An activated carbon material for adsorbing heavy metals in soil and its manufacturing process

Abstract

The present invention relates to the technical field of soil heavy metal adsorption, and discloses an activated carbon material for adsorbing soil heavy metals and its manufacturing process. The activated carbon material is obtained by modifying activated carbon to obtain modified activated carbon with a large specific surface area, rich pores, and many adsorption sites. Its surface is provided with carboxylic acid groups and sulfonic acid groups to adsorb heavy metals, reducing the water-soluble state and exchangeable state contents of heavy metals; by modifying tourmaline powder, a mineral additive component containing rich chelating groups is obtained, which produces a chelating effect with heavy metals, can also increase the soil pH value, promote the soil to be neutral, reduce the mobility, available state content, and bioavailability of heavy metals. Therefore, the activated carbon material prepared by the present invention has excellent heavy metal adsorption effect, and is especially suitable for acidified heavy metal soil.

Description

Technical Field

[0001] The present invention relates to the technical field of soil heavy metal adsorption, and particularly relates to an activated carbon material for adsorbing soil heavy metals and a manufacturing process thereof. Background Art

[0002] Soil is an important part of the natural ecosystem, an important natural resource for humans, and the cornerstone of agricultural production. It is crucial for survival and development. In recent years, with the continuous development of urbanization and industrialization, agricultural sewage irrigation, mine waste, heavy metals entering the soil through atmospheric deposition, and the abuse of pesticides and fertilizers have led to the accumulation of heavy metal pollution in the soil. Heavy metals include cadmium, lead, chromium, copper, mercury, etc., which are characterized by being difficult to degrade, easy to accumulate, and highly toxic. Once the concentration of heavy metals in the soil exceeds the purification and accommodation capacity of the soil itself, it will cause damage to the soil structure, reduction of biodiversity, and ecological imbalance, affecting the growth and quality of crops, reducing agricultural productivity, and being able to accumulate in the human body through the food chain and interact with biomolecules in the body, posing a threat to human life and health. Therefore, the adsorption of soil heavy metals is crucial for protecting human health and the ecological environment and is of great research significance.

[0003] Activated carbon is a common adsorbent that can be used for air purification, gas separation, and the adsorption of heavy metals in water bodies or soils. It has a variety of rich functional groups on its surface, a developed pore structure, a large specific surface area, stable properties, acid and alkali resistance, and renewable advantages. However, the adsorption capacity of activated carbon is limited and it is easy to become saturated. Therefore, the adsorption effect on heavy metals is poor, and its effect on reducing the available state of heavy metal ions in acidified soil is limited. For the patent with the publication number CN109231758B, a modified sludge activated carbon heavy metal adsorption material is disclosed. Through three steps of phosphoric acid activation treatment, activation treatment, and modification treatment, the adsorption effect on heavy metal ions is improved. The prepared adsorption material has micropores, mesopores, and macropores. It not only has an adsorption effect on heavy metal ions but also can expand the scope of use and has a high adsorption effect on macromolecular pollutants. The performance of the adsorption material is stable, realizing the recyclable utilization and resource utilization of the bottom mud. However, this patent does not consider that the available state of heavy metals will increase in acidified soil and the adsorption capacity of modified sludge activated carbon will decrease. Therefore, the present invention provides an activated carbon material that can play an excellent role in adsorbing heavy metals in acidic soil. Summary of the Invention

[0004] In order to solve the problems mentioned in the background art, the purpose of the present invention is to provide an activated carbon material for adsorbing soil heavy metals and a manufacturing process thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] An activated carbon material for adsorbing heavy metals in soil, comprising raw materials in the following parts by weight: 35-50 parts of modified activated carbon, 10-15 parts of mineral additive components, 4-8 parts of natural composite glue, 2-4 parts of calcium carbonate, and 3-6 parts of zeolite powder.

[0007] Furthermore, the preparation method of the modified activated carbon comprises the following steps:

[0008] Step S1: Add activated carbon into concentrated nitric acid, stir and mix for 2-4 h, then filter, wash, and dry to obtain pretreated activated carbon;

[0009] Step S2: Add the pretreated activated carbon and polyaspartic acid into N,N-dimethylformamide, mix evenly, ultrasonically vibrate for 10-30 min, then add 3-hydroxypropanesulfonic acid, dicyclohexylcarbodiimide, and 4-dimethylaminopyridine into it, start stirring, control the stirring rate at 500-650 r / min, stir for 4-6 h, then separate the product, wash, and dry to obtain modified activated carbon.

[0010] By adopting the above technical solution, after the activated carbon is treated with concentrated nitric acid, surface impurities are removed, the specific surface area and pore volume increase, and the oxygen-containing groups increase. Polyaspartic acid can act with the oxygen-containing groups on the surface of the activated carbon to realize the modification of the activated carbon by polyaspartic acid. Under the action of dicyclohexylcarbodiimide and 4-dimethylaminopyridine, the hydroxyl group in the structure of 3-hydroxypropanesulfonic acid can react with the carboxyl group in the structure of polyaspartic acid to obtain modified activated carbon. The modified activated carbon prepared in the present invention uses activated carbon as the matrix. The activated carbon has a large specific surface area and a rich pore structure. The surface of the modified activated carbon contains a large number of carboxyl groups and sulfonate groups, effectively increasing the adsorption sites for heavy metals on the activated carbon, thereby improving the ability of the activated carbon to adsorb heavy metals. In the subsequent use process, carboxylic acid groups and sulfonate groups are used to adsorb heavy metals and act with heavy metals, reducing the water-soluble state and exchangeable state content of heavy metals, achieving the purpose of fixing heavy metals, and having the effect of stably and efficiently adsorbing heavy metals.

[0011] Furthermore, in step S1, the mass fraction of the concentrated nitric acid is 60-65%.

[0012] Furthermore, in step S2, the ultrasonic frequency during ultrasonic vibration is 60-80 kHz.

[0013] Furthermore, the preparation method of the mineral additive components comprises the following steps:

[0014] Step T1: Disperse tourmaline powder in dimethyl sulfoxide to form a uniform dispersion liquid, add mercapto succinic acid and a catalyst, stir and mix evenly, then raise the temperature to 90-95 °C, react for 3-5 h, then filter, wash, and dry to obtain modified tourmaline powder;

[0015] Step T2: Add the modified tourmaline powder into N,N-dimethylformamide. After dispersing it evenly, add the aminopyridine compound, dicyclohexylcarbodiimide, and 4-dimethylaminopyridine. After reacting for 3-5 h, discharge the material, wash it, and dry it to obtain the mineral additive component.

[0016] By adopting the above technical solution, the hydroxyl groups on the surface of the tourmaline powder can undergo an esterification reaction with the carboxyl groups in the structure of mercaptosuccinic acid under the action of a catalyst to obtain the modified tourmaline powder with carboxyl and mercapto groups on the surface. Under the action of dicyclohexylcarbodiimide and 4-dimethylaminopyridine, the carboxyl groups on the surface of the modified tourmaline powder can undergo an amidation reaction with the amino groups in the structure of the aminopyridine compound to obtain the mineral additive component. The mineral additive component prepared by the present invention modifies the tourmaline powder. The tourmaline powder can adsorb heavy metals in the soil through ion exchange. After modification, mercapto, amide, and pyridine groups are introduced on the surface of the tourmaline powder. These groups can all chelate with heavy metals in the soil, adsorb and fix heavy metal ions in the soil. The tourmaline powder and the introduced pyridine groups can effectively increase the pH value of the soil, make the soil show neutrality, increase the affinity of the soil for heavy metals, passivate heavy metals in the soil, reduce the mobility and available state content of heavy metals in the soil, thereby reducing the bioavailability of heavy metals in the soil. The fixation effect on soil heavy metals is stable and will not cause secondary pollution. It has a synergistic effect with the modified activated carbon and improves the adsorption capacity of the activated carbon material for heavy metals.

[0017] Further, in step T1, the catalyst is p-toluenesulfonic acid or calcium methylsulfonate.

[0018] Further, in step T2, the aminopyridine compound is any one of 2-aminopyridine, 3-aminopyridine, or 4-aminopyridine.

[0019] Further, the preparation method of the natural composite glue is as follows:

[0020] Add agar and arabinoxylan into deionized water. Raise the temperature to 60-70 °C. After stirring and mixing for 0.5-1 h, add sodium tripolyphosphate and continue stirring for 2-4 h. Wait until it cools to room temperature, then discharge the material to obtain the natural composite glue.

[0021] By adopting the above technical solution, sodium tripolyphosphate is used to promote the cross-linking of the hydroxyl groups in the structures of agar and arabinoxylan to obtain the natural composite glue. The natural composite glue prepared by the present invention has a cross-linked network structure, which greatly improves the bonding strength and avoids using natural agar or arabinoxylan alone as an adhesive, resulting in insufficient bonding strength and causing blockage of the pores of the modified activated carbon, mineral additive component, and zeolite powder, thereby having a negative impact on the adsorption of soil heavy metals.

[0022] A manufacturing process of an activated carbon material for adsorbing heavy metals in soil, comprising the following steps:

[0023] Step 1: Add modified activated carbon, mineral additive components, calcium carbonate and zeolite powder into a blender. After stirring and mixing for 10 - 30 min, add natural composite glue, keep the stirring rate unchanged, and continue to stir for 1 - 3 h to obtain a mixed base material;

[0024] Step 2: Put the mixed base material into a mold, after extrusion molding, place it in a drying oven, dry it at a temperature of 70 - 90 °C for 4 - 6 h, and then cool it to room temperature to obtain the activated carbon material.

[0025] Further, in Step 1, the stirring rate is 150 - 300 r / min.

[0026] Advantages of the present invention:

[0027] By modifying the activated carbon, the present invention obtains modified activated carbon containing carboxyl and sulfonic acid groups, increasing the adsorption sites, improving the ability to adsorb heavy metals, reducing the water-soluble state and exchangeable state content of heavy metals. By modifying tourmaline powder, it can chelate with heavy metals, increase the soil pH value, passivate soil heavy metals, reduce the mobility and available state content of soil heavy metals, and has a synergistic effect with the modified activated carbon, increasing the adsorption amount of heavy metals. Furthermore, the prepared activated carbon material has excellent heavy metal adsorption effect, and is especially suitable for acidified heavy metal soil.

[0028] Of course, it is not necessary for any product implementing the present invention to simultaneously achieve all the above-mentioned advantages. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 It is the infrared spectrogram of the mineral additive components in the present invention. Specific Embodiments

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0032] The preparation methods of the modified activated carbon, mineral additive components and natural composite rubber in the following examples and comparative examples are as follows:

[0033] I. Preparation of modified activated carbon

[0034] Step S1: Add 5.2 g of activated carbon into concentrated nitric acid with a mass fraction of 65%, stir and mix for 3 h, then filter, wash and dry to obtain pretreated activated carbon;

[0035] Step S2: Add 5 g of pretreated activated carbon and 3.6 g of polyaspartic acid into N,N-dimethylformamide, mix evenly, ultrasonically vibrate at a frequency of 60 kHz for 20 min, then add 2 g of 3-hydroxypropanesulfonic acid, 0.4 g of dicyclohexylcarbodiimide and 0.2 g of 4-dimethylaminopyridine, start stirring, control the stirring rate at 600 r / min, stir for 5 h, then separate the product, wash and dry to obtain modified activated carbon.

[0036] Use a Perkin-Elmer 2400 type elemental analyzer to analyze the activated carbon and the modified activated carbon. From the results, it can be seen that the activated carbon does not contain nitrogen and sulfur elements, the nitrogen element percentage content in the modified activated carbon is 4.63%, and the sulfur element percentage content is 3.25%. Therefore, it can be known that polyaspartic acid and 3-hydroxypropanesulfonic acid react and successfully modify the activated carbon.

[0037] II. Preparation of mineral additive components

[0038] Step T1: Disperse 3.6 g of tourmaline powder in dimethyl sulfoxide to form a uniform dispersion, add 2.4 g of mercaptosuccinic acid and 0.5 g of p-toluenesulfonic acid, stir and mix evenly, then raise the temperature to 90 °C, react for 4 h, filter by suction, wash and dry to obtain modified tourmaline powder;

[0039] Step T2: Add 3.2 g of modified tourmaline powder into N,N-dimethylformamide, disperse evenly, then add 2 g of 3-aminopyridine, 0.3 g of dicyclohexylcarbodiimide and 0.1 g of 4-dimethylaminopyridine, react for 4 h, then discharge, wash and dry to obtain mineral additive components.

[0040] Use a Fourier transform infrared spectrometer to perform infrared testing on the mineral additive components, as Figure 1As shown, it can be analyzed that in the infrared spectrum of the mineral additive component, an absorption peak of N-H in the amide appears at 3425 cm -1 ; an absorption peak of S-H in the mercapto group appears at 2524 cm -1 ; an absorption peak of C=O in the ester group appears at 1728 cm -1 ; an absorption peak of C=O in the amide appears at 1662 cm -1 ; an absorption peak of C-N appears at 1430 cm -1 ; an absorption peak of B-O appears at 1276 cm -1 ; and an absorption peak of Si-O appears at 1004 cm -1 .

[0041] III. Preparation of Natural Composite Gum

[0042] Add 2.5 g of agar and 2.5 g of arabinoxylan to deionized water, raise the temperature to 65 °C, stir and mix for 1 h, then add 1.4 g of sodium tripolyphosphate, continue to stir for 3 h, wait until it cools to room temperature, and discharge to obtain natural composite gum.

[0043] Use a universal testing machine to conduct a 180° peel test on tinplates coated with natural composite gum, agar, and arabinoxylan on one side. Attach the tinplates coated with natural composite gum, agar, and arabinoxylan on one side to the tape, stick double-sided tape on the other side of the tinplate, fix it on a glass slide, and detect the bonding performance. The test results are shown in the following table:

[0044] Agar Arabinoxylan Natural compound gum Peeling force (N / cm) 1.32 1.28 3.62

[0045] As can be seen from the above table, the structure of the natural composite gum contains a cross-linked network structure. Therefore, its bonding performance is stronger than that of agar and arabinoxylan, and it can firmly and stably bond modified activated carbon, mineral additive components, calcium carbonate, and zeolite powder with a small amount of addition.

[0046] Example 1

[0047] Manufacture of Activated Carbon Material

[0048] Step 1: Add 35 g of modified activated carbon, 10 g of mineral additive component, 3 g of calcium carbonate, and 4 g of zeolite powder to a blender, stir and mix at a stirring rate of 150 r / min for 10 min, then add 4 g of natural composite gum, keep the stirring rate unchanged, and continue to stir for 1 h to obtain a mixed base material;

[0049] Step 2: Put the mixed base material into a mold, after extrusion molding, place it in a drying oven, dry at a temperature of 70 °C for 4 h, and then cool to room temperature to obtain the activated carbon material.

[0050] Example 2

[0051] Manufacture of Activated Carbon Material

[0052] Step 1: Add 40 g of modified activated carbon, 12 g of mineral additive components, 3 g of calcium carbonate, and 4 g of zeolite powder into a blender. Stir and mix at a stirring rate of 200 r / min for 15 min. Then add 5 g of natural composite glue, keep the stirring rate unchanged, and continue to stir for 1.5 h to obtain a mixed base material;

[0053] Step 2: Put the mixed base material into a mold. After extrusion molding, place it in a drying oven and dry at a temperature of 80 °C for 4.5 h, then cool to room temperature to obtain the activated carbon material.

[0054] Example 3

[0055] Manufacture of Activated Carbon Material

[0056] Step 1: Add 45 g of modified activated carbon, 14 g of mineral additive components, 3 g of calcium carbonate, and 4 g of zeolite powder into a blender. Stir and mix at a stirring rate of 250 r / min for 20 min. Then add 6 g of natural composite glue, keep the stirring rate unchanged, and continue to stir for 2 h to obtain a mixed base material;

[0057] Step 2: Put the mixed base material into a mold. After extrusion molding, place it in a drying oven and dry at a temperature of 85 °C for 5 h, then cool to room temperature to obtain the activated carbon material.

[0058] Example 4

[0059] Manufacture of Activated Carbon Material

[0060] Step 1: Add 50 g of modified activated carbon, 15 g of mineral additive components, 4 g of calcium carbonate, and 6 g of zeolite powder into a blender. Stir and mix at a stirring rate of 300 r / min for 30 min. Then add 8 g of natural composite glue, keep the stirring rate unchanged, and continue to stir for 3 h to obtain a mixed base material;

[0061] Step 2: Put the mixed base material into a mold. After extrusion molding, place it in a drying oven and dry at a temperature of 90 °C for 6 h, then cool to room temperature to obtain the activated carbon material.

[0062] Comparative Example 1

[0063] Manufacture of Activated Carbon Material

[0064] Step 1: Add 45 g of modified activated carbon, 3 g of calcium carbonate, and 4 g of zeolite powder into a blender. Stir and mix at a stirring rate of 250 r / min for 20 min. Then add 6 g of natural composite glue, keep the stirring rate unchanged, and continue to stir for 2 h to obtain a mixed base material;

[0065] Step 2: Put the mixed base material into a mold. After extrusion molding, place it in a drying oven and dry it at a temperature of 85°C for 5 hours, then cool it to room temperature to obtain the activated carbon material.

[0066] Comparative Example 2

[0067] Manufacture of Activated Carbon Material

[0068] Step 1: Add 45 g of activated carbon, 14 g of mineral additive components, 3 g of calcium carbonate, and 4 g of zeolite powder to a blender. Stir and mix at a stirring rate of 250 r / min for 20 minutes, then add 6 g of natural composite glue. Keep the stirring rate unchanged and continue to stir for 2 hours to obtain the mixed base material;

[0069] Step 2: Put the mixed base material into a mold. After extrusion molding, place it in a drying oven and dry it at a temperature of 85°C for 5 hours, then cool it to room temperature to obtain the activated carbon material.

[0070] Comparative Example 3

[0071] Manufacture of Activated Carbon Material

[0072] Step 1: Add 45 g of modified activated carbon, 14 g of tourmaline powder, 3 g of calcium carbonate, and 4 g of zeolite powder to a blender. Stir and mix at a stirring rate of 250 r / min for 20 minutes, then add 6 g of natural composite glue. Keep the stirring rate unchanged and continue to stir for 2 hours to obtain the mixed base material;

[0073] Step 2: Put the mixed base material into a mold. After extrusion molding, place it in a drying oven and dry it at a temperature of 85°C for 5 hours, then cool it to room temperature to obtain the activated carbon material.

[0074] Comparative Example 4

[0075] Manufacture of Activated Carbon Material

[0076] Step 1: Add 45 g of activated carbon, 3 g of calcium carbonate, and 4 g of zeolite powder to a blender. Stir and mix at a stirring rate of 250 r / min for 20 minutes, then add 6 g of natural composite glue. Keep the stirring rate unchanged and continue to stir for 2 hours to obtain the mixed base material;

[0077] Step 2: Put the mixed base material into a mold. After extrusion molding, place it in a drying oven and dry it at a temperature of 85°C for 5 hours, then cool it to room temperature to obtain the activated carbon material.

[0078] Detection

[0079] Take the acidified heavy metal soil, remove the impurities in the soil, air-dry and crush it, and pass it through an 80-mesh sieve to obtain the test soil.

[0080] a: Add the test soil to deionized water to prepare a 1000 mL mixture with a solid content of 400 g / L. Use a soil pH tester to measure the initial pH value of the test soil, and divide it evenly into 8 test groups. Add 4 g of the activated carbon materials prepared in Examples 1 - 4 and Comparative Examples 1 - 4 to each test group, mix evenly, place them in a shaking box, shake at room temperature for 16 h, then let it stand. Take the supernatant when it is 15 days and 45 days, and use a soil pH tester to measure the pH value of the test group. The test results are shown in Table 1:

[0081] Table 1

[0082] Initial pH pH after 15 days pH after 45 days Example 1 4.92 5.72 6.95 Example 2 4.92 5.78 7.01 Example 3 4.92 5.80 7.03 Example 4 4.92 5.75 6.98 Comparative Example 1 4.92 5.22 5.33 Comparative Example 2 4.92 5.68 6.93 Comparative Example 3 4.92 5.41 6.15 Comparative Example 4 4.92 5.13 5.25

[0083] As can be seen from Table 1, the activated carbon materials prepared in Examples 1 - 4 of the present invention can increase the pH value of acidified heavy metal soil. In Comparative Example 1 and Comparative Example 4, no mineral additive was added, so the effect of increasing the pH value is very poor. In Comparative Example 3, unmodified tourmaline powder was added, and the effect of increasing the pH value is relatively poor.

[0084] b: Add the test soil to deionized water to prepare a 1000 mL mixture with a solid content of 400 g / L. Add 6 mL of 1 mol / L hydrochloric acid to the mixture, stir for 90 min, then test the heavy metal ion content as M0. Then divide it evenly into 8 test groups, and add 4 g of the activated carbon materials prepared in Examples 1 - 4 and Comparative Examples 1 - 4 of the present invention to the test groups respectively, stir evenly, let it stand for one week, take the supernatant, and test the heavy metal ion content again as M1. According to the adsorption rate = [(M0 - M1) / M0]×100%, the results are shown in Table 2:

[0085] Table 2

[0086] Adsorption rate / % Example 1 97.4 Example 2 97.9 Example 3 98.2 Example 4 97.6 Comparative Example 1 78.5 Comparative Example 2 75.6 Comparative Example 3 80.4 Comparative Example 4 62.2

[0087] As can be seen from Table 2, the activated carbon materials prepared in Examples 1 - 4 of the present invention have excellent heavy metal adsorption effects. In Comparative Example 1, modified activated carbon was added without mineral additive components, and the rich chelating groups in the mineral additive components cannot be used to adsorb heavy metals, so the heavy metal adsorption amount is small and the adsorption effect is poor; in Comparative Example 2, activated carbon and mineral additive components were added, but the activated carbon was not modified, with few adsorption sites and low adsorption capacity, so the adsorption effect is poor; in Comparative Example 3, modified activated carbon and tourmaline powder were added, and there are no chelating groups on the surface of the tourmaline powder, and the adsorption ability for heavy metals is poor, so the adsorption effect is poor; in Comparative Example 4, only activated carbon was added, and the adsorption effect is the worst.

[0088] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.

Claims

1. An activated carbon material for adsorbing heavy metals in soil, characterized in that, It comprises the following raw materials in parts by weight: 35 - 50 parts of modified activated carbon, 10 - 15 parts of mineral additive component, 4 - 8 parts of natural composite gum, 2 - 4 parts of calcium carbonate, and 3 - 6 parts of zeolite powder; The preparation method of the said modified activated carbon comprises the following steps: Step S1: Add activated carbon into concentrated nitric acid, stir and mix for 2 - 4 h, then filter, wash, and dry to obtain pretreated activated carbon; Step S2: Add the pretreated activated carbon and polyaspartic acid into N,N - dimethylformamide, mix evenly, ultrasonically vibrate for 10 - 30 min, then add 3 - hydroxypropylsulfonic acid, dicyclohexylcarbodiimide, and 4 - dimethylaminopyridine into it, start stirring, control the stirring rate at 500 - 650 r / min, stir for 4 - 6 h, then separate the product, wash, and dry to obtain modified activated carbon; The preparation method of the said mineral additive component comprises the following steps: Step T1: Disperse tourmaline powder into dimethyl sulfoxide to form a uniform dispersion liquid, add mercaptosuccinic acid and a catalyst, stir and mix evenly, then raise the temperature to 90 - 95 °C, react for 3 - 5 h, then filter by suction, wash, and dry to obtain modified tourmaline powder; Step T2: Add the modified tourmaline powder into N,N - dimethylformamide, disperse evenly, then add an aminopyridine compound, dicyclohexylcarbodiimide, and 4 - dimethylaminopyridine, react for 3 - 5 h, then discharge, wash, and dry to obtain the mineral additive component; The said aminopyridine compound is any one of 2 - aminopyridine, 3 - aminopyridine, or 4 - aminopyridine; The preparation method of the said natural composite gum is as follows: Add agar and arabinoxylan into deionized water, raise the temperature to 60 - 70 °C, stir and mix for 0.5 - 1 h, then add sodium tripolyphosphate, continue to stir for 2 - 4 h, wait until it cools to room temperature, then discharge to obtain the natural composite gum.

2. The activated carbon material for adsorbing heavy metals in soil according to claim 1, characterized in that, In step S1, the mass fraction of the said concentrated nitric acid is 60 - 65%.

3. The activated carbon material for adsorbing heavy metals in soil according to claim 1, characterized in that, In step S2, the ultrasonic frequency during the said ultrasonic vibration is 60 - 80 kHz.

4. The activated carbon material for adsorbing heavy metals in soil according to claim 1, characterized in that, In step T1, the said catalyst is p - toluenesulfonic acid or calcium methylsulfonate.

5. A manufacturing process of an activated carbon material for adsorbing heavy metals in soil as described in claim 1, characterized in that, It comprises the following steps: Step one: Add the modified activated carbon, mineral additive component, calcium carbonate, and zeolite powder into a blender, stir and mix for 10 - 30 min, then add the natural composite gum, keep the stirring rate unchanged, and continue to stir for 1 - 3 h to obtain a mixed base material; Step two: Put the mixed base material into a mold, extrude it into shape, then place it in a drying oven, dry at a temperature of 70 - 90 °C for 4 - 6 h, and then cool to room temperature to obtain the activated carbon material.

6. The manufacturing process of an activated carbon material for adsorbing heavy metals in soil according to claim 5, characterized in that, In step one, the said stirring rate is 150 - 300 r / min.

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