Bamboo activated carbon for degrading water-phase antibiotics by activating persulfate and preparation method of bamboo activated carbon

Abstract

The invention discloses bamboo activated carbon for degrading water-phase antibiotics by activating persulfate and a preparation method of the bamboo activated carbon, and belongs to the technical field of activated carbon materials and water treatment. The preparation method comprises the following steps: crushing, screening and drying bamboo wood, and mixing the bamboo wood with an activating reagent to obtain a mixture; carrying out ultrasonic immersion treatment on the mixture, and carrying out temperature-controlled and atmosphere-controlled pyrolysis to obtain a pyrolytic carbon material; and etching the pyrolytic carbon material by using acid, washing with water, and drying to obtain the bamboo activated carbon for activating persulfate to degrade water-phase antibiotics. According to the preparation method disclosed by the invention, activation pore-forming and multi-component doping modification are synchronously realized by adopting a one-pot method, the sulfur and nitrogen co-doped bimetallic loaded bamboo activated carbon is prepared and is used for activating persulfate to efficiently degrade organic pollutants, and efficient removal of the organic pollutants in water is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of activated carbon materials and water treatment, and particularly relates to a bamboo activated carbon for activating persulfate to degrade antibiotics in water and a preparation method thereof. BACKGROUND

[0002] Antibiotics have irreplaceable role in disease treatment and are widely used in the prevention and treatment of human and animal diseases and animal feeding additives. However, since antibiotics cannot be completely absorbed by the body, antibiotics form a continuous input and persistent existence in the environmental system, which seriously threatens human health and the stability of the ecological environment. Antibiotics are complex and difficult to degrade, and traditional water treatment technologies cannot effectively remove antibiotics. Therefore, it is urgent to reasonably and effectively remove antibiotic wastewater indicators. Therefore, it is of great significance to develop an economic, efficient, green and environmentally friendly antibiotic deep treatment technology.

[0003] Antibiotic treatment technologies mainly include adsorption method, biological treatment method and advanced oxidation method, among which the advanced oxidation method is considered an important technology for removing antibiotics in water due to its high efficiency and low cost. In recent years, advanced oxidation technology based on persulfate has received extensive attention. Persulfate is used as an initiator to produce active substances, which can efficiently decompose refractory pollutants in water. The methods for activating persulfate mainly include ultraviolet light, light, heat, transition metals and catalysts. Iron-based materials and carbon-based materials are widely used in the activation of persulfate to degrade pollutants, but these two materials have problems such as limited active sites, poor catalytic performance and difficult recovery when used alone. Iron-carbon composites can exhibit synergistic effects of iron-based materials and carbon-based materials and exhibit superior catalytic performance beyond single metal and carbon materials, and are a research hotspot. The selection of iron / carbon materials, the construction of active sites and the modification of materials are the main ways to improve the degradation performance of iron / carbon composites.

[0004] At present, the main preparation methods of carbon-based composite materials for activating persulfate are activation followed by modification or doping of chemical reagents by impregnation method, etc. These methods have the characteristics of complicated preparation process, influence of modification on specific surface properties, clustering of loaded materials caused by chemical impregnation, poor dispersion of active sites, etc., which further leads to poor catalytic degradation performance of carbon-based composite materials and needs to be improved in application effect. SUMMARY

[0005] One technical problem this invention aims to solve is to provide a method for preparing bamboo activated carbon for the activation of persulfate-degrading aqueous antibiotics. This method simultaneously achieves biomass activation into char, iron / copper bimetallic loading, and sulfur / nitrogen heteroatom co-doping in a one-pot process, resulting in bamboo activated carbon for the activation of persulfate-degrading aqueous antibiotics. The process is simple. Another technical problem this invention aims to solve is to provide bamboo activated carbon for the activation of persulfate-degrading aqueous antibiotics, with a specific surface area reaching 932 m². 2 / g, with a sulfur content of 2.65%, a nitrogen content of 3.14%, an Fe content of 4.31%, and a Cu content of 1.26%. Another technical problem to be solved by this invention is to provide an application of bamboo activated carbon in the activation of persulfate degradation to remove antibiotics from wastewater. This bamboo activated carbon has outstanding activation and degradation performance of tetracycline, up to 97.6%.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics includes the following steps:

[0008] (1) Bamboo is crushed, sieved and dried to obtain dried bamboo chips;

[0009] (2) Mix the bamboo shavings obtained in step (1) with the activating reagent to obtain a mixture;

[0010] (3) The mixture obtained in step (2) above is subjected to ultrasonic impregnation treatment and then subjected to temperature-controlled and atmosphere-controlled pyrolysis to obtain pyrolytic carbon material;

[0011] (4) The pyrolytic carbon material obtained in step (3) above is acid etched, and after etching, it is washed with water and dried to obtain bamboo activated carbon that has been activated to degrade aqueous antibiotics by persulfate.

[0012] The method uses a mixed activating agent solution with a concentration of 25-50 g / L, composed of ferric sulfate solution and copper sulfate solution, which catalytically activates carbon and introduces iron and copper loading; sulfate ions provide dopant sulfur; the mass ratio of ferric sulfate to copper sulfate is 4:1-9:1; the impregnation time is 60 min; preferably, the concentration of the mixed activating agent solution is 40-50 g / L; more preferably, the concentration of the mixed activating agent solution is 40-50 g / L, and the mass ratio of ferric sulfate to copper sulfate is 8:1-9:1; even more preferably, the concentration of the mixed activating agent solution is 50 g / L, and the mass ratio of ferric sulfate to copper sulfate is 8:1.

[0013] In the method described above, the mass ratio of the activating reagent to the dried bamboo shavings raw material is 1:10 to 1:20; preferably, the mass ratio is 1:10 to 1:12.5; and even more preferably, the mass ratio is 1:10.

[0014] The method, specifically the temperature-controlled and atmosphere-controlled pyrolysis process, involves: activating at 400-550 °C for 30-90 min under a nitrogen atmosphere, followed by further activation at 750-850 °C for 30-60 min under an ammonia-nitrogen mixed atmosphere; the ammonia volume content in the mixed atmosphere is 1%-10%; preferably, activating at 400-500 °C for 30-90 min under a nitrogen atmosphere, followed by further activation at 750-850 °C for 30-60 min under an ammonia-nitrogen mixed atmosphere; the ammonia volume content in the mixed atmosphere is 5%-10%; more preferably, activating at 450-500 °C for 30-40 min under a nitrogen atmosphere, followed by further activation at 800-850 °C for 60 min under an ammonia-nitrogen mixed atmosphere; the ammonia volume content in the mixed atmosphere is 8%-10%; and even more preferably, activating at 500 °C for 40 min under a nitrogen atmosphere... After 60 min, the temperature was further increased to 800 °C for 60 min under an ammonia-nitrogen mixed atmosphere; the volume content of ammonia in the mixed atmosphere was 8%.

[0015] In the method described above, the acid used for acid etching of the carbon material after pyrolysis is hydrochloric acid with a mass concentration of 1% to 10%.

[0016] The bamboo activated carbon prepared by the above method.

[0017] The bamboo activated carbon described herein has a specific surface area of ​​801~932 m². 2 / g, sulfur content is 1.27%~2.65%, nitrogen content is 0.78%~3.31%, Fe content is 1.89%~4.31%, and Cu content is 0.52%~1.26%; preferably, the specific surface area of ​​the activated carbon is 801~932 m² / g. 2 / g, with a sulfur content of 2.35%~2.65%, a nitrogen content of 2.52%~3.31%, an Fe content of 2.35%~4.31%, and a Cu content of 0.71%~1.26%; further preferably, the specific surface area of ​​the activated carbon is 845~932 m². 2 / g, sulfur content is 2.35%~2.65%, nitrogen content is 3.14%~3.31%, Fe content is 3.49%~4.31%, and Cu content is 1.02%~1.26%; further preferably, the specific surface area of ​​the activated carbon is 932 m². 2 / g, sulfur content is 2.65%, nitrogen content is 3.14%, Fe content is 4.31%, and Cu content is 1.26%.

[0018] The application of the above-mentioned bamboo activated carbon in activating persulfate degradation of aqueous antibiotics is as follows: bamboo activated carbon and persulfate are added to an aqueous phase containing antibiotics, and the mixture is stirred to obtain a mixed solution; the pH of the mixed solution is adjusted to activate degradation.

[0019] In the application, the antibiotic is tetracycline, and the persulfate is one or more of sodium persulfate, ammonium persulfate, or potassium persulfate.

[0020] In the aforementioned application, the aqueous phase contains 20 mg / L tetracycline. Bamboo activated carbon and persulfate are added to the above solution. 10-50 mg of bamboo activated carbon and 0.1-1.0 mM of persulfate are added per 100 mL of the above aqueous solution. The pH is adjusted to 3-10, and the solution is activated and degraded at 25-50 °C for 2 h. Alternatively, the aqueous phase contains 20 mg / L tetracycline. Bamboo activated carbon and persulfate are added to the above solution. 20 mg of bamboo activated carbon and 0.5 mM of persulfate are added per 100 mL of the above aqueous solution. The pH is adjusted to 3-7, and the solution is activated and degraded at 25-45 °C for 2 h.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0022] This invention utilizes the selection and combination of activators, with ferric sulfate and copper sulfate as activators and metal dopants, to generate a porous structure and introduce iron and copper during the pyrolysis of bamboo chips, thereby achieving iron and copper bimetallic loading on the carbon material surface and enhancing its degradation activity. Sulfate is used as a sulfur dopant to introduce sulfur onto the carbon material surface. During pyrolysis, the introduction of sulfur promotes the uniform dispersion of the loaded metal on the carbon material surface, reduces agglomeration, and forms sulfur-containing functional group active sites, thereby enhancing degradation activity.

[0023] Ammonia atmosphere and controlled temperature pyrolysis enable nitrogen atom doping on the surface of carbon materials, forming new defect sites and improving the degradation performance of pollutants; hydrochloric acid etching promotes the exposure of metal sites on the surface of carbon materials.

[0024] High-performance activated bamboo activated carbon for the degradation of aqueous antibiotics by activated persulfate was prepared by simultaneously activating biomass into char, loading iron / copper bimetallic materials, and co-doping sulfur / nitrogen heteroatoms in a one-pot process. Detailed Implementation

[0025] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0026] Example 1

[0027] A method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics includes the following steps:

[0028] (1) Bamboo material is crushed, sieved to a particle size of 1~2 mm, and dried at 100 ℃ for 2 h to obtain bamboo chip raw material;

[0029] (2) Prepare a mixed activator solution with a mass concentration of 50 g / L, wherein the mass ratio of ferric sulfate to copper sulfate in the mixed activator is 4:1;

[0030] (3) Take 50 g of dried bamboo shavings, add 100 mL of a mixed activator solution with a mass concentration of 50 g / L, stir and mix evenly at room temperature, and then soak for 60 min;

[0031] (4) The mixed impregnation material was placed in a tube furnace and activated at 400 °C for 90 min at a nitrogen atmosphere with a heating rate of 10 °C / min. Then, it was further heated to 750 °C under a nitrogen atmosphere and activated for 30 min under a nitrogen atmosphere with an ammonia volume content of 5%.

[0032] (5) After activation, the nitrogen atmosphere is reduced to room temperature. The sample is taken out and acid etched for 30 min with 100 mL of 10% hydrochloric acid solution. After washing with water and drying, bamboo activated carbon with activated persulfate degradation of aqueous antibiotics is obtained.

[0033] Example 2

[0034] A method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics includes the following steps:

[0035] (1) Bamboo material is crushed, sieved to a particle size of 1~2 mm, and dried at 100 ℃ for 2 h to obtain bamboo chip raw material;

[0036] (2) Prepare a mixed activator solution with a mass concentration of 25 g / L, wherein the mass ratio of ferric sulfate to copper sulfate in the mixed activator is 4:1;

[0037] (3) Take 50 g of dried bamboo shavings, add 100 mL of a mixed activator solution with a mass concentration of 25 g / L, stir and mix evenly at room temperature, and then soak for 60 min;

[0038] (4) The mixed impregnation material was placed in a tube furnace and activated at 500 °C for 60 min at a nitrogen atmosphere with a heating rate of 10 °C / min. Then, it was further heated to 850 °C under a nitrogen atmosphere and activated for 30 min under a nitrogen atmosphere with an ammonia content of 5%.

[0039] (5) After activation, the nitrogen atmosphere is reduced to room temperature. The sample is taken out and acid etched with 100 mL of 8% hydrochloric acid solution for 30 min. After washing with water and drying, bamboo activated carbon with activated persulfate degradation of aqueous antibiotics is obtained.

[0040] Example 3

[0041] A method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics includes the following steps:

[0042] (1) Bamboo material is crushed, sieved to a particle size of 1~2 mm, and dried at 100 ℃ for 2 h to obtain bamboo chip raw material;

[0043] (2) Prepare a mixed activator solution with a mass concentration of 40 g / L, wherein the mass ratio of ferric sulfate to copper sulfate in the mixed activator is 9:1;

[0044] (3) Take 50 g of dried bamboo shavings, add 100 mL of a mixed activator solution with a mass concentration of 40 g / L, stir and mix evenly at room temperature, and then soak for 60 min;

[0045] (4) The mixed impregnation material was placed in a tube furnace and activated at 450 °C for 30 min at a nitrogen atmosphere with a heating rate of 10 °C / min. Then, it was further heated to 850 °C under a nitrogen atmosphere and activated for 60 min under a nitrogen atmosphere with an ammonia content of 10%.

[0046] (5) After activation, the nitrogen atmosphere is reduced to room temperature. The sample is taken out and acid etched with 100 mL of 10% hydrochloric acid solution for 30 min. After washing with water and drying, bamboo activated carbon with activated persulfate degradation of aqueous antibiotics is obtained.

[0047] Example 4

[0048] A method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics includes the following steps:

[0049] (1) Bamboo material is crushed, sieved to a particle size of 1~2 mm, and dried at 100 ℃ for 2 h to obtain bamboo chip raw material;

[0050] (2) Prepare a mixed activator solution with a mass concentration of 50 g / L, wherein the mass ratio of ferric sulfate to copper sulfate in the mixed activator is 8:1;

[0051] (3) Take 50 g of dried bamboo shavings, add 100 mL of a mixed activator solution with a mass concentration of 50 g / L, stir and mix evenly at room temperature, and then soak for 60 min;

[0052] (4) The mixed impregnation material was placed in a tube furnace and activated at 500 °C for 40 min at a nitrogen atmosphere by heating at 10 °C / min. Then, it was further heated to 800 °C under a nitrogen atmosphere and activated for 60 min under a nitrogen atmosphere with an ammonia content of 8%.

[0053] (5) After activation, the nitrogen atmosphere is reduced to room temperature. The sample is taken out and acid etched with 100 mL of 5% hydrochloric acid solution for 30 min. After washing with water and drying, bamboo activated carbon with activated persulfate degradation of aqueous antibiotics is obtained.

[0054] Example 5

[0055] A method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics includes the following steps:

[0056] (1) Bamboo material is crushed, sieved to a particle size of 1~2 mm, and dried at 100 ℃ for 2 h to obtain bamboo chip raw material;

[0057] (2) Prepare a mixed activator solution with a mass concentration of 30 g / L, wherein the mass ratio of ferric sulfate to copper sulfate in the mixed activator is 6:1;

[0058] (3) Take 50 g of dried bamboo shavings, add 100 mL of a mixed activator solution with a mass concentration of 30 g / L, stir and mix evenly at room temperature, and then soak for 60 min;

[0059] (4) The mixed impregnation material was placed in a tube furnace and activated at 450 °C for 60 min at a nitrogen atmosphere with a heating rate of 10 °C / min. Then, it was further heated to 750 °C under a nitrogen atmosphere and activated for 60 min under a nitrogen atmosphere with an ammonia content of 1%.

[0060] (5) After activation, the nitrogen atmosphere is reduced to room temperature. The sample is taken out and acid etched with 100 mL of 1% hydrochloric acid solution for 30 min. After washing with water and drying, bamboo activated carbon with activated persulfate degradation of aqueous antibiotics is obtained.

[0061] Comparative Example 1

[0062] Unlike Example 4, the dried bamboo shavings raw material in step (1) was activated at 800 ℃ for 60 min under a nitrogen atmosphere by heating at 10 ℃ / min. No mixed activator was added during the activation process, and the temperature and atmosphere were not controlled in stages.

[0063] Comparative Example 2

[0064] Unlike Example 4, the activation process was conducted in an uncontrolled atmosphere.

[0065] Example 6

[0066] Take 20 mg of bamboo activated carbon prepared in Examples 1-5 and Comparative Examples 1-2, add it to 100 mL of tetracycline solution with a concentration of 20 mg / L, add 0.5 mM potassium persulfate, adjust the pH of the solution to 5, and activate and degrade it at 25 ℃ for 2 h. Take samples at fixed intervals, and use a UV-Vis spectrophotometer to test and calculate the tetracycline concentration in the solution, and calculate the degradation rate after 2 h.

[0067] The specific surface area of ​​the samples was tested using a nitrogen adsorption-desorption apparatus according to the national standard GB / T 19587-2017; the S and N contents were determined using an elemental analyzer; and the Fe and Cu contents were determined using X-ray photoelectron spectroscopy (XPS).

[0068] The test results are shown in Table 1 below.

[0069] Table 1 Test Results of Examples 1-5 and Comparative Examples 1-2

[0070]

[0071] As shown in Table 1, the bamboo activated carbon prepared in Examples 1-5 of this invention exhibits outstanding activation and degradation performance of tetracycline, reaching a maximum of 96.7%. Combined with Examples 4 and Comparative Examples 1-2, it can be seen that this invention simultaneously achieves biomass activation into char, iron / copper bimetallic loading, and sulfur / nitrogen heteroatom co-doping through a one-pot method to prepare bamboo activated carbon for the degradation of aqueous antibiotics by persulfate. The process is simple and can significantly improve the efficiency of persulfate degradation of pollutants when applied to pollution control.

[0072] Example 7

[0073] The bamboo activated carbon prepared in Example 4 was used, and the following changes were made to Example 6: the initial pH value of the solution was adjusted to 3.

[0074] Example 8

[0075] The bamboo activated carbon prepared in Example 4 was used, and the following changes were made to Example 6: the initial pH value of the solution was adjusted to 7.

[0076] Example 9

[0077] The bamboo activated carbon prepared in Example 4 was used, and the following changes were made to Example 6: the initial pH value of the solution was adjusted to 9.

[0078] The test results are shown in the table below.

[0079] Table 2 Test Results

[0080]

[0081] As shown in Table 2, the bamboo activated carbon obtained by the present invention for activating persulfate to degrade aqueous antibiotics has a good pH response. Its degradation rate decreases with increasing pH value, and the degradation rate is high under acidic conditions.

[0082] Example 10

[0083] The bamboo activated carbon prepared in Example 4 was selected, and the content of Example 6 was modified as follows: the activation degradation temperature was 35 ℃.

[0084] Example 11

[0085] The bamboo activated carbon prepared in Example 4 was selected, and the content of Example 6 was modified as follows: the activation degradation temperature was 45 ℃.

[0086] The test results are shown in the table below.

[0087] Table 3 Test Results

[0088]

[0089] As shown in Table 3, increasing the activation and degradation temperature improves the degradation rate of the bamboo activated carbon prepared by this invention, but the improvement is not significant. At room temperature, the bamboo activated carbon of this invention has a significant degradation efficiency.

[0090] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics, characterized in that, Includes the following steps: (1) Bamboo is crushed, sieved and dried to obtain dried bamboo chips; (2) Mix the bamboo shavings obtained in step (1) with the activating agent to obtain a mixture; (3) The mixture obtained in step (2) above is subjected to ultrasonic impregnation treatment and then subjected to temperature-controlled and atmosphere-controlled pyrolysis to obtain pyrolytic carbon material; (4) The pyrolytic carbon material obtained in step (3) above is acid etched, and after etching, it is washed with water and dried to obtain bamboo activated carbon that has been activated to degrade aqueous antibiotics by persulfate.

2. The method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics according to claim 1, characterized in that, The activating agent used is a mixed activator solution with a concentration of 25~50 g / L, composed of ferric sulfate solution and copper sulfate solution, with a mass ratio of ferric sulfate to copper sulfate of 4:1~9:1; the immersion time is 60 min.

3. The method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics according to claim 1, characterized in that, The mass ratio of the activating reagent to the dried bamboo shavings raw material is 1:10 to 1:

20.

4. The method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics according to claim 1, characterized in that, The temperature-controlled and atmosphere-controlled pyrolysis process is as follows: the temperature is raised to 400~550 ℃ under a nitrogen atmosphere for 30~90 min, and then further raised to 750~850 ℃ under an ammonia-nitrogen mixed atmosphere for 30~60 min; the volume content of ammonia in the mixed atmosphere is 1%~10%.

5. The method for preparing bamboo activated carbon for activating persulfate degradation of aqueous antibiotics according to claim 1, characterized in that, The acid used for acid etching of the pyrolyzed carbon material is hydrochloric acid with a mass concentration of 1% to 10%.

6. Bamboo activated carbon prepared by any one of the methods described in claims 1-5.

7. The bamboo activated carbon according to claim 6, characterized in that, The specific surface area of ​​the activated carbon is 801~932 m². 2 / g, sulfur content is 1.27%~2.65%, nitrogen content is 0.78%~3.31%, Fe content is 1.89%~4.31%, and Cu content is 0.52%~1.26%.

8. The application of the bamboo activated carbon according to claim 6 in the activation of persulfate to degrade and remove antibiotics from wastewater, characterized in that, The specific method is as follows: Add the bamboo activated carbon and persulfate to the aqueous phase containing antibiotics, and stir to obtain a mixed solution; adjust the pH of the mixed solution to activate and degrade it.

9. The application according to claim 8, characterized in that, The antibiotic is tetracycline, and the persulfate is one or more of sodium persulfate, ammonium persulfate, or potassium persulfate.

10. The application according to claim 8, characterized in that, The antibiotic concentration is 20 mg / L, the solution volume is 100 mL, the amount of persulfate is 0.1~1.0 mM, the amount of bamboo activated carbon is 10~50 mg, the pH value is 3~10, and the activation and degradation are carried out at 25~50 ℃ for 2 h.

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