CN104925807A - Method for manufacturing activated carbon from caragana microphylla - Google Patents

Abstract

The invention relates to a method for preparing activated carbon using caragana as raw material. The method is to cut caragana into sections and preliminarily carbonize in a microwave cracking reaction furnace; Caragana coke is soaked in phosphoric acid solution for 3-20 hours, after drying, it is activated in a muffle furnace at a constant temperature; after cooling, it is washed with alkali and water until neutral, and dried to obtain a kind of wood activated carbon. The activated carbon prepared by the present invention has good adsorption performance and well-developed pores. The optimal ash content and iodine adsorption value of caragana activated carbon are 2.77%, 1213.37mg.g ^-1 (>1000mg.g ^-1 ), and the main indicators are all up to woody National first-class product index requirements for activated carbon for water purification. Using abundant reserves of forestry waste caragana as raw material and microwave as pretreatment technology to prepare activated carbon can save energy and time to produce activated carbon with well-developed pores and excellent adsorption performance, realizing the resource utilization of agricultural and forestry waste.

Description

A kind of activated carbon preparation method taking caragana as raw material

technical field

The invention relates to a method for preparing activated carbon using caragana as raw material, specifically a method for preparing high-quality wood activated carbon by using caragana as raw material, microwave carbonization pretreatment and chemical activation, which belongs to the development and utilization of biomass energy and activated carbon Preparation technology field.

Background technique

In recent years, with the rapid development of industry and the continuous strengthening of environmental awareness at all levels of society, activated carbon has been widely used in environmental protection, food, agriculture, catalyst applications, electrode materials, medicine and other fields. While the market demand for activated carbon products is increasing day by day, the cost factor limits the application of activated carbon. Therefore, it is an effective way to save costs and promote the production and application of activated carbon to seek raw materials with low price and large reserves and improve the preparation process of activated carbon.

Caragana is a deciduous shrub belonging to the leguminous family Caragana. It is an important tree species for windbreak, sand fixation, and water and soil conservation in the "Three North" regions of my country. The planting area of caragana is extensive, and regular stubble is required, and the yield per mu is about 300-500 kg. After stubble, the caragana regenerates quickly and can produce huge biomass. However, in northern China, a large amount of caragana after stubble is discarded in the sand or used as simple firewood, and its energy and economic value has not been fully utilized. At present, the preparation methods of activated carbon mainly include physical activation method and chemical activation method. The chemical activation method conducts a series of chemical reactions inside the carbon body under high temperature through the activator to generate a well-developed pore structure and surface functional groups, thereby forming activated carbon with high specific surface area and adsorption performance. This method is simple to operate and has low production cost, and is the main method for industrially producing activated carbon.

Microwave heating is accomplished through the interaction between particles inside the material and high-speed alternating electromagnetic waves, which overcomes the shortcomings of traditional heat transfer heating methods such as long time-consuming, uneven heating, and high requirements on the size of raw materials. The coke obtained by microwave carbonization pretreatment has more pores and more uniform pore size distribution than the coke obtained by traditional heating methods. Further activation can prepare activated carbon with superior adsorption performance, and it is more energy-saving and time-saving than traditional high-temperature direct activation.

Invention content:

The object of the present invention is to provide a kind of activated carbon preparation method using caragana as raw material, can produce the raw material of high-quality woody activated carbon with simple chemical activation method, and this raw material reserve is abundant, obtains easily, with low cost; The second aspect of the present invention The purpose is to obtain carbonized raw materials with more abundant pores and more uniform distribution through microwave cracking pretreatment of raw materials, and then high-temperature activation to obtain activated carbon with excellent adsorption performance, which is energy-saving and time-saving compared with traditional high-temperature activation, and provides a new way for the industrialization of activated carbon production.

The technical solution adopted by the present invention to solve its technical problems is:

(1) Pretreatment of Caragana: Cut Caragana into sections and initially carbonize it in a microwave pyrolysis reactor;

(2) After sieving the biomass coke, soak Caragana coke in 20-60wt.% phosphoric acid solution for 3-20 hours according to the carbon agent mass ratio of 1:1.0-1:2.0, and keep the temperature in the muffle furnace at 450-550°C Activated for 30-90 minutes under the same conditions, after cooling, washed with alkali and water until neutral, and dried to obtain a high-quality wood activated carbon.

The microwave cracking process is as follows: the reaction temperature is 450°C, the power is 2.0 kw, and the time is 5 min.

The alkaline washing solution is 3wt.% NaOH aqueous solution.

The drying process is performed at a temperature of 105° C. to an absolute dry state.

The specific method steps of preparing high-quality activated carbon with caragana as raw material are as follows:

(1) Microwave pretreatment (carbonization): Cut caragana into sections and put them into a quartz bottle, and react in a microwave cracking reaction furnace. The reaction conditions in the furnace are: temperature: 450°C, time: 5 min, power: 2 kw ;

(2) Sieving: crush Caragana coke and pass through a 200-mesh sieve;

(3) High temperature activation: Soak caragana coke in 20-60% phosphoric acid solution for 3-20 hours according to the mass ratio of charcoal agent 1:1.0-1:2.0, and dry the impregnated charcoal in an oven (105°C). After drying, gradually raise the temperature on the electric furnace to exhaust the smoke. After the smoke is exhausted, activate it in the muffle furnace at a constant temperature of 450-550°C for 30-90 minutes. After cooling, wash it with alkali and water to neutrality and dry it to obtain a High quality wood activated charcoal.

The main advantages of the present invention are as follows: First, caragana is rich in resources, easy to obtain, and rich in cellulose, hemicellulose and lignin, which can prepare woody activated carbon with high adsorption performance, and realize the recycling of abandoned agricultural and forestry crops ; Second, microwave pretreatment to obtain coke with rich pores and uniform distribution, which reduces the activation temperature and shortens the activation time, achieves the purpose of saving energy and time, and can realize the industrialization of caragana activated carbon. The activated carbon prepared by the present invention has good adsorption performance and well-developed pores. The optimal ash content and iodine adsorption value of Caragana activated carbon are 2.77%, 1213.37 mg.g ^-1 (>1000 mg.g ^-1 ).

Detailed ways

Example 1

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) Crush the coke and pass it through a 200-mesh sieve. Soak Caragana coke in 20wt.% phosphoric acid solution for 3 hours according to the ratio of carbon to agent 1:1.0. Dry the impregnated charcoal in an oven (105°C). Then gradually raise the temperature on the electric furnace to exhaust the smoke. After the smoke is exhausted, activate it in the muffle furnace at a constant temperature of 450 ° C for 30 min. After cooling, wash it with 3wt. Drying can produce a kind of high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 858.65 mg.g ^-1 .

Example 2

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) After crushing the coke, pass it through a 200-mesh sieve, soak Caragana coke in 40 wt.% phosphoric acid solution for 12 h according to the ratio of carbon to agent 1:1.0, and dry the impregnated charcoal in an oven (105°C). After drying, the temperature was gradually raised on the electric furnace to exhaust the smoke. After the smoke was exhausted, it was activated in the muffle furnace at a constant temperature of 500 ° C for 60 min. After cooling, it was washed with 3 wt.% NaOH aqueous solution and then washed with distilled water until neutral. Dry at 105°C to produce a high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 1168.12 mg.g ^-1 .

Example 3

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) Crush the coke and pass it through a 200-mesh sieve. Soak Caragana coke in 60 wt.% phosphoric acid solution for 20 hours according to the ratio of carbon to agent 1:1.0. Dry the impregnated charcoal in an oven (105°C). After drying, gradually raise the temperature on the electric furnace to exhaust the smoke. After the smoke is exhausted, activate it in the muffle furnace at a constant temperature of 550°C for 90 minutes. Drying can produce a kind of high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 1083.98 mg.g ^-1 .

Example 4

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) Crush the coke and pass it through a 200-mesh sieve. Soak Caragana coke in 20 wt.% phosphoric acid solution for 3 hours according to the ratio of carbon to agent 1:1.5. Dry the impregnated charcoal in an oven (105°C). After drying, the temperature was gradually raised on the electric furnace to exhaust the smoke. After the smoke was exhausted, it was activated in the muffle furnace at a constant temperature of 500 ° C for 60 min. After cooling, it was washed with 3 wt.% NaOH aqueous solution and then washed with distilled water until neutral. Dry at 105°C to produce a high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 1021.01 mg.g ^-1 .

Example 5

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) After crushing the coke, pass it through a 200-mesh sieve, soak Caragana coke in 40 wt.% phosphoric acid solution for 12 h according to the ratio of carbon to agent 1:1.5, and dry the impregnated charcoal in an oven (105°C). After drying, the temperature was gradually raised on the electric furnace to exhaust the smoke. After the smoke was exhausted, it was activated in the muffle furnace at a constant temperature of 500°C for 90 minutes. After cooling, it was washed with 3 wt.% NaOH aqueous solution, and then washed with distilled water until neutral. Dry at 105°C to produce a high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 1213.37 mg.g ^-1 .

Example 6

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 500°C, a power of 2 kw, and a time of 5 minutes;

(2) After crushing the coke, pass it through a 200-mesh sieve, soak Caragana coke in 60 wt.% phosphoric acid solution for 20 h according to the ratio of carbon to agent 1:1.5, and dry the impregnated charcoal in an oven (105°C). After drying, gradually raise the temperature on the electric furnace to exhaust the smoke. After the smoke is exhausted, activate it in the muffle furnace at a constant temperature of 450°C for 30 minutes. Drying can produce a kind of high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 956.44 mg.g ^-1 .

Example 7

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) After crushing the coke, pass it through a 200-mesh sieve, soak Caragana coke in 20 wt.% phosphoric acid solution for 12 h according to the ratio of carbon to agent 1:2.0, and dry the impregnated charcoal in an oven (105°C). After drying, the temperature was gradually raised on the electric furnace to exhaust the smoke. After the smoke was exhausted, it was activated in the muffle furnace at a constant temperature of 450°C for 90 minutes. After cooling, it was washed with 3 wt.% NaOH aqueous solution and then washed with distilled water until neutral. Dry at 105°C to produce a high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 949.80 mg.g ^-1 .

Example 8

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) Crush the coke and pass it through a 200-mesh sieve. Soak Caragana coke in 40 wt.% phosphoric acid solution for 20 h according to the ratio of carbon to agent 1:2.0. Dry the impregnated charcoal in an oven (105°C). After drying, gradually raise the temperature on the electric furnace to exhaust the smoke. After the smoke is exhausted, activate it in the muffle furnace at a constant temperature of 500°C for 30 min. After cooling, wash it with 3 wt. Dry at 105°C to produce a high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 1006.61 mg.g ^-1 .

Example 9

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) After crushing the coke, pass it through a 200-mesh sieve, soak Caragana coke in 60 wt.% phosphoric acid solution for 3 h according to the ratio of carbon to agent 1:2.0, and dry the impregnated charcoal in an oven (105°C). After drying, the temperature was gradually raised on the electric furnace to exhaust the smoke. After the smoke was exhausted, it was activated in the muffle furnace at a constant temperature of 550°C for 60 minutes. After cooling, it was washed with 3 wt.% NaOH aqueous solution, and then washed with distilled water until neutral. Dry at 105°C to produce a high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 1065.76 mg.g ^-1 .

Example 10

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) After crushing the coke, pass it through a 200-mesh sieve, soak Caragana coke in 20 wt.% phosphoric acid solution for 20 h according to the ratio of carbon to agent 1:1.0, and dry the impregnated charcoal in an oven (105°C). After drying, the temperature was gradually raised on the electric furnace to exhaust the smoke. After the smoke was exhausted, it was activated in the muffle furnace at a constant temperature of 550°C for 60 minutes. After cooling, it was washed with 3 wt.% NaOH aqueous solution, and then washed with distilled water until neutral. Dry at 105°C to produce a high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 824.88 mg.g ^-1 .

Example 11

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) After crushing the coke, pass it through a 200-mesh sieve, soak Caragana coke in 40 wt.% phosphoric acid solution for 3 h according to the ratio of carbon to agent 1:1.0, and dry the impregnated charcoal in an oven (105°C). After drying, the temperature was gradually raised on the electric furnace to exhaust the smoke. After the smoke was exhausted, it was activated in the muffle furnace at a constant temperature of 450°C for 90 minutes. After cooling, it was washed with 3 wt.% NaOH aqueous solution and then washed with distilled water until neutral. Dry at 105°C to produce a high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 833.38 mg.g ^-1 .

Example 12

(1) Cut Caragana bar into sections (about 2 cm), put it into a quartz reaction bottle, and carry out carbonization pretreatment in a microwave reaction furnace with a reaction temperature of 450°C, a power of 2 kw, and a time of 5 minutes;

(2) After crushing the coke, pass it through a 200-mesh sieve, soak Caragana coke in 60 wt.% phosphoric acid solution for 12 h according to the ratio of carbon to agent 1:1.0, and dry the impregnated charcoal in an oven (105°C). After drying, gradually raise the temperature on the electric furnace to exhaust the smoke. After the smoke is exhausted, activate it in the muffle furnace at a constant temperature of 500°C for 30 min. After cooling, wash it with 3 wt. Dry at 105°C to produce a high-quality wood activated carbon. The iodine adsorption value of activated carbon was determined to be 1206.38 mg.g ^-1 .

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (4)

1. take caragana as raw material's gac preparation method, it is characterized in that: comprise the steps: (1) Pretreatment of Caragana: Cut Caragana into sections and initially carbonize it in a microwave pyrolysis reactor; (2) After sieving the biomass coke, soak Caragana coke in 20-60wt.% phosphoric acid solution for 3-20 hours according to the carbon agent mass ratio of 1:1.0-1:2.0, and keep the temperature in the muffle furnace at 450-550°C Activated for 30-90 minutes under the same conditions, after cooling, washed with alkali and water until neutral, and dried to obtain a high-quality wood activated carbon. 2. The preparation method of activated carbon according to claim 1, characterized in that: the microwave cracking process is: reaction temperature 450°C, power 2.0 kw, time 5 min. 3. The preparation method of activated carbon according to claim 1, characterized in that: the alkaline washing solution is 3wt.%NaOH aqueous solution. 4. The method for preparing activated carbon according to claim 1, characterized in that: the drying process is performed at a temperature of 105° C. to an absolute dry state.