A method for removing organic pollutants from a water body using a three-dimensional aerogel composite material

Abstract

The application discloses a method for removing organic pollutants in water bodies by using a three-dimensional aerogel composite material, and comprises the following steps: oscillating and mixing the three-dimensional aerogel composite material with the water bodies containing organic pollutants for adsorption, then adding a certain amount of peroxymonosulfate to complete the degradation of the organic pollutants in the water bodies. Finally, the three-dimensional aerogel composite material is taken out with a pair of tweezers and washed for reuse. The three-dimensional aerogel composite material comprises iron-doped carbon nitride and gelatin aerogel, and the iron-doped carbon nitride is uniformly distributed in the gelatin aerogel. The method for removing organic pollutants in water bodies by using the three-dimensional aerogel composite material has the advantages of simple treatment process, convenient operation, low cost, high treatment efficiency, good removal effect, high reuse rate and cleanness and no pollution, is a treatment method which can be widely used and can efficiently remove organic pollutants, and has high application value and commercial value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of water body treatment containing organic pollutants, and relates to a method for treating organic pollutants in a water body, in particular to a method for removing organic pollutants in a water body by using a three-dimensional aerogel composite material. BACKGROUND

[0002] Persulfate (HSO5 - , PMS) as a stable strong oxidant (E0=1.82V) has been increasingly applied to remove environmental organic pollutants such as pharmaceuticals and personal care products (PPCPs), endocrine disruptors (EDCs) and dyes. The O-O bond in persulfate can be broken to produce reactive oxygen species, thereby effectively degrading various refractory organic pollutants. Transition metal ions (such as Fe, Ni, Co, Mn) can activate persulfate and produce reactive oxygen species through an electron transfer process. Metal-organic framework materials (MOFs) are a kind of crystalline materials that can be prepared by self-assembly of transition metal ions / clusters and organic linkers. Due to the weak stability between metal nodes and organic linkers, most metal-organic framework materials are unstable in water, which limits the practical application of metal-organic framework materials. Through the calcination process under inert gas atmosphere, the organic ligand of metal-organic framework material can be converted into a carbon matrix doped with nitrogen atoms, while the metal nodes can be converted into metal nanoparticles in the carbon matrix. The metal nanoparticles embedded in the carbon matrix can exhibit a synergistic effect, thereby improving the performance and stability of catalytic persulfate. However, the metal-organic framework material derivatives are still in the form of powder, which is difficult to recover in liquid phase catalysis.

[0003] Aerogel (AG) is a three-dimensional interconnected solid network structure with more than 90% air, which has become a new type of porous material with high specific surface area. The three-dimensional interconnected aerogel structure provides an effective method for loading metal-organic framework material-based nanoparticles with outstanding performance. However, due to the unstable thermodynamic parameters triggering the inevitable agglomeration of metal-organic framework material-based nanoparticles and the collapse of the aerogel pore structure caused thereby, the overall catalytic activity and recyclability will be affected. Therefore, the synthesis method and template selection are still a major challenge to manufacture metal-organic framework material-based nanoparticles with a well-interconnected three-dimensional network structure. How to comprehensively improve the existing problems and deficiencies in the three-dimensional aerogel composite material, and obtain an aerogel composite material with good three-dimensional network internet structure, stable performance, high catalytic activity and easy recycling and reuse, is of great significance for improving the application range of the aerogel composite material in the treatment of water bodies containing organic pollutants. SUMMARY

[0004] The technical problem solved by the present application is to overcome the shortcomings of the prior art and provide a method for removing organic pollutants in water bodies using three-dimensional aerogel composite materials, which has good removal effect, high reuse rate and is clean and pollution-free.

[0005] To solve the above technical problems, the present application adopts the following technical solutions:

[0006] A method for removing organic pollutants in water bodies using three-dimensional aerogel composite materials, characterized by comprising the following steps: oscillating and mixing adsorption of three-dimensional aerogel composite materials and water bodies containing organic pollutants, then adding a certain amount of persulfate to complete the degradation of organic pollutants in the water body. Finally, the three-dimensional aerogel composite material is taken out with tweezers and washed for reuse. The three-dimensional aerogel composite material comprises iron-doped carbon nitride and gelatin aerogel, and the iron-doped carbon nitride is uniformly distributed in the gelatin aerogel.

[0007] The above method is further improved, and the specific surface area of the three-dimensional aerogel composite material is 7.9276m 2 / g.

[0008] The above method is further improved, and the preparation method of the three-dimensional aerogel composite material comprises the following steps:

[0009] S1, zinc nitrate hexahydrate, iron nitrate nonahydrate and dimethyl imidazole are dissolved in deionized water;

[0010] S2, slowly add the mixed solution of zinc nitrate hexahydrate and iron nitrate nonahydrate in step S1 to the dimethyl imidazole solution and stir to obtain a yellow self-sacrificing template (iron-doped zeolite imidazole framework, Fe-ZIF-L);

[0011] S3, the yellow self-sacrificing template is calcined in a nitrogen atmosphere to obtain iron-doped carbon nitride;

[0012] S4, gelatin and sodium dodecyl sulfonate are dissolved in deionized water, and the iron-doped carbon nitride obtained in step S3 is mixed uniformly and then stirred rapidly to obtain a dense foam;

[0013] S5, freeze-drying and low-temperature calcination of the foam obtained in step S4 to obtain a three-dimensional aerogel composite material.

[0014] The above method is further improved, and the molar ratio of zinc nitrate hexahydrate, iron nitrate nonahydrate and dimethyl imidazole is 1:1:8, and the deionized water is 40mL.

[0015] The above method is further improved, and in step S2, the stirring speed is 100r / min-200r / min; the stirring time is 4 hours.

[0016] The stirring after the iron-doped zeolitic imidazolate framework is obtained further comprises the following steps: centrifugation, washing and drying of the product generated after the stirring. The rotation speed of the centrifugation is 3000 r / min-5000 r / min; the washing uses deionized water; the number of washing is 3-5 times; the drying is performed under vacuum; the drying temperature is 60℃-100℃; and the drying time is 8-12 hours.

[0017] The above method is further improved, and in step S3, the initial temperature of the calcination reaction is 10℃-30℃, the heating rate is 5℃ / min, heating to 800℃ in a nitrogen atmosphere and keeping for 2 hours, and then natural cooling.

[0018] The above method is further improved, and in step S3, the initial temperature of the calcination reaction is 10℃-30℃, the heating rate is 5℃ / min, heating to 800℃ in a nitrogen atmosphere and keeping for 2 hours, and then natural cooling.

[0019] The above method is further improved, and in step S4, the dosing amount of the gelatin and sodium dodecyl sulfonate is 0.38 g and 0.0142 g respectively, and the deionized water is 5 mL. The loaded iron-doped carbon nitride is 0.15 g, which is first mixed uniformly by magnetic stirring, the rotation speed of the stirring is 100 r / min-200 r / min, and the stirring time is 1 hour. Subsequently, a dense foam is formed by rapid stirring, the rotation speed of the stirring is 1500 r / min-2000 r / min, and the stirring time is 15 minutes.

[0020] The above method is further improved, and in step S5, the pressure of the freeze-drying is 7-8 kPa, the temperature of the freeze-drying is -40℃--50℃, and the time of the freeze-drying is 12-20 hours. The initial temperature of the calcination reaction is 10℃-30℃, the heating rate is 5℃ / min, heating to 150℃ in a nitrogen atmosphere and keeping for 3 hours, and then natural cooling.

[0021] The above method is further improved, and in step S5, the pressure of the freeze-drying is 7-8 kPa, the temperature of the freeze-drying is -40℃--50℃, and the time of the freeze-drying is 12-20 hours. The initial temperature of the calcination reaction is 10℃-30℃, the heating rate is 5℃ / min, heating to 150℃ in a nitrogen atmosphere and keeping for 3 hours, and then natural cooling.

[0022] The above method is further improved, and the volume of the water body containing organic pollutants degraded by the three-dimensional aerogel composite material is 0.1 L.

[0023] The method is further improved, and the organic pollutants in the water body containing the organic pollutants are rhodamine B, tetracycline hydrochloride, doxycycline, aureomycin, oxytetracycline, levofloxacin, ciprofloxacin, norfloxacin and sulfadimidine; the concentration of the organic pollutants in the water body containing the organic pollutants is 20 mg / L to 30 mg / L; and the pH of the water body containing the organic pollutants is 2 to 12.

[0024] The method is further improved, and the rotation speed of the oscillation adsorption is 200 r / min to 300 r / min; and the oscillation adsorption time is 30 minutes.

[0025] The method is further improved, and after the oscillation adsorption is completed, the following treatment is further included: a certain amount of persulfate (PMS) is added to catalytically degrade the reaction product after the oscillation adsorption is completed; and the catalytic reaction time is 0.5 hours; and the persulfate addition amount is 0.3 g / L.

[0026] The method is further improved, and after the catalytic reaction is completed, the three-dimensional aerogel composite material is taken out by using tweezers and washed with deionized water, so that the three-dimensional aerogel composite material can be reused; and the washing frequency is 3 to 5 times.

[0027] Compared with the prior art, the method has the following advantages:

[0028] (1) The method for removing organic pollutants in water by using a three-dimensional aerogel composite material is provided. The gelatin molecular chain contains rich hydroxyl groups, carboxyl groups and amino groups, and is easy to gelate and functionalize, and can be used to prepare a three-dimensional aerogel. The iron-doped carbon nitride with catalytic activity is uniformly distributed in the three-dimensional aerogel by a sol-gel method. The three-dimensional aerogel composite material is mixed with the water body containing the organic pollutants to perform oscillation adsorption, a certain amount of persulfate is added to the suspension liquid after the adsorption balance is reached to perform a catalytic degradation reaction, and the organic pollutants in the water body can be efficiently degraded. The method has the advantages of simple treatment process, convenient operation, simple equipment, low cost, green environmental protection, high treatment efficiency, good removal effect, high reuse rate, cleanliness and no pollution, and can be widely used to efficiently remove the organic pollutants in the water body, and has high application value and commercial value.

[0029] (2) The three-dimensional aerogel composite material adopted in the application comprises iron-doped carbon nitride and gelatin aerogel, and the iron-doped carbon nitride is uniformly distributed in the gelatin aerogel. The gelatin aerogel has the advantages of low density and good three-dimensional compressibility, and is easy to separate from an aqueous solution, thereby reducing secondary pollution and improving the cycle performance. The iron-doped carbon nitride can act as a mechanical support skeleton and provide catalytic sites to activate the degradation of various organic pollutants in the aqueous solution by persulfate (PMS), and the iron-doped carbon nitride embedded therein effectively inhibits its inherent aggregation and fully exposes the active sites. The synthesized three-dimensional aerogel composite material has a hierarchical pore structure (large pores, mesopores and micropores), which greatly reduces the diffusion resistance of pollutants. Compared with the prior art, the three-dimensional aerogel composite material has the advantages of good stability, high catalytic activity, easy recycling, green environmental protection and the like, can realize efficient degradation of organic pollutants, and has good application prospect.

[0030] (3) In the application, the influencing factors of the three-dimensional aerogel composite material catalyzing the persulfate system are explored. By exploring the loading amount of the iron-doped carbon nitride and the initial pH value of tetracycline hydrochloride, the performance of the three-dimensional aerogel composite material is optimized. In addition, the performance of the three-dimensional aerogel composite material in catalyzing and degrading other typical organic pollutants such as rhodamine B, tetracycline hydrochloride, doxycycline, aureomycin, terramycin, levofloxacin, ciprofloxacin, norfloxacin and sulfadimidine is explored. Therefore, the reaction conditions of the three-dimensional aerogel composite material for removing organic pollutants are optimized, and a large number of attempts are made for degrading different types of pollutants, which has important significance for promoting the wide application of the three-dimensional aerogel composite material.

[0031] (4) In the application, the recycling and dynamic catalytic degradation performance of the three-dimensional aerogel composite material are explored. The three-dimensional aerogel composite material can be reused only by taking it out with tweezers and washing it with deionized water. The material after the degradation reaction can be recycled. The method for removing organic pollutants in water by using the three-dimensional aerogel composite material has the advantages of simple operation, good removal effect, simple recovery, high recycling rate and the like, and has wide application prospect in industrial application. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below in combination with the drawings in the embodiments of the application.

[0033] Figure 1 The micro-morphology diagrams of the three-dimensional aerogel (AG) and the three-dimensional aerogel composite material (Fe@NC-0.15 / AG) prepared in the embodiment 1 of the application, wherein (a) and (b) are scanning electron microscope diagrams of the three-dimensional aerogel, and (c) and (d) are scanning electron microscope diagrams of the three-dimensional aerogel composite material.

[0034] Figure 2 X-ray diffraction patterns of different iron-doped carbon nitride loadings of three-dimensional aerogel composite materials (Fe@NC-0.05 / AG, Fe@NC-0.1 / AG, Fe@NC-0.15 / AG, and Fe@NC-0.2 / AG) and three-dimensional aerogel (AG) in Example 1 of the present application.

[0035] Figure 3 Catalytic degradation of tetracycline hydrochloride by different iron-doped carbon nitride loadings of three-dimensional aerogel composite materials (Fe@NC-0.05 / AG, Fe@NC-0.1 / AG, Fe@NC-0.15 / AG, and Fe@NC-0.2 / AG) and three-dimensional aerogel (AG) in Example 1 of the present application under the addition of persulfate.

[0036] Figure 4 Catalytic degradation of tetracycline hydrochloride by different pH values of tetracycline hydrochloride solution by three-dimensional aerogel composite materials (Fe@NC-0.15 / AG) in Example 2 of the present application and the corresponding zeta potential diagrams.

[0037] Figure 5 Cyclic recovery effect of tetracycline hydrochloride by three-dimensional aerogel composite materials (Fe@NC-0.15 / AG) in Example 3 of the present application.

[0038] Figure 6 Dynamic degradation effect of tetracycline hydrochloride by three-dimensional aerogel composite materials (Fe@NC-0.15 / AG) in Example 4 of the present application. Wherein (a) is a dynamic degradation device diagram, and (b) is a degradation effect diagram.

[0039] Figure 7 Degradation effect of tetracycline hydrochloride in different actual water samples by three-dimensional aerogel composite materials (Fe@NC-0.15 / AG) in Example 5 of the present application.

[0040] Figure 8 Catalytic degradation of different organic pollutants by three-dimensional aerogel composite materials (Fe@NC-0.15 / AG) in Example 6 of the present application. DETAILED DESCRIPTION

[0041] The present application is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of protection of the present application is not limited thereby.

[0042] The raw materials and instruments used in the following examples are commercially available. In the following examples, the obtained data are the average values of more than three repeated experiments, unless otherwise specified.

[0043] Example 1

[0044] A method for removing organic pollutants in water bodies by using three-dimensional aerogel composite material, specifically, using three-dimensional aerogel composite material to catalytically degrade tetracycline hydrochloride in water bodies, comprising the following steps:

[0045] A piece of three-dimensional aerogel composite material (Fe@NC-0.05 / AG, Fe@NC-0.1 / AG, Fe@NC-0.15 / AG and Fe@NC-0.2 / AG) and three-dimensional aerogel (AG) are added to 100 mL of tetracycline hydrochloride solution with a concentration of 5 parts of 30 mg / L, and oscillation adsorption is carried out at a rotation speed of 200 r / min for 30 minutes. After reaching adsorption equilibrium, 0.3 g / L of persulfate is added, and the effect of different loadings of iron-doped carbon nitride on the catalytic degradation of tetracycline hydrochloride by three-dimensional aerogel composite material is investigated.

[0046] In this embodiment, the preparation method of the three-dimensional aerogel composite material (Fe@NC-0.15 / AG) used is as follows: zinc nitrate hexahydrate, iron nitrate nonahydrate and dimethyl imidazole are used as raw materials, and iron-doped carbon nitride is prepared by room temperature stirring self-crystallization and inert gas calcination. Then the iron-doped carbon nitride is loaded into a gelatin solution, and a three-dimensional aerogel composite material (Fe@NC-0.15 / AG) is obtained by sol-gel method and subsequent freeze-drying and low-temperature calcination technology, comprising the following steps:

[0047] (1) Dissolve zinc nitrate hexahydrate and iron nitrate nonahydrate in 40 mL of deionized water, and dissolve dimethyl imidazole in 40 mL of deionized water, wherein the molar ratio of zinc nitrate hexahydrate, iron nitrate nonahydrate and dimethyl imidazole is 1:1:8. Slowly add the mixed solution of zinc nitrate hexahydrate and iron nitrate nonahydrate to the dimethyl imidazole solution and stir at a rotation speed of 100 r / min to 200 r / min for 4 hours to obtain a yellow self-sacrificial template (iron-doped zeolitic imidazole framework, Fe-ZIF-L). Centrifuge, wash and dry the yellow self-sacrificial template, centrifuge at a rotation speed of 3000 r / min to 5000 r / min, wash with deionized water for 3 to 5 times, and then vacuum dry at 60°C to 100°C for 8 to 12 hours.

[0048] (2) The obtained iron-doped zeolitic imidazolate framework powder is calcined in a nitrogen atmosphere, the initial temperature of the calcination reaction is 10-30°C, the heating rate is 5°C / min, heated to 800°C in a nitrogen atmosphere and kept for 2 hours, and then naturally cooled. After the completion of the calcination reaction, the reaction product obtained after the completion of the calcination reaction is washed by centrifugation 3-5 times with deionized water, the rotation speed of centrifugation is 3000-5000 r / min. Finally, vacuum drying is performed, the drying temperature is 60-100°C, the drying time is 8-12 hours, and iron-doped carbon nitride (Fe@NC) is obtained.

[0049] (3) 0.38 g of gelatin and 0.0142 g of sodium dodecyl sulfate are dissolved in 5 mL of deionized water, 0.15 g of iron-doped carbon nitride is uniformly mixed (the rotation speed of stirring is 100-200 r / min), and then rapid stirring (the rotation speed of stirring is 1500-2000 r / min) is performed for 15 minutes to obtain a dense foam. The obtained foam is freeze-dried, the gas pressure of freeze-drying is 7-8 kPa, the temperature of freeze-drying is -40 to -50°C, and the freeze-drying time is 12-20 hours. Then, low-temperature calcination is performed, the initial temperature of the calcination reaction is 10-30°C, the heating rate is 5°C / min, heated to 150°C in a nitrogen atmosphere and kept for 3 hours, and then naturally cooled. The reaction product obtained after the completion of the calcination reaction is washed and soaked 3-5 times with deionized water, and finally a three-dimensional aerogel composite material is obtained.

[0050] In this embodiment, the preparation method of the three-dimensional aerogel composite material (Fe@NC-0.05 / AG) is basically the same as that of the three-dimensional aerogel composite material (Fe@NC-0.15 / AG), and the only difference is that the loading amount of iron-doped carbon nitride in the preparation method of the three-dimensional aerogel composite material (Fe@NC-0.05 / AG) is 0.05 g.

[0051] In this embodiment, the preparation method of the three-dimensional aerogel composite material (Fe@NC-0.1 / AG) is basically the same as that of the three-dimensional aerogel composite material (Fe@NC-0.15 / AG), and the only difference is that the loading amount of iron-doped carbon nitride in the preparation method of the three-dimensional aerogel composite material (Fe@NC-0.1 / AG) is 0.1 g.

[0052] In this embodiment, the preparation method of the three-dimensional aerogel composite material (Fe@NC-0.2 / AG) is basically the same as that of the three-dimensional aerogel composite material (Fe@NC-0.15 / AG), and the only difference is that the loading amount of iron-doped carbon nitride in the preparation method of the three-dimensional aerogel composite material (Fe@NC-0.2 / AG) is 0.2 g.

[0053] The preparation method of the three-dimensional aerogel (AG) used in this embodiment is basically the same as the preparation method of the three-dimensional aerogel composite (Fe@NC-0.15 / AG), and the only difference is that there is no loading of iron-doped carbon nitride in the preparation method of the three-dimensional aerogel (AG).

[0054] Figure 1 The micro-morphology diagrams of the three-dimensional aerogel (AG) and the three-dimensional aerogel composite (Fe@NC-0.15 / AG) prepared in Example 1 of the present application, wherein (a) and (b) are scanning electron micrographs of the three-dimensional aerogel, and (c) and (d) are scanning electron micrographs of the three-dimensional aerogel composite. The scanning electron micrographs show that the three-dimensional aerogel has smooth pore walls and larger connected pores (pore diameter of about 100 μm). Obviously, the three-dimensional aerogel composite retains the pore structure of the three-dimensional aerogel, and the iron-doped carbon nitride particles are tightly attached to the pore walls of the aerogel. Therefore, the scanning electron micrographs prove that the iron-doped carbon nitride in the three-dimensional aerogel composite is successfully loaded in the pore channels of the three-dimensional aerogel and does not affect the pore channel structure.

[0055] Figure 2 The X-ray diffraction patterns of the three-dimensional aerogel composite (Fe@NC-0.05 / AG, Fe@NC-0.1 / AG, Fe@NC-0.15 / AG and Fe@NC-0.2 / AG) with different loadings of iron-doped carbon nitride prepared in Example 1 of the present application, and the three-dimensional aerogel (AG) and the iron-doped carbon nitride (Fe@NC). The X-ray diffraction pattern of the iron-doped carbon nitride (Fe@NC) shows two peaks at 31.7° and 36.3°, which are from the (100) and (101) crystal planes of ZnO (JCPDS No. 75-0576), respectively. The peaks at 35.2° and 37.7° are FeC3 (JCPDS No. 35-0772), the peaks at 30.1°, 43.1°, 56.9° and 62.5° are magnetic Fe3O4 (JCPDS No. 73-2303), and the peak at 44.6° is metallic Fe (JCPDS No. 06-0696). The three-dimensional aerogel (AG) has a broad peak around 20°, indicating that it is an amorphous carbon structure. As can be seen from the figure, as the loading of iron-doped carbon nitride increases, the peak of the three-dimensional aerogel gradually disappears, and the peak of the iron-doped carbon nitride becomes stronger, indicating that the iron-doped carbon nitride particles are embedded in the three-dimensional aerogel.

[0056] Figure 3A graph of the catalytic degradation of tetracycline hydrochloride by different iron-doped carbon nitride loadings of three-dimensional aerogel composites (Fe@NC-0.05 / AG, Fe@NC-0.1 / AG, Fe@NC-0.15 / AG, and Fe@NC-0.2 / AG) and three-dimensional aerogels (AG) under the addition of persulfate in Example 1 of the present application. The three-dimensional aerogel composites have a porous structure, low density, and good mechanical stability, and are a promising activator of persulfate (PMS). Therefore, different amounts of iron-doped carbon nitride (0 g, 0.05 g, 0.1 g, 0.15 g, 0.2 g) were added to the three-dimensional aerogel composites to obtain the best performance of the composites. In the catalytic experiment, different iron-doped carbon nitride loadings of three-dimensional aerogel composites (Fe@NC-0.05 / AG, Fe@NC-0.1 / AG, Fe@NC-0.15 / AG, and Fe@NC-0.2 / AG) and three-dimensional aerogels (AG) were dispersed in a tetracycline hydrochloride solution (30 mg / L) and stirred for 30 minutes to reach adsorption equilibrium. Then, 0.3 g / L of persulfate was added and continuously stirred for 60 minutes. During the catalytic process, 1 mL of sample was taken every time interval (5 minutes, 10 minutes, 20 minutes, 30 minutes, 45 minutes, 60 minutes), and the sample was filtered with a 0.22 μm filter head and then 1 mL of methanol was added to quench the free radicals. The sample was determined by high performance liquid chromatography, and the removal rate was determined according to the ratio of the peak area to the original solution, thereby obtaining a graph of the catalytic degradation of tetracycline hydrochloride by different iron-doped carbon nitride loadings of three-dimensional aerogel composites and three-dimensional aerogels (AG) under the addition of persulfate, as shown in Figure 3 Figure 3 In the above table, the removal rates of tetracycline hydrochloride by pure PMS, AG / PMS, Fe@NC-0.05 / AG / PMS, Fe@NC-0.1 / AG / PMS, Fe@NC-0.15 / AG / PMS, and Fe@NC-0.2 / AG / PMS systems were 28.1%, 32.3%, 74.8%, 82.5%, 94.3%, and 95.5%, respectively. Therefore, as the content of iron-doped carbon nitride in the three-dimensional aerogel composites increased, the removal efficiency of tetracycline hydrochloride improved significantly. Since the removal rates of Fe@NC-0.15 / AG / PMS and Fe@NC-0.2 / AG / PMS systems were almost the same, the Fe@NC-0.15 / AG catalyst was selected for subsequent experiments from the perspective of cost savings.

[0057] Example 2

[0058] A method for removing organic pollutants in water using a three-dimensional aerogel composite, specifically catalytic degradation of tetracycline hydrochloride in water using a three-dimensional aerogel composite, comprising the following steps:

[0059] ​A piece of three-dimensional aerogel composite (Fe@NC-0.15 / AG) was added to 100 mL of tetracycline hydrochloride solution with a concentration of 30 mg / L and pH values of 2, 4, 6, 8, 10, and 12, respectively, and was oscillated and adsorbed for 30 minutes at a rotation speed of 200 r / min. After reaching adsorption equilibrium, 0.3 g / L of persulfate was added to explore the influence of tetracycline hydrochloride with different initial pH values on the catalytic performance of the three-dimensional aerogel composite.

[0060] In the catalytic experiment, the three-dimensional aerogel composite (Fe@NC-0.15 / AG) was dispersed in the tetracycline hydrochloride solution (30 mg / L) and stirred for 30 minutes to reach adsorption equilibrium. Then, 0.3 g / L of persulfate was added and continuously stirred for 60 minutes. During the catalytic process, 1 mL of sample was taken every time interval (5 minutes, 10 minutes, 20 minutes, 30 minutes, 45 minutes, and 60 minutes), and the sample was filtered with a 0.22 μm filter head and then 1 mL of methanol was added to quench the free radicals. The sample was determined by high performance liquid chromatography, and the removal rate was determined according to the ratio of the peak area to the original solution, so as to obtain the catalytic degradation diagram of the three-dimensional aerogel composite on tetracycline hydrochloride with different pH values under the addition of persulfate, as shown in Figure 4 When the pH values of the tetracycline hydrochloride solution were 2, 4, 6, 8, 10, and 12, respectively, the removal rates of tetracycline hydrochloride in the Fe@NC-0.15 / AG / PMS system were 74.2%, 91.1%, 89.6%, 90.7%, 92.8%, and 84.5%, respectively. Therefore, the initial pH value of the tetracycline hydrochloride solution has a certain influence on the removal efficiency of the Fe@NC-0.15 / AG / PMS system.

[0061] To illustrate the influence of pH value on the leaching of Fe ions, inductively coupled plasma mass spectrometry was used to determine the leaching of iron ions in the solution after the catalytic reaction. At the same time, the zeta potential of the three-dimensional aerogel composite (Fe@NC-0.15 / AG) in the tetracycline hydrochloride solution with different pH values was also measured. Under the conditions of pH=2, pH=4, pH=6, pH=8, pH=10, and pH=12, the leaching rates of iron ions were 3.34 mg / L, 0.035 mg / L, 0.005 mg / L, 0.003 mg / L, 0.061 mg / L, and 0.034 mg / L, respectively. At pH=2, the leaching of iron ions from the three-dimensional aerogel composite was serious, which was not conducive to the catalytic reaction, thereby reducing the removal rate. In addition, the isoelectric point of Fe@NC-0.15 / AG was 5.66( Figure 4 ) The electrostatic repulsion of the Fe@NC-0.15 / AG / PMS system under the conditions of pH=2 and pH=12 may cause the removal efficiency of tetracycline hydrochloride to be relatively low.

[0062] Example 3

[0063] A method for removing organic pollutants in water bodies by using three-dimensional aerogel composite material, specifically exploring the reusability of three-dimensional aerogel composite material for tetracycline hydrochloride degradation in water bodies, comprising the following steps:

[0064] A piece of three-dimensional aerogel composite material (Fe@NC-0.15 / AG) is added to 100 mL of tetracycline hydrochloride solution with a concentration of 30 mg / L, and oscillation adsorption is carried out at a rotation speed of 200 r / min for 30 minutes. After reaching adsorption equilibrium, 0.3 g / L of persulfate is added and continuously stirred for 60 minutes. During the catalysis process, 1 mL of sample is taken every certain time (5 minutes, 10 minutes, 20 minutes, 30 minutes, 45 minutes, and 60 minutes), and the sample is filtered with a 0.22 μm filter head and then 1 mL of methanol is added to quench the free radicals. The sample is determined by high performance liquid chromatography, and the removal rate is determined according to the ratio of the peak area to the original solution. After the completion of the catalytic reaction, the three-dimensional aerogel composite material is separated with tweezers and washed in deionized water for 3-5 times, and then it can be recycled after being squeezed dry. Figure 5 It can be seen that the removal efficiency of Fe@NC-0.15 / AG / PMS for tetracycline hydrochloride is 94.3%, and after ten cycles, the removal efficiency of the system for tetracycline hydrochloride is still 90.17%, and the removal efficiency does not decrease after ten cycles. Therefore, the three-dimensional aerogel composite material has good recycling performance. In addition, the content of iron element in Fe@NC-0.15 / AG is 8.26% determined by inductively coupled plasma mass spectrometry. After ten cycles, the iron content is 7.57%, so the three-dimensional aerogel composite material prepared in the present application has superior stability.

[0065] Example 4

[0066] A method for removing organic pollutants in water bodies by using three-dimensional aerogel composite material, specifically exploring the dynamic degradation performance of three-dimensional aerogel composite material for tetracycline hydrochloride in water bodies, comprising the following steps:

[0067] Two pieces of three-dimensional aerogel composite material (Fe@NC-0.15 / AG) are applied to an integrated filter (the experimental setup is shown in the drawing Figure 6a) The mixture solution of tetracycline hydrochloride (30 mg / L) and persulfate (0.3 g / L) was introduced into the device by a peristaltic pump, and the mixture solution passed through the three-dimensional aerogel composite filter layer under the action of gravity. The liquid flow was controlled by a peristaltic pump, and the average flow rate of this experiment was calculated to be 2.22 mL / min. 1 mL of sample was taken from the water outlet every 10 minutes, and the sample was filtered with a 0.22 μm filter head and then added with 1 mL of methanol to quench the free radicals. The sample was determined by high performance liquid chromatography, and the removal rate was determined according to the ratio of the peak area to the original solution. It can be seen from Figure 6 b that the double-layer filter can remove more than 90% of the tetracycline hydrochloride molecules after 420 minutes. The iron-doped carbon nitride particles are uniformly distributed in the pores of the three-dimensional aerogel, which greatly improves the utilization rate of the iron-doped carbon nitride catalyst. The rich channels in the three-dimensional aerogel provide sufficient contact between the iron-doped carbon nitride particles and the tetracycline hydrochloride molecules. Therefore, the dynamic degradation experiment proves that the three-dimensional aerogel composite material has potential for practical application.

[0068] Example 5

[0069] A method for removing organic pollutants in water bodies by using a three-dimensional aerogel composite material, specifically using a three-dimensional aerogel composite material to catalytically degrade tetracycline hydrochloride in different water bodies, comprising the following steps:

[0070] 1 L of tetracycline hydrochloride solution with a concentration of 30 mg / L was prepared using deionized water, tap water (pH = 7.13, total organic carbon 0.603 mg / L), Xiangjiang River water (pH = 7.67, total organic carbon 22.61 mg / L), and medical waste water (pH = 7.72, total organic carbon 64.23 mg / L) as solvents. Four pieces of three-dimensional aerogel composite material (Fe@NC-0.15 / AG) were added to 100 mL of tetracycline hydrochloride solution with a concentration of 30 mg / L prepared from different water samples, and oscillated for 30 minutes under the condition of a rotation speed of 200 r / min. After reaching adsorption equilibrium, 0.3 g / L of persulfate was added to explore the performance of the three-dimensional aerogel composite material in catalytically degrading tetracycline hydrochloride in different water bodies.

[0071] In the catalytic experiment, the three-dimensional aerogel composite material (Fe@NC-0.15 / AG) was dispersed in the tetracycline hydrochloride solution (30 mg / L) prepared with different water samples and stirred for 30 minutes to reach adsorption equilibrium. Then 0.3 g / L of persulfate was added and continuously stirred for 60 minutes. During the catalysis process, 1 mL of sample was taken every time interval (5 minutes, 10 minutes, 20 minutes, 30 minutes, 45 minutes, 60 minutes), and the sample was filtered with a 0.22 μm filter head and then 1 mL of methanol was added to quench the free radicals. The sample was determined by high performance liquid chromatography, and the removal rate was determined according to the ratio of the peak area to the original solution, so as to obtain the catalytic degradation diagram of the three-dimensional aerogel composite material on tetracycline hydrochloride in water with the addition of persulfate, as shown in Figure 7 The removal rates of Fe@NC-0.15 / AG / PMS system on tetracycline hydrochloride in deionized water, tap water, Xiangjiang River water and medical waste water were 94.3%, 90.2%, 89.5% and 88.4%, respectively.

[0072] Example 6

[0073] A method for removing organic pollutants in water by using a three-dimensional aerogel composite material, specifically using a three-dimensional aerogel composite material to catalytically degrade typical organic pollutants (such as rhodamine B, tetracycline hydrochloride, doxycycline, aureomycin, terramycin, levofloxacin, ciprofloxacin, norfloxacin, sulfadimethoxine) in water, comprising the following steps:

[0074] Nine pieces of three-dimensional aerogel composite material (Fe@NC-0.15 / AG) were added to 100 mL of rhodamine B, tetracycline hydrochloride, doxycycline, aureomycin, terramycin, levofloxacin, ciprofloxacin, norfloxacin, sulfadimethoxine solution with a concentration of 20 mg / L, and oscillated for adsorption at a speed of 200 r / min for 30 minutes. After reaching adsorption equilibrium, 0.3 g / L of persulfate was added and continuously stirred for 60 minutes. During the catalysis process, 1 mL of sample was taken every time interval (5 minutes, 10 minutes, 20 minutes, 30 minutes, 45 minutes, 60 minutes), and the sample was filtered with a 0.22 μm filter head and then 1 mL of methanol was added to quench the free radicals. The sample was determined by high performance liquid chromatography, and the removal rate was determined according to the ratio of the peak area to the original solution. Thus, the degradation of the three-dimensional aerogel composite material catalytic persulfate system on typical organic pollutants in water was obtained, as shown in Figure 8 Figure 8 ​It can be known that the removal rates of the three-dimensional aerogel composite material catalytic persulfate system on rhodamine B, tetracycline hydrochloride, doxycycline, aureomycin, terramycin, levofloxacin, ciprofloxacin, norfloxacin and sulfadimidine are 99.7%, 94.3%, 92.2%, 94.0%, 92.8%, 95.6%, 94.9%, 91.1% and 98.0% respectively. Therefore, the three-dimensional aerogel composite material coupled with the persulfate system has good removal effect on typical organic pollutants in water.

[0075] Therefore, the method for removing organic pollutants in water by using the three-dimensional aerogel composite material can efficiently degrade the organic pollutants in the solution by mixing the three-dimensional aerogel composite material with the organic pollutant solution, oscillating and adding the persulfate, and has the advantages of simple treatment process, convenient operation, simple equipment, low cost, green environmental protection, high treatment efficiency, good removal effect, high reuse rate, clean and no pollution, and the like. The method can be widely used, efficiently removes the organic pollutants, has high application value and commercial value, and is a processing method with high application value and commercial value.

[0076] The above examples are only preferred embodiments of the present application, and the protection scope of the present application is not limited to the above examples. Any technical scheme falling within the concept of the present application belongs to the protection scope of the present application. It should be pointed out that improvements and refinements made by ordinary skilled in the art without departing from the principles of the present application should also be considered as the protection scope of the present application.

Claims

1. A method for removing organic pollutants from a water body using a three-dimensional aerogel composite material, characterized in that, The method comprises the following steps: The three-dimensional aerogel composite material is mixed with water body containing organic pollutants by oscillation adsorption, a certain amount of peroxymonosulfate is added, and the catalytic degradation of the organic pollutants in the water body is completed; finally, the three-dimensional aerogel composite material is taken out with a pair of tweezers and washed to be reused; the three-dimensional aerogel composite material comprises iron-doped carbon nitride and gelatin aerogel, the iron-doped carbon nitride is uniformly distributed in the gelatin aerogel, and the specific surface area of the three-dimensional aerogel composite material is 7.9276 m 2 / g, and the preparation process comprises the following steps: S1, zinc nitrate hexahydrate, iron nitrate nonahydrate and dimethyl imidazole are dissolved in deionized water; S2, the mixed solution of zinc nitrate hexahydrate and iron nitrate nonahydrate in step S1 is slowly added into the dimethyl imidazole solution and stirred to obtain a yellow self-sacrificing template, and the yellow self-sacrificing template is an iron-doped zeolitic imidazolate framework; S3, the yellow self-sacrificing template is calcined in a nitrogen atmosphere to obtain an iron-doped carbon nitride; S4, gelatin and sodium dodecyl sulfate are dissolved in deionized water, and the iron-doped carbon nitride obtained in step S3 is uniformly mixed and then rapidly stirred to obtain a dense foam; S5, the foam obtained in step S4 is freeze-dried and low-temperature calcined to finally obtain a three-dimensional aerogel composite material.

2. The method for removing organic pollutants from water bodies using three-dimensional aerogel composites according to claim 1, characterized in that, In step S1, the molar ratio of zinc nitrate hexahydrate, iron nitrate nonahydrate and dimethyl imidazole is 1:1:8, and the deionized water is 40 mL.

3. The method for removing organic pollutants from water bodies using three-dimensional aerogel composites as claimed in claim 1, wherein, In step S2, the stirring speed is 100 r / min-200 r / min, and the stirring time is 4 hours; after the stirring to obtain the iron-doped zeolitic imidazolate framework, the following steps are further included: centrifuging, washing and drying the product generated after the stirring; the centrifuging speed is 3000 r / min-5000 r / min; the washing is performed with deionized water, and the washing frequency is 3-5 times; the drying is performed under vacuum, the drying temperature is 60-100 DEG C, and the drying time is 8-12 hours.

4. The method for removing organic pollutants from water bodies using three-dimensional aerogel composites as claimed in claim 1, wherein, In step S3, the initial temperature of the calcination reaction is 10-30 DEG C, the heating rate is 5 DEG C / min, the temperature is heated to 800 DEG C in a nitrogen atmosphere and kept for 2 hours, and then naturally cooled; after the completion of the calcination reaction, the following steps are further included: washing, magnetically recovering and drying the reaction product obtained after the completion of the calcination reaction; the washing is performed with deionized water, and the washing frequency is 3-5 times; the drying is performed under vacuum, the drying temperature is 60-100 DEG C, and the drying time is 8-12 hours.

5. The method for removing organic pollutants from water bodies using three-dimensional aerogel composites as claimed in claim 1, wherein, In step S4, the dosing amount of gelatin and sodium dodecyl sulfate is 0.38 g and 0.0142 g respectively, the deionized water is 5 mL, and the loaded iron-doped carbon nitride is 0.15 g; first, the stirring is uniformly mixed, the stirring speed is 100 r / min-200 r / min, and the stirring time is 1 hour; then, the rapid stirring forms a dense foam, the stirring speed is 1500 r / min-2000 r / min, and the stirring time is 15 minutes.

6. The method for removing organic pollutants from water bodies using three-dimensional aerogel composites as claimed in claim 1, wherein, In step S5, the freeze-drying pressure is 7-8 kPa, the freeze-drying temperature is -40 DEG C to -50 DEG C, and the freeze-drying time is 12-20 hours; the initial temperature of the low-temperature calcination is 10-30 DEG C, the heating rate is 5 DEG C / min, the temperature is heated to 150 DEG C in a nitrogen atmosphere and kept for 3 hours, and then naturally cooled; after the completion of the low-temperature calcination, the following steps are further included: washing and soaking the product obtained after the completion of the low-temperature calcination, and the washing is performed with deionized water, and the washing frequency is 3-5 times.

7. The method for removing organic pollutants from water bodies using three-dimensional aerogel composites as claimed in claim 1, wherein, The three-dimensional aerogel composite removes an organic pollutant-containing water volume of 0.1 L; the organic pollutant in the organic pollutant-containing water is rhodamine B, tetracycline hydrochloride, doxycycline, aureomycin, terramycin, levofloxacin, ciprofloxacin, norfloxacin, sulfadimidine; the concentration of the organic pollutant in the organic pollutant-containing water is 20 mg / L to 30 mg / L; the pH of the organic pollutant-containing water is 2 to 12; the rotation speed of the oscillation mixing adsorption is 200 r / min to 300 r / min; and the oscillation mixing adsorption time is 30 minutes.

8. The method for removing organic pollutants from water bodies using three-dimensional aerogel composites as claimed in claim 1, wherein, After the oscillation mixing adsorption is completed, the following treatment is further included: a certain amount of peroxymonosulfate is added to catalytically degrade the water after the oscillation mixing adsorption is completed, the catalytic degradation reaction time is 0.5 hours, and the peroxymonosulfate addition amount is 0.3 g / L.

9. The method for removing organic pollutants from water bodies using three-dimensional aerogel composites as claimed in claim 1, wherein, After the catalytic degradation reaction is completed, the three-dimensional aerogel composite is taken out with a pair of tweezers and washed for reuse, deionized water is used for washing, and the washing frequency is 3 to 5 times.

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