Colored micro-nano plastic product as well as preparation method and application thereof

Abstract

The invention relates to a colored micro-nano plastic product as well as a preparation method and application thereof. The colored micro-nano plastic product is prepared by mixing a polymer matrix and an inorganic pigment according to a mass ratio of (2-20): 1, the polymer matrix is polypropylene or polystyrene or polyethylene; the inorganic pigment is an iron oxide pigment; the preparation method comprises the following steps: S1, melt blending; s2, carrying out post-treatment; the application refers to application in catalytic degradation of TMB or organic pollutants and catalytic self-degradation of colored micro-nano plastic. According to the colored micro-nano plastic product, the metal oxide pigment with enzyme-like activity is introduced and is different from a traditional Fenton or nano catalytic system, a catalytic center comes from a pigment in plastic, additional metal does not need to be added, the plastic becomes a catalyst carrier, the obtained colored micro-nano plastic product can remarkably catalyze H2O2 to generate ROS, the peroxidase-like activity is shown, and the color of the colored micro-nano plastic product is improved. And the additional function of catalytic self-degradation of coexisting pollutants such as organic pollutant antibiotic tetracycline under certain conditions can be realized.

Description

Technical Field

[0001] This invention relates to the field of micro-nanoplastics technology, specifically to a colored micro-nanoplastics product, its preparation method, and its application. Background Technology

[0002] Microplastics, characterized by their small particle size, high mobility, and high chemical stability, are difficult to degrade in the natural environment and can remain in environmental media such as water, soil, and atmosphere for extended periods. The widespread distribution of microplastics in the environment and their extremely long degradation cycle make them highly susceptible to entering the food chain and ultimately accumulating in organisms, thus posing a potential threat to ecosystem stability and human health. Therefore, developing efficient microplastic degradation strategies is an important topic in current environmental science research.

[0003] In recent years, significant progress has been made in microplastic degradation technology, mainly including four degradation pathways: biodegradation, photodegradation, chemical degradation, and thermal degradation. Biodegradation methods involve bacterial degradation, fungal degradation, enzymatic biodegradation, and combined biodegradation. Photodegradation refers to the molecular breakage and cross-linking reactions of polymers caused by light irradiation, forming new non-polymer structures, oxidized polymers, hydrocarbon polymers, and a series of low molecular weight substances and oxidation products, including solar degradation in the natural environment and photocatalytic degradation. Chemical degradation includes hydrolysis and oxidative degradation, with advanced oxidation processes being an effective chemical oxidative degradation technology. Thermal degradation can be used as a pretreatment to enhance the biodegradability of polymers, and the heat released during thermal degradation can also provide energy for the oxidation of carbon in the polymer backbone.

[0004] Recent studies have found that inorganic pigments in plastics can not only affect their physicochemical properties but also alter their degradation behavior under specific conditions. Existing research indicates that the color of plastics affects their light absorption characteristics, thereby altering their photo-aging degradation rate. The photodegradation rate of colored microplastics is largely influenced by the type and content of pigments on their surface. For example, some dark-colored plastics may degrade faster due to absorbing more ultraviolet energy, while some microplastics containing stable inorganic pigments may exhibit higher durability. Therefore, iron-based pigments, as important inorganic pigments, are not only widely used for coloring plastic products but may also influence the degradation behavior of plastics. Iron-based peroxidase materials have attracted widespread attention due to their potential applications in environmental pollution control, biosensing, and catalytic conversion. Current research shows that Fe3O4-based peroxidases can catalyze the degradation of microplastics by H2O2 under high-temperature hydrothermal conditions, exhibiting a significant catalytic degradation effect. Therefore, microplastics colored with iron-based pigments may also have the potential to promote their own degradation through a similar mechanism.

[0005] Existing technologies for microplastic degradation and functionalized plastics still have the following shortcomings: 1. Strong dependence on additional catalysts: Most chemical degradation methods require the addition of Fe to the system. 2+ Mn 2+ 1. Plasma catalysts present problems such as high cost, catalyst loss, and secondary pollution. 2. Complex material preparation hinders application: Existing functionalized plastics typically require the introduction of special monomers, nanostructure construction, and complex chemical modifications, making them difficult to integrate with conventional large-scale industrial processing techniques such as injection molding and extrusion. 3. Complex monitoring of microplastic degradation processes: Traditional degradation methods struggle to gradually determine whether the required degradation conditions have been met, easily leading to over-oxidation or energy waste. 4. Plastics themselves cannot participate in catalytic degradation: Most plastics only act as pollutant carriers, lacking catalytic activity and not participating in their own degradation.

[0006] This technology takes iron-based pigment-colored microplastics as an example, and provides a colored plastic product and its application that is prepared by conventional injection molding process, has peroxidase-like catalytic activity, controllable self-degradation ability and visual degradation indication function. It provides a new idea for the resource-based treatment of plastic waste and provides a scientific basis for plastic pollution control. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a colored micro / nanoplastics product, prepared by mixing a polymer matrix and inorganic pigments in a mass ratio of 2 to 20:1; wherein the polymer matrix is ​​polypropylene, polystyrene, or polyethylene.

[0008] Furthermore, the inorganic pigment is an iron oxide pigment; The iron oxide pigments used are commercially available, specifically Bayer. Ⓡ 4610 Light Brown Iron Oxide Pigment; Bayer Ⓡ 660 Dark Brown Iron Oxide Pigment; 728 Iron Oxide Black; Bayer Ⓡ 4686 Dark brown iron oxide pigment; Furthermore, the inorganic pigment is an inorganic pigment containing an Fe-based layered bimetallic structure; the Fe-based layered bimetallic structure is composed of Fe... 3+ With Mg 2+ Ni 2+ Zn 2+ Co 2+ Cu 2+ It is prepared from any of the following methods; The preparation method of the Fe-based bimetallic structure inorganic pigment is as follows: the Fe-based bimetallic structure is placed in a tube furnace, heated to 290~310℃ under air atmosphere and heating rate of 5℃ / min and held for 25~35min, then heated to 500~600℃ at heating rate of 3~5℃ / min and calcined for 2~4h, then heated to 1100~1400℃ at heating rate of 5℃ / min and calcined for 2~10h, cooled to 22~30℃ in the furnace, and ball-milled to 80~100 mesh at 100~200rpm to obtain the Fe-based bimetallic structure inorganic pigment. Note: Inorganic pigments prepared by solid-state reaction exhibit excellent weather resistance, heat resistance, and chemical stability, making them suitable for plastic coloring. Gentle ball milling avoids excessive mechanical damage to the layered structure, maximizing the preservation of the layered characteristics of the Fe-based bimetallic structure, the anchoring effect of metal active sites, and the electronic synergistic effect, ensuring optimal performance in microplastic degradation and catalytic applications. Appropriate interlayer spacing in the Fe-based bimetallic structure facilitates the generation and diffusion of reactive oxygen species (ROS). Inorganic pigments containing transition metals can not only be used for coloring but also serve as solid-state peroxidase catalytic centers, directly imparting catalytic activity to injection-molded plastics without the need for additional catalysts.

[0009] Furthermore, the preparation method of the Fe-based bimetallic structure is as follows: A 0.1–0.2 mol / L divalent metal salt solution and a 0.1–0.2 mol / L Fe(NO3)3 solution were mixed at a molar ratio of 2–4:1 and dissolved in 100–500 mL of deionized water to obtain a Fe-based metal salt mixed solution. This Fe-based metal salt mixed solution was then simultaneously added dropwise to a reaction vessel at a volume ratio of 1:1 to a 0.1–0.5 mol / L NaOH solution at a dropping rate of 2–3 drops / s, with the pH controlled at 9–10. The mixture was stirred continuously at 60–80 °C for 2–6 h. The precipitate was then transferred to a high-pressure reactor and hydrothermally reacted at 100–150 °C for 12–24 h. Finally, the mixture was subjected to a high-pressure reactor at 3000–6000 °C. Centrifuge at rpm for 5-10 min, collect the precipitate, wash with deionized water and anhydrous ethanol alternately 3-5 times until the pH of the filtrate is 6-7, each washing time is 10-15 min, and finally dry in a vacuum drying oven at 60-80℃ for 12-24 h to obtain Fe base layer bimetallic structure. Explanation: By introducing a second metal (such as Co, Ni, Mn, etc.), a strong electronic synergistic effect is generated between the two metal ions in the Fe-layered bimetallic structure. Taking the Fe-Co layered bimetallic structure as an example, Co... 3+ / Co 2+ (E°=1.82 V) and Fe3+ / Fe 2+ (E°=0.77 V) Formation of redox pairs promotes electron transfer and significantly improves the decomposition efficiency of H2O2, thereby accelerating the degradation of microplastics; the layered structure anchors the metal active sites in the layers, and the interlayer anions CO32- through spontaneous intercalation of CO2 in the air... 2- The strong electrostatic interaction forms a stable sandwich structure, which protects the active sites of the metal and prevents the dissolution of metal ions, thus significantly improving the cycle stability of the catalyst. The bimetallic catalyst can reduce the amount of precious metals used and can be prepared at low cost through co-precipitation. The resulting colored micro-nanoplastics integrate coloring, catalysis, anti-aging and self-repair.

[0010] This invention also provides a method for preparing colored micro / nanoplastics products, comprising the following steps: S1, melt blending The polymer matrix and inorganic pigment are mixed evenly, and then melt-blended at 170~190℃ for 5~15min using a twin-screw extruder to obtain pigment-colored plastic solids. S2, Post-processing The pigment-colored plastic solid is processed in a pulverizer at a pulverization speed of 200-300 r / min for 10-15 min. Then, the pulverized pigment-colored plastic solid is washed with ethanol and water alternately until the filtrate is clear and transparent with a pH of 6-7. Finally, it is dried at a drying temperature of 80-120℃ for 2-4 h to obtain the colored micro-nano plastic product. Note: The above pulverization parameters ensure sufficient shearing and mixing while avoiding overheating and degradation of materials due to excessive rotation speed. The pulverization time ensures that the pigments achieve good dispersion in the polymer matrix. The above drying parameters effectively remove moisture and prevent bubbles or surface defects from occurring during subsequent processing.

[0011] Furthermore, the Fe-based bimetallic structure is subjected to surface modification treatment before melt blending; The surface modification treatment method is as follows: Step 1: Mix the dried Fe-based bimetallic structure with vinyl silane coupling agent at a mass ratio of 100:1~5 to obtain a mixture. Place the mixture in an ethanol solution at 60~80℃ for 2~4h according to the ratio of Fe-based bimetallic structure to ethanol solution of 1g:20-40 mL to obtain a vinyl-modified Fe-based bimetallic structure. Step 2: Under nitrogen protection, the vinyl-modified Fe-based bimetallic structure is dispersed in toluene at a ratio of 1g:30~50mL. The mixture is ultrasonically treated for 20~30min at a power of 195~300W. Styrene monomer, accounting for 10~50wt% of the vinyl-modified Fe-based bimetallic structure, is added and stirred until homogeneous. The temperature is raised to 70~75℃, and ammonium persulfate solution, accounting for 0.5~2wt% of the styrene monomer, is added dropwise at a dropping rate of 1~2 drops / s. The mixture is kept at 60~80℃ for 2~6h. After the reaction is completed, the mixture is filtered, washed, and dried to obtain the ammonium persulfate@Fe-based bimetallic structure composite. Note: Inorganic pigments and organic polymer matrices (PP, PS, PE) differ greatly in surface energy and polarity. Direct mixing can easily lead to agglomeration due to interfacial incompatibility. By using surface grafting polymerization to form a polymer coating layer on the surface of the Fe-based layered bimetallic structure, the agglomeration problem of inorganic nanomaterials in organic polymers is effectively solved, while maintaining the layered structure and catalytic activity of the Fe-based layered bimetallic structure.

[0012] Furthermore, the vinylsilane coupling agent is vinyltriethoxysilane or vinyltrimethoxysilane; Note: Both coupling agents can effectively improve the dispersibility of Fe-based layered bimetallic structures in polymer matrices, prevent aggregation, and maintain the layered structure and catalytic activity.

[0013] An application of a colored micro / nanoplastics product is disclosed, which is used in the catalytic degradation of TMB or organic pollutants and the catalytic self-degradation of colored micro / nanoplastics. The catalytic degradation method of the TMB or organic pollutants is as follows: the colored micro / nanoplastics product is placed in an oxidant solution at a ratio of 0.1~1.0g:50mL, and then the TMB or organic pollutants are added at a mass ratio of 1:10~100 to the oxidant. The reaction is carried out at room temperature and pressure for 0.5~24h. The method for catalytic self-degradation of the colored micro / nanoplastics is as follows: the colored micro / nanoplastics product is placed in an oxidant solution at a ratio of 0.1~1.0g:50 mL, and then reacted at 190~210℃ for 12~24 h. Explanation: When pulverized particles are placed under oxidant conditions, metallic pigments can catalyze the generation of a large amount of ROS, inducing polymer chain breakage and accelerating self-degradation. The metallic pigments act as an endogenous catalyst, enabling the plastic to degrade itself without the need for additional exogenous metallic catalysts. Under the above treatment conditions, the valence state of the metallic oxide pigments may change, leading to changes in color or spectrum, which can be used to indicate the plastic degradation process. The pigments both participate in catalysis and serve as an indicator signal of the degradation state, achieving "self-monitoring".

[0014] Furthermore, the oxidant solutions are all 0.15~0.25 mol / L H2O2 solutions.

[0015] Compared with existing technologies, the beneficial effects of this invention are: (1) This invention introduces metal oxide pigments with enzyme-like activity, which is different from traditional Fenton or nanocatalytic systems. The catalytic center comes from the pigment in the plastic, and no additional metal is needed. The plastic itself becomes the catalyst carrier. The resulting colored micro- and nano-plastic products can significantly catalyze the production of ROS from H2O2, exhibit peroxidase-like activity, and can also achieve the additional function of degrading coexisting pollutants (such as the organic pollutant antibiotic tetracycline). At the same time, the degradation process can be monitored by converting the valence state change of Fe in the inorganic pigment into a visual monitoring of the degradation process.

[0016] (2) This invention prepares a Fe-based layered bimetallic structure, which utilizes the strong electronic synergistic effect between the two metal ions in the Fe-based layered bimetallic structure to promote electron transfer, thereby improving the decomposition efficiency of H2O2 and further accelerating the degradation of microplastics; the layered structure can also anchor the metal active sites in the layers, and the interlayer anions CO3 spontaneously intercalate through CO2 in the air. 2- The strong electrostatic interaction forms a stable sandwich structure, which protects the active sites of the metal and prevents the dissolution of metal ions, further improving the cycle stability of the catalyst. At the same time, the bimetallic catalyst can reduce the amount of precious metals used and achieve low-cost preparation through co-precipitation method, resulting in colored micro-nanoplastics products that integrate coloring, catalysis, anti-aging and self-repair.

[0017] (3) Before melt blending, the Fe-based layered bimetallic structure is surface modified. By in-situ polymerization, a polystyrene layer is coated on the surface of the Fe-based layered bimetallic structure that has been grafted with vinyl groups. This significantly improves the dispersion stability of the Fe-based layered bimetallic structure and ensures uniform distribution when blended with the polymer matrix. This avoids the problem that inorganic pigments and organic polymer matrices have huge differences in surface energy and polarity, and that direct mixing is prone to agglomeration due to interfacial incompatibility. At the same time, the layered structure and catalytic activity of the Fe-based layered bimetallic structure are maintained. Attached Figure Description

[0018] Figure 1 This is a graph showing the trend of absorbance of oxTMB over time in the colored micro / nanoplastics system prepared by this invention. Figure 2 This is a graph showing the trend of hTPA fluorescence intensity versus time in the colored micro / nanoplastics system prepared by this invention. Figure 3This invention relates to the effect of colored micro / nanoplastics products prepared by this invention on the removal rate of tetracycline (TC) in an H2O2 system. Figure 4 This is a mass loss diagram of the catalytic self-degradation of the colored micro / nanoplastics products prepared by this invention; Figure 5 This is a carbonyl index diagram of the catalytic self-degradation of the colored micro / nanoplastics products prepared by this invention; Figure 6 This is a diagram of the total organic carbon content of the colored micro / nanoplastics product prepared by the present invention undergoing catalytic self-degradation. Figure 7 This is a diagram of the total inorganic carbon content of the colored micro / nanoplastics products prepared according to the present invention, which undergoes catalytic self-degradation. Figure 8 a-1 and a-2 are morphological images of 728-PSMPs with a pigment content of 4.8% obtained in this invention; b-1 and b-2 are morphological images of 728-PSMPs after 4 h of H2O2 hydrothermal oxidation reaction; c-1 and c-2 are morphological images of 728-PSMPs after 8 h of H2O2 hydrothermal oxidation reaction; d-1 and d-2 are morphological images of 728-PSMPs after 12 h of H2O2 hydrothermal oxidation reaction; e-1 and e-2 are morphological images of 728-PSMPs after 18 h of H2O2 hydrothermal oxidation reaction; f-1 and f-2 are morphological images of 728-PSMPs after 24 h of H2O2 hydrothermal oxidation reaction. Figure 9 This is a color change diagram of the colored micro / nanoplastics product obtained by the present invention as the reaction time increases; Figure 10 These are catalytic effects of the colored micro / nanoplastics products prepared in Examples 1 to 21 of this invention on organic pollutant TC. Figure 11 This is a diagram showing the catalytic effect of colored micro / nanoplastics products prepared in Examples 1 / 17, 4, and 22-27 of this invention on organic pollutant TC. Detailed Implementation

[0019] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.

[0020] Example 1: A colored micro / nanoplastics product is prepared by mixing a polymer matrix and an inorganic pigment in a mass ratio of 10:1; the polymer matrix is ​​polypropylene; the inorganic pigment is iron oxide pigment. The iron oxide pigments used are commercially available, specifically Bayer. Ⓡ 4610 Light Brown Iron Oxide Pigment; Bayer Ⓡ660 Dark Brown Iron Oxide Pigment; 728 Iron Oxide Black Fe3O4 Content >98.7%; Bayer Ⓡ 4686 Dark brown iron oxide pigment; An application of a colored micro / nanoplastics product is described, which is used in the catalytic degradation of organic pollutant TC. The catalytic degradation method is as follows: the colored micro / nanoplastics product is placed in an oxidant solution at a ratio of 0.5g:50mL, and then organic pollutant TC is added at a mass ratio of 1:55 to oxidant. The reaction is carried out at 25℃ and 0.1MPa for 18 h. It was applied to the catalytic self-degradation of colored micro- and nano-plastics. The method for catalytic self-degradation of colored micro- and nano-plastics was as follows: the colored micro- and nano-plastic products were placed in an oxidant solution at a ratio of 0.5g:50mL, and then reacted at 200℃ for 12h and 24h respectively; the oxidant solution was a 0.2mol / L H2O2 solution.

[0021] Example 2: Unlike Example 1, a colored micro / nanoplastics product is prepared by mixing a polymer matrix and an inorganic pigment in a mass ratio of 2:1; the polymer matrix is ​​polystyrene.

[0022] Example 3: Unlike Example 1, a colored micro / nanoplastics product is prepared by mixing a polymer matrix and an inorganic pigment in a mass ratio of 20:1; the polymer matrix is ​​polyethylene.

[0023] Example 4: Unlike Example 1, the inorganic pigment is an inorganic pigment containing an Fe-based layered bimetallic structure. The Fe-based layered bimetallic structure is composed of Fe... 3+ With Mg 2+ Prepared from; The preparation method of the inorganic pigment containing Fe-based layered bimetallic structure is as follows: the Fe-based layered bimetallic structure is placed in a tube furnace, heated to 300℃ and held for 30 min under air atmosphere and heating rate of 5℃ / min, then heated to 550℃ and calcined for 3 h at a heating rate of 4℃ / min, then heated to 1250℃ and calcined for 7 h at a heating rate of 5℃ / min, cooled to 25℃ with the furnace, and ball-milled to 80~100 mesh at 150 rpm to obtain the inorganic pigment containing Fe-based layered bimetallic structure. The preparation method of Fe-based basal bimetallic structures is as follows: A 0.15 mol / L MgCl2·6H2O solution and a 0.15 mol / L Fe(NO3)3 solution were mixed at a molar ratio of 3:1 and dissolved in 300 mL of deionized water to obtain a Fe-based metal salt mixed solution. The Fe-based metal salt mixed solution and a 0.3 mol / L NaOH solution were simultaneously added dropwise to the reaction vessel at a volume ratio of 1:1 at a dropping rate of 2 drops / s, with the pH controlled at 9.5. The mixture was stirred continuously at 70 °C for 4 h. The precipitate was then transferred to a high-pressure reactor and subjected to hydrothermal reaction at 130 °C for 18 h. Finally, the mixture was centrifuged at 4500 rpm for 8 min, and the precipitate was collected. The precipitate was washed four times alternately with deionized water and anhydrous ethanol until the pH of the filtrate reached 6.5, with each washing lasting 13 min. Finally, the filtrate was dried in a vacuum drying oven at 70 °C for 18 h to obtain a Fe-based layered bimetallic structure.

[0024] Example 5: Unlike Example 4, the Fe-based layered bimetallic structure is composed of Fe 3+ with Ni 2+ The preparation method of the inorganic pigment containing the Fe-based layered bimetallic structure is as follows: The Fe-based layered bimetallic structure is placed in a tube furnace, heated to 290℃ and held for 25 min under air atmosphere and a heating rate of 5℃ / min. Then, it is heated to 500℃ and calcined for 2 h at a heating rate of 3℃ / min, followed by calcination at 1100℃ for 2 h at a heating rate of 5℃ / min. After cooling to 22℃ in the furnace, it is ball-milled at 100 rpm to a fineness of 80-100 mesh, thus obtaining the inorganic pigment containing the Fe-based layered bimetallic structure; wherein, Ni... 2+ The corresponding salt solution is NiCl2·6H2O.

[0025] Example 6: Unlike Example 4, the Fe-based layered bimetallic structure is composed of Fe 3+ and Zn 2+ The preparation method of the inorganic pigment containing the Fe-based layered bimetallic structure is as follows: The Fe-based layered bimetallic structure is placed in a tube furnace, heated to 310℃ and held for 35 min under air atmosphere and a heating rate of 5℃ / min. Then, it is heated to 600℃ and calcined for 4 h at a heating rate of 5℃ / min, followed by calcination to 1400℃ and calcination for 10 h at a heating rate of 5℃ / min. The furnace is then cooled to 30℃, and the pigment is ball-milled to 80-100 mesh at 200 rpm to obtain the Fe-based layered bimetallic structure. Among them, Zn... 2+ The corresponding salt solution is ZnCl2·6H2O.

[0026] Example 7: Unlike Example 4, the Fe-based bimetallic layer is composed of Fe 3+ With Co 2+ Prepared from; wherein, Co2+ The corresponding salt solution is CoCl2·6H2O.

[0027] Example 8: Unlike Example 4, the Fe-based bimetallic layer is composed of Fe 3+ With Cu 2+ Prepared from; wherein, Cu 2+ The corresponding salt solution is CuCl2·2H2O.

[0028] Example 9: Unlike Example 4, a 0.1 mol / L MgCl2·6H2O solution and a 0.1 mol / L Fe(NO3)3 solution were mixed in a 2:1 molar ratio and dissolved in 100 mL of deionized water to obtain a Fe-based metal salt mixed solution.

[0029] Example 10: Unlike Example 4, a 0.2 mol / L MgCl2·6H2O solution and a 0.2 mol / L Fe(NO3)3 solution were mixed in a molar ratio of 4:1 and dissolved in 500 mL of deionized water to obtain a Fe-based metal salt mixed solution.

[0030] Example 11: Unlike Example 4, Fe-based metal salt mixed solution and 0.1 mol / L NaOH solution were simultaneously added dropwise to the reaction vessel at a volume ratio of 1:1, with a dropping rate of 2 drops / s. The pH was controlled at 9, and the mixture was stirred continuously at 60°C for 2 hours. The precipitate was then transferred to a high-pressure reactor and hydrothermally reacted at 100°C for 12 hours.

[0031] Example 12: Unlike Example 4, Fe-based metal salt mixed solution and 0.5 mol / L NaOH solution were simultaneously added dropwise to the reaction vessel at a volume ratio of 1:1, with a dropping rate of 3 drops / s. The pH was controlled at 10, and the mixture was stirred continuously at 80°C for 6 hours. The precipitate was then transferred to a high-pressure reactor and hydrothermally reacted at 150°C for 24 hours.

[0032] Example 13: Unlike Example 4, the precipitate was centrifuged at 3000 rpm for 5 min, and then washed three times with deionized water and anhydrous ethanol until the pH of the filtrate was 6, with each washing time being 10 min. Finally, the filtrate was dried in a vacuum drying oven at 60℃ for 12 h to obtain a Fe-based bimetallic structure.

[0033] Example 14: Unlike Example 4, the precipitate was centrifuged at 6000 rpm for 10 min, and then washed 5 times with deionized water and anhydrous ethanol until the pH of the filtrate was 7, with each washing time being 15 min. Finally, the filtrate was dried in a vacuum drying oven at 80℃ for 24 h to obtain a Fe-based bimetallic structure.

[0034] Example 15: Unlike Example 1, the catalytic degradation method of organic pollutant TC is as follows: colored micro-nano plastic products are placed in an oxidant solution at a ratio of 0.1g:50mL, and then organic pollutant TC is added at a mass ratio of 1:10 to oxidant. The reaction is carried out at 25℃ and 0.1MPa for 12h. The method for catalytic self-degradation of colored micro / nanoplastics is as follows: the colored micro / nanoplastics product is placed in an oxidant solution at a ratio of 0.1g:50mL, and then reacted at 190℃ for 12h and 24h respectively. The oxidant solutions were all 0.15 mol / L H2O2 solutions.

[0035] Example 16: Unlike Example 1, the catalytic degradation method of organic pollutant TC is as follows: colored micro-nano plastic products are placed in an oxidant solution at a ratio of 1.0g:50mL, and then organic pollutant TC is added at a mass ratio of 1:100 to oxidant. The reaction is carried out at 25℃ and 0.1MPa for 24 h. The method for catalytic self-degradation of colored micro / nanoplastics is as follows: the colored micro / nanoplastics product is placed in an oxidant solution at a ratio of 1.0g:50mL, and then reacted at 210℃ for 12h and 24h respectively. The oxidizing agent solution is a 0.25 mol / L H2O2 solution.

[0036] Example 17: Unlike Example 1, a method for preparing a colored micro / nanoplastics product includes the following steps: S1, melt blending The polymer matrix and inorganic pigments are mixed evenly, and then melt-blended at 180°C for 10 minutes using a twin-screw extruder to obtain pigment-colored plastic solids. S2, Post-processing The pigment-colored plastic solid was processed in a pulverizer at a pulverization speed of 250 r / min for 13 min. Then, the pulverized pigment-colored plastic solid was washed with ethanol and water alternately until the filtrate was clear and transparent with pH=6.5. Finally, it was dried at a drying temperature of 100℃ for 3 h to obtain colored micro-nano plastic products.

[0037] Example 18: Unlike Example 17, a pigment-colored plastic solid was obtained by melt blending at 170°C for 5 minutes using a twin-screw extruder.

[0038] Example 19: Unlike Example 17, a pigment-colored plastic solid was obtained by melt blending at 190°C for 15 minutes using a twin-screw extruder.

[0039] Example 20: Unlike Example 17, the pigment-colored plastic solid was processed in a pulverizer at a pulverization speed of 200 r / min for 10 min, and then washed with ethanol and water alternately until the filtrate was clear and transparent with pH=6. Finally, it was dried at a drying temperature of 80℃ for 2 h to obtain colored micro-nano plastic products.

[0040] Example 21: Unlike Example 17, the pigment-colored plastic solid was processed in a pulverizer at a pulverization speed of 300 r / min for 15 min, and then washed with ethanol and water alternately until the filtrate was clear and transparent with pH=7. Finally, it was dried at a drying temperature of 120℃ for 4 h to obtain colored micro-nano plastic products.

[0041] Example 22: Unlike Example 17, the Fe-based bimetallic structure underwent surface modification treatment before melt blending; The surface modification treatment method is as follows: Step 1: The dried Fe-based bimetallic structure was mixed with a vinyl silane coupling agent at a mass ratio of 100:3 to obtain a mixture. The mixture was then placed in an ethanol solution at 70°C and reacted for 3 hours at a ratio of 1 g of Fe-based bimetallic structure to 30 mL of ethanol solution to obtain a vinyl-modified Fe-based bimetallic structure. The vinyl silane coupling agent was vinyltriethoxysilane. Step 2: Under nitrogen protection, the vinyl-modified Fe-based bimetallic structure was dispersed in toluene at a ratio of 1g:40mL. The mixture was sonicated for 25min at a power of 225W. Styrene monomer (30wt% of the vinyl-modified Fe-based bimetallic structure) was added and stirred until homogeneous. The mixture was heated to 73℃ and ammonium persulfate solution (1.2wt% of the styrene monomer) was added dropwise at a dropping rate of 1 drop / s. The mixture was kept at 70℃ for 4h. After the reaction was completed, the mixture was filtered, washed, and naturally dried to obtain the ammonium persulfate@Fe-based bimetallic structure composite.

[0042] Example 23: Unlike Example 22, the dried Fe-based bimetallic structure was mixed with a vinyl silane coupling agent at a mass ratio of 100:1 to obtain a mixture. The mixture was then placed in an ethanol solution at 60°C and reacted for 2 hours according to a ratio of 1 g of Fe-based bimetallic structure to 20 mL of ethanol solution to obtain a vinyl-modified Fe-based bimetallic structure.

[0043] Example 24: Unlike Example 22, the dried Fe-based bimetallic structure was mixed with a vinyl silane coupling agent at a mass ratio of 100:5 to obtain a mixture. The mixture was then placed in an ethanol solution at 80°C and reacted for 4 hours at a ratio of 1 g of Fe-based bimetallic structure to 40 mL of ethanol solution to obtain a vinyl-modified Fe-based bimetallic structure.

[0044] Example 25: Unlike Example 22, the vinyl silane coupling agent is vinyltrimethoxysilane.

[0045] Example 26: Unlike Example 22, under nitrogen protection, a vinyl-modified Fe-based bimetallic structure was dispersed in toluene at a ratio of 1g:30mL. The mixture was ultrasonically treated for 20min at a power of 195W. Styrene monomer, accounting for 10wt% of the vinyl-modified Fe-based bimetallic structure, was added and stirred until homogeneous. The mixture was heated to 70℃, and ammonium persulfate solution, accounting for 0.5wt% of the styrene monomer, was added dropwise at a dropping rate of 1 drop / s. The mixture was kept at 60℃ for 2h. After the reaction was completed, the mixture was filtered, washed, and naturally dried to obtain the ammonium persulfate@Fe-based bimetallic structure composite.

[0046] Example 27: Unlike Example 22, under nitrogen protection, a vinyl-modified Fe-based bimetallic structure was dispersed in toluene at a ratio of 1g:50mL. The mixture was ultrasonically treated for 30min at a power of 300W. Styrene monomer accounting for 50wt% of the vinyl-modified Fe-based bimetallic structure was added, and the mixture was stirred and mixed evenly. The temperature was raised to 75℃, and ammonium persulfate solution accounting for 2wt% of the styrene monomer was added dropwise at a dropping rate of 2 drops / s. The mixture was kept at 80℃ for 6h. After the reaction was completed, the mixture was filtered, washed, and naturally dried to obtain the ammonium persulfate@Fe-based bimetallic structure composite.

[0047] Experimental Example: The description of this experimental example is based on the scheme described in Example 1 / 17, and aims to illustrate the practical application effect of the present invention.

[0048] In the attached figures, Control refers to the blank control group without colored micro / nanoplastics; 4610-PSMPs refers to polystyrene micro / nanoplastics colored with 4610 pigment; 4686-PSMPs refers to polystyrene micro / nanoplastics colored with 4686 pigment; 660-PSMPs refers to polystyrene micro / nanoplastics colored with 660 pigment; 728-PSMPs refers to polystyrene micro / nanoplastics colored with 728 pigment; 728-PSMPs (16.7%) refers to polystyrene micro / nanoplastics colored with 728 pigment with a pigment content of 16.7%; 728-PSMPs (28.6%) refers to polystyrene micro / nanoplastics colored with 728 pigment with a pigment content of 28.6%. 1. The performance of the colored micro / nanoplastics products prepared in Examples 1-3 and Examples 15-21 was tested. The results showed that the parameters within the scope of this application had relatively small impacts on the performance of the colored micro / nanoplastics products. Considering all factors, the colored micro / nanoplastics products with 728-PSMPs exhibited better performance under the technical solutions of Examples 1 / 17. Using the colored micro / nanoplastics products prepared in Examples 1 / 17 as the research object, the following studies were conducted: Depend on Figure 1 It can be seen that the absorbance of oxTMB in the iron-based pigment-colored microplastic sample system increases over time, indicating that the microplastic samples colored by different iron-based pigments all have certain peroxidase-like activities, and their activity order is: 4610-PSMPs < 4686-PSMPs < 660-PSMPs < 728-PSMPs.

[0049] Depend on Figure 2 It can be seen that the hTPA formation rate was significantly faster than that of the control group without 728-PSMPs, indicating that 728-PSMPs can effectively promote the decomposition of H2O2 to generate •OH. This is speculated to be related to the iron-based pigments in the 728-PSMPs. To further verify this hypothesis, 728-PSMPs with a higher 728 pigment content (28.6%) were tested. The results showed that as the 728 pigment content increased, the amount of •OH generated in the system also increased accordingly.

[0050] Depend on Figure 3 It can be seen that, under the H2O2 system, microplastics colored with four different iron-based pigments can accelerate the degradation of TC, indicating that they can catalyze the degradation and transformation of environmental pollutants.

[0051] Figures 4-7 The degradation performance of the iron-based pigment-colored microplastic samples obtained from the study was determined after reacting at 200℃ for 12 h and 24 h. Figure 4It can be seen that the colored microplastic samples containing 728 iron-based pigments had the highest mass loss rate, indicating that iron-based pigments played a promoting role in the self-degradation process of microplastic samples.

[0052] Depend on Figure 5 It can be seen that the carbonyl index analysis results show that pure polystyrene microplastics only exhibit slight oxidation characteristics after hydrothermal oxidation. The microplastic samples with added iron-based pigments show a higher amount of carbonyl functional groups generated during the degradation process, indicating that their oxidative degradation process is more complete.

[0053] Depend on Figure 6 It can be seen that the experimental group containing iron-based pigments produced a higher concentration of total organic carbon, confirming the promoting effect of iron-based pigments on the self-degradation of microplastics.

[0054] Depend on Figure 7 It can be seen that the experimental group containing iron-based pigments produced a higher concentration of total inorganic carbon, confirming the promoting effect of iron-based pigments on the self-degradation of microplastics.

[0055] SEM characterization is used to observe morphological changes on the surface of microplastics in order to analyze the impact of the degradation process on the microstructure of the material. Figure 8 The morphology of 728-PSMPs with an original pigment content of 4.8% and samples after hydrothermal oxidation with H2O2 at 4 h, 8 h, 12 h, 18 h, and 24 h is shown, including microplastic particles at different magnifications. Figure 8 As shown in a-1 and a-2, the original samples exhibit relatively intact microplastic particles with relatively smooth surfaces, clear edges, and no obvious signs of erosion. After 4 hours of degradation ( Figure 8 (b-1 and b-2) The particle surface showed obvious roughening and cracks, indicating that degradation had begun, but the overall structure remained largely intact. After 8 hours of reaction, the particle size decreased significantly, and pores formed on the surface. With further extension of the reaction time, the particles continued to degrade, exhibiting a highly porous and fractured state, with some fragments displaying a honeycomb structure. SEM images clearly showed the different stages of the iron-based pigment-colored microplastics in mediating their own degradation process. In the initial stage, the particle surface first underwent erosion and oxidation; as the reaction progressed, the active sites inside the particles were gradually exposed, pores formed around them, and they gradually transformed into honeycomb-structured fragments. After further degradation, the microplastics finally broke down completely, forming even smaller particles.

[0056] Depend on Figure 9It can be seen that as the reaction time increases, the color of the iron-based pigment-colored microplastic solid particles gradually changes from black to brown, indicating that the valence state of iron in the iron-based pigment has changed. It can be concluded that under the above treatment conditions, the valence state of metal oxide pigments changes, which in turn leads to changes in color or spectrum. This can be used to indicate the degradation process of plastics and serve as an indicator signal of the degradation state, thus achieving "self-monitoring".

[0057] 2. Investigating the effect of Fe-based layered bimetallic structures on the catalytic effect of colored micro / nanoplastics products. Conclusion: From Figure 10 The comparison of Examples 1 to 21 shows that the TC removal rate in Examples 1 / 17 reaches 88% after 8 hours, while the TC removal rate in Examples 4 to 14 reaches 93% after 8 hours. The main reason is that the strong electronic synergistic effect between the two metal ions in the Fe-layered bimetallic structure promotes electron transfer, thereby increasing the decomposition efficiency of H2O2 and further accelerating the degradation of microplastics. The layered structure also anchors the metal active sites within the layers, allowing for the spontaneous intercalation of CO2 from the air by interlayer anions (CO3). 2- The strong electrostatic interactions form a stable sandwich structure, which protects the active sites of the metal, prevents the dissolution of metal ions, further improves the cycle stability of the catalyst, and optimizes the catalytic effect.

[0058] 3. The effect of surface modification treatment of Fe-based bimetallic structures before melt blending on the catalytic effect of colored micro / nanoplastics products. Conclusion: From Figure 11 Comparing Examples 1 / 17, 4, and 22-27, it can be seen that the TC removal rate in Examples 4-14 reaches 93% after 8 hours, while the TC removal rate in Examples 22-27 reaches 95% after 8 hours. The main reason is that the inorganic pigments and organic polymer matrices have huge differences in surface energy and polarity. Direct mixing is prone to agglomeration due to interfacial incompatibility. By forming a polymer coating layer on the surface of the Fe-based bimetallic structure through surface grafting polymerization, the agglomeration problem of inorganic nanomaterials in organic polymers is effectively solved. At the same time, the layered structure and catalytic activity of the Fe-based bimetallic structure are maintained, thereby improving its catalytic effect. The parameter changes in Examples 22-27 have a relatively small catalytic effect on colored micro-nanoplastics. In summary, Example 22 is selected as the optimal solution.

Claims

1. A colored micro / nanoplastics product, characterized in that, It is prepared by mixing a polymer matrix and an inorganic pigment in a mass ratio of 2 to 20:1; the polymer matrix is ​​polypropylene, polystyrene, or polyethylene.

2. The colored micro / nanoplastics product as described in claim 1, characterized in that, The inorganic pigment is an iron oxide pigment.

3. The colored micro / nanoplastics product as described in claim 1, characterized in that, The inorganic pigment is an inorganic pigment containing an Fe-based basal bimetallic structure; the Fe-based basal bimetallic structure is composed of Fe... 3+ With Mg 2+ Ni 2+ Zn 2+ Co 2+ Cu 2+ It is prepared from any of the following methods; The preparation method of the Fe-based bimetallic structure inorganic pigment is as follows: the Fe-based bimetallic structure is placed in a tube furnace, heated to 290~310℃ under air atmosphere and heating rate of 5℃ / min and held for 25~35min, then heated to 500~600℃ at heating rate of 3~5℃ / min and calcined for 2~4h, then heated to 1100~1400℃ at heating rate of 5℃ / min and calcined for 2~10h, cooled to 22~30℃ in the furnace, and ball-milled to 80~100 mesh at 100~200rpm to obtain the Fe-based bimetallic structure inorganic pigment.

4. A colored micro / nanoplastics product as described in claim 3, characterized in that, The preparation method of the Fe-based bimetallic structure is as follows: A 0.1–0.2 mol / L divalent metal salt solution and a 0.1–0.2 mol / L Fe(NO3)3 solution were mixed at a molar ratio of 2–4:1 and dissolved in 100–500 mL of deionized water to obtain a Fe-based metal salt mixed solution. This Fe-based metal salt mixed solution was then simultaneously added dropwise to a reaction vessel at a volume ratio of 1:1 to a 0.1–0.5 mol / L NaOH solution at a dropping rate of 2–3 drops / s, with the pH controlled at 9–10. The mixture was stirred continuously at 60–80 °C for 2–6 h. The precipitate was then transferred to a high-pressure reactor and hydrothermally reacted at 100–150 °C for 12–24 h. Finally, the mixture was subjected to a high-pressure reactor at 3000–6000 °C. Centrifuge at rpm for 5-10 min, collect the precipitate, wash with deionized water and anhydrous ethanol alternately 3-5 times until the pH of the filtrate is 6-7, each washing time is 10-15 min, and finally dry in a vacuum drying oven at 60-80℃ for 12-24 h to obtain Fe base layer bimetallic structure.

5. A method for preparing a colored micro / nanoplastics product as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1, melt blending The polymer matrix and inorganic pigment are mixed evenly, and then melt-blended at 170~190℃ for 5~15min using a twin-screw extruder to obtain pigment-colored plastic solids. S2, Post-processing The pigment-colored plastic solid is processed by a pulverizer at a pulverization speed of 200-300 r / min for 10-15 min. Then, the pulverized pigment-colored plastic solid is washed with ethanol and water alternately until the filtrate is clear and transparent with a pH of 6-7. Finally, it is dried at a drying temperature of 80-120℃ for 2-4 h to obtain the colored micro-nano plastic product.

6. The method for preparing a colored micro / nanoplastics product as described in claim 5, characterized in that, Before melt blending, the Fe-based basal bimetallic structure is subjected to surface modification treatment; The surface modification treatment method is as follows: Step 1: Mix the dried Fe-based bimetallic structure with vinyl silane coupling agent at a mass ratio of 100:1~5 to obtain a mixture. Place the mixture in an ethanol solution at 60~80℃ for 2~4h according to the ratio of Fe-based bimetallic structure to ethanol solution of 1g:20-40 mL to obtain a vinyl-modified Fe-based bimetallic structure. Step 2: Under nitrogen protection, the vinyl-modified Fe-based bimetallic structure is dispersed in toluene at a ratio of 1g:30~50mL. The mixture is ultrasonically treated for 20~30min at a power of 195~300W. Styrene monomer, accounting for 10~50wt% of the vinyl-modified Fe-based bimetallic structure, is added and stirred until homogeneous. The temperature is raised to 70~75℃, and ammonium persulfate solution, accounting for 0.5~2wt% of the styrene monomer, is added dropwise at a dropping rate of 1~2 drops / s. The mixture is kept at 60~80℃ for 2~6h. After the reaction is completed, the mixture is filtered, washed, and naturally dried to obtain the ammonium persulfate@Fe-based bimetallic structure composite.

7. The method for preparing a colored micro / nanoplastics product as described in claim 6, characterized in that, The vinyl silane coupling agent is vinyltriethoxysilane or vinyltrimethoxysilane.

8. The application of a colored micro / nanoplastics product obtained by any one of the preparation methods of claims 5 to 7, characterized in that, It is applied to the catalytic degradation of TMB or organic pollutants and the catalytic self-degradation of colored micro / nanoplastics. The catalytic degradation method of TMB or organic pollutants is as follows: the colored micro / nanoplastics product is placed in an oxidant solution at a ratio of 0.1~1.0g:50mL, and then the TMB or organic pollutant is added at a mass ratio of 1:10~100 to oxidant. The reaction is carried out at room temperature and pressure for 0.5~24h. The method for catalytic self-degradation of the colored micro / nanoplastics is as follows: the colored micro / nanoplastics product is placed in an oxidant solution at a ratio of 0.1~1.0g:50 mL, and then reacted at 190~210℃ for 12~24 h.

9. The application of a colored micro / nanoplastics product as described in claim 8, characterized in that, The oxidant solutions are all 0.15~0.25 mol / L H2O2 solutions.

Images