Solid waste-based metal-organic framework derived porous carbon nanomaterial as well as preparation method and application thereof
By preparing solid waste-based metal-organic frame-derived porous carbon nanomaterials, the problems of poor transmission and migration capabilities, excessive activity and expensive catalytic materials in the prior art are solved, and efficient, green and low-cost soil repair technology is achieved , has excellent catalytic oxidation properties and dispersion.
Patent Information
- Application Number
- CN202411517820.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-02-14
AI Technical Summary
The heterogeneous catalytic materials used in the prior art have poor transmission and migration capabilities, excessive material activity and high price, which limit their use and promotion in in-situ soil groundwater environments.
Porous carbon nanomaterials are derived using solid waste-based metal-organic frames. This material is alkaline-heat activation of solid waste-based gelling material powder containing aluminum ions and iron ions, combined with microplastics and acid solutions for heating, and then with the The nitrogen compounds and sulfur-containing compounds were subjected to calcination and smoldering treatment to prepare nanomaterials with excellent catalytic oxidation properties and dispersion.
It realizes high-efficiency, green, low-soil damage and low-cost in-situ advanced oxidation repair technology, which can effectively remove organic pollutants in the soil, and bind residual pollutants through functional groups on the surface to reduce the leaching of sulfate ions in the soil. It has continuous stability function.
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Figure CN119430128A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of functional materials for soil remediation projects, and in particular, relates to a solid waste-based metal-organic framework-derived porous carbon nanomaterial and a preparation method and application thereof. Background Art
[0002] In the past decade, with the rapid economic development, a series of environmental pollution problems have inevitably been caused. According to incomplete statistics, there are more than 500,000 contaminated sites with an area of more than 10,000 square meters in my country, and the phenomenon of excessive organic pollutants is prominent. With the development of the economy and society, the remediation of contaminated sites has received more and more attention, and the treatment and remediation of organic contaminated soil has also ushered in new development opportunities. The new situation has put forward higher requirements for the development of contaminated site remediation technology in my country. The State Council's "Action Plan for Soil Pollution Prevention and Control" clearly requires that pollution control and remediation should be actively carried out, and in-situ remediation control should be actively carried out in the control and remediation projects.
[0003] For the remediation of organic contaminated soil, the existing technology usually adopts in-situ advanced chemical oxidation technology, that is, using advanced oxidants, such as persulfate (PS) and peroxymonosulfate (PMS), etc., under the action of heterogeneous iron-based catalysts (such as iron-containing minerals, metal (iron)-organic frameworks, nano zero-valent iron, etc.), to efficiently and slowly oxidize and decompose organic pollutants in the soil to solve the pollution problem. For example, some scholars have carried out experiments to analyze the efficiency of nano-iron catalytic degradation of petroleum hydrocarbon contaminated soil, and some scholars have explored the feasibility of nano-scale zero-valent iron-nickel bimetallic loaded biochar to degrade chlorinated hydrocarbon pollution. However, efficient heterogeneous catalytic materials represented by zero-valent nano-iron have problems such as high price, extremely strong material activity and poor transmission and migration capacity, which limits the use and promotion of this catalytic oxidation technology in in-situ soil and groundwater environments.
[0004] Therefore, there is an urgent need to develop a functional material with strong oxidizing properties to achieve efficient, green, low soil damage and low-cost in-situ advanced oxidation remediation technology to better deal with complex and difficult organic pollution problems and organic pollution tail effects. Summary of the invention
[0005] The purpose of this application is to provide a solid waste-based metal-organic framework-derived porous carbon nanomaterial and its preparation method and application, aiming to solve the problems of poor transmission and migration capacity, excessive material activity and high price of heterogeneous catalytic materials used in the prior art.
[0006] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:
[0007] In a first aspect, the present application provides a method for preparing a solid waste-based metal-organic framework-derived porous carbon nanomaterial, comprising the following steps:
[0008] Providing solid waste-based gelling material powder containing aluminum ions and iron ions, and performing alkaline thermal activation on the solid waste-based gelling material powder to obtain a metal precursor;
[0009] The metal precursor, microplastics and acid solution are mixed and then heated to react to obtain metal-organic framework nanomaterials;
[0010] The metal-organic framework nanomaterial is mixed with a nitrogen-containing compound and a sulfur-containing compound to obtain a mixture, which is then subjected to a calcination treatment; and then subjected to a smoldering treatment to obtain a solid waste-based metal-organic framework-derived porous carbon nanomaterial.
[0011] In some embodiments, the step of providing a solid waste-based cementitious material powder containing aluminum ions and iron ions comprises:
[0012] The fly ash and converter slag are sequentially dried, crushed and sieved to obtain fly ash powder and converter slag powder, wherein the fly ash contains no less than 30% aluminum and the converter slag contains no less than 35% iron;
[0013] According to the molar ratio of Al:Fe being 1:(0.8-1.2), fly ash powder and steel slag powder are weighed and mixed evenly to obtain solid waste-based cementitious material powder containing aluminum ions and iron ions.
[0014] In some embodiments, the temperature of the alkali thermal activation is 850° C. to 950° C., and the time is 1 to 2 hours.
[0015] In some embodiments, the microplastics are selected from PET microplastics with a particle size less than 150 μm, and the mass ratio of the metal precursor to the microplastics is 1:1 to 1.1.
[0016] In some embodiments, the acid solution is selected from a hydrochloric acid solution with a concentration of 1 to 1.2 mmol / L, and the mass ratio of the total mass of the metal precursor and microplastics to the acid solution is 1:8 to 12.
[0017] In some embodiments, the heating reaction is carried out at a temperature of 220 to 230° C. and for a time of 6 to 10 hours.
[0018] In some embodiments, the nitrogen-containing compound is selected from NaNH 2 ,CON 2 H 4 , and the mass of the nitrogen-containing compound accounts for 2% to 2.5% of the mass of the metal-organic framework nanomaterial.
[0019] In some embodiments, the sulfur-containing compound is selected from Na 2 S 2 O 3 、Na 2 S 2 O8 , sublimated sulfur, and the mass of the sulfur-containing compound accounts for 3% to 3.5% of the mass of the metal-organic framework nanomaterial.
[0020] In some embodiments, the calcination step includes: providing a protective gas atmosphere, heating the mixture from room temperature to 100-105°C at a heating rate of 2-2.5°C / min, and then heating the mixture to 800-805°C at a heating rate of 10-10.5°C / min for calcination for 1-1.2 hours.
[0021] In some embodiments, the smoldering treatment step includes: providing an air atmosphere, cooling the temperature to 500-520° C. for smoldering treatment for 40-60 minutes, and then cooling to room temperature.
[0022] In a second aspect, the present application provides a solid waste-based metal-organic framework derived porous carbon nanomaterial prepared by the above-mentioned method for preparing a solid waste-based metal-organic framework derived porous carbon nanomaterial.
[0023] In a third aspect, the present application provides the application of solid waste-based metal-organic framework-derived porous carbon nanomaterials in the remediation of organically contaminated soil.
[0024] The preparation method of the solid waste-based metal-organic framework derived porous carbon nanomaterial provided in the first aspect of the present application is to mix the main material of the solid waste-based gelling material powder containing aluminum ions and iron ions with the organic ligand material of microplastics, and then freely generate them on the solid waste-based gelling material powder matrix to obtain Al / Fe-MOF@ash, which not only realizes the use of all solid waste precursors and ligands in the material synthesis process, but also realizes the effective dispersion and binding of active nanomaterials (Al / Fe-MOF); further nitrogen-sulfur hybridization and graphitization treatment are carried out to realize that the material surface has a richer functional group composition, and provide a high specific surface area reaction carrier and place for the Al / Fe-MOF material activation and oxidation of organic pollutants; so that the obtained solid waste-based metal-organic framework derived porous carbon nanomaterial has a strong oxidation effect and excellent dispersibility. The preparation method can realize the use of solid waste-based gelling materials to the greatest extent, and the preparation cost is low, the preparation process is simple, and no large instruments and equipment are required, which is conducive to industrial application.
[0025] The second aspect of the present application provides a solid waste-based metal-organic framework derived porous carbon nanomaterial, which is prepared by the above-mentioned preparation method. The porous structure formed by the solid waste-based metal-organic framework derived porous carbon nanomaterial can provide a reaction carrier and place with a high specific surface area for the reactants, and can exert the maximum oxidation effect to remove organic pollutants during the reaction, and has excellent catalytic oxidation function; and, it has excellent use dispersibility, can effectively avoid accumulation in the in-situ strata, improve the decomposition and repair efficiency of the oxidant, and effectively weaken the local tailing effect formed during the repair process; at the same time, it uses solid waste-based gelling material as the matrix, has low production cost, and effectively reduces the cost of pure phase catalytic materials represented by nano-iron used in traditional in-situ chemical oxidation repair processes; it is conducive to wide use.
[0026] The third aspect of the present application provides an application of solid waste-based metal-organic framework-derived porous carbon nanomaterials in the repair of organic contaminated soil. The solid waste-based metal-organic framework-derived porous carbon nanomaterials obtained by the above-mentioned preparation method are used. The obtained solid waste-based metal-organic framework-derived porous carbon nanomaterials have excellent catalytic oxidizing properties and usability dispersion. In the application of repairing organic contaminated soil, the material can achieve efficient removal of organic pollutants in the soil, and can also effectively bind some residual organic pollutants, organic intermediates and oxidized residual sulfate ions through bonding with rich functional groups on the surface, thereby achieving functional treatment and fixation of organic pollutants, reducing the leaching of residual sulfate ions in the soil, and achieving the solid waste-based metal-organic framework-derived porous carbon nanomaterials remaining in the soil environment. The porous carbon nanomaterials can play a continuous stabilization function on the soil; and the cost of the material is low, which solves the problem that nanocatalytic materials cannot be effectively recovered in traditional soil remediation processes, and can be widely used in the repair of organic contaminated soil. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0028] Figure 1 This is a SEM image of the solid waste-based metal-organic framework derived porous carbon nanomaterial provided in Example 1 of the present application.
[0029] Figure 2 This is the EDS image of the solid waste-based metal-organic framework derived porous carbon nanomaterial provided in Example 1 of the present application.
[0030] Figure 3These are the test results of the remediation efficiency of organic contaminated soil using the materials of Example 1, Comparative Example 1 and Comparative Example 2 combined with PMS. DETAILED DESCRIPTION
[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0032] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.
[0033] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.
[0034] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.
[0035] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.
[0036] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass in the embodiment description of the present application can be μg, mg, g, kg and other mass units known in the chemical industry.
[0037] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features.
[0038] The first aspect of the embodiment of the present application provides a method for preparing a solid waste-based metal-organic framework-derived porous carbon nanomaterial, comprising the following steps:
[0039] S01. Providing a solid waste-based gelling material powder containing aluminum ions and iron ions, and performing alkaline thermal activation on the solid waste-based gelling material powder to obtain a metal precursor;
[0040] S02. mixing the metal precursor, microplastics and acid solution and then heating them to react to obtain a metal-organic framework nanomaterial;
[0041] S03. Mix the metal-organic framework nanomaterial with a nitrogen-containing compound and a sulfur-containing compound to obtain a mixture, and then perform a calcination treatment; and then perform a smoldering treatment to obtain a solid waste-based metal-organic framework-derived porous carbon nanomaterial.
[0042] The preparation method of the solid waste-based metal-organic framework derived porous carbon nanomaterial provided in the first aspect of the embodiment of the present application is to mix the main material of the solid waste-based gelling material powder containing aluminum ions and iron ions with the organic ligand material of microplastics, and then freely generate on the solid waste-based gelling material powder matrix to obtain Al / Fe-MOF@ash, which not only realizes the use of all solid waste precursors and ligands in the material synthesis process, but also realizes the effective dispersion and binding of active nanomaterials (Al / Fe-MOF); further nitrogen-sulfur hybridization and graphitization treatment are carried out to realize that the material surface has a richer functional group composition, and provide a high specific surface area reaction carrier and place for the Al / Fe-MOF material activation and oxidation of organic pollutants; so that the obtained solid waste-based metal-organic framework derived porous carbon nanomaterial has a strong oxidation effect and excellent dispersibility. The preparation method can realize the use of solid waste-based gelling materials to the greatest extent, and the preparation cost is low, the preparation process is simple, and no large instruments and equipment are required, which is conducive to industrial application.
[0043] In step S01, solid waste-based gelling material powder containing aluminum ions and iron ions is provided, and the solid waste-based gelling material powder is subjected to alkaline thermal activation to obtain a metal precursor.
[0044] In some embodiments, the step of providing a solid waste-based cementitious material powder containing aluminum ions and iron ions comprises:
[0045] S011. The fly ash and converter slag are sequentially dried, crushed and sieved to obtain fly ash powder and converter slag powder, wherein the fly ash contains not less than 30% aluminum and the converter slag contains not less than 35% iron;
[0046] S012. According to the molar ratio of Al:Fe being 1:(0.8-1.2), fly ash powder and steel slag powder are weighed and mixed evenly to obtain solid waste-based cementitious material powder containing aluminum ions and iron ions.
[0047] In step S011, the fly ash and converter slag are dried, crushed and sieved in sequence to obtain fly ash powder and converter slag powder, wherein the aluminum content in the fly ash is not less than 30%, and the iron content in the converter slag is not less than 35%.
[0048] In some embodiments, the solid waste fly ash and converter slag used were tested by XRF, and the main components and mass percentages are shown in Table 1. The fly ash provided mainly provides aluminum element precursor material for the overall reaction process, while the converter slag mainly provides an alkaline activation environment and iron elements to embed into the precursor.
[0049] Table 1
[0050]
[0051] In some embodiments, the fly ash and converter slag are first dried, and the main reason for the drying is to remove the moisture therein for further processing and utilization. In some specific embodiments, a drying machine is provided for drying, and the drying temperature generally used is 105° C. and the time is 16 hours.
[0052] Furthermore, the dried material is crushed to obtain small particles of material for the convenience of subsequent reactions.
[0053] Further, the crushed material is sieved to ensure that the powder particles are uniform in size. In some specific embodiments, a sieve with an aperture of 75 μm is selected for sieving to obtain fly ash powder and converter slag powder.
[0054] In step S012, fly ash powder and steel slag powder are weighed and mixed evenly according to the molar ratio of Al:Fe being 1:(0.8-1.2) to obtain solid waste-based cementitious material powder containing aluminum ions and iron ions. The molar ratio of Al:Fe is controlled to be 1:(0.8-1.2) in order to form a prismatic three-dimensional MOF structure embedded with Al and Fe ions.
[0055] In some embodiments, the molar ratio of Al:Fe includes, but is not limited to, any typical but non-limiting point values such as 1:0.8, 1:0.85, 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1, 1:1.15, 1:1.2, or an interval value between any two point values.
[0056] Furthermore, the solid waste-based gelling material powder is subjected to alkaline thermal activation to obtain a metal precursor. Since converter slag is alkaline, it provides an alkaline environment for the activation reaction; heat treatment under alkaline conditions causes the solid waste-based gelling material powder to undergo a specific melting reaction to obtain an ionic chemical with active properties, which can be used as a metal precursor for subsequent experiments.
[0057] In some embodiments, the temperature of alkali thermal activation is 850°C to 950°C, and the time is 1 to 2 hours. If the temperature of alkali thermal activation is too low, the solid waste-based gelling material powder will not be effectively activated, resulting in the inability to form an active metal precursor; if the temperature is too high, the production process will generate a large amount of additional carbon emissions and energy consumption. In some specific embodiments, the temperature of alkali thermal activation includes but is not limited to 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C, 950°C, etc., typical but non-limiting arbitrary point values or interval values between any two point values. The time of alkali thermal activation includes but is not limited to 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2 hours, etc., typical but non-limiting arbitrary point values or interval values between any two point values.
[0058] In step S02, the metal precursor, microplastics and acid solution are mixed and then heated to react to obtain a metal-organic framework nanomaterial.
[0059] In some embodiments, the microplastics are selected from PET microplastics with a particle size of less than 150 μm. The PET microplastics are used as organic ligand materials to react with metal precursors to obtain metal-organic framework nanomaterials containing Fe and Al elements. The use of all-solid waste precursors and ligands in the material synthesis process reduces the high cost problem caused by the use of pure phase chemical substances in the traditional process. In addition, the solid waste-based iron-aluminum metal-organic framework (Al / Fe-MOF) grows on a fly ash-steel slag residue matrix (Al / Fe-MOF@ash), which achieves effective dispersion and binding of active nanomaterials (Al / Fe-MOF), while the traditional Al / Fe-MOF materials synthesized from pure phase substances are easy to agglomerate, which is not conducive to dispersion in the soil and is not conducive to the remediation of soil system pollution.
[0060] Among them, the particle size of the PET microplastic provided is less than 150μm to better form an organic framework.
[0061] In some embodiments, the mass ratio of the metal precursor to the microplastic is 1:1 to 1.1. In some specific embodiments, the mass ratio of the metal precursor to the microplastic is selected from 1:1.
[0062] Further, an acid solution is provided as a base solution. In some embodiments, the acid solution is selected from a hydrochloric acid solution with a concentration of 1 to 1.2 mmol / L, and the mass ratio of the total mass of the metal precursor and the microplastic to the acid solution is 1:8 to 12. Among them, the mass ratio of the total mass of the metal precursor and the microplastic to the acid solution is controlled to be 1:8 to 12, the purpose of which is to provide sufficient water environment guarantee for the hydrothermal reaction of the metal precursor and the microplastic, so that the substances can fully contact and react in the water environment.
[0063] In some embodiments, the temperature of the hydrothermal reaction is 220-230°C and the time is 6-10 hours. The heating reaction is mainly to obtain metal-organic framework nanomaterials. If the temperature of the heating reaction is too low, Al / Fe-MOF@ash with good environmental performance will not be formed; if the temperature is too high, the pressure in the hydrothermal reaction will increase rapidly, causing an explosion risk. In some specific embodiments, the temperature of the hydrothermal reaction includes but is not limited to 220°C, 221°C, 222°C, 223°C, 224°C, 225°C, 226°C, 227°C, 228°C, 229°C, 230°C, and other typical but non-limiting arbitrary point values or interval values between any two point values. The time of the hydrothermal reaction includes but is not limited to 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, and other typical but non-limiting arbitrary point values or interval values between any two point values.
[0064] In some embodiments, after the heating reaction is completed, filtering, washing, and drying are also performed.
[0065] In step S03, the metal-organic framework nanomaterial is mixed with a nitrogen-containing compound and a sulfur-containing compound to obtain a mixture, which is then subjected to a calcination treatment; and then subjected to a smoldering treatment to obtain a solid waste-based metal-organic framework-derived porous carbon nanomaterial.
[0066] In some embodiments, the nitrogen-containing compound is selected from NaNH 2 ,CON 2 H 4 Providing nitrogen-containing compounds to perform nitrogen hybridization treatment on metal-organic framework nanomaterials.
[0067] In some embodiments, the mass of the nitrogen-containing compound accounts for 2% to 2.5% of the mass of the metal-organic framework nanomaterial. In some specific embodiments, the mass of the nitrogen-containing compound accounts for, but is not limited to, 2%, 2.1%, 2.2%, 2.3%, 2.4%, and 2.5% of the mass of the metal-organic framework nanomaterial.
[0068] In some embodiments, the sulfur-containing compound is selected from Na 2 S 2 O 3 、Na 2 S 2 O 8 , subliming sulfur, etc. Provide sulfur-containing compounds to carry out sulfur hybridization treatment on metal-organic framework nanomaterials.
[0069] In some embodiments, the mass of the sulfur-containing compound accounts for 3% to 3.5% of the mass of the metal-organic framework nanomaterial. In some specific embodiments, the mass of the nitrogen-containing compound accounts for, but is not limited to, 3%, 3.1%, 3.2%, 3.3%, 3.4%, and 3.5% of the mass of the metal-organic framework nanomaterial.
[0070] Furthermore, a calcination treatment is performed.
[0071] In some embodiments, the calcination step includes: providing a protective gas atmosphere, heating the mixture from room temperature to 100-105°C at a heating rate of 2-2.5°C / min, and then heating the mixture to 800-805°C at a heating rate of 10-10.5°C / min for calcination for 1-1.2 hours.
[0072] In some specific embodiments, after the various substances are mixed evenly, they are placed in a tubular furnace, and under nitrogen protection, the temperature is first increased from room temperature to 100°C at a heating rate of 2°C / min, and then increased from 100°C to 800°C at a heating rate of 10°C / min, and calcined for 1 hour.
[0073] Solid waste-based metal-organic framework nanomaterials containing Fe and Al elements are nitrogen-sulfurized and graphitized. This treatment process can achieve a richer functional group composition on the material surface and provide a high specific surface area reaction carrier and site for the Al / Fe-MOF material to activate oxidants represented by PMS and oxidize organic pollutants.
[0074] Furthermore, smoldering treatment is performed. Smoldering treatment is to inject air into the reactants, ignite them under low energy conditions to cause slow self-sustaining combustion of the reactants, and then use the combustion heat of the reactants themselves to cause continuous combustion in the surrounding contaminated areas. Under the condition of maintaining air supply, the combustion can continue and spread to the entire reaction area, and the combustion and temperature are controlled by air.
[0075] In some embodiments, the smoldering treatment step includes: providing an air atmosphere, cooling the temperature to 500-520° C. for smoldering treatment for 40-60 minutes, and then cooling to room temperature.
[0076] In some specific embodiments, the temperature of the smoldering treatment includes, but is not limited to, any typical but non-limiting point value or an interval value between any two point values, such as 500° C., 505° C., 510° C., 515° C., 520° C., etc. The time of the smoldering treatment includes, but is not limited to, any typical but non-limiting point value or an interval value between any two point values, such as 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, etc.
[0077] A second aspect of an embodiment of the present application provides a solid waste-based metal-organic framework derived porous carbon nanomaterial prepared by the above-mentioned method for preparing a solid waste-based metal-organic framework derived porous carbon nanomaterial.
[0078] The second aspect of the embodiment of the present application provides a solid waste-based metal-organic framework derived porous carbon nanomaterial, and the provided solid waste-based metal-organic framework derived porous carbon nanomaterial is prepared by the above-mentioned preparation method. The porous structure formed by the solid waste-based metal-organic framework derived porous carbon nanomaterial can provide a reaction carrier and place with a high specific surface area for the reactants, and can exert the maximum oxidation effect to remove organic pollutants during the reaction, and has excellent catalytic oxidation function; and, it has excellent use dispersibility, can effectively avoid accumulation in the in-situ strata, improve the decomposition and repair efficiency of the oxidant, and effectively weaken the local tailing effect formed during the repair process; at the same time, it uses solid waste-based gelling material as the matrix, has low production cost, and effectively reduces the cost of pure phase catalytic materials represented by nano-iron used in traditional in-situ chemical oxidation repair processes; it is conducive to wide use.
[0079] A third aspect of the embodiments of the present application provides the application of solid waste-based metal-organic framework-derived porous carbon nanomaterials in the repair of organically contaminated soil.
[0080] The third aspect of the embodiment of the present application provides an application of solid waste-based metal-organic framework-derived porous carbon nanomaterials in the repair of organic contaminated soil. The solid waste-based metal-organic framework-derived porous carbon nanomaterials obtained by the above-mentioned preparation method are used. The obtained solid waste-based metal-organic framework-derived porous carbon nanomaterials have excellent catalytic oxidizing properties and usability dispersion. In the application of repairing organic contaminated soil, the material can achieve efficient removal of organic pollutants in the soil, and can also effectively bind some residual organic pollutants, organic intermediates and oxidized residual sulfate ions through bonding with rich functional groups on the surface, thereby achieving functional treatment and fixation of organic pollutants, reducing the leaching of residual sulfate ions in the soil, and achieving the solid waste-based metal-organic framework-derived porous carbon nanomaterials remaining in the soil environment. The porous carbon nanomaterials can play a continuous stabilization function on the soil; and the cost of the material is low, which solves the problem that nanocatalytic materials cannot be effectively recovered in traditional soil remediation processes, and can be widely used in the repair of organic contaminated soil.
[0081] In some embodiments, the use of solid waste-based metal-organic framework-derived porous carbon nanomaterials in the remediation of organic contaminated soil includes the following steps:
[0082] G01. Pre-treat the organic contaminated soil, control the moisture content of the organic contaminated soil to 30-35%, calculate the dry soil mass and test the concentration of organic pollutants;
[0083] G02. Add sodium persulfate or peroxymonosulfate to the organically contaminated soil, and then add the solid waste-based metal-organic framework-derived porous carbon material provided above, mix evenly, and let it stand to obtain the repaired soil.
[0084] Solid waste-based metal-organic framework-derived porous carbon nanomaterials can be added to organically contaminated soil. Through the catalytic oxidation function on their surface, they can efficiently catalyze oxidizing materials such as PMS. Compared with the heterogeneous catalytic materials used in existing in-situ advanced chemical oxidation technologies, this material can not only better catalyze oxidizing materials and maximize the oxidation effect to achieve efficient removal of organic pollutants in the soil, but also effectively bind some residual organic pollutants, organic intermediates and residual sulfate ions from oxidation through bonding with rich functional groups on the surface, thereby achieving functional treatment and fixation of organic pollutants, reducing the leaching of residual sulfate ions in the soil, and realizing the stabilization function of the repaired soil.
[0085] In step G01, the pretreatment step is mainly to remove obvious impurities such as stones, undecayed plants and animals, and to crush and mix the organically contaminated soil.
[0086] In step G02, in the step of adding sodium persulfate or peroxymonosulfate to the organic contaminated soil, the molar ratio of sodium persulfate or peroxymonosulfate to the organic pollutants in the organic contaminated soil is 10 to 50: 1. In some specific embodiments, the molar ratio of sodium persulfate or peroxymonosulfate to the organic pollutants in the organic contaminated soil includes, but is not limited to, any typical but non-limiting point values or interval values between any two point values such as 10: 1, 15: 1, 20: 1, 25: 1, 30: 1, 35: 1, 40: 1, 45: 1, 50: 1.
[0087] Further, the solid waste-based metal-organic framework-derived porous carbon material provided above is added. In some embodiments, the mass ratio of the solid waste-based metal-organic framework-derived porous carbon material to sodium persulfate or peroxymonosulfate is 1:(2-3). In some specific embodiments, the mass ratio of the solid waste-based metal-organic framework-derived porous carbon material to sodium persulfate or peroxymonosulfate includes but is not limited to 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3.0 and other typical but non-limiting arbitrary point values or interval values between any two point values.
[0088] The following describes the invention in conjunction with specific embodiments.
[0089] Example 1
[0090] A method for preparing a solid waste-based metal-organic framework-derived porous carbon nanomaterial comprises the following steps:
[0091] (1) Fly ash and converter slag are dried and ground respectively, and then passed through a 75 μm sieve to obtain fly ash powder and slag powder;
[0092] (2) according to the Al:Fe molar ratio of 1:1, fly ash powder and steel slag powder were weighed and mixed evenly, and the obtained mixed powder was placed in a muffle furnace and alkaline thermally activated at 900°C for 90 minutes to obtain a metal precursor;
[0093] (3) The metal precursor and PET microplastics with a particle size of less than 150 μm were mixed in a mass ratio of 1:1, and then added to a 1 mM hydrochloric acid solution at a solid-liquid ratio of 1:10, heated to 220°C for 8 h, filtered, and the precipitate was washed with deionized water and dried to obtain a metal-organic framework nanomaterial (Al / Fe-MOF@ash);
[0094] (4) Adding NaNH to metal-organic framework nanomaterials 2 and Na 2 S 2 O 3 (NaNH 2 and Na2 S 2 O 3 The addition amount accounts for 2% and 3% of the metal-organic framework nanomaterial mass respectively, and after being mixed evenly, they are placed in a tube furnace at 1m 3 / h flow of high-purity nitrogen, under nitrogen protection, first heated from room temperature to 100 ° C at a rate of 2 ° C / min, then heated from 100 ° C to 800 ° C at a rate of 10 ° C / min, calcined for 1 hour, and then heated at 2m / h. 3 An air flow was introduced at a flow rate of / h, cooled to 500°C in an air atmosphere, kept at the temperature for smoldering for 30 minutes, and finally cooled to room temperature to obtain a solid waste-based metal-organic framework-derived porous carbon nanomaterial, which was recorded as DMOF@NSP material.
[0095] Figure 1 This is a SEM image of the solid waste-based metal-organic framework-derived porous carbon nanomaterial prepared in Example 1, wherein: Figure 1 A and Figure 1 B is the SEM picture under different magnifications. It can be seen that the nanomaterial is composed of rich spherical substances (round fly ash residues after the reaction). The surface of the spherical substances is in situ grown and covered with rich needle-shaped, flaky Al / Fe-MOF and other nanomaterials. The rich spherical, needle-shaped, flaky and other substances can form a larger specific surface area and improve the efficiency of pollutant remediation.
[0096] right Figure 1 The SEM image of B was subjected to EDS analysis to obtain the EDS image of the solid waste-based metal-organic framework derived porous carbon material, see Figure 2 ,Depend on Figure 2 It can be seen that the material is mainly composed of C, O, Al, and Fe, among which C and O are the organic ligand skeletons of columnar and spherical materials. The columnar material is mainly an Al-based metal-organic framework structure, in which a small amount of Fe is inserted. The spherical material is an iron-containing nanomaterial generated by the reorganization and coupling of Fe-containing organic-metal frameworks and waste reaction residues under hydrothermal and carbonization.
[0097] Comparative Example 1
[0098] Preparation of pure phase Al / Fe-MOF materials: Al(NO 3 ) 3 9H 2 O and Fe(NO 3 ) 3 9H 2 O was mixed and dissolved in deionized water, and then terephthalic acid, Al(NO 3 ) 3 9H 2 O, Fe(NO 3 )3 9H 2 The molar ratio of O and terephthalic acid was 1:1:0.5, and the mixture was stirred for 1 hour and then placed in a high pressure reactor for reaction at 220°C for 10 hours to obtain a pure phase Al / Fe-MOF material. In Comparative Example 1, the raw materials used were all analytically pure chemicals.
[0099] Comparative Example 2
[0100] A commercially purchased zero-valent iron catalytic material was used as comparative example 2. The material was purchased from Beijing Xingrongyuan Technology Co., Ltd., with a purity of more than 98% and a particle size of 300 mesh (48 μm).
[0101] Application testing:
[0102] The solid waste-based metal-organic framework-derived porous carbon nanomaterial (DMOF@NSP) prepared in Example 1, the pure phase Al / Fe-MOF material prepared in Comparative Example 1, and the zero-valent iron catalytic material of Comparative Example 2 were applied to repair organic contaminated soil, and the method was as follows:
[0103] 1) Preparation of organic contaminated soil: The soil to be contaminated was sorted, large pieces of sand and gravel were sieved out, and the soil was crushed. The relevant physical and chemical indicators of the soil to be contaminated are shown in Table 2; diesel was added to the soil to represent petroleum hydrocarbon pollutants, and the pollution concentration was adjusted to 6500 mg / kg. The soil was evenly mixed and aged for six months to obtain petroleum hydrocarbon contaminated soil.
[0104] Table 2 Main physical and chemical indicators of uncontaminated soil used in the experiment
[0105]
[0106]
[0107] 2) The experiment set up four treatment groups, which were treated according to the following designs:
[0108] Control group: only PMS (peroxymonosulfate) was added, the addition amount was 180g / kg;
[0109] Example 1 treatment group: adding 180 g / kg of PMS + 60 g / kg of DMOF@NSP prepared in Example 1;
[0110] Comparative Example 1 treatment group: adding 180 g / kg of PMS + 60 g / kg of pure phase Al / Fe-MOF material prepared in Comparative Example 1;
[0111] Comparative Example 2 treatment group: adding 180 g / kg of PMS + 21 g / kg of the zero-valent iron catalytic material of Comparative Example 2;
[0112] Then water was added to control the moisture content in the organic contaminated soil to be around the liquid limit (the moisture content in this scheme was 32%), and then the soil was fully mixed at 23°C. The pollutant concentrations at 0h, 7h, 14h, 1d, 3d, 7d, 14d, 28d, 56d, and 90d were monitored to obtain the repaired soil. The repair rates of the four treatment groups that changed over time were calculated, and the amount of sulfate leaching remaining in the soil after repair was tested. The sulfate leaching test and calculation method in the soil sample referred to the international standard "Determination of water-soluble and acid-soluble sulfates" (ISO11048) and the U.S. EPA SOP I-1-42 standard to test the water-soluble sulfate leaching extraction content in the water environment (1:10 soil-water ratio).
[0113] Table 3 Repair efficiency test results of four treatment groups
[0114]
[0115] Figure 3 The test results of the remediation efficiency of organic contaminated soil using the materials of Example 1, Comparative Example 1 and Comparative Example 2 in combination with PMS are shown in Table 3 and Figure 3 It can be seen that the remediation rate curve of DMOF@NSP combined with PMS in Example 1 shows an extremely high remediation rate (>90%), and the final remediation node at 90h of the test is more than 30% higher than the remediation rates of Comparative Examples 1 and 2; the early rapid oxidation stage of organic matter in the remediation process of Comparative Example 2 is close to that of Example 1, but after 1h it enters a remediation fluctuation period, and the remediation rate does not increase significantly with time; in addition, the remediation agents used in Comparative Examples 1 and 2 are relatively expensive and are not easily mixed with contaminated soil, which will cause the remediation soil to have a large difference in residual concentration (the standard error of the test value is large).
[0116] Table 4 Water-soluble sulfate leaching content in soil after restoration
[0117]
[0118]
[0119] From the test data in Table 4, it can be found that the sulfate leaching value in the soil after repair in the control group and the comparative example 1 treatment group is not much different, indicating that the addition of these two repair agents will basically not have a blocking effect on the leaching of sulfate, far exceeding the 350 mg / L of groundwater Class IV in the Chinese Groundwater Quality Standard (GB T 14848-2017); and in the soil body repaired by the DMOF@NSP material of Example 1, the sulfate leaching value is very low. This is due to the stable and uniform occurrence of the DMOF@NSP material, and its rich functional groups and micro-nano pores on the surface can effectively capture sulfate ions, so that the sulfate in the soil can be stably present, reducing the risk of sulfate leaching threat to the soil groundwater. Therefore, the DMOF@NSP material proposed in the present invention has good environmental applicability.
[0120] In summary, the solid waste-based metal-organic framework-derived porous carbon nanomaterials prepared by the preparation method provided have strong oxidation effect and excellent dispersibility. In the application of repairing organic contaminated soil, the material can achieve efficient removal of organic pollutants in the soil, and can also effectively bind some residual organic pollutants, organic intermediates and oxidized residual sulfate ions through the bonding of rich functional groups on the surface, realize functional treatment and fixation of organic pollutants, reduce the leaching of residual sulfate ions in the soil, and realize that the solid waste-based metal-organic framework-derived porous carbon nanomaterials remaining in the soil environment can play a continuous stabilization function on the soil; and the cost of the material is low, which solves the problem that nanocatalytic materials cannot be effectively recovered in the traditional soil remediation process, and can be widely used in the repair of organic contaminated soil.
[0121] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims
1. A method for preparing a solid waste-based metal-organic framework-derived porous carbon nanomaterial, characterized in that: The steps include: Providing solid waste-based gelling material powder containing aluminum ions and iron ions, and performing alkali thermal activation on the solid waste-based gelling material powder to obtain a metal precursor; The metal precursor, microplastics and acid solution are mixed and then heated to react to obtain a metal-organic framework nanomaterial; The metal-organic framework nanomaterial is mixed with a nitrogen-containing compound and a sulfur-containing compound to obtain a mixture, which is then subjected to a calcination treatment; and then subjected to a smoldering treatment to obtain a solid waste-based metal-organic framework-derived porous carbon nanomaterial.
2. The method for preparing a solid waste-based metal-organic framework-derived porous carbon nanomaterial according to claim 1, characterized in that: The step of providing a solid waste-based gelling material powder containing aluminum ions and iron ions comprises: The fly ash and converter slag are sequentially dried, crushed and sieved to obtain fly ash powder and converter slag powder, wherein the fly ash contains no less than 30% aluminum and the converter slag contains no less than 35% iron; According to the molar ratio of Al:Fe being 1:(0.8-1.2), fly ash powder and steel slag powder are weighed and mixed evenly to obtain solid waste-based cementitious material powder containing aluminum ions and iron ions.
3. The method for preparing the solid waste-based metal-organic framework-derived porous carbon nanomaterial according to claim 1, characterized in that: The temperature of the alkali thermal activation is 850° C. to 950° C., and the time is 1 to 2 hours.
4. The method for preparing a solid waste-based metal-organic framework-derived porous carbon nanomaterial according to claim 1, characterized in that: The microplastics are selected from PET microplastics with a particle size of less than 150 μm, and the mass ratio of the metal precursor to the microplastics is 1:1 to 1.1; and / or, The acid solution is selected from a hydrochloric acid solution with a concentration of 1 to 1.2 mmol / L, and the mass ratio of the total mass of the metal precursor and the microplastic to the acid solution is 1:8 to 12.
5. The method for preparing solid waste-based metal-organic framework-derived porous carbon nanomaterial according to claim 1, characterized in that: The temperature of the heating reaction is 220-230° C. and the time is 6-10 hours.
6. The method for preparing a solid waste-based metal-organic framework-derived porous carbon nanomaterial according to claim 1, characterized in that: The nitrogen-containing compound is selected from any one of NaNH2 and CON2H4, and the mass of the nitrogen-containing compound accounts for 2% to 2.5% of the mass of the metal-organic framework nanomaterial; and / or, The sulfur-containing compound is selected from any one of Na2S2O3, Na2S2O8, and sublimated sulfur, and the mass of the sulfur-containing compound accounts for 3% to 3.5% of the mass of the metal-organic framework nanomaterial.
7. The method for preparing a solid waste-based metal-organic framework-derived porous carbon nanomaterial according to claim 1, characterized in that: The calcination step includes: providing a protective gas atmosphere, heating the mixture from room temperature to 100-105°C at a heating rate of 2-2.5°C / min, and then heating it to 800-805°C at a heating rate of 10-10.5°C / min for calcination for 1-1.2 hours.
8. The method for preparing a solid waste-based metal-organic framework-derived porous carbon nanomaterial according to claim 1, wherein the smoldering treatment step comprises: Provide air atmosphere, cool the temperature to 500-520°C, carry out smoldering treatment for 40-60 minutes, and then cool to room temperature.
9. A solid waste-based metal-organic framework derived porous carbon nanomaterial prepared by the method for preparing a solid waste-based metal-organic framework derived porous carbon nanomaterial according to any one of claims 1 to 8.
10. Use of the solid waste-based metal-organic framework-derived porous carbon nanomaterial as claimed in claim 9 in remediation of organic contaminated soil.