Mesoporous nanosphere based on EPS (Expandable Polystyrene) plastic and preparation method thereof

Abstract

The invention provides an EPS (Expandable Polystyrene) plastic-based mesoporous nanosphere for purifying volatile organic compounds and a preparation method of the EPS plastic-based mesoporous nanosphere.

Description

Technical Field

[0001] The invention relates to the technical field of functional polymer materials, and in particular to mesoporous nanospheres based on EPS plastics for VOC purification and a preparation method thereof. Background Art

[0002] In recent years, volatile organic compounds (VOCs) (e.g., benzene, toluene, etc.) have attracted increasing public attention. VOCs originate from biological or anthropogenic releases, such as chemical industry, agricultural operations, land use, fuel recovery, and pharmaceutical factories. They are considered to be one of the main sources of photochemical reactions in the atmosphere, and can affect the environment and human health even if their concentrations are within the range specified by the government. Adsorption is considered to be one of the most effective technologies for removing VOCs, and polymers as a class of adsorbents have attracted widespread research interest.

[0003] Polystyrene, the main component of EPS plastic, is a common polymer material with good mechanical properties, thermal stability and chemical stability, and is widely used in various fields. However, traditional polystyrene materials have some limitations in their application in adsorption separation, catalytic carriers, environmental remediation, etc., mainly due to their low specific surface area and insufficient porosity. In order to overcome these limitations, researchers proposed the concept of hyper-cross-linked polymers. Hyper-cross-linked polymers are highly cross-linked polymer materials with a large number of pore structures and high specific surface area, which can provide more adsorption sites and reactive centers, thereby exhibiting excellent performance.

[0004] At present, the methods for preparing hyper-crosslinked polymers mainly include solvent method, thermal crosslinking method and surface polymerization method. However, these methods have some problems, such as solvent residue, high temperature conditions and complicated synthesis steps, which limit the large-scale application of hyper-crosslinked polymers. Therefore, a new method for preparing hyper-crosslinked polymer-based mesoporous nanospheres based on polystyrene is needed to overcome the limitations of traditional methods, improve the porosity and specific surface area of ​​the material, and expand its application field. Summary of the invention

[0005] The present invention aims to provide a mesoporous nanosphere based on EPS plastic for VOC purification and a preparation method thereof, so as to overcome the shortcomings of the prior art.

[0006] In a first aspect of the present invention, a mesoporous nanosphere based on EPS plastic for volatile organic compound purification is provided, wherein the mesoporous nanosphere is composed of an EPS plastic-based hyper-crosslinked polymer, wherein the EPS plastic-based hyper-crosslinked polymer has the following structure:

[0007]

[0008] In an embodiment of the first aspect, the molecular weight of the mesoporous nanospheres is 100,000-500,000.

[0009] In the embodiment of the first aspect, the BET specific surface area of ​​the mesoporous nanospheres is 500-1500 m 2 / g, and the average pore size is 5.0858nm.

[0010] In a second aspect of the present invention, a method for preparing mesoporous nanospheres based on EPS plastic for volatile organic compound purification is provided, the preparation method comprising the following steps:

[0011] (1) washing the EPS waste plastic with clean water, and then drying it, then dissolving the dried EPS plastic in an organic solvent, and then adding anhydrous ferric chloride and dimethoxymethane, and under the catalysis of anhydrous ferric chloride, the EPS plastic and dimethoxymethane undergo a substitution reaction to obtain mesoporous nanospheres formed by EPS plastic-based hyper-crosslinked polymers;

[0012] (2) The obtained mesoporous nanospheres are washed and extracted, and then vacuum dried to obtain EPS plastic-based mesoporous nanospheres for volatile organic compound purification.

[0013] In an embodiment of the second aspect, in step (2), the mesoporous nanospheres are washed with acetone, dilute hydrochloric acid and ultrapure water for 1-3 times, respectively, and further purified by Soxhlet extraction with methanol at 80-105° C. for 20-40 hours.

[0014] In an embodiment of the second aspect, in step (1), the organic solvent is 1,2-dichloroethane or tetrahydrofuran or xylene.

[0015] In an embodiment of the second aspect, in step (1), the molar ratio of EPS waste plastic: anhydrous ferric chloride: dimethoxymethane is 1:2-4:10-15.

[0016] Beneficial effects of the present invention:

[0017] The mesoporous nanospheres prepared by the present invention have high specific surface area and porosity, and the adsorption capacity for benzene and toluene can reach 312 mg / g and 341 mg / g respectively. They can be used in the fields of adsorption separation, environmental remediation, etc., and at the same time provide a way of thinking for the high-value utilization of waste foamed plastics, and have broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the structure of mesoporous nanospheres;

[0019] Figure 2 This is the infrared spectrum of EPS plastic and mesoporous nanospheres;

[0020] Figure 3 It is the pore size distribution diagram of porous nanospheres based on NLDFT calculation method;

[0021] Figure 4 This is a scanning electron microscope image of porous nanospheres. DETAILED DESCRIPTION

[0022] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0023] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0024] The term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.

[0025] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more". "Plurality" should be understood as two or more.

[0026] Example 1

[0027] Add 100 mL of water to 1.5 g of EPS waste plastic, stir and wash for 10 minutes, and then place it in a 40 ° C oven to dry for 12 hours. Add the dried plastic to 100 mL of 1,2-dichloroethane, stir to fully dissolve it, and add 6 g of anhydrous ferric chloride and 15 mL of dimethoxymethane. The mixture is reacted at 80 ° C for 20 hours to obtain a solid product. Then, the obtained solid product is washed 3 times with acetone, dilute hydrochloric acid and ultrapure water respectively. Then, the crude product is Soxhlet extracted with methanol at 80 ° C for 20 hours for further purification. Finally, the obtained product is vacuum dried at 100 ° C to obtain a brick-red solid powder.

[0028] Example 2

[0029] Add 100 mL of water to 1.5 g of EPS waste plastic, stir and wash for 10 minutes, and then place it in a 40 ° C oven to dry for 12 hours. Add the dried plastic to 80 mL of tetrahydrofuran, stir to fully dissolve it, then let it stand for 10 minutes, add 6 g of anhydrous ferric chloride and 15 mL of dimethoxymethane. The mixture is reacted at 60 ° C for 30 hours to obtain a solid product. The obtained solid product is washed 3 times with acetone, dilute hydrochloric acid and ultrapure water respectively. Then, the crude product is extracted with methanol at 100 ° C for 24 hours for further purification. Finally, the obtained product is vacuum dried at 100 ° C to obtain a brick-red solid powder.

[0030] Example 3

[0031] Add 100 mL of water to 1.5 g of EPS waste plastic, stir and wash for 10 minutes, and then place it in a 40 ° C oven to dry for 12 hours. Add the dried plastic to 120 mL of xylene, stir to fully dissolve it, then let it stand for 20 minutes, add 6 g of anhydrous ferric chloride and 15 mL of dimethoxymethane. The mixture is reacted at 100 ° C for 10 hours to obtain a solid product. The obtained solid product is washed 3 times with acetone, dilute hydrochloric acid and ultrapure water respectively. Then, the crude product is further purified by Soxhlet extraction with methanol at 105 ° C for 40 hours. Finally, the obtained product is vacuum dried at 100 ° C to obtain a brick-red solid powder.

[0032] Characterization of mesoporous nanospheres

[0033] exist Figure 2 In the infrared spectrum, 700 cm -1 The intensity of the absorption peak at 20° weakened after the reaction, indicating that the proton hydrogen on the benzene ring was replaced, proving that the reaction was successful.

[0034] The BET surface area of ​​the product obtained by isothermal nitrogen adsorption is 500–1500 m 2 / g, for example, the BET specific surface area is 942.3451m 2 / g, from Figure 3 It can be seen that the average pore size of BJH is 5.0858nm; combined Figure 4 The scanning electron microscope image shows that the product is a mesoporous nanosphere with a structure such as Figure 1 shown.

[0035] Test of benzene and toluene adsorption performance of mesoporous nanospheres

[0036] Place a 20 mL glass bottle containing benzene or toluene in a desiccator loaded with mesoporous nanospheres and seal it. Weigh the mesoporous nanospheres and put them back at regular intervals until their weight reaches a stable value. The adsorption capacity of the mesoporous nanospheres for benzene or toluene is measured by the weight change of the mesoporous nanospheres. The adsorption capacity of the material is calculated as follows:

[0037]

[0038] Where: q t Indicates the adsorption capacity of the material within time t, mg / g; m t represents the weight of the mesoporous nanospheres at time t, g; m0 represents the initial weight of the mesoporous nanospheres, g.

[0039] The experimental results show that the adsorption capacity of the mesoporous nanospheres for benzene and toluene is 312 mg / g and 341 mg / g respectively. The mesoporous nanospheres of the present invention have a good adsorption effect on volatile organic compounds such as benzene and toluene, and can be used for the adsorption of volatile organic compounds such as benzene and toluene.

Claims

1. A mesoporous nanosphere based on EPS plastic for purifying volatile organic compounds, wherein the mesoporous nanosphere is composed of an EPS plastic-based hyper-crosslinked polymer, wherein the EPS plastic-based hyper-crosslinked polymer has the following structure:

2. The mesoporous nanosphere according to claim 1, wherein: The molecular weight of the mesoporous nanospheres is 100,000–500,000.

3. The mesoporous nanosphere according to claim 1, wherein: The BET surface area of ​​mesoporous nanospheres is 500–1500 m 2 / g, and the average pore size is 5.0858nm.

4. A method for preparing mesoporous nanospheres based on EPS plastic for volatile organic compound purification, the preparation method comprising the following steps: (1) washing the EPS waste plastic with clean water, and then drying it, then dissolving the dried EPS plastic in an organic solvent, and then adding anhydrous ferric chloride and dimethoxymethane, and under the catalysis of anhydrous ferric chloride, the EPS plastic and dimethoxymethane undergo a substitution reaction to obtain mesoporous nanospheres formed by EPS plastic-based hyper-crosslinked polymers; (2) The obtained mesoporous nanospheres are washed and extracted, and then vacuum dried to obtain EPS plastic-based mesoporous nanospheres for volatile organic compound purification.

5. The method according to claim 4, wherein: In step (2), the mesoporous nanospheres are washed with acetone, dilute hydrochloric acid and ultrapure water for 1-3 times, respectively, and further purified by Soxhlet extraction with methanol at 80-105° C. for 20-40 hours.

6. The method according to claim 4, wherein: In step (1), the organic solvent is 1,2-dichloroethane or tetrahydrofuran or xylene.

7. The method according to claim 4, wherein: In step (1), the molar ratio of EPS waste plastic: anhydrous ferric chloride: dimethoxymethane is 1:2-4:10-15.

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