A ball milling method for preparing long afterglow material by using carbon-containing waste liquid

Abstract

This invention discloses a ball milling method for preparing long afterglow materials using carbon-containing waste liquid. The method includes: mixing a carbon-containing waste liquid with a matrix material to obtain a mixture, wherein the carbon-containing waste liquid includes small-sized carbon, which is at least one of carbon nanotube fragments, graphene fragments, and nano-carbon black fragments; the matrix material is boric acid or borate crystals. The method for obtaining the carbon-containing waste liquid includes: adjusting the pH of the carbon-containing waste liquid to 5-6, centrifuging, and collecting the supernatant; ball milling the mixture, and drying to obtain the long afterglow material. The long afterglow material contains 0.1-2 wt% small-sized carbon, the ball milling time is at least 4 hours, and the ball mill rotation speed is 300-800 r / min. This invention is the first to propose the direct preparation of long afterglow materials using carbon-containing waste liquid as raw material, realizing the high-value resource utilization of carbon-containing waste liquid.

Description

Technical Field

[0001] This invention belongs to the field of long afterglow material technology, specifically relating to a ball milling method for preparing long afterglow materials using carbon-containing waste liquid. Background Technology

[0002] During the functionalization or chemical modification of carbon materials (such as graphene, carbon nanotubes, carbon black nanofibers, etc.), a large amount of process waste liquid containing small-sized carbon is generated. The small-sized carbon in the process waste liquid is small in size, has a large specific surface area, and contains oxygen-containing functional groups. Therefore, it is tightly bound to water molecules and is difficult to separate effectively by conventional methods such as precipitation, filtration, or centrifugation. This brings great difficulties and cost pressure to wastewater treatment, and also poses a potential threat to the ecological environment.

[0003] Meanwhile, carbon-based nanomaterials have become a research hotspot in the field of long-afterglow luminescent materials in recent years due to their excellent photoluminescence properties. Existing literature has reported the long-afterglow characteristics of zero-dimensional carbon dots such as graphene quantum dots. However, the small-sized carbon in process waste liquids is neither as zero-dimensional as quantum dots nor as small as typical carbon particles. Current research on non-zero-dimensional carbon materials is insufficient, especially lacking feasible processes for directly converting small-sized carbon in waste liquids into high-performance long-afterglow materials. Furthermore, existing methods for preparing carbon-based long-afterglow materials mostly rely on hydrothermal, solvothermal, and ultrasonic dispersion methods. These methods are complex, energy-intensive, and have poor safety, and are difficult to integrate with large-scale industrial waste liquid treatment, limiting their application in practical production.

[0004] Therefore, there is an urgent need to develop a simple, safe, efficient, and industrially scaleable method that can directly convert small-sized carbon in carbon-containing waste liquid into functional materials with long afterglow properties, thereby realizing the resource utilization and high-value utilization of waste liquid, while reducing waste liquid treatment costs and environmental risks. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a ball milling method for preparing long afterglow materials using carbon-containing waste liquid, aiming to achieve efficient resource utilization of carbon-containing waste liquid.

[0006] Another object of the present invention is to provide a long afterglow material obtained by the ball milling method described above for preparing long afterglow materials using carbon-containing waste liquid.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] A ball milling method for preparing long afterglow materials using carbon-containing waste liquid includes the following steps:

[0009] Step 1: Mix the carbon-containing liquid and the matrix material to obtain a mixture. The carbon-containing liquid includes small-sized carbon, which is at least one of carbon nanotube fragments, graphene fragments, and nano-carbon black fragments. The matrix material is boric acid or borate crystals. The method for obtaining the carbon-containing liquid includes: adjusting the pH value of the carbon-containing waste liquid to 5-6, then centrifuging to separate the solid and liquid, and taking the upper clear liquid to obtain the carbon-containing liquid. The centrifugation speed is 3000-9000 r / min, and the centrifugation time is 10-20 min.

[0010] In step 1, the particle size of the small carbon particles is 20–50 nm.

[0011] In step 1, the content of small-sized carbon in the carbon-containing solution is 0.01~0.1wt%.

[0012] In step 1, the carbon-containing waste liquid is the waste liquid obtained after functionalizing carbon nanotubes, the waste liquid obtained after functionalizing graphene powder, or the waste liquid obtained after functionalizing nano-carbon black.

[0013] In the above technical solution, the method for obtaining carbon-containing waste liquid includes: placing at least one of carbon nanotubes, graphene powder, and nano-carbon black in nitric acid, stirring under ultrasonic conditions for at least 1 hour, and filtering out the solid to obtain a solution containing carbon-containing waste liquid, wherein the concentration of HNO3 in the nitric acid is 10~15 mol / L. -1 .

[0014] Step 2: The mixture is ball-milled and dried to obtain a long afterglow material (long afterglow material based on carbon-containing waste liquid). The content of small-sized carbon in the long afterglow material is 0.1~2wt%. The ball milling time is at least 4 hours and the rotation speed of the ball mill is 300~800 r / min.

[0015] In step 2, the ball mill uses grinding balls, and the ratio of grinding balls to the mixture is (3~6):1 by mass.

[0016] In step 2, the drying time is 0.5 to 6 hours and the drying temperature is 140 to 190°C.

[0017] In step 2, the ball milling time is preferably 4 to 6 hours.

[0018] The long afterglow material obtained by the ball milling method described above for preparing long afterglow materials using carbon-containing waste liquid.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) This invention proposes for the first time to directly prepare long afterglow materials using carbon-containing waste liquid as raw material, transforming pollutants that are difficult to treat into high-value-added functional materials. This not only provides a new technical path for the harmlessness and resource utilization of carbon-containing waste liquid, effectively avoiding the loss of carbon resources and environmental pollution, but also significantly reduces the cost and difficulty of traditional waste liquid treatment, realizing the high-value utilization of carbon-containing waste liquid.

[0021] (2) This invention employs a "one-step, solvent-free" ball milling process, completely avoiding the high-temperature and high-pressure safety hazards caused by hydrothermal / solvent thermal processes commonly used in existing technologies. It eliminates the need for complex ultrasonic dispersion processes and large amounts of solvent as a dispersion medium, enabling uniform dispersion and composite of small-sized carbon particles in carbon-containing waste liquid within the matrix material. This significantly saves water resources and solvent consumption. Consequently, the subsequent drying steps become very simple and energy-efficient, further reducing production costs and environmental burden. This results in a low-energy-consumption and safe operation of the entire process, making it particularly suitable for large-scale, continuous industrial treatment of carbon-containing waste liquid, demonstrating high feasibility. Attached Figure Description

[0022] Figure 1 This is a TEM image of small-sized carbon particles in the carbon-containing clear liquid of Example 1;

[0023] Figure 2 The images are of the long afterglow material E1 obtained in Example 1 at 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s, 9s and 10s after the UV lamp is turned off;

[0024] Figure 3 The images are of the long afterglow material E2 obtained in Example 2 at 1s, 2s, 3s, 4s, 5s, 6s, 7s, 8s and 9s after the UV lamp was turned off;

[0025] Figure 4 Photographs of the long afterglow material C5 obtained in Comparative Example 5 at 1s, 2s, 3s, 4s and 5s after the UV lamp was turned off;

[0026] Figure 5 Photographs of the long afterglow material C8 obtained in Comparative Example 8 at 1s, 2s, 3s, 4s, 5s, 6s, 7s and 8s after the UV lamp was turned off;

[0027] Figure 6 The afterglow decay curve of the long afterglow material E1 obtained in Example 1 is shown.

[0028] Figure 7 The afterglow decay curve of the long afterglow material C5 obtained in Comparative Example 5 is shown.

[0029] Figure 8 The afterglow decay curve of the long afterglow material C6 obtained in Comparative Example 6 is shown.

[0030] Figure 9 The curves showing the attenuation of afterglow luminescence between the long afterglow material E2 obtained in Example 2 and the long afterglow material C8 obtained in Comparative Example 8 are shown.

[0031] Figure 10 The image shows a comparison of the phosphorescence spectra of the long afterglow material E2 obtained in Example 2 and the long afterglow material C8 obtained in Comparative Example 8 under ultraviolet excitation. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0033] The raw material information in the following examples and comparative examples is as follows:

[0034] Boric acid (analytical grade), potassium borate (analytical grade), sodium borate (analytical grade), nano carbon black, carbon nanotubes, graphene powder, acetylene black, and nitric acid were all purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0035] Experimental Principle: Ball milling serves to uniformly embed small-sized carbon particles into the matrix material, enabling the small-sized carbon and matrix material to form the microscopic composite structure necessary for long afterglow—a structure in which small-sized carbon particles are encapsulated by the matrix—without the need for high-temperature sintering. In previous preparations of inorganic long afterglow materials (such as the invention patent with publication number CN114032101A), ball milling is a pretreatment step, mainly used for mixing and refining raw materials to ensure the uniformity and efficiency of the subsequent high-temperature solid-state reaction (a key step in forming the microscopic structure required for long afterglow materials). However, in this invention, ball milling is the crucial and core step in forming a perfect composite structure between small-sized carbon and the matrix material, not a pretreatment step.

[0036] The carbon-containing waste liquid used in Example 1 was the waste liquid obtained after functionalizing carbon nanotubes; the carbon-containing waste liquid used in Example 2 was the waste liquid obtained after functionalizing graphene powder; and the carbon-containing waste liquid used in Example 3 was the waste liquid obtained after functionalizing nano-carbon black. The method for obtaining the carbon-containing waste liquid in Example 1 included: placing 5g of carbon nanotubes in 500mL of nitric acid (the concentration of HNO3 in the nitric acid was 10mol / L). -1 The carbon nanotubes were functionalized by stirring under ultrasonic (power: 300W) conditions (speed: 200r / min) for 2 hours. The resulting solution after filtering out the solid was used as the carbon-containing waste liquid in Example 1. The method for obtaining the carbon-containing waste liquid in Example 2 was basically the same as that for obtaining the carbon-containing waste liquid in Example 1, except that "carbon nanotubes" were replaced with "graphene powder". The method for obtaining the carbon-containing waste liquid in Example 3 was basically the same as that for obtaining the carbon-containing waste liquid in Example 1, except that "carbon nanotubes" were replaced with "nano-carbon black".

[0037] Example 1

[0038] A ball milling method for preparing long afterglow materials using carbon-containing waste liquid includes the following steps:

[0039] Step 1: At room temperature, mix the carbon-containing liquid and matrix material (by mass, the ratio of carbon-containing liquid to matrix material is 10:1), and stir until a paste is formed to obtain a mixture. The carbon-containing liquid includes small-sized carbon, which is carbon nanotube fragments (particle size approximately 35 nm). The matrix material is boric acid. The method for obtaining the carbon-containing liquid includes: adjusting the pH of the carbon-containing waste liquid (waste liquid obtained after carbon nanotube functionalization) to 6 with ammonia water (NH3 concentration in ammonia water is 5 wt%), and then centrifuging (centrifugation speed is 6000 r / min, centrifugation time is 15 min) to separate the solid and liquid. Take the supernatant to obtain the carbon-containing liquid, and the content of small-sized carbon in the carbon-containing liquid is 0.05 wt%.

[0040] Step 2: Transfer the mixture to the ball mill jar of a planetary ball mill for ball milling: Add grinding balls (by mass, the ratio of grinding balls to mixture is 6:1, i.e., the ball-to-material ratio is 6:1), ball mill at a rotation speed of 500 r / min for 4 h, dry in a vacuum drying oven at 190℃ for 0.5 h, and cool to room temperature to obtain a long afterglow material. The content of small-sized carbon in the long afterglow material is 0.5 wt%.

[0041] Example 2

[0042] A ball milling method for preparing long afterglow materials using carbon-containing waste liquid includes the following steps:

[0043] Step 1: At room temperature, mix the carbon-containing liquid and matrix material (by mass, the ratio of carbon-containing liquid to matrix material is 10:1), and stir until a paste is formed to obtain a mixture. The carbon-containing liquid includes: small-sized carbon, which is graphene fragments (particle size approximately 35 nm), and the matrix material is potassium borate (borate crystals). The method for obtaining the carbon-containing liquid includes: adjusting the pH of the carbon-containing waste liquid (waste liquid obtained after functionalization of graphene powder) to 6 with ammonia water (NH3 concentration in ammonia water is 5 wt%), and then centrifuging (centrifugation speed is 9000 r / min, centrifugation time is 10 min) to separate the solid and liquid, and taking the supernatant to obtain the carbon-containing liquid. The content of small-sized carbon in the carbon-containing liquid is 0.01 wt%.

[0044] Step 2: Transfer the mixture to the ball mill jar of a planetary ball mill for ball milling: Add grinding balls (by mass, the ratio of grinding balls to mixture is 3:1, i.e., the ball-to-material ratio is 3:1), ball mill at a rotation speed of 300 r / min for 6 hours, dry in a vacuum drying oven at 140℃ for 6 hours, and cool to room temperature to obtain a long afterglow material. The content of small-sized carbon in the long afterglow material is 0.1 wt%.

[0045] Example 3

[0046] A ball milling method for preparing long afterglow materials using carbon-containing waste liquid includes the following steps:

[0047] Step 1: At room temperature, mix the carbon-containing liquid and matrix material (by mass, the ratio of carbon-containing liquid to matrix material is 20:1), and stir until a paste is formed to obtain a mixture. The carbon-containing liquid includes small-sized carbon, which is nano-carbon black fragments (particle size approximately 35 nm). The matrix material is sodium borate (borate crystals). The method for obtaining the carbon-containing liquid includes: adjusting the pH of the carbon-containing waste liquid (waste liquid obtained after functionalization of nano-carbon black) to 6 with ammonia water (NH3 concentration in ammonia water is 5 wt%), and then centrifuging (centrifugation speed is 3000 r / min, centrifugation time is 20 min) to separate the solid and liquid. Take the supernatant to obtain the carbon-containing liquid, and the content of small-sized carbon in the carbon-containing liquid is 0.1 wt%.

[0048] Step 2: Transfer the mixture to the ball mill jar of a planetary ball mill for ball milling: Add grinding balls (by mass, the ratio of grinding balls to mixture is 4:1, i.e., the ball-to-material ratio is 4:1), ball mill at a rotation speed of 800 r / min for 6 hours, dry in a vacuum drying oven at 165℃ for 2 hours, and cool to room temperature to obtain a long afterglow material. The content of small-sized carbon in the long afterglow material is 2 wt%.

[0049] Example 4

[0050] A method for preparing a long afterglow material is basically the same as in Example 1, except that "ball milling at a rotation speed of 500 r / min for 4 hours" is replaced with "ball milling at a rotation speed of 500 r / min for 6 hours".

[0051] Example 5

[0052] A method for preparing a long afterglow material is basically the same as in Example 1, except that "ball milling at a rotation speed of 500 r / min for 4 hours" is replaced with "ball milling at a rotation speed of 500 r / min for 8 hours".

[0053] Comparative Example 1

[0054] A comparative material preparation method is basically the same as that in Example 1, except that "transferring the mixture to the grinding jar of a planetary ball mill for ball milling" is replaced with "transferring the mixture to a planetary mixer for mechanical stirring". In Comparative Example 1, the rotation speed of the mechanical stirrer is 500 r / min, the mechanical stirring time is 4 h, and no grinding balls are placed in the mechanical stirrer.

[0055] Comparative Example 2

[0056] A method for preparing a comparative material includes the following steps:

[0057] Step 1: At room temperature, mix commercial toner (acetylene black) and matrix material until homogeneous to obtain a composite. Add deionized water to the composite and stir until a paste is formed to obtain a mixture. The matrix material is boric acid. By mass, the ratio of toner to matrix material is 0.1:20, and the ratio of the mass of matrix material to the volume of deionized water is 20:1. The units of mass are g and the units of volume are L.

[0058] Step 2: Transfer the mixture to the ball mill jar of the planetary ball mill for ball milling: Add grinding balls (ball-to-material ratio of 6:1), ball mill at a rotation speed of 500 r / min for 4 h, dry in a vacuum drying oven at 190℃ for 0.5 h, and cool to room temperature to obtain the comparative material.

[0059] Comparative Example 3

[0060] A comparative material preparation method is basically the same as that in Example 1, except that "ball milling at a rotation speed of 500 r / min for 4 hours" is replaced with "ball milling at a rotation speed of 100 r / min for 4 hours".

[0061] Comparative Example 4

[0062] A comparative material preparation method is basically the same as that in Example 1, except that "ball milling at a rotation speed of 500 r / min for 4 hours" is replaced with "ball milling at a rotation speed of 1000 r / min for 4 hours".

[0063] Comparative Example 5

[0064] A method for preparing a long afterglow material is basically the same as in Example 1, except that "ball milling at a rotation speed of 500 r / min for 4 hours" is replaced with "ball milling at a rotation speed of 500 r / min for 1 hour".

[0065] Comparative Example 6

[0066] A method for preparing a long afterglow material is basically the same as in Example 1, except that "ball milling at a rotation speed of 500 r / min for 4 hours" is replaced with "ball milling at a rotation speed of 500 r / min for 2 hours".

[0067] Comparative Example 7

[0068] A method for preparing a comparative material includes the following steps:

[0069] Step 1: At room temperature, mix the carbon-containing liquid and matrix material (by mass, the ratio of carbon-containing liquid to matrix material is 1:1), and stir until a paste is formed to obtain a mixture. The carbon-containing liquid includes small-sized carbon, which is carbon nanotube fragments (particle size approximately 35 nm). The matrix material is boric acid. The method for obtaining the carbon-containing liquid includes: adjusting the pH of the carbon-containing waste liquid (waste liquid obtained after carbon nanotube functionalization) to 6 with ammonia water (NH3 concentration in ammonia water is 5 wt%), and then centrifuging (centrifugation speed is 6000 r / min, centrifugation time is 15 min) to separate the solid and liquid. Take the supernatant to obtain the carbon-containing liquid, and the content of small-sized carbon in the carbon-containing liquid is 0.05 wt%.

[0070] Step 2: Transfer the mixture to the ball mill jar of the planetary ball mill for ball milling: Add grinding balls (by mass, the ratio of grinding balls to mixture is 6:1, i.e., the ball-to-material ratio is 6:1), ball mill at a rotation speed of 500 r / min for 4 h, dry in a vacuum drying oven at 190℃ for 0.5 h, cool to room temperature, and obtain the comparative material. The content of small-sized carbon in the comparative material is 0.05 wt%.

[0071] Comparative Example 8

[0072] A long afterglow material is the graphene oxide sheet long afterglow material prepared in Example 1 of Publication No. CN119683612A.

[0073] After evaporating the water from the carbon-containing clear liquid in Example 1 of this application, a morphology test was performed, and the results are as follows: Figure 1 As shown. By Figure 1 It can be seen that the particle size of small carbon is about 35nm, which is significantly different from traditional zero-dimensional carbon quantum dots (<10nm).

[0074] The long afterglow characteristics of the materials were tested. The materials were one of the long afterglow materials prepared in Examples 1-5, Comparative Examples 5-6, and Comparative Example 8, and one of the comparative materials prepared in Comparative Examples 1-4 and Comparative Example 7. The test conditions were: ambient temperature of 20-25℃, ultraviolet lamp as the excitation source (excitation wavelength of 365nm), excitation power of 10mW, and excitation time of 2 seconds. After the ultraviolet lamp was turned off, afterglow photographs and afterglow decay curves were collected to obtain the afterglow time. Based on the long afterglow materials of Examples 1 and 2, the following tests were conducted sequentially: Figure 2 and Figure 3 The photograph shown is taken with the UV lamp off, obtained sequentially from the long afterglow materials of Comparative Examples 5 and 8. Figure 4 and Figure 5 The photograph shown is taken with the UV lamp off, based on the long afterglow material of Example 1. Figure 6 The afterglow emission decay curve shown is based on the long afterglow material of Comparative Example 5. Figure 7 The afterglow emission decay curve shown is based on the long afterglow material of Comparative Example 6. Figure 8 The afterglow decay curves shown are based on the long afterglow materials of Example 2 and Comparative Example 8. Figure 9 The afterglow decay curves are shown in Table 1, and the afterglow times of the materials are also shown in Table 1. During a 2-second UV excitation process, the long afterglow materials from Example 2 and Comparative Example 8 were obtained... Figure 10 The phosphorescence spectrum shown is shown.

[0075] Depend on Figures 2-5 It is known that the afterglow emission color of all long-afterglow materials is blue. The long-afterglow materials prepared in Comparative Example 8 and Examples 1-2 are all small-sized carbon-based long-afterglow materials (not the same type of material as carbon quantum dot-based long-afterglow materials). However, Comparative Example 8 uses an electrochemical-assisted method, which is significantly more complex, requires more controllable process parameters, and is more difficult to implement. Furthermore, Figure 2 , Figure 3 and Figure 5 The comparison revealed that the afterglow brightness of E1 and E2 was significantly higher than that of C8 at the same time, indicating that the afterglow intensity of the long afterglow materials obtained in Examples 1 and 2 was higher than that of C8.

[0076] Figure 9 Afterglow luminescence attenuation contrast curve and Figure 3 and Figure 5 Confirmed by each other, from Figure 9 From this, we can see that E2 no longer emits afterglow after 9.2 s, while C8 no longer emits afterglow after 7.4 s; and from... Figure 9 It can be seen that after the UV lamp excitation stops (the horizontal axis represents the UV lamp excitation stopping), the afterglow luminescence intensity at any time of E2 is higher than that of C8.

[0077] Depend on Figure 10 It can be seen that the phosphorescence emitted by the long-afterglow material (E2) obtained in Example 2 and the long-afterglow material (C8) obtained in Comparative Example 8 after excitation is both in the wavelength range of 350 nm to 500 nm, which is blue light. However, the emission peak of E2 is significantly blue-shifted, corresponding to higher photon energy, and the luminescence intensity is better than that of C8. In addition, the full width at half maximum (FWHM) of the long-afterglow material (E2) obtained in Example 2 is narrower than that of the long-afterglow material (C8) obtained in Comparative Example 8, indicating that the blue light of the long-afterglow material obtained in Example 2 is purer and has better monochromaticity, making it a long-afterglow material with superior luminescence performance.

[0078] Table 1

[0079]

[0080] As shown in Table 1, the afterglow times of Examples 4 and 5 are basically the same as those of Example 1. It can be seen that ball milling at a rotation speed of 500 r / min for 4 h is sufficient to fully disperse small carbon particles in the matrix material. Therefore, even if the ball milling time is increased, the degree of dispersion will not be changed (only the energy consumption will increase).

[0081] As shown in Table 1, none of the comparative materials prepared in Comparative Examples 1-4 and Comparative Example 7 exhibited significant long-afterglow characteristics. Specifically, Comparative Example 1, using mechanical stirring, could not disperse small-sized carbon in the matrix material, failing to form a structure that emitted afterglow, resulting in C1 having no obvious afterglow characteristics. Comparative Example 2 used commercial carbon powder with a size of 30-45 nm, which falls into the category of small-sized carbon, but it lacks oxygen-containing functional groups and does not possess luminescent properties. Even if it could be fully dispersed in the matrix material, it could not form a structure that emitted afterglow, resulting in C2 having no afterglow characteristics. This demonstrates that not all small-sized carbon can be used to prepare long-afterglow materials. In Comparative Example 3, the ball mill's rotation speed was too low, failing to fully disperse small-sized carbon in the matrix material, resulting in C3 having no obvious afterglow characteristics. In Comparative Example 4, the ball mill's rotation speed was too high, causing excessive energy applied to the mixture by the grinding balls, which damaged the oxygen-containing functional groups and decomposed the boric acid, preventing the formation of a structure that emitted afterglow, resulting in C4 having no obvious afterglow characteristics. In Comparative Example 7, due to the low content of small-sized carbon, C7 did not exhibit significant afterglow characteristics even when it was fully dispersed in the matrix material.

[0082] As shown in Table 1, the long afterglow materials prepared in Comparative Examples 5 and 6 all exhibit long afterglow characteristics, but their afterglow time is shorter than that of Example 1. This is because the small carbon particles are dispersed in the matrix material to form an afterglow luminescent structure, but the dispersion is insufficient, resulting in shorter afterglow times for C5 and C6.

[0083] In summary, the long afterglow material prepared by the ball milling method of the present invention using carbon-containing waste liquid has significantly enhanced afterglow intensity, higher photon energy (significant blue shift), and significantly extended afterglow time.

[0084] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A ball milling method for preparing long afterglow materials using carbon-containing waste liquid, characterized in that, Includes the following steps: Step 1: Mix the carbon-containing liquid and the matrix material to obtain a mixture. The carbon-containing liquid includes small-sized carbon, which is at least one of carbon nanotube fragments, graphene fragments, and nano-carbon black fragments. The matrix material is boric acid or borate crystals. The method for obtaining the carbon-containing liquid includes: adjusting the pH value of the carbon-containing waste liquid to 5-6, then centrifuging to separate the solid and liquid, and taking the upper clear liquid to obtain the carbon-containing liquid. The centrifugation speed is 3000-9000 r / min, and the centrifugation time is 10-20 min. The method for obtaining carbon-containing waste liquid includes: placing at least one of carbon nanotubes, graphene powder and nano carbon black in nitric acid, stirring under ultrasonic conditions for at least 1 hour, and filtering out the solid to obtain a solution containing carbon-containing waste liquid. Step 2: The mixture is ball-milled and dried to obtain a long afterglow material. The content of small-sized carbon in the long afterglow material is 0.1~2wt%. The ball milling time is at least 4 hours and the rotation speed of the ball mill is 300~800 r / min.

2. The ball milling method for preparing long afterglow materials using carbon-containing waste liquid according to claim 1, characterized in that, In step 1, the particle size of the small carbon particles is 20–50 nm.

3. The ball milling method for preparing long afterglow materials using carbon-containing waste liquid according to claim 1, characterized in that, In step 1, the content of small-sized carbon in the carbon-containing solution is 0.01~0.1wt%.

4. The ball milling method for preparing long afterglow materials using carbon-containing waste liquid according to claim 1, characterized in that, The concentration of HNO3 in nitric acid is 10~15 mol / L. -1 .

5. The ball milling method for preparing long afterglow materials using carbon-containing waste liquid according to claim 1, characterized in that, In step 2, the ball mill uses grinding balls, and the ratio of grinding balls to the mixture is (3~6):1 by mass.

6. The long afterglow material obtained by the ball milling method for preparing long afterglow materials using carbon-containing waste liquid as described in any one of claims 1 to 5.

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