Preparation method and apparatus for catalysts in soil pollution remediation projects
By preparing modified zinc-iron oxide mineral piezoelectric materials and an electromagnetic-piezoelectric catalytic system, the problem of uneven mechanical energy input at the soil remediation site was solved, achieving efficient, low-cost, and low-pollution soil remediation results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JINAN UNIVERSITY
- Filing Date
- 2024-01-17
- Publication Date
- 2026-06-30
AI Technical Summary
Existing piezoelectric catalysis technology struggles to achieve uniform, stable, and continuous mechanical energy input at soil remediation sites. Furthermore, the diverse types and properties of pollutants in soil lead to low efficiency, and existing technologies pose a risk of secondary pollution.
Modified zinc-iron oxide mineral piezoelectric materials were prepared using multilayer magnetically responsive zinc-iron oxide nanoblocks and brominated polyhydroxy calcium magnesium phosphate foam. Combined with an electromagnetic-piezoelectric catalytic system and a piezoelectric catalytic auxiliary system, uniform spraying of the catalyst and soil mixing were achieved through mechanical energy input.
It improves the catalytic efficiency of soil remediation materials, reduces the cost of catalyst use, reduces the risk of secondary pollution, and makes the soil remediation process simple, efficient, and adaptable to the remediation requirements of different soils.
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Figure CN117899878B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of chemical catalyst preparation and soil remediation technology, and particularly to a method and apparatus for preparing catalysts for soil pollution remediation projects. Background Technology
[0002] Soil pollution is a phenomenon caused by the introduction of harmful substances through human activities, leading to a decline in soil quality and threatening ecosystems and human health. Soil pollution has a wide and profound impact on the environment, including groundwater pollution, ecosystem destruction, decline in the quality of agricultural products, and potential threats to human health.
[0003] In order to reduce pollutant concentrations, alleviate environmental pressure, and restore the natural ecological functions of soil, there is an urgent need for an efficient, environmentally friendly, and easy-to-operate soil remediation technology.
[0004] Soil remediation technologies are mainly divided into physical remediation, chemical remediation, and bioremediation. Physical remediation technologies, such as soil replacement, deep tillage, and thermal desorption, are simple to operate and suitable for large-scale pollution treatment, but they are costly and may cause secondary pollution.
[0005] Chemical remediation technologies, such as oxidation-reduction methods, precipitation, and leaching, can treat a variety of pollutants and are fast-acting, but they are costly and may cause secondary pollution. Bioremediation technologies, including microbial remediation, phytoremediation, and animal remediation, are environmentally friendly and produce no secondary pollution, contributing to soil ecological restoration, but the remediation time is long and the effectiveness is greatly affected by environmental conditions. Piezoelectric catalysis is an emerging catalytic technology that combines the piezoelectric effect with catalytic action.
[0006] When piezoelectric catalytic materials are subjected to mechanical energy, they can generate electrical energy and release electrons or holes. These electrons or holes can participate in and accelerate redox reactions, thereby achieving catalysis.
[0007] In addition, piezoelectric catalytic materials have good stability and reusability, and therefore have received widespread attention and research. They have shown great application potential in fields such as soil remediation, degradation of organic pollutants, and hydrogen production by water splitting.
[0008] In recent years, despite the advantages of piezoelectric catalysis such as high efficiency, environmental protection, sustainability, cost saving and ease of operation, there has been little research on its application in soil remediation, and even less application in engineering.
[0009] At soil remediation sites, it is difficult to achieve uniform, stable, and continuous mechanical energy input, which seriously affects the efficiency of piezoelectric catalysis. In addition, there are many types of pollutants in the soil with different properties, and some pollutants may not be able to effectively combine with piezoelectric catalytic materials or be effectively degraded.
[0010] The environmental conditions at soil remediation sites are complex and variable, such as temperature, humidity, and pH value. Furthermore, soil remediation requires a long-term and continuous process, thus placing higher demands on the stability and lifespan of piezoelectric catalysts.
[0011] The soil pollution remediation engineering catalyst of this invention involves piezoelectric catalysis, which aims to overcome existing application difficulties, create a brand-new soil remediation technology, and promote the engineering application of piezoelectric catalysis in soil remediation. Summary of the Invention
[0012] The primary objective of this invention is to overcome the shortcomings and deficiencies of the prior art and to provide a method and apparatus for preparing catalysts for soil pollution remediation projects.
[0013] To achieve the above objectives, the present invention adopts the following technical solution:
[0014] A method for preparing catalysts for soil pollution remediation projects, characterized by the following preparation steps:
[0015] (1) Preparation of multilayer magnetically responsive zinc-iron oxide nanoblocks:
[0016] First, gum arabic, zinc nitrate, and hexamethylenetetramine are dissolved in water, and then washed by water bath and centrifugation to obtain a crystalline zinc oxide precursor. The aforementioned crystalline zinc oxide precursor is added to a sodium hydroxide solution and then placed in an autoclave for calcination to obtain zinc oxide nanoparticle powder.
[0017] Then, the aforementioned zinc oxide nanoparticle powder and iron oxide powder were dispersed in ethanol solution to obtain zinc oxide dispersion and iron oxide dispersion, respectively.
[0018] The aforementioned zinc oxide dispersion and iron oxide dispersion were sequentially added to a mixed solution of hydrochloric acid and tetraethyl orthosilicate to form a gel. After stirring and drying, multilayer magnetically responsive zinc-iron double oxide nanoblocks were obtained.
[0019] (2) Preparation of brominated polyhydroxy calcium magnesium phosphate foam:
[0020] Add calcium chloride and magnesium chloride to the polyoxyethylene-polyoxypropylene-polyoxyethylene copolymer solution and stir to mix to obtain a mixed solution;
[0021] Sodium dihydrogen phosphate dihydrate was then added to the aforementioned mixed solution, and the solution was allowed to stand, centrifuged, washed, and calcined to obtain calcium magnesium polyhydroxy phosphate.
[0022] Then, the aforementioned calcium magnesium polyhydroxyphosphate was added to the sodium fluoride and sodium bromide solutions and mixed to obtain a homogeneous mixed solution;
[0023] Then, the pH of the mixed solution is adjusted by adding ammonia or sodium hydroxide to obtain a suspension;
[0024] The suspension was transferred to an autoclave and heated, and finally washed and dried to obtain bromofluorinated polyhydroxy calcium magnesium phosphate foam.
[0025] (3) Preparation of modified zinc-iron oxide mineral piezoelectric materials:
[0026] The above-mentioned multilayer magnetically responsive zinc iron oxide nanoblocks, brominated polyhydroxy calcium magnesium phosphate foam, and chitin were dissolved in water and sonicated to obtain a dispersed mixed sol.
[0027] It was then transferred to a reactor for calcination to obtain modified zinc oxide mineral piezoelectric materials.
[0028] In detail, the gum arabic, zinc nitrate and hexamethylenetetramine are calculated in a mass ratio of 1-3:4-8:2-4;
[0029] The water bath is a 60-100℃ water bath for 10-24 hours;
[0030] The concentration of the sodium hydroxide solution is 0.2-1 mol / L;
[0031] The calcination conditions are calcination at 100-200℃ for 2-12 hours;
[0032] The ethanol solution contains ethanol and water in a volume ratio of 1:2-6.
[0033] The zinc oxide nanoparticle powder is dispersed in an ethanol solution, and the zinc oxide nanoparticle powder is calculated to be 60-90% by mass.
[0034] The iron oxide powder is dispersed in an ethanol solution, and the iron oxide powder is calculated to be 60-90% by mass.
[0035] The zinc oxide dispersion, the iron oxide dispersion, and the mixed solution of hydrochloric acid and tetraethyl orthosilicate are calculated in a volume ratio of 2-7:2-7:1.
[0036] The mixed solution of hydrochloric acid and tetraethyl orthosilicate is calculated by using hydrochloric acid with a concentration of 0.1-0.5 mol / L and tetraethyl orthosilicate in a volume ratio of 2-5:3-6.
[0037] The stirring conditions are 5-12 hours;
[0038] The drying conditions are as follows: drying at 50-75℃ for 2-6 hours.
[0039] Specifically, the concentration of the polyoxyethylene-polyoxypropylene-polyoxyethylene copolymer solution is 50-150 g / L;
[0040] The calcium chloride, magnesium chloride, and sodium dihydrogen phosphate dihydrate are calculated in a mass ratio of 2-5:4-7:4-7;
[0041] The settling condition is 12-24 hours;
[0042] The calcination conditions are calcination at 50-200℃ for 6-12 hours;
[0043] The calcium magnesium polyhydroxyphosphate was added to a sodium fluoride and sodium bromide solution in a molar ratio of calcium:fluorine:bromine = 5-15:1-5:1-5;
[0044] The pH of the mixed solution was adjusted to 10-14;
[0045] The heating conditions are heating at 200-600℃ for 12-24 hours;
[0046] The drying conditions are freeze-drying at -50 to -30°C for 6-12 hours.
[0047] In detail, the multilayer magnetically responsive zinc-iron bioxide nanoblocks, brominated polyhydroxy calcium magnesium phosphate foam, and chitin are calculated in a mass ratio of 2-5:10-15:1-3.
[0048] The ultrasound conditions are 3-10 minutes of ultrasound at a power of 75-100W.
[0049] The firing conditions are 100-500℃ for 6-12 hours.
[0050] In detail, the application device for soil pollution remediation engineering catalysts includes an electromagnetic-piezoelectric catalytic system and a piezoelectric catalytic auxiliary system. The electromagnetic-piezoelectric catalytic system consists of a soil treatment box to be remediated, an electromagnetic field generating plate, a catalyst dosing device, and an electromagnetic controller. The piezoelectric catalytic auxiliary system consists of hollow alternating pressure rollers, a drive shaft, a robotic arm, a sliding shovel, and an auxiliary controller.
[0051] In detail, the bottom of the soil treatment box to be remediated is an electromagnetic field generating plate, which is composed of 2-4 layers of stainless steel plates and 2-6 magnetizable iron blocks wound with copper coils. The coils are connected to an electromagnetic controller, and the catalyst controller controls the catalyst dosing device.
[0052] In detail, the hollow alternating pressure roller is composed of 25-30 small rollers alternatingly, each small roller being a gear-shaped structure with four notches. The drive shaft passes through the interior of the hollow alternating pressure roller. The robotic arm is equipped with a transitional movable pulley connected to the drive shaft. The shovel is composed of a pulley and a slanted shovel. The auxiliary controller controls the rotation of the hollow alternating pressure roller and controls the lifting or moving of the robotic arm along the hollow alternating pressure roller.
[0053] In detail, the catalyst dosing device consists of a pipe, a first movable pulley, a second movable pulley, a nozzle, a hose, an external water pipe, a first shut-off valve, a second shut-off valve, a catalyst tank, and a persulfate tank. The first and second movable pulleys are located at both ends of the pipe. One side of the pipe is equipped with 10-12 nozzles, and the other side is connected to a hose. The hose is connected to an external water pipe, which is connected to the catalyst tank and the persulfate tank. A first shut-off valve is located above the catalyst tank, and a second shut-off valve is located above the persulfate tank.
[0054] In detail, the specific methods for removing and remediating organic pollutants in soil are as follows:
[0055] First, the modified zinc iron oxide mineral piezoelectric material is dissolved in water and placed in a catalyst tank to obtain a catalyst solution, and a persulfate solution is placed in a persulfate tank.
[0056] Then, the catalyst liquid and persulfate solution are sprayed evenly onto the soil to be repaired in the device in sequence through the catalyst addition device of the electromagnetic-piezoelectric system, and the electromagnetic field generating plate is turned on.
[0057] The catalyst solution, persulfate solution and soil to be remediated are mixed at a volume ratio of 1-3:1-3:10-20 using a hollow alternating pressure roller of a piezoelectric catalytic auxiliary system, and the soil remediation is carried out for 2-10 hours.
[0058] After the repair is completed, the soil is removed using a sliding spade; the aforementioned catalyst solution and persulfate solution are both calculated at a mass fraction of 20-80%.
[0059] The design scheme proposed in this invention has the following beneficial effects during application:
[0060] 1. The catalyst for soil pollution remediation engineering is a modified zinc iron oxide mineral piezoelectric material. The organic combination of zinc oxide nanopiezoelectric material and iron oxide magnetic material makes the magnetic field usable as a piezoelectric source for the novel soil remediation material described in this invention, thereby improving the catalytic efficiency of the novel soil remediation material. The magnetism of the soil remediation material can be efficiently utilized through the magnetic field, which greatly reduces the cost of catalyst materials and the risk of secondary pollution.
[0061] The main component of soil remediation materials, bromofluorinated polyhydroxy calcium magnesium phosphate foam, is a bio-inorganic mineral similar to calcium hydroxyphosphate. It is environmentally friendly, can be used as a carrier to improve the stability of materials, and also has a piezoelectric effect.
[0062] Soil pollution remediation engineering equipment integrates and equips the soil remediation process, making soil remediation operations simpler and more efficient. At the same time, its adjustable systems allow it to adapt to the remediation requirements of different soils. Attached Figure Description
[0063] Figure 1 The image shows a scanning electron microscope (SEM) image of the modified zinc-iron oxide mineral piezoelectric material prepared in Example 1 of this invention.
[0064] Figure 2 X-ray diffraction (XRD) image of the modified zinc-iron oxide mineral piezoelectric material prepared in Example 1 of the present invention;
[0065] Figure 3 The hysteresis loop of the modified zinc-iron oxide mineral piezoelectric material prepared in Example 1 of this invention;
[0066] Figure 4 This is an overall diagram of the application device in Embodiment 1 of the present invention;
[0067] Figure 5 This is a schematic diagram of the application device in Embodiment 1 of the present invention;
[0068] Figure 6 This is a diagram illustrating the degradation effect of petroleum hydrocarbons in soil in Application Example 1 of the present invention.
[0069] In the diagram: 1. Soil treatment tank; 2. Electromagnetic field generating plate; 3. Magnetizable iron block; 4. Electromagnetic controller; 5. Catalyst controller; 6. Catalyst dosing device; 7. Hollow alternating pressure roller; 8. Drive shaft; 9. Robotic arm; 10. Transitional movable pulley; 11. Sliding shovel; 12. Auxiliary controller; 13. Pipeline; 14. First movable pulley; 15. Second movable pulley; 16. Nozzle; 17. Hose; 18. External water pipe; 19. First shut-off valve; 20. Second shut-off valve; 21. Catalyst tank; 22. Persulfate tank. Detailed Implementation
[0070] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0071] Example 1
[0072] Reference Figures 1-6 A method for preparing catalysts for soil pollution remediation projects, characterized by comprising the following preparation steps:
[0073] (1) Preparation of multilayer magnetically responsive zinc-iron oxide nanoblocks:
[0074] First, gum arabic, zinc nitrate, and hexamethylenetetramine are dissolved in water, and then washed by water bath and centrifugation to obtain a crystalline zinc oxide precursor. The aforementioned crystalline zinc oxide precursor is added to a sodium hydroxide solution and then placed in an autoclave for calcination to obtain zinc oxide nanoparticle powder.
[0075] Then, the aforementioned zinc oxide nanoparticle powder and iron oxide powder were dispersed in ethanol solution to obtain zinc oxide dispersion and iron oxide dispersion, respectively.
[0076] The aforementioned zinc oxide dispersion and iron oxide dispersion were sequentially added to a mixed solution of hydrochloric acid and tetraethyl orthosilicate to form a gel. After stirring and drying, multilayer magnetically responsive zinc-iron double oxide nanoblocks were obtained.
[0077] (2) Preparation of brominated polyhydroxy calcium magnesium phosphate foam:
[0078] Add calcium chloride and magnesium chloride to the polyoxyethylene-polyoxypropylene-polyoxyethylene copolymer solution and stir to mix to obtain a mixed solution;
[0079] Sodium dihydrogen phosphate dihydrate was then added to the aforementioned mixed solution, and the solution was allowed to stand, centrifuged, washed, and calcined to obtain calcium magnesium polyhydroxy phosphate.
[0080] Then, the aforementioned calcium magnesium polyhydroxyphosphate was added to the sodium fluoride and sodium bromide solutions and mixed to obtain a homogeneous mixed solution;
[0081] Then, the pH of the mixed solution is adjusted by adding ammonia or sodium hydroxide to obtain a suspension;
[0082] The suspension was transferred to an autoclave and heated, and finally washed and dried to obtain bromofluorinated polyhydroxy calcium magnesium phosphate foam.
[0083] (3) Preparation of modified zinc-iron oxide mineral piezoelectric materials:
[0084] The above-mentioned multilayer magnetically responsive zinc iron oxide nanoblocks, brominated polyhydroxy calcium magnesium phosphate foam, and chitin were dissolved in water and sonicated to obtain a dispersed mixed sol.
[0085] It was then transferred to a reactor for calcination to obtain modified zinc oxide mineral piezoelectric materials.
[0086] It should be further noted that gum arabic, zinc nitrate, and hexamethylenetetramine are calculated in a mass ratio of 1-3:4-8:2-4;
[0087] Water bath at 60-100℃ for 10-24 hours;
[0088] The concentration of sodium hydroxide solution is 0.2-1 mol / L;
[0089] The calcination conditions are 100-200℃ for 2-12 hours;
[0090] The ethanol and water in the ethanol solution are calculated in a volume ratio of 1:2-6;
[0091] Zinc oxide nanoparticles dispersed in an ethanol solution; the zinc oxide nanoparticles are calculated based on a mass fraction of 60-90%.
[0092] Iron oxide powder is dispersed in an ethanol solution. The iron oxide powder content is calculated as 60-90% by mass.
[0093] The zinc oxide dispersion, the iron oxide dispersion, and the mixed solution of hydrochloric acid and tetraethyl orthosilicate are calculated at a volume ratio of 2-7:2-7:1.
[0094] The mixed solution of hydrochloric acid and tetraethyl orthosilicate is calculated by using hydrochloric acid with a concentration of 0.1-0.5 mol / L and tetraethyl orthosilicate in a volume ratio of 2-5:3-6.
[0095] The stirring conditions are 5-12 hours;
[0096] The drying conditions are 50-75℃ for 2-6 hours.
[0097] It should be further noted that the concentration of the polyoxyethylene-polyoxypropylene-polyoxyethylene copolymer solution is 50-150 g / L;
[0098] Calcium chloride, magnesium chloride, and sodium dihydrogen phosphate dihydrate are calculated in a mass ratio of 2-5:4-7:4-7;
[0099] The settling conditions are 12-24 hours;
[0100] The calcination conditions are 50-200℃ for 6-12 hours;
[0101] Calcium magnesium polyhydroxyphosphate was added to sodium fluoride and sodium bromide solutions in a molar ratio of calcium:fluorine:bromine = 5-15:1-5:1-5;
[0102] The pH of the mixed solution was adjusted to 10-14;
[0103] The heating conditions are 200-600℃ for 12-24 hours;
[0104] The drying conditions are freeze-drying at -50 to -30°C for 6-12 hours.
[0105] It should be further noted that the multilayer magnetically responsive zinc-iron bioxide nanoblocks, brominated polyhydroxy calcium magnesium phosphate foam, and chitin are calculated in a mass ratio of 2-5:10-15:1-3.
[0106] The ultrasound conditions are 75-100W power for 3-10 minutes;
[0107] The firing conditions are 100-500℃ for 6-12 hours.
[0108] It should be further explained that the application device for a soil pollution remediation engineering catalyst includes an electromagnetic-piezoelectric catalytic system and a piezoelectric catalytic auxiliary system. The electromagnetic-piezoelectric catalytic system consists of a soil treatment box 1, an electromagnetic field generating plate 2, a catalyst dosing device 6, and an electromagnetic controller 4. The piezoelectric catalytic auxiliary system consists of a hollow alternating pressure roller 7, a drive shaft 8, a robotic arm 9, a sliding shovel 11, and an auxiliary controller 12.
[0109] It should be further noted that the bottom of the soil treatment box 1 is an electromagnetic field generating plate 2. The electromagnetic field generating plate 2 is composed of 2-4 layers of stainless steel plates and 2-6 magnetizable iron blocks 3 with copper coils wound around them. The coils are connected to the electromagnetic controller 4, and the catalyst controller 5 controls the catalyst dosing device 6. The electromagnetic generating plate 2 can generate an electromagnetic field with a magnetic field strength of 150-300mT.
[0110] It should be further explained that the hollow alternating pressure roller 7 is composed of 25-30 small rollers alternatingly, each small roller being a gear-shaped material with 4 notches. The drive shaft 8 passes through the interior of the hollow alternating pressure roller 7. The robotic arm 9 is equipped with a transitional movable pulley 10, which is connected to the drive shaft 8. The shovel 11 is composed of a pulley and a shovel. The auxiliary controller 12 controls the rotation of the hollow alternating pressure roller 7 to break up the soil to be remediated or mix the catalyst with the soil, and controls the robotic arm 9 to raise, lower, or move the hollow alternating pressure roller 7.
[0111] It should be further explained that the catalyst dosing device 6 consists of a pipe 13, a first movable pulley 14, a second movable pulley 15, a nozzle 16, a hose 17, an external water pipe 18, a first shut-off valve 19, a second shut-off valve 20, a catalyst tank 21, and a persulfate tank 22. The first movable pulley 14 and the second movable pulley 15 are located at both ends of the pipe 13. One side of the pipe 13 is equipped with 10-12 nozzles 16, and the other side is connected to a hose 17. The hose 17 is connected to an external water pipe 18, which is connected to the catalyst tank 21 and the persulfate tank 22. The catalyst tank 21 is equipped with a first shut-off valve 19, and the persulfate tank 22 is equipped with a second shut-off valve 20.
[0112] It should be further noted that the specific methods for removing and remediating organic pollutants in the soil are as follows:
[0113] First, the modified zinc iron oxide mineral piezoelectric material is dissolved in water and placed in catalyst tank 21 to obtain catalyst solution, and persulfate solution is placed in persulfate tank 22;
[0114] Then, the catalyst liquid and persulfate solution are sprayed evenly onto the soil to be repaired in the device in sequence through the catalyst addition device 6 of the electromagnetic-piezoelectric system, and the electromagnetic field generating plate 2 is turned on.
[0115] The catalyst solution, persulfate solution and soil to be remediated are mixed with the hollow alternating pressure roller 7 of the piezoelectric catalytic auxiliary system at a volume ratio of 1-3:1-3:10-20, and the soil remediation is carried out for 2-10 hours.
[0116] After the repair is completed, the soil is removed using a sliding spade 11; the aforementioned catalyst solution and persulfate solution are both calculated at a mass fraction of 20-80%.
[0117] Example 2
[0118] The preparation method of catalysts for soil pollution remediation projects includes the following preparation steps:
[0119] (1) Preparation of multilayer magnetically responsive zinc-iron oxide nanoblocks: First, gum arabic, zinc nitrate and hexamethylenetetramine were dissolved in water at a mass ratio of 3:8:4, and then stored in a water bath at 80 °C for 12 hours. After centrifugation and washing, crystalline zinc oxide precursor was obtained. The crystalline zinc oxide precursor was added to a 0.5 mol / L sodium hydroxide solution and then placed in an autoclave for 150 °C. Zinc oxide nanoparticles were prepared by calcination at ℃ for 6 hours. Then, the zinc oxide nanoparticles and iron oxide powder were dispersed in ethanol solution to obtain zinc oxide dispersion and iron oxide dispersion with a mass fraction of 80% and 80% respectively. The zinc oxide dispersion and iron oxide dispersion were added sequentially to a mixed solution of hydrochloric acid and tetraethyl orthosilicate, wherein the zinc oxide dispersion, iron oxide dispersion and the mixed solution of hydrochloric acid and tetraethyl orthosilicate were calculated in a volume ratio of 3:4:1, and the mixed solution of hydrochloric acid and tetraethyl orthosilicate was calculated in a volume ratio of 3:4 for 0.3 mol / L hydrochloric acid and tetraethyl orthosilicate. After gel formation, the mixture was stirred for 6 hours and dried at 70 ℃ for 3 hours to obtain multilayer magnetically responsive zinc-iron bioxide nanoparticles.
[0120] (2) Preparation of brominated polyhydroxy calcium magnesium phosphate foam: Calcium chloride and magnesium chloride were added to a 100 g / L polyoxyethylene-polyoxypropylene-polyoxyethylene copolymer solution and stirred to obtain a mixed solution; sodium dihydrogen phosphate dihydrate was added to the aforementioned mixed solution, wherein calcium chloride, magnesium chloride, and sodium dihydrogen phosphate dihydrate were added in a mass ratio of 3:5:5; and the solution was allowed to stand for 12 hours, centrifuged and washed, and then calcined at 150°C for 6 hours to obtain polyhydroxy calcium magnesium phosphate; then, the aforementioned polyhydroxy calcium magnesium phosphate was added to a sodium fluoride and sodium bromide solution in a molar ratio of calcium:fluorine:bromine = 7:3:3 and mixed to obtain a uniform mixed solution; then, the pH of the mixed solution was adjusted to 12 by adding ammonia or sodium hydroxide to obtain a suspension; the suspension was transferred to an autoclave and heated at 300°C for 12 hours, then washed, and then freeze-dried at -30°C for 12 hours to obtain brominated polyhydroxy calcium magnesium phosphate foam.
[0121] (3) Preparation of modified zinc iron oxide mineral piezoelectric material: The above-mentioned multilayer magnetic response zinc iron oxide nanoblocks, brominated polyhydroxy calcium magnesium phosphate foam and chitin were dissolved in water at a mass ratio of 5:10:1 and ultrasonicated at 80 W for 10 minutes to obtain a dispersed mixed sol; then it was transferred to a reaction vessel and calcined at 300 °C for 8 hours to obtain the modified zinc iron oxide mineral piezoelectric material.
[0122] The application device is the same as in Example 1.
[0123] Example 3
[0124] This implementation utilizes the modified zinc-iron oxide mineral piezoelectric material obtained in Example 1. First, the modified zinc-iron oxide mineral piezoelectric material is dissolved in water and placed in a catalyst tank to obtain a catalyst solution, while a persulfate solution is placed in a persulfate tank. Then, the catalyst solution and persulfate solution are sequentially and evenly sprayed onto the soil to be remediated using the catalyst dosing device of the electromagnetic-piezoelectric system, and the electromagnetic field generating plate is activated. The soil to be remediated is taken from a location in Zhongshan contaminated with polycyclic aromatic hydrocarbons (PAHs). Simultaneously, the catalyst solution, persulfate solution, and soil to be remediated are mixed at a volume ratio of 3:3:20 using a hollow alternating pressure roller of the piezoelectric catalytic auxiliary system, and soil remediation is carried out for 10 hours. After remediation, the soil is removed using a sliding shovel. The catalyst solution and persulfate solution are both calculated at a mass fraction of 30%. Ultimately, the removal rate of petroleum hydrocarbons in the soil reaches 90%.
[0125] Example 4
[0126] The implementation uses the modified zinc-iron oxide mineral piezoelectric material obtained in Example 2, and the soil to be remediated is soil contaminated with petroleum hydrocarbons in a certain area of Dongguan.
[0127] The catalyst solution, persulfate solution, and soil to be remediated were mixed at a volume ratio of 1:2:15 and subjected to soil remediation for 6 hours; wherein the catalyst solution and persulfate solution were both calculated as 50% by mass. Other operations were the same as in Application Example 1. Ultimately, the removal rate of petroleum hydrocarbons in the soil reached 95%.
[0128] Example 5
[0129] The implementation uses the modified zinc-iron oxide mineral piezoelectric material obtained in Example 2, and the soil to be remediated is soil contaminated with petroleum hydrocarbons in a certain area of Guangzhou.
[0130] The catalyst solution, persulfate solution, and soil to be remediated were mixed at a volume ratio of 1:1:10 and subjected to soil remediation for 5 hours; wherein, the catalyst solution and persulfate solution were both calculated as 60% by mass. Other operations were the same as in Application Example 1. Ultimately, the removal rate of petroleum hydrocarbons in the soil reached 98%.
[0131] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for the preparation of a catalyst for soil remediation engineering, characterized in that: The preparation steps include the following: (1) Preparation of multilayer magnetically responsive zinc-iron oxide nanoblocks: First, gum arabic, zinc nitrate, and hexamethylenetetramine are dissolved in water, and then washed by centrifugation in a water bath to obtain a crystalline zinc oxide precursor. The aforementioned crystalline zinc oxide precursor is added to a sodium hydroxide solution and then placed in an autoclave for calcination to obtain zinc oxide nanoparticle powder. Then, the aforementioned zinc oxide nanoparticle powder and iron oxide powder were dispersed in ethanol solution to obtain zinc oxide dispersion and iron oxide dispersion, respectively. The aforementioned zinc oxide dispersion and iron oxide dispersion were sequentially added to a mixed solution of hydrochloric acid and tetraethyl orthosilicate to form a gel. After stirring and drying, multilayer magnetically responsive zinc-iron oxide nanoblocks were obtained. (2) Preparation of brominated polyhydroxy calcium magnesium phosphate foam: Add calcium chloride and magnesium chloride to the polyoxyethylene-polyoxypropylene-polyoxyethylene copolymer solution and stir to mix to obtain a mixed solution; Add sodium dihydrogen phosphate dihydrate to the aforementioned mixed solution, let it stand, centrifuge and wash, and calcine to obtain calcium magnesium polyhydroxy phosphate. Then, the aforementioned calcium magnesium polyhydroxyphosphate was added to the sodium fluoride and sodium bromide solutions and mixed to obtain a homogeneous mixed solution; Then, the pH of the mixed solution is adjusted by adding ammonia or sodium hydroxide to obtain a suspension; The suspension was transferred to an autoclave and heated to 200-600℃. Finally, it was washed and dried to obtain bromofluorinated polyhydroxy calcium magnesium phosphate foam. (3) Preparation of modified zinc-iron oxide mineral piezoelectric materials: The multilayer magnetically responsive zinc-iron oxide nanoblocks, brominated polyhydroxy calcium magnesium phosphate foam, and chitin were dissolved in water and sonicated to obtain a dispersed mixed sol. Then it is transferred to a reactor for calcination at a temperature of 100-500℃ to obtain a modified zinc-iron oxide mineral piezoelectric material, which is the catalyst for the soil pollution remediation project.
2. The preparation method of the soil pollution remediation engineering catalyst according to claim 1, characterized in that: In step (1): The gum arabic, zinc nitrate and hexamethylenetetramine are calculated in a mass ratio of 1-3:4-8:2-4; The water bath is a 60-100℃ water bath for 10-24 hours; The concentration of the sodium hydroxide solution is 0.2-1 mol / L; The calcination conditions are calcination at 100-200℃ for 2-12 hours; The ethanol solution contains ethanol and water in a volume ratio of 1:2-6. The zinc oxide nanoparticle powder is dispersed in an ethanol solution, and the zinc oxide nanoparticle powder is calculated to be 60-90% by mass. The iron oxide powder is dispersed in an ethanol solution, and the iron oxide powder is calculated to be 60-90% by mass. The zinc oxide dispersion, the iron oxide dispersion, and the mixed solution of hydrochloric acid and tetraethyl orthosilicate are calculated in a volume ratio of 2-7:2-7:
1. The mixed solution of hydrochloric acid and tetraethyl orthosilicate is calculated by using hydrochloric acid with a concentration of 0.1-0.5 mol / L and tetraethyl orthosilicate in a volume ratio of 2-5:3-6. The stirring conditions are 5-12 hours; The drying conditions are as follows: drying at 50-75℃ for 2-6 hours.
3. The method for preparing the soil pollution remediation engineering catalyst according to claim 1, characterized in that: In step (2): The concentration of the polyoxyethylene-polyoxypropylene-polyoxyethylene copolymer solution is 50-150 g / L; The calcium chloride, magnesium chloride, and sodium dihydrogen phosphate dihydrate are calculated in a mass ratio of 2-5:4-7:4-7; The settling condition is 12-24 hours; The calcination conditions are calcination at 50-200℃ for 6-12 hours; The calcium magnesium polyhydroxy phosphate was added to a sodium fluoride and sodium bromide solution and the molar ratio of calcium:fluoride:bromine was calculated as 5-15:1-5:1-5. The pH of the mixed solution was adjusted to 10-14; The heating time is 12-24 hours; The drying conditions are freeze-drying at -50 to -30°C for 6-12 hours.
4. The method for preparing the soil pollution remediation engineering catalyst according to claim 1, characterized in that: In step (3): The multilayer magnetically responsive zinc-iron oxide nanoblocks, brominated polyhydroxy calcium magnesium phosphate foam, and chitin are calculated in a mass ratio of 2-5:10-15:1-3. The ultrasound conditions are 3-10 minutes of ultrasound at a power of 75-100W. The firing time is 6-12 hours.