Preparation method and application of prussian blue-based composite thallium removal agent

Abstract

This invention discloses a method for preparing and applying a Prussian blue-based composite thallium removal agent, belonging to the field of environmental functional materials and wastewater treatment technology. Specifically, it relates to a Prussian blue-based nano-zero-valent iron composite material, comprising: a core layer comprising nano-zero-valent iron and Prussian blue-based material; and an outer layer comprising a composite layer of Prussian blue-based material analogues, wherein the Prussian blue-based material analogues include metal ions and ferrocyanide ions, and the metal ions include Fe. 2+ Fe 3+ Cu 2+ Ni 2+ Co 2+ and Zn 2+ At least one of the following. This invention provides a method for preparing and applying a Prussian blue-based composite thallium removal agent with good thallium ion adsorption performance, rapid solid-liquid separation via the magnetism of nZVI, and good regeneration performance.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional materials and wastewater treatment technology, specifically relating to a method for preparing and applying a Prussian blue-based composite thallium removal agent. Background Technology

[0002] Thallium is a highly toxic heavy metal that exists primarily as monovalent or trivalent ions in natural water bodies. Thallium exhibits strong bioaccumulation and neurotoxicity, and its uncontrolled release poses a serious threat to human health and the ecological environment.

[0003] Currently, treatment methods for thallium-contaminated water include chemical precipitation, ion exchange and adsorption, and coagulation. Chemical precipitation is suitable for removing high concentrations of thallium, but its effectiveness is limited for trace amounts. Ion exchange and adsorption methods can remove thallium at depths, but they are costly and complex to operate. Traditional coagulation processes are economical and practical, but when used alone, they are insufficient to reduce thallium concentrations below industrial wastewater discharge standards. Furthermore, existing technologies often rely on single treatment steps and lack synergistic mechanisms for dynamic adjustment based on water quality changes, leading to unstable treatment efficiency or high operating costs.

[0004] Therefore, developing a composite material that combines high adsorption capacity, good selectivity, and stability is of great significance for the efficient treatment of wastewater with complex components. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing and applying a Prussian blue-based composite thallium removal agent with good adsorption performance for thallium ions, which can achieve rapid solid-liquid separation by utilizing the magnetism of nZVI and has good regeneration performance.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows: A Prussian blue-based nano-zero-valent iron composite material, comprising: The core layer comprises nano-zero valent iron and Prussian blue-based materials; The outer layer comprises a composite layer of Prussian blue-based material analogues, which includes metal ions and ferrocyanide ions, the metal ions including Fe... 2+ Fe 3+ Cu 2+ Ni 2+ Co 2+ and Zn 2+ At least one of them.

[0007] Preferably, the Prussian blue-based material is formed from activated nano-zero-valent iron and ferrocyanide ions.

[0008] Preferably, the number of composite layers is one or more.

[0009] Preferably, the outer layer is a composite layer, the composite layer comprising Fe-based... 2+ Prussian blue-based material analogs and Cu-based 2+ Prussian blue-based material analogues.

[0010] More preferably, based on Cu 2+ Prussian blue-based material analogs in Fe 2+ The outer side of the Prussian blue-based material analogue.

[0011] Preferably, the Prussian blue-based material analogue further contains 2-aminoterephthalic acid and / or imidazole-4-pyruvate. In this invention, the prepared Prussian blue-based nano-zero-valent iron composite material contains a Prussian blue-based material analogue. In this analogue, ferrocyanide ions can form a composite structure with activated nano-zero-valent iron, and 2-aminoterephthalic acid and imidazole-4-pyruvate can form a coordination structure with the activated nano-zero-valent iron. Under the influence of the Prussian blue-based structure and the coordination structure, the adsorption and removal efficiency of thallium ions in the prepared Prussian blue-based nano-zero-valent iron composite material is improved. Furthermore, under acidic conditions, the Prussian blue-based nano-zero-valent iron composite material can be regenerated with a good regeneration adsorption rate.

[0012] This invention discloses a method for preparing the aforementioned Prussian blue-based nano-zero-valent iron composite material, comprising: activating nano-zero-valent iron, then performing composite treatment in a potassium ferrocyanide solution; then treating with a metal salt solution, followed by further composite treatment in a potassium ferrocyanide solution to obtain the Prussian blue-based nano-zero-valent iron composite material. Potassium ferrocyanide provides [Fe(CN)6]. 4- The ligands coordinate with subsequently introduced metal ions to form a Prussian blue-like framework.

[0013] Preferably, activation is performed using a nitric acid solution. Nitric acid activation aims to remove the oxide layer on the nZVI surface and increase the number of surface active sites.

[0014] Preferably, the potassium ferrocyanide solution also contains 2-aminoterephthalic acid and / or imidazole-4-pyruvic acid.

[0015] This invention discloses the use of the above-mentioned Prussian blue-based nano-zero-valent iron composite material in wastewater treatment.

[0016] Preferably, in the preparation of activated nano-zero valent iron, nano-zero valent iron is added to a nitric acid solution, stirred and activated at a temperature of 20-40°C for 5-30 minutes, then the solid is collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron.

[0017] More preferably, in the preparation of activated nano-zero valent iron, the concentration of the nitric acid solution is 0.0001-0.005M, the mass-to-volume ratio of nano-zero valent iron to nitric acid solution is 0.5-2g:50-200mL, and the stirring speed is 100-200rpm.

[0018] Preferably, in the preparation of Prussian blue-based monolayer nano-zero-valent iron products, activated nano-zero-valent iron is dispersed in potassium ferrocyanide solution, and the reaction is stirred at 50-70°C for 1-3 hours. After the reaction is completed, the solid is collected by magnetic separation to obtain Prussian blue-based monolayer nano-zero-valent iron products.

[0019] More preferably, in the preparation of the Prussian blue-based monolayer nano-zero valent iron product, the content of potassium ferrocyanide in the potassium ferrocyanide solution is 0.01-0.1M, the mass-to-volume ratio of activated nano-zero valent iron to potassium ferrocyanide solution is 0.5-2g:100-300mL, and the stirring speed is 100-300rpm.

[0020] More preferably, in the preparation of the Prussian blue-based monolayer nano-zero-valent iron product, the potassium ferrocyanide solution also contains 2-aminoterephthalic acid and imidazole-4-pyruvic acid, wherein the potassium ferrocyanide content in the potassium ferrocyanide solution is 0.05M, the 2-aminoterephthalic acid content in the potassium ferrocyanide solution is 0.6-3wt%, and the imidazole-4-pyruvic acid content in the potassium ferrocyanide solution is 0.4-2wt%.

[0021] More preferably, in the preparation of the Prussian blue-based monolayer nano-zero-valent iron product, the potassium ferrocyanide solution also contains phytic acid, and the content of phytic acid in the potassium ferrocyanide solution is 0.1-1 wt%. In this invention, in addition to using a potassium ferrocyanide solution containing 2-aminoterephthalic acid and imidazole-4-pyruvic acid, phytic acid can also be added. Phytic acid is compounded in the coordination structure of 2-aminoterephthalic acid and imidazole-4-pyruvic acid with activated nano-zero-valent iron. The Prussian blue-based nano-zero-valent iron composite material finally prepared has good adsorption and thallium removal effect, and good regeneration performance, and can be reused multiple times.

[0022] Preferably, in the preparation of the metal-functionalized zero-valent iron nanoparticles, Prussian blue-based monolayer zero-valent iron nanoparticles are dispersed in a metal salt solution, and the reaction is stirred at 40-60°C for 1-3 hours. After the reaction is complete, the solid is collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal cation in the metal salt solution is selected from Fe. 2+ Fe 3+ Cu 2+ Ni 2+ Co 2 + and Zn 2+At least one of the following. By changing the types of metal ions, the composition and properties of the generated Prussian blue analogue can be controlled.

[0023] More preferably, in the preparation of the metal-functionalized nano-zero-valent iron product, the metal salt solution is at least one selected from ferric chloride solution, copper chloride solution, nickel chloride solution, ferrous sulfate solution, and copper nitrate solution. The metal salt solution is a ferric chloride solution, the ferric chloride content in the ferric chloride solution is 0.01-0.1M, and the mass-to-volume ratio of the Prussian blue-based monolayer nano-zero-valent iron product to the ferric chloride solution is 0.5-2g:100-300mL.

[0024] More preferably, in the preparation of the metal-functionalized nano-zero valent iron product, the metal salt solution is a copper chloride solution, the copper chloride content in the copper chloride solution is 0.01-0.1M, and the mass-volume ratio of the Prussian blue monolayer nano-zero valent iron product to the copper chloride solution is 0.5-2g:100-300mL.

[0025] More preferably, in the preparation of metal-functionalized nano-zero valent iron products, the metal salt solution is a nickel chloride solution, the content of ferric chloride in the nickel chloride solution is 0.01-0.1M, and the mass-volume ratio of Prussian blue monolayer nano-zero valent iron products to nickel chloride solution is 0.5-2g:100-300mL.

[0026] More preferably, in the preparation of metal-functionalized nano-zero valent iron products, the metal salt solution is a ferrous sulfate solution, the ferrous sulfate content in the ferrous sulfate solution is 0.01-0.1M, and the mass-volume ratio of Prussian blue monolayer nano-zero valent iron products to ferrous sulfate solution is 0.5-2g:100-300mL.

[0027] More preferably, in the preparation of the metal-functionalized nano-zero valent iron product, the metal salt solution is a copper nitrate solution, the content of copper nitrate in the copper nitrate solution is 0.01-0.1M, and the mass-volume ratio of the Prussian blue monolayer nano-zero valent iron product to the copper nitrate solution is 0.5-2g:100-300mL.

[0028] Preferably, in the preparation of the Prussian blue-based bilayer nano-zero-valent iron product, the metal-functionalized nano-zero-valent iron product is dispersed in a potassium ferrocyanide solution and stirred at 50-70°C for 1-3 hours. After the reaction is completed, the solid is collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain the Prussian blue-based bilayer nano-zero-valent iron product, i.e., the Prussian blue-based nano-zero-valent iron composite material.

[0029] More preferably, in the preparation of the Prussian blue-based bilayer nano-zero ferric iron product, the content of potassium ferrocyanide in the potassium ferrocyanide solution is 0.01-0.1M, the mass-to-volume ratio of the metal-functionalized nano-zero ferric iron product to the potassium ferrocyanide solution is 0.5-2g:100-300mL, and the stirring speed is 100-300rpm.

[0030] This invention provides a Prussian blue-based nano-zero-valent iron composite material and its preparation method. Prussian blue-like coordination polymers are controllably grown on the surface and in the gaps of nano-zero-valent iron through a stepwise reaction to form a tightly bound composite structure that can synergistically leverage the advantages of both components.

[0031] The present invention obtains a Prussian blue-based nano-zero-valent iron composite material by the above method, which has a core-shell or embedded structure, wherein the nano-zero-valent iron serves as the core or supporting framework, and Prussian blue or Prussian blue-like nanocrystals are grown on its surface and in its pores, and the two are tightly bonded together.

[0032] This invention also provides the application of the above-mentioned composite material in the adsorption and removal of thallium ions in wastewater. The nano-zero valent iron in the composite material provides a supporting carrier and electron transport function, while the Prussian blue component efficiently adsorbs specific ions through ion exchange and pore capture, resulting in a synergistic effect. This synergistic mechanism may involve a variety of physical and chemical actions: (1) Nano-zero valent iron provides a highly active surface with a high specific surface area and abundant hydroxyl groups, which can enrich Tl on the surface of the composite material through electrostatic attraction. + (2) Prussian blue component particles provide a large number of adsorption sites to capture Tl. + (3) Fe generated during the corrosion process of nano-zero valent iron 2+ Initiates a Fenton-like reaction, promoting Tl + Oxidized to Tl 3+ And form insoluble Tl(OH)3; (4) The interfacial heterostructure formed between the Prussian blue component and nano-zero valent iron promotes the electron transfer process and induces the structural transformation of the Prussian blue component, thereby benefiting Tl + Adsorption.

[0033] This invention utilizes nitric acid solution to activate nano-zero valent iron, followed by a single-layer composite process using potassium ferrocyanide. In this composite, potassium ferrocyanide and nano-zero valent iron form a Prussian blue-based structure. A metal salt is then added to regulate the formation of a structure containing a Prussian blue analogue with added metal ions. This is followed by another single-layer composite process using potassium ferrocyanide. The metal salt treatment and potassium ferrocyanide treatment constitute a composite process, allowing for the preparation of a Prussian blue-based nano-zero valent iron composite material based on the required number of composite layers. The metal ions can be Fe... 2+ Fe 3+ Cu 2+ Ni 2+ Co2+ and Zn 2+ At least one of the following is present, thus exhibiting the following beneficial effects: Prussian blue-based nano-zero-valent iron composite material has good adsorption performance for thallium ions, can achieve rapid solid-liquid separation using the magnetism of nZVI, and has good regeneration performance. Therefore, this invention provides a method for preparing and applying a Prussian blue-based composite thallium removal agent with good adsorption performance for thallium ions, can achieve rapid solid-liquid separation using the magnetism of nZVI, and has good regeneration performance. Attached Figure Description

[0034] Figure 1 This is a graph showing the thallium ion removal rate.

[0035] Figure 2 This is a graph showing the regeneration adsorption rate. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The concepts involved in this application will first be described with reference to the accompanying drawings. It should be noted that the following descriptions of various concepts are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] The Prussian blue-based nano-zero-valent iron composite material in this invention can be a Prussian blue-based monolayer nano-zero-valent iron product, a metal-functionalized nano-zero-valent iron product, a Prussian blue-based bilayer nano-zero-valent iron product, a metal-functionalized bilayer nano-zero-valent iron product, etc. In the conception of this invention, the Prussian blue-based nano-zero-valent iron composite material is a structure with activated nano-zero-valent iron as the core, combined with different treatment layers on the outside. These treatment layers can be repeated multiple times, and the treatment layers can be the same or different.

[0039] Example 1: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0040] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0041] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a ferric chloride solution with a ferric chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to ferric chloride solution was 1 g: 200 mL.

[0042] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain the Prussian blue-based bilayer nano-zero-valent iron products, i.e., Prussian blue-based nano-zero-valent iron composite materials. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0043] Example 2: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0044] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0045] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0046] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain the Prussian blue-based bilayer nano-zero-valent iron products, i.e., Prussian blue-based nano-zero-valent iron composite materials. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0047] Example 3: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0048] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0049] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a nickel chloride solution with a ferric chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to nickel chloride solution was 1 g: 200 mL.

[0050] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain the Prussian blue-based bilayer nano-zero-valent iron products, i.e., Prussian blue-based nano-zero-valent iron composite materials. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0051] Example 4: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0052] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0053] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a ferrous sulfate solution with a ferrous sulfate content of 0.04 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to ferrous sulfate solution was 1 g: 200 mL.

[0054] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0055] Preparation of metal-functionalized bilayer nano-zero-valent iron products: Prussian blue-based bilayer nano-zero-valent iron products were dispersed in a metal salt solution and stirred at 60°C for 1.5 h. After the reaction was completed, the solid was collected by magnetic separation to obtain the metal-functionalized bilayer nano-zero-valent iron products, namely, Prussian blue-based nano-zero-valent iron composite materials. The metal salt solution was a copper nitrate solution with a copper nitrate content of 0.04 M. The mass-to-volume ratio of Prussian blue-based monolayer nano-zero-valent iron products to copper nitrate solution was 1 g: 200 mL.

[0056] Example 5: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0057] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.1 M, and the mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0058] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a ferric chloride solution with a ferric chloride content of 0.1 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to ferric chloride solution was 1 g: 200 mL.

[0059] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain the Prussian blue-based bilayer nano-zero-valent iron products, i.e., Prussian blue-based nano-zero-valent iron composite materials. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.1M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0060] Comparative Example 1: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.0001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0061] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0062] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a ferric chloride solution with a ferric chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to ferric chloride solution was 1 g: 200 mL.

[0063] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain the Prussian blue-based bilayer nano-zero-valent iron products, i.e., Prussian blue-based nano-zero-valent iron composite materials. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0064] Comparative Example 2: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0065] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0066] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a ferric chloride solution with a ferric chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to ferric chloride solution was 1 g: 200 mL.

[0067] Example 6: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0068] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0069] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a ferric chloride solution with a ferric chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to ferric chloride solution was 1 g: 200 mL.

[0070] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation to obtain Prussian blue-based monolayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0071] Preparation of metal-functionalized bilayer nano-zero-valent iron products: Prussian blue-based bilayer nano-zero-valent iron products were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was completed, the solid was collected by magnetic separation to obtain the metal-functionalized bilayer nano-zero-valent iron products. The metal salt solution was a ferric chloride solution with a ferric chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based bilayer nano-zero-valent iron products to ferric chloride solution was 1 g: 200 mL.

[0072] Preparation of Prussian blue-based trilayer nano-zero-valent iron products: Metal-functionalized bilayer nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain the Prussian blue-based trilayer nano-zero-valent iron products, i.e., Prussian blue-based nano-zero-valent iron composite materials. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05M, the mass-to-volume ratio of the metal-functionalized bilayer nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL, and the stirring speed was 200 rpm.

[0073] Example 7: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0074] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide solution also contained 2-aminoterephthalic acid and imidazole-4-pyruvic acid. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, the 2-aminoterephthalic acid content was 2.7 wt%, and the imidazole-4-pyruvic acid content was 1.8 wt%. The mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0075] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0076] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0077] Example 8: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0078] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide solution also contained 2-aminoterephthalic acid and imidazole-4-pyruvic acid. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, the 2-aminoterephthalic acid content was 2.7 wt%, and the imidazole-4-pyruvic acid content was 0.6 wt%. The mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0079] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0080] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0081] Example 9: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0082] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide solution also contained 2-aminoterephthalic acid and imidazole-4-pyruvic acid. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, the 2-aminoterephthalic acid content was 0.8 wt%, and the imidazole-4-pyruvic acid content was 1.8 wt%. The mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0083] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0084] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0085] Example 10: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0086] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide solution also contained 2-aminoterephthalic acid and imidazole-4-pyruvic acid. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, the 2-aminoterephthalic acid content was 0.9 wt%, and the imidazole-4-pyruvic acid content was 0.6 wt%. The mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0087] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0088] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0089] Example 11: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0090] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide solution also contained 2-aminoterephthalic acid, phytic acid, and imidazole-4-pyruvic acid. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, the 2-aminoterephthalic acid content was 2.7 wt%, the phytic acid content was 0.9 wt%, and the imidazole-4-pyruvic acid content was 1.8 wt%. The mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0091] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0092] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0093] Example 12: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0094] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide solution also contained 2-aminoterephthalic acid, phytic acid, and imidazole-4-pyruvic acid. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, the 2-aminoterephthalic acid content was 2.7 wt%, the phytic acid content was 0.2 wt%, and the imidazole-4-pyruvic acid content was 1.8 wt%. The mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0095] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0096] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0097] Comparative Example 3: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0098] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide solution also contained 2-aminoterephthalic acid and imidazole-4-pyruvic acid. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, the 2-aminoterephthalic acid content was 2.7 wt%, and the imidazole-4-pyruvic acid content was 0.1 wt%. The mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0099] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0100] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0101] Comparative Example 4: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0102] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide solution also contained 2-aminoterephthalic acid and imidazole-4-pyruvic acid. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, the 2-aminoterephthalic acid content was 0.1 wt%, and the imidazole-4-pyruvic acid content was 1.8 wt%. The mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0103] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0104] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0105] Comparative Example 5: A method for preparing a Prussian blue-based nano-zero-valent iron composite material Preparation of activated nano-zero valent iron: Nano-zero valent iron was added to a nitric acid solution and stirred at 25°C for 10 min to activate it. The solid was then collected by magnetic separation and washed with oxygen-free deionized water to obtain activated nano-zero valent iron. The concentration of the nitric acid solution was 0.001 M, and the mass-to-volume ratio of nano-zero valent iron to nitric acid solution was 1 g:100 mL; the stirring speed was 150 rpm.

[0106] Preparation of Prussian blue-based monolayer nano-zero-valent iron: Activated nano-zero-valent iron was dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was complete, the solid was collected by magnetic separation to obtain the Prussian blue-based monolayer nano-zero-valent iron product. The potassium ferrocyanide solution also contained 2-aminoterephthalic acid and imidazole-4-pyruvic acid. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, the 2-aminoterephthalic acid content was 0.1 wt%, and the imidazole-4-pyruvic acid content was 0.1 wt%. The mass-to-volume ratio of activated nano-zero-valent iron to potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0107] Preparation of metal-functionalized zero-valent iron nanoparticles: Prussian blue-based monolayer zero-valent iron nanoparticles were dispersed in a metal salt solution and stirred at 50°C for 1.5 h. After the reaction was complete, the solid was collected by magnetic separation to obtain the metal-functionalized zero-valent iron nanoparticles. The metal salt solution was a copper chloride solution with a copper chloride content of 0.05 M. The mass-to-volume ratio of Prussian blue-based monolayer zero-valent iron nanoparticles to copper chloride solution was 1 g: 200 mL.

[0108] Preparation of Prussian blue-based bilayer nano-zero-valent iron products: Metal-functionalized nano-zero-valent iron products were dispersed in a potassium ferrocyanide solution and stirred at 60°C for 2 hours. After the reaction was completed, the solid was collected by magnetic separation, washed with oxygen-free deionized water and anhydrous ethanol, and freeze-dried to obtain Prussian blue-based bilayer nano-zero-valent iron products. The potassium ferrocyanide content in the potassium ferrocyanide solution was 0.05 M, and the mass-to-volume ratio of the metal-functionalized nano-zero-valent iron products to the potassium ferrocyanide solution was 1 g: 200 mL; the stirring speed was 200 rpm.

[0109] Experimental example: 1. Adsorption performance test Thallium-containing wastewater with a thallium ion concentration of 50 μg / L was prepared, and the pH was adjusted to 7.0 with dilute hydrochloric acid or sodium hydroxide. 100 mL of the wastewater was taken, and 50 mg of Prussian blue-based nano-zero-valent iron composite material was added. The mixture was then shaken in a constant-temperature shaker at 25°C and 150 rpm for 180 minutes. The thallium ion concentration in the solution was measured, and the thallium ion removal rate was calculated. The Prussian blue-based nano-zero-valent iron composite material was prepared according to the examples and comparative examples.

[0110] The thallium ion removal rate in the adsorption and removal of thallium ions from thallium-containing wastewater using Prussian blue-based nano-zero-valent iron composite materials is shown in the following figures. Figure 1As shown, S1 is Example 1, S2 is Example 2, S3 is Example 3, S4 is Example 4, S5 is Example 5, D1 is Comparative Example 1, D2 is Comparative Example 2, S6 is Example 6, S7 is Example 7, S8 is Example 8, S9 is Example 9, S10 is Example 10, S11 is Example 11, S12 is Example 12, D3 is Comparative Example 3, D4 is Comparative Example 4, and D5 is Comparative Example 5. In this invention, nano-zero-valent iron is first activated with nitric acid solution, and then potassium ferrocyanide is used for a single-layer composite. In this composite, potassium ferrocyanide and nano-zero-valent iron can form a Prussian blue-based structure. Then, a metal salt is added to regulate the formation of a Prussian blue analog containing added metal ions. Another layer of potassium ferrocyanide is then used for composite. The treatment with metal salt and potassium ferrocyanide constitutes a composite layer. Prussian blue-based nano-zero-valent iron composite materials are prepared according to the required number of composite layers. The metal ions can be Fe... 2+ Fe 3+ Cu 2+ Ni 2+ Co 2+ and Zn 2+At least one of the following is true: in this invention, composites with two or more layers are superior to composites with one layer, and composites with three layers are superior to composites with two layers. In this invention, a two-layer composite is used as a representative for testing. In the preparation of Prussian blue-based nano-zero-valent iron composite materials, the concentration of nitric acid cannot be too low; otherwise, the nano-zero-valent iron cannot be effectively activated. Prussian blue-based nano-zero-valent iron composite materials prepared under conditions where nano-zero-valent iron cannot be effectively activated have poor removal effects on thallium ions. In the preparation of Prussian blue-based nano-zero-valent iron composite materials, if the final treatment is a metal salt treatment, i.e., after metal salt treatment, potassium ferrocyanide treatment is not used, the final Prussian blue-based nano-zero-valent iron composite material will have poor removal effects on thallium ions. In this invention, in the preparation of Prussian blue-based nano-zero-valent iron composite materials, in the first composite stage, potassium ferrocyanide solution can be added to form coordination with iron ions. The reagents used in this invention include 2-aminoterephthalic acid and imidazole-4-pyruvic acid. Within a specific range of dosage, 2-aminoterephthalic acid and imidazole-4-pyruvic acid can improve the removal efficiency of thallium ions in the final Prussian blue-based nano-zero-valent iron composite material. If either 2-aminoterephthalic acid or imidazole-4-pyruvic acid is used within a specific range, and the other is used in too low a concentration, the removal efficiency of thallium ions in the Prussian blue-based nano-zero-valent iron composite material will not be effectively improved. Similarly, if both 2-aminoterephthalic acid and imidazole-4-pyruvic acid are used in too low a concentration, the removal efficiency of thallium ions in the Prussian blue-based nano-zero-valent iron composite material will also not be improved. In addition to 2-aminoterephthalic acid and imidazole-4-pyruvic acid, phytic acid can also be added in this invention. The use of phytic acid can further improve the removal efficiency of thallium ions in the Prussian blue-based nano-zero-valent iron composite material.

[0111] 2. Regeneration performance test The Prussian blue-based nano-zero-valent iron composite material, after adsorbing thallium ions, was regenerated using 0.05M hydrochloric acid. This regeneration process was repeated five times, and the regeneration adsorption rate of the Prussian blue-based nano-zero-valent iron composite material was calculated. The Prussian blue-based nano-zero-valent iron composite material was prepared according to the examples and comparative examples.

[0112] After regeneration, the Prussian blue-based nano-zero-valent iron composite material exhibits a regeneration adsorption rate of thallium ions in thallium-containing wastewater as follows: Figure 2As shown, S1 is Example 1, S2 is Example 2, S3 is Example 3, S4 is Example 4, S5 is Example 5, D1 is Comparative Example 1, D2 is Comparative Example 2, S6 is Example 6, S7 is Example 7, S8 is Example 8, S9 is Example 9, S10 is Example 10, S11 is Example 11, S12 is Example 12, D3 is Comparative Example 3, D4 is Comparative Example 4, and D5 is Comparative Example 5. In this invention, nano-zero-valent iron is first activated with nitric acid solution, and then potassium ferrocyanide is used for a single-layer composite. In this composite, potassium ferrocyanide and nano-zero-valent iron can form a Prussian blue-based structure. Then, a metal salt is added to regulate the formation of a Prussian blue analog containing added metal ions. Another layer of potassium ferrocyanide is then used for composite. The treatment with metal salt and potassium ferrocyanide constitutes a composite layer. Prussian blue-based nano-zero-valent iron composite materials are prepared according to the required number of composite layers. The metal ions can be Fe... 2+ Fe 3+ Cu 2+ Ni 2+ Co 2+ and Zn 2+At least one of the following is true: in this invention, composites with two or more layers are superior to composites with one layer, and composites with three layers are superior to composites with two layers. In this invention, a two-layer composite is used as a representative for testing. In the preparation of Prussian blue-based nano-zero-valent iron composite materials, the concentration of nitric acid cannot be too low; otherwise, the nano-zero-valent iron cannot be effectively activated. Prussian blue-based nano-zero-valent iron composite materials prepared under conditions where nano-zero-valent iron cannot be effectively activated have poor adsorption and regeneration effects on thallium ions. In the preparation of Prussian blue-based nano-zero-valent iron composite materials, if the final treatment is a metal salt treatment, i.e., after metal salt treatment, potassium ferrocyanide treatment is not used, the final Prussian blue-based nano-zero-valent iron composite material will have poor adsorption and regeneration effects on thallium ions. In this invention, in the preparation of Prussian blue-based nano-zero-valent iron composite materials, in the first composite stage, potassium ferrocyanide solution can be added to form a coordination structure with iron ions. The reagents include 2-aminoterephthalic acid and imidazole-4-pyruvate. Within a specific range of dosage, 2-aminoterephthalic acid and imidazole-4-pyruvate can improve the adsorption and regeneration effect of thallium ions on the final Prussian blue-based nano-zero-valent iron composite material. If either 2-aminoterephthalic acid or imidazole-4-pyruvate is used in a low amount, the adsorption and regeneration effect of thallium ions on the Prussian blue-based nano-zero-valent iron composite material will not be effectively improved. Similarly, if both 2-aminoterephthalic acid and imidazole-4-pyruvate are used in too low a amount, the adsorption and regeneration effect of thallium ions on the Prussian blue-based nano-zero-valent iron composite material will also not be improved. In addition to 2-aminoterephthalic acid and imidazole-4-pyruvate, phytic acid can also be added in this invention. The use of phytic acid can further improve the adsorption and regeneration effect of thallium ions on the Prussian blue-based nano-zero-valent iron composite material.

[0113] The Prussian blue-based nano-zero-valent iron composite materials prepared by this invention can all achieve solid-liquid separation within 2 minutes using an external magnet, demonstrating good operational convenience.

[0114] The embodiments and / or implementation methods described above are merely preferred embodiments and / or implementation methods for implementing the technology of the present invention, and are not intended to limit the implementation methods of the technology of the present invention in any way. Any person skilled in the art can make some modifications or alterations to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present invention, but they should still be regarded as the technology or embodiments that are substantially the same as the present invention.

[0115] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A Prussian blue-based nano-zero-valent iron composite material, comprising: The core layer comprises nano-zero valent iron and Prussian blue-based materials; an outer layer comprising a composite layer of Prussian blue-based material analogs comprising at least one of Fe 2+ , Fe 3+ , Cu 2+ , Ni 2+ , Co 2+ , and Zn 2+ and ferrocyanide ions.

2. The Prussian blue-based nanoscale zero-valent iron composite material of claim 1, wherein, The Prussian blue-based material is formed from activated nano-zero-valent iron and ferrocyanide ions.

3. The Prussian blue-based nanoscale zero-valent iron composite of claim 1, wherein the Prussian blue-based nanoscale zero-valent iron composite is characterized by: The number of composite layers is one or more.

4. The Prussian blue-based nanoscale zero-valent iron composite of claim 1, wherein, The outer layer is 2 composite layers, the composite layer includes Fe 2+ based Prussian blue-based material analogues and Cu 2+ based Prussian blue-based material analogues.

5. The Prussian blue-based nano-zero-valent iron composite material according to claim 4, characterized in that, The Cu-based 2+ Prussian blue analogs are similar to Fe-based 2+ Prussian blue analogs on the outside.

6. The Prussian blue-based nano-zero-valent iron composite material according to claim 1, characterized in that, The Prussian blue-based material analogue also contains 2-aminoterephthalic acid and / or imidazole-4-pyruvic acid.

7. The method for preparing the Prussian blue-based nano-zero-valent iron composite material according to claim 1, comprising: Nano-sized zero-valent iron was activated and then compounded in a potassium ferrocyanide solution; Then, it is added to a metal salt solution for treatment, and then composited in a potassium ferrocyanide solution to prepare a Prussian blue-based nano-zero-valent iron composite material.

8. The preparation method according to claim 7, characterized in that, The activation is performed using nitric acid solution.

9. The preparation method according to claim 7, characterized in that, The potassium ferrocyanide solution also contains 2-aminoterephthalic acid and / or imidazole-4-pyruvic acid.

10. The use of the Prussian blue-based nano-zero-valent iron composite material according to claim 1 in wastewater treatment.

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