Method for preparing bamboo-based magnetic activated carbon and analyzing adsorption capacity of bamboo-based magnetic activated carbon to micro-plastics

Abstract

The invention discloses a method for preparing bamboo-based magnetic activated carbon and analyzing the adsorption capacity of the bamboo-based magnetic activated carbon to micro-plastics, and relates to the technical field of bamboo-based magnetic activated carbon. The method comprises the following steps: 1, preparing a high-performance bamboo-based magnetic activated carbon adsorption material; 2, analyzing the characteristics of the bamboo-based magnetic activated carbon and the micro-plastic; 3, analyzing multi-dimensional adsorption behaviors and microcosmic action mechanism performance; 4, analyzing a competitive adsorption mechanism in a complex environment system; the bamboo wood is used as the raw material, the agricultural and forestry waste is used for preparing the activated carbon, the environment-friendly concept of treating waste with waste is met, and by optimizing the carbonization and activation process, the specific surface area and the pore uniformity are improved, and the adsorption performance is enhanced; according to the multi-pollutant cooperative treatment capacity, the adaptability to a complex pollution system is improved through the hydrophobic effect of surface functional groups (carboxyl and hydroxyl) and micro-plastics and the like in combination with electrostatic adsorption of magnetic particles.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bamboo-based magnetic activated carbon, and particularly relates to a method for preparing bamboo-based magnetic activated carbon and analyzing the adsorption capacity for microplastics. BACKGROUND

[0002] Industrial pollution problems are increasingly serious, and traditional activated carbon adsorption technology is facing a bottleneck due to high cost, non-renewable and other defects. Based on the carbon neutralization and material recycling trend, the majority of industrial production is committed to developing a method for activating waste biomass into activated carbon.

[0003] Studies have shown that bamboo-based activated carbon prepared from bamboo processing waste has a significant multi-level pore structure advantage, a higher specific surface area, and a pore structure mainly composed of micropores, as well as an appropriate amount of mesopores and macropores. This multi-level pore structure enables it to exhibit unique adsorption advantages for emerging pollutants such as microplastics in industrial wastewater. This dual value of converting biomass waste into pollution control materials is a typical practice of circular economy. Magnetic functionalization gives bamboo-based activated carbon a new dimension of performance improvement. The magnetic bamboo-based activated carbon (BMAC) constructed by loading magnetic particles such as Fe3O4 adds a new magnetic response characteristic on the basis of retaining the multi-level pore adsorption advantage: ① The magnetic separation efficiency reaches 98.5%, which is 62% lower in energy consumption than the traditional filtration method.

[0004] The preparation methods of bamboo-based activated carbon mainly include physical activation, chemical activation and mixed activation. The physical activation method usually uses high-temperature steam or carbon dioxide as the activator and is activated at 800-900℃. Studies have shown that the specific surface area of the obtained activated carbon can be as high as 1000-2000 m² / g. For example, in the study of Khuong et al., a kind of activated carbon with a specific surface area of 1496 m² / g was obtained by high-temperature activation hydrothermal treatment. The chemical activation method uses acid (such as boric acid), alkali (such as potassium hydroxide) or salt as the activator, which can obtain activated carbon with high specific surface area at lower temperature (400-700℃). The specific surface area of the bamboo-based magnetic activated carbon prepared by potassium hydroxide activation combined with microwave assisted method can reach 1764.03 m² / g, which is more conducive to the adsorption of microplastics. ２

[0005] In summary, there is an urgent need for a low-cost bamboo-based magnetic activated carbon to promote "waste treatment with waste", realize high-value utilization of biomass waste, and study the influence mechanism of the surface chemical properties of microplastics (such as oxidation degree and aging state) on adsorption selectivity. SUMMARY

[0006] To solve the problems mentioned in the background art, the purpose of the present application is to provide a method for preparing bamboo-based magnetic activated carbon and analyzing the adsorption capacity for microplastics.

[0007] ​The application discloses a method for preparing bamboo-based magnetic activated carbon and analyzing adsorption capacity of microplastics.

[0008] Step one: preparing high-performance bamboo-based magnetic activated carbon adsorption material:

[0009] By systemically regulating the bamboo-based magnetic activated carbon, a carbonization-activation coupling process in the preparation process is adopted, optimal carbonization-activation combination parameters are obtained, and the adsorption performance is improved by loading magnetic Fe3O4.

[0010] Step two: analyzing bamboo-based magnetic activated carbon and microplastic characteristics:

[0011] 2.1, the potential influence of the physical and chemical characteristics of the bamboo-based magnetic activated carbon such as micro-morphology, specific surface area and surface functional groups on adsorption is studied, SEM-EDS composite detection, BET specific surface area analysis and VSM magnetism test are adopted, and the pore grading structure, magnetic particle load distribution and surface functional group composition of the BMAC are analyzed; through XPS and Zeta potential determination, the surface charge characteristics and chemical active sites of the material are quantitatively characterized; combined with molecular dynamics simulation, a three-dimensional adsorption field model of the pore-magnetic core synergistic effect is established;

[0012] 2.2, typical microplastics are selected, the surface roughness, hydrophobicity and functional group distribution characteristics of the microplastics are analyzed and systematically characterized by means of STM, and orthogonal experiment analysis is carried out; XPS and other depth analysis techniques are adopted to explore the chemical structure evolution law caused by the surface aging process of the microplastics;

[0013] Step three: analyzing multi-dimensional adsorption behavior and micro-mechanism performance: analyzing kinetics, thermodynamics and selectivity;

[0014] Step four: analyzing the competitive adsorption mechanism in a complex environment system:

[0015] 4.1, an orthogonal experiment is designed to study the synergistic influence mechanism under different environmental variables such as pH, ionic strength and DOM concentration; a surface complexation model is corrected to establish a description method of the electric layer-space steric effect; and a multi-factor response prediction model is developed;

[0016] 4.2, a ternary competitive system is constructed, XANES is adopted to analyze the interface element distribution characteristics; a molecular imprinting technology is adopted to modify the surface of the BMAC, and a trap structure with charge / size dual selective recognition function is designed.

[0017] As a preferred scheme: the typical microplastics in the step two are polyethylene (PE) and polypropylene (PP) typical microplastics.

[0018] As a preferred scheme: the kinetics in the step three: through the intermittent adsorption experiment, the adsorption capacity of polyethylene (PE), polypropylene (PP) and the like microplastics on the BMAC is determined with the change curve of time, the equilibrium time is recorded, the quasi-first order, quasi-second order kinetic model and the intraparticle diffusion model are combined, and the adsorption rate control step is identified.

[0019] As a preferred scheme: the thermodynamics in the step three: the equilibrium adsorption capacity of the microplastics is determined in the temperature range of 283-323 K, the Langmuir, Freundlich and Sips model fitting are combined, the adsorption characteristics are analyzed, the monolayer / multilayer adsorption dominant mode is determined, the isosteric heat of adsorption is calculated through the Clausius-Clapeyron equation, and the spontaneity and driving force type of the adsorption process are determined through the Van't Hoff curve.

[0020] As a preferred scheme: the selectivity in the step three: the relationship between the surface hydrophobicity, the polar functional group density of the microplastics and the BMAC adsorption efficiency is induced through the multiple regression model, the key parameters of the dominant selective adsorption are screened, and the matching relationship between the key parameters and the material characteristics is explored.

[0021] As a preferred scheme: the key parameters are the pore size matching degree and the electrostatic potential distribution parameters.

[0022] As a preferred scheme: the ternary competitive system is a heavy metal-organic pollutant-microplastic ternary competitive system.

[0023] Compared with the prior art, the present application has the beneficial effects that:

[0024] 1. The present application uses bamboo as a raw material to prepare activated carbon from agricultural and forestry wastes, which conforms to the environmental protection concept of "waste treatment with waste"; by optimizing the carbonization and activation process, the specific surface area and pore uniformity are improved, and the adsorption performance is enhanced.

[0025] 2. The multi-pollutant synergistic treatment capacity of the present application: through the hydrophobic effect of the surface functional groups (carboxyl, hydroxyl) and the microplastics, and the electrostatic adsorption of the magnetic particles, the adaptability to complex pollution systems is improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to facilitate the description, the present application is described in detail by the following specific embodiments and drawings.

[0027] Figure 1 The present application is a structural schematic diagram. DETAILED DESCRIPTION

[0028] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described below by means of specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. The structures, proportions, sizes, etc. shown in the drawings of the present specification are only used to cooperate with the content disclosed in the present specification for understanding and reading by those skilled in the art, and are not intended to limit the defined conditions under which the present application can be implemented, so they do not have substantial technical significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0029] It should also be noted here that, in order to avoid obscuring the present application due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present application are shown in the drawings, and other details not closely related to the present application are omitted.

[0030] In combination Figure 1 The present embodiment is illustrated by the following technical solutions:

[0031] Step one: preparation of high-performance bamboo-based magnetic activated carbon adsorption material:

[0032] By systemically regulating the bamboo-based magnetic activated carbon, the carbonization-activation coupling process in the preparation process is obtained, the best carbonization-activation combination parameters are obtained, and the adsorption performance is improved by loading magnetic Fe3O4;

[0033] Step two: analysis of the characteristics of bamboo-based magnetic activated carbon and microplastics:

[0034] 2.1, study the potential influence of the physical and chemical properties of bamboo-based magnetic activated carbon such as micro-morphology, specific surface area and surface functional groups on adsorption, adopt SEM-EDS composite detection, BET specific surface area analysis, VSM magnetic testing and other means to analyze the pore grading structure, magnetic particle load distribution and surface functional group composition of BMAC; through XPS and Zeta potential determination, the surface charge characteristics and chemical active sites of the material are quantitatively characterized; combined with molecular dynamics simulation, a three-dimensional adsorption field model of pore-magnetic core synergistic effect is established;

[0035] 2.2, select typical microplastics, such as polyethylene (PE) and polypropylene (PP), analyze and systematically characterize the surface roughness, hydrophobicity and functional group distribution characteristics of the typical microplastics by means of STM, and perform orthogonal experiment analysis; use XPS and other depth profiling techniques to explore the chemical structure evolution law caused by the surface aging process of microplastics;

[0036] Step 3: Analyze multi-dimensional adsorption behavior and microscopic mechanisms: analyze kinetics, thermodynamics, and selectivity;

[0037] The kinetics are as follows: Through intermittent adsorption experiments, the adsorption capacity of microplastics such as polyethylene (PE) and polypropylene (PP) on BMAC is measured as a function of time, the equilibrium time is recorded, and the adsorption rate control steps are identified by combining pseudo-first-order and pseudo-second-order kinetic models and intraparticle diffusion models.

[0038] The thermodynamics involved determining the equilibrium adsorption capacity of microplastics within a temperature range of 283-323 K, and analyzing the adsorption characteristics by fitting the Langmuir, Freundlich, and Sips models to identify the dominant monolayer / multilayer adsorption mode. The isotropic heat of adsorption was calculated using the Clausius-Clapeyron equation, and the spontaneity and driving force of the adsorption process were determined by combining the Van't Hoff curve.

[0039] The selectivity is described as follows: through a multiple regression model, the relationship between the surface hydrophobicity of microplastics, the density of polar functional groups and the BMAC adsorption efficiency is summarized, the key parameters that dominate selective adsorption are screened, and their matching relationship with material properties is explored. The key parameters are the pore size matching degree and the electrostatic potential distribution.

[0040] Step 4: Analyze the competitive adsorption mechanism in complex environmental systems:

[0041] 4.1 Design orthogonal experiments to study the synergistic influence mechanism under different environmental variables such as pH, ionic strength, and DOM concentration; establish a descriptive method for the electric layer-steric hindrance effect through surface complexation model modification; and develop a multi-factor response prediction model.

[0042] 4.2 Construct a ternary competitive system and use XANES to analyze the distribution characteristics of interface elements; use molecular imprinting technology to directionally modify the BMAC surface and design a trap structure with charge / size dual selective recognition function. The ternary competitive system is a heavy metal-organic pollutant-microplastic ternary competitive system.

[0043] Step 5: Study the adaptability for engineering applications:

[0044] 5.1 Real-world water validation platform: Build a dynamic simulation system containing complex components such as suspended particulate matter, oily substances, and microbial films to evaluate the adsorption flux decay law of BMAC under continuous operating conditions; conduct DSC tests, develop a magnetic separation-regeneration system, and analyze and determine the optimal thermal regeneration temperature and cycle stability.

[0045] 5.2 Ecological compatibility: Detect the leaching amount of magnetic particles (Fe3O4), establish an environmental risk assessment system, analyze the environmental risks of magnetic particles or activated carbon residues during material use, and optimize the balance between material dosage and operating energy consumption.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0047] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing bamboo-based magnetic activated carbon and analyzing the adsorption capacity for microplastics, characterized in that: The method is as follows: Step one: preparation of high-performance bamboo-based magnetic activated carbon adsorption material: Through systematic regulation of bamboo-based magnetic activated carbon, the optimal carbonization-activation combination parameters are obtained in the preparation process, and the adsorption performance is improved by loading magnetic Fe3O4. Step two: analysis of the characteristics of bamboo-based magnetic activated carbon and microplastics: 2.1, study the potential influence of the micro-morphology, specific surface area, and surface functional group physical and chemical characteristics of bamboo-based magnetic activated carbon on adsorption, use SEM-EDS composite detection, BET specific surface area analysis, and VSM magnetic testing means to analyze the pore classification structure, magnetic particle load distribution, and surface functional group composition of BMAC; through XPS and Zeta potential measurement, the surface charge characteristics and chemical active sites of the material are quantitatively characterized; combined with molecular dynamics simulation, a three-dimensional adsorption field model of pore-magnetic core cooperation is established; 2.2, select typical microplastics, analyze and systematically characterize their surface roughness, hydrophobicity, and functional group distribution characteristics through STM means, and perform orthogonal experiment analysis; use XPS depth profiling technology to explore the chemical structure evolution law caused by the surface aging process of microplastics; Step three: analysis of multi-dimensional adsorption behavior and micro-mechanism performance: analysis of kinetics, thermodynamics, and selectivity; Step four: analysis of competitive adsorption mechanism in complex environmental system: 4.1, design orthogonal experiment to study the synergistic effect mechanism under different pH, ionic strength, and DOM concentration environmental variables; Through surface complexation model correction, a description method of electric layer-space steric effect is established; a multi-factor response prediction model is developed; 4.2, construct a ternary competitive system, use XANES to analyze the interface element distribution characteristics; use molecular imprinting technology to modify the surface of BMAC, and design a trap structure with charge / size dual selective recognition function.

2. The method for preparing bamboo-based magnetic activated carbon and analyzing the adsorption capacity for microplastics according to claim 1, characterized in that: The typical microplastics in step two are polyethylene and polypropylene typical microplastics.

3. The method for preparing bamboo-based magnetic activated carbon and analyzing its adsorption capacity for microplastics according to claim 1, characterized in that: The kinetics in step three: through intermittent adsorption experiment, the adsorption capacity of polyethylene and polypropylene microplastics on BMAC changes with time, the equilibrium time is recorded, and the adsorption rate control step is identified by combining the pseudo-first-order, pseudo-second-order kinetic model and the intra-particle diffusion model.

4. The method for preparing bamboo-based magnetic activated carbon and analyzing the adsorption capacity for microplastics according to claim 1, characterized in that: The thermodynamics in step three: in the temperature range of 283-323 K, the equilibrium adsorption capacity of microplastics is measured, the Langmuir, Freundlich and Sips models are fitted, the adsorption characteristics are analyzed, and the single / multi-layer adsorption dominant mode is determined; the heat of adsorption is calculated by Clausius-Clapeyron equation, and the spontaneity and driving force type of the adsorption process are determined by Van't Hoff curve.

5. The method for preparing bamboo-based magnetic activated carbon and analyzing its adsorption capacity for microplastics according to claim 1, characterized in that: The selectivity in step three: through multiple regression model, the relationship between the surface hydrophobicity, polar functional group density of microplastics and the adsorption efficiency of BMAC is summarized, the key parameters of dominant selective adsorption are selected, and the matching relationship between them and material characteristics is explored.

6. The method for preparing bamboo-based magnetic activated carbon and analyzing the adsorption capacity for microplastics according to claim 5, characterized in that: The key parameters are pore size matching degree and electrostatic potential distribution parameters.

7. The method for preparing bamboo-based magnetic activated carbon and analyzing its adsorption capacity for microplastics according to claim 1, characterized in that: The ternary competitive system is a heavy metal-organic pollutant-microplastic ternary competitive system.

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