Preparation method and application of a nickel-iron bimetallic persulfate soil remediation material

Abstract

The application discloses a preparation method of a nickel-iron bimetallic persulfate soil remediation material and application thereof. The remediation material takes submicron rhombic composite particles of nickel oxide and ferroferric oxide as an active component, sodium persulfate or potassium persulfate as an oxidant, a mixture of starch and fructose as a binder, hydroxypropyl methyl cellulose as a coating agent, and tetrahydrofurfuryl alcohol as a morphology control agent of the active component. The mass percentage of the active component is 20-30% based on the mass of the oxidant, the mass percentage of the binder is 5-10%, and the mass percentage of the coating agent is 10-20%. The submicron rhombic composite particles of nickel oxide and ferroferric oxide are prepared by a hydrothermal method as the active component, and then iron-cobalt bimetallic oxide nanofibers are prepared as the active component. The active component is mixed with the oxidant by using the binder to prepare particles, and finally the nickel-iron bimetallic persulfate soil remediation material is formed by using the coating agent for coating. The remediation material has the advantages of simple process, low price, high durability, efficient removal of heavy organic pollutants in soil, high economic value and wide market application prospect.

Description

Technical Field

[0001] This invention relates to a method for preparing a nickel-iron bimetallic persulfate soil remediation material and its application, belonging to the field of soil remediation. Background Technology

[0002] Commonly used remediation technologies for organic pollution both domestically and internationally include chemical oxidation / reduction, cement kiln co-processing, leaching, vapor extraction, and bioremediation. Chemical oxidation technology involves adding chemical oxidants to contaminated sites, causing the pollutants in the soil to oxidize and ultimately render the pollutants harmless. It is widely used due to its thorough degradation of organic pollutants and short remediation cycle. Chemical oxidation technology for treating organic contaminated sites is relatively mature, and a complete process system has been established both domestically and internationally. Patent CN110961451B discloses a soil remediation material and method for oxidatively degrading organic pollutants, using peroxide as the oxidant. By adding stabilizers and activators, peroxidation is avoided, effectively removing organic pollutants from the soil. Patent CN116355621A discloses a remediation material and method for organically contaminated soil coupled with zero-valent iron and chlorine dioxide. This method not only effectively removes organic pollutants but also provides trace iron to the soil, increasing soil fertility.

[0003] The above solutions have shown good results in specific fields, but their application areas are limited. Furthermore, the oxidant persulfate has strong oxidizing properties and will decompose and degrade in performance after being left in the air for too long, which cannot meet the requirements for long-term transportation of the agent. Therefore, it is essential to develop a soil remediation agent that can be stored stably and has high efficiency in oxidizing organic pollutants. Summary of the Invention

[0004] The purpose of this invention is to solve the problem of stable storage and efficient oxidation of soil remediation materials during the remediation of organically polluted soil. Another purpose of this invention is to provide a method for preparing nickel-iron bimetallic persulfate soil remediation materials.

[0005] This invention can be achieved through the following technical solution: The remediation material uses submicron rhombic composite particles of nickel oxide and iron oxide as the active component, persulfate as the oxidant, a mixture of starch and fructose as the binder, hydroxypropyl methylcellulose as the coating agent, and tetrahydrofurfuryl alcohol as the morphology control agent for the active component. In the catalyst design, nickel oxide and iron oxide not only have excellent redox properties, but nickel oxide also has excellent C / C bond breaking properties. Furthermore, using tetrahydrofurfuryl alcohol as a morphology control agent to grow the active component into a submicron rhombic structure not only increases the contact between the catalyst surface and the reactants, thereby promoting the activation of organic pollutant molecules and ultimately improving the remediation effect of organic polluted soil; in addition, iron oxide is magnetic, allowing for the recovery and reuse of the active component after soil remediation by leaching and magnetic separation as needed; persulfate has excellent oxidation properties and can deeply oxidize organic pollutant molecules under the catalytic promotion of nickel oxide and iron oxide; persulfate... Due to their excellent oxidizing properties, persulfates gradually decompose during their existence, leading to a decline in performance during use. The mixed binder of starch and fructose can fully mix the active components with persulfates and use hydroxypropyl methylcellulose to coat the active components and oxidants, thereby preventing the oxidants from coming into contact with air. The role of starch and fructose is to ensure that the active components and oxidants can be mixed in the expected proportion and can be prepared into spheres for hydroxypropyl methylcellulose coating. At the same time, hydroxypropyl cellulose, starch and fructose not only dissolve in water during use, thus not affecting the use of soil remediation materials, but also can gradually oxidize in natural soil to form organic fertilizer, enhancing soil fertility.

[0006] This invention can be achieved through the following technical solution: The repair material uses submicron rhombic composite particles of nickel oxide and iron oxide as the active component, persulfate as the oxidant, a mixture of starch and fructose as the binder, hydroxypropyl methylcellulose as the coating agent, and tetrahydrofurfuryl alcohol as the morphology control agent for the active component; based on the mass of the oxidant, the mass percentage of the active component is 20-30%, the mass percentage of the binder is 5-10%, and the mass percentage of the coating agent is 10-20%. The preparation method of this material includes the following steps:

[0007] (1) Preparation of nickel-iron submicron rhombic composite particles

[0008] Nickel salt, iron salt, active component morphology control agent, and deionized water are mixed evenly and then placed in a hydrothermal reactor for hydrothermal reaction. After the reaction is completed, the mixture is filtered and dried, and then calcined at high temperature to obtain nickel-iron submicron rhombic composite particles.

[0009] (2) Preparation of spherical particles

[0010] Starch, fructose and deionized water were mixed to prepare an adhesive slurry. Then, persulfate was weighed and stirred evenly with the nickel-iron submicron rhombic composite particles obtained in step (1) and placed in the adhesive slurry for stirring. After stirring evenly, the mixture was placed in an oven to dry. After drying, the mixture was made into spherical particles and sieved to obtain mixed spherical particles of persulfate and nickel-iron submicron rhombic composite particles.

[0011] (3) Preparation of soil remediation materials

[0012] Hydroxypropyl methylcellulose is dissolved in deionized water and stirred to form a hydroxypropyl methylcellulose solution. Then, the mixed spherical particles obtained in step (2) are placed in the hydroxypropyl methylcellulose solution for 5-10 seconds and then removed and dried. The mixture is repeatedly placed in the hydroxypropyl methylcellulose solution and dried until the hydroxypropyl methylcellulose solution is used up, thereby obtaining the soil remediation material.

[0013] In the technical solution of this invention, the mass ratio of nickel oxide to iron oxide is 1:(0.5~1).

[0014] In the technical solution of this invention: the nickel salt in step (1) is nickel nitrate hexahydrate or nickel chloride hexahydrate, the iron salt is ferric nitrate nonahydrate or ferric chloride hexahydrate, and the morphology control agent of the active component is tetrahydrofurfuryl alcohol.

[0015] In the technical solution of the present invention: the mass ratio of nickel salt, active component morphology control agent and deionized water in step (1) is 1:(0.05~0.1):(40~60).

[0016] In the technical solution of the present invention: the temperature of the hydrothermal reaction in step (1) is 160-180℃, the time of the hydrothermal reaction is 6-12h, the drying temperature is 80-100℃, the drying time is 4-6h, the high-temperature calcination temperature is 500-700℃, and the high-temperature calcination time is 2-4h.

[0017] In the technical solution of this invention: the mass ratio of starch, fructose and deionized water in step (2) is 1:(0.1~0.3):(1~2).

[0018] In the technical solution of this invention: the persulfate mentioned in step (2) is sodium persulfate or potassium persulfate.

[0019] In the technical solution of the present invention: the drying temperature in step (2) is 20-30℃, the drying time is 12-24h, and the metal mesh screen used for sieving is 5 mesh and 7 mesh.

[0020] In the technical solution of this invention: the mass ratio of hydroxypropyl methylcellulose and deionized water in step (3) is (3-5):100, the drying temperature is 20-40℃, and the drying time is 4-6h.

[0021] In the technical solution of this invention, the nickel-iron bimetallic persulfate soil remediation material prepared by the method is applied to the remediation of soil organic pollutants.

[0022] Furthermore, the organic compound is chlorobenzene or polychlorinated biphenyl.

[0023] Beneficial effects:

[0024] (1) The remediation material uses submicron rhombic composite particles of nickel oxide and iron oxide as active components, which can promote the decomposition of organic pollutants.

[0025] (2) The mixture of starch and fructose can mix the active components with the oxidant in proportion, which is beneficial for the direct use of soil remediation materials during use, without the need for on-site mixing.

[0026] (3) Starch, fructose and hydroxypropyl methylcellulose can prevent the soil remediation materials from gradually oxidizing after preparation, thus affecting the effect. In addition, the adhesives and coatings can be oxidized in the natural environment after entering the soil, increasing soil fertility.

[0027] (4) The raw materials for this remediation material are readily available, the process is simple, the pollutant removal efficiency is high, and the removal range is wide. It has high economic value and broad market application prospects. Attached Figure Description

[0028] Appendix Figure 1 FE-SEM image of the active component prepared in Example 1;

[0029] Appendix Figure 2 FE-SEM image of the active component prepared in Comparative Example 1. Detailed Implementation

[0030] The following examples further illustrate the preparation method of the nickel-iron bimetallic persulfate soil remediation material of the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0031] Unless otherwise specified, the experimental methods in the following embodiments are conventional methods in the art, and the experimental apparatus and experimental materials are commercially available unless otherwise specified.

[0032] Performance evaluation: Weigh 10g of soil remediation material and mix thoroughly with 100g of contaminated clay soil (polychlorinated biphenyl or chlorobenzene content in the soil: 2%). Then weigh 200g of deionized water and add it to the soil. After standing for 2 hours, filter to obtain soil residue and filtered water. Use liquid chromatography to determine the content of organic pollutants in the filtered water and calculate the removal rate of organic pollutants.

[0033] Example 1

[0034] (1) Preparation of nickel-iron submicron rhombic composite particles

[0035] 3.89 g of nickel nitrate hexahydrate, 5.23 g of ferric nitrate nonahydrate, 0.19 g of tetrahydrofurfuryl alcohol, and 155.60 g of deionized water were mixed evenly and then placed in a hydrothermal reactor and reacted at 160 °C for 12 h. After the reaction, the mixture was filtered, dried at 80 °C for 6 h, and then calcined at 500 °C for 4 h to obtain nickel-iron submicron rhombic composite particles. Figure 1 );

[0036] (2) Preparation of spherical particles

[0037] Weigh 0.91g starch, 0.09g fructose and 0.91g deionized water and mix them to prepare an adhesive slurry. Then weigh 10g sodium persulfate and stir it evenly with the nickel-iron submicron rhombic composite particles obtained in step (1). Place it in the adhesive slurry and stir. After stirring evenly, place it in an oven at 20℃ and dry for 24h. After drying, make the mixture into spherical particles and sieve them through a 5-mesh sieve and a 7-mesh sieve to obtain mixed spherical particles of persulfate and nickel-iron submicron rhombic composite particles with a size of 2.8-4.0mm.

[0038] (3) Preparation of soil remediation materials

[0039] Dissolve 1g of hydroxypropyl methylcellulose in 20g of deionized water and stir to form a hydroxypropyl methylcellulose solution. Then, place the mixed spherical particles obtained in step (2) into the hydroxypropyl methylcellulose solution for 5-10 seconds and then take them out. Place them in an oven at 20°C for 6 hours and dry them repeatedly in the hydroxypropyl methylcellulose solution until the hydroxypropyl methylcellulose solution is used up, thereby obtaining the soil remediation material.

[0040] (4) Performance Evaluation

[0041] 10g of soil remediation material was weighed and mixed thoroughly with 100g of contaminated clay soil (chlorobenzene content in the soil: 2%). Then, 200g of deionized water was weighed and added to the soil. After standing for 2 hours, the mixture was filtered to obtain soil residue and filtered water. The content of organic pollutants in the filtered water was determined by liquid chromatography, and the removal rate of organic pollutants was calculated. The removal rate of organic pollutants for this sample was 99.4%.

[0042] Example 2

[0043] (1) Preparation of nickel-iron submicron rhombic composite particles

[0044] 6.36g nickel chloride hexahydrate, 3.50g ferric chloride hexahydrate, 0.64g tetrahydrofurfuryl alcohol, and 381.6g deionized water were mixed evenly and then placed in a hydrothermal reactor and hydrothermally reacted at 180℃ for 6 hours. After the reaction was completed, the mixture was filtered, dried at 100℃ for 4 hours, and then calcined at 700℃ for 2 hours to obtain nickel-iron submicron rhombic composite particles.

[0045] (2) Preparation of spherical particles

[0046] Weigh 0.36g starch, 0.14g fructose and 0.72g deionized water and mix them to prepare an adhesive slurry. Then weigh 10g sodium persulfate and stir it evenly with the nickel-iron submicron rhombic composite particles obtained in step (1). Place it in the adhesive slurry and stir. After stirring evenly, place it in an oven at 30℃ and dry for 124h. After drying, make the mixture into spherical particles and sieve them through a 5-mesh sieve and a 7-mesh sieve to obtain mixed spherical particles of persulfate and nickel-iron submicron rhombic composite particles with a size of 2.8-4.0mm.

[0047] (3) Preparation of soil remediation materials

[0048] 2g of hydroxypropyl methylcellulose was dissolved in 66.67g of deionized water and stirred to form a hydroxypropyl methylcellulose solution. Then, the mixed spherical particles obtained in step (2) were placed in the hydroxypropyl methylcellulose solution for 5-10 seconds and then removed. They were then placed in an oven at 40°C for 4 hours and dried. The mixture was repeatedly placed in the hydroxypropyl methylcellulose solution and dried until the hydroxypropyl methylcellulose solution was used up, thereby obtaining the soil remediation material.

[0049] (4) Performance Evaluation

[0050] 10g of soil remediation material was weighed and mixed thoroughly with 100g of contaminated clay soil (polychlorinated biphenyl content in the soil: 2%). Then, 200g of deionized water was weighed and added to the soil. After standing for 2 hours, the mixture was filtered to obtain soil residue and filtered water. The content of organic pollutants in the filtered water was determined by liquid chromatography, and the removal rate of organic pollutants was calculated. The removal rate of organic pollutants for this sample was 96.4%.

[0051] Comparative Example 1

[0052] (1) Preparation of soil remediation materials

[0053] Except that tetrahydrofurfuryl alcohol was not used as a morphology control agent in the preparation of the soil remediation material, the other conditions were the same as in Example 1;

[0054] (2) Performance Evaluation

[0055] 10g of soil remediation material was weighed and mixed thoroughly with 100g of contaminated clay soil (chlorobenzene content in the soil: 2%). Then, 200g of deionized water was weighed and added to the soil. After standing for 2 hours, the mixture was filtered to obtain soil residue and filtered water. The content of organic pollutants in the filtered water was determined by liquid chromatography, and the removal rate of organic pollutants was calculated. The removal rate of organic pollutants for this sample was 48.3%.

[0056] (3) Comparison effect

[0057] Compared to Example 1, the soil remediation material does not use tetrahydrofurfuryl alcohol as a morphology control agent during preparation, and the active components will form a micron-sized blocky structure. Figure 2 Although the surface is porous, the contact area with the reaction molecules is reduced compared to the submicron rhombic structure, resulting in a significant decrease in the efficiency of organic matter removal.

[0058] Comparative Example 2

[0059] (1) Preparation of soil remediation materials

[0060] Except that starch and fructose are not used as binders in the preparation of soil remediation materials, the other conditions are the same as in Example 2; (2) Comparative effects

[0061] Compared to Example 2, the soil remediation material does not use starch and fructose as binders. Hydroxypropyl methylcellulose is difficult to encapsulate the mixture of active components and oxidants into spherical particles, mainly because the oxidant persulfate dissolves rapidly in the hydroxypropyl methylcellulose solution.

[0062] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Based on the technical solutions of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A method for preparing a nickel-iron bimetallic persulfate soil remediation material, characterized in that: This repair material uses submicron rhombic composite particles of nickel oxide and iron oxide as the active component, persulfate as the oxidant, a mixture of starch and fructose as the binder, hydroxypropyl methylcellulose as the coating agent, and tetrahydrofurfuryl alcohol as the morphology control agent for the active component. Based on the mass of the oxidant, the mass percentage of the active component is 20-30%, the mass percentage of the binder is 5-10%, and the mass percentage of the coating agent is 10-20%. The preparation method of this material includes the following steps: (1) Preparation of nickel-iron submicron rhombic composite particles Nickel salt, iron salt, active component morphology control agent, and deionized water are mixed evenly and then placed in a hydrothermal reactor for hydrothermal reaction. After the reaction is completed, the mixture is filtered and dried, and then calcined at high temperature to obtain nickel-iron submicron rhombic composite particles. (2) Preparation of spherical particles Starch, fructose and deionized water were mixed to prepare an adhesive slurry. Then, persulfate was weighed and stirred evenly with the nickel-iron submicron rhombic composite particles obtained in step (1) and placed in the adhesive slurry for stirring. After stirring evenly, the mixture was placed in an oven to dry. After drying, the mixture was made into spherical particles and sieved to obtain mixed spherical particles of persulfate and nickel-iron submicron rhombic composite particles. (3) Preparation of soil remediation materials Hydroxypropyl methylcellulose is dissolved in deionized water and stirred to form a hydroxypropyl methylcellulose solution. Then, the mixed spherical particles obtained in step (2) are placed in the hydroxypropyl methylcellulose solution for 5-10 seconds and then removed and dried. The mixture is repeatedly placed in the hydroxypropyl methylcellulose solution and dried until the hydroxypropyl methylcellulose solution is used up, thereby obtaining the soil remediation material.

2. The preparation method according to claim 1, characterized in that: The mass ratio of nickel oxide to iron oxide is 1:(0.5~1).

3. The preparation method according to claim 1, characterized in that: The nickel salt in step (1) is nickel nitrate hexahydrate or nickel chloride hexahydrate, the iron salt is ferric nitrate nonahydrate or ferric chloride hexahydrate, and the morphology control agent of the active component is tetrahydrofurfuryl alcohol.

4. The preparation method according to claim 1, characterized in that: The mass ratio of nickel salt, active component morphology control agent and deionized water in step (1) is 1:(0.05-0.1):(40-60).

5. The preparation method according to claim 1, characterized in that: The hydrothermal reaction in step (1) is carried out at a temperature of 160-180°C for 6-12 hours, the drying temperature is 80-100°C for 4-6 hours, the high-temperature calcination temperature is 500-700°C for 2-4 hours.

6. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of starch, fructose and deionized water is 1:(0.1-0.3):(1-2).

7. The preparation method according to claim 1, characterized in that: The persulfate mentioned in step (2) is sodium persulfate or potassium persulfate.

8. The preparation method according to claim 1, characterized in that: The drying temperature in step (2) is 20-30°C, the drying time is 12-24 hours, and the metal mesh sieve used for sieving is 5 mesh and 7 mesh.

9. The preparation method according to claim 1, characterized in that: The mass ratio of hydroxypropyl methylcellulose to deionized water in step (3) is (3-5):100, the drying temperature is 20-40℃, and the drying time is 4-6h.

10. The application of the nickel-iron bimetallic persulfate soil remediation material prepared by the method of claim 1 in the remediation of soil organic pollutants.

11. The application according to claim 10, characterized in that, The organic pollutants mentioned are chlorobenzene and polychlorinated biphenyls.

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