Chinese ilex branch and leaf based biochar material as well as preparation method and application thereof

Abstract

The invention provides a holly branch and leaf based biochar material as well as a preparation method and application thereof, and belongs to the technical field of adsorption materials. The preparation method comprises the following steps: by taking Chinese ilex branches and leaves rich in cellulose, hemicellulose, lignin and other biomass components as a carbon source, firstly carrying out dipping treatment on the Chinese ilex branches and leaves, then carrying out carbonization activation, and then carrying out acid leaching to form Chinese ilex branch and leaf biochar; the pore structure and surface chemical properties of the biochar can be further optimized, the prepared biochar material has a developed pore structure, a large specific surface area and abundant surface functional groups, and the toluene adsorption capacity of the biochar material can be remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adsorption materials, in particular to a Ilex branch leaf-based biochar material and a preparation method and application thereof. BACKGROUND

[0002] Toluene, as an important volatile organic compound (VOCs), is widely used in the fields of coatings, inks, adhesives, chemical synthesis, etc. It is a key raw material for paint thinner, rubber solvent and many fine chemical production. However, during the production, storage, transportation and use of toluene, a large amount of toluene enters the atmosphere, soil and water environment through volatilization, leakage and other ways. Toluene has strong volatility and toxicity. Inhaling high-concentration toluene vapor can cause acute poisoning to the central nervous system of human body, causing symptoms such as headache, dizziness, nausea and vomiting. Long-term exposure may cause damage to the hematopoietic system, abnormal liver and kidney function, and even potential carcinogenic risk. At the same time, toluene participates in photochemical reactions in the atmosphere, is an important precursor of ozone and secondary organic aerosols, seriously affects air quality, aggravates air pollution problems such as haze, and poses a double threat to the ecological system and human health.

[0003] At present, the treatment technologies for toluene pollutants in the environment mainly include adsorption method, catalytic combustion method, biological treatment method and photocatalytic oxidation method, etc. The adsorption method has become one of the most widely used technologies due to its advantages of flexible operation, high treatment efficiency and realization of pollutant enrichment and recovery. Traditional adsorption materials such as activated carbon have certain adsorption capacity for toluene, but have limited adsorption capacity, poor selectivity, easy desorption at high temperature, high regeneration energy consumption and easy secondary pollution. The adsorption selectivity and efficiency of molecular sieve and other materials for toluene need to be improved, and the preparation cost is high. Emerging adsorption materials such as graphene-based composite materials and metal-organic framework (MOFs) materials have improved toluene adsorption performance, but the synthesis process is complex, the stability is insufficient, and it is difficult to be applied in large scale for actual pollution control. Therefore, it is urgent to develop a low-cost, efficient, renewable and environmentally friendly adsorption material to effectively remove toluene pollutants. SUMMARY

[0004] The purpose of the present application is to provide a Ilex branch leaf-based biochar material and a preparation method and application thereof, which can realize efficient removal of toluene, and the material is low-cost, efficient, renewable and environmentally friendly.

[0005] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0006] The present application provides a preparation method of a Ilex branch leaf-based biochar material, comprising the following steps:

[0007] Mixing the branch and leaf of ilex with water, carrying out impregnation treatment, and then drying and crushing in sequence to obtain the dry powder of branch and leaf of ilex;

[0008] Carrying out carbonization treatment on the dry powder of branch and leaf of ilex to obtain the biochar matrix of branch and leaf of ilex;

[0009] Carrying out acid treatment on the biochar matrix of branch and leaf of ilex in acid liquor to obtain the biochar material based on branch and leaf of ilex.

[0010] Preferably, the temperature of the impregnation treatment is room temperature, and the time is 1h.

[0011] Preferably, after crushing, the obtained material is passed through an 80-mesh sieve to obtain the dry powder of branch and leaf of ilex.

[0012] Preferably, the carbonization treatment is carried out in a nitrogen atmosphere; the nitrogen gas is introduced at a rate of 300mL / min.

[0013] Preferably, the temperature of the carbonization treatment is 500℃, the time is 120min, and the temperature is raised to the temperature of the carbonization treatment at a rate of 10℃ / min.

[0014] Preferably, the acid in the acid liquor includes hydrochloric acid; the concentration of the acid liquor is 0.1mol / L, the use amount ratio of the biochar matrix of branch and leaf of ilex to the acid liquor is 1g:100mL, the temperature of the acid treatment is room temperature, and the time is 24h.

[0015] Preferably, after the acid treatment, the obtained product is sequentially subjected to suction filtration, drying and sieving to obtain the biochar material based on branch and leaf of ilex.

[0016] The application provides the biochar material based on branch and leaf of ilex prepared by the preparation method.

[0017] The application provides application of the biochar material based on branch and leaf of ilex in the field of adsorbing toluene.

[0018] The application provides a preparation method of a wintergreen branch leaf-based biochar material, which takes wintergreen branch leaves rich in biomass components such as cellulose, hemicellulose and lignin as a carbon source, and first performs immersion treatment on the wintergreen branch leaves, improves the properties of raw materials through physical and chemical actions, creates favorable conditions for subsequent pyrolysis carbonization, removes soluble impurities to improve the purity of the material, softens the biomass structure to promote pore development during pyrolysis, changes the structure of the adsorption material to improve the adsorption performance, and then performs carbonization and activation, and then forms wintergreen branch leaf biochar through acid immersion, and through modification by regulating the pyrolysis process parameters and combining with acid immersion, the acid immersion can efficiently remove inorganic ash, dredge blocked pores and increase effective adsorption space, slightly etch the carbon skeleton to optimize the pore structure and match the size of toluene molecules, regulate the surface chemical properties to enhance the hydrophobicity to match the non-polarity of toluene, avoid introducing interfering functional groups to ensure the adsorption stability, and improve the surface electrical neutrality to reduce the polarity repulsion, so that the adsorption capacity of the material for toluene can be significantly improved.

[0019] The application takes wintergreen branch leaves as raw materials to prepare biochar, and applies the biochar to the adsorption and removal of toluene pollutants, which can not only convert wintergreen branch leaves into high-value-added materials, solve the problem of wintergreen branch leaf waste disposal, realize the recycling of resources, but also provide an innovative solution for toluene pollution control, and has important theoretical significance and application value for promoting the coordinated development of environmental pollution control and biomass resource utilization. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a preparation process schematic diagram of the wintergreen branch leaf-based biochar material of the application;

[0021] Figure 2 It is a micro-morphology diagram of the wintergreen branch leaf-based biochar material prepared in Example 1 at 50 μm;

[0022] Figure 3 It is a micro-morphology diagram of the wintergreen branch leaf-based biochar material prepared in Example 1 at 5 μm;

[0023] Figure 4 It is an XRD diagram of the wintergreen branch leaf-based biochar material prepared in Example 1;

[0024] Figure 5 It is an XPS spectrum diagram of the wintergreen branch leaf-based biochar material prepared in Example 1, wherein a is an XPS full spectrum diagram, and b is a peak fitting diagram;

[0025] Figure 6 It is the adsorption effect of toluene of the wintergreen branch leaf-based biochar material prepared in Example 1 and the adsorption materials in Comparative Examples 1-4. DETAILED DESCRIPTION

[0026] In the present application, the required preparation raw materials or reagents are all commercially available goods well known to those skilled in the art unless otherwise specified.

[0027] As shown in Figure 1 The present application provides a preparation method of a wintergreen branch leaf based biochar material, comprising the following steps:

[0028] The wintergreen branch leaves are mixed with water, and after immersion treatment, drying and crushing are sequentially performed to obtain wintergreen branch leaf dry powder;

[0029] The wintergreen branch leaf dry powder is subjected to carbonization treatment to obtain a wintergreen branch leaf biochar matrix;

[0030] The wintergreen branch leaf biochar matrix is subjected to acid treatment in acid liquor to obtain a wintergreen branch leaf based biochar material.

[0031] The present application does not have special limitations on the source of the wintergreen branch leaves, which can be obtained in a conventional manner.

[0032] The present application preferably takes the branch leaf part of the wintergreen tree which is more than 0.5 meters above the ground and does not bloom in October.

[0033] The present application does not have special limitations on the amount of water used for mixing with the wintergreen branch leaves, which can be ensured to completely submerge the wintergreen branch leaves; the temperature of the immersion treatment is preferably room temperature, and the time is preferably 1 hour.

[0034] After the immersion treatment, the present application preferably repeatedly brushes the wintergreen branch leaves for 3 times until no soil and other impurities are left on the surface, and then the wintergreen branch leaves are fished out and drained.

[0035] The present application preferably cuts the wintergreen branch leaves after the immersion treatment to a size of 2-3 cm, and dries them at 60℃ for 24 hours; the dried wintergreen branch leaves are placed in a pulverizer, crushed for 3-4 minutes, collected, and then passed through an 80-mesh sieve (pore size is 0.2 mm) to obtain wintergreen branch leaf dry powder, which is sealed and dried for storage in a sample bag.

[0036] The present application preferably introduces high-purity nitrogen gas into a tube furnace for 10 minutes, discharges the gas in the tube, and then places a square crucible containing the wintergreen branch leaf dry powder into the tube furnace, and continues to introduce nitrogen gas for carbonization treatment.

[0037] In the present application, the carbonization treatment is preferably performed in a nitrogen atmosphere; the introduction rate of the nitrogen gas is preferably 300 mL / min.

[0038] In the present application, the temperature of the carbonization treatment is preferably 500℃, and the time is preferably 120 minutes; the temperature rising rate for rising to the temperature of the carbonization treatment is preferably 10℃ / min.

[0039] After the carbonization treatment is completed, the product is preferably naturally cooled, and then sieved through an 80-mesh screen (pore size 0.2 mm) to obtain the ilex branch leaf biochar substrate.

[0040] In the present application, the acid in the acid solution preferably includes hydrochloric acid; the concentration of the acid solution is preferably 0.1 mol / L; the use amount ratio of the ilex branch leaf biochar substrate to the acid solution is preferably 1 g:100 mL; and the temperature of the acid treatment is preferably room temperature, and the time is preferably 24 h.

[0041] In the present application, after the acid treatment, the obtained product is preferably sequentially subjected to suction filtration, drying, and sieving to obtain the ilex branch leaf-based biochar material.

[0042] The present application preferably uses a circulating water type multi-purpose vacuum pump and a suction filtration bottle, uses a qualitative filter paper with a medium speed for suction filtration, and then is dried at 60 DEG C for 3 h, and sieved through an 80-mesh screen to obtain the ilex branch leaf-based biochar material.

[0043] The present application provides the ilex branch leaf-based biochar material prepared by the preparation method described in the above technical solution.

[0044] The present application provides the application of the ilex branch leaf-based biochar material described in the above technical solution in the field of adsorbing toluene.

[0045] The present application does not have special limitations on the method of the application, and the application can be performed according to the methods well known in the art.

[0046] The present application does not have special limitations on the use amount ratio of the ilex branch leaf-based biochar material to toluene, and the use amount ratio can be adjusted according to actual needs.

[0047] The specific embodiments of the present application are described in detail below, but it should be understood that the protection scope of the present application is not limited by the specific embodiments. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present application. The experimental methods described in the embodiments of the present application are conventional methods, unless otherwise specified.

[0048] The experimental methods and detection methods described below are conventional methods, unless otherwise specified; and the reagents and raw materials described below are commercially available, unless otherwise specified.

[0049] Example 1

[0050] Step 1: Biomass raw material: the ilex branch leaf biochar substrate is prepared by using the ilex branch leaf part of 0.5 m above the ground of the unflowering ilex tree with a height of 2.5 m, which is not modified, and a pair of scissors.

[0051] Step 2, cleaning: 100g of ilex leaves were soaked in 500mL of deionized water at room temperature for 1h, and then repeatedly washed for 3 times until no dirt and other impurities were left on the surface, and then taken out and drained.

[0052] Step 3, drying: the ilex branches and leaves were cut to 2-3cm with scissors, placed in a tray, and then placed in an oven for drying at 60℃ for 24h.

[0053] Step 4, crushing: the dried ilex branch and leaf samples were placed in a crusher and crushed for 3min, then collected and sieved through an 80 mesh sieve (0.2mm aperture), and the powder was collected and sealed in a sample bag for dry storage.

[0054] Step 5, carbonization: 15g of ilex branch and leaf dry powder obtained in step 4 was weighed with a hundredth electronic balance, and placed in a square crucible. The weight of the square crucible containing the ilex branch and leaf dry powder was recorded before carbonization. The tube furnace was connected to a high-purity nitrogen gas at a flow rate of 300mL / min for 10min. The square crucible containing the ilex branch and leaf dry powder was placed in the tube furnace, and the nitrogen gas was continued to be introduced at a rate of 300mL / min. The temperature rising speed was set to 10℃ / min, and the carbonization was carried out at 500℃ for 120min. After natural cooling, the square crucible was taken out and weighed, and the weight was recorded. The biochar in the square crucible was sieved through an 80 mesh sieve (0.2mm aperture) to obtain ilex branch and leaf biochar substrate, which was collected and sealed in a sample bag for dry storage.

[0055] Step 6, 1g of ilex branch and leaf biochar substrate was accurately weighed and placed in a beaker, 100mL of 0.1mol / L HCl solution was added, and it was magnetically stirred at room temperature for 24h. Then a circulating water type multi-purpose vacuum pump and a filter bottle were used to perform suction filtration using a qualitative filter paper with a medium speed specification. The resulting product was dried at 60℃ for 3h, sieved through an 80 mesh sieve, and ilex branch and leaf based biochar material was obtained.

[0056] Comparative Example 1

[0057] Step 1: biomass raw material: the ilex tree in October was selected, with a height of 2.5m, and the ilex tree was not modified. The unflowering branch and leaf part above 0.5m from the ground was taken by scissors.

[0058] Step 2, cleaning: 100g of ilex branch and leaf was soaked in 500mL of deionized water at room temperature for 1h, and then repeatedly washed for 3 times until no dirt and other impurities were left on the surface, and then taken out and drained.

[0059] Step 3, drying: the ilex branches and leaves were cut to 2-3cm with scissors, placed in a tray, and then placed in an oven for drying at 60℃ for 24h.

[0060] Step four, crushing: the dried Ilex leaves sample was placed in a crusher, crushed for 3 min, collected and passed through an 80-mesh sieve (pore size 0.2 mm), and finally the powder was collected to obtain Ilex leaf dry powder, which was sealed and stored in a sample bag.

[0061] Step five, carbonization: 15 g of Ilex leaf dry powder obtained in step four was weighed with a ten-millionth electronic balance, loaded into a square crucible, and the entire square crucible loaded with Ilex leaf dry powder was weighed, and the weight before carbonization was recorded. The tube furnace was connected to a high-purity nitrogen gas at a flow rate of 300 mL / min for 10 min to exhaust the gas in the tube. The square crucible loaded with Ilex leaf dry powder was placed in the tube furnace, and nitrogen gas at a rate of 300 mL / min was continued for 120 min. The temperature rise rate was set to 10°C / min, and carbonization was carried out at 700°C for 120 min. After natural cooling, the square crucible was taken out and weighed, and the weight was recorded. The biochar in the square crucible after carbonization was taken out and passed through an 80-mesh sieve (pore size 0.2 mm) to obtain the adsorbent material.

[0062] Comparative Example 2

[0063] Step one, biomass raw material: Ilex trees in October, height 2.5 meters, unmodified Ilex trees, using scissors to take the flowerless branches and leaves above 0.5 m from the ground.

[0064] Step two, cleaning: 100 g of Ilex branches and leaves were soaked in 500 mL of deionized water at room temperature for 1 hour, and then washed repeatedly for 3 times until no dirt and other impurities were left on the surface. The Ilex branches and leaves were taken out and drained.

[0065] Step three, drying: the Ilex branches and leaves were cut to 2-3 cm with scissors, placed in a tray, and then placed in an oven for drying at 60°C for 24 h.

[0066] Step four, crushing: the dried Ilex leaves sample was placed in a crusher, crushed for 3 min, collected and passed through an 80-mesh sieve (pore size 0.2 mm), and finally the powder was collected to obtain Ilex leaf dry powder, which was sealed and stored in a sample bag.

[0067] Step five, carbonization: 15 g of dry powder of Ilex leaves obtained in step four was weighed with an electronic balance of 100,000th, and was loaded into a square crucible. The square crucible loaded with dry powder of Ilex leaves was weighed as a whole, and the weight before carbonization was recorded. The tubular furnace was connected to high-purity nitrogen gas at a flow rate of 300 mL / min for 10 min to exhaust the gas in the tube. The square crucible loaded with dry powder of Ilex leaves was placed in the tubular furnace, and nitrogen gas at a flow rate of 300 mL / min was continuously introduced for 120 min. The temperature was set to increase at a rate of 10°C / min, and carbonization was carried out at 600°C for 120 min. After natural cooling, the square crucible was taken out and weighed, and the weight was recorded. The biochar in the square crucible after carbonization was taken out and sieved through an 80-mesh sieve (pore size 0.2 mm) to obtain the adsorbent material.

[0068] Comparative Example 3

[0069] Step one, biomass raw material: Ilex trees in October, height 2.5 meters, unmodified Ilex trees, using scissors to take the flowerless branch and leaf part above 0.5 m from the ground.

[0070] Step two, cleaning: 100 g of Ilex branches and leaves were soaked in 500 mL of deionized water at room temperature for 1 hour, and then repeatedly washed for 3 times until no dirt and other impurities were left on the surface. After washing, the Ilex branches and leaves were taken out and drained.

[0071] Step three, drying: the Ilex branches and leaves were cut to 2-3 cm with scissors, placed in a tray, and then placed in an oven for drying at 60°C for 24 h.

[0072] Step four, crushing: the dried Ilex branch and leaf sample was placed in a crusher and crushed for 3 min. After collection, the sample was sieved through an 80-mesh sieve (pore size 0.2 mm). Finally, the powder was collected, and the dry powder of Ilex branches and leaves was obtained. The sample was sealed in a sample bag and stored dry.

[0073] Step five, carbonization: 15 g of dry powder of Ilex leaves obtained in step four was weighed with an electronic balance of 100,000th, and was loaded into a square crucible. The square crucible loaded with dry powder of Ilex leaves was weighed as a whole, and the weight before carbonization was recorded. The tubular furnace was connected to high-purity nitrogen gas at a flow rate of 300 mL / min for 10 min to exhaust the gas in the tube. The square crucible loaded with dry powder of Ilex leaves was placed in the tubular furnace, and nitrogen gas at a flow rate of 300 mL / min was continuously introduced for 120 min. The temperature was set to increase at a rate of 10°C / min, and carbonization was carried out at 600°C for 120 min. After natural cooling, the square crucible was taken out and weighed, and the weight was recorded. The biochar in the square crucible after carbonization was taken out and sieved through an 80-mesh sieve (pore size 0.2 mm) to obtain the adsorbent material.

[0074] Comparative Example 4

[0075] Step one: Biomass raw material: Select the holly tree in October, height 2.5 meters, unmodified holly tree, use scissors to take the flowerless branch and leaf part above 0.5m from the ground.

[0076] Step two, cleaning: soak 100g of holly branches and leaves in 500mL of deionized water at room temperature for 1 hour, then brush repeatedly for 3 times until there is no dirt and other impurities on the surface, then take out and drain.

[0077] Step three, drying: cut the holly branches and leaves to 2-3cm with scissors, put them into a tray, and then put them into an oven for drying at 60℃ for 24h.

[0078] Step four, crushing: put the dried holly branch and leaf samples into a crusher and crush them for 3min, then collect them and pass them through an 80-mesh sieve (pore size 0.2mm), finally collect the powder and seal it in a sample bag for dry storage.

[0079] Step five, carbonization: weigh 15g of the holly branch and leaf dry powder obtained in step four with a ten-millionth electronic balance, put it into a square crucible, weigh the whole square crucible containing the holly branch and leaf dry powder, and record the weight before carbonization. Introduce 300mL / min of high-purity nitrogen into the tube furnace for 10min to exhaust the gas in the tube. Put the square crucible containing the holly branch and leaf dry powder into the tube furnace and continue to introduce nitrogen at a rate of 300mL / min for 120min. Set the heating rate to 10℃ / min, carbonize at 500℃ for 120min, and take out the square crucible after natural cooling. Weigh and record the weight, and take out the biochar in the square crucible after carbonization and pass it through an 80-mesh sieve (pore size 0.2mm) to obtain the adsorbent material.

[0080] Step six, alkali modification: take 1g of the above adsorbent material and put it into a baking pan, add 100mL of 0.1 mol / L KOH solution, and stir magnetically at room temperature for 24h. Then use a circulating water type multi-purpose vacuum pump and a filter bottle, use a qualitative filter paper with a medium speed specification, and dry most of the water. Put the filter membrane and biochar powder together in a drying oven and dry at 60℃ for 3h, pass through an 80-mesh sieve, and put it into a sealed bag for storage.

[0081] Characterization and performance test

[0082] 1) Figure 2 Micro-morphology graph of holly branch and leaf based biochar material prepared in Example 1 at 50μm; Figure 3 Micro-morphology graph of holly branch and leaf based biochar material prepared in Example 1 at 5μm; Figures 2-3It can be seen that the morphology change caused by acid modification is due to the etching effect of HCl on the surface of activated carbon. The originally flat surface becomes rough, the original occupied pore is exposed, but part of it may collapse, and the external surface area increases.

[0083] 2) Figure 4 XRD pattern of the biochar material prepared from the Ilex branch and leaf in Example 1; a is the full spectrum, b is the peak fitting diagram; by Figure 4 It can be seen that the characteristic diffraction peak appears at 12.25°, which corresponds to the amorphous carbon / organic mineral composite phase structure. During high-temperature pyrolysis, the lignocellulose in the Ilex branch and leaf is converted into highly amorphous carbon structure. The diffraction peak appears at 26.5°, which corresponds to the 101 crystal plane of SiO2. The characteristic diffraction peak appears at 29.44°, which corresponds to the 104 crystal plane of CaCO3 detected in the biochar. The characteristic diffraction peak appears at 43.2°, which corresponds to the (100) crystal plane of graphitization, reflecting the local graphitization of the carbon material.

[0084] 3) Figure 5 XPS spectrum of the biochar material prepared from the Ilex branch and leaf in Example 1, wherein a is the XPS full spectrum and b is the peak fitting diagram; by Figure 5 It can be seen that the graphite carbon peak is enhanced: HCl treatment may remove ash (such as CaCO3, silicate), reduce impurities shielding the carbon signal, and make the C=C peak more prominent. The oxygen-containing peak is weakened: acidic conditions may protonate or hydrolyze part of the unstable oxygen-containing groups (such as esters), resulting in a decrease in the C-O / C=O ratio. Surface properties: acid modification improves the carbon purity and enhances the hydrophobicity, but may reduce the acidic functional groups (such as -COOH), affecting the adsorption capacity of pollutants.

[0085] Test example

[0086] The biochar material prepared from the Ilex branch and leaf in Example 1 and the materials prepared in Comparative Examples 1-4 were used for adsorbing toluene, and the specific steps were as follows:

[0087] (1) Before the experiment, the pipeline was purged with nitrogen for 20 min to remove impurity gases in the pipeline.

[0088] (2) Set the temperature of the water bath to 20℃, add 1500mL of deionized water, and place the washing bottle in the water bath, and add 200mL of deionized water as the gas volatilization device of toluene.

[0089] (3) Weigh 1g of biochar material and transfer it to the adsorption tube with weighing paper. The adsorption tube is fixed with cotton on both sides, and finally the ends of the adsorption tube are tightened.

[0090] (4) The toluene tail gas is absorbed with ethanol.

[0091] (5) After the temperature of the water bath reaches, set the flow meter to 500 mL / min, use a pipette to suck 0.1 mL of toluene liquid, and inject it into the washing bottle, wait for 15 min after the pipeline continues to ventilate, start collecting the inlet and outlet concentrations of the initial toluene, and then sample every 10 min, 10 min, 10 min, 15 min, 15 min, 30 min, 30 min, respectively, take the inlet and outlet toluene gas, and take 7 samples.

[0092] (6) 10 min after the sampling is completed, close the flow meter, open the adsorption tube to take out the adsorbent. Pour the liquid in the washing bottle into the waste liquid tank for cleaning. After a new washing bottle is selected and 200 mL of deionized water is added, connect it again, put it into the water bath again, and continue to blow for 30 min to prevent toluene gas residues.

[0093] (7) Use a portable gas chromatography-mass spectrometer to determine the concentration of toluene gas.

[0094] Figure 6 The adsorption effect of the Ilex branch leaf-based biochar material prepared in Example 1 and the adsorption materials in Comparative Examples 1-4 on toluene is determined. Figure 6 It can be known that the maximum adsorption capacity of the Ilex branch leaf-based biochar material obtained by the method is 30.71 mg / g.

[0095] The above is only the preferred embodiment of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing holly twig-based biochar material, characterized in that, Includes the following steps: Holly branches and leaves are mixed with water and soaked, then dried and pulverized in sequence to obtain holly branch and leaf powder. The dried powder of holly branches and leaves was carbonized to obtain holly branch and leaf biochar matrix. The holly tree branch and leaf biochar matrix was subjected to acid treatment in an acidic solution to obtain holly tree branch and leaf based biochar material.

2. The preparation method according to claim 1, characterized in that, The immersion treatment was performed at room temperature for 1 hour.

3. The preparation method according to claim 1, characterized in that, After crushing, the resulting material is passed through an 80-mesh sieve to obtain dry powder of holly branches and leaves.

4. The preparation method according to claim 1, characterized in that, The carbonization process is carried out in a nitrogen atmosphere; the nitrogen flow rate is 300 mL / min.

5. The preparation method according to claim 1 or 4, characterized in that, The carbonization treatment is performed at a temperature of 500°C for 120 minutes; the heating rate to the carbonization treatment temperature is 10°C / min.

6. The preparation method according to claim 1, characterized in that, The acid in the acid solution includes hydrochloric acid; the concentration of the acid solution is 0.1 mol / L; the ratio of the holly tree branch and leaf biochar matrix to the acid solution is 1 g: 100 mL; the acid treatment temperature is room temperature and the time is 24 h.

7. The preparation method according to claim 1 or 6, characterized in that, After acid treatment, the product obtained in this invention is sequentially filtered, dried and sieved to obtain holly tree branch and leaf-based biochar material.

8. The holly branch-based biochar material prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the holly tree branch and leaf-based biochar material according to claim 8 in the field of toluene adsorption.

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