Preparation method for recoverable removal of microplastics in water

Abstract

The invention provides a preparation method capable of recycling and removing micro-plastics in water, and particularly relates to a micro-plastic / manganese dioxide core-shell composite material synthesized by a hydrothermal method, the synthesized composite material is in a core-shell form with micro-plastics as a core and manganese dioxide as a shell, and the composite material is complete in morphology, uniform in size and good in mechanical property. Manganese dioxide grows on the surface of the micro-plastic in the form of nanosheets to form a petal-like, scale-like or nanorod-like structure covering or growing on the micro-plastic. The novel composite material not only can realize recycling of the micro-plastic and reduce the harm of the micro-plastic to the environment, but also can give full play to the excellent performance of the manganese dioxide. Meanwhile, the morphology and the structure of the material can be controlled to a certain extent by adopting a hydrothermal method, so that the material has better performance and application potential. The novel composite material is expected to provide a new way and method for solving the problem of micro-plastic pollution and expanding the material application field. The method is mainly suitable for the field of environmental governance.

Description

Technical Field

[0001] The patent of this invention belongs to the field of environmental governance, specifically a preparation method for removing microplastics in water with recyclability. Background Art

[0002] Microplastics (MPs) generally refer to plastic particles with a size of ≤5mm in the environment. These particles are not biodegradable. Under the action of photochemistry, they will produce smaller toxic fragments that enter the food chain and finally enter the human body. At the same time, microplastics will absorb organic matter and heavy metals in natural water bodies, posing a serious threat to human health.

[0003] Manganese dioxide is a material with multiple properties and application potential. It has good catalytic performance, electrochemical activity and adsorption capacity. In the environmental field, it can be used for catalytic degradation of pollutants, adsorption of heavy metal ions, etc. In the energy field, it can be used in battery electrode materials, supercapacitors, etc.

[0004] It is an innovative idea to combine microplastics with manganese dioxide to prepare a core-shell structure composite material. This new composite material can not only achieve the recycling and reuse of microplastics and reduce their harm to the environment, but also give full play to the excellent properties of manganese dioxide. The composite material is prepared by hydrothermal method, which can control the morphology and structure of the material to a certain extent, making it have better performance and application potential. The invention of this new composite material is expected to provide new ways and methods to solve the problem of microplastic pollution and expand the application field of materials, which has important scientific significance and practical application value. Summary of the invention

[0005] The present invention proposes a new idea and method for recycling microplastics in water. The present invention uses a hydrothermal method to directly prepare a microplastic / manganese dioxide core-shell composite material and attaches manganese dioxide to the surface of the microplastic.

[0006] Specifically, to achieve the above purpose, the technical solution of the present invention is as follows: In a first aspect of the present invention, a preparation method for removing microplastics from water with recyclability is provided.

[0007] In the present invention, a microplastic / manganese dioxide core-shell composite material is synthesized by a hydrothermal method, and the synthesized composite material presents a core-shell morphology with microplastics as the core and manganese dioxide as the shell, and its morphology is complete and uniform in size. Manganese dioxide grows on the surface of microplastics in the form of nanosheets, forming a structure similar to "petal-like", "scale-like" or "nano-rod-like" covering or growing on microplastics. This novel composite material can not only realize the recycling and reuse of microplastics, reduce its harm to the environment, but also give full play to the excellent performance of manganese dioxide. At the same time, the hydrothermal method is used to prepare the morphology and structure of the material to a certain extent, so that it has better performance and application potential. This novel composite material is expected to provide new ways and methods for solving the problem of microplastic pollution and expanding the application field of materials.

[0008] In the second aspect of the present invention, a method for preparing a microplastic / manganese dioxide core-shell composite material is provided: the pretreated microplastic is mixed with an aqueous solution of potassium permanganate and manganese sulfate, and the microplastic / manganese dioxide core-shell composite material is synthesized by a hydrothermal method.

[0009] According to an embodiment of the present invention, the microplastic particles include but are not limited to polypropylene (PP) and polyethylene (PE).

[0010] According to an embodiment of the present invention, the particle size range of the microplastics is 0.4 μm-4 mm.

[0011] According to an embodiment of the present invention, the microplastic pretreatment drying temperature is 50-80°C.

[0012] According to an embodiment of the present invention, the microplastic pretreatment drying time is 6-12 hours.

[0013] According to an embodiment of the present invention, the reagents for preparing manganese dioxide are potassium permanganate and manganese sulfate, but are not limited to potassium permanganate and manganese sulfate.

[0014] According to an embodiment of the present invention, the concentrations of potassium permanganate and manganese sulfate are 0.1-1 mol / L.

[0015] According to an embodiment of the present invention, the ratio of potassium permanganate, manganese sulfate and microplastics is 2:3:4, but not limited to 2:3:4.

[0016] According to an embodiment of the present invention, the solution is stirred for 15-30 minutes.

[0017] According to an embodiment of the present invention, the hydrothermal reaction temperature is 120-200°C.

[0018] According to an embodiment of the present invention, the hydrothermal reaction time is 6-24 hours.

[0019] According to an embodiment of the present invention, the separation method includes but is not limited to suction filtration and centrifugation.

[0020] According to an embodiment of the present invention, the washing times is 1-3 times.

[0021] According to an embodiment of the present invention, the drying temperature of the mixed solution is 50-80°C.

[0022] According to an embodiment of the present invention, the drying time of the mixed solution is 6-12 hours.

[0023] Compared with the existing methods, the invention has the following beneficial effects: the invention uses a hydrothermal method to compound microplastics with manganese dioxide to form a composite material with a core-shell structure. The new composite material can not only realize the recycling and reuse of microplastics and reduce their harm to the environment, but also give full play to the excellent properties of manganese dioxide. At the same time, the hydrothermal method can control the morphology and structure of the material to a certain extent, so that it has better performance and application potential. The new composite material is expected to provide a new way and method to solve the problem of microplastic pollution and expand the application field of materials. DETAILED DESCRIPTION

[0024] The following implementation method describes the embodiments of the present invention in detail, which are exemplary and non-restrictive.

[0025] In the embodiment of the present invention, the present invention provides a preparation method for removing microplastics from water with recyclability, wherein the reagents for preparing the microplastic / manganese dioxide core-shell composite material are potassium permanganate, manganese sulfate, and microplastic particles.

[0026] In the specific embodiment of the present invention, the potassium permanganate is but not limited to potassium permanganate.

[0027] In the specific embodiment of the present invention, the manganese sulfate is but not limited to manganese sulfate.

[0028] In a specific embodiment of the present invention, the microplastic particles include but are not limited to polypropylene (PP) and polyethylene (PE).

[0029] The particle size range of the microplastics is 0.4 μm-4 mm.

[0030] The ratio of potassium permanganate, manganese sulfate and microplastics includes but is not limited to 2:3:4.

[0031] The separation method includes but is not limited to filtration.

[0032] In a specific embodiment of the present invention, the microplastic particles are cleaned to remove impurities and pollutants on the surface, rinsed with deionized water for multiple times, and then dried in a vacuum drying oven at 50-80° C. for 6-12 hours to remove moisture and other volatile substances.

[0033] In a specific embodiment of the present invention, potassium permanganate and manganese sulfate with a concentration of 0.1-1 mol / L are weighed, dissolved in deionized water with the pretreated microplastics in a ratio of 2:3:4, and stirred or ultrasonically treated for 15-30 minutes to form a uniform mixed solution.

[0034] In a specific embodiment of the present invention, the mixed solution is transferred to a reaction kettle, and subjected to hydrothermal reaction at an oven temperature of 120-200° C. for 6-24 hours, and then cooled to room temperature.

[0035] In a specific embodiment of the present invention, the obtained sample is filtered and washed with deionized water and anhydrous ethanol for 1-3 times, the solid is separated and dried at a temperature of 60-80° C. for 12-24 hours to obtain the solid.

[0036] In a specific embodiment of the present invention, the performance of the composite material is analyzed after hydrothermal synthesis. Specifically, the analysis can be as follows: (1) The surface micromorphology of the microplastic / manganese dioxide core-shell composite material is observed by scanning electron microscopy (SEM, Hitachi S-4800 II); (2) The distribution of manganese dioxide around the microplastic is observed by transmission electron microscopy (TEM), and whether they form a core-shell structure mixed with each other; (3) The chemical elements and their contents of the composite material are analyzed by energy dispersive spectrometer (EDS, PV8200, Hitachi); (4) The phase structure of the composite material is characterized and analyzed by X-ray diffractometer (D / max-2500PC, Rigaku). (5) Raman spectroscopy (Horiba LabRAM HR Evolution) is used to determine the chemical structure and component distribution of the composite material. (6) Fourier transform infrared spectroscopy (FTIR, Great 20) is used to determine the chemical composition and chemical bond state of the composite material. Example

[0037] The method for preparing the microplastic / manganese dioxide core-shell composite material provided by the present invention comprises the following steps: (1) Rinse the microplastic particles with deionized water several times and then dry them in a vacuum drying oven at 50-80°C for 6-12 hours to remove moisture and other volatile substances; (2) Weigh a certain amount of potassium permanganate and manganese sulfate, dissolve them and pretreated microplastics in deionized water in a ratio of 2:3:4, and stir or ultrasonically treat for 15-30 minutes to form a uniform mixed solution; (3) The mixed solution is transferred to a reactor and subjected to a hydrothermal reaction at an oven temperature of 120-200°C for 6-24 hours. After the reaction is completed, the mixture is taken out and cooled to room temperature; (4) After filtering the obtained sample, washing it with deionized water and anhydrous ethanol for 1-3 times respectively, and drying it at a temperature of 50-80° C. for 6-12 hours, a microplastic / manganese dioxide core-shell composite material is obtained; (5) The sample obtained in step (4) is applied to environmental management fields such as anti-corrosion materials, catalyst carriers, wastewater treatment and air purification.

[0038] In this specification, the reference term "embodiment" is described as a specific feature, method, material or structure described in the sample. The present invention relates to the "specific technical field", and in particular to an innovative technical solution of the "embodiment". The embodiments of the invention are intended to solve these problems and provide more efficient, reliable or economical solutions. This embodiment provides a specific implementation method to demonstrate the practical effect and application value of the present invention. Through the detailed implementation steps and material and equipment description, the specific implementation process of the present invention is clearly understood.

Claims

1. A preparation method for removing microplastics from water with recyclability.

2. The method for preparing a microplastic / manganese dioxide core-shell composite material according to claim 1, characterized in that: The particle size of microplastics ranges from 0.4μm to 4mm.

3. The method for preparing a microplastic / manganese dioxide core-shell composite material according to claim 1, characterized in that: The pretreated microplastics were mixed with potassium permanganate and manganese sulfate aqueous solutions, and microplastic / manganese dioxide core-shell composites were directly synthesized by a hydrothermal method.

4. The method for preparing the microplastic / manganese dioxide core-shell composite material according to claim 3, characterized in that: The microplastic particles are cleaned to remove surface impurities and contaminants, rinsed with deionized water multiple times, and then dried in a vacuum drying oven at 50-80°C for 6-12 hours to remove moisture and other volatile substances. The specific drying temperature and time are determined according to the properties of the microplastics and experimental requirements.

5. The method for preparing the microplastic / manganese dioxide core-shell composite material according to claim 3, characterized in that: Weigh a certain amount of potassium permanganate and manganese sulfate, dissolve them and the pretreated microplastics in deionized water in a ratio of 2:3:4, and stir or ultrasonically treat for 15-30 minutes to form a uniform mixed solution.

6. The method for preparing the microplastic / manganese dioxide core-shell composite material according to claim 5, characterized in that: The mixed solution is transferred to a reaction kettle and subjected to hydrothermal reaction at an oven temperature of 120-200° C. for 6-24 hours. After the reaction is completed, the solid is separated to obtain the product.

7. The method for preparing the microplastic / manganese dioxide core-shell composite material according to claim 6, characterized in that: The method for separating the solid product includes suction filtration and centrifugation, and preferably, also includes the steps of washing and drying the separated solid product.

8. The method for preparing the microplastic / manganese dioxide core-shell composite material according to claim 7, characterized in that: After washing with deionized water and anhydrous ethanol for 1-3 times respectively, drying at a temperature of 50-80° C. for 6-12 hours, the obtained product is obtained.

9. A microplastic / manganese dioxide core-shell composite material obtained according to the preparation method according to any one of claims 2 to 8.

10. Application of the microplastic / manganese dioxide core-shell composite material according to claim 9 in environmental management fields such as anti-corrosion materials, catalyst carriers, wastewater treatment and air purification.