阅读说明：本技术 利用西红柿和茄子秸秆混合物制备生物活性炭的方法 (Method for preparing biological activated carbon by utilizing tomato and eggplant straw mixture ) 是由 孙晓丽 王淼 于 2019-10-25 设计创作，主要内容包括：本发明适用于生物活性炭制备技术领域,提供了一种利用西红柿和茄子秸秆混合物制备生物活性炭的方法,包括如下步骤：先将茄子秸秆和西红柿秸秆洗净粉碎混合,再用焦磷酸进行浸泡活化,活化后放入管式炉炭化,然后回收焦磷酸并漂洗,最后脱水、干燥、粉碎后得到生物活性炭。借此,本发明制备工艺简单,生产成本低,效率高,制得的生物活性炭吸附力强,适合去除大分子有害污染物。(The invention is suitable for the technical field of preparation of biological activated carbon, and provides a method for preparing biological activated carbon by utilizing a tomato and eggplant straw mixture, which comprises the following steps: cleaning, crushing and mixing eggplant straws and tomato straws, soaking and activating the eggplant straws and the tomato straws by using pyrophosphoric acid, putting the eggplant straws and the tomato straws into a tubular furnace for carbonization after activation, then recovering and rinsing the pyrophosphoric acid, and finally dehydrating, drying and crushing the pyrophosphoric acid to obtain the biological activated carbon. Therefore, the preparation method disclosed by the invention is simple in preparation process, low in production cost, high in efficiency, strong in adsorption capacity of the prepared biological activated carbon, and suitable for removing macromolecular harmful pollutants.)

1. A method for preparing biological activated carbon by utilizing a tomato and eggplant straw mixture is characterized by comprising the following steps:

step one pretreatment

Cleaning eggplant straws and tomato straws, respectively drying and crushing the eggplant straws and the tomato straws at the temperature of 80-100 ℃, sieving the eggplant straws and the tomato straws with a 45-mesh sieve, and then mixing the eggplant straws and the tomato straws to obtain straw mixed particles;

step two soaking activation

Mixing the straw mixed particles with 50-65% of pyrophosphoric acid according to the weight ratio of 1: 1-1.2, and soaking; in the soaking process, adding the pyrophosphoric acid while stirring, uniformly mixing, performing ultrasonic treatment for 15-20 min, and standing for 8.5-10 h to obtain a first material;

charring in the third step

Putting the first material into a tubular furnace, introducing nitrogen, heating the interior of the tubular furnace, keeping the temperature constant when the temperature is increased to 450-500 ℃, continuing to carbonize for 0.5-1 h, stopping heating, and cooling to room temperature to obtain a second material;

step four recovery of Pyrophosphoric acid

Extracting the second material with a 35-45% pyrophosphoric acid solution, continuously extracting with a 15-25% pyrophosphoric acid solution after the first extraction is completed, continuously extracting with a 5-20% pyrophosphoric acid solution after the second extraction is completed, and washing with 35-45 ℃ water to enable the content of pyrophosphoric acid in the second material to be lower than 1% to obtain a third material;

rinsing in step five

Putting the third material into a rinsing barrel, adding a proper amount of pyrophosphoric acid with the volume concentration of 15-25%, introducing steam into the rinsing barrel, and boiling for 2-3 hours to obtain a fourth material;

adding alkali into the material IV to neutralize pyrophosphoric acid with the volume concentration of 15-25% to generate phosphate ions, washing with water at 35-45 ℃ to remove water-soluble impurities, and washing with water until the content of the phosphate ions in the material IV is lower than 0.16% to obtain a material V;

step six, dehydrating, drying and crushing

And dehydrating the material V, drying and then crushing to obtain the biological activated carbon.

2. The method for preparing the biological activated carbon by using the mixture of tomatoes and eggplant straws as claimed in claim 1, wherein the mass ratio of the eggplant straws to the tomato straws is 1: 1-2.

3. The method for preparing biological activated carbon by using the mixture of tomato and eggplant straws as claimed in claim 1, wherein in the second step, the pH value of the pyrophosphoric acid is 2.5-3.5.

4. The method for preparing biological activated carbon by utilizing the mixture of tomato and eggplant straws as claimed in claim 1, wherein in the third step, the temperature rise speed is 10 ℃/min during the temperature rise inside the tube furnace.

5. The method for preparing biological activated carbon by using the mixture of tomato and eggplant straws as claimed in claim 1, wherein the nitrogen gas is introduced at a rate of 2L/min.

6. The method for preparing biological activated carbon by using the mixture of tomato and eggplant straws as claimed in claim 1, wherein in the fourth step, the total time for recovering the pyrophosphoric acid is 1.5-4 h.

7. The method for preparing biological activated carbon by using the mixture of tomato and eggplant straws as claimed in claim 1, wherein in the fifth step, the alkali is any one of sodium hydroxide or potassium hydroxide.

8. The method for preparing biological activated carbon by utilizing the mixture of tomato and eggplant straws as claimed in claim 1, wherein in the sixth step, the moisture content of the material five after being dried is lower than 10%.

9. The method for preparing the biological activated carbon by using the mixture of the tomato and the eggplant straw as claimed in any one of claims 1 to 8, wherein the yield of the biological activated carbon is 30 to 50%.

Technical Field

The invention relates to the technical field of preparation of biological activated carbon, in particular to a method for preparing biological activated carbon by utilizing a tomato and eggplant straw mixture.

Background

The activated carbon is an excellent adsorbent material, has large specific surface area, developed pores, high adsorption and desorption speed, strong regeneration capacity, large adsorption capacity and good adsorption dynamic performance, and is widely applied to the fields of environmental protection, chemical industry, military chemical protection, chemical power supply and the like. The raw materials for preparing the active carbon mainly comprise coal, petroleum coke and wood; in recent years, in order to reduce the price of activated carbon, researchers mostly use agricultural solid wastes such as cotton stalks, corn stalks, peanut shells and the like to prepare activated carbon. Tomatoes and eggplants are global crops, and a large amount of straws are produced every year, but no way for industrial utilization exists, so that the tomatoes and the eggplants need to be recycled and commercialized.

In view of the above, the prior art is obviously inconvenient and disadvantageous in practical use, and needs to be improved.

Disclosure of Invention

Aiming at the defects, the invention aims to provide the method for preparing the biological activated carbon by utilizing the mixture of the tomato and the eggplant straw, the preparation process is simple, the production cost is low, the efficiency is high, and the prepared biological activated carbon has strong adsorption capacity and is suitable for removing macromolecular harmful pollutants.

In order to achieve the aim, the invention provides a method for preparing biological activated carbon by using a tomato and eggplant straw mixture, which comprises the following steps:

step one pretreatment

Cleaning eggplant straws and tomato straws, respectively drying and crushing the eggplant straws and the tomato straws at the temperature of 80-100 ℃, sieving the eggplant straws and the tomato straws with a 45-mesh sieve, and then mixing the eggplant straws and the tomato straws to obtain straw mixed particles.

Step two soaking activation

Mixing the straw mixed particles with 50-65% of pyrophosphoric acid according to the weight ratio of 1: 1-1.2, and soaking; in the soaking process, adding the pyrophosphoric acid while stirring, uniformly mixing, performing ultrasonic treatment for 15-20 min, and standing for 8.5-10 h to obtain a material I.

Charring in the third step

And putting the first material into a tubular furnace, introducing nitrogen, heating the interior of the tubular furnace, keeping the temperature constant when the temperature is increased to 450-500 ℃, continuing to carbonize for 0.5-1 h, stopping heating, and cooling to room temperature to obtain a second material.

Step four recovery of Pyrophosphoric acid

Extracting the second material with a 35-45 vol% pyrophosphoric acid solution, extracting the second material with a 15-25 vol% pyrophosphoric acid solution after the first extraction is completed, extracting the second material with a 5-20 vol% pyrophosphoric acid solution after the second extraction is completed, and washing the second material with 35-45 ℃ water to enable the content of pyrophosphoric acid in the second material to be lower than 1% to obtain a third material.

Rinsing in step five

Putting the third material into a rinsing barrel, adding a proper amount of pyrophosphoric acid with the volume concentration of 15-25%, introducing steam into the rinsing barrel, and boiling for 2-3 hours to obtain a fourth material;

and adding alkali into the material IV to neutralize pyrophosphoric acid with the volume concentration of 15-25% to generate phosphate ions, washing with water at 35-45 ℃ to remove water-soluble impurities, and washing with water until the content of the phosphate ions in the material IV is lower than 0.16% to obtain a material V.

Step six, dehydrating, drying and crushing

And dehydrating the material V, drying and then crushing to obtain the biological activated carbon.

According to the method for preparing the biological activated carbon by using the mixture of the tomatoes and the eggplant straws, the mass ratio of the eggplant straws to the tomato straws is 1: 1-2.

According to the method for preparing the biological activated carbon by using the tomato and eggplant straw mixture, in the second step, the pH value of the pyrophosphoric acid is 2.5-3.5.

According to the method for preparing the biological activated carbon by utilizing the tomato and eggplant straw mixture, in the third step, the temperature rising speed is 10 ℃/min in the temperature rising process in the tubular furnace.

According to the method for preparing the biological activated carbon by utilizing the tomato and eggplant straw mixture, the nitrogen gas is introduced at the speed of 2L/min.

According to the method for preparing the biological activated carbon by utilizing the tomato and eggplant straw mixture, the total time for recovering the pyrophosphoric acid in the fourth step is 1.5-4 hours.

According to the method for preparing the biological activated carbon by using the tomato and eggplant straw mixture, in the fifth step, the alkali is any one of sodium hydroxide or potassium hydroxide.

According to the method for preparing the biological activated carbon by using the tomato and eggplant straw mixture, in the sixth step, the moisture content of the material five after being dried is lower than 10%.

According to the method for preparing the biological activated carbon by using the tomato and eggplant straw mixture, the yield of the biological activated carbon is 30-50%.

The invention aims to provide a method for preparing biological activated carbon by utilizing a mixture of tomatoes and eggplant straws, wherein the eggplant straws and the tomato straws are used as raw materials, so that waste utilization, resource circulation and low production cost are realized; eggplant straws and tomato straws are crushed into particles, and then are soaked and activated by pyrophosphoric acid, the activation process is simple, pyrophosphoric acid molecules can quickly enter the straws, and finally disordered-layer microcrystalline structures with developed pores are formed; and putting the activated carbon into a tubular furnace for carbonization, then recovering and rinsing pyrophosphoric acid, and finally dehydrating, drying and crushing the pyrophosphoric acid to obtain the biological activated carbon, wherein the activated carbon has large specific surface area and developed pores. In conclusion, the beneficial effects of the invention are as follows: the preparation process is simple, the production cost is low, the efficiency is high, and the prepared biological activated carbon has strong adsorption capacity and is suitable for removing macromolecular harmful pollutants.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a method for preparing biological activated carbon by utilizing a tomato and eggplant straw mixture, which comprises the following steps:

step one pretreatment

Cleaning eggplant straws and tomato straws, drying and crushing at 80-100 ℃, sieving with a 45-mesh sieve, and then mixing to obtain straw mixed particles. According to the invention, the mass ratio of the eggplant straws to the tomato straws is 1: 1-2.

The kind of raw materials has great influence on the adsorption performance of the activated carbon. The straw mixed raw material integrates the advantages of various plant straws, the proportion is scientific and reasonable, and the activated carbon with better quality can be produced by optimizing the process conditions.

Step two soaking activation

Mixing the straw mixed particles with pyrophosphoric acid according to a weight ratio of 1: 1-1.2, soaking, adding pyrophosphoric acid while stirring in the soaking process, uniformly mixing, performing ultrasonic treatment for 15-20 min, and standing for 8.5-10 h to obtain a material I. The pH value of the pyrophosphoric acid is 2.5-3.5, and the volume concentration is 50-65%.

The main chemical components of the straw mixed particles are saccharides, namely carbohydrates such as cellulose, hemicellulose and pectin, when the pyrophosphoric acid solution is soaked and kneaded, the cellulose and other components swell and simultaneously undergo hydrolysis reaction and oxidation reaction, the cellulose can be dispersed into a peptized state, and the high molecular compounds are depolymerized into smaller molecules, so that the straw mixed particles have plasticity and viscosity, and finally form a disordered-layer microcrystalline structure with developed pores.

Charring in the third step

Putting the first material into a tubular furnace, introducing nitrogen, heating the interior of the tubular furnace at a heating speed of 10 ℃/min, keeping the temperature constant when the temperature is increased to 450-500 ℃, continuing to carbonize for 0.5-1 h, stopping heating, and cooling to room temperature to obtain a second material; and taking out the second material for later use.

The nitrogen gas is introduced at a rate of 2L/min in a mode of horizontally introducing from the left side to the right side of the tubular furnace, and the nitrogen gas is not stopped and the introduction amount is stabilized during 0.5-1 h of carbonization.

The pyrophosphoric acid makes the straw mixed particles collosol into plastic colloidal substances, and then the plastic colloidal substances are uniformly distributed in the raw materials, organic matters are decomposed during carbonization, the pyrophosphoric acid becomes the surface on which the pyrolytic carbon is deposited, when the pyrophosphoric acid and water are dissolved, the surface of the carbon is exposed to form the inner surface area of the activated carbon, and the space occupied by the original pyrophosphoric acid becomes the pore structure of the activated carbon.

Step four recovery of Pyrophosphoric acid

Extracting a second material with a 35-45% pyrophosphoric acid solution, continuously extracting with a 15-25% pyrophosphoric acid solution after the first extraction is completed, continuously extracting with a 5-20% pyrophosphoric acid solution after the second extraction is completed, and washing with hot water after multiple extractions until the content of pyrophosphoric acid in the second material is lower than 1% to obtain a third material;

the total time for recovering the pyrophosphoric acid is 1.5-4 h; zinc sulfate is added into the recovered pyrophosphoric acid solution to remove impurities, and the pyrophosphoric acid solution after the impurities are removed can be recycled.

The temperature of the hot water is 35-45 ℃.

Rinsing in step five

Putting the third material into a rinsing barrel, adding a proper amount of pyrophosphoric acid with the volume concentration of 15-25%, introducing steam into the rinsing barrel, boiling for 2-3 hours to change water-insoluble impurities in the third material into water-soluble compounds, and removing the water-soluble compounds to obtain a fourth material;

and adding alkali into the material IV to neutralize pyrophosphoric acid with the volume concentration of 15-25% to generate phosphate ions, washing with hot water to remove water-soluble impurities, and washing with water until the content of the phosphate ions in the material IV is lower than 0.16% to obtain a material V. The alkali may be any one of sodium hydroxide and potassium hydroxide.

Step six, dehydrating, drying and crushing

Placing the material five into a centrifuge for dehydration to enable the moisture content in the material five to be lower than 60-65%; and then drying to ensure that the moisture content in the material five is lower than 10 percent. And (3) crushing the dried material V by using a continuous ball mill to obtain the biological activated carbon, wherein the yield of the biological activated carbon is 30-50%.

In order to verify the method for preparing the bio-activated carbon according to the present invention, the present invention provides the following examples.