Method for rapidly synthesizing lignin carbon dots through electron beam irradiation
Electron beam irradiation facilitates rapid and efficient synthesis of lignin carbon dots at room temperature, addressing the inefficiencies of traditional methods by providing a scalable and environmentally friendly process with adjustable fluorescence.
Patent Information
- Application Number
- CN202411242709.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2024-12-10
AI Technical Summary
Existing methods for synthesizing carbon quantum dots (CDs) are energy-intensive and environmentally inefficient, requiring long reaction times and high temperatures, limiting their scalability and environmental impact.
A method utilizing electron beam irradiation to rapidly depolymerize and carbonize lignin at room temperature, enabling instantaneous synthesis of lignin-based carbon dots through high-energy electron beam irradiation, allowing adjustment of fluorescence emission intensity by varying the radiation dose.
Enables rapid, energy-efficient, and scalable synthesis of lignin carbon dots at room temperature without external temperature or pressure increases, with adjustable fluorescent properties.
Smart Images
Figure HDA0005029762850000011 
Figure HDA0005029762850000012
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of carbon dot synthesis, and in particular relates to a method for rapidly synthesizing lignin carbon dots by electron beam irradiation. Background Art
[0002] Carbon quantum dots (CDs), also known as carbon dots, are composed of ultrafine, dispersed, quasi-spherical carbon nanoparticles. They are a type of zero-dimensional carbon nanomaterial with significant fluorescent properties. CDs have a wide range of applications in various fields due to their small size, good fluorescent properties, and good biocompatibility. Up to now, CDs are mostly synthesized by hydrothermal method, which usually requires a reaction time of more than 24 hours, high temperature, closed system and high pressure. Considering large-scale production, traditional hydrothermal synthesis of CDs is quite energy-consuming. Although in the past decade, scientists have also been committed to opening up new ways to synthesize CDs, such as laser ablation, chemical oxidation, electrochemical oxidation, etc., these methods are still limited in their ability to improve environmental effects and synthesis efficiency. Finding CDs synthesis methods with good environmental benefits and high synthesis efficiency (with advantages in saving time and energy) is still the research goal in this field.
[0003] Lignin has a high carbon content and contains abundant aromatic rings and reactive sites, such as aliphatic and aromatic hydroxyl groups and carboxyl groups, which makes lignin have the potential to depolymerize and carbonize to form carbon nanoparticles. In the hydrothermal reaction, lignin CDs mainly involve the depolymerization of lignin macromolecules and the repolymerization of small molecules. The hydrogen ions dissociated from water first attack the ether bonds of lignin to form a large number of lignin fragments, which are composed of hydrophobic aromatic structures and hydrophilic hydroxyl groups. In addition, these fragments condense to form primary clusters, which are then converted into primary aromatic clusters through dehydration, polymerization and condensation reactions. As the reaction time increases, these primary aromatic clusters undergo rapid π-π bond accumulation, sp 2 Hybridization increases and aromatic polymerization forms lignin CDs. Based on the above discussion, the depolymerization of lignin macromolecules is the key step in the formation of lignin CDs, and the degree of depolymerization is closely related to the molecular weight of lignin. Electron beam (EB) irradiation is a unique energy source that is widely used in many fields of basic research and industrial production. Due to the high energy of EB, they can produce a radiation etching effect on solid materials, causing the skeleton of complex compounds to collapse, bonds to break, depolymerize to form small molecular fragments, and even completely fragment when the absorbed dose is high enough.
[0004] There is no report on the synthesis of CDs by EB irradiation. Based on this, the present invention provides a method for synthesizing lignin-based CDs by EB irradiation, rapid depolymerization and carbonization of lignin at room temperature. Summary of the invention
[0005] The technical problem solved by the present invention is to provide a method for rapidly synthesizing lignin carbon dots by electron beam irradiation. The purpose of the present invention is to provide a feasible method for synthesizing lignin-based carbon dots by rapidly depolymerizing and carbonizing lignin by EB irradiation at room temperature. The mechanism of action of the method is to accelerate the depolymerization and carbonization of lignin by high-energy electron beam irradiation, so that lignin carbon dots are synthesized instantly at room temperature. The method is not only a universal method for large-scale production of lignin carbon dots with simple operation, but also can adjust the fluorescence emission intensity of the synthesized CDs by adjusting the radiation dose.
[0006] In order to achieve the above object, the technical solution adopted by the present invention is:
[0007] A method for rapidly synthesizing lignin carbon dots by electron beam irradiation comprises the following steps:
[0008] Step 1): flatten the lignin powder and irradiate the lignin powder with an electron beam;
[0009] Step 2): dissolving the irradiated lignin powder in step 1) in ultrapure water to form a lignin solution and stirring the solution evenly;
[0010] Step 3): After centrifuging the uniformly stirred lignin solution in step 2), the supernatant is filtered with a filter membrane, and then the filtrate is transferred to a dialysis bag for dialysis, and finally the solution in the dialysis bag is collected and freeze-dried to obtain lignin carbon dots CDs.
[0011] In the above step 1), the electron beam irradiation dose is 50 to 400 kGy.
[0012] In the above step 2), the dissolution ratio of the irradiated lignin powder to ultrapure water is 3:250 by weight.
[0013] In the above step 2), the ultrapure water is distilled water.
[0014] The uniform solution in the above step 3) was centrifuged at 10000 rpm for 30 min, the supernatant was filtered with a 0.22 μm filter membrane, and then the filtrate was transferred to a dialysis bag with a molecular weight of 3500 Da and dialyzed for more than 24 hours.
[0015] Once the irradiated lignin powder in the above steps 2) and 3) is dissolved in ultrapure water and stirred evenly, it is directly centrifuged, filtered and dialyzed without further reaction time.
[0016] The advantages of the present invention compared with the prior art are:
[0017] This scheme provides a feasible method for synthesizing lignin-based CDs by EB irradiation of lignin, rapid depolymerization and carbonization at room temperature. No external temperature and pressure increase conditions are required during the synthesis process, achieving room temperature synthesis and rapid synthesis. The mechanism of action of this invention is to quickly interrupt the bonding of lignin molecules through high-energy electron beam irradiation, accelerate the cracking and carbonization of lignin, and achieve instantaneous synthesis of CDs at room temperature. The fluorescent properties of CDs synthesized by this method can be achieved by changing the irradiation dose. This method is simple and easy to operate, and has good universality. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a fluorescence intensity diagram of lignin carbon dots CDs prepared by 50 kGy irradiation in Example 1 of the present invention;
[0019] Figure 2 This is a fluorescence intensity diagram of lignin carbon dots CDs prepared by 200 kGy irradiation in Example 2 of the present invention. DETAILED DESCRIPTION
[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0021] See also Figure 1-2 , details of the embodiments of the present invention.
[0022] A method for rapidly synthesizing lignin carbon dots by electron beam irradiation comprises the following steps:
[0023] Step 1): flatten the lignin powder and irradiate the lignin powder with an electron beam;
[0024] Preferably, the electron beam irradiation dose is 50 to 400 kGy.
[0025] The lignin powder is flattened using the commonly used method in the irradiation field, and the thickness of the lignin powder after flattening is about 1.5 cm.
[0026] Step 2): dissolving the irradiated lignin powder in step 1) in ultrapure water to form a lignin solution and stirring the solution evenly;
[0027] Wherein, the dissolution ratio of the irradiated lignin powder and ultrapure water is 3:250 by weight.
[0028] Preferably, the ultrapure water is distilled water.
[0029] Step 3): After centrifuging the uniformly stirred lignin solution in step 2), the supernatant is filtered with a filter membrane, and then the filtrate is transferred to a dialysis bag for dialysis, and finally the solution in the dialysis bag is collected and freeze-dried to obtain lignin carbon dots CDs;
[0030] In this step, the uniform lignin solution was centrifuged at 10,000 rpm for 30 min, the supernatant was filtered with a 0.22 μm filter membrane, and then the filtrate was transferred to a dialysis bag with a molecular weight of 3,500 Da and dialyzed for more than 24 h.
[0031] Once the irradiated lignin powder in the above steps 2) and 3) is dissolved in ultrapure water and stirred evenly, it is directly centrifuged, filtered and dialyzed without further reaction time.
[0032] Embodiment 1:
[0033] A method for rapidly synthesizing lignin carbon dots by electron beam irradiation is prepared by the following steps:
[0034] 1. Weigh the lignin solid powder, flatten the lignin powder, and irradiate it with an electron beam. The electron beam irradiation dose is 50 kGy.
[0035] 2. Dissolve 1.2 g of the irradiated lignin powder in 100 mL of distilled water to form a lignin solution, and stir thoroughly;
[0036] 3. The stirred lignin solution was centrifuged at 10000 rpm for 30 min, and the supernatant was filtered with a 0.22 μm filter membrane. The filtrate was then transferred to a dialysis bag with a molecular weight of 3500 Da and dialyzed for 24 h. The solution in the dialysis bag was collected and freeze-dried to obtain lignin carbon dots CDs. The synthesized lignin CDs were excited at 230 nm and emitted in the range of 450-470 nm. The fluorescence intensity reached about 1100 a.u., such as Figure 1 shown.
[0037] Embodiment 2:
[0038] A method for rapidly synthesizing lignin carbon dots by electron beam irradiation is prepared by the following steps:
[0039] 1. Weigh the lignin solid powder, flatten it, and irradiate it with electron beam at a dose of 200 kGy.
[0040] 2. Dissolve 1.2 g of the irradiated lignin powder in 100 mL of distilled water to form a lignin solution, and stir thoroughly;
[0041] 3. The stirred lignin solution was centrifuged at 10000 rpm for 30 min, and the supernatant was filtered with a 0.22 μm filter membrane. The filtrate was then transferred to a dialysis bag with a molecular weight of 3500 Da and dialyzed for 24 h. The solution in the dialysis bag was collected and freeze-dried to obtain lignin carbon dots CDs. The synthesized lignin carbon dots CDs were excited at 230 nm and emitted in the range of 450-470 nm. The fluorescence intensity reached about 1300 a.u., such as Figure 2 shown.
[0042] It can be seen from the above embodiments that the present invention provides a method for rapid synthesis of lignin carbon dots by electron beam irradiation, which uses electron beam irradiation to quickly interrupt the bonding of lignin molecules, accelerate the cracking and carbonization of lignin, and achieve instantaneous synthesis of CDs at room temperature; no external temperature and pressure increase conditions are required during the synthesis process, and room temperature synthesis and rapid synthesis are achieved. The fluorescent properties of CDs synthesized by this method can be achieved by changing the irradiation dose. The method is simple and easy to operate, and has good universality.
[0043] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.
[0044] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.
Claims
1. A method for rapidly synthesizing lignin carbon dots by electron beam irradiation, characterized in that: The steps include: Step 1): flatten the lignin powder and irradiate the lignin powder with an electron beam; Step 2): dissolving the irradiated lignin powder in step 1) in ultrapure water to form a lignin solution and stirring the solution evenly; Step 3): After centrifuging the uniformly stirred lignin solution in step 2), the supernatant is filtered with a filter membrane, and then the filtrate is transferred to a dialysis bag for dialysis, and finally the solution in the dialysis bag is collected and freeze-dried to obtain lignin carbon dots CDs.
2. The method for rapid synthesis of lignin carbon dots by electron beam irradiation according to claim 1, characterized in that: In the above step 1), the electron beam irradiation dose is 50 to 400 kGy.
3. The method for rapid synthesis of lignin carbon dots by electron beam irradiation according to claim 1, characterized in that: In the above step 2), the dissolution ratio of the irradiated lignin powder to ultrapure water is 3:250 by weight.
4. The method for rapid synthesis of lignin carbon dots by electron beam irradiation according to claim 1, characterized in that: In the above step 2), the ultrapure water is distilled water.
5. The method for rapid synthesis of lignin carbon dots by electron beam irradiation according to claim 1, characterized in that: The uniform lignin solution in the above step 3) was centrifuged at 10000 rpm for 30 min, the supernatant was filtered with a 0.22 μm filter membrane, and then the filtrate was transferred to a dialysis bag with a molecular weight of 3500 Da and dialyzed for more than 24 h.
6. The method for rapid synthesis of lignin carbon dots by electron beam irradiation according to claim 1, characterized in that: Once the irradiated lignin powder in the above steps 2) and 3) is dissolved in ultrapure water and stirred evenly, it is directly centrifuged, filtered and dialyzed without further reaction time.