Preparation method of biomass activated carbon

Abstract

The invention relates to a preparation method of biomass activated carbon. The preparation method of the biomass activated carbon comprises the following steps: placing biomass in a reactor, coating the reactor with quartz sand, and then carrying out carbonization treatment to obtain the activated carbon. The preparation method of the biomass activated carbon is simple in process, low in cost, low in energy consumption, economical and environment-friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of activated carbon, and particularly relates to a preparation method of biomass activated carbon. Background Art

[0002] Due to its porous structure, high specific surface area and good adsorption performance, activated carbon is widely used in fields such as environmental protection and energy storage. Among the current methods for preparing activated carbon, biomass materials are converted into activated carbon through chemical activation, physical activation or a combination of both. The operation process is complex, requires atmosphere protection, and generates a large amount of tar.

[0003] The sand bath method is a method that realizes uniform heat transfer by controlling the temperature and using sand as a heat transfer medium. This method is a heating method with simple process, low energy consumption and high efficiency, and is particularly beneficial for the regulation of pore structure and the development of green processes.

[0004] In view of this, the present invention proposes a new preparation method of activated carbon. By using the sand bath method to prepare biomass activated carbon and utilizing the gradient conduction of the sand bath medium and the in-situ pore channel regulation technology, the high specific surface area, hierarchical pore structure and green production (without chemical activators) of biomass activated carbon are realized. At the same time, the whole process does not require atmosphere protection, no activator is needed, and no tar is generated. Summary of the Invention

[0005] The invention object of the present invention is to provide a preparation method of biomass activated carbon, which has a simple process, low cost, low energy consumption, is economical and environmentally friendly, and provides a new idea for the design of biomass activated carbon materials.

[0006] In order to achieve the above object, the technical solution adopted is as follows:

[0007] A preparation method of biomass activated carbon is as follows: Place biomass in a reactor, wrap the reactor with quartz sand, and then carry out carbonization treatment to obtain the activated carbon.

[0008] Further, the biomass is cotton stalks and orange peels.

[0009] Further, the biomass is dry powder with a particle size of 80-120 mesh.

[0010] Still further, the particle size of the biomass is 80 mesh.

[0011] Further, the particle size of the quartz sand is 0.25-0.65 mm.

[0012] Still further, the particle size of the quartz sand is 0.55 mm.

[0013] Further, the carbonization is carried out in an oxygen atmosphere.

[0014] Further, the heating rate of the carbonization treatment is 5-20 °C / min, the carbonization temperature is 700-900 °C, and the time is 1.5 h-3 h.

[0015] Still further, the heating rate of the carbonization treatment is 10 °C / min, the carbonization temperature is 800 °C, and the time is 2 h.

[0016] A biomass activated carbon is prepared by the above preparation method.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The preparation method of the biomass activated carbon described in the present invention is a method for preparing biomass activated carbon by using a sand bath method, which includes the following steps: washing and drying biomass such as cotton stalks and orange peels, and grinding the dried biomass materials for later use. Then, put them into a crucible and wrap them with quartz sand for synchronous calcination and activation. It has the following advantages:

[0019] 1. The technical solution of the present invention uses peel waste as raw material, which is beneficial to environmental protection and effectively reduces the cost of preparing activated carbon.

[0020] 2. The technical solution of the present invention prepares a biomass activated carbon material by a sand bath method. This preparation method has the advantages of being green and environmentally friendly, simple in process, low in energy consumption, economical and efficient, etc.

[0021] 3. The technical solution of the present invention realizes synchronous pyrolysis and activation by a sand bath method, and uses the sand to uniformly transfer heat, avoiding the destruction of the pore structure caused by uneven heat.

[0022] 4. In the prior art, the preparation of activated carbon generally needs to be carried out under anaerobic conditions to avoid the production of oxides. Compared with the prior art, the technical solution of the present invention can successfully prepare activated carbon in an oxygen atmosphere, with simpler conditions and lower costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the process flow chart of the present invention;

[0024] Figure 2 is the schematic diagram of the sand bath device of the present invention;

[0025] Figure 3 is the Raman diagram of the activated carbon described in Example 1 of the present invention;

[0026] Figure 4 is the nitrogen isothermal adsorption and desorption curve of the activated carbon described in Example 1 of the present invention;

[0027] Figure 5 It is the pore size distribution curve of the biomass activated carbon described in Embodiment 1 of the present invention.

[0028] In the figure: 1 - quartz sand, 2 - biomass raw material, 3 - crucible, 4 - muffle furnace. Specific Embodiments

[0029] In order to further elaborate on a method for preparing a biomass activated carbon according to the present invention and achieve the expected invention purpose, the following, in combination with preferred embodiments, details the specific embodiments, structures, features, and effects of a method for preparing a biomass activated carbon according to the present invention as follows. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0030] The following will further introduce in detail a method for preparing a biomass activated carbon according to the present invention in combination with specific embodiments:

[0031] A method for preparing a biomass activated carbon according to the present invention is a method for preparing biomass activated carbon by a sand bath method. The whole process does not require atmosphere protection, does not require an activator, and does not produce tar, and has the advantages of wide raw material sources, simple process, environmental protection and high efficiency, and low cost. In addition, the activated carbon obtained by the preparation method has a large specific surface area and high activity. The technical solution of the present invention is specifically as follows:

[0032] A method for preparing a biomass activated carbon is: placing biomass in a reactor, wrapping the reactor with quartz sand, and then performing synchronous calcination and activation treatment to obtain the activated carbon.

[0033] The mechanism of the above technical solution is: in an air atmosphere, using quartz sand as a heat transfer medium to achieve efficient carbonization activation and in-situ pore channel regulation, thereby affecting its microstructure. These results show that the preparation method of the present invention can achieve high specific surface area, hierarchical pore structure and green production (without chemical activator) of biomass activated carbon, further confirming the advantages of this heat treatment process.

[0034] Preferably, the biomass is cotton stalks, orange peels, etc.

[0035] In the above technical solution, the treatment of biomass before being prepared into activated carbon is: washing it clean with water, drying, grinding and pulverizing to obtain biomass powder with uniform particle size. Among them, the drying is vacuum drying, the temperature is 85 - 95 °C, and the time is 10 - 14 h. Preferably, the drying temperature is 80 °C and the time is 12 h.

[0036] Preferably, the biomass is dry powder with a particle size of 80 - 120 mesh.

[0037] Further preferably, the particle size of the biomass is 80 mesh.

[0038] Preferably, the particle size of the quartz sand is 0.25 - 0.65 mm.

[0039] Further preferably, the particle size of the quartz sand is 0.55 mm.

[0040] Preferably, the carbonization is carried out in an oxygen atmosphere.

[0041] Preferably, the heating rate of the carbonization treatment is 5 - 20 °C / min, the carbonization temperature is 700 - 900 °C, and the time is 1.5 h - 3 h.

[0042] Further preferably, the heating rate of the carbonization treatment is 10 °C / min, the carbonization temperature is 800 °C, and the time is 2 h.

[0043] Example 1.

[0044] Combined with Figure 1-2 Prepare OP-Carbon-0.55 (indicating that the particle size of the quartz sand is 0.55 mm), and the specific operation steps are as follows:

[0045] (1) After cleaning the orange peel with deionized water, vacuum dry it (constant temperature at 80 °C for 12 h), and then crush the dried orange peel to 80 mesh to obtain the biomass powder raw material.

[0046] (2) Then place 1 g of the raw material powder in a 5 mL crucible, and bury the crucible in quartz sand with a particle size of 0.55 mm.

[0047] (3) Use the sand bath method to carbonize and activate the raw material powder, that is, use air as the protective gas, calcine it at high temperature in a muffle furnace, and increase the temperature to 800 °C at a heating rate of 10 °C / min, and keep it at a constant temperature for 2 h to obtain the biomass activated carbon material OP-Carbon-0.55.

[0048] Perform Raman, adsorption performance, and pore size distribution tests on the biomass activated carbon material OP-Carbon-0.55 prepared in Example 1, and the results are as Figures 3-5 shown.

[0049] From Figure 3 it can be seen that the intensity ratio of the D peak (1350 cm -1 ) and the G peak (1600 cm -1 ) in the Raman spectrum is 0.94. This ratio can measure the degree of defects or graphitization in the material. The larger the ratio, the more defects. Therefore, the Raman spectrum data proves that the biomass activated carbon prepared in this example has a high degree of graphitization, the carbon atom layers are arranged orderly, and it can be used to prepare high-quality biomass activated carbon.

[0050] It can be seen from Figure 4 and Figure 5 that in the example, the specific surface area and porosity of the sample were analyzed using a Micromeritics ASAP 2460 instrument in the United States. The specific surface area of the sample in Example 1 was 440.96 m 2 ·g -1 , and the average pore diameter was 2.04 nm, indicating that this heat treatment method can flexibly regulate the pore structure, appropriately increase or decrease the proportion of micropores and mesopores, and thus affect its microstructure.

[0051] Example 2.

[0052] Combined with Figure 1-2 prepare OP-Carbon-0.45 (indicating that the particle size of quartz sand is 0.45 mm), and the specific operation steps are as follows:

[0053] (1) After cleaning the orange peel with deionized water, vacuum dry it (constant temperature at 80 °C for 12 h), and then crush the dried orange peel to 80 mesh to obtain a biomass powder raw material.

[0054] (2) Then place 1 g of the raw material powder in a 5 mL crucible, and then bury the crucible in quartz sand with a particle size of 0.45 mm.

[0055] (3) Use the sand bath method to carbonize and activate the raw material powder, that is, use air as the protective gas, calcine it at high temperature in a muffle furnace, and increase the temperature to 800 °C at a heating rate of 10 °C / min, and keep it at a constant temperature for 2 h to obtain the biomass activated carbon material OP-Carbon-0.45.

[0056] Example 3.

[0057] Combined with Figure 1-2 prepare OP-Carbon-0.65 (indicating that the particle size of quartz sand is 0.65 mm), and the specific operation steps are as follows:

[0058] (1) After cleaning the orange peel with deionized water, vacuum dry it (constant temperature at 80 °C for 12 h), and then crush the dried orange peel to 80 mesh to obtain a biomass powder raw material.

[0059] (2) Then place 1 g of the raw material powder in a 5 mL crucible, and then bury the crucible in quartz sand with a particle size of 0.65 mm.

[0060] (3) Use the sand bath method to carbonize and activate the raw material powder, that is, use air as the protective gas, calcine it at high temperature in a muffle furnace, and increase the temperature to 800 °C at a heating rate of 10 °C / min, and keep it at a constant temperature for 2 h to obtain the biomass activated carbon material OP-Carbon-0.65.

[0061] Example 4.

[0062] Combine Figure 1-2 , and the specific operation steps are as follows:

[0063] (1) After cleaning the orange peel with deionized water, vacuum dry it (constant temperature at 95 °C for 10 h), and then crush the dried orange peel to 120 mesh to obtain the biomass powder raw material.

[0064] (2) Then place 1 g of the raw material powder in a 5 mL crucible, and bury the crucible in quartz sand with a particle size of 0.25 mm.

[0065] (3) Use the sand bath method to carbonize and activate the raw material powder, that is, use air as the protective gas, conduct high-temperature calcination in a muffle furnace, and increase the temperature to 900 °C at a heating rate of 15 °C / min, and keep it at a constant temperature for 1.5 h to obtain the biomass activated carbon material.

[0066] Example 5.

[0067] Combine Figure 1-2 , and the specific operation steps are as follows:

[0068] (1) After cleaning the orange peel with deionized water, vacuum dry it (constant temperature at 85 °C for 14 h), and then crush the dried orange peel to 100 mesh to obtain the biomass powder raw material.

[0069] (2) Then place 1 g of the raw material powder in a 10 mL crucible, and bury the crucible in quartz sand with a particle size of 0.45 mm.

[0070] (3) Use the sand bath method to carbonize and activate the raw material powder, that is, use air as the protective gas, conduct high-temperature calcination in a muffle furnace, and increase the temperature to 850 °C at a heating rate of 10 °C / min, and keep it at a constant temperature for 2 h to obtain the biomass activated carbon material.

[0071] Comparative Example 1.

[0072] (1) After cleaning the orange peel with deionized water, vacuum dry it (constant temperature at 80 °C for 12 h), and then crush the dried orange peel to 80 mesh to obtain the biomass powder raw material.

[0073] (2) Then place 1 g of the biomass powder raw material in an ark, and conduct carbonization and activation treatment in a tube furnace, that is, use nitrogen as the protective gas, conduct high-temperature calcination in the tube furnace, and increase the temperature to 800 °C at a heating rate of 10 °C / min, and keep it at a constant temperature for 2 h to obtain the biomass activated carbon material OP-Carbon.

[0074] Example 6.

[0075] The BET analysis was used to test the specific surface area and porosity of the biomass activated carbons of Examples 1-3 and Comparative Examples, and the measurement results are shown in Table 1.

[0076] Table 1

[0077] Sample <![CDATA[Specific surface area / (m 2 ·g -1 )]]> <![CDATA[Pore volume / (cm 3 ·g -1 )]]> Average pore diameter / (nm) Example 1 440.96 0.1304 2.04 Example 2 375.12 0.1486 2.10 Example 3 424.13 0.0515 2.12 Comparative Example 1 312.67 0.0558 2.06

[0078] Combined with Table 1, it can be seen that the biomass activated carbon prepared by the present invention has a larger specific surface area and porosity.

[0079] Example 7.

[0080] The operating steps of Example 7 are the same as those of Example 1, except that the biomass raw material is cotton stalks.

[0081] Example 8.

[0082] The operating steps of Example 8 are the same as those of Example 1, except that the carbonization and activation treatments are carried out at 700 °C.

[0083] Example 9.

[0084] The specific operating steps are as follows:

[0085] (1) After cleaning the orange peel with deionized water, it is vacuum dried (constant temperature at 80 °C for 12 h), and then the dried orange peel is crushed to 80 mesh to obtain the biomass powder raw material.

[0086] (2) Then 1 g of the raw material powder is placed in a 5 mL crucible, and the crucible is buried in quartz sand with a particle size of 0.55 mm.

[0087] (3) The raw material powder is carbonized and activated by the sand bath method, that is, using air as the protective gas, high-temperature calcination is carried out in a muffle furnace, and the temperature is raised to 800 °C at a heating rate of 5 °C / min and kept constant for 2 h to obtain the biomass activated carbon material.

[0088] Example 10.

[0089] The specific operating steps are as follows:

[0090] (1) After cleaning the orange peel with deionized water, it is vacuum dried (constant temperature at 80 °C for 12 h), and then the dried orange peel is crushed to 80 mesh to obtain the biomass powder raw material.

[0091] (2) Then 1 g of the raw material powder is placed in a 10 mL crucible, and the crucible is buried in quartz sand with a particle size of 0.55 mm.

[0092] (3) The raw material powder is carbonized and activated by the sand bath method, that is, using air as the protective gas, high-temperature calcination is carried out in a muffle furnace, and the temperature is raised to 800 °C at a heating rate of 20 °C / min, and kept at a constant temperature for 2 h to obtain a biomass activated carbon material.

[0093] Example 11.

[0094] The operation steps of Example 11 are the same as those of Example 10, the difference being that the biomass raw material is cotton stalks.

[0095] Example 12.

[0096] The specific operation steps are as follows:

[0097] (1) After washing the orange peel with deionized water, it is vacuum dried (kept at a constant temperature of 80 °C for 12 h), and then the dried orange peel is crushed to 80 mesh to obtain a biomass powder raw material.

[0098] (2) Then, 1 g of the raw material powder is placed in a 5 mL crucible, and the crucible is buried in quartz sand with a particle size of 0.55 mm.

[0099] (3) The raw material powder is carbonized and activated by the sand bath method, that is, using air as the protective gas, high-temperature calcination is carried out in a muffle furnace, and the temperature is raised to 800 °C at a heating rate of 5 °C / min, and kept at a constant temperature for 3 h to obtain a biomass activated carbon material.

[0100] The above is only the preferred embodiment of the embodiments of the present invention, and does not impose any form of limitation on the embodiments of the present invention. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the embodiments of the present invention still fall within the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of biomass activated carbon, characterized in that, The preparation method is as follows: Place the biomass in a reactor, wrap the reactor with quartz sand, and then carry out carbonization treatment to obtain the activated carbon.

2. The preparation method according to claim 1, wherein the biomass is cotton stalks and orange peels.

3. The preparation method according to claim 1, wherein the biomass is dry powder with a particle size of 80-120 mesh.

4. The preparation method according to claim 6, wherein the particle size of the biomass is 80 mesh.

5. The preparation method according to claim 1, wherein the particle size of the quartz sand is 0.25-0.65 mm.

6. The preparation method according to claim 5, wherein the particle size of the quartz sand is 0.55 mm.

7. The preparation method according to claim 1, wherein the carbonization treatment is carried out in an oxygen atmosphere.

8. The preparation method according to claim 1, wherein the heating rate of the carbonization treatment is 5-20 °C / min, the carbonization temperature is 700-900 °C, and the time is 1.5-3 h.

9. The preparation method according to claim 8, wherein the heating rate of the carbonization treatment is 10 °C / min, the carbonization temperature is 800 °C, and the time is 2 h.

10. A biomass activated carbon, characterized in that, The biomass activated carbon is prepared by the preparation method according to any one of claims 1-9.

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