjust, and the process is green and environmentally friendly. Moreover, the mill scale raw material is cheap, widely available, green and safe, and is expected to be used on a large scale to catalyze ozone to remove organic pollutants in water. By briquetting the mill scale, the mill scale has excellent catalytic O3 performance, and the briquetted mill scale is convenient to recycle, so that the degradation of organic pollutants can be realized more efficiently and energy-savingly. Attached Figure Description

[0032] Figure 1 This is a process flow diagram illustrating different treatment methods for iron oxide scale and its application in ozone catalysis.

[0033] Figure 2 The nitrogen-calcined IOS prepared in Example 2 b SEM images before and after the reaction.

[0034] Figure 3 IOS and nitrogen calcination of IOS b XRD and XRF plots.

[0035] Figure 4 For example, IOS in Examples 4-5 a Nitrogen calcination IOS b The degradation kinetics of TC by filter bags of different materials.

[0036] Figure 5 The degradation kinetics of TC by O3 catalyzed by different amounts of iron oxide scale in Example 6 are shown.

[0037] Figure 6 This describes the kinetics of IOS-catalyzed ozone degradation of TC at different pH levels in Example 7.

[0038] Figure 7 The degradation kinetics of atrazine (ATZ), bisphenol A (BPA), and sulfamethoxazole (SMX) in the O3 / IOS system of Example 8 are presented.

[0039] Figure 8 For example, IOS in Example 9 b Seven cycles of the experiment.

[0040] Figure 9 The IOS obtained by calcination using air and nitrogen in Example 10, respectively. b Degradation kinetics of TC.

[0041] Figure 10 Fe3O4 and IOS in Example 10 b Kinetics of catalytic ozone degradation of TC.

[0042] Figure 11 The degradation kinetics of TC by IOS modified by different methods in Example 11 are shown.

[0043] The abbreviations in the above attached diagram have the following meanings:

[0044] IOS stands for untreated iron oxide scale;

[0045] iOS a Represents powdered iron oxide scale;

[0046] IOS b indicates the oxide scale after calcination in the form of a lump;

[0047] Filter paper bag IOS indicates untreated oxide scale wrapped with a filter paper bag;

[0048] Activated carbon bag IOS indicates untreated oxide scale wrapped with an activated carbon bag;

[0049] Plastic mesh IOS indicates untreated oxide scale wrapped with a plastic mesh;

[0050] IOS-50 indicates 50 mg of untreated oxide scale;

[0051] IOS-100 indicates 100 mg of untreated oxide scale;

[0052] IOS-200 indicates 200 mg of untreated oxide scale;

[0053] IOS-400 indicates 400 mg of untreated oxide scale. DETAILED DESCRIPTION

[0054] The oxide scale is from waste material of a steel plant in Liaocheng, Shandong. During steel forging and hot rolling hot working, a large amount of oxide scale is often formed due to the reaction of steel and oxygen in the air. The oxide scale can be divided into primary oxide scale, secondary oxide scale, tertiary oxide scale and red oxide scale. (1) The primary oxide scale is gray-black scale layer, which is in the form of flake covering the surface of the steel plate. The main component of the scale layer is composed of magnetite (Fe304). (2) The secondary oxide scale is red scale layer, which is in the form of obvious long strip, indentation, and is distributed in the form of band along the rolling direction. The main component of the scale layer is composed of microparticles of wustite (FeO), hematite (Fe203) and the like. (3) The tertiary oxide scale defect is visible to the naked eye: black-brown, small boat-shaped. It is relatively dense, fine and sand-like distributed on the surface of the defective steel strip. After pickling, it leaves pinhole-shaped small pits of different depths on the surface of the steel strip at the defect site, which is invisible on the surface of the normal hot-rolled steel strip. (4) The red oxide scale is divided into two types: one is unevenly distributed in the width direction of the plate, mainly in the middle, and is also uneven in the length direction of the steel plate, with slightly lighter individual parts. This red oxide scale is relatively thick and can be blown away by high-pressure air during straightening. The residual red color is easy to wipe off. This red oxide scale is more appropriate to be called red rust. The other type of red oxide scale is evenly distributed along the width of the plate, with slightly heavier 100 mm inside the edge and heavier outside than inside. This red oxide scale is relatively thin and not easy to wipe off. The thicker the steel plate, the redder the color. This type of red oxide scale also exists in other steel types and has a certain universality.

[0055] Example 1

[0056] The mill scale is from a steel plant, and the untreated mill scale sample is IOS (see Figure 1 a) 100 g of IOS is weighed and mixed with 4 g of hot-melt polyvinyl alcohol, ground and sieved through a 0.075 mm sieve to obtain a mill scale powder sample IOS a .

[0057] Example 2

[0058] 4 g of the mill scale powder sample is weighed and placed in a powder briquetting machine, and pressed for 30 s under a pressure of 20,000 N to form a briquette (cuboid, size: 2.5 cm x 0.8 cm x 0.6 cm). The formed mill scale briquette is placed in a crucible and calcined in a muffle furnace under an air atmosphere, with a temperature rise rate of 10 ℃ / min, to a temperature of 400 ℃, and run for 2 h. After natural cooling, the sample is taken out, and the obtained sample is air calcined IOS b .

[0059] Example 3

[0060] 4 g of the mill scale powder sample is weighed and placed in a powder briquetting machine, and pressed for 30 s under a pressure of 20,000 N to form a briquette (cuboid, size: 2.5 cm x 0.8 cm x 0.6 cm). The formed mill scale briquette is placed in a crucible and calcined in a muffle furnace under an air atmosphere, with a temperature rise rate of 10 ℃ / min, to a temperature of 400 ℃, and run for 2 h. After natural cooling, the sample is taken out, and the obtained sample is air calcined IOS b .

[0061] In the present application, not only powder and block mill scales are prepared, but also urea-doped mill scales with high catalytic performance are prepared. The mill scales before and after heating are physically characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence spectrometry (XRF), and the performance of the mill scales in catalyzing O3 is studied by a TC degradation experiment. Figure 2 The SEM results show that there is little difference between the IOS b before and after the reaction, and the surface of the mill scale after the reaction is smoother, and the fine particles on the surface disappear, which indicates that the IOS b has excellent stability. Figure 3 The XRD results of (a) show that the main components of the untreated mill scale are magnetite and some other iron oxides, and after calcination, elemental iron is newly generated in addition to the magnetite and some other iron oxides. Figure 3 The XRF results of (b) show that the iron element accounts for 95.94% of the total elements in the untreated mill scale, and the proportion of the iron element in the calcined mill scale increases slightly to 97.46%.

[0062] Example 4

[0063] IOS prepared in Example 1 a and nitrogen calcined IOS prepared in Example 2 b Kinetics of removal of TC by mill scale a The sample was placed in a quartz glass reactor, 75 ml of TC (200 mg / L) was added, followed by 225 ml of deionized water, and O3 was introduced, with the O3 concentration controlled at 0.5 mg / L to 1.5 mg / L. 2.5 ml of sample was taken at 0, 0.5, 1, 2, 4, 8, and 12 min, and the concentration of TC was detected at λ max = 360 nm using a UV spectrophotometer. b Kinetics of removal of TC was operated as above. Figure 4 The results of the TC degradation experiment of the nitrogen calcined IOS b showed that it had good catalytic O3 performance, with a removal rate of TC of 76.24% within 2 min, and a degradation rate of 0.739 min -1 , which was 2.19 times that of the removal rate of ozone alone.

[0064] Example 5

[0065] Kinetics of removal of TC by filter bags of different materials Figure 1 b), was placed in a quartz glass reactor, 75 ml of TC (200 mg / L) was added, followed by 225 ml of deionized water, and O3 was introduced, with the O3 concentration controlled at 0.5 mg / L to 1.5 mg / L. 2.5 ml of sample was taken at 0, 0.5, 1, 2, 4, 8, and 12 min, and the concentration of TC was detected at λ max = 360 nm using a UV spectrophotometer.

[0066] Example 6

[0067] Kinetics of degradation of TC by O3 catalyzed by different amounts of mill scale Figure 1 a) was placed in a quartz glass reactor, 75 ml of TC (200 mg / L) was added, followed by 225 ml of deionized water, and O3 was introduced, with the O3 concentration controlled at 0.5 mg / L to 1.5 mg / L. 2.5 ml of sample was taken at 0, 0.5, 1, 2, 4, 8, and 12 min, and the concentration of TC was detected at λmax = 360 nm.

[0068] Figure 5 The results of the experiment of catalyzing O3 to degrade TC by different amounts of IOS showed that the degradation rate of TC increased (0.217 min -1 → 0.767 min -1 ) with the increase of the amount of IOS (0 mg → 400 mg). This showed that IOS could well activate O3 to accelerate the degradation of TC.

[0069] Example 7

[0070] The operation steps of the degradation kinetics of TC by different pH values were as follows: 200 mg of IOS (see Figure 1 a) was placed in a quartz reactor, 75 ml of TC (200 mg / L) and 200 ml of deionized water were added in a 500 ml beaker, the pH value of the solution was adjusted to 3 by using NaOH solution and HCl solution, the solution was diluted to 300 ml, and then poured into the quartz reactor, O3 (concentration of 0.5 mg / L to 1.5 mg / L) was introduced, 2.5 ml of sample was taken at 0, 0.5, 1, 2, 4, 8 and 12 min, and the concentration of TC was detected at λ max = 360 nm by using an ultraviolet spectrophotometer. The operation method at pH = 5, 7 and 9 was the same as above. Figure 6 The results of the degradation kinetics experiment of TC by different pH values showed that the removal rate of TC was only 19.5% within 2 min at pH = 3, and the removal rate of TC reached 70.15% at pH = 9. This showed that acidic conditions were not conducive to the catalysis of IOS to degrade TC by O3, and alkaline conditions were conducive to the degradation of TC.

[0071] Example 8

[0072] The operation steps of the degradation kinetics of different pollutants by O3 / IOS system were as follows: 200 mg of IOS (see Figure 1 a) was placed in a quartz reactor, 300 ml of 1 mg / L ATZ, 12 mg / L BPA and 10 mg / L SMX were added respectively, O3 (concentration of 0.5 mg / L to 1.5 mg / L) was introduced, 2.5 ml of sample was taken at 0, 0.5, 1, 2, 4, 8 and 12 min, and then filtered by using a 0.22 μm filter membrane, and the concentrations of residual ATZ, BPA and SMX were determined at λ = 220 nm, 278 nm and 257 nm respectively by using an agilent high performance liquid chromatography (HPLC) system. Figure 7The degradation kinetics results of different pollutants by O3 / IOS system show that the removal rates of ATZ, BPA and SMX by O3 / IOS system reach 73.12%~93.75% within 4 min, which indicates that the O3 system catalyzed by iron oxide scale has the ability to efficiently degrade various pollutants.

[0073] Example 9

[0074] The operation steps of the circulation experiment are as follows: an IOS sample calcined in nitrogen is taken and placed in a quartz reactor, 75 ml of TC (200 mg / L) is added, then 225 ml of deionized water is added, O3 is introduced, the O3 concentration is controlled at 0.5 mg / L~1.5 mg / L, and 2.5 ml of sample is taken at 0, 0.5, 1, 2, 4, 8, and 12 min, respectively. After the reaction is completed, the remaining reaction solution is poured out, 75 ml of TC (200 mg / L) and 225 ml of deionized water are added again, O3 is introduced for reaction, and the above operation is repeated 7 times. The TC concentration is detected at λ b =360 nm by using an ultraviolet spectrophotometer. max Figure 8 The circulation experiment of the IOS b shows that the IOS b has good stability, and the degradation rate of TC is maintained at above 82.02% within 4 min. The photos show that the IOS b still has no damage after being used for 7 times, which is conducive to multiple use in industry.

[0075] Example 10

[0076] The operation steps of the degradation kinetics of TC by using air IOS b and nitrogen calcined IOS b are as follows: the air IOS and nitrogen calcined IOS are respectively placed in a quartz reactor, 300 ml of 50 mg / L TC solution is added, O3 (the concentration is 0.5 mg / L~1.5 mg / L) is introduced, 2.5 ml of sample is taken at 0, 0.5, 1, 2, 4, 8, and 12 min, respectively, and the TC concentration is detected at λ max =360 nm by using an ultraviolet spectrophotometer. Figure 9 The results of the TC degradation experiment by using the IOS b calcined in different atmospheres show that the removal rates of TC can reach 90% within 12 min. This indicates that whether the IOS is calcined in air or in inert gas nitrogen, it has high performance of catalyzing O3.

[0077] Example 11

[0078] ​2.07 g FeCl3·6H2O and 2.78 g FeSO4·7H2O were dissolved in 100 mL of distilled water, respectively. 42 mL of FeCl3 solution and FeSO4 solution were measured using a graduated cylinder and transferred to 250 mL beakers. The mixture was stirred until fully homogeneous. HCl or NaOH was slowly added dropwise while stirring at room temperature to adjust the pH of the mixed solution to 11.5. The reaction was carried out at a constant temperature of 60 °C with stirring for 1 h. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. It was washed alternately with distilled water and anhydrous ethanol until neutral and then vacuum dried at 60 °C for 12 h. The resulting sample was Fe3O4.

[0079] Example 12

[0080] Kinetic operation steps of Fe3O4 catalytic ozone degradation of TC: Weigh 200 mg of the Fe3O4 sample prepared in Example 11 and place it in a quartz reactor. Add 300 ml of 50 mg / L TC solution and purge with O3 (concentration 0.5 mg / L to 1.5 mg / L). Take 2.5 ml of sample at 0, 0.5, 1, 2, 4, 8, and 12 min respectively. Use a UV spectrophotometer to measure the TC at λ. max TC concentration was detected at 360 nm. Figure 10 The degradation kinetics of total nitrogen (TC) were compared using iron oxide (Fe3O4) and iron oxide catalyzed ozone, respectively. The results showed that the degradation efficiencies of both iron oxide and iron oxide catalyzed ozone on TC within 2 minutes were 0.564 min and 0.564 min, respectively. -1 and 0.739min -1 This indicates that iron oxide scale has a more efficient ozone catalytic performance than iron oxide.

[0081] Example 13

[0082] Preparation methods of iron oxide scale modified by different methods: 1g of iron oxide scale powder and 1g of urea are mixed in pure water, shaken repeatedly in a shaking box for 30min, filtered by a vacuum pump, placed in an oven and dried at 60℃ for 2h to prepare urea-doped IOS (urea / IOS).

[0083] IOS was calcined by washing with nitrogen gas using 3 mol / L hydrochloric acid. b The mixture is rinsed 2-3 times, then washed 2-3 times with pure water, and then dried in an oven at 60°C for 2 hours to obtain pickled iron oxide scale (HCl / IOS).

[0084] IOS was calcined by purging with nitrogen using 30% H2O2. b Rinse 2-3 times with pure water, then dry in an oven at 60℃ for 2 hours to obtain hydrogen peroxide-washed iron oxide scale (H2O2 / IOS).

[0085] Example 14

[0086] Kinetical operation procedure of different modified IOS to degrade TC: 200 mg of different modified IOS samples prepared in Example 13 (blocky directly used) were placed in a quartz reactor, 300 ml of 50 mg / L TC solution was added, O3 (concentration of 0.5 mg / L-1.5 mg / L) was introduced, 2.5 ml samples were taken at 0, 0.5, 1, 2, 4, 8, 12 min, and the concentration of TC was detected at λ = 360 nm using a UV spectrophotometer. max Figure 11 The degradation kinetics of TC by different modified IOS was shown, and the results showed that the iron oxide scale washed with hydrochloric acid and the iron oxide scale washed with hydrogen peroxide both reduced the performance of the iron oxide scale in catalyzing ozone, while the iron oxide scale doped with urea could better improve the performance of the iron oxide scale in catalyzing ozone.​

Claims

1. The application of the ozone catalyst prepared by recycling the mill scale waste as raw material in the catalytic removal of pollutants in water body by O3, characterized in that, The mill grinds the mixed iron oxide scale waste residue and hot-soluble polyvinyl alcohol to obtain iron oxide scale powder, presses the iron oxide scale powder into a block, and calcines the block in an air or nitrogen atmosphere to obtain an ozone catalyst; The iron oxide scale is from steel plant waste residue, and includes 40-50% Fe3O4, 5-10% Fe2O3, 30-40% FeO, and other impurities; The iron oxide scale powder is pressed into a block under a pressure of 20,000-30,000 N for 20-40 s; The calcination temperature is 300-500 ℃, the calcination heating rate is 8-15 ℃ / min, and the calcination time is 1-3 h.

2. Use according to claim 1, characterized in that, The mass ratio of the iron oxide scale waste residue to the polyvinyl alcohol is 20-30:1, the grinding speed is 200-400 r / min, and the grinding time is 3-5 h.

3. Use according to claim 1, characterized in that, The pollutants include any one of tetracycline, sulfamethoxazole, atrazine, and bisphenol A.

4. The application of the ozone catalyst prepared by recycling the mill scale waste as raw material in the catalytic removal of pollutants in water bodies by O3, characterized in that, The mill grinds the mixed iron oxide scale waste residue and hot-soluble polyvinyl alcohol to obtain iron oxide scale powder, mixes the obtained iron oxide scale powder with urea at a mass ratio of 1:1-2, oscillates, and then performs suction filtration to obtain urea-doped iron oxide scale powder, dries the urea-doped iron oxide scale powder at 50-70 ℃ for 1-3 h to obtain a mixed product, presses the mixed product into a block, and calcines the block in an air or nitrogen atmosphere to obtain an ozone catalyst; The iron oxide scale is from steel plant waste residue, and includes 40-50% Fe3O4, 5-10% Fe2O3, 30-40% FeO, and other impurities; The mixed product is pressed into a block under a pressure of 20,000-30,000 N for 20-40 s; The calcination temperature is 300-500 ℃, the calcination heating rate is 8-15 ℃ / min, and the calcination time is 1-3 h.

Images