Method for pyrolyzing waste polypropylene plastic into carbonylated carbon nanomaterial and application of carbonylated carbon nanomaterial

Abstract

The invention discloses a method for pyrolyzing waste polypropylene plastic into a carbonylated carbon nanomaterial and application of the carbonylated carbon nanomaterial, and belongs to the technical field of solid waste resource utilization. The method comprises the following steps: by taking waste polypropylene plastic as a raw material and nickel sesquioxide as a catalyst, pyrolyzing a polypropylene molecular chain at 450-600 DEG C by adopting a low-temperature pyrolysis technology, and finally converting the waste polypropylene plastic into the carbonylated carbon nanomaterial through catalytic pyrolysis, cyclization and aromatization reaction and dehydrogenation reaction. According to the method disclosed by the invention, the waste plastic is converted into the carbon nanomaterial with high additional value, so that the problem of pollution caused by the waste plastic is effectively solved, a new way is provided for recycling the waste plastic, and carbon emission reduction is favorably realized. The method saves energy, reduces emission of harmful gas, is more environment-friendly, is simple and easy to control in the pyrolysis process, and is beneficial to large-scale production.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste resource utilization, in particular to a method and application of pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials. Background Art

[0002] Plastic polymers account for a considerable portion of the waste generated worldwide. Although plastic polymers only account for 5-15% of the mass of municipal solid waste, they account for 20-30% of the volume of municipal solid waste. Globally, about 42% of plastics are used for packaging, most of which are non-recyclable and disposable consumables with a short service life of less than 12 months. At present, the total amount of waste plastics in the world has reached 6.3 billion tons, and about 90% of waste plastics are landfilled or accumulated in the natural environment. They are difficult to biodegrade, and they migrate and transform through the atmosphere, water bodies, and soil to form pollution superposition, causing serious complex pollution such as visual pollution, soil pollution, and water pollution, which brings lasting harm to the ecological environment. Therefore, how to remove and utilize waste plastics has become an urgent problem to be solved.

[0003] At present, the main ways to recycle and treat waste plastics are landfill, incineration and recycling. Although the above methods have good treatment effects on waste plastics, they still have their own inherent disadvantages. The landfill method not only fails to make resource utilization of waste plastics, but also the ground after landfill is soft, and harmful substances such as bacteria and viruses in the garbage can easily penetrate into the ground, polluting groundwater and endangering the surrounding environment; the incineration process will produce a large amount of harmful gases, which will cause harm to the environment and human body; the recycling method has the disadvantages of high recycling cost and low utilization efficiency.

[0004] Carbon nano-reinforced plastics are adopted by the sports and leisure industries and have been successful in products such as bicycles, golf clubs, fishing rods and tennis rackets. This not only reduces the weight of sports equipment, but also improves the athletic level of athletes. Carbon nanocomposites have the advantages of light weight, high strength and stiffness, which can reduce the weight of transportation vehicles, improve the fuel efficiency of transportation vehicles, and reduce the emission of exhaust gases such as carbon dioxide. Carbon nano is the most ideal material for modern transportation to achieve lightweight. So far, carbon nano has been widely used in the fuselage of large civil airliners. Carbon nano-reinforced composites are used in the warheads and engine casings of strategic missiles, which can greatly reduce the weight of missiles and increase the range of missiles. In addition, carbon nano is used for the reinforcement and repair of building structures, which can improve the seismic resistance and durability of building structures. And due to good biocompatibility and long service life, in the field of medical devices, carbon nano materials can be used to manufacture artificial bones, prostheses, etc. In the energy industry, carbon nano can be used to manufacture wind turbine blades, solar panels, etc. to improve energy efficiency.

[0005] Waste plastics usually have the characteristics of high carbon content and few impurities. Using carbon compensation provided by waste plastic resource utilization to offset carbon emissions is an important way to achieve "pollution reduction and carbon reduction" or even carbon neutrality. In recent years, a lot of research has been carried out around the resource utilization of waste plastics and the preparation of functional carbon materials using waste plastics as raw materials. Carbonyl carbon nanomaterials prepared from waste plastics include carbon nanotubes, carbon nanowires, activated carbon and graphene-based materials, which not only have the advantages of conventional carbon nanomaterials, but also have unique surface properties and functional characteristics. The surface of waste plastic-derived carbon nanomaterials contains functional units such as oxygen-rich functional groups (such as carboxyl, hydroxyl, phenolic hydroxyl, quinone, etc.), heterocyclic nitrogen, surface defect sites and persistent free radicals. Therefore, converting waste plastics into high-value-added carbon materials not only effectively solves the problem of waste plastic pollution, but also provides a new way for the recycling and reuse of waste plastics, which helps to achieve carbon emission reduction. Summary of the invention

[0006] The purpose of the present invention is to provide a method and application of pyrolysis of waste polypropylene plastics into carbonylation carbon nanomaterials. Low-temperature pyrolysis technology is used to break the polypropylene molecular chain under low-temperature conditions, and benzene and aromatic hydrocarbons containing six-membered rings are generated through free radical reaction, polymerization reaction, dehydrogenation reaction and cyclization reaction, which are finally deposited to form carbonylation carbon nanomaterials.

[0007] To achieve the above object, the present invention provides a method for pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials, comprising the following steps: S1, grinding and mixing waste polypropylene plastic and nickel trioxide in a mortar; S2, pyrolyzing the uniform mixture in S1 to obtain a carbonyl carbon nanomaterial mixed with nickel trioxide; S3, placing the carbonyl carbon nanomaterial containing nickel trioxide prepared in S2 in hydrochloric acid for reflux; S4, filtering, washing and drying the carbonyl carbon nanomaterial after refluxing in S3 to obtain the carbonyl carbon nanomaterial.

[0008] Preferably, in step S1, the mass ratio of waste polypropylene plastic to nickel trioxide is (10-20): (0.5-1).

[0009] Preferably, in step S2, pyrolysis is carried out in a tubular furnace; the pyrolysis environment is an argon atmosphere; the pyrolysis calcination temperature is 450-600°C; the heating rate of the pyrolysis process is 5-10°C / min; and the pyrolysis time is 1-3 hours.

[0010] Preferably, in step S3, the concentration of hydrochloric acid used for reflux is 1-3 mol / L, and the reflux time is 12-24 hours.

[0011] Preferably, in step S4, the refluxed carbon nanomaterial is washed three times with deionized water and ethanol respectively under the action of suction filtration, and the washed sample is placed in an oven at 60° C. to dry overnight.

[0012] The present invention also provides carbonyl carbon nanomaterials prepared by the preparation method for use in the fields of electronics, semiconductors, energy, environmental protection, composite materials and aerospace.

[0013] Carbonylation carbon nanomaterials are formed by random breaking of polypropylene macromolecule chains under heat to generate smaller molecular fragments. As the temperature rises, the small molecular fragments undergo cyclization reactions to form carbonyl-rich ring structures. Nickel trioxide can not only reduce the pyrolysis temperature and increase the yield of carbon nanoparticles from polypropylene pyrolysis, but also improve the structure of carbon materials.

[0014] Therefore, the present invention discloses a method and application of pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials, which has the following advantages: (1) The present invention can efficiently utilize the abundant carbon resources in waste plastics and effectively convert the carbon elements in waste plastics into nano-carbon materials, such as nano-carbon fibers, nano-carbon balls, etc. This efficient conversion not only improves the utilization rate of resources, but also gives waste plastics new value. In addition, the cost of obtaining raw materials is low, which reduces the production cost of the product - carbonylation carbon nanomaterials; (2) The method of the present invention requires less pyrolysis heat than conventional methods, saves energy, reduces the emission of harmful gases, is more environmentally friendly, and the pyrolysis process is simple and easy to control, which is conducive to large-scale production; (3) The carbonyl carbon nanomaterial prepared by the present invention can fully contact and react with persulfate. The carbonyl group on the surface of the carbonyl carbon nanomaterial can interact with the persulfate, resulting in the breakage of the peroxy bond in the persulfate ion, and the generation of singlet oxygen with strong oxidizing properties. At the same time, the singlet oxygen has extremely strong oxidizing ability and can attack the chemical bonds in the organic pollutant molecules, causing them to break and convert into small molecules, thereby accelerating the degradation rate of the organic pollutants. (4) The carbonyl carbon nanomaterial prepared by the present invention has a high specific surface area, excellent electrical conductivity and optical properties.

[0015] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The XRD spectrum of the carbonyl carbon nanomaterial prepared in Example 1 of the present invention; Figure 2 This is a SEM image of the carbonyl carbon nanomaterial prepared in Example 1 of the present invention; Figure 3This is a BET diagram of the carbonyl carbon nanomaterial prepared in Example 1 of the present invention; Figure 4 This is the Mott-Schottky diagram of the carbonyl carbon nanomaterial prepared in Example 1 of the present invention; Figure 5 This is the FTIR image of the carbonyl carbon nanomaterial prepared in Example 1 of the present invention; Figure 6 This is the ultraviolet diffuse reflectance image of the carbonyl carbon nanomaterial prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0018] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0019] In addition, it should be understood that although this specification is described according to the implementation modes, not every implementation mode includes 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. These other implementation modes are also covered within the protection scope of the present invention.

[0020] The method for pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials according to the present invention is further described below in conjunction with examples.

[0021] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0022] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0023] Unless otherwise specified in the present invention, the reagents, instruments, and equipment used are those commonly used by technicians in this field.

[0024] Example 1 3 g of waste polypropylene plastic and 0.15 g of nickel trioxide were uniformly mixed in a porcelain boat, and the porcelain boat was placed in a tube furnace in an argon atmosphere for pyrolysis. The calcination temperature was 450°C, the heating rate of the pyrolysis process was 5°C / min, and the pyrolysis time was 1 hour. The pyrolyzed material was refluxed in 1 mol / L hydrochloric acid for 12 hours, and finally washed three times with deionized water and ethanol, and dried in an oven at 60°C for 12 hours to obtain carbonyl carbon nanomaterials. Figure 1 This is the XRD diagram of the carbonylation carbon nanomaterial of the present invention. As can be seen from the image, there are two obvious peaks in the spectrum, marked as (002) and (100), respectively, indicating that the carbonylation carbon nanomaterial has the characteristic peaks of graphite interlayer spacing and carbon nanotubes, and has a graphite layered structure. Figure 2 This is a SEM image of the carbonyl carbon nanomaterial of the present invention. As can be seen from the image, the present invention successfully prepared the carbonyl carbon nanomaterial, which is spherical, has uniform particle distribution, and has a multi-scale structure. Figure 3 The BET diagram of the carbonylation carbon nanomaterial of the present invention shows that the surface area of ​​the carbonylation carbon nanomaterial is 190.16 m 2 / g, has a higher specific surface area. Figure 4 This is the Mott-Schottky diagram of the carbonyl carbon nanomaterial of the present invention. It can be seen from the diagram that the carbonyl carbon material has good electrical conductivity. Figure 5 The FTIR image of the carbonylation carbon nanomaterial of the present invention shows that the prepared carbon nanomaterial has a wavelength of 1633 cm -1 There is a carbonyl fluctuation peak, which means it is a carbon nanomaterial containing carbonyl. Figure 6 This is the ultraviolet diffuse reflection diagram of the carbonyl carbon nanomaterial of the present invention. It can be seen from the figure that there are corresponding signals in the 200-1000nm band, so the carbonyl carbon material has good optical properties.

[0025] Example 2 6 g of waste polypropylene plastic and 0.6 g of nickel trioxide were uniformly mixed in a porcelain boat, and the porcelain boat was placed in a tube furnace in an argon atmosphere for pyrolysis. The calcination temperature was 500°C, the heating rate of the pyrolysis process was 5°C / min, and the pyrolysis time was 2 hours. The pyrolyzed material was refluxed in 1 mol / L hydrochloric acid for 12 hours, and finally washed three times with deionized water and ethanol, and dried in an oven at 60°C for 12 hours to obtain carbonyl carbon nanomaterials.

[0026] Example 3 9 g of waste polypropylene plastic and 0.63 g of nickel trioxide were uniformly mixed in a porcelain boat, and the porcelain boat was placed in a tube furnace in an argon atmosphere for pyrolysis. The calcination temperature was 550°C, the heating rate of the pyrolysis process was 8°C / min, and the pyrolysis time was 3 hours. The pyrolyzed material was refluxed in 2 mol / L hydrochloric acid for 24 hours, and finally washed three times with deionized water and ethanol, and dried in an oven at 60°C for 24 hours to obtain carbonyl carbon nanomaterials.

[0027] Example 4 12 g of waste polypropylene plastic and 1 g of nickel trioxide were uniformly mixed in a porcelain boat, and the porcelain boat was placed in a tubular furnace in an argon atmosphere for pyrolysis. The calcination temperature was 600°C, the heating rate program of the pyrolysis process was: 10°C / min heating, and the pyrolysis time was 3 hours. The pyrolyzed material was refluxed in 3 mol / L hydrochloric acid for 24 hours, and finally washed three times with deionized water and ethanol, and dried in an oven at 60°C for 24 hours to obtain carbonyl carbon nanomaterials.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials, characterized in that: The following steps are involved: S1, grinding and mixing waste polypropylene plastic and nickel trioxide in a mortar; S2, pyrolyzing the uniform mixture in S1 to obtain a carbonyl carbon nanomaterial mixed with nickel trioxide; S3, placing the carbonyl carbon nanomaterial containing nickel trioxide prepared in S2 in hydrochloric acid for reflux; S4, filtering, washing and drying the carbonyl carbon nanomaterial after refluxing in S3 to obtain the carbonyl carbon nanomaterial.

2. The method for pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials according to claim 1, characterized in that: In step S1, the mass ratio of waste polypropylene plastic to nickel trioxide is (10-20): (0.5-1).

3. The method for pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials according to claim 1, characterized in that: In step S2, pyrolysis is carried out in a tubular furnace; the pyrolysis environment is an argon atmosphere; the pyrolysis calcination temperature is 450-600°C; the heating rate of the pyrolysis process is 5-10°C / min; and the pyrolysis time is 1-3 hours.

4. The method for pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials according to claim 1, characterized in that: In step S3, the concentration of hydrochloric acid used for reflux is 1-3 mol / L, and the reflux time is 12-24 hours.

5. The method for pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials according to claim 1, characterized in that: In step S4, the refluxed carbon nanomaterials are washed three times with deionized water and ethanol respectively under the action of suction filtration, and the washed samples are placed in an oven at 60° C. to dry overnight.

6. An application of the method for pyrolyzing waste polypropylene plastics into carbonylation carbon nanomaterials as claimed in any one of claims 1 to 5, characterized in that: The carbonyl carbon nanomaterial prepared by the method is used in the fields of electronics, semiconductors, energy, environmental protection, composite materials and aerospace.

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