Ultrahigh-temperature municipal sludge-based biochar material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of municipal sludge treatment, provides an ultrahigh-temperature municipal sludge-based biochar material as well as a preparation method and application thereof, and solves the problem of low utilization value of municipal sludge. The method comprises the following steps: mixing municipal sludge, a carbon source and water to obtain a precursor; and carbonizing the precursor, and introducing water vapor for activation to obtain the ultrahigh-temperature municipal sludge-based biochar material. The carbon material provided by the invention is subjected to ultrahigh-temperature carbonization, so that the mechanical property of the material is remarkably improved; and water vapor is introduced after carbonization is finished, so that steam holes are effectively formed in the surface of the material, the integrity of the structure and the morphology is kept, the specific surface area of the material is greatly increased, and the performance of the material is improved. The method provided by the invention is simple, efficient, wide in raw material source and low in cost; the process requirement is low, the municipal sludge treatment and disposal effect is improved, and the resource application path of municipal sludge treatment and disposal products is broadened.

Description

Technical Field

[0001] The present invention relates to the technical field of municipal sludge treatment, and in particular to an ultra-high temperature municipal sludge-based biochar material and a preparation method and application thereof. Background Art

[0002] At present, the more mature municipal sludge carbonization systems are medium-low temperature and medium-high temperature carbonization systems. The equipment mainly consists of a feeding system, a drying system, a pyrolysis carbonization furnace, a cooling system, a gas treatment system and a control system. Specifically, the feeding system is used to feed the municipal sludge into the carbonization equipment. The feeding system usually includes a municipal sludge storage tank, a feed pump and a conveying pipeline. Drying system: Municipal sludge needs to be dried before entering the carbonization furnace to reduce its moisture content. The drying system may include a heat exchanger, a drying chamber, etc. Pyrolysis carbonization furnace: This is the core part of the municipal sludge carbonization equipment. In the carbonization furnace, municipal sludge is heated to a high temperature under anaerobic or anoxic conditions and decomposed into gas, liquid and solid products. Cooling system: used to cool the solid product (biochar) produced by pyrolysis carbonization to a safe temperature. Gas treatment system: including a gas purification device, which is used to treat and purify the gas produced during the pyrolysis process, such as removing harmful components. Control system: used to monitor and adjust the entire carbonization process to ensure stable operation of the equipment. The material usually enters the drying system through the feeding system, and after drying and dehydration, it enters the pyrolysis carbonization furnace through a conveyor belt. The obtained carbonized product is transferred to the cooling system via a conveyor belt, and is output from the device after cooling to a certain temperature. The carbonization temperature used in the prior art is low-medium temperature carbonization, and the activation system is relatively independent of the municipal sludge carbonization system. Therefore, the specific surface area of ​​the obtained product is small, and it is generally used as a soil conditioner, which leads to a narrow resource path for the product and limited application areas. Therefore, improving the existing municipal sludge treatment process and increasing the application areas of municipal sludge have become the main research directions for the resource utilization of municipal sludge. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects in the prior art and provide an ultra-high temperature municipal sludge-based biochar material and a preparation method and application thereof.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing an ultra-high temperature municipal sludge-based biochar material, comprising the following steps:

[0006] (1) Mixing municipal sludge, a carbon source and water to obtain a precursor;

[0007] (2) After the precursor is carbonized, water vapor is introduced into the precursor for activation to obtain the ultra-high temperature municipal sludge-based biochar material.

[0008] Preferably, the particle size of the municipal sludge in step (1) is ≥40 mesh.

[0009] Preferably, in step (1), the mass volume ratio of municipal sludge, carbon source and water is 40-60 g: 15-30 g: 80-120 mL;

[0010] The carbon source is one or more of agricultural waste, livestock waste, urban organic waste and invasive plants.

[0011] Preferably, the mixing temperature in step (1) is 60-100° C. and the mixing time is 20-30 h.

[0012] Preferably, the heating rate of carbonization in step (2) is 3-10° C. / min, and the nitrogen flow rate is 80-150 mL / min.

[0013] Preferably, the target temperature of carbonization in step (2) is 1100-1200° C., and the holding time is 0.5-2 h.

[0014] Preferably, in step (2), the flow rate of water vapor is 80 to 500 mL / min, and the activation time is 30 to 90 min.

[0015] The present invention also provides an ultra-high temperature municipal sludge-based biochar material prepared by the method for preparing the ultra-high temperature municipal sludge-based biochar material.

[0016] The present invention also provides the use of the ultra-high temperature municipal sewage sludge-based biochar material in pollutant adsorption.

[0017] The present invention provides a method for preparing an ultra-high temperature municipal sludge-based biochar material, comprising the following steps: mixing municipal sludge, a carbon source and water to obtain a precursor; carbonizing the precursor and then introducing water vapor to activate it, thereby obtaining the ultra-high temperature municipal sludge-based biochar material. The ultra-high temperature municipal sludge-based biochar material provided by the present invention significantly improves the mechanical properties of the material after ultra-high temperature carbonization, which is convenient for subsequent processing; and after the carbonization is completed, water vapor is introduced to effectively form steam pores on the surface of the material while maintaining the integrity of the structure and morphology, greatly increasing the specific surface area of ​​the material, so that the performance of the material is improved.

[0018] The method provided by the present invention is simple and efficient, with a wide source of raw materials and low cost; the process requirements are low, and there is no need to make major changes to the existing system. Material production can be achieved by simply adding a steam generator; the municipal sludge treatment and disposal effect is improved, and the resource application path of municipal sludge treatment and disposal products is widely used. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1This is a scanning electron microscope image of the ultra-high temperature municipal sewage sludge-based biochar material prepared in Example 1;

[0020] Figure 2 This is a nitrogen adsorption-desorption curve diagram of the ultra-high temperature municipal sludge-based biochar material prepared in Example 1;

[0021] Figure 3 This is a pore size distribution diagram of the ultra-high temperature municipal sludge-based biochar material prepared in Example 1;

[0022] Figure 4 The X-ray powder diffraction pattern of the ultra-high temperature municipal sewage sludge-based biochar material prepared in Example 1;

[0023] Figure 5 A comparison chart of the saturated adsorption of tetracycline by the ultra-high temperature municipal sludge-based biochar material and the medium-high temperature municipal sludge biochar prepared in Example 1;

[0024] Figure 6 This is a scanning electron microscope image of the ultra-high temperature municipal sewage sludge-based biochar material prepared in Example 2;

[0025] Figure 7 This is a Fourier infrared spectrum of the ultra-high temperature municipal sewage sludge-based biochar material prepared in Example 2;

[0026] Figure 8 This is the X-ray diffraction pattern of the ultra-high temperature municipal sewage sludge-based biochar material prepared in Example 2;

[0027] Fig. 9 This is a diagram showing the effect of multiple cycles of adsorption and removal of tetracycline by the ultra-high temperature municipal sludge-based biochar material and the high temperature municipal sludge-based biochar material prepared in Example 2;

[0028] Fig.10 This is a scanning electron microscope image of the ultra-high temperature municipal sludge-based biochar material prepared in Example 3;

[0029] Fig.11 The nitrogen adsorption-desorption curves of the ultra-high temperature municipal sludge-based biochar material and the high temperature municipal sludge-based biochar material prepared in Example 3;

[0030] Fig.12 This is a Fourier infrared spectrum of the ultra-high temperature municipal sewage sludge-based biochar material prepared in Example 3;

[0031] Fig.13 This is a diagram showing the multiple-cycle adsorption and removal effect of tetracycline by the ultra-high temperature municipal sludge-based biochar material and the high temperature municipal sludge-based biochar material prepared in Example 3. DETAILED DESCRIPTION

[0032] The present invention provides a method for preparing an ultra-high temperature municipal sludge-based biochar material, comprising the following steps:

[0033] (1) Mixing municipal sludge, a carbon source and water to obtain a precursor;

[0034] (2) After the precursor is carbonized, water vapor is introduced into the precursor for activation to obtain the ultra-high temperature municipal sludge-based biochar material.

[0035] In the present invention, the municipal sludge is first dried, and the drying temperature is preferably 100-110°C, more preferably 102-108°C, and more preferably 104-106°C; the drying time is preferably ≥24h, more preferably ≥26h, and more preferably ≥30h.

[0036] In the present invention, the municipal sludge is crushed after drying. The particle size of the municipal sludge in step (1) is preferably ≥40 mesh, more preferably ≥60 mesh, and even more preferably ≥100 mesh.

[0037] In the present invention, the mass volume ratio of municipal sludge, carbon source and water in step (1) is preferably 40-60g:15-30g:80-120mL, further preferably 45-55g:22-28g:85-115mL, and more preferably 48-52g:24-26g:90-110mL.

[0038] In the present invention, the carbon source is one or more of agricultural waste, animal husbandry waste, urban organic waste and invasive plants.

[0039] In the present invention, agricultural waste includes straw, shells, corn cobs and wood chips; animal husbandry waste includes chicken manure, cow manure and pig manure; urban organic waste includes food waste; and invasive plants include golden rod grass.

[0040] In the present invention, municipal sludge, carbon source and water are stirred evenly before the next step of mixing.

[0041] In the present invention, the mixing temperature in step (1) is preferably 60-100°C, more preferably 65-95°C, more preferably 70-90°C; the mixing time is preferably 20-30h, more preferably 22-28h, more preferably 24-26h.

[0042] In the present invention, carbonization is carried out in a nitrogen atmosphere; the heating rate of carbonization in step (2) is preferably 3 to 10°C / min, more preferably 4 to 7°C / min, and more preferably 5 to 6°C / min; the nitrogen flow rate is preferably 80 to 150 mL / min, more preferably 90 to 110 mL / min, and more preferably 95 to 105 mL / min.

[0043] In the present invention, the target temperature of carbonization in step (2) is preferably 1100-1200°C, more preferably 1120-1180°C, and more preferably 1140-1160°C; the holding time is preferably 0.5-2h, more preferably 0.6-1.4h, and more preferably 0.8-1.2h.

[0044] In the present invention, after the carbonization heat preservation time is over, the water vapor generator is turned on to introduce water vapor while keeping the temperature unchanged.

[0045] In the present invention, the flow rate of water vapor in step (2) is preferably 80 to 500 mL / min, more preferably 100 to 400 mL / min, and more preferably 200 to 300 mL / min; the activation time is preferably 30 to 90 min, more preferably 35 to 55 min, and more preferably 40 to 50 min.

[0046] In the present invention, after the activation is completed, the introduction of water vapor is stopped, and the material is naturally cooled to room temperature to obtain an ultra-high temperature municipal sludge-based biochar material.

[0047] The present invention also provides an ultra-high temperature municipal sludge-based biochar material prepared by the method for preparing the ultra-high temperature municipal sludge-based biochar material.

[0048] The present invention also provides the use of the ultra-high temperature municipal sewage sludge-based biochar material in pollutant adsorption.

[0049] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0050] Example 1

[0051] Place the municipal sludge in an electric blast drying oven and dry it at 105°C for 24 hours. The dried municipal sludge is crushed and sieved (40 mesh), and the sieved municipal sludge is retained for subsequent use. Mix 50g of sieved municipal sludge and 25g of wheat straw and add 100mL of deionized water, stirring continuously to fully mix the municipal sludge and straw. The mixture is transferred to an electric blast drying oven, and the product obtained after drying at 80°C for 24 hours is the precursor. The precursor is transferred to a clean porcelain boat and placed in a tube furnace. In a nitrogen atmosphere, the precursor is heated to 1150°C (heating rate: 5°C / min, nitrogen flow rate: 100mL / min) and maintained at this temperature for 1 hour. After that, the steam generator was turned on and connected to the tube furnace. The parameters of the steam generator were set as follows: the steam flow rate was 100 mL / min, the duration was 30 min, and the temperature of the tube furnace was 1150 ° C. Then the steam was stopped. The product obtained by natural cooling was the ultra-high temperature municipal sludge-based biochar material, recorded as WMBs.

[0052] The ultra-high temperature municipal sludge-based biochar material prepared in this example was observed under an electron microscope, and the scanning electron microscope image obtained was as follows: Figure 1 As shown. Figure 1 It can be seen that after ultra-high temperature carbonization and activation, the microstructure of the material is not damaged, and steam pores are introduced into the original structure (marked with red boxes in the figure), which is the main reason for the improvement of the material's adsorption performance.

[0053] The nitrogen adsorption-desorption curve of the ultra-high temperature municipal sludge-based biochar material prepared in this example is shown in Figure 2 As shown, from Figure 2 It can be seen that the nitrogen adsorption-desorption curve of the material belongs to a type IV isotherm, and there is an obvious H4 type hysteresis loop caused by capillary phenomenon, which is a classic feature of biochar materials.

[0054] The pore size distribution of the ultra-high temperature municipal sludge-based biochar material prepared in this example is shown in FIG. Figure 3 As shown, from Figure 3 It can be seen that the pore size distribution of the material is relatively wide, mainly mesopores of 2 to 50 nm. The presence of a large number of mesopores makes the material have certain adsorption properties and effects on organic dyes, antibiotics and heavy metals. The specific surface area of ​​the material is calculated to be 294.73 m 2 / g, much higher than the municipal sludge-based biochar (30-75m 2 / g).

[0055] The X-ray powder diffraction pattern of the ultra-high temperature municipal sludge-based biochar material prepared in this example is as follows: Figure 4 As shown, from Figure 4It can be seen that the characteristic peaks in the ultra-high temperature municipal sludge-based biochar materials belong to silicon dioxide, which comes from the silicon dioxide in the raw materials and the silicon oxides converted from silicon in the preparation process. The presence of silicon oxides effectively supports the pore structure of the material, and the pores do not collapse or break when the carbon atoms rearrange under ultra-high temperature conditions, thus giving the material excellent adsorption properties.

[0056] The comparison of the saturated adsorption of tetracycline by the ultra-high temperature municipal sludge-based biochar material and the medium-high temperature municipal sludge biochar prepared in this example is shown in the figure. Figure 5 As shown, from Figure 5 It can be seen that under the same tetracycline concentration and material dosage, the adsorption effect of ultra-high temperature municipal sludge-based biochar on tetracycline is much higher than that of medium-high temperature municipal sludge biochar. And the saturated adsorption capacity of ultra-high temperature municipal sludge-based biochar is about twice that of medium-high temperature municipal sludge biochar. The improvement in the adsorption effect of the material on tetracycline is mainly due to the rearrangement of carbon elements and the "pore-making" effect brought about by water vapor activation under ultra-high temperature environment. In addition, the silicon oxide compounds in the material can effectively improve the impact resistance of the activated carbide, so that the microstructure of the material remains stable.

[0057] Example 2

[0058] Place the municipal sludge in an electric blast drying oven and dry it at 105°C for 24 hours. The dried municipal sludge is crushed and sieved (40 mesh), and the sieved municipal sludge is retained for subsequent use. Mix 50g of sieved municipal sludge and 20g of crushed golden rod grass and add 120mL of deionized water, stirring continuously to fully mix the municipal sludge and golden rod grass. The mixture is transferred to an electric blast drying oven, and the product obtained after drying at 80°C for 24 hours is the precursor. The precursor is transferred to a clean porcelain boat and placed in a tube furnace. In a nitrogen atmosphere, the precursor is heated to 1200°C (heating rate: 10°C / min, nitrogen flow rate: 100mL / min) and maintained at this temperature for 2 hours. Afterwards, the steam generator was turned on and connected to the tube furnace. The parameters of the steam generator were set as follows: the steam flow rate was 100 mL / min, the duration was 60 min, and the temperature of the tube furnace was 1200 ° C. Then the steam was stopped. The product obtained by natural cooling was the ultra-high temperature municipal sludge-based biochar material.

[0059] The ultra-high temperature municipal sludge-based biochar material prepared in this example was observed under an electron microscope, and the scanning electron microscope image obtained was as follows: Figure 6 As shown. Figure 6It can be seen that the municipal sludge and the stems of golden rod grass are in full contact. Under the action of high temperature and activation, the pores of the plant stems and the pores of the municipal sludge are tightly combined and connected, which greatly improves the pore utilization rate of the two components.

[0060] The ultra-high temperature municipal sludge-based biochar material and the high temperature municipal sludge-based biochar material prepared in this example were tested for pore parameters, and the results are shown in Table 1. By comparison, it can be seen that the specific surface area of ​​the ultra-high temperature municipal sludge-based biochar is 3.78 times that of the material obtained at high temperature, the total pore volume of the former is 4.5 times that of the latter, and the pore size is also increased by 1.1 nm. It can be seen that the ultra-high temperature municipal sludge-based biochar has better adsorption properties after ultra-high temperature treatment.

[0061] Table 1 Pore parameters of ultra-high temperature municipal sludge-based biochar materials and high temperature municipal sludge-based biochar materials

[0062]

[0063] The Fourier infrared spectrum of the ultra-high temperature municipal sludge-based biochar material prepared in this example is shown in Figure 7 As shown in the figure, the main functional groups in the material include -OH (3431cm -1 )、CH(2015cm -1 )、CO(1038cm -1 ) and Si-O (400-800cm -1 The presence of -OH indicates that hydrogen bonding plays an important role in the adsorption process; CH mainly comes from the aromatic rings in biochar, which is the source of the chemical stability of the material at the atomic level; CO comes from the reaction between biochar and water vapor during the thermal decomposition and activation of oxygen-containing organic matter in the raw material, thereby generating new active sites and increasing the adsorption capacity of the material; Si-O is evolved from the Si element in the raw material, and its existence has a certain supporting effect on the microscopic pores of the material.

[0064] The X-ray diffraction pattern of the ultra-high temperature municipal sludge-based biochar material prepared in this example is as follows: Figure 8 As shown in the figure, the crystalline component of the biochar material is SiO2, which is consistent with the results of the Fourier infrared spectrum analysis. The volume integral appears at about 25°, indicating that the carbon in the material exists in an amorphous form, that is, the biochar material. In addition, no other impurity peaks appear, indicating that the ultra-high temperature carbonization and activation process has a stabilizing effect on the metal elements in the raw materials, which is conducive to the generation of more adsorption active sites. It also shows that biochar has the main adsorption function.

[0065] The results of the multiple cycles of adsorption and removal of tetracycline by the ultra-high temperature municipal sludge-based biochar material and the high temperature municipal sludge-based biochar material prepared in this example are shown in the figure. Fig. 9 As shown in the figure, after three adsorptions, the adsorption and removal rate of tetracycline by ultra-high temperature municipal sludge-based biochar materials decreased from 98.54±0.52% to 92.91±0.37%, while the adsorption of tetracycline by high temperature municipal sludge-based biochar materials decreased from 87.13±0.72% to 65.63±0.47%. By comparison, it was found that the initial removal rate of ultra-high temperature municipal sludge-based biochar materials was higher than that of high temperature municipal sludge-based biochar materials, which benefited from the interconnection between the stems of golden rod grass and the pores in the sludge. In the third adsorption and removal experiment, the removal efficiency of ultra-high temperature municipal sludge-based biochar materials was only reduced by about 0.05% compared with the initial state, while that of high temperature municipal sludge-based biochar materials was reduced by about 24.67%. This is because ultra-high temperature carbonization and activation promote the formation and exposure of more SiO2 sites, thereby increasing the material's resistance to thermal shock and the integrity of the pore structure.

[0066] Example 3

[0067] The municipal sludge was placed in an electric blast drying oven and dried at 105°C for 24 hours. The dried municipal sludge was crushed and sieved (40 mesh), and the sieved municipal sludge was retained for subsequent use. 60g of sieved municipal sludge and 15g of crushed food waste were mixed and 100mL of deionized water was added, and the municipal sludge and food waste were mixed continuously. The mixture was transferred to an electric blast drying oven, and the product obtained after drying at 80°C for 24 hours was the precursor. The precursor was transferred to a clean porcelain boat and placed in a tube furnace. In a nitrogen atmosphere, the precursor was heated to 1150°C (heating rate: 5°C / min, nitrogen flow rate: 150mL / min) and maintained at this temperature for 1.5 hours. Afterwards, the steam generator was turned on and connected to the tube furnace. The parameters of the steam generator were set as follows: the steam flow rate was 500 mL / min, the duration was 90 min, and the temperature of the tube furnace was 1150 ° C. Then the steam was stopped. The product obtained by natural cooling was the ultra-high temperature municipal sludge-based biochar material.

[0068] The ultra-high temperature municipal sludge-based biochar material prepared in this example was observed under an electron microscope, and the scanning electron microscope image obtained was as follows: Fig.10 As shown in the figure, it can be seen that the kitchen waste and sludge are fully mixed and carbonized to form a uniform whole. After activation, crack-like channels appear on the microscopic surface of the material, which is conducive to the maximum contact between the material and the pollutants during the adsorption process, thereby indirectly improving the adsorption and degradation rate of the material.

[0069] The nitrogen adsorption-desorption curves of the ultra-high temperature municipal sludge-based biochar material and the high temperature municipal sludge-based biochar material prepared in this example are shown in FIG. Fig.11 As shown in the figure, it can be seen that the hysteresis loop in the nitrogen adsorption-desorption curve of ultra-high temperature municipal sludge-based biochar is of H4 type, while that of high temperature municipal sludge-based biochar belongs to H3 type, indicating that the pores of ultra-high temperature municipal sludge-based biochar are slit-type pores, and the pores of high temperature municipal sludge-based biochar are ink bottle pore structures.

[0070] The ultra-high temperature municipal sludge-based biochar material and the high temperature municipal sludge-based biochar material prepared in this embodiment were tested for pore parameters, and the results are shown in Table 2. It can be seen that the specific surface area, total pore volume and pore diameter of the municipal sludge-based biochar material prepared in this embodiment are 5.57 times, 2.85 times and 1.99 times that of the high temperature municipal sludge-based biochar, respectively. By comparison, it can be seen that ultra-high temperature carbonization and steam activation can synergistically improve the pore structure of the material, thereby significantly improving the adsorption performance of the material.

[0071] Table 2 Pore parameters of ultra-high temperature municipal sludge-based biochar materials and high temperature municipal sludge-based biochar materials

[0072]

[0073] The Fourier infrared spectrum of the ultra-high temperature municipal sludge-based biochar material prepared in this example is shown in Fig.12 As shown in the figure, it can be seen that at 3637cm -1 The functional group at 3420cm is -NH, which mainly comes from the substances with high protein content in the kitchen. The -OH functional group is located at 3420cm -1 , hydrogen-bond related functional groups exist in the material, indicating that hydrogen bonding will play a vital role in the adsorption process of the material. 1408-2012cm -1 The functional groups at 1033cm are composed of C and H, mainly -CH2 and -CH3, which are typical biochar-related functional groups. -1 The presence of CO at 400-800cm proves the existence of a large number of active sites in the material, which is an important reason why the material exhibits excellent adsorption and removal performance. -1 The main functional group is Si-O. The presence of this functional group effectively improves the material's resistance to thermal shock and theoretically verifies the possibility of achieving regenerative adsorption through heat treatment.

[0074] The ultra-high temperature municipal sludge-based biochar material and the high temperature municipal sludge-based biochar material prepared in this example have multiple cycle adsorption and removal effects on tetracycline. Fig.13As shown in the figure, it can be seen that the initial adsorption removal rate of tetracycline by ultra-high temperature municipal sludge-based biochar material is 96.36±0.76%, while the initial adsorption removal rate of high temperature municipal sludge-based biochar material is 81.23±0.91%. The main reason for this difference comes from different pore structures, functional group compositions, etc. In the third cycle adsorption experiment, the adsorption removal rate of ultra-high temperature municipal sludge-based biochar can still be maintained above 90% (91.57±1.01%), while the adsorption removal rate of high temperature municipal sludge-based biochar is only 55.43±1.87%.

[0075] It can be seen from the above embodiments that the present invention provides a method for preparing an ultra-high temperature municipal sludge-based biochar material; the municipal sludge-based biochar material provided by the present invention, after ultra-high temperature carbonization, significantly improves the mechanical properties of the material, which is convenient for subsequent treatment; and after the carbonization is completed, water vapor is introduced to effectively form steam pores on the surface of the material while maintaining the integrity of the structure and morphology, greatly increasing the specific surface area of ​​the material, so that the performance of the material is improved. According to the results of the embodiment, the specific surface area of ​​the municipal sludge-based biochar material provided by the present invention is as high as 294.73m 2 / g, and its saturated adsorption capacity for tetracycline is about twice that of medium- and high-temperature municipal sludge biochar, making it a new type of material with excellent performance.

[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing ultra-high temperature municipal sludge-based biochar material, characterized in that: It includes the following steps: (1) Mixing municipal sludge, a carbon source and water to obtain a precursor; (2) After the precursor is carbonized, water vapor is introduced into the precursor for activation to obtain the ultra-high temperature municipal sludge-based biochar material.

2. The method for preparing ultra-high temperature municipal sludge-based biochar material according to claim 1, characterized in that: The particle size of the municipal sludge in step (1) is ≥40 mesh.

3. The method for preparing ultra-high temperature municipal sludge-based biochar material according to claim 1 or 2, characterized in that: In step (1), the mass volume ratio of municipal sludge, carbon source and water is 40-60 g:15-30 g:80-120 mL; The carbon source is one or more of agricultural waste, livestock waste, urban organic waste and invasive plants.

4. The method for preparing ultra-high temperature municipal sludge-based biochar material according to claim 3, characterized in that: The mixing temperature in step (1) is 60 to 100° C. and the mixing time is 20 to 30 hours.

5. The method for preparing ultra-high temperature municipal sludge-based biochar material according to claim 1, 2 or 4, characterized in that: The heating rate of carbonization in step (2) is 3-10°C / min, and the nitrogen flow rate is 80-150mL / min.

6. The method for preparing ultra-high temperature municipal sludge-based biochar material according to claim 5, characterized in that: The target temperature of carbonization in step (2) is 1100-1200° C., and the holding time is 0.5-2 h.

7. The method for preparing ultra-high temperature municipal sewage sludge-based biochar material according to claim 1 or 6, characterized in that: In step (2), the flow rate of water vapor is 80 to 500 mL / min, and the activation time is 30 to 90 min.

8. The ultra-high temperature municipal sludge-based biochar material prepared by the method for preparing the ultra-high temperature municipal sludge-based biochar material according to any one of claims 1 to 7.

9. Use of the ultra-high temperature municipal sludge-based biochar material according to claim 8 in pollutant adsorption.

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