Water purification bamboo activated carbon and preparation method thereof

Abstract

The invention discloses water purification bamboo activated carbon and a preparation method thereof, and belongs to the technical field of activated carbon materials. According to the method, after bamboo wood is dried, the water purification bamboo activated carbon is prepared through one-step magnetization, nitrogen doping and activation. The moisture content of bamboo wood is regulated through drying pretreatment, the wettability of an activating agent in raw materials is promoted, and the activating effect is improved; through compounding of an activating agent and a nitrogen-doped modifier and oxygen-controlled gradient activation, activated carbon magnetization, surface modification and pore structure regulation are synchronously realized, the purification performance of activated carbon is improved, meanwhile, the consumption of an activating reagent is reduced, and the preparation process flow is simplified. The specific surface area of the bamboo activated carbon reaches 856.4 m < 2 > / g, the iodine adsorption value is 661.7 mg / g, and the adsorption capacities of residual chlorine, Ca < 2 + > and Mg < 2 + > in a multi-component adsorbate aqueous solution reach 594.5 mg / g, 164.9 mg / g and 126.2 mg / g.

Description

Technical Field

[0001] The invention belongs to the technical field of activated carbon materials, and particularly relates to water-purifying bamboo activated carbon and a preparation method thereof. Background Art

[0002] my country is rich in bamboo resources and is the world's leading bamboo producer. We lead the world in bamboo species resources, bamboo timber reserves and production, and bamboo product foreign trade. Bamboo's short growth cycle allows for sustainable recycling, making it a significant resource advantage. Bamboo processing generates significant amounts of waste. Developing technologies to utilize these wastes and improving their efficiency and benefits will help promote the comprehensive and efficient use of bamboo resources and the healthy development of the bamboo industry.

[0003] With the acceleration of industrialization and urbanization, environmental pollution is becoming increasingly prominent, impacting both production and daily life. Activated carbon, as a highly efficient adsorption material, has a wide range of applications in water purification, waste gas treatment, and heavy metal removal. The preparation of high-performance bamboo activated carbon using bamboo processing residues as raw material provides a path for the comprehensive and high-value utilization of bamboo resources.

[0004] Chemical activation is one of the main processes for preparing activated carbon, offering advantages such as simplicity, large-scale production, and high product performance. However, it is plagued by issues such as high activator consumption, high environmental pollution risks, and complex subsequent treatment processes. Improving the purification performance of activated carbon while reducing activator consumption is a development trend. Furthermore, the complex process for rapid separation and recovery of conventional activated carbon after adsorption limits its recycling efficiency. Magnetizing activated carbon, preparing magnetic activated carbon, and utilizing an external magnetic field to achieve rapid solid-liquid separation have effectively addressed the adsorption and separation issues of activated carbon. The preparation of high-performance magnetic activated carbon and the simplification of its preparation process are research hotspots, but currently, the main method for preparing high-performance magnetic activated carbon is a multi-step method involving magnetization and nitrogen-doping modification. This process is relatively complex, and the nitrogen-doping modification method in this multi-step method may only cover the surface of the activated carbon and even clog its pores, affecting its magnetic properties and active sites, resulting in poor purification performance and hindering its widespread application. Therefore, the development of low-consumption, easily separable, and high-performance activated carbon is of great significance. Summary of the Invention

[0005] One technical problem solved by the present invention is to provide a preparation method of water-purifying bamboo activated carbon. The bamboo material is dried and pre-treated to control the moisture content of the bamboo material, promote the penetration and infiltration of the activator into the raw material, and improve the activation effect. Ferric nitrate has both chemical activation and magnetic precursor functions, and simultaneously realizes pore construction and in-situ generation of magnetic nanoparticles at high temperature, which simplifies the process flow while significantly improving the adsorption performance and magnetic response characteristics of the activated carbon. By compounding the activator and the modifier and controlling oxygen step activation, a one-step magnetization-nitrogen doping-activation method is completed, and the magnetization, surface modification and pore structure control of the activated carbon are simultaneously achieved, which improves the purification performance of the activated carbon while reducing the consumption of activation reagents and simplifying the preparation process flow. Another technical problem to be solved by the present invention is to provide a water-purifying bamboo activated carbon, which has a specific surface area of ​​856.4m 2 / g, iodine adsorption value 661.7mg / g, for residual chlorine, Ca 2+ and Mg 2+ The adsorption amounts reached 594.5, 164.9 and 126.2 mg / g.

[0006] Technical solution: In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing water-purifying bamboo activated carbon comprises the following steps: pre-treating bamboo materials by drying and controlling, and then magnetizing, nitrogen-doping, and activating the bamboo materials in a one-step process to prepare low-consumption, high-performance water-purifying bamboo activated carbon, thereby reducing activator consumption and simplifying the preparation process.

[0008] According to the method, the bamboo material needs to be pre-treated for drying control, and the moisture content after drying is 5% to 15%; preferably, the moisture content after drying is 5% to 10%; more preferably, the moisture content after drying is 5%.

[0009] In the method, ferric nitrate is selected as an activator and a magnetizing agent, and the mass ratio of ferric nitrate to the dried bamboo is 1:100 to 1:5; preferably, the mass ratio of ferric nitrate to the dried bamboo is 1:100 to 15:100; further preferably, the mass ratio of ferric nitrate to the dried bamboo is 1:10.

[0010] In the method, the nitrogen-doped modifier used is a mixture of two or more of melamine, urea, and ethylenediamine, and the mass ratio of the nitrogen-doped modifier to the dried bamboo material is 1:10 to 1:20; preferably, the nitrogen-doped modifier used is a mixture of melamine and urea in a mass ratio of 1:2, or a mixture of melamine, urea, and ethylenediamine in a mass ratio of 1:1:1, or a mixture of melamine and urea in a mass ratio of 1:1, or a mixture of urea and ethylenediamine in a mass ratio of 1:1, or a mixture of melamine and ethylenediamine in a mass ratio of 1:1; the mass ratio of the nitrogen-doped modifier to the dried bamboo material is 1:10.

[0011] The method comprises an activation process of oxygen-controlled step activation, specifically: heating to 400-600° C. in an oxygen-free nitrogen atmosphere for activation for 30-60 min, then further heating to 700-900° C., and activating in an atmosphere with an oxygen content of 5%-15% for 30-60 min; preferably, heating to 400-600° C. at a rate of 10° C. / min in an oxygen-free nitrogen atmosphere for activation for 45-60 min, then further heating to 750-900° C. in an oxygen-free nitrogen atmosphere for activation for 30-60 min in an oxygen-controlled atmosphere with an oxygen content of 5%-15%; further preferably, heating to 500° C. at a rate of 10° C. / min in an oxygen-free nitrogen atmosphere for activation for 60 min, then further heating to 850° C. in an oxygen-free nitrogen atmosphere for activation for 30 min in an oxygen-controlled atmosphere with an oxygen content of 10%.

[0012] The method for preparing low-consumption, high-performance water-purifying bamboo activated carbon is characterized by comprising the following steps:

[0013] (1) The bamboo material is crushed and sieved to a particle size of 1 to 2 mm and then dried;

[0014] (2) The dried bamboo material is mixed with the ferric nitrate solution and the nitrogen-doped modifier, stirred and mixed at room temperature, and then immersed for 20 to 40 minutes; the concentration of the ferric nitrate solution is 10 to 200 g / L; preferably, the concentration of the ferric nitrate solution is 10 to 150 g / L, and the immersion time is 30 minutes; more preferably, the concentration of the ferric nitrate solution is 100 g / L;

[0015] (3) The mixture is placed in a tube furnace for oxygen-controlled step activation; after activation, the mixture is cooled to room temperature in an oxygen-free nitrogen atmosphere, and the sample is taken out, washed with water, and dried to obtain water-purifying bamboo activated carbon.

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

[0017] The above-mentioned water-purifying bamboo activated carbon is used to purify a multi-component adsorbent aqueous solution, and an aqueous solution containing 100 mg / L residual chlorine, 500 mg / L calcium ions and magnesium ions is adsorbed in the water. Bamboo activated carbon is added to the above solution, and 0.05-0.15 g of bamboo activated carbon is added to every 500 mL of the above-mentioned aqueous solution; the adsorption time is 3-5 hours; preferably, 500 mL of the above-mentioned solution is added with a 0.1 g sample of bamboo activated carbon, and the adsorption time is 4 hours.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0019] (1) The present invention controls the moisture content of the raw materials, improves the permeability of the activator, and enhances the activation effect; selects ferric nitrate as the activator to achieve the dual effects of activation and magnetization; and completes magnetization, nitrogen doping and activation in one step by compounding the activator and the modifier and performing oxygen-controlled step activation, thereby simultaneously achieving magnetization of activated carbon, surface modification and pore structure regulation, improving the purification performance of activated carbon and giving it good separation characteristics, while reducing the consumption of activator in the preparation process and simplifying the preparation process.

[0020] (2) The specific surface area of ​​bamboo activated carbon of the present invention is 856.4m 2 / g, iodine adsorption value 661.7mg / g, for residual chlorine, Ca 2+ and Mg 2+ The adsorption amounts reached 594.5, 164.9 and 126.2 mg / g. DETAILED DESCRIPTION

[0021] The present invention will be further illustrated below with reference to specific examples. The examples are implemented based on the technical solutions of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0022] Example 1

[0023] The method for preparing low-consumption, high-performance water-purifying bamboo activated carbon comprises the following steps:

[0024] (1) The bamboo material is crushed and sieved to a particle size of 1-2 mm, and then dried to control the moisture content to 5%;

[0025] (2) Take 100g of dried bamboo, add 100ml of 50g / L ferric nitrate solution, then add nitrogen-doping modifier according to the bamboo and nitrogen-doping modifier mass ratio of 15:1, the nitrogen-doping modifier is composed of melamine and urea according to the mass ratio of 1:1, stir and mix evenly at room temperature and soak for 30min;

[0026] (3) The mixed impregnated material was placed in a tube furnace, heated to 450°C at a rate of 10°C / min in an oxygen-free nitrogen atmosphere for activation for 60 min, then further heated to 800°C in an oxygen-free nitrogen atmosphere, and activated for 30 min in an oxygen-controlled atmosphere with an oxygen content of 10%;

[0027] (4) After activation, the temperature was lowered to room temperature in an oxygen-free nitrogen atmosphere, and the sample was taken out and washed with water and dried to obtain water-purifying bamboo activated carbon.

[0028] Example 2

[0029] The method for preparing low-consumption, high-performance water-purifying bamboo activated carbon comprises the following steps:

[0030] (1) The bamboo material is crushed and sieved to a particle size of 1-2 mm, and then dried to control the moisture content to 10%;

[0031] (2) Take 100g of dried bamboo, add 100ml of 100g / L ferric nitrate solution, then add nitrogen-doping modifier according to the bamboo and nitrogen-doping modifier mass ratio of 10:1, the nitrogen-doping modifier is composed of melamine and urea according to the mass ratio of 1:2, stir and mix evenly at room temperature and soak for 30min;

[0032] (3) The mixed impregnated material was placed in a tube furnace, heated to 500°C at a rate of 10°C / min in an oxygen-free nitrogen atmosphere for activation for 60 min, then further heated to 850°C in an oxygen-free nitrogen atmosphere, and activated for 30 min in an oxygen-controlled atmosphere with an oxygen content of 10%;

[0033] (4) After activation, the temperature was lowered to room temperature in an oxygen-free nitrogen atmosphere, and the sample was taken out and washed with water and dried to obtain water-purifying bamboo activated carbon.

[0034] Example 3

[0035] The method for preparing low-consumption, high-performance water-purifying bamboo activated carbon comprises the following steps:

[0036] (1) The bamboo material is crushed and sieved to a particle size of 1-2 mm, and then dried to control the moisture content to 5%;

[0037] (2) Take 100g of dried bamboo, add 100ml of 10g / L ferric nitrate solution, then add nitrogen-doping modifier according to the mass ratio of bamboo to nitrogen-doping modifier of 12:1, the nitrogen-doping modifier is composed of melamine, urea and ethylenediamine according to the mass ratio of 1:1:1, stir and mix evenly at room temperature and soak for 30min;

[0038] (3) The mixed impregnated material was placed in a tube furnace, heated to 400°C at a rate of 10°C / min in an oxygen-free nitrogen atmosphere for activation for 60 min, then further heated to 750°C in an oxygen-free nitrogen atmosphere, and activated in an oxygen-controlled atmosphere with an oxygen content of 15% for 45 min;

[0039] (4) After activation, the temperature was lowered to room temperature in an oxygen-free nitrogen atmosphere, and the sample was taken out and washed with water and dried to obtain water-purifying bamboo activated carbon.

[0040] Example 4

[0041] The method for preparing low-consumption, high-performance water-purifying bamboo activated carbon comprises the following steps:

[0042] (1) The bamboo material is crushed and sieved to a particle size of 1-2 mm, and then dried to control the moisture content to 15%;

[0043] (2) Take 100g of dried bamboo, add 100ml of 50g / L ferric nitrate solution, then add nitrogen-doping modifier according to the bamboo and nitrogen-doping modifier mass ratio of 20:1, the nitrogen-doping modifier is composed of melamine and ethylenediamine according to the mass ratio of 1:1, stir and mix evenly at room temperature and soak for 30min;

[0044] (3) The mixed impregnated material was placed in a tube furnace, heated to 400°C at a rate of 10°C / min in an oxygen-free nitrogen atmosphere for activation for 60 min, then further heated to 900°C in an oxygen-free nitrogen atmosphere, and activated in an oxygen-controlled atmosphere with an oxygen content of 12% for 45 min;

[0045] (4) After activation, the temperature was lowered to room temperature in an oxygen-free nitrogen atmosphere, and the sample was taken out and washed with water and dried to obtain water-purifying bamboo activated carbon.

[0046] Example 5

[0047] The method for preparing low-consumption, high-performance water-purifying bamboo activated carbon comprises the following steps:

[0048] (1) The bamboo material is crushed and sieved to a particle size of 1-2 mm, and then dried to control the moisture content to 10%;

[0049] (2) Take 100g of dried bamboo, add 100ml of 100g / L ferric nitrate solution, then add nitrogen-doping modifier according to the bamboo and nitrogen-doping modifier mass ratio of 12:1, the nitrogen-doping modifier is composed of melamine and urea according to the mass ratio of 1:1, stir and mix evenly at room temperature and soak for 30min;

[0050] (3) The mixed impregnated material was placed in a tube furnace, heated to 450°C at a rate of 10°C / min in an oxygen-free nitrogen atmosphere, and activated for 45 min. Thereafter, the temperature was further raised to 850°C in an oxygen-free nitrogen atmosphere, and activated for 45 min in an oxygen-controlled atmosphere with an oxygen content of 5%;

[0051] (4) After activation, the temperature was lowered to room temperature in an oxygen-free nitrogen atmosphere, and the sample was taken out and washed with water and dried to obtain water-purifying bamboo activated carbon.

[0052] Example 6

[0053] The method for preparing low-consumption, high-performance water-purifying bamboo activated carbon comprises the following steps:

[0054] (1) The bamboo material is crushed and sieved to a particle size of 1-2 mm, and then dried to control the moisture content to 8%;

[0055] (2) Take 100g of dried bamboo, add 100ml of 150g / L ferric nitrate solution, then add nitrogen-doping modifier according to the bamboo and nitrogen-doping modifier mass ratio of 15:1, the nitrogen-doping modifier is composed of melamine and urea according to the mass ratio of 1:1, stir and mix evenly at room temperature and soak for 30min;

[0056] (3) The mixed impregnated material was placed in a tube furnace, heated at 10°C / min to 600°C in an oxygen-free nitrogen atmosphere for activation for 60 min, then further heated to 800°C in an oxygen-free nitrogen atmosphere, and activated in an oxygen-controlled atmosphere with an oxygen content of 8% for 45 min;

[0057] (4) After activation, the temperature was lowered to room temperature in an oxygen-free nitrogen atmosphere, and the sample was taken out and washed with water and dried to obtain water-purifying bamboo activated carbon.

[0058] Example 7

[0059] The method for preparing low-consumption, high-performance water-purifying bamboo activated carbon comprises the following steps:

[0060] (1) The bamboo material is crushed and sieved to a particle size of 1-2 mm, and then dried to control the moisture content to 5%;

[0061] (2) Take 100g of dried bamboo, add 100ml of 100g / L ferric nitrate solution, then add nitrogen-doping modifier according to the bamboo and nitrogen-doping modifier mass ratio of 20:1, the nitrogen-doping modifier is composed of urea and ethylenediamine according to the mass ratio of 1:1, stir and mix evenly at room temperature and soak for 30min;

[0062] (3) The mixed impregnated material was placed in a tube furnace, heated at 10°C / min to 600°C in an oxygen-free nitrogen atmosphere for activation for 60 min, then further heated to 900°C in an oxygen-free nitrogen atmosphere, and activated in an oxygen-controlled atmosphere with an oxygen content of 15% for 60 min;

[0063] (4) After activation, the temperature was lowered to room temperature in an oxygen-free nitrogen atmosphere, and the sample was taken out and washed with water and dried to obtain water-purifying bamboo activated carbon.

[0064] Comparative Example 1

[0065] A preparation method of bamboo activated carbon comprises the following steps:

[0066] (1) The bamboo material is crushed and sieved to a particle size of 1-2 mm, and then dried to control the moisture content to 10%;

[0067] (2) Add 200 g of 50% phosphoric acid solution to 100 g of dried bamboo, stir evenly and soak for 30 min at room temperature;

[0068] (3) The mixed impregnated material was placed in a tube furnace, heated at 10°C / min to 400°C in an oxygen-free nitrogen atmosphere for activation for 30 min, then further heated to 700°C in an oxygen-free nitrogen atmosphere, and activated in an oxygen-controlled atmosphere with an oxygen content of 5% for 30 min;

[0069] (4) After activation, the temperature was lowered to room temperature in an oxygen-free nitrogen atmosphere, and the sample was taken out and washed with water and dried to obtain bamboo activated carbon.

[0070] Comparative Example 2

[0071] A preparation method of bamboo activated carbon comprises the following steps:

[0072] (1) The bamboo material is crushed and sieved to a particle size of 1-2 mm, and then dried to control the moisture content to 10%;

[0073] (2) Add 400 g of 50% phosphoric acid solution to 100 g of dried bamboo, stir evenly and soak for 60 min at room temperature;

[0074] (3) The mixed impregnated material was placed in a tube furnace and heated to 450°C at a rate of 10°C / min under an oxygen-free nitrogen atmosphere for activation for 60 min;

[0075] (4) After activation, the temperature was lowered to room temperature in an oxygen-free nitrogen atmosphere, and the sample was taken out and washed with water and dried to obtain bamboo activated carbon.

[0076] The specific surface area of ​​the samples was tested using a nitrogen adsorption-desorption instrument in accordance with the national standard GB / T 19587-2017.

[0077] Prepare an aqueous solution containing 100 mg / L residual chlorine, 500 mg / L calcium ions and magnesium ions. Take 500 mL of the above solution and add 0.1 g of bamboo activated carbon sample. The adsorption time is 4 hours. Test the concentrations of residual chlorine, calcium ions and magnesium ions before and after adsorption, and calculate the adsorption amount.

[0078] The concentrations of calcium and magnesium ions were tested by inductively coupled plasma emission spectrometry (ICP) according to the national standard GB / T17476.

[0079] The residual chlorine concentration is tested using a residual chlorine detector in accordance with the national metrology technical specification JJF 1609-2017.

[0080] The above test results are shown in Table 1 below.

[0081] Table 1 Performance test results of water purification bamboo activated carbon prepared in Examples 1-7 and Comparative Examples 1-2

[0082]

[0083] From the results in Table 1, it can be seen that the bamboo activated carbon prepared in Examples 1-7 of the present invention has outstanding purification performance, and can effectively remove residual chlorine, Ca 2+ and Mg 2+ The adsorption capacity can reach 594.5, 164.9 and 126.2 mg / g.

[0084] Combining Example 2 and Comparative Examples 1-2, it can be seen that the present invention prepares high-performance water-purifying bamboo activated carbon by drying controlled pretreatment of bamboo materials and magnetization-nitrogen doping-activation in one step, thereby reducing activator consumption and simplifying the preparation process.

[0085] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing water-purifying bamboo activated carbon, characterized in that: After drying and pretreatment, bamboo activated carbon for water purification was prepared by a one-step method of magnetization-nitrogen doping-activation.

2. The method for preparing water-purifying bamboo activated carbon according to claim 1, wherein: The moisture content of bamboo after drying is 5% to 15%.

3. The method for preparing water-purifying bamboo activated carbon according to claim 1, characterized in that: Ferric nitrate is used as an activating agent and a magnetic agent, and the mass ratio of ferric nitrate to the dried bamboo material is 1:100 to 1:

5.

4. The method for preparing water-purifying bamboo activated carbon according to claim 1, wherein: The nitrogen-doped modifier is a mixture of two or more of melamine, urea and ethylenediamine, and the mass ratio of the nitrogen-doped modifier to the dried bamboo material is 1:10 to 1:

20.

5. The method for preparing water-purifying bamboo activated carbon according to claim 1, wherein: The activation process is oxygen-controlled step activation, specifically: heating to 400-600°C in an oxygen-free nitrogen atmosphere for activation for 30-60 minutes, then further heating to 700-900°C and activating in an atmosphere with an oxygen content of 5%-15% for 30-60 minutes.

6. The method for preparing water-purifying bamboo activated carbon according to claim 1, wherein: The following steps are involved: (1) The bamboo material is crushed and sieved to a particle size of 1 to 2 mm and then dried; (2) The dried bamboo material is mixed evenly with the ferric nitrate solution and the nitrogen-doped modifier, stirred and mixed evenly at room temperature, and then immersed for 20 to 40 minutes; the concentration of the ferric nitrate solution is 10 to 200 g / L; (3) The mixture is placed in a tube furnace for oxygen-controlled step activation. After activation, the mixture is cooled to room temperature in an oxygen-free nitrogen atmosphere. The sample is taken out and washed with water and dried to obtain water-purifying bamboo activated carbon.

7. Water-purifying bamboo activated carbon prepared by the method according to any one of claims 1 to 6.

8. The application according to claim 7, characterized in that: The method comprises the following steps: adsorbing an aqueous solution containing 100 mg / L residual chlorine, 500 mg / L calcium ions and magnesium ions, adding bamboo activated carbon to the aqueous solution, and adding 0.05 to 0.15 g of bamboo activated carbon to every 500 mL of the aqueous solution; and adsorbing for 3 to 5 hours.

9. The application according to claim 8, characterized in that: 0.1 g of bamboo activated carbon was added to 500 mL of the aqueous solution, and the adsorption time was 4 h.

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