Preparation method and device of ferric oxide composite nano material

Abstract

The invention provides a preparation method of a graphene and ferric oxide composite nanomaterial and a derivative thereof. Comprising the following steps: preparing a graphene and ferric oxide composite nano material (GF), preparing a graphene and ferric oxide composite nano material (HGF) pre-oxidized by hydrogen peroxide, and preparing a nitrogen-doped graphene and ferric oxide composite material (N-GF). According to the preparation method of the ferric oxide composite nano-material, provided by the invention, the ferric oxide nano-particles are uniformly anchored on the graphene nano-sheets through processes of one-step water bath synthesis, pre-oxidation, nitrogen doping and the like to form a rich pore structure, so that more active sites and a relatively large sodium storage space can be provided; meanwhile, the electron transmission path is shortened.

Description

Technical Field

[0001] This invention relates to the field of nanomaterial preparation, and in particular to a method and apparatus for preparing ferric oxide composite nanomaterials. Background Technology

[0002] With the rapid development of the new energy industry, sodium ion storage devices have attracted widespread attention due to their advantages such as abundant sodium resources, low cost and high energy density. Electrochemical oxidation-reduction reactions of metal oxides provide a new way to construct the negative electrode of high-capacity sodium ion storage devices. Among them, ferric oxide, as an environmentally friendly metal oxide, has the potential for high-efficiency sodium storage.

[0003] However, pure ferric oxide materials suffer from poor conductivity and significant volume expansion during cycling, resulting in poor electrochemical performance for sodium storage and limiting their practical applications. Graphene has a two-dimensional layered structure with high conductivity and high specific surface area. Combining it with ferric oxide can improve material performance, but existing composite methods still have defects such as insufficient optimization of the microstructure of composite materials, insufficient active sites, and long electron transport paths. This makes it difficult for the specific capacity, rate performance, and cycling stability of composite nanomaterials to meet the requirements of high-performance sodium storage devices.

[0004] Therefore, it is necessary to provide a method for preparing ferric oxide composite nanomaterials to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a method for preparing ferric oxide composite nanomaterials, which solves the problems of existing composite methods, such as insufficient optimization of the microstructure of composite materials, insufficient active sites, and long electron transport paths, which make it difficult for the specific capacity, rate performance and cycle stability of composite nanomaterials to meet the requirements of high-performance sodium storage devices.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for preparing ferric oxide composite nanomaterials, comprising the following steps:

[0007] Preparation of composite nanomaterials of S1, graphene and ferric oxide;

[0008] S11. 160 mg of graphene oxide was prepared into a solution with a concentration of 2 mg / mL, and then ultrasonically dispersed for 2 hours to obtain graphene oxide.

[0009] S12. Slowly add 100ml of a solution containing 0.901g of ferric chloride hexahydrate to the graphene oxide solution in a 250ml round-bottom flask. After stirring for 2.5 hours, add 0.096ml of hydrazine hydrate, a reducing agent with a weight percentage of 85%.

[0010] S13. Place the mixed solution in an 80°C water bath and react for 24 hours, keeping the mixture stirred throughout the low-temperature hydrothermal process.

[0011] S14. The low-temperature hydrothermal reaction products were treated by vacuum filtration, washing, and freeze-drying to obtain ferric oxide nanocomposite materials.

[0012] S2. The preparation of graphene and ferric oxide composite nanomaterials (HGF) pre-oxidized with hydrogen peroxide includes the following steps:

[0013] S21. Graphene oxide (GO) is obtained by following the first step of the above-mentioned preparation of ferric oxide composite nanomaterials.

[0014] S22. According to the volume ratio of graphene oxide solution to hydrogen peroxide solution of 10:1, 8 mg of hydrogen peroxide was added to the graphene oxide solution, and HGO was obtained by reacting in a high temperature water bath at 96°C for 2 hours with constant stirring.

[0015] S23. The subsequent steps are the same as the second to fourth steps in the preparation of ferric oxide composite nanomaterials, namely, adding ferric chloride hexahydrate solution and hydrazine hydrate, reacting in an 80°C water bath for 24 hours, and then undergoing vacuum filtration, washing, freeze drying and other treatments to obtain HGF nanocomposite materials.

[0016] The preparation of S3, nitrogen-doped graphene and ferric oxide composite material (N-GF) includes the following steps:

[0017] S31. Ferric oxide nanocomposite material was obtained according to the above preparation method of ferric oxide composite nanomaterial;

[0018] S32. Anneal the ferric oxide composite nanomaterial sample at 300°C for 2 hours under argon atmosphere;

[0019] S33. The annealed sample was heated at 600°C for 2 hours in an ammonia atmosphere to dope nitrogen atoms and obtain an N-GF sample.

[0020] Preferably, the ultrasonic dispersion power in S11 is 200-300W, and the concentration of the ferric chloride hexahydrate solution in S21 is 0.03mol / L.

[0021] Preferably, the vacuum filtration uses a 0.22μm filter membrane, and the washing process involves washing with deionized water and anhydrous ethanol multiple times in sequence.

[0022] A device for preparing ferric oxide composite nanomaterials includes: a first drying oven, two second drying ovens, multiple adjustment components, multiple placement plates, multiple fixing components, and multiple splicing components;

[0023] Two second drying boxes are disposed on both sides of the first drying box via two of the splicing components;

[0024] The plurality of the adjustment components are respectively disposed inside the first drying chamber and the two second drying chambers;

[0025] The plurality of placement plates are respectively disposed inside the first drying box and the plurality of second drying boxes;

[0026] The plurality of fixing components are respectively disposed at the bottom of the plurality of placement plates.

[0027] Preferably, the adjustment assembly includes a fixing plate, an adjustment groove, multiple adjustment blocks, and multiple U-shaped fixing blocks. The fixing plate is connected to the rear interior of the first drying chamber and the two second drying chambers. The adjustment groove is formed on the surface of the fixing rod. The multiple adjustment blocks are slidably connected to the interior of the adjustment groove. The multiple U-shaped blocks are respectively installed on the surface of the multiple adjustment blocks.

[0028] Preferably, the fixing component includes an L-shaped fixing block and a bolt, the L-shaped fixing block being installed at the bottom of the placement plate, and the bolt being disposed inside the L-shaped fixing block.

[0029] Preferably, the splicing assembly includes a splicing sleeve and a splicing block. The splicing sleeve is connected to the side of the first drying box, and the splicing block is pluggable and inserted into the interior of the splicing sleeve and connected to the second drying box.

[0030] Preferably, support seats are connected to both sides of the surface of the first drying oven.

[0031] Preferably, both the first drying oven and the second drying oven have doors connected to their surfaces by hinges.

[0032] Preferably, a limiting component is provided between the support base and the second drying box. The limiting component includes a groove, an external threaded block, a pad, and a threaded sleeve. The groove is formed on the side of the support frame, the external threaded block is connected to the bottom of the second drying box, the pad is sleeved on the surface of the external threaded block, and the threaded sleeve is threadedly connected to the surface of the external threaded block.

[0033] Compared with related technologies, the method for preparing ferric oxide composite nanomaterials provided by this invention has the following beneficial effects:

[0034] This invention provides a method for preparing ferric oxide composite nanomaterials. Through one-step water bath synthesis, pre-oxidation, nitrogen doping and other processes, ferric oxide nanoparticles are uniformly anchored on graphene nanosheets to form a rich porous structure, which can provide more active sites and larger sodium storage space, while shortening the electron transport path.

[0035] The high conductivity of graphene enhances the overall conductivity of the composite material. The pre-oxidation process increases the specific surface area and micropore ratio of the material, while nitrogen doping further improves the conductivity and buffers the volume expansion, giving the composite material high specific capacity, good rate performance and cycle stability.

[0036] The preparation conditions, such as water bath synthesis and annealing, are relatively mild, simple to operate and easy to control, and suitable for large-scale production. This provides feasible technical support for the practical application of ferric oxide composite nanomaterials in sodium storage devices such as sodium-ion supercapacitors. Attached Figure Description

[0037] Figure 1 A schematic diagram of the structure of a first embodiment of an apparatus for preparing ferric oxide composite nanomaterials provided by the present invention;

[0038] Figure 2 for Figure 1 The enlarged schematic diagram of part A shown below;

[0039] Figure 3 for Figure 1 The enlarged schematic diagram of section B is shown below;

[0040] Figure 4 for Figure 1 A three-dimensional structural schematic diagram of the preparation apparatus shown;

[0041] Figure 5 for Figure 4 The enlarged schematic diagram of section C is shown below;

[0042] Figure 6 This is a schematic diagram of the structure of a second embodiment of the apparatus for preparing ferric oxide composite nanomaterials provided by the present invention;

[0043] Figure 7 for Figure 6 The enlarged schematic diagram of part D is shown.

[0044] The diagram is labeled: 1. First drying oven; 2. Second drying oven;

[0045] 3. Adjustment component; 31. Fixing plate; 32. Adjustment groove; 33. Adjustment block; 34. U-shaped fixing block;

[0046] 4. Placement board;

[0047] 5. Fixing components; 51. L-shaped fixing block; 52. Bolt;

[0048] 6. Splicing components; 61. Splicing sleeves; 62. Splicing blocks;

[0049] 7. Box door; 8. Support base;

[0050] 9. Limiting component; 91. Groove; 92. External thread block; 93. Pad; 94. Threaded sleeve. Detailed Implementation

[0051] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0052] A method and apparatus for preparing ferric oxide composite nanomaterials, comprising the following steps:

[0053] Preparation of composite nanomaterials of S1, graphene and ferric oxide;

[0054] S11. 160 mg of graphene oxide was prepared into a solution with a concentration of 2 mg / mL, and then ultrasonically dispersed for 2 hours to obtain graphene oxide.

[0055] S12. Slowly add 100ml of a solution containing 0.901g of ferric chloride hexahydrate to the graphene oxide solution in a 250ml round-bottom flask. After stirring for 2.5 hours, add 0.096ml of hydrazine hydrate, a reducing agent with a weight percentage of 85%.

[0056] S13. Place the mixed solution in an 80°C water bath and react for 24 hours, keeping the mixture stirred throughout the low-temperature hydrothermal process.

[0057] S14. The low-temperature hydrothermal reaction products were treated by vacuum filtration, washing, and freeze-drying to obtain ferric oxide nanocomposite materials.

[0058] S2. The preparation of graphene and ferric oxide composite nanomaterials (HGF) pre-oxidized with hydrogen peroxide includes the following steps:

[0059] S21. Graphene oxide (GO) is obtained by following the first step of the above-mentioned preparation of ferric oxide composite nanomaterials.

[0060] S22. According to the volume ratio of graphene oxide solution to hydrogen peroxide solution of 10:1, 8 mg of hydrogen peroxide was added to the graphene oxide solution, and HGO was obtained by reacting in a high temperature water bath at 96°C for 2 hours with constant stirring.

[0061] S23. The subsequent steps are the same as the second to fourth steps in the preparation of ferric oxide composite nanomaterials, namely, adding ferric chloride hexahydrate solution and hydrazine hydrate, reacting in an 80°C water bath for 24 hours, and then undergoing vacuum filtration, washing, freeze drying and other treatments to obtain HGF nanocomposite materials.

[0062] The preparation of S3, nitrogen-doped graphene and ferric oxide composite material (N-GF) includes the following steps:

[0063] S31. Ferric oxide nanocomposite material was obtained according to the above preparation method of ferric oxide composite nanomaterial;

[0064] S32. Anneal the ferric oxide composite nanomaterial sample at 300°C for 2 hours under argon atmosphere;

[0065] S33. The annealed sample was heated at 600°C for 2 hours in an ammonia atmosphere to dope nitrogen atoms and obtain an N-GF sample.

[0066] The ultrasonic dispersion power in S11 is 200-300W, and the concentration of the ferric chloride hexahydrate solution in S21 is 0.03mol / L.

[0067] The vacuum filtration uses a 0.22μm filter membrane, and the washing process involves washing with deionized water and anhydrous ethanol multiple times in sequence.

[0068] Compared with related technologies, the method for preparing ferric oxide composite nanomaterials provided by this invention has the following beneficial effects:

[0069] This invention provides a method for preparing ferric oxide composite nanomaterials. Through one-step water bath synthesis, pre-oxidation, nitrogen doping and other processes, ferric oxide nanoparticles are uniformly anchored on graphene nanosheets to form a rich porous structure, which can provide more active sites and larger sodium storage space, while shortening the electron transport path.

[0070] The high conductivity of graphene enhances the overall conductivity of the composite material. The pre-oxidation process increases the specific surface area and micropore ratio of the material, while nitrogen doping further improves the conductivity and buffers the volume expansion, giving the composite material high specific capacity, good rate performance and cycle stability.

[0071] The preparation conditions, such as water bath synthesis and annealing, are relatively mild, simple to operate and easy to control, and suitable for large-scale production. This provides feasible technical support for the practical application of ferric oxide composite nanomaterials in sodium storage devices such as sodium-ion supercapacitors.

[0072] First Embodiment

[0073] Please refer to the following: Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 ,in, Figure 1 A schematic diagram of the structure of a first embodiment of an apparatus for preparing ferric oxide composite nanomaterials provided by the present invention; Figure 2 for Figure 1 The enlarged schematic diagram of part A shown below; Figure 3 for Figure 1The enlarged schematic diagram of section B is shown below; Figure 4 for Figure 1 A three-dimensional structural schematic diagram of the preparation apparatus shown; Figure 5 for Figure 4 The enlarged schematic diagram of section C is shown. An apparatus for preparing ferric oxide composite nanomaterials includes: a first drying oven 1, two second drying ovens 2, multiple adjusting components 3, multiple placement plates 4, multiple fixing components 5, and multiple splicing components 6;

[0074] Two second drying boxes 2 are disposed on both sides of the first drying box 1 via two splicing components 6;

[0075] Multiple adjustment components 3 are respectively disposed inside the first drying chamber 1 and the two second drying chambers 2;

[0076] Multiple placement plates 4 are respectively disposed inside the first drying box 1 and multiple second drying boxes 2;

[0077] Multiple fixing components 5 are respectively disposed at the bottom of multiple placement plates 4.

[0078] The adjustment assembly 3 includes a fixing plate 31, an adjustment groove 32, multiple adjustment blocks 33, and multiple U-shaped fixing blocks 34. The fixing plate 31 is connected to the rear interior of the first drying chamber 1 and the two second drying chambers 2. The adjustment groove 32 is formed on the surface of the fixing rod 31. The multiple adjustment blocks 33 are slidably connected to the interior of the adjustment groove 32. The multiple U-shaped blocks 34 are respectively installed on the surface of the multiple adjustment blocks 33.

[0079] The fixing component 5 includes an L-shaped fixing block 51 and a bolt 52. The L-shaped fixing block 51 is installed on the bottom of the placement plate 4, and the bolt 52 is disposed inside the L-shaped fixing block 51.

[0080] The splicing assembly 6 includes a splicing sleeve 61 and a splicing block 62. The splicing sleeve 61 is connected to the side of the first drying box 1, and the splicing block 62 is pluggable and inserted into the inside of the splicing sleeve 61 and connected to the second drying box 2.

[0081] Both sides of the surface of the first drying oven 1 are connected to support bases 8.

[0082] Both the first drying oven 1 and the second drying oven 2 have doors 7 connected to their surfaces by hinges.

[0083] By replacing the fixing component 5 on the placement plate 4, it is possible to accommodate the washing operation after vacuum filtration and the constant temperature placement of the hydrothermal reaction vessel.

[0084] By adding a motor-driven adjustment block 33 to the adjustment component 3, combined with a temperature sensor and control system, the temperature of different layers of the placement plate 4 can be adjusted in real time (e.g., the upper layer is used for drying GF samples, and the lower layer is used for pre-oxidation post-treatment of HGF samples), thereby improving experimental efficiency.

[0085] A pressure sensor is added to door 7, which will automatically alarm when the pressure inside the drying oven is abnormal, thus preventing sample damage caused by loss of vacuum control.

[0086] Space adjustment mechanism: The surface of the fixed plate 31 in the adjustment component 3 is provided with an adjustment groove 32. The adjustment block 33 can slide along the groove and fix the placement plate 4 through the U-shaped fixed block 34, so as to realize the height of the multi-layer placement plate 4 can be freely adjusted to meet the needs of simultaneous processing of samples of different quantities or volumes (such as drying multiple groups of GF and HGF samples at the same time).

[0087] Splicing expansion function: The splicing sleeve 61 and splicing block 62 of the splicing component 6 are connected by plug-in type, which can quickly fix the second drying box 2 to both sides of the first drying box 1, expand the processing capacity of the device, and is suitable for batch preparation scenarios (such as the simultaneous freeze-drying of multiple groups of samples after vacuum filtration in the experiment).

[0088] Stable support design: The support seats 8 on both sides of the first drying oven 1 provide stable support for the whole device. Together with the sealing structure of the oven door 7, they can maintain the uniformity of temperature and humidity inside the drying oven and ensure the stability of the freeze-drying or heat treatment process.

[0089] Compared with related technologies, the ferric oxide composite nanomaterial preparation device provided by the present invention has the following beneficial effects:

[0090] This invention provides a method for preparing ferric oxide composite nanomaterials. Multiple adjustment components 3 are provided inside the first drying oven 1 and the two second drying ovens 2, which are used in conjunction with multiple placement plates 4 with fixing components 5. The spacing between the multiple placement plates 4 can be adjusted according to the usage. A splicing component 6 is provided between the first drying oven 1 and the two second drying ovens 2, which can be used to increase the number of second drying ovens 2 according to the usage.

[0091] Third Embodiment

[0092] Please refer to the following: Figure 6 and Figure 7 Based on the ferric oxide composite nanomaterial preparation apparatus provided in the first embodiment of this application, the third embodiment of this application proposes another ferric oxide composite nanomaterial preparation apparatus. The third embodiment is merely a preferred embodiment of the first embodiment, and the implementation of the third embodiment will not affect the separate implementation of the first embodiment.

[0093] Specifically, the difference in the ferric oxide composite nanomaterial preparation device provided in the third embodiment of this application is that, in the ferric oxide composite nanomaterial preparation device, a limiting component 9 is provided between the support base 8 and the second drying box 2. The limiting component 9 includes a groove 91, an external threaded block 92, a pad 93 and a threaded sleeve 94. The groove 91 is opened on the side of the support frame 8, the external threaded block 92 is connected to the bottom of the second drying box 2, the pad 93 is sleeved on the surface of the external threaded block 92, and the threaded sleeve 94 is threadedly connected to the surface of the external threaded block 92.

[0094] The groove 91 facilitates the movement of the external threaded block 92 into the support frame 8, and the use of the pad 93 increases the fixation between the external threaded block 92 and the threaded sleeve 94.

[0095] The working principle of the ferric oxide composite nanomaterial preparation device provided by this invention is as follows:

[0096] In use, after the second drying box 2 is installed on one side of the first drying box 1, the external threaded block 92 at the bottom of the second drying box 2 is moved into the inside of the groove 91. After the external threaded block 92 is installed into the inside of the groove 91, the pad 93 is placed on the surface of the external threaded block 92, and finally the threaded sleeve 94 is threadedly connected to the external threaded block 92.

[0097] Compared with related technologies, the ferric oxide composite nanomaterial preparation device provided by the present invention has the following beneficial effects:

[0098] This invention provides a method for preparing ferric oxide composite nanomaterials. A groove 91, an external threaded block 92, a pad 93, and a threaded sleeve 94 are provided between the support frame 8 and the second drying box 2 to facilitate secondary fixation when the second drying box 2 is installed between the first drying box 1 and the second drying box 2.

[0099] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing ferric oxide composite nanomaterials, characterized in that, Includes the following steps: Preparation of composite nanomaterials of S1, graphene and ferric oxide; S11. 160 mg of graphene oxide was prepared into a solution with a concentration of 2 mg / mL, and then ultrasonically dispersed for 2 hours to obtain graphene oxide. S12. Slowly add 100ml of a solution containing 0.901g of ferric chloride hexahydrate to the graphene oxide solution in a 250ml round-bottom flask. After stirring for 2.5 hours, add 0.096ml of hydrazine hydrate, a reducing agent with a weight percentage of 85%. S13. Place the mixed solution in an 80°C water bath and react for 24 hours, keeping the mixture stirred throughout the low-temperature hydrothermal process. S14. The low-temperature hydrothermal reaction products were treated by vacuum filtration, washing, and freeze-drying to obtain ferric oxide nanocomposite materials. S2. The preparation of graphene and ferric oxide composite nanomaterials (HGF) pre-oxidized with hydrogen peroxide includes the following steps: S21. Graphene oxide (GO) is obtained by following the first step of the above-mentioned preparation of ferric oxide composite nanomaterials. S22. According to the volume ratio of graphene oxide solution to hydrogen peroxide solution of 10:1, 8 mg of hydrogen peroxide was added to the graphene oxide solution, and HGO was obtained by reacting in a high temperature water bath at 96°C for 2 hours with constant stirring. S23. The subsequent steps are the same as the second to fourth steps in the preparation of ferric oxide composite nanomaterials, namely, adding ferric chloride hexahydrate solution and hydrazine hydrate, reacting in an 80°C water bath for 24 hours, and then undergoing vacuum filtration, washing, freeze drying and other treatments to obtain HGF nanocomposite materials. The preparation of S3, nitrogen-doped graphene and ferric oxide composite material (N-GF) includes the following steps: S31. Ferric oxide nanocomposite material was obtained according to the above preparation method of ferric oxide composite nanomaterial; S32. Anneal the ferric oxide composite nanomaterial sample at 300°C for 2 hours under argon atmosphere; S33. The annealed sample was heated at 600°C for 2 hours in an ammonia atmosphere to dope nitrogen atoms and obtain an N-GF sample.

2. The method for preparing ferric oxide composite nanomaterials according to claim 1, characterized in that, The ultrasonic dispersion power in S11 is 200-300W, and the concentration of the ferric chloride hexahydrate solution in S21 is 0.03mol / L.

3. The method for preparing ferric oxide composite nanomaterials according to claim 1, characterized in that, The vacuum filtration uses a 0.22μm filter membrane, and the washing process involves washing with deionized water and anhydrous ethanol multiple times in sequence.

4. An apparatus for preparing ferric oxide composite nanomaterials, comprising the method for preparing ferric oxide composite nanomaterials as described in any one of claims 1 to 3, characterized in that, include: The system comprises a first drying chamber, two second drying chambers, multiple adjustment components, multiple placement plates, multiple fixing components, and multiple splicing components. Two second drying boxes are disposed on both sides of the first drying box via two of the splicing components; The plurality of the adjustment components are respectively disposed inside the first drying chamber and the two second drying chambers; The plurality of placement plates are respectively disposed inside the first drying box and the plurality of second drying boxes; The plurality of fixing components are respectively disposed at the bottom of the plurality of placement plates.

5. The apparatus for preparing ferric oxide composite nanomaterials according to claim 4, characterized in that, The adjustment assembly includes a fixed plate, an adjustment groove, multiple adjustment blocks, and multiple U-shaped fixed blocks. The fixed plate is connected to the rear interior of the first drying chamber and the two second drying chambers. The adjustment groove is opened on the surface of the fixed rod. The multiple adjustment blocks are slidably connected to the interior of the adjustment groove. The multiple U-shaped blocks are respectively installed on the surface of the multiple adjustment blocks.

6. The apparatus for preparing ferric oxide composite nanomaterials according to claim 4, characterized in that, The fixing component includes an L-shaped fixing block and a bolt. The L-shaped fixing block is installed at the bottom of the placement plate, and the bolt is located inside the L-shaped fixing block.

7. The apparatus for preparing ferric oxide composite nanomaterials according to claim 5, characterized in that, The splicing assembly includes a splicing sleeve and a splicing block. The splicing sleeve is connected to the side of the first drying oven, and the splicing block is pluggable and inserted into the inside of the splicing sleeve and connected to the second drying oven.

8. The apparatus for preparing ferric oxide composite nanomaterials according to claim 5, characterized in that, Support seats are connected to both sides of the surface of the first drying oven.

9. The apparatus for preparing ferric oxide composite nanomaterials according to claim 5, characterized in that, Both the first drying oven and the second drying oven have doors connected to their surfaces by hinges.

10. The apparatus for preparing ferric oxide composite nanomaterials according to claim 8, characterized in that, A limiting component is provided between the support base and the second drying box. The limiting component includes a groove, an external threaded block, a pad, and a threaded sleeve. The groove is formed on the side of the support frame. The external threaded block is connected to the bottom of the second drying box. The pad is fitted onto the surface of the external threaded block. The threaded sleeve is threaded onto the surface of the external threaded block.

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