Method for preparing biomass activated carbon by activating bamboo shaving with bamboo vinegar

Abstract

The present application belongs to the technical field of biomass activated carbon preparation, and particularly relates to a method for preparing activated carbon from bamboo vinegar activated bamboo shaving and application. The method uses bamboo vinegar as a single chemical activator to have hydrolysis, dehydration and cross-linking reaction with bamboo shaving, and the preparation process uses bamboo vinegar and bamboo shaving, two by-products generated by bamboo processing enterprises, as raw materials to prepare biomass carbon, thereby constructing an activated carbon preparation process based on biomass resources. The method not only makes up for the high production cost and environmental pollution caused by the current phosphoric acid activation method, and finds a green and environmentally-friendly preparation method for activated carbon chemical activation technology, but also provides a new technical approach for resource utilization of bamboo vinegar and bamboo shaving. The specific surface area of the obtained activated carbon can reach 816 m 2 / g, the adsorption capacity of methylene blue in water reaches 123.6 mg / g, and the yield is 37.2%, which can be applied in the field of environmental engineering for adsorbing and removing pollutants.

Description

Technical Field

[0001] This invention belongs to the field of biomass activated carbon preparation technology, specifically relating to a method for preparing biomass charcoal by activating bamboo shavings with bamboo vinegar and its application. Background Technology

[0002] Biomass activated carbon refers to environmental functional materials that utilize various biological resources such as fruit shells / kernels, wood and bamboo, straw, and organic solid waste as carbon-containing raw materials. After carbonization and activation treatment, they possess a large specific surface area and abundant surface chemical active groups, making them suitable for adsorbing specific pollutants. China is the kingdom of bamboo, and Yibin is one of the top ten bamboo resource-rich areas in the country. Its bamboo resources are abundant, and the local bamboo processing industry is well-developed. The process of using bamboo to make furniture and household goods generates a large amount of solid waste such as bamboo shavings and bamboo chips. The production of bamboo charcoal using pyrolysis produces a large amount of byproducts such as bamboo vinegar. Therefore, comprehensively utilizing these organic wastes can help enterprises maintain normal production while avoiding resource waste. Bamboo shavings and bamboo chips are excellent raw materials for preparing activated carbon, which is widely used in the adsorption and removal of pollutants from water. Phosphoric acid activation is currently a major technology for preparing activated carbon. This method uses phosphoric acid as an activating agent, producing activated carbon with a large specific surface area and high yield, but the production cost is high and it easily causes environmental pollution, making it difficult to fully achieve carbon reduction and carbon neutrality in the biomass utilization process. Bamboo vinegar is a major byproduct of the pyrolysis of bamboo and other biomass. It is produced in large quantities; approximately one-quarter of the products from one ton of biomass pyrolysis is bamboo vinegar. Expanding the application of bamboo vinegar in various industries has become crucial for current biomass pyrolysis processes. Bamboo vinegar contains a large amount of natural organic acids, primarily acetic acid, a monoprotic protic acid with a pH value typically reaching 2-3. It can completely replace phosphoric acid as an acidic activator in the preparation of activated carbon. The activation principle of organic matter by bamboo vinegar mainly includes hydrolysis, dehydration, and cross-linking. 1. Hydrolysis Plant fibers are mainly composed of high molecular weight complexes (cell walls) made of polysaccharides (a general term for hemicellulose and cellulose) and lignin. The organic acids (mainly acetic acid) in bamboo vinegar continuously catalyze the hydrolysis of polysaccharides through the protonation of hydrogen ions, transforming them into low molecular weight substances such as oligosaccharides or monosaccharides. These low molecular weight substances are fluid and can fill the gaps in plant cell cavities, facilitating the formation of pores during subsequent heat treatment and carbonization. At the same time, these low molecular weight hydrolysis products are easier to carbonize during heat treatment. In addition, as plant fibers continue to hydrolyze, organic acids gradually penetrate into the interior of plant cell walls, swelling the plant fibers and facilitating the formation of pore structures during subsequent heat treatment.

[0003] 2. Catalytic dehydration The polysaccharides in plant fibers contain abundant hydroxyl groups, which can be removed through dehydration during pyrolysis. Acetic acid, a protic acid, can catalyze the dehydration reaction during the high-temperature carbonization of polysaccharides and their hydrolysis products, thereby reducing the hydrogen and oxygen content in the carbonized products and increasing the carbonization yield.

[0004] 3. Cross-linking effect Acetic acid can crosslink with polysaccharides and their hydrolysis products through esterification, preventing the shrinkage of plant cell walls during heat treatment and laying an important foundation for the formation of the porous structure of activated carbon. Summary of the Invention

[0006] To address the problems in the background technology, this invention proposes using bamboo vinegar and bamboo shavings, generated during the production process of bamboo processing enterprises in Yibin City, as raw materials. Bamboo vinegar is used as an activator to activate the bamboo shavings, and both byproducts are used as raw materials to prepare activated carbon. This couples the biomass pyrolysis process with the activated carbon preparation process, constructing a green and environmentally friendly activated carbon preparation technology entirely based on biomass resources. This not only promotes the comprehensive utilization of Yibin bamboo shavings and bamboo vinegar resources but also provides a new activator and activation method for activated carbon chemical activation technology. To determine the optimal process conditions for preparing activated carbon from bamboo shavings using bamboo acetic acid activation, this invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing activated carbon, comprising the following steps: (1) Pretreatment: Bamboo shavings were washed with distilled water and dried to obtain material 1; (2) Grinding and sieving: Grind material 1 using a ball mill to obtain material 2; (3) Pre-activation: Mix material 2 with bamboo vinegar at a predetermined mass ratio at room temperature and then activate at a predetermined temperature for a predetermined time for a predetermined time to obtain material 3; (4) Microwave high-temperature carbonization: Under nitrogen protection (nitrogen rate 0.1 L / min), material 3 is placed in a microwave tube furnace and carbonized at a predetermined temperature 2 for a predetermined time 2 at a predetermined heating rate. After cooling to room temperature, it is taken out to obtain material 4. (5) Washing and drying: Wash material 4 with distilled water until neutral, and then dry it to obtain material 5; (6) Grinding and sieving: Grind material 5 and then sieve it to obtain activated carbon of bamboo vinegar activated bamboo peel peanut material, i.e. material 6.

[0007] Optionally, the raw materials include bamboo vinegar and bamboo shavings, with the bamboo vinegar acting as an activator. In a second aspect, the present invention provides activated carbon prepared by the aforementioned activated carbon preparation method, wherein the yield of the activated carbon is 37.2% and the specific surface area reaches 816 m².2 The adsorption capacity for methylene blue reaches 123.6 mg / g. The preparation method of this invention has a short process flow and is simple to operate.

[0008] In a third aspect, the activated carbon is used in the field of environmental engineering to adsorb and remove pollutants in the field of environmental engineering.

[0009] Beneficial effects: This invention uses bamboo vinegar and bamboo shavings produced during the production process of local bamboo processing enterprises in Yibin City as raw materials. Bamboo vinegar is used as an activator to activate bamboo shavings. The two byproducts, bamboo vinegar and bamboo shavings, are used as raw materials to prepare activated carbon. By coupling the biomass pyrolysis process with the activated carbon preparation process, a green and environmentally friendly activated carbon preparation technology based entirely on biomass resources is constructed. This technology not only promotes the comprehensive utilization of bamboo shavings and bamboo vinegar in Yibin, but also provides a new activator and activation method for activated carbon chemical activation technology. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0011] In one embodiment of the present invention, a method for preparing activated carbon is provided, wherein the membrane material comprises a substrate material filter membrane, comprising the following steps: (1) Pretreatment: Bamboo shavings were washed with distilled water and dried to obtain material 1; (2) Grinding and sieving: Grind material 1 using a ball mill to obtain material 2; (3) Pre-activation: Mix material 2 with bamboo vinegar at a predetermined mass ratio at room temperature and then activate at a predetermined temperature for a predetermined time for a predetermined time to obtain material 3; (4) Microwave high-temperature carbonization: Under nitrogen protection (nitrogen rate 0.1 L / min), material 3 is placed in a microwave tube furnace and carbonized at a predetermined temperature 2 for a predetermined time 2 at a predetermined heating rate. After cooling to room temperature, it is taken out to obtain material 4. (5) Washing and drying: Wash material 4 with distilled water until neutral, and then dry it to obtain material 5; (6) Grinding and sieving: Grind material 5 and then sieve it to obtain activated carbon of bamboo vinegar activated bamboo peel peanut material, i.e. material 6.

[0012] Information on some reagents and equipment used in specific embodiments of the present invention: 1. Bamboo shavings were sourced from local bamboo processing enterprises in Yibin; bamboo vinegar was sourced from local bamboo pyrolysis charcoal production enterprises in Yibin; methylene blue was an analytical grade reagent (AR grade) produced by Tianjin Kemeio Chemical Reagent Co., Ltd. 2. The main facilities for activated carbon preparation are as follows: Grinding: QM-3SP2 planetary ball mill (Nanjing Chishun Technology Development Co., Ltd.).

[0013] Drying: 101-2AB type electric heating forced air drying oven (Beijing Zhongxing Weiye Century Instrument Co., Ltd.).

[0014] Weighing: BSA124S-CW electronic balance (Sartorius Scientific Instruments Co., Ltd.).

[0015] Microwave carbonization: MKG-M2HB type microwave tube oven (Qingdao Maikewei Microwave Innovation Technology Co., Ltd.)

[0016] 3. The instruments used for characterizing activated carbon and testing its adsorption performance are as follows: Specific surface area: 3H-2000BET-A type specific surface area measuring instrument (Best Instruments Technology Co., Ltd.).

[0017] Surface functional groups: IRAFFINITY-1S Fourier transform infrared spectrometer (FTIR) (Shimadzu Corporation, Japan).

[0018] Methylene blue: colorimetric method, UV1901PC UV-Vis spectrophotometer (Shanghai Aoxi Scientific Instruments Co., Ltd.).

[0019] Activated carbon yield: weighing method.

[0020] To better understand the technical solution provided by the present invention, the following describes a method for preparing biomass activated carbon by activating bamboo shavings with bamboo vinegar using the above-described embodiments of the present invention, as well as performance testing, using several specific examples.

[0021] Example 1, Preparation of activated carbon: 1) Preparation of bamboo shaving powder: After washing the bamboo shavings with distilled water, dry them at 105℃ for 2 hours, then pass them through a 20-mesh sieve and put them into a desiccator for later use. 2) Pre-activation: Mix bamboo shavings powder and bamboo vinegar in a mass ratio of 1:2 and impregnate for 60 minutes. Then, pre-activate at 150°C for 60 minutes.

[0022] 3) Microwave carbonization: Place the pre-activated mixture into a microwave tube furnace, under nitrogen protection (nitrogen rate 0.1 L / min), carbonize at 400℃ for 60 minutes at a heating rate of 18℃ / min, and remove after cooling to room temperature.

[0023] 4) Washing and drying: Wash the carbonized material with distilled water until neutral, and then dry it at 120°C for 2 hours.

[0024] 5) Grinding and sieving: Grind the dried material above through a 40-mesh sieve to obtain biomass activated carbon prepared by activating bamboo shavings with bamboo vinegar.

[0025] Example 2, Preparation of activated carbon; 1) Preparation of bamboo shaving powder: After washing the bamboo shavings with distilled water, dry them at 105℃ for 2 hours, then pass them through a 20-mesh sieve and put them into a desiccator for later use. 2) Pre-activation: Mix bamboo shavings powder and bamboo vinegar in a mass ratio of 1:4 and impregnate for 60 minutes. Then, pre-activate at 150°C for 60 minutes.

[0026] 3) Microwave carbonization: Place the pre-activated mixture into a microwave tube furnace, under nitrogen protection (nitrogen rate 0.1 L / min), carbonize at 400℃ for 60 minutes at a heating rate of 18℃ / min, and remove after cooling to room temperature.

[0027] 4) Washing and drying: Wash the carbonized material with distilled water until neutral, and then dry it at 120°C for 2 hours.

[0028] 5) Grinding and sieving: Grind the dried material above through a 40-mesh sieve to obtain biomass activated carbon prepared by activating bamboo shavings with bamboo vinegar.

[0029] Example 3, Preparation of activated carbon; 1) Preparation of bamboo shaving powder: After washing the bamboo shavings with distilled water, dry them at 105℃ for 2 hours, then pass them through a 20-mesh sieve and put them into a desiccator for later use. 2) Pre-activation: Mix bamboo shavings powder and bamboo vinegar in a mass ratio of 1:6 and impregnate for 60 minutes. Then pre-activate at 150°C for 60 minutes.

[0030] 3) Microwave carbonization: Place the pre-activated mixture into a microwave tube furnace, under nitrogen protection (nitrogen rate 0.1 L / min), carbonize at 400℃ for 60 minutes at a heating rate of 18℃ / min, and remove after cooling to room temperature.

[0031] 4) Washing and drying: Wash the carbonized material with distilled water until neutral, and then dry it at 120°C for 2 hours.

[0032] 5) Grinding and sieving: Grind the dried material above through a 40-mesh sieve to obtain biomass activated carbon prepared by activating bamboo shavings with bamboo vinegar.

[0033] Example 4, Preparation of activated carbon; 1) Preparation of bamboo shaving powder: After washing the bamboo shavings with distilled water, dry them at 105℃ for 2 hours, then pass them through a 20-mesh sieve and put them into a desiccator for later use. 2) Pre-activation: Mix bamboo shavings powder and bamboo vinegar in a mass ratio of 1:2 and impregnate for 60 minutes. Then, pre-activate at 150°C for 60 minutes.

[0034] 3) Microwave carbonization: Place the pre-activated mixture into a microwave tube furnace, under nitrogen protection (nitrogen rate 0.1 L / min), carbonize at 500℃ for 90 minutes at a heating rate of 18℃ / min, and remove after cooling to room temperature.

[0035] 4) Washing and drying: Wash the carbonized material with distilled water until neutral, and then dry it at 120°C for 2 hours.

[0036] 5) Grinding and sieving: Grind the dried material above through a 40-mesh sieve to obtain biomass activated carbon prepared by activating bamboo shavings with bamboo vinegar.

[0037] Example 5, Preparation of activated carbon; 1) Preparation of bamboo shaving powder: After washing the bamboo shavings with distilled water, dry them at 105℃ for 2 hours, then pass them through a 20-mesh sieve and put them into a desiccator for later use. 2) Pre-activation: Mix bamboo shavings powder and bamboo vinegar in a mass ratio of 1:4 and impregnate for 60 minutes. Then, pre-activate at 150°C for 60 minutes.

[0038] 3) Microwave carbonization: Place the pre-activated mixture into a microwave tube furnace, under nitrogen protection (nitrogen rate 0.1 L / min), carbonize at 500℃ for 90 minutes at a heating rate of 18℃ / min, and remove after cooling to room temperature.

[0039] 4) Washing and drying: Wash the carbonized material with distilled water until neutral, and then dry it at 120°C for 2 hours.

[0040] 5) Grinding and sieving: Grind the dried material above through a 40-mesh sieve to obtain biomass activated carbon prepared by activating bamboo shavings with bamboo vinegar.

[0041] Example 6, Preparation of activated carbon; 1) Preparation of bamboo shaving powder: After washing the bamboo shavings with distilled water, dry them at 105℃ for 2 hours, then pass them through a 20-mesh sieve and put them into a desiccator for later use. 2) Pre-activation: Mix bamboo shavings powder and bamboo vinegar in a mass ratio of 1:6 and impregnate for 60 minutes. Then pre-activate at 150°C for 60 minutes.

[0042] 3) Microwave carbonization: Place the pre-activated mixture into a microwave tube furnace, under nitrogen protection (nitrogen rate 0.1 L / min), carbonize at 500℃ for 90 minutes at a heating rate of 18℃ / min, and remove after cooling to room temperature.

[0043] 4) Washing and drying: Wash the carbonized material with distilled water until neutral, and then dry it at 120°C for 2 hours.

[0044] 5) Grinding and sieving: Grind the dried material above through a 40-mesh sieve to obtain biomass activated carbon prepared by activating bamboo shavings with bamboo vinegar.

[0045] Experiment 7: Material characterization and methylene blue adsorption performance test; The activated carbon prepared under different conditions in Examples 1-6 was characterized and used to adsorb methylene blue in water. The test results are shown in Table 1. Table 1. Characterization and methylene blue adsorption performance test of activated carbon prepared under different conditions ; Based on the results in Table 1, the optimized preparation conditions for activated carbon are as follows: After washing bamboo shavings with distilled water, they were dried at 105℃ for 2 hours and then passed through a 20-mesh sieve. The bamboo shaving powder was mixed with bamboo vinegar at a mass ratio of 1:6 and impregnated for 60 minutes, and then pre-activated at 150℃ for 60 minutes. After that, it was placed in a microwave tube furnace and carbonized at 400℃ for 60 minutes under nitrogen protection (nitrogen rate 0.1 L / min) with a heating rate of 18℃ / min. After cooling to room temperature, it was washed with distilled water until neutral, and then dried at 120℃ for 2 hours. Finally, it was ground and passed through a 40-mesh sieve to obtain biomass activated carbon prepared from bamboo shavings activated with bamboo vinegar.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing biomass activated carbon by activating bamboo shavings with bamboo vinegar, characterized in that, The preparation process includes the following six steps: S1. Pretreatment: Bamboo shavings are washed with distilled water and dried to obtain material 1; S2. Grinding and sieving: Grind material 1 using a ball mill to obtain material 2; S3. Pre-activation: Mix material 2 with bamboo vinegar at a predetermined mass ratio and impregnate at room temperature, then activate at a predetermined temperature 1 for a predetermined time 1 to obtain material 3; S4. Microwave high-temperature carbonization: Under nitrogen protection, material 3 is placed in a microwave tube furnace and carbonized at a predetermined temperature 2 for a predetermined time 2 at a predetermined heating rate. After cooling to room temperature, it is taken out to obtain material 4. S5. Washing and drying: Wash material 4 with distilled water until neutral, then dry to obtain material 5; S6. Grinding and sieving: Grind material 5 and then sieve it to obtain activated carbon from bamboo vinegar activated bamboo shavings and peanut materials, i.e., material 6.

2. The method as described in claim 1, characterized in that, The raw materials for preparation include bamboo vinegar and bamboo shavings, with bamboo vinegar serving as an activator.

3. The method as described in claim 1, characterized in that, The drying temperature and drying time in step S1 are 105℃ and 2 hours, respectively.

4. The method as described in claim 1, characterized in that, After grinding in step S2, the material is passed through a 20-mesh sieve.

5. The method as described in claim 1, characterized in that, In step S3, the mass ratio of bamboo shavings powder to bamboo vinegar for impregnation is 1:2~6, the impregnation time is 60 minutes, the pre-activation predetermined temperature 1 is 150℃, and the predetermined time 1 is 60 minutes.

6. The method as described in claim 1, characterized in that, In step S4, the heating rate of the microwave tube furnace is 18°C / minute, the microwave carbonization predetermined temperature 2 is 400~500°C, and the carbonization predetermined time 2 is 60~90 minutes.

7. The method as described in claim 1, characterized in that, In step S5, the drying temperature is 120℃ and the drying time is 2 hours.

8. The method as described in claim 1, characterized in that, In step S6, the sample is sieved through a 40-mesh sieve.

9. Activated carbon obtained by the method for preparing biomass activated carbon according to any one of claims 1-8.

10. An application of the activated carbon as described in claim 9 in the field of environmental engineering.