Catalyst based on ball-milling degradation residue and preparation method and application thereof

Abstract

The application provides a catalyst based on ball-milling degradation residues and a preparation method and application thereof. The catalyst comprises the following steps: based on the optimal condition of removing hexachloroethane by mechanical grinding, recycling the magnetic tailings; taking natural bentonite as raw material, carrying out roasting modification, and then loading the grinding agent on the modified bentonite by a chemical precipitation method. Compared with the traditional grinding agent treatment method, the process of the application is simple, the condition is mild, and resource waste is avoided; meanwhile, the material has good removal effect on simulated wastewater and good reusability. The process of the application has wide application range, the main raw materials are all the remaining materials of mechanical grinding, other raw materials are simple to obtain, the resource waste is avoided, the pollutants in water are removed, and the application is an environmental protection and efficient resource recycling method.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of waste harmless treatment and material recycling, and provides a method for recycling residual material by mechanical grinding, in particular to a catalyst based on ball-milling degradation of residual material, and a preparation method and application thereof. BACKGROUND

[0002] In recent years, compared with traditional processes, mechanical chemistry has attracted much attention in the treatment of organic pollutants due to its safety in operation, simple reaction process, high efficiency, wide application range and small potential secondary pollution. In the 1990s, the idea of using mechanical chemistry to treat organic pollutants was first proposed. Chlorobenzene, DDT, PCB and alkali metal and their oxides were mixed into a ball mill tank, and after ball milling for 12 h, the organic chlorides were completely degraded. Since then, mechanical chemistry has been considered as a completely feasible treatment technology for removing organic pollutants.

[0003] Generally, after being treated by a high-energy ball mill, the organic pollutants reach the effect of harmless treatment, and the grinding agent and mineralized products are obtained after the reaction, and the obtained residual material can be put into a safe landfill site after incineration. However, direct landfill of a large amount of metal elements in the residual material will cause waste of resources, and there are few known studies on recycling of residual tailings.

[0004] At present, the treatment method for the grinding agent and the mineralized product of the pollutants is mainly incineration and landfill. Such treatment methods are beneficial to environmental protection, but most of the grinding agents contain metal elements, and direct destruction after grinding can easily cause waste of resources. Fe3O4 has a unique cubic inverse spinel structure, and oxygen ions form a tightly packed sublattice, and divalent iron ions and trivalent iron ions are interspersed in the interstitial positions, so that electrons can be rapidly transferred between ions. Therefore, the cation sites on Fe3O4 are a kind of multifunctional redox active sites. In recent years, some scholars have applied Fe / Fe3O4 to mechanical chemistry as a ball milling agent to degrade pollutants. At present, there are few studies on recycling of residual material of Fe / Fe3O4 grinding agent, and literature search on prior art has not found similar inventions.

[0005] Bentonite is an excellent cationic exchange material with low cost and easy availability, and has a broad application space in water treatment. The natural bentonite is modified by calcination to remove impurities, and then a proper amount of grinding agent is loaded thereon by a chemical coprecipitation method to construct a Fenton system for removing pollutants, which has great potential. SUMMARY

[0006] In order to solve the above technical problems, the present application provides a method for recycling residual material by mechanical grinding. In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] The present application provides a catalyst based on ball-milling degradation residue, which is prepared as follows:

[0008] (1) dry raw bentonite is passed through a 100-mesh sieve, calcined in a muffle furnace at 400-500°C (preferably 450°C) for 2h, and activated at 105-110°C for 1h to obtain modified bentonite;

[0009] (2) the modified bentonite and the ball-milling degradation residue of step (1) are uniformly dispersed in an aqueous ethanol solution with a volume fraction of 55%-65% (preferably 60%), stirred in a water bath at 17-23°C for 3.5-4.5h (preferably stirred in a water bath at 20°C for 4h), and aged for 22-26h (preferably 24h) after standing, and the obtained reaction solution is treated to obtain the catalyst based on ball-milling degradation residue; the mass ratio of the modified bentonite to the ball-milling degradation residue is 10:1-6 (preferably 10:5);

[0010] The ball-milling degradation residue is a magnetic material after iron powder and ferroferric oxide degrade hexachloroethane under ball-milling conditions.

[0011] In an embodiment of the present application, the ball-milling degradation residue is obtained as follows:

[0012] Hexachloroethane, iron powder, and ferroferric oxide are mixed and subjected to ball-milling degradation at room temperature (25±2) °C for 1.8-2.2h (preferably 2h), and after cooling to room temperature, the obtained mixture is subjected to solid-liquid separation using a magnet, and the solid adhering to the magnet is the ball-milling degradation residue; the mass ratio of the hexachloroethane, iron powder, and ferroferric oxide is 1:4-4.1:9.3-9.6 (preferably 1:4.05:9.45).

[0013] Preferably, the ball-milling degradation conditions are: ball-to-material ratio of 20:1, ball mill rotation speed of 600rpm, rotation alternately running for 30min, and total ball-milling time of 2h.

[0014] The inventors have also explored the residue of iron powder and ferroferric oxide degrading other organic substances such as hexachlorobenzene under ball-milling conditions, but the catalyst prepared from the residue has very poor catalytic effect.

[0015] Further, the volume of the aqueous ethanol solution in step (2) is 10-30mL / g (preferably 20mL / g) based on the total mass of the modified bentonite and the ball-milling degradation residue.

[0016] Further, the post-treatment in step (2) is: filtering the reaction solution, repeatedly washing with deionized water until the filtrate is neutral, drying the obtained filter cake (drying at 100-110 DEG C for 3.5-4 h, preferably drying at 100 DEG C for 4 h), grinding into powder, and passing through a 100-mesh sieve, to obtain the catalyst based on the ball-milling degradation residue.

[0017] In another aspect, the application also provides a use of the above-mentioned catalyst based on the ball-milling degradation residue in degrading organic contaminant wastewater.

[0018] In an embodiment of the application, the organic contaminant in the organic contaminant wastewater is furazolidone.

[0019] Specifically, the use is: adding the catalyst based on the ball-milling degradation residue into the organic contaminant wastewater, constructing a degradation system, adjusting the pH to 3, and degrading.

[0020] Further, in the degradation system, the concentration of the catalyst based on the ball-milling degradation residue is 1.8-2.2 g / L (preferably 2.0 g / L).

[0021] Further, the concentration of the organic contaminant in the organic contaminant wastewater is 80-120 mg / L (preferably 100 mg / L).

[0022] Preferably, the degradation system further comprises hydrogen peroxide. Further preferably, in the degradation system, the mass fraction of hydrogen peroxide is 0.25-0.35% (preferably 0.03%).

[0023] Compared with the prior art, the technical solution provided by the application has the following beneficial effects:

[0024] (1) The resource recycling method of the mechanical grinding residue provided by the application directly loads the grinding agent on bentonite which has low cost, large specific surface area and better adsorption performance, thereby reducing the cost and improving the use rate of the grinding agent.

[0025] (2) The prepared material has spherical grinding agents uniformly loaded on the surface of bentonite, and has compact texture, thereby further increasing the specific surface area of the material, increasing the active sites, and improving the adsorption potential of the material to pollutants.

[0026] (3) Due to the presence of Fe and Fe3O4 in the grinding agent, the prepared material can not only adsorb and remove furazolidone alone, but also can construct a Fenton system with hydrogen peroxide to catalyze and activate hydrogen peroxide to generate ·OH free radicals to oxidize and remove furazolidone.

[0027] (4) By loading the active ingredient on bentonite, the obtained catalyst has good stability, and the removal rate of furagin maintains at a high level after 5 times of repeated use, indicating that the material can be used for the removal of furagin wastewater stably and efficiently. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Study on the adsorption effect of different materials on furagin alone

[0029] Figure 2 SEM and EDS spectra of grinding agent (a, b) and R-B-F (c, d)

[0030] Figure 3 Effect of different materials on the removal of furagin in Fenton system

[0031] Figure 4 XRD diffraction peak spectrum of the material

[0032] Figure 5 Removal effect of R-B-F on furagin in 5 consecutive experiments

[0033] Figure 6 Effect of different materials on the removal of furagin in Fenton system

[0034] Figure 7 Study on the adsorption effect of different materials on furagin alone

[0035] Figure 8 Effect of different materials on the removal of furagin in Fenton system

[0036] Figure 9 Effect of different loading rates on the removal of furagin

[0037] Figure 10 Effect of different pH on the removal of furagin

[0038] Figure 11 Effect of different R-B-F dosages on the removal of furagin

[0039] Figure 12 Effect of different H2O2 dosages on the removal of furagin DETAILED DESCRIPTION

[0040] The catalyst of the present application is analyzed and explained in detail in the following cases. The following is only a preferred embodiment of the present application, which cannot limit the scope of the present application. Any equivalent changes and modifications made within the scope of the present application are covered by the present application. The original bentonite in the embodiment of the present application is purchased from Beijing Century Oukai Biotechnology Co., Ltd.

[0041] Preparation of grinding agent in Example 1

[0042] Into a 80 mL stainless steel ball mill pot, 0.5 g of hexachloroethane, 2.025 g of iron powder, 4.725 g of ferric oxide were added at room temperature (25±2) °C, ensuring the material ratio (iron powder plus ferric oxide to hexachloroethane) was 13.5:1, the weight of the grinding ball was 145 g, the ball-to-material ratio was 20:1, the rotation speed of the ball mill was 600 rpm, and the total ball milling time was 2 h. After the mechanical grinding was completed, the remaining material was cooled to room temperature, and the magnetic material in the remaining material was separated by a magnet. The obtained solid was the grinding agent, which was stored in a desiccator for later use.

[0043] Example 2 Preparation of calcined modified bentonite

[0044] Calcination modification of raw bentonite: A certain amount of dry raw bentonite was sieved through a 100-mesh sieve and placed in a porcelain crucible. The crucible was placed in a muffle furnace at 450 °C for 2 h, then activated at 105-110 °C for 1 h, and finally cooled to room temperature to obtain a 450 °C calcined modified bentonite, which was packaged for later use.

[0045] Example 3 Preparation of modified bentonite loaded grinding agent composite material

[0046] Preparation of modified bentonite loaded grinding agent: A 1 L volume ratio of 60:40 anhydrous ethanol-water medium was prepared. Different amounts of modified bentonite prepared according to Example 2 and grinding agent prepared according to Example 1 were weighed according to different loading rates (loading rate = grinding agent / bentonite) to prepare modified bentonite loaded grinding agent composite materials with different loading rates:

[0047] The weighed modified bentonite was placed in a round flask, 200 mL of the prepared anhydrous ethanol-water medium was added, and the mixture was dispersed uniformly for 10 min. Then the weighed grinding agent was added to the flask, and the total amount of the two was 10 g. The obtained mixture was placed in a 20 °C water bath and stirred for 4 h. After standing for 24 h, the filtrate was washed until the pH was neutral. The filtrate was placed in an oven and dried at 100 °C for 4 h. The powder was ground and sieved through a 100-mesh sieve to obtain the modified bentonite loaded grinding agent composite material. According to different loading rates, it was named R-B-F-loading rate, for example, the modified bentonite loaded grinding agent composite material with a loading rate of 50% was named R-B-F-50%.

[0048] Example 4 Adsorption performance test

[0049] The adsorption effects of the adsorbents, i.e. raw bentonite (B), calcined modified bentonite (R-B) prepared according to the method of Example 2, bentonite abrasive composite (B-F-50%) and modified bentonite abrasive composite (R-B-F-50%) prepared according to the method of Example 3, on furacilin in simulated wastewater (i.e. furacilin aqueous solution) with a concentration of 100 mg / L were detected.

[0050] wherein the raw bentonite (B) was dried through a 100-mesh sieve; the bentonite abrasive composite (B-F) was prepared according to the method of Example 3, with the only difference that the raw bentonite (B) was used instead of the calcined modified bentonite.

[0051] The test procedure was as follows: under constant temperature (25±2) °C, 200 mL of furacilin solution with a concentration of 100 mg / L was added to each of 5 beakers and labeled. The No. 1 beaker was the blank control group, and 2.0 g / L of the above adsorbent was added to the No. 2-5 beakers in turn, and the pH of the solution was adjusted to 3 using 0.1 mol / L dilute sulfuric acid solution. Then the beakers were placed in a constant temperature oscillator, and timed sampling was performed at 5 min, 10 min, 20 min, 30 min, 60 min, 120 min, 180 min and 240 min using a 10 mL syringe, and the water samples were filtered using a 0.45 μm needle filter. The experimental results are shown in Table 1. Figure 3

[0052] The concentration of furacilin in the blank group remained basically unchanged after constant temperature oscillation for 240 min, and the adsorption removal rate of furacilin by R-B modified by calcination at 450 °C was 27.29%, which was 6.43% higher than that of B. The adsorption removal rates of furacilin by B-F and R-B-F loaded with abrasive were 33.30% and 41.30% respectively, which were significantly improved. The adsorption effect was improved after the raw bentonite and the modified bentonite were loaded with abrasive, and the adsorption capacity of R-B was significantly improved. As can be seen from the SEM image Figure 2 , the morphology and structure of R-B changed after calcination modification, and the adsorption capacity was improved.

[0053] Figure 2 The image of the abrasive magnified by 50,000 times shows that the abrasive has a good dispersion, clear particle size and spherical structure, and Fe and O elements are the main components, indicating that the main components of the mechanical-chemical residual material recovered by magnetic separation are Fe and Fe3O4, without the generation of other substances. Figure 2 ​c is the image of modified bentonite loaded abrasive magnified 100,000 times. It can be seen that the spherical structure of the abrasive particles is attached to the surface of the modified bentonite, and the layered structure of the bentonite is retained, further increasing the specific surface area of the material, increasing the active sites, and improving the adsorption potential of the material to pollutants. From Figure 2 The EDS elemental spectrum of d can be seen that the Fe element occupies the dominant position, and the Si element content is low, indicating that the material is the abrasive attached to the surface of the bentonite, and is not completely wrapped or inserted into the crystal layer of the bentonite. The material in the H2O2 Fenton system, Fe 2+ Can quickly react with H2O2 to remove pollutants.

[0054] Example 5 Fenton system performance test

[0055] The abrasive was prepared by the method in Example 1; the modified bentonite (R-B) prepared according to the method of Example 2, the modified bentonite loaded abrasive composite material (R-B-F-50%) prepared according to the method of Example 3, and the raw bentonite loaded abrasive composite material (B-F-50%) were prepared according to the same process as Example 3, the only difference being that the raw bentonite (B) was replaced by the calcined modified bentonite. The removal effect in 100mg / L furazolidone simulated wastewater (i.e. furazolidone aqueous solution) was detected.

[0056] The test process is as follows: under the condition of constant temperature (25±2) ℃, 200mL of furazolidone solution with a concentration of 100mg / L was added to 4 beakers and labeled. The No. 1 beaker was the blank control group, the No. 2 beaker was added with 1mL / L of 30% H2O2 solution, and the No. 3 and No. 4 beakers were added with 2.0g / L of the above-mentioned materials (B-F, R-B-F) and 1mL / L of 30% H2O2 solution, respectively. The pH of the solutions in the No. 2, No. 3 and No. 4 beakers was adjusted to 3 with 0.1mol / L dilute sulfuric acid solution, and then the beakers were placed in a constant temperature oscillator. At 5min, 10min, 20min, 30min, 60min, 120min, 180min and 240min, 10mL of sample was taken with a syringe, and the water sample was filtered with a 0.45μm needle filter. The experimental results are shown in Figure 3 .

[0057] The above experiments show that furacilin is basically not removed when placed alone, and the removal rate is not greatly improved when H2O2 is added alone. Under the same preparation conditions and test conditions, the removal rate of furacilin by the Fenton system constructed by adding B-F and H2O2 is 67.83% at 240 min, which is 1 times higher than the removal rate of 33.30% by B-F alone. The removal rate of furacilin by R-B-F prepared from the grinding agent loaded on the R-B modified by calcination under the H2O2 Fenton system is 99.22% at 240 min. The results of SEM show that the surface of R-B modified by calcination is smoother and more conducive to the loading of the grinding agent, which improves the loading capacity per unit area. After the addition of H2O2, there are more active sites on the surface of R-B-F to participate in the reaction, and more ·OH is generated by the catalytic activation of H2O2. R-B-F and oxidants have a catalytic reaction to improve the removal effect of pollutants in water, and exhibit good catalytic performance.

[0058] Example 6

[0059] The grinding agent was prepared by the method in Example 1; the raw bentonite (B) was dried through a 100-mesh sieve; the calcined modified bentonite (R-B) was prepared according to the method in Example 2; and the modified bentonite loaded with the grinding agent (R-B-F-50%) was prepared according to the method in Example 3.

[0060] The grinding agent in Example 6 was prepared by method (1) in the above method; the R-B (calcined modified bentonite) was prepared by method (2); the B-F (raw bentonite loaded with grinding agent) was prepared according to the steps of method (3), and the modified bentonite was replaced by raw bentonite during the preparation process, and the ratio of bentonite to grinding agent was 2:1; and the R-B-F (modified bentonite loaded with grinding agent) was prepared according to the steps of method (3), and the ratio of modified bentonite to grinding agent was 2:1.

[0061] XRD is an effective means to characterize the phase of a catalyst, and the XRD spectrum of the catalyst is as follows Figure 1It can be seen that the diffraction peak of modified bentonite is more, which indicates that its composition is complex. Compared with the standard card (PDF#77-1060), it is found that the characteristic diffraction peaks of montmorillonite are at 2θ = 19.8° and 61.9°, and the characteristic diffraction peak of silicon dioxide is at 26.6°. After the loading of the modified bentonite with the abrasive by the chemical precipitation method is completed, the XRD determination of the modified bentonite loaded abrasive is carried out. The characteristic diffraction peaks of the abrasive appear near 2θ = 42.9° and 44.6°, which correspond to the crystal faces (100) and (101), respectively, and are consistent with the positions of the standard card of iron (50-1275). In addition, the characteristic diffraction peaks of the abrasive appear near 2θ = 30.1°, 35.4°, 56.8° and 62.7°, which correspond to the crystal faces (220), (311), (511) and (440), respectively, and are consistent with the positions of the standard card of Fe3O4(03-0863). The characteristic diffraction peaks of iron at 2θ = 42.9° and 44.6° and the characteristic diffraction peaks of Fe3O4 at 2θ = 30.1°, 35.4°, 56.8° and 62.7° are all present in the XRD spectrum of the composite material, indicating that the loading of the abrasive onto the modified bentonite is successfully completed. It is proved that the magnetism exhibited by the composite material is exhibited by the loaded abrasive, which is also the reason why the composite material can complete the magnetic separation and recycling.

[0062] The stability and reusability of R-B-F were studied at pH = 3, 2 g / L of R-B-F with a loading rate of 50%, and a dosage ratio of H2O2 to solution of 1.0 mL / L. It was found that the removal rate of furilon decreased from 99.29% to 92.75% after 5 cycles, a decrease of 6.54%. The COD removal rate decreased from 69.20% to 65.07% after 5 cycles, a decrease of 4.13%. It can be seen that the removal rate and COD removal rate of R-B-F to furilon are stable under the optimal reaction conditions, and still maintain good removal rate after 5 times of reuse. The catalytic performance of R-B-F does not decrease significantly, and it has good stability and reusability. Figure 5 It can be seen that the diffraction peak of modified bentonite is more, which indicates that its composition is complex. Compared with the standard card (PDF#77-1060), it is found that the characteristic diffraction peaks of montmorillonite are at 2θ = 19.8° and 61.9°, and the characteristic diffraction peak of silicon dioxide is at 26.6°. After the loading of the modified bentonite with the abrasive by the chemical precipitation method is completed, the XRD determination of the modified bentonite loaded abrasive is carried out. The characteristic diffraction peaks of the abrasive appear near 2θ = 42.9° and 44.6°, which correspond to the crystal faces (100) and (101), respectively, and are consistent with the positions of the standard card of iron (50-1275). In addition, the characteristic diffraction peaks of the abrasive appear near 2θ = 30.1°, 35.4°, 56.8° and 62.7°, which correspond to the crystal faces (220), (311), (511) and (440), respectively, and are consistent with the positions of the standard card of Fe3O4(03-0863). The characteristic diffraction peaks of iron at 2θ = 42.9° and 44.6° and the characteristic diffraction peaks of Fe3O4 at 2θ = 30.1°, 35.4°, 56.8° and 62.7° are all present in the XRD spectrum of the composite material, indicating that the loading of the abrasive onto the modified bentonite is successfully completed. It is proved that the magnetism exhibited by the composite material is exhibited by the loaded abrasive, which is also the reason why the composite material can complete the magnetic separation and recycling.

[0063] Example 7

[0064] The weighed modified bentonite was placed in a round flask, 200 mL of anhydrous ethanol-water medium with a volume ratio of 60:40 was added, and it was uniformly dispersed for 10 min. Then, the weighed abrasive agent was added to the flask, and the mass ratio of the two was 2:1, and the total amount was 10 g. The obtained mixed solution was placed in a 20°C water bath and stirred for 4 h. After standing and aging for 24 h, the filtrate was filtered and washed until the pH was neutral. The filtrate was placed in an oven and dried at 100°C for 4 h. It was ground into powder and passed through a 100 mesh sieve to prepare a modified bentonite loaded abrasive composite material, which was named R-B-F-50%.

[0065] The abrasive agent was prepared by the method in Example 1; the raw bentonite (B) was dried and passed through a 100 mesh sieve; the calcined modified bentonite (R-B) was prepared by the method in Example 2; the modified bentonite loaded abrasive composite material (R-B-F-50%) was prepared by the method in Example 3. When preparing the modified diatomite loaded abrasive agent, a certain amount of diatomite was first weighed, and then added to a dilute nitric acid solution with a pH value of 1 at a solid-liquid volume ratio of 1:10. After soaking for 30 min, it was stirred at room temperature for 2 h, and then filtered and washed with deionized water until neutral. The sample was dried at 100°C until the weight was constant. After the sample cooled to room temperature, it was placed in a muffle furnace and calcined at 450°C for 2 h. After cooling, it was taken out and stored for use. A certain amount of modified diatomite was placed in a round flask, and a certain amount of deionized water was added. After uniform dispersion for 10 min, a certain amount of abrasive agent prepared by method (1) was added to the flask, and the ratio of modified diatomite to abrasive agent was 2:1. The mixed solution was placed in a 60°C water bath and stirred for 4 h. After standing and aging for 24 h, it was centrifuged and repeatedly rinsed with deionized water and ethanol until the filtrate was neutral. The filtrate was placed in an oven and dried at 100°C for 4 h. Finally, it was calcined in a 450°C high-temperature muffle furnace for 2 h to prepare a diatomite loaded abrasive composite material.

[0066] The test process was as follows: under the condition of constant temperature (25±2) °C, 200 mL of furacilin solution with a concentration of 100 mg / L was added to three beakers and labeled. 2.0 g / L of the material was added to the three beakers, 1 mL / L of H2O2 was added, the pH of the solution was adjusted to 3, and then the beakers were placed in a constant temperature oscillator. At 3 min, 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min, 10 mL of a syringe was used for timed sampling, and the water samples were filtered with a 0.45 μm needle filter. The experimental results are shown in Table 1. Figure 6

[0067] From the above experimental results, it can be seen that the modified bentonite loaded abrasive composite material has good catalytic activity and can effectively remove furanocillin from water. Figure 6 ​It can be seen that after 60 minutes of reaction, the abrasive alone can achieve 100% removal of pollutants in the Fenton system. The removal rate of furazolidone by diatomaceous earth-loaded abrasive reached 37%, while that by bentonite-loaded abrasive reached 89%. The effect of bentonite loading is much greater than that of diatomaceous earth.

[0068] Example 8

[0069] The grinding agent was prepared according to the method in Example 1: 0.5 g of hexachloroethane, 2.025 g of iron powder, and 4.725 g of iron(III) oxide were added to an 80 mL stainless steel ball mill jar at room temperature (25±2)℃, ensuring a material ratio (iron powder plus iron(III) oxide and hexachloroethane) of 13.5:1, a grinding ball weight of 145 g, a ball-to-material ratio of 20:1, a ball mill speed of 600 rpm, and a total ball milling time of 2 h. After mechanical grinding was completed, the remaining material was cooled to room temperature, and the magnetic material in the remaining material was separated into solid and liquid components using a magnet. The resulting solid was the grinding agent, which was stored in a desiccator for later use.

[0070] The preparation process of Fe / Fe3O4 is the same as in Example 1, except that 0.5g of hexachloroethane is not added during the preparation process to reduce the mass of the grinding balls and ensure that the ball-to-material ratio is 20:1.

[0071] Under constant temperature (25±2)℃, 200 mL of 100 mg / L furacilin solution was added to three beakers and labeled. 2.0 g / L of a grinding agent was added to beaker #2, and 2.0 g / L of Fe and Fe3O4 (mixed and ground in a 3:7 ratio) was added to beaker #3 to adjust the pH of the solution to 3. The beakers were then placed in a constant temperature shaker, and samples were taken at timed intervals of 3 min, 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min using a 10 mL syringe. The water samples were then filtered through a 0.45 μm needle filter.

[0072] Depend on Figure 7 It was found that the concentration of contaminants in the furacilin solution remained almost unchanged within 30 minutes of being left alone, indicating that the furacilin solution is stable under room temperature and light-protected conditions. When treated with an abrasive and ground Fe / Fe3O4, both materials showed some adsorption capacity for furacilin. The abrasive achieved a 32.64% removal rate of furacilin after 30 minutes, while Fe / Fe3O4 only removed 16.29% after 30 minutes, indicating that both materials had limited adsorption capacity for furacilin.

[0073] Example 9

[0074] The grinding agent in Example 9 was prepared using the method of Example 1: 0.5 g of hexachloroethane, 2.025 g of iron powder, and 4.725 g of magnetite were added to an 80 mL stainless steel ball mill jar at room temperature (25±2)℃, ensuring a material ratio (iron powder plus magnetite and hexachloroethane) of 13.5:1, a grinding ball weight of 145 g, a ball-to-material ratio of 20:1, a ball mill speed of 600 rpm, and a total ball milling time of 2 hours. After mechanical grinding was completed, the remaining material was cooled to room temperature, and the magnetic material in the remaining material was separated into solid and liquid components using a magnet. The resulting solid was the grinding agent, which was stored in a desiccator for later use.

[0075] The preparation process of Fe / Fe3O4 is the same as in Example 1, except that 0.5g of hexachloroethane is not added during the preparation process to reduce the mass of the grinding balls and ensure that the ball-to-material ratio is 20:1.

[0076] Under constant temperature (25±2)℃, 200 mL of 100 mg / L furacilin solution was added to four beakers, which were then labeled. 2.0 mL / L of 30% H2O2 was added to beaker #2; 2.0 g / L of a grinding agent and 1.0 mL / L of H2O2 were added to beaker #4; and 2.0 g / L of a uniformly ground mixture of Fe and Fe3O4 (3:7 ratio) and 1 mL / L of H2O2 were added to beaker #3. The pH of the solution was adjusted to 3. The beakers were then placed in a constant temperature shaker, and samples were taken at timed intervals of 3 min, 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min using a 10 mL syringe. The water samples were filtered through a 0.45 μm needle filter. The experimental results are shown in the figure below.

[0077] Depend on Figure 8 It can be seen that adding H2O2 alone has little effect on the removal of furacilin, indicating the absence of a catalyst in the solution. This phenomenon may be due to the oxidation of furacilin solution by the ·OH released from the decomposition of a small amount of H2O2. After adding H2O2, both the grinding agent and the mixed grinding Fe / Fe3O4 form a Fenton system, and the addition of H2O2 in the beaker has a very significant impact on the removal of furacilin by both materials. The effect of H2O2 on the grinding agent is the most significant, with the removal rate of furacilin reaching 97.08% after 15 minutes of reaction. The removal rate of furacilin by Fe / Fe3O4 also increased from 16.29% for adsorption alone to 81.02% after 30 minutes. This indicates that the grinding agent not only has adsorption properties, but also exhibits excellent catalytic performance after the addition of the oxidant, which catalyzes the activation of H2O2 to produce a large amount of ·OH, which reacts chemically with furacilin in the water.

[0078] Example 10

[0079] The grinding agent in Example 10 was prepared by the method of Example 1: 0.5 g of hexachloroethane, 2.025 g of iron powder, and 4.725 g of ferric tetroxide were added to a 80 mL stainless steel ball mill jar at room temperature (25±2) °C, ensuring a material ratio (iron powder plus ferric tetroxide to hexachloroethane) of 13.5:1, a ball weight of 145 g, a ball-to-material ratio of 20:1, a ball mill speed of 600 rpm, and a total ball milling time of 2 h. After the mechanical grinding was completed, the remaining material was cooled to room temperature, and the magnetic material in the remaining material was separated by solid-liquid separation using a magnet. The obtained solid was the grinding agent, which was stored in a desiccator for future use. R-B (roasted modified bentonite) was prepared by the method of Example 2: a certain amount of dry raw bentonite was sieved through a 100 mesh sieve, placed in a porcelain crucible, roasted in a muffle furnace at 450 °C for 2 h, activated at 105-110 °C for 1 h, and then cooled to room temperature to obtain a 450 °C roasted modified modified bentonite, which was packaged for future use. R-B-F (modified bentonite loaded grinding agent) was prepared according to the steps of Example (3): the modified bentonite was placed in a round flask, 200 mL of anhydrous ethanol-water medium with a volume ratio of 60:40 was added, and it was uniformly dispersed for 10 min. Then the grinding agent was added to the flask, and the mass ratio of the two was 2:1, and the total amount was 10 g. The obtained mixed solution was placed in a 20 °C water bath and stirred for 4 h. After standing for 24 h, the filtrate was washed until the pH was neutral. The filtrate was placed in an oven and dried at 100 °C for 4 h. The powder was ground and sieved through a 100 mesh sieve to obtain the modified bentonite loaded grinding agent composite material. According to the different loading rates, it was named R-B-F-loading rate, for example, the modified bentonite loaded grinding agent composite material with a loading rate of 50% was named R-B-F-50%.

[0080] Under constant temperature (25±2) °C conditions, 2.0 g / L of R-B-F composite material with different loading rates was added to 200 mL of initial concentration 100 mg / L furacillin simulated wastewater, 1 mL / L of H2O2 solution was added to all beakers, the pH of the solution was adjusted to 3 using 0.1 mol / L dilute sulfuric acid solution, and then the beakers were placed in a constant temperature oscillator. At 5 min, 10 min, 20 min, 30 min, 60 min, 120 min, 180 min and 240 min, 10 mL of sample was taken with a syringe and filtered with a 0.45 μm needle filter.

[0081] From Figure 9As can be seen from the figure, with the increase of the grinding agent load rate, the removal rate of furagilin by R-B-F also shows an upward trend in the same time. When the grinding agent load rate reaches 50%, the removal rate of furagilin by the Fenton system constructed by R-B-F and H2O2 is as high as 99.22% at 240 min. When the load rate is 60%, the furagilin in the wastewater can be completely removed at 240 min. SEM proves that the bentonite is a layered structure, the combination of the grinding agent and the bentonite is that the grinding agent is attached to the surface of the bentonite, and with the increase of the load of the grinding agent, the content of iron element in the composite material which catalyzes the activation reaction with the oxidant also increases, and the catalytic efficiency is improved, so that the removal effect of the pollutants is better.

[0082] Example 11

[0083] The preparation process of R-B-F (modified bentonite loaded with grinding agent) in Example 11 is prepared according to the steps of Example (3). The weighed modified bentonite is placed in a round flask, 200 mL of anhydrous ethanol-water medium with a volume ratio of 60:40 is added, and it is uniformly dispersed for 10 min. Then the weighed grinding agent is added to the flask, and the mass ratio of the two is 2:1, and the total amount is 10 g. The obtained mixed solution is placed in a water bath at 20°C and stirred for 4 h. After standing and aging for 24 h, the filtrate is filtered and washed until the pH is neutral. The filtrate is placed in an oven and dried at 100°C for 4 h. It is ground into powder and passed through a 100 mesh sieve to prepare a composite material of modified bentonite loaded with grinding agent, which is named R-B-F-50%.

[0084] The pH of natural bentonite is from weakly acidic to neutral, and the pH range of the material after adding bentonite is larger than that of the grinding agent alone, showing better applicability. Therefore, under the condition of constant temperature (25±2) °C, 2.0 g / L of R-B-F with a load rate of 50% and 1 mL / L of 30% H2O2 solution are added to 200 mL of simulated wastewater with an initial concentration of 100 mg / L of furagilin. The pH of the solution is adjusted to 2-9 by using 0.1 mol / L dilute sulfuric acid solution. Then the beaker is placed in a constant temperature oscillator, and 10 mL of syringe is used for timed sampling at 5 min, 10 min, 20 min, 30 min, 60 min, 120 min, 180 min and 240 min. The water samples are filtered by using a 0.45 μm needle filter. The experimental results are shown in the following figure.

[0085] The removal rate of furacilin decreased with increasing solution pH. As the initial pH increased from 2 to 9, the removal rate dropped from 100% to 30.67% after 240 min of reaction. When the pH was greater than 5, the removal rate of furacilin could not reach 50%. At 240 min, the removal rates of furacilin at pH=2 and pH=3 were both above 99%. This is mainly because under acidic conditions, in addition to the physical adsorption of pollutants by bentonite itself, Fe in RBF can be converted to Fe more rapidly. 2+ It catalyzes the production of more ·OH, accelerating the removal of pollutants.

[0086] Example 12

[0087] The preparation process of RBF (modified bentonite-loaded abrasive) in Example 12 is carried out according to the steps of Example (3). The weighed modified bentonite is placed in a round-mouth flask, and 200 mL of anhydrous ethanol-water medium with a volume ratio of 60:40 is added. The mixture is evenly dispersed for 10 min. Then, the weighed abrasive is added to the flask. The mass ratio of the two is 2:1, and the total amount is 10 g. The resulting mixed solution is placed in a 20°C water bath and stirred for 4 h. After standing and aging for 24 h, it is filtered and washed until the pH of the filtrate is neutral. The filtrate is placed in an oven and dried at 100°C for 4 h. It is then ground into powder and passed through a 100-mesh sieve to obtain the composite material of modified bentonite-loaded abrasive, which is named RBF-50%.

[0088] Five RBF dosages were set to investigate the effect on the removal rate of 200 mL of simulated furazolidone wastewater with an initial concentration of 100 mg / L under the conditions of constant temperature (25±2)℃, 1 mL / L 30% H2O2 solution, and pH=3.

[0089] Depend on Figure 11 It can be seen that with the increase of RBF dosage, the removal rate of furacilin within the same time period shows an upward trend. The removal rate increases rapidly before 60 minutes, and then the increase slows down after 60 minutes, the reaction rate decreases, and the adsorption and oxidation in the system gradually tend to reach equilibrium. In the initial stage of the reaction, the effective active sites on the RBF surface are abundant, and ·OH can be quickly generated during adsorption to oxidize and remove pollutants. As the reaction proceeds, the number of active sites decreases, and the removal rate tends to slow down. When the dosage reaches 4 g / L, the removal rate of furacilin is 97.76%, which is less than that of 2 g / L (99.29%) and 3 g / L (100%). This is partly because the Fe produced by the catalytic reaction of excessive RBF increases with the addition of RBF. 2+ The SEM images showed an increase in the amount of abrasive adhering to the bentonite surface, where the bentonite remained clearly visible, and the Fe in the solution increased. 2+contacting with bentonite, into the crystal layer structure of bentonite, reduced the Fe 2+ concentration leads to a decrease in the catalytic reaction with H2O2; on the other hand, an excess of R-B-F can lead to polymerization between the particles, which reduces the specific surface area of the material and increases the diffusion path of the pollutants.

[0090] Example 13

[0091] The preparation process of R-B-F (modified bentonite loaded abrasive) in Example 13 was prepared according to the steps of Example (3). The weighed modified bentonite was placed in a round flask, 200 mL of anhydrous ethanol-water medium with a volume ratio of 60:40 was added, and it was uniformly dispersed for 10 min. Then the weighed abrasive was added to the flask, and the mass ratio of the two was 2:1, and the total amount was 10 g. The resulting mixed solution was placed in a water bath at 20°C and stirred for 4 h. After standing and aging for 24 h, the filtrate was filtered and washed until the pH was neutral. The filtrate was placed in an oven and dried at 100°C for 4 h. It was ground into powder and passed through a 100 mesh sieve to prepare a modified bentonite loaded abrasive composite material, which was named R-B-F-50%.

[0092] H2O2 is the "engine" of the Fenton system for removing pollutants and mineralizing the COD of the solution. Five H2O2 dosing ratios were set to study the effect on the removal rate of furanocin simulated wastewater under the conditions of constant temperature (25±2) °C, pH=3, and 2 g / L of R-B-F. From Figure 12 It can be seen that when the dosing ratio increases from 0 ml / L to 1.5 ml / L, with the increase of H2O2 dosing ratio, the removal rate of furanocin shows an upward trend in the same reaction time, and the removal rate of furanocin increases from 34.16% to 100%. The removal rates of furanocin after 180 min of reaction at 1 ml / L and 1.5 ml / L are basically the same, which shows that within a certain limit and time, increasing the dosing ratio of H2O2 can improve the removal efficiency of pollutants, and beyond the limit, the improvement of the removal rate is limited. When the dosing ratio of H2O2 continues to increase, the removal rate of furanocin begins to decrease. This trend may be due to the fact that when the dosing ratio of H2O2 is insufficient, it is not enough to completely oxidize and remove the pollutants, and the removal rate of the pollutants is low; when the dosing of H2O2 is excessive, the amount of material in the solution is not enough to completely catalyze, so that H2O2 cannot fully participate in the removal reaction.

Claims

1. A catalyst based on ball-milling degradation residues, characterized in that The catalyst is prepared as follows: (1) Dry raw bentonite is passed through a 100-mesh sieve, calcined in a muffle furnace at 400-500°C for 2 h, and activated at 105-110°C for 1 h to obtain modified bentonite; (2) The modified bentonite and ball-milling degradation residue obtained in step (1) are uniformly dispersed in an ethanol aqueous solution with a volume fraction of 55%-65%, stirred in a water bath at 17-23°C for 3.5-4.5 h, and allowed to stand for 22-26 h. The obtained reaction solution is subjected to post-treatment to obtain the catalyst based on the ball-milling degradation residue; the mass ratio of the modified bentonite to the ball-milling degradation residue is 10:1-6; The ball-milling degradation residue is a magnetic material obtained by degradation of hexachloroethane under ball-milling conditions using iron powder and ferroferric oxide; The ball-milling degradation residue is obtained as follows: Hexachloroethane, iron powder and ferroferric oxide are mixed and subjected to ball-milling degradation at room temperature for 1.8-2.2 h. After cooling to room temperature, the obtained mixture is subjected to solid-liquid separation using a magnet. The solid adhered to the magnet is the ball-milling degradation residue; the mass ratio of hexachloroethane, iron powder and ferroferric oxide is 1:4-4.1:9.3-9.

6.

2. The catalyst based on ball-milling degradation residue according to claim 1, characterized in that: The ball-milling conditions are as follows: the ball-to-material ratio is 20:1, the rotation speed of the ball mill is 600 rpm, the rotation is alternately operated for 30 min, and the total ball-milling time is 2 h.

3. The catalyst based on ball-milling degradation residue according to claim 1, characterized in that: In step (2), the volume of the ethanol aqueous solution is 10-30 mL / g based on the total mass of the modified bentonite and the ball-milling degradation residue.

4. The catalyst based on ball-milling degradation residue according to claim 1, characterized in that: In step (2), the post-treatment is as follows: the reaction solution is filtered, washed repeatedly with deionized water until the filtrate is neutral, the obtained filter cake is dried, ground into powder, and passed through a 100-mesh sieve to obtain the catalyst based on the ball-milling degradation residue.

5. Use of the catalyst based on the ball-milling degradation residue in the degradation of organic contaminant wastewater.

6. Use according to claim 5, wherein: The organic contaminant in the organic contaminant wastewater is furagilin.

7. The use according to claim 5, wherein The use is as follows: the catalyst based on the ball-milling degradation residue is added to the organic contaminant wastewater to construct a degradation system, the pH is adjusted to 3, and degradation is performed.

8. Use according to claim 7, wherein: In the degradation system, the concentration of the catalyst based on the ball-milling degradation residue is 1.8-2.2 g / L; and the concentration of the organic contaminant in the organic contaminant wastewater is 80-120 mg / L.

9. The use according to claim 7, wherein: The degradation system further comprises hydrogen peroxide; in the degradation system, the mass fraction of hydrogen peroxide is 0.25-0.35%.

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