A nano Co2O3 / Fe3O4 composite PMS activation catalyst, a preparation method and application thereof

Abstract

The application discloses a kind of nano Co2O3 / Fe3O4 Composite PMS activation catalyst and its preparation method and application, belong to nanometer catalytic material technical field. Including the following weight parts raw materials: 18-36 parts modified chitosan, 100-200 parts citric acid solution, 3-7 parts cobalt chloride hexahydrate, 4-8 parts iron chloride hexahydrate. The catalyst prepared by loading Fe3O4 And Co2O3 Nanoparticles in biological carbon material, the activation of bimetallic catalysis PMS is better;And the magnetism of Fe is conducive to the recovery of catalyst, reduces cost;By modifying chitosan, the activation efficiency of catalyst to PMS is enhanced;Therefore, the catalyst prepared by the application is chitosan as base material, load Fe and Co and doped N and S, the prepared catalyst has synergistic effect, the activation efficiency of PMS is extremely high, and can be recycled by magnetic force, low in cost, has significant application value in water treatment industry.

Description

Technical Field

[0001] This invention belongs to the field of nanocatalytic materials technology, specifically relating to a nano-Co2O3 / Fe3O4 composite PMS activated catalyst, its preparation method, and its application. Background Technology

[0002] In water pollution control, persulfate catalytic treatment of wastewater has attracted much attention and research due to its advantages such as high efficiency, speed, energy saving, and environmental friendliness. This technology generates highly reactive free radicals such as sulfate radicals (SO4· ... - Persulfate catalytic oxidation (PCO) or oxygen free radicals (·OH) possess strong oxidizing power, effectively decomposing organic matter in water, including dissolved organic matter, color substances, and recalcitrant organic matter. Its rapid reaction speed allows wastewater to be treated quickly, improving treatment efficiency, and is particularly suitable for situations requiring rapid treatment. Furthermore, the generated active free radicals can oxidize organic matter in water without the need for additional oxygen or oxidants, thus reducing treatment costs. PCO catalytic wastewater treatment technology is applicable to various types of organic wastewater, including industrial wastewater, rural sewage, and domestic sewage, demonstrating broad applicability. Since the operation is carried out at room temperature, eliminating the need for high-temperature conditions, energy consumption and operating costs are reduced. The reaction products of this technology are typically non-toxic and harmless, causing no secondary pollution to the environment. In the future, through continuous research and improvement of water pollution control technologies, PCO catalytic wastewater treatment technology is expected to be further optimized and enhanced.

[0003] Patent CN114054028A discloses a method for preparing a Cu2O / CoFe2O4 magnetic composite catalyst, comprising the following steps: ultrasonically dispersing cobalt ferrite in distilled water, adding a certain amount of 0.5 mol / L copper sulfate solution after ultrasonication, and stirring at room temperature for 60 min; adding sodium hydroxide solution dropwise while continuously stirring, followed by adding ascorbic acid solution dropwise; stirring and reacting at 20°C for 2 h to obtain a cuprous oxide / cobalt ferrite dispersion; filtering the dispersion and washing it repeatedly with anhydrous ethanol and distilled water 3-5 times to remove impurities, and drying at 80°C to obtain the Cu2O / CoFe2O4 magnetic composite catalyst. The process is simple, and the prepared Cu2O / CoFe2O4 magnetic composite catalyst has high purity, strong stability, and is easy to recover and recycle. However, the catalytic efficiency of this catalyst is low and cannot meet the requirements for large-scale industrial applications. Therefore, it is urgent to solve the above problems to meet the higher requirements of the field of nanocatalytic materials technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a nano-Co2O3 / Fe3O4 composite PMS activated catalyst, its preparation method, and its application.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing a nano-Co2O3 / Fe3O4 composite PMS activated catalyst includes the following steps:

[0007] A1. Dissolve the modified chitosan in citric acid solution and stir until homogeneous. Add cobalt chloride hexahydrate and ferric chloride hexahydrate and continue stirring to obtain a mixed solution.

[0008] A2. Place the mixed solution obtained in step A1 into a constant temperature water bath, stir until the liquid evaporates to dryness, then scrape off the sample and dry it to obtain a mixed solid.

[0009] A3. Add the mixed solid obtained in step A2 into a ceramic boat, place the whole in a tube furnace, and calcine it with inert gas. After calcine is completed, let the tube furnace cool naturally to room temperature, immerse the product in hydrochloric acid solution for stirring and acid washing, then wash it multiple times with ultrapure water until the filtrate is neutral, then wash it 3-4 times with anhydrous ethanol, and finally dry it to obtain the nano-Co2O3 / Fe3O4 composite PMS activated catalyst.

[0010] Furthermore, the raw materials are as follows by weight: 18-36 parts modified chitosan, 100-200 parts citric acid solution, 3-7 parts cobalt chloride hexahydrate, and 4-8 parts ferric chloride hexahydrate.

[0011] Furthermore, the drying conditions in step A2 are drying at 80-100°C in a vacuum oven for 6-12 hours.

[0012] Furthermore, the inert gas in step A3 is either nitrogen or argon.

[0013] Furthermore, in step A3, the calcination conditions are as follows: heating to 600-800℃ at a heating rate of 2℃ / min, and holding at that temperature for 2-5 hours.

[0014] Furthermore, the drying conditions in step A3 are drying at 80-100℃ in a vacuum oven for 6-12 hours.

[0015] By loading Fe3O4 and Co2O3 nanoparticles onto biocarbon materials (chitosan), bimetallic materials can modulate the electronic structure, resulting in better activation efficiency compared to single-metal materials. This effectively prevents catalyst aggregation while increasing the specific surface area and surface active sites, significantly improving catalytic efficiency. Furthermore, the introduction of Fe enhances the graphitization of the biocarbon material and forms a core-shell structure, strengthening electron transfer and enhancing the activation ability of PMS. Moreover, the magnetic properties of Fe3O4 and Co2O3 facilitate magnetic separation and recovery of the catalyst in solution, reducing operating costs.

[0016] Furthermore, the modified chitosan is prepared through the following steps:

[0017] S1. In a three-necked flask equipped with a stirrer, 2,5-thiophene dicarboxylic acid, 4-aminopyridine, dicyclohexylcarbodiimide (DCC, dehydrating agent) and toluene were stirred and mixed evenly. The mixture was then placed in a water bath at 55°C and heated for 6 hours. After the reaction was completed, the mixture was filtered, the solvent was removed by vacuum distillation, and then purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 2:3). The eluent was removed by rotary evaporation to obtain the modifier. The ratio of 2,5-thiophene dicarboxylic acid, 4-aminopyridine, dicyclohexylcarbodiimide, and toluene was 18.4 g: 9.4 g: 20.6 g: 100 mL.

[0018] Under the action of a dehydrating agent, 2,5-thiophene dicarboxylic acid and 4-aminopyridine undergo an amidation reaction. By controlling the molar ratio of the two to be close to 1:1 and with a slight excess of 2,5-thiophene dicarboxylic acid, only one carboxyl group on the 2,5-thiophene dicarboxylic acid participates in the reaction, resulting in a modifier. The specific reaction process is shown below:

[0019]

[0020] S2. Chitosan was added to a mixed solution of acetic acid and toluene (acetic acid mass fraction was 24%) and stirred until completely dissolved. Then, the modifier and dicyclohexylcarbodiimide were added. The reaction temperature was controlled at 60℃ and the reaction was maintained at this temperature for 12 hours. After the reaction was completed, the mixture was distilled under reduced pressure, washed successively with ethanol and water, and dried in an oven to obtain modified chitosan. The ratio of the mixed solution of acetic acid and toluene, chitosan, modifier, and dicyclohexylcarbodiimide was 100mL:1g:2.4g:15mL.

[0021] Under the action of dicyclohexylcarbodiimide, the carboxyl group on the modifier undergoes an amidation reaction with the amino group on chitosan to obtain modified chitosan;

[0022] Chitosan is a biocarbon material, a carbon-rich substance with wide availability, eco-friendliness, low cost, and renewability. Calcination can form porous materials, and the structural defects produced during calcination help activate PMS. By modifying chitosan and grafting pyridine and thiophene structures onto it, the lone pair of electrons in pyridine N can interact with sp... 2 The free-flowing π electrons abundant in C undergo conjugation, thereby triggering higher catalytic activity. Pyridine N can also form Fe-NX active sites with Fe, further enhancing catalytic activity. In addition, the introduced thiophene S can not only enhance the electron density and asymmetric spin of biocarbon materials and promote the adsorption of PMS, but also serve as an active site for PMS, further enhancing catalytic activity.

[0023] The beneficial effects of this invention are:

[0024] 1. The catalyst prepared by this invention, by loading Fe3O4 nanoparticles and Co2O3 nanoparticles into biochar material, enhances the bimetallic catalytic activation of PMS; and the magnetic properties of Fe3O4 and Co2O3 facilitate the magnetic separation and recovery of the catalyst in solution, reducing the cost of use.

[0025] 2. By modifying chitosan and introducing pyridine N and thiophene S, the active sites of the catalyst were significantly improved, and the activation efficiency of the catalyst for PMS was enhanced.

[0026] Therefore, the catalyst prepared by this invention uses chitosan as a base material, which is inexpensive. By loading Fe and Co and doping with N and S, the catalyst has a synergistic effect, has extremely high activation efficiency for PMS, and can be recovered by magnetic force, further reducing costs. It has significant application value in the water treatment industry. Attached Figure Description

[0027] The invention will now be further described with reference to the accompanying drawings.

[0028] Figure 1 This is a SEM image of the nano-Co2O3 / Fe3O4 composite PMS activated catalyst prepared in Example 1 of this invention.

[0029] Figure 2 This is a SEM image of the nano-Co2O3 / Fe3O4 composite PMS activated catalyst prepared in Example 2 of the present invention.

[0030] Figure 3 This is a SEM image of the nano-Co2O3 / Fe3O4 composite PMS activated catalyst prepared in Example 3 of the present invention.

[0031] Figure 4 The image shows the VSM hysteresis loop diagram of the nano-Co2O3 / Fe3O4 composite PMS activated catalyst prepared in Example 1 of this invention.

[0032] Figure 5 This is a photograph of the nano-Co2O3 / Fe3O4 composite PMS activated catalyst obtained in Example 1 of this invention, showing its magnetic adsorption properties.

[0033] Figure 6 The degradation curves of R6G by the Co2O3 / Fe3O4 composite PMS activated catalyst prepared in Examples 1-5 of this invention are shown.

[0034] Figure 7 The degradation efficiency curve of R6G by the Co2O3 / Fe3O4 composite PMS activated catalyst prepared in Example 1 of this invention during recycling is shown. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] A1. Dissolve 36g of modified chitosan in 200g of citric acid solution (12% by mass) and stir for 2 hours to mix evenly. Add 7g of cobalt chloride hexahydrate and 8g of ferric chloride hexahydrate, and continue stirring and mixing for 2 hours to obtain a mixed solution.

[0038] A2. Place the mixed solution obtained in step A1 in a constant temperature water bath at 80°C and stir until the liquid evaporates to dryness. Then scrape out the sample and dry it in a vacuum oven at 100°C for 12 hours to obtain a mixed solid.

[0039] A3. Add the mixed solid obtained in step A2 into a ceramic boat, place the whole in a tube furnace, and purge with nitrogen. Heat to 800°C at a heating rate of 2°C / min and calcine for 5 hours. After calcineation is complete, allow the tube furnace to cool naturally to room temperature. Immerse the product in hydrochloric acid solution (12% by mass) and stir to wash it. Then wash it multiple times with ultrapure water until the filtrate is neutral. Wash it four times with anhydrous ethanol. Finally, dry it in a vacuum oven at 100°C for 12 hours to obtain the nano-Co2O3 / Fe3O4 composite PMS activated catalyst.

[0040] Modified chitosan is prepared through the following steps:

[0041] S1. In a three-necked flask equipped with a stirrer, 18.4 g of 2,5-thiophene dicarboxylic acid, 9.4 g of 4-aminopyridine, 20.6 g of dicyclohexylcarbodiimide and 100 mL of toluene were stirred and mixed evenly. The mixture was then placed in a water bath at 55 °C and heated for 6 h. After the reaction was completed, the mixture was filtered, the solvent was removed by vacuum distillation, and then purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 2:3). The eluent was removed by rotary evaporation to obtain the modifier.

[0042] S2. Add 1g of chitosan to a 100mL mixed solution of acetic acid and toluene (acetic acid mass fraction is 24%), stir until completely dissolved, then add 2.4g of modifier and 15mL of dicyclohexylcarbodiimide, control the reaction temperature at 60℃, keep the reaction at this temperature for 12h, after the reaction is complete, distill under reduced pressure, wash with ethanol and water successively, and dry in an oven to obtain modified chitosan.

[0043] Embodiment 1 will be described in conjunction with the accompanying drawings, such as Figure 1 As shown in the figure, it can be clearly seen that the sample is granular and has good dispersibility; Figure 4 As shown in the figure, the sample's magnetism is as high as 29.8 emu / g; the actual photograph of the magnet adsorbing the sample is shown below. Figure 5 As shown, it is evident that the catalyst inside the centrifuge tube is firmly adsorbed by the magnet at the top of the tube without falling off, indicating its strong magnetic properties, which facilitates recovery. The degradation rate change after 5 cycles is shown in the figure. Figure 7 As shown in the figure, after five cycles of use, although the degradation rate of R6G by the catalyst in 20 minutes decreased, it still reached 93.2%, indicating that the catalyst has good stability, can be recycled and reused, and can reduce the cost of use.

[0044] Example 2

[0045] A1. Dissolve 20g of modified chitosan in 175g of citric acid solution (12% by mass) and stir for 1 hour to mix evenly. Add 6g of cobalt chloride hexahydrate and 7g of ferric chloride hexahydrate, and continue stirring and mixing for 1 hour to obtain a mixed solution.

[0046] A2. Place the mixed solution obtained in step A1 in a constant temperature water bath at 80°C and stir until the liquid evaporates to dryness. Then scrape out the sample and dry it in a vacuum oven at 100°C for 12 hours to obtain a mixed solid.

[0047] A3. Add the mixed solid obtained in step A2 into a ceramic boat, place the whole in a tube furnace, and purge with nitrogen. Heat to 750°C at a heating rate of 2°C / min and calcine for 4 hours. After calcineation is complete, allow the tube furnace to cool naturally to room temperature. Immerse the product in hydrochloric acid solution (12% by mass) and stir to wash it. Then wash it multiple times with ultrapure water until the filtrate is neutral. Wash it four times with anhydrous ethanol. Finally, dry it in a vacuum oven at 100°C for 12 hours to obtain the nano-Co2O3 / Fe3O4 composite PMS activated catalyst.

[0048] Modified chitosan is prepared through the following steps:

[0049] S1. In a three-necked flask equipped with a stirrer, 18.4 g of 2,5-thiophene dicarboxylic acid, 9.4 g of 4-aminopyridine, 20.6 g of dicyclohexylcarbodiimide and 100 mL of toluene were stirred and mixed evenly. The mixture was then placed in a water bath at 55 °C and heated for 6 h. After the reaction was completed, the mixture was filtered, the solvent was removed by vacuum distillation, and then purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 2:3). The eluent was removed by rotary evaporation to obtain the modifier.

[0050] S2. Add 1g of chitosan to a 100mL mixed solution of acetic acid and toluene (acetic acid mass fraction is 24%), stir until completely dissolved, then add 2.4g of modifier and 15mL of dicyclohexylcarbodiimide, control the reaction temperature at 60℃, keep the reaction at this temperature for 12h, after the reaction is complete, distill under reduced pressure, wash with ethanol and water successively, and dry in an oven to obtain modified chitosan.

[0051] like Figure 2 As shown in the figure, it can be clearly seen that the sample is granular and has a good hybridization effect.

[0052] Example 3

[0053] A1. Dissolve 24g of modified chitosan in 150g of citric acid solution (12% by mass) and stir for 1 hour to mix evenly. Add 5g of cobalt chloride hexahydrate and 6g of ferric chloride hexahydrate, and continue stirring and mixing for 2 hours to obtain a mixed solution.

[0054] A2. Place the mixed solution obtained in step A1 in a constant temperature water bath at 80°C and stir until the liquid evaporates to dryness. Then scrape out the sample and dry it in a vacuum oven at 100°C for 12 hours to obtain a mixed solid.

[0055] A3. Add the mixed solid obtained in step A2 into a ceramic boat, place the whole in a tube furnace, and introduce argon gas. Heat the furnace to 700°C at a heating rate of 2°C / min and calcine for 4 hours. After calcineation is complete, allow the tube furnace to cool naturally to room temperature. Soak the product in hydrochloric acid solution (mass fraction 12%) for stirring and acid washing. Then wash it multiple times with ultrapure water until the filtrate is neutral. Wash it 3-4 times with anhydrous ethanol. Finally, dry it in a vacuum oven at 100°C for 12 hours to obtain the nano-Co2O3 / Fe3O4 composite PMS activated catalyst.

[0056] Modified chitosan is prepared through the following steps:

[0057] S1. In a three-necked flask equipped with a stirrer, 18.4 g of 2,5-thiophene dicarboxylic acid, 9.4 g of 4-aminopyridine, 20.6 g of dicyclohexylcarbodiimide and 100 mL of toluene were stirred and mixed evenly. The mixture was then placed in a water bath at 55 °C and heated for 6 h. After the reaction was completed, the mixture was filtered, the solvent was removed by vacuum distillation, and then purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 2:3). The eluent was removed by rotary evaporation to obtain the modifier.

[0058] S2. Add 1g of chitosan to a 100mL mixed solution of acetic acid and toluene (acetic acid mass fraction is 24%), stir until completely dissolved, then add 2.4g of modifier and 15mL of dicyclohexylcarbodiimide, control the reaction temperature at 60℃, keep the reaction at this temperature for 12h, after the reaction is complete, distill under reduced pressure, wash with ethanol and water successively, and dry in an oven to obtain modified chitosan.

[0059] like Figure 3 As shown in the figure, it can be clearly seen that the sample is granular and has a good hybridization effect.

[0060] Example 4

[0061] A1. Dissolve 20g of modified chitosan in 125g of citric acid solution (12% by mass) and stir for 1 hour to mix evenly. Add 4g of cobalt chloride hexahydrate and 5g of ferric chloride hexahydrate, and continue stirring and mixing for 1 hour to obtain a mixed solution.

[0062] A2. Place the mixed solution obtained in step A1 in a constant temperature water bath at 80°C and stir until the liquid evaporates to dryness. Then scrape out the sample and dry it in a vacuum oven at 80°C for 6 hours to obtain a mixed solid.

[0063] A3. Add the mixed solid obtained in step A2 into a ceramic boat, place the whole in a tube furnace, and introduce argon gas. Heat the furnace to 650°C at a heating rate of 2°C / min and calcine for 2 hours. After calcineation is complete, allow the tube furnace to cool naturally to room temperature. Immerse the product in hydrochloric acid solution (mass fraction 12%) for stirring and acid washing. Then wash it multiple times with ultrapure water until the filtrate is neutral. Wash it three times with anhydrous ethanol. Finally, dry it in a vacuum oven at 80°C for 6 hours to obtain the nano-Co2O3 / Fe3O4 composite PMS activated catalyst.

[0064] Modified chitosan is prepared through the following steps:

[0065] S1. In a three-necked flask equipped with a stirrer, 18.4 g of 2,5-thiophene dicarboxylic acid, 9.4 g of 4-aminopyridine, 20.6 g of dicyclohexylcarbodiimide and 100 mL of toluene were stirred and mixed evenly. The mixture was then placed in a water bath at 55 °C and heated for 6 h. After the reaction was completed, the mixture was filtered, the solvent was removed by vacuum distillation, and then purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 2:3). The eluent was removed by rotary evaporation to obtain the modifier.

[0066] S2. Add 1g of chitosan to a 100mL mixed solution of acetic acid and toluene (acetic acid mass fraction is 24%), stir until completely dissolved, then add 2.4g of modifier and 15mL of dicyclohexylcarbodiimide, control the reaction temperature at 60℃, keep the reaction at this temperature for 12h, after the reaction is complete, distill under reduced pressure, wash with ethanol and water successively, and dry in an oven to obtain modified chitosan.

[0067] Example 5

[0068] A1. Dissolve 18g of modified chitosan in 100g of citric acid solution (12% by mass) and stir for 0.5h to mix evenly. Add 3g of cobalt chloride hexahydrate and 4g of ferric chloride hexahydrate, and continue stirring for 0.5h to obtain a mixed solution.

[0069] A2. Place the mixed solution obtained in step A1 in a constant temperature water bath at 80°C and stir until the liquid evaporates to dryness. Then scrape out the sample and dry it in a vacuum oven at 80°C for 6 hours to obtain a mixed solid.

[0070] A3. Add the mixed solid obtained in step A2 into a ceramic boat, place the whole in a tube furnace, and introduce argon gas. Heat the furnace to 600℃ at a heating rate of 2℃ / min and calcine for 2 hours. After calcineation is complete, let the tube furnace cool naturally to room temperature. Soak the product in hydrochloric acid solution (mass fraction 12%) for stirring and acid washing. Then wash it multiple times with ultrapure water until the filtrate is neutral. Wash it three times with anhydrous ethanol. Finally, dry it in a vacuum oven at 80℃ for 6 hours to obtain the nano-Co2O3 / Fe3O4 composite PMS activated catalyst.

[0071] Modified chitosan is prepared through the following steps:

[0072] S1. In a three-necked flask equipped with a stirrer, 18.4 g of 2,5-thiophene dicarboxylic acid, 9.4 g of 4-aminopyridine, 20.6 g of dicyclohexylcarbodiimide and 100 mL of toluene were stirred and mixed evenly. The mixture was then placed in a water bath at 55 °C and heated for 6 h. After the reaction was completed, the mixture was filtered, the solvent was removed by vacuum distillation, and then purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 2:3). The eluent was removed by rotary evaporation to obtain the modifier.

[0073] S2. Add 1g of chitosan to a 100mL mixed solution of acetic acid and toluene (acetic acid mass fraction is 24%), stir until completely dissolved, then add 2.4g of modifier and 15mL of dicyclohexylcarbodiimide, control the reaction temperature at 60℃, keep the reaction at this temperature for 12h, after the reaction is complete, distill under reduced pressure, wash with ethanol and water successively, and dry in an oven to obtain modified chitosan.

[0074] 2 mM persulfate was added to 50 mL of a 50 mg / L Rhodamine 6G (R6G) solution. After stirring, 10 mg of the catalyst prepared in Examples 1-5 was added to the solution. The mixture was stirred to carry out the degradation experiment. 2 mL samples were taken at intervals, and 20 μL of a 1 M sodium sulfate (Na2SO4) solution was added to the samples to terminate the degradation reaction. The R6G concentration in the samples was then measured using a UV spectrophotometer. Degradation rate (%) = (initial R6G concentration - R6G concentration after degradation) / initial R6G concentration × 100%.

[0075] The measured degradation rates are shown in Table 1:

[0076] Table 1

[0077]

[0078]

[0079] Based on the degradation rate test results of R6G in Examples 1-5 in Table 1, Figure 6 Degradation curves and Figure 7 As shown in the degradation efficiency variation graph, the nano-Co2O3 / Fe3O4 composite PMS activation catalysts prepared by the methods in all embodiments of this application exhibit excellent catalytic performance and magnetic properties. Example 1 shows a degradation rate as high as 96.8% and a magnetic property as high as 29.8 emu / g; after 5 cycles, the degradation rate remains as high as 93.2%. Notably, the catalysts prepared in all embodiments can degrade more than 85% of R6G within 1 minute, demonstrating the catalyst's high efficiency and high stability. Therefore, the catalysts prepared in this invention have extremely high PMS activation efficiency and can be magnetically recovered, making them significant for application in the water treatment industry.

[0080] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0081] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a nano Co2O3 / Fe3O4 composite PMS activation catalyst, characterized in that, It comprises the following steps: A1, the modified chitosan is dissolved in the citric acid solution and stirred to mix uniformly, then the cobalt chloride hexahydrate and the ferric chloride hexahydrate are added and continue to be stirred and mixed, to obtain a mixed solution; A2, the mixed solution obtained in step A1 is placed in a constant temperature water bath, and is stirred until the liquid is evaporated, then the sample is scraped out and dried, to obtain a mixed solid; A3, the mixed solid obtained in step A2 is added to a porcelain boat, and the whole is placed in a tube furnace, and an inert gas is introduced, calcination, after the calcination is completed, the tube furnace is naturally cooled to room temperature, the product is immersed in a hydrochloric acid solution and stirred for pickling, then washed to neutral, washed again, and finally dried, to obtain a nano Co2O3 / Fe3O4 composite PMS activated catalyst; The modified chitosan is prepared by the following steps: S1, 2, 5-thiophene dicarboxylic acid, 4-aminopyridine, dicyclohexyl carbodiimide and toluene are stirred and mixed uniformly, then heated at 55℃ for 6h, after the reaction is completed, filtered, distilled under reduced pressure, purified by column chromatography, and rotary evaporated, to obtain a modifier; S2, the chitosan is added to a mixed solution of acetic acid and toluene, stirred until completely dissolved, then the modifier and dicyclohexyl carbodiimide are added, and reacted at 60℃ for 12h, after the reaction is completed, distilled under reduced pressure, washed, and dried, to obtain the modified chitosan; In step A3, the calcination condition is to heat at a heating rate of 2℃ / min to 600-800℃, and keep the temperature for 2-5h.

2. The preparation method of the nano Co2O3 / Fe3O4 composite PMS activation catalyst according to claim 1, characterized in that, In step S1, the amount ratio of 2, 5-thiophene dicarboxylic acid, 4-aminopyridine, dicyclohexyl carbodiimide, and toluene is 18.4g:9.4g:20.6g:100mL.

3. The preparation method of the nano Co2O3 / Fe3O4 composite PMS activation catalyst according to claim 1, characterized in that, In step S2, the amount ratio of the mixed solution of acetic acid and toluene, the chitosan, the modifier, and dicyclohexyl carbodiimide is 100mL:1g:2.4g:15mL.

4. The preparation method of the nano Co2O3 / Fe3O4 composite PMS activation catalyst according to claim 1, characterized in that, The amount of each raw material is as follows: 18-36 parts of modified chitosan, 100-200 parts of citric acid solution, 3-7 parts of cobalt chloride hexahydrate, and 4-8 parts of ferric chloride hexahydrate.

5. The preparation method of the nano Co2O3 / Fe3O4 composite PMS activation catalyst according to claim 1, characterized in that, The inert gas in step A3 is one of nitrogen and argon.

6. A nano Co2O3 / Fe3O4 composite PMS activated catalyst, characterized in that, Prepared according to the method of any one of claims 1-5. 7.The nano Co 2O 3 / Fe 3O 4 composite PMS-activated catalyst according to claim 6, characterized in that, Application in the field of water treatment.

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