Preparation method of iron oxide / manganese dioxide / biochar composite material by using wastes such as micro-plastics

Abstract

The invention provides a preparation method of an iron oxide / manganese dioxide / biochar composite material by utilizing wastes such as micro-plastics, and particularly relates to a micro-plastic / iron oxide / manganese dioxide / biochar composite material synthesized by a hydrothermal method. The synthesized composite material takes micro-plastic as a core, the surface of the micro-plastic is uniformly coated with a shell layer formed by iron oxide and manganese dioxide, and the biochar is distributed on the surface of the iron oxide and manganese dioxide shell layer or a thin biochar covering layer is formed outside the shell layer. The preparation method is expected to solve the problem of micro-plastic pollution, integrates the advantages of all the materials to obtain a novel material with excellent performance, realizes recycling of wastes such as micro-plastic and preparation of a high-performance composite material, and is further applied to the fields of environmental governance such as separation, adsorption and degradation, catalysis, energy storage and conversion and the like. 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 method for preparing an iron oxide / manganese dioxide / biochar composite material using waste such as microplastics. Background Art

[0002] Currently, microplastic pollution has become a global environmental problem. Microplastics are widely present in water bodies, soil and other environments, and their sources include the decomposition of plastic products and industrial production waste. Microplastics are not only difficult to degrade naturally, but also cause serious harm to the ecosystem. For example, if they are accidentally eaten by organisms, they will affect their growth and reproduction. At the same time, they may carry harmful substances into the food chain, threatening human health.

[0003] Iron oxide has magnetism and certain catalytic properties, and has potential for application in magnetic separation and pollutant degradation. Manganese dioxide is a good catalyst and electrode material, which can be used in catalytic oxidation reactions and batteries. Biochar is produced by pyrolysis of biomass, has a rich pore structure and good adsorption properties, can improve soil quality and adsorb pollutants, and can realize the resource utilization of waste biomass.

[0004] However, existing microplastic treatment methods have limited effects, and there are many problems in the preparation of composite materials. For example, traditional treatment methods may cause secondary pollution, the preparation process of composite materials is complicated and costly, the performance is difficult to meet actual needs, and the interface compatibility of microplastics when compounded with other materials needs to be solved urgently.

[0005] The hydrothermal method has unique advantages in material preparation. Its mild reaction conditions can reduce energy consumption and safety risks; the product has good crystallinity and high purity, which is conducive to improving performance; the morphology and size can be precisely controlled; and it is environmentally friendly and energy-saving, in line with the concept of sustainable development. The use of the hydrothermal method to prepare composite materials of microplastics, iron oxide, manganese dioxide and biochar is expected to combine the advantages of each material to achieve efficient removal of environmental pollutants and resource recycling. Summary of the invention

[0006] The present invention proposes a new idea and method for recycling and reusing waste such as microplastics. The present invention uses a hydrothermal method to prepare a microplastic / iron oxide / manganese dioxide / biochar composite material, which has microplastics as the core and a shell formed by iron oxide and manganese dioxide evenly wrapped on its surface. The biochar is distributed on the surface of the iron oxide and manganese dioxide shell or forms a thin biochar covering layer outside the shell.

[0007] 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 method for preparing an iron oxide / manganese dioxide / biochar composite material using waste materials such as microplastics is provided.

[0008] The present invention adopts a hydrothermal method to synthesize a microplastic / iron oxide / manganese dioxide / biochar composite material. The synthesized composite material has microplastics as the core, and its surface is evenly coated with a shell formed by iron oxide and manganese dioxide, and the biochar is distributed on the surface of the iron oxide and manganese dioxide shell or forms a thin biochar covering layer outside the shell. While this preparation method is expected to solve the problem of microplastic pollution, it also combines the advantages of various materials to obtain a new material with excellent performance, realizes the recycling of waste such as microplastics and the preparation of high-performance composite materials, and is further applied to separation, adsorption, degradation and other environmental governance, catalysis, energy storage and conversion and other fields.

[0009] In the second aspect of the present invention, a microplastic / iron oxide / manganese dioxide / biochar composite material is provided: the pretreated microplastic is first fully mixed with an iron salt solution, and then the prepared manganese dioxide precursor solution and biochar powder are added to the above mixed solution, and after sufficient mixing, the microplastic / iron oxide / manganese dioxide / biochar composite material is synthesized by a hydrothermal method.

[0010] According to an embodiment of the present invention, the microplastic particles include but are not limited to polypropylene (PP) and polyethylene (PE).

[0011] According to an embodiment of the present invention, the particle size range of the microplastics is 0.4 μm-4 mm.

[0012] According to an embodiment of the present invention, the microplastic pretreatment drying temperature is 50-80°C.

[0013] According to an embodiment of the present invention, the microplastic pretreatment drying time is 6-12 hours.

[0014] According to an embodiment of the present invention, the reagent for preparing the iron salt solution is ferric chloride, but is not limited to ferric chloride.

[0015] According to an embodiment of the present invention, the concentration of the iron salt solution is 0.1-1 mol / L.

[0016] 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.

[0017] According to an embodiment of the present invention, the concentration of the manganese dioxide precursor solution is 0.1-1 mol / L.

[0018] According to an embodiment of the present invention, the waste for preparing biochar includes but is not limited to straw, fruit shells, wood chips, branches and fallen leaves.

[0019] According to an embodiment of the present invention, the ratio of the manganese dioxide precursor solution, the iron salt solution, the biochar and the microplastics is 2:3:4:5, but not limited to 2:3:4:5.

[0020] According to an embodiment of the present invention, the magnetic stirring time is 1-3 hours.

[0021] According to an embodiment of the present invention, the hydrothermal reaction temperature is 120-200°C.

[0022] According to an embodiment of the present invention, the hydrothermal reaction time is 6-24 hours.

[0023] According to an embodiment of the present invention, the separation method includes but is not limited to suction filtration and centrifugation.

[0024] According to an embodiment of the present invention, the washing times is 1-3 times.

[0025] According to an embodiment of the present invention, the drying temperature of the mixed solution is 60-80°C.

[0026] According to an embodiment of the present invention, the drying time of the mixed solution is 6-12 hours.

[0027] The beneficial effects of the patent of the present invention compared with the existing methods are as follows: the present invention adopts a hydrothermal method to synthesize microplastic / iron oxide / manganese dioxide / biochar composite materials, thereby achieving efficient removal of environmental pollutants and resource recycling. The synthesized new composite materials combine the advantages of various materials and can be further applied to separation, adsorption, degradation and other environmental governance, catalysis, energy storage and conversion and other fields. DETAILED DESCRIPTION

[0028] The following implementation method describes the embodiments of the present invention in detail, which are exemplary and non-restrictive.

[0029] In the embodiment of the present invention, the present invention provides a method for preparing an iron oxide / manganese dioxide / biochar composite material using waste such as microplastics. The reagents for preparing the iron oxide / manganese dioxide / biochar composite material are potassium permanganate, manganese sulfate, ferric chloride, fruit shells, and microplastic particles.

[0030] The potassium permanganate mentioned herein is but not limited to potassium permanganate.

[0031] The manganese sulfate is but not limited to manganese sulfate.

[0032] The ferric chloride described is but not limited to ferric chloride.

[0033] The fruit shell described is not limited to the fruit shell.

[0034] The microplastic particles include but are not limited to polypropylene (PP) and polyethylene (PE).

[0035] The particle size range of the microplastics is 0.4 μm-4 mm.

[0036] The ratio of the potassium permanganate solution, the iron salt solution, the biochar and the microplastics is 2:3:4:5, but not limited to 2:3:4:5.

[0037] The separation method includes but is not limited to filtration.

[0038] 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.

[0039] In a specific embodiment of the present invention, a certain amount of ferric chloride is weighed and dissolved in an appropriate amount of deionized water to prepare an iron salt solution with a concentration of 0.1-1 mol / L.

[0040] In a specific embodiment of the present invention, a certain amount of potassium permanganate and manganese sulfate are weighed as precursors and dissolved in deionized water to prepare a manganese dioxide precursor solution with a concentration of 0.1-1 mol / L.

[0041] In a specific embodiment of the present invention, the fruit shell is dried and crushed, and then pyrolyzed under anoxic conditions to obtain biochar.

[0042] In a specific embodiment of the present invention, the biochar is ground into powder, and then cleaned and dried to remove impurities.

[0043] In a specific embodiment of the present invention, the pretreated microplastics are added to an iron salt solution and stirred with a magnetic stirrer for 1-3 hours to ensure that the microplastics are in full contact with the iron salt.

[0044] In a specific embodiment of the present invention, the prepared manganese dioxide precursor solution and biochar powder are added to the mixed solution containing microplastics and iron salt solution, and magnetic stirring is performed for 1-3 hours to fully mix the three.

[0045] In a specific embodiment of the present invention, the mixed solution is transferred to a reaction kettle and subjected to a hydrothermal reaction at an oven temperature of 120-200° C. for 6-24 hours. After completion, the mixed solution is filtered and washed with deionized water and anhydrous ethanol for 1-3 times to separate the solid, which is then dried at a temperature of 60-80° C. for 6-12 hours to obtain the obtained product.

[0046] 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 / iron oxide / manganese dioxide / biochar composite material is observed by scanning electron microscopy (SEM, Hitachi S-4800Ⅱ); (2) The distribution of biochar, iron oxide and 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 LabRAMHR 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

[0047] The method for preparing the microplastic / iron oxide / manganese dioxide / biochar composite material provided by the present invention comprises the following steps: (1) Wash the microplastic particles to remove impurities and contaminants on the surface. Rinse with deionized water several times, and then dry 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 ferric chloride and dissolve it in an appropriate amount of deionized water to prepare an iron salt solution with a concentration of 0.1-1 mol / L; (3) Weighing a certain amount of potassium permanganate and manganese sulfate as precursors and dissolving them in deionized water to prepare a manganese dioxide precursor solution with a concentration of 0.1-1 mol / L; (4) Drying and crushing the fruit shells, and then pyrolyzing them under anaerobic conditions to obtain biochar. The biochar is then ground into powder, washed, dried, and impurities removed; (5) Add the pretreated microplastics to the iron salt solution and stir with a magnetic stirrer for 1-3 hours to ensure that the microplastics are in full contact with the iron salt; (6) adding the prepared manganese dioxide precursor solution and biochar powder to the mixed solution containing microplastics and iron salt solution, and magnetically stirring for 1-3 hours to fully mix the three; (7) The mixed solution is transferred to a reactor and placed in an oven at 120-200°C for 6-24 hours for hydrothermal reaction. After the reaction is completed, the mixture is taken out and cooled to room temperature; (8) washing with deionized water and anhydrous ethanol for 1-3 times respectively, and drying at a temperature of 60-80° C. for 6-12 hours to obtain a microplastic / iron oxide / manganese dioxide / biochar composite material; (9) Apply the sample obtained in step (8) to separation, adsorption, degradation and other environmental management, catalysis, energy storage and conversion and other fields.

[0048] 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 method for preparing an iron oxide / manganese dioxide / biochar composite material using waste such as microplastics.

2. The method for preparing an iron oxide / manganese dioxide / biochar composite material using waste such as microplastics according to claim 1, characterized in that: The pretreated microplastic particles with a particle size range of 0.4 μm-4 mm were mixed with potassium permanganate, iron salt solution and biochar, and the microplastic / iron oxide / manganese dioxide / biochar composites were synthesized by a hydrothermal method.

3. The method for preparing the microplastic / iron oxide / manganese dioxide / biochar composite material according to claim 2, characterized in that: The microplastic particles are rinsed multiple times with deionized water to remove impurities and pollutants on the surface, 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.

4. The method for preparing the microplastic / iron oxide / manganese dioxide / biochar composite material according to claim 2, characterized in that: A certain amount of iron salt is weighed and dissolved in an appropriate amount of deionized water to prepare an iron salt solution of a certain concentration. Potassium permanganate and manganese sulfate are used as precursors of manganese dioxide. According to a certain stoichiometric ratio, the precursors are dissolved in deionized water to prepare a manganese dioxide precursor solution.

5. The method for preparing the microplastic / iron oxide / manganese dioxide / biochar composite material according to claim 2, characterized in that: The straw, fruit shells, wood chips, branches or other organic wastes are dried and crushed, and then pyrolyzed under oxygen-deficient or oxygen-limited conditions to obtain biochar, which is then ground into powder and cleaned and dried to remove impurities.

6. The method for preparing the microplastic / iron oxide / manganese dioxide / biochar composite material according to claim 2, characterized in that: The pretreated microplastics are added to the iron salt solution and stirred with a magnetic stirrer for 1-3 hours to ensure that the microplastics are in full contact with the iron salt. The prepared manganese dioxide precursor solution and biochar powder are then added to the mixed solution containing microplastics and iron oxide precursors, and magnetically stirred for 1-3 hours to fully mix the three.

7. The method for preparing the microplastic / iron oxide / manganese dioxide / biochar composite material according to claim 6, characterized in that: The mixed solution is transferred to a reaction kettle, placed in an oven at 120-200°C and heated for 6-24 hours for hydrothermal reaction. After the reaction is completed, it is washed with deionized water and anhydrous ethanol for 1-3 times respectively, and dried at 60-80°C for 6-12 hours to separate the solid.

8. A microplastic / iron oxide / manganese dioxide / biochar composite material obtained according to the preparation method according to any one of claims 2 to 8.

9. Application of the microplastic / iron oxide / manganese dioxide / biochar composite material according to claim 8 in the fields of separation, adsorption, degradation, environmental management, catalysis, energy storage and conversion.