CN111117630A - Microcapsule composite material for Hg-polluted soil, preparation method and repair method - Google Patents
Microcapsule composite material for Hg-polluted soil, preparation method and repair method Download PDFInfo
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- CN111117630A CN111117630A CN201911399733.6A CN201911399733A CN111117630A CN 111117630 A CN111117630 A CN 111117630A CN 201911399733 A CN201911399733 A CN 201911399733A CN 111117630 A CN111117630 A CN 111117630A
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K17/00—Soil-conditioning materials or soil-stabilising materials
- C09K17/02—Soil-conditioning materials or soil-stabilising materials containing inorganic compounds only
- C09K17/08—Aluminium compounds, e.g. aluminium hydroxide
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/08—Reclamation of contaminated soil chemically
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- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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Abstract
The invention discloses a microcapsule composite material for Hg-contaminated soil, a preparation method and a repair method, which comprise the following components in percentage by weight: 30-50% of modified clay mineral, 30-50% of calcium-magnesium based composite material and 10-30% of pH regulator. The invention is friendly to soil environment, has no secondary pollution, can not destroy the original granular structure of soil, can improve the acid-base buffering capacity of the soil to a certain extent, and improves the water retention of the soil; the treatment effect on Hg pollution in soil is obvious, the duration is long, the adaptability to external environmental factor changes is strong, and the construction is simple.
Description
Technical Field
The invention relates to the technical field of soil remediation, in particular to a microcapsule composite material for Hg-polluted soil, a preparation method and a remediation method.
Background
Mercury (Hg) can have a detrimental effect on soil health. Mercury can destroy the structure and diversity of microbial communities; resulting in a reduction in protozoan species in the soil, a reduction in diversity, and further an impact on the circulation of soil ecosystem materials and energy flow. In addition, mercury affects plant growth by affecting the physiological and biochemical processes of plants. The mercury absorbed by root system is accumulated in higher plant body, and can combine with thiol protein to change phosphate in ADP and ATP, so as to influence cell membrane permeability and inhibit mitochondrial activity. Mercury can damage the integrity of the cell membrane of the root cap, causing K in the cell+Is reduced drastically. Higher plant mercury exposure weakens leaf photosynthesis and transpiration, reduces chlorophyll synthesis and water absorption capacity, obviously reduces biomass, slows down protein synthesis speed and seriously reduces root system activity. In addition to influencing the physical and chemical properties of soil and inhibiting plant growth, mercury in soil can enter human bodies along with food chains to cause mercury poisoning. Excessive intake of mercury can affect reproduction and development, and has teratogenic, carcinogenic, mutagenic effects, and serious mental disorder.
The existing Hg-contaminated soil remediation methods comprise a physical remediation method, a heat treatment remediation method, a chemical remediation method, a biological remediation method and a plant remediation method: wherein the content of the first and second substances,
the most commonly used physical repair methods include: covering with foreign soil, deep ploughing, removing polluted soil, solidifying cement, leaching soil and physically separating. The method is mainly used for preventing and treating soil mercury pollution by reducing mercury content and mercury mobility. At present, a cement curing method is the most effective technology for treating mercury slag waste, and only in the United states, 24 percent of the total field repair amount of a heavily polluted field is repaired by the cement curing method. The physical separation method for leaching soil is to separate mercury and soil by utilizing the obvious difference of density through particle size separation, gravity separation, flotation, hydrocyclone, magnetic separation and the like. But it is not suitable for soils with high viscosity and humus.
The heat treatment restoration method is that the compound is decomposed at high temperature (600-800 ℃), so that mercury in soil is volatilized in the form of mercury elements, and the mercury concentration of the soil is reduced. When the temperature reaches 550 ℃, the mobility of Cu, Ni and Cr is reduced, and the subsequent removal of heavy metals is influenced; and high temperature can cause damage to soil structure and physicochemical properties.
The most commonly used chemical repairs include: chemical curing, soil leaching, electrokinetic remediation and the like. The main purpose is to reduce the mercury content in soil and reduce the mercury migration. The soil leaching chemical extraction technology is to leachThe agent separates the contaminants from the soil. Mercury readily reacts with sulfur-containing functional groups, halides, cyanides, etc. according to the pilson's soft and hard acid-base principle. The currently commonly used extraction liquid comprises KI, HCl, citric acid, EDTA and HNO3And the like. Wherein the KI is added with MnO in 50% HCl (V/V)2、NaNO3、CuSO4The post-leaching effect is most remarkable, and the leaching agent can be reused after being treated by scrap iron, but the leaching agent can influence the physicochemical property of soil. The electrokinetic remediation is a remediation technology for removing toxic substances in soil through electrophoresis/electromigration and electrolysis by introducing current into a soil medium. This technology is mainly directed to charged ions, complexes and colloids. The mercury in the soil has various attached forms, and part of the mercury is insoluble substances, so that the key point of the technology is to enhance the mobility of the mercury in the soil. The currently common method is to add chemical agents, which are commonly: EDTA, Cl－、I－、OH－And the like. Electrokinetic remediation is susceptible to other factors such as soil pH, nutrients, and the like. The traditional physical and chemical remediation method is greatly restricted by the environment, and can affect the physical and chemical properties of soil to cause secondary pollution.
The bioremediation method utilizes biological characteristics to repair polluted soil, and the basic principle is the absorption, enrichment or degradation of pollutants by animals, plants and microorganisms. The bioremediation method is widely concerned by the academic world due to the advantages of small side effect, low cost, eco-friendliness and the like. Bioremediation includes phytoremediation, microbial remediation.
The plant repairing method comprises three methods, namely plant immobilization, plant extraction and plant volatilization. Plant immobilization refers to the process of absorbing, precipitating and passivating mercury in soil by partial mercury-resistant plants. The mercury-resistant plant can combine mercury with anionic compounds (carbonate, sulfate, phosphate, etc.) of root cell wall and ligands in cellulose, lignin, pectin, etc. to form precipitate or stable compound to fix mercury on root cell wall. Hg into cells2+Binding to Phytochelatins (PCs) produces a less toxic Hg-PC complex that is stored in the vacuole. In order to increase the content of available mercury in soil and improve the fixation efficiency of plants on mercury, partial research is carried outSome methods have been introduced to improve, such as increasing soluble mercury in soil by composting. The plant extraction and restoration are mainly embodied in the overground part of the plant, wherein the main mercury enrichment places are near the inner cortex of the plant root besides cell walls and vacuoles. Researches find that synthetic substrates of PCs, namely Glutathione (GSH), are transported to PCs in the underground part after being produced in the overground part, so that the toxicity of mercury can be greatly reduced, and the mercury enrichment capacity of plants is improved. Plant volatilization mainly occurs in leaves, the transformation mechanism of mercury in the plant leaves is not clear at present, and researches show that the volatilization of mercury in the plant leaves is influenced by illumination and temperature. At present, excellent mercury hyper-enrichment plants are not found, and the plants are selected preferentially to plants with larger biomass, so that the problems of difficult collection of volatile Hg and treatment of plant biomass are caused. Furthermore, the plants found have limited tolerance to heavy metal contaminants, resulting in phytoremediation being only suitable for moderate contamination level soil remediation; and the hyper-enriched plant is short and small, slow in growth, limited in root system extension depth, low in restoration efficiency and long in period. Therefore, the microbial remediation method which has strong adaptability, low cost, no secondary pollution, wide application range and ecological friendliness becomes a research hotspot in recent years.
Disclosure of Invention
Aiming at the defects in the problems, the invention provides a microcapsule composite material for Hg-polluted soil, a preparation method and a repair method.
The invention aims to provide a microcapsule composite material for Hg-contaminated soil, which comprises the following components in percentage by weight:
30-50% of modified clay mineral, 30-50% of calcium-magnesium based composite material and 10-30% of pH regulator.
As a further improvement of the invention, the modified clay mineral is a modified zeolite.
As a further improvement of the invention, the calcium-magnesium based composite material comprises one or more of calcium magnesium phosphate fertilizer and calcium superphosphate.
As a further improvement of the invention, the pH adjusting agent comprises one or more of heavy magnesium oxide and hydrated lime.
A second object of the present invention is to provide a method for preparing a microcapsule composite material, comprising:
modifying clay mineral by heat to obtain modified clay mineral;
and mixing the modified clay mineral, the calcium-magnesium based composite material and the pH regulator according to a preset proportion to prepare the microcapsule composite material.
As a further improvement of the present invention, a process for producing the modified clay mineral, comprising:
naturally drying, crushing and sieving the clay mineral to obtain a clay mineral pretreatment product;
carrying out heat treatment on the clay mineral pretreatment product to obtain a clay mineral heat treatment product; wherein the temperature of the heat treatment is 200-500 ℃, and the time of the heat treatment is 4-6 hours;
and cooling the clay mineral heat treatment product to obtain the modified clay mineral.
The third purpose of the invention is to provide a repairing method of the microcapsule composite material, which comprises the following steps:
detecting the total amount of Hg in the polluted soil and the effective state of the Hg;
uniformly spraying the microcapsule composite material on the surface of the polluted soil to be treated according to the analysis and detection result of the polluted soil and the standard required to be achieved and the adding proportion of 0.1-0.8% of the mass of the Hg-polluted soil;
according to the characteristics of the polluted soil, turning over and mixing, and adding pollution-free clean water after uniformly mixing;
keeping the water content of 20-30% for 1-3 months, fully reacting the microcapsule composite material with heavy metal Hg, performing dynamic detection, and starting normal planting after sampling detection is qualified.
Compared with the prior art, the invention has the beneficial effects that:
the invention is friendly to soil environment, has no secondary pollution, can not destroy the original granular structure of soil, can improve the acid-base buffering capacity of the soil to a certain extent, and improves the water retention of the soil; the treatment effect on Hg pollution in soil is obvious, the duration is long, the adaptability to external environmental factor changes is strong, and the construction is simple.
Drawings
FIG. 1 is a schematic diagram of effective state concentration of soil Hg after being repaired by a microcapsule composite material according to an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The invention is described in further detail below with reference to the attached drawing figures:
the invention provides a microcapsule composite material for Hg-contaminated soil, which is friendly to soil environment, has no secondary pollution, does not destroy the original granular structure of soil, can improve the acid-base buffering capacity of the soil to a certain extent, and improves the water retention of the soil; the treatment effect on Hg pollution in soil is obvious, the duration is long, the adaptability to external environmental factor changes is strong, and the construction is simple; comprises the following components in percentage by weight:
30-50% of modified clay mineral, 30-50% of calcium-magnesium based composite material and 10-30% of pH regulator.
Wherein:
the modified clay mineral is formed by thermally modifying clay mineral, and the modified clay mineral can adopt other modified clay minerals with larger specific surface area besides modified zeolite. The natural zeolite of the invention comprises one or a mixture of more than one of analcime, heulandite, scolecite, natrolite, chabazite, mordenite and clinoptilolite.
The function of adding the modified zeolite is as follows: the zeolite powder has a plurality of crystal holes and pore channels which are arranged orderly on the surface, has a large specific surface area, can contain a large amount of trace elements in the zeolite powder, has a good adsorption effect on heavy metals, and has the adsorption effect far exceeding that of active carbon and a specific natural molecular sieve. The zeolite molecular sieve is modified by a thermal modification mode, the impurity content on the surface of the modified zeolite material is reduced, the blocked pore channel is dredged, the specific surface area of the repairing material is further increased, the adsorption capacity is improved, and the adsorption capacity of the repairing material on heavy metals is improved; through the control of the modification temperature and time, the pore structure on the surface of the zeolite material is improved to change, the adsorption efficiency of the zeolite material on heavy metal is improved, the adsorption pertinence of the zeolite material on heavy metal Hg is stronger, and the purification effect of the repair material on the heavy metal is improved; meanwhile, the clay mineral with high surface area has a porous channel, so that the composite material can conveniently perform ion exchange with heavy metal Hg.
The calcium-magnesium-based composite material comprises one or more of calcium-magnesium phosphate fertilizer and calcium superphosphate, can provide phosphate ions, is alkaline, and can be used for adjusting and repairing soil.
The pH regulator comprises one or more of heavy magnesium oxide and hydrated lime, can regulate the pH value of soil when mixed in the soil, and can ensure that the pH value in the soil is increased by about 0.1-0.3, so that the soil stably maintains a weakly alkaline environment and the acid-base environment of the soil is not damaged.
The invention provides a preparation method of a microcapsule composite material, which comprises the following steps:
s1, performing thermal modification on the clay mineral to obtain a modified clay mineral;
the specific preparation method of the modified clay mineral comprises the following steps:
1) and (3) pretreatment: naturally drying and crushing the clay mineral, and sieving the clay mineral by a 200-mesh sieve to obtain a clay mineral pretreatment product;
2) and (3) heat treatment: carrying out heat treatment on the clay mineral pretreatment product to obtain a clay mineral heat treatment product; wherein the heat treatment temperature is 200-500 ℃, and the heat treatment time is 4-6 hours;
3) and cooling treatment: and (3) putting the clay mineral heat treatment product into a dryer for cooling to obtain the modified clay mineral.
S2, preparing a calcium magnesium base composite material;
s3, mixing the modified clay mineral, the calcium-magnesium based composite material and the pH regulator according to a preset proportion to obtain the microcapsule composite material.
The invention provides a repairing method of a microcapsule composite material, which comprises the following steps:
s1, detecting the total amount and effective state of Hg in the polluted soil;
s2, uniformly spraying the microcapsule composite material on the surface of the polluted soil to be treated according to the analysis and detection result of the polluted soil and the standard required to be met and the adding proportion of 0.1-0.8% of the mass of the Hg-polluted soil;
s3, ploughing and mixing according to the characteristics of the polluted soil, and adding pollution-free clean water after uniformly mixing;
s4, keeping the water content of 20-30% for 1-3 months, making the microcapsule composite material fully react with heavy metal Hg, carrying out dynamic detection, and starting normal planting after sampling detection is qualified.
The method specifically comprises the following steps:
aiming at dry farmland:
s11, detecting the total amount and effective state of Hg in the polluted soil;
s12, ploughing the contaminated soil of the plough layer of 0-20cm, removing branches and gravels, and crushing soil blocks, wherein the diameter of the crushed soil is less than 1 cm;
s13, uniformly spraying the microcapsule composite material on the surface of the polluted soil to be treated according to the analysis and detection result of the polluted soil and the standard required to be met and the adding proportion of 0.1-0.8% of the mass of the Hg-polluted soil;
s14, uniformly mixing the polluted soil and the repairing material, and adding 20-30% of pollution-free clean water after uniform mixing;
s15, keeping the water content of 20-30% for 1-3 months, making the microcapsule composite material fully react with heavy metal Hg, carrying out dynamic detection, and starting normal planting after sampling detection is qualified.
When aiming at paddy field:
s21, detecting the total amount and effective state of Hg in the polluted soil;
s22, performing ploughing operation;
s23, uniformly spraying the microcapsule composite material on the surface of the polluted soil to be treated according to the analysis and detection result of the polluted soil and the standard required to be met and the adding proportion of 0.1-0.8% of the mass of the Hg-polluted soil;
s24, covering the renovation material on the ploughed soil surface, ploughing again and stirring to uniformly mix the renovation material and the polluted soil;
and S25, standing the soil for 1-3 months, fully reacting the microcapsule composite material with heavy metal Hg, carrying out dynamic detection, and starting normal planting after sampling detection is qualified.
Example 1:
in the experimental sample, the total amount of Hg in a soil sample is detected by a method specified in soil environment quality agricultural land soil pollution risk control standard (GB15618-2018) in a Hg-polluted farmland in a certain region of Jiangsu; the effective state concentration of the mercury in the soil is detected by adopting a DTPA-TEA-calcium chloride method for leaching and adopting a method specified in determination of mercury, arsenic, selenium, bismuth and antimony in water by an atomic fluorescence method (HJ 694-2014). The detection result shows that the pollution concentration of the farmland site is that the total Hg content is 0.6-0.8mg/kg, the pH value is 6.2-6.5, and the soil remediation goal is that the effective state concentration of Hg in soil is reduced by 30% after the passivation stabilization technology.
The invention provides a microcapsule composite material of Hg-contaminated soil, which comprises the following components in percentage by weight:
50% of modified zeolite (mineral microcapsule), 30% of calcium magnesium phosphate fertilizer, 10% of heavy magnesium oxide and 10% of hydrated lime.
The invention provides a method for restoring Hg-contaminated soil, which comprises the following steps:
s1, taking 100kg of the polluted soil of the farmland, putting 0.3kg of the prepared microcapsule composite material, and uniformly spraying the microcapsule composite material on the surface of the soil;
s2, stirring to fully and uniformly mix the microcapsule composite material with the polluted soil, then adding water, and stirring for 1-2 times, wherein the water content in the soil is kept above 30%;
and S3, covering a black plastic film on the soil, and keeping the water content at about 30%. Respectively carrying out sampling detection when the maintenance is carried out for 10, 20, 30, 60 and 120 days;
the results of detection of S4 and Hg are shown in Table 1
TABLE 1 initial concentration of Hg in soil at available state
| Time of day | Concentration of effective state ug/kg | Rate of passivation |
| Day 0 | 1.52 | 0.00％ |
| 10 days | 1.12 | 26.32％ |
| 20 days | 0.92 | 39.47％ |
| 30 days | 0.72 | 52.63％ |
| 60 days | 0.69 | 54.61％ |
| 120 days | 0.68 | 55.26％ |
The initial effective concentration of Hg in the soil is 1.52ug/kg, and when the soil is maintained for 120 days, the effective concentration of Hg in the soil is 0.92ug/kg, and the effective concentration of Hg is reduced by 55.26%. Has fallen below the repair target value of 30% reduction in the active state.
Example 2:
the sample is from a farmland in certain area in Guangxi, and the total amount of Hg in the soil sample is detected by a method specified in soil environment quality agricultural land soil pollution risk control standard (GB 15618-2018); leaching by adopting a calcium chloride method, and detecting the effective state concentration of the mercury in the soil by adopting a method specified in determination of mercury, arsenic, selenium, bismuth and antimony in water by an atomic fluorescence method (HJ 694-2014). The detection result shows that the pollution concentration of the farmland site is that the total Hg content is 1.2-2.0 mg/kg, the pH value is 6.4-7.9, and the soil remediation goal is that the effective state concentration of Hg in soil is reduced by 30% after the passivation stabilization technology is adopted.
The invention provides a microcapsule composite material of Hg-contaminated soil, which comprises the following components in percentage by weight:
30% of modified zeolite, 20% of calcium magnesium phosphate fertilizer, 20% of calcium superphosphate, 20% of heavy magnesium oxide and 10% of hydrated lime.
The invention provides a method for restoring Hg-contaminated soil, which comprises the following steps:
s1, taking 50kg of the polluted soil of the farmland, putting 0.15kg of the prepared microcapsule composite material, and uniformly spraying the microcapsule composite material on the surface of the soil;
s2, stirring to fully and uniformly mix the microcapsule composite material with the polluted soil, then adding water, and stirring for 1-2 times, wherein the water content in the soil is kept above 30%;
and S3, covering a black plastic film on the soil, and keeping the water content at about 30%. Respectively carrying out sampling detection when the maintenance is carried out for 10, 20, 30, 60 and 120 days;
the results of detection of S4 and Hg are shown in Table 2
TABLE 2 initial concentration of Hg in soil in effective state
| Time of day | Concentration of effective state ug/kg | Rate of passivation |
| Day 0 | 2.45 | 0.00％ |
| 10 days | 2.08 | 20.41％ |
| 20 days | 1.84 | 27.35％ |
| 30 days | 1.75 | 29.80％ |
| 60 days | 1.73 | 33.06％ |
| 120 days | 1.69 | 32.65％ |
The initial effective concentration of Hg in the soil is 2.45ug/kg, and when the soil is maintained for 120 days, the effective concentration of Hg in the soil is 1.69ug/kg, and the effective concentration of Hg is reduced by 32.65%. Has fallen below the repair target value of 30% reduction in the active state.
Example 3:
the sample is from a farmland in certain Shaoxing region, and the total amount of Hg in the soil sample is detected by a method specified in soil environment quality agricultural land soil pollution risk control standard (GB 15618-2018); leaching by adopting a 0.1mol/L hydrochloric acid method, and detecting the effective state concentration of the mercury in the soil by adopting a method specified in determination of mercury, arsenic, selenium, bismuth and antimony in water by an atomic fluorescence method (HJ 694-2014). The detection result shows that the pollution concentration of the farmland site is that the total Hg content is 0.8-1.6mg/kg, the pH value is 5.8-7.4, and the soil remediation goal is that the effective state concentration of Hg in soil is reduced by 30% after the passivation stabilization technology.
The invention provides a microcapsule composite material of Hg-contaminated soil, which comprises the following components in percentage by weight:
40% of modified zeolite, 30% of calcium magnesium phosphate fertilizer, 20% of calcium superphosphate and 10% of heavy magnesium oxide.
The invention provides a method for restoring Hg-contaminated soil, which comprises the following steps:
s1, taking 100kg of the polluted soil of the farmland, putting 0.3kg of the prepared microcapsule composite material, and uniformly spraying the microcapsule composite material on the surface of the soil;
s2, stirring to fully and uniformly mix the microcapsule composite material with the polluted soil, then adding water, and stirring for 1-2 times, wherein the water content in the soil is kept above 30%;
and S3, covering a black plastic film on the soil, and keeping the water content at about 30%. Respectively carrying out sampling detection when the maintenance is carried out for 10, 20, 30, 60 and 120 days;
the results of detection of S4 and Hg are shown in Table 3
TABLE 3 initial concentration of Hg in soil in effective state
| Time of day | Concentration of effective state ug/kg | Rate of passivation |
| Day 0 | 1.82 | 0.00％ |
| 10 days | 1.51 | 17.03％ |
| 20 days | 1.35 | 25.82％ |
| 30 days | 1.26 | 30.77％ |
| 60 days | 1.22 | 32.97％ |
| 120 days | 1.21 | 33.52％ |
The initial effective concentration of Hg in the soil is 1.82ug/kg, and when the soil is maintained for 120 days, the effective concentration of Hg in the soil is 1.21ug/kg, and the effective concentration of Hg is reduced by 33.52%. Has fallen below the repair target value of 30% reduction in the active state.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. The microcapsule composite material for Hg-contaminated soil is characterized by comprising the following components in percentage by weight:
30-50% of modified clay mineral, 30-50% of calcium-magnesium based composite material and 10-30% of pH regulator.
2. The microcapsule composite of claim 1, wherein the modified clay mineral is a modified zeolite.
3. The microcapsule composite of claim 1, wherein the calcium magnesium based composite comprises one or more of a calcium magnesium phosphate fertilizer and a calcium superphosphate.
4. The microcapsule composite of claim 1, wherein the pH-adjusting agent comprises one or more of heavy magnesium oxide and hydrated lime.
5. A process for preparing a microcapsule composite according to any one of claims 1 to 4, comprising:
modifying clay mineral by heat to obtain modified clay mineral;
and mixing the modified clay mineral, the calcium-magnesium based composite material and the pH regulator according to a preset proportion to prepare the microcapsule composite material.
6. The method according to claim 5, wherein the modified clay mineral is prepared by a method comprising:
naturally drying, crushing and sieving the clay mineral to obtain a clay mineral pretreatment product;
carrying out heat treatment on the clay mineral pretreatment product to obtain a clay mineral heat treatment product; wherein the temperature of the heat treatment is 200-500 ℃, and the time of the heat treatment is 4-6 hours;
and cooling the clay mineral heat treatment product to obtain the modified clay mineral.
7. A method of repairing a microcapsule composite according to any one of claims 1 to 4, comprising:
detecting the total amount of Hg in the polluted soil and the effective state of the Hg;
uniformly spraying the microcapsule composite material on the surface of the polluted soil to be treated according to the analysis and detection result of the polluted soil and the standard required to be achieved and the adding proportion of 0.1-0.8% of the mass of the Hg-polluted soil;
according to the characteristics of the polluted soil, turning over and mixing, and adding pollution-free clean water after uniformly mixing;
keeping the water content of 20-30% for 1-3 months, fully reacting the microcapsule composite material with heavy metal Hg, performing dynamic detection, and starting normal planting after sampling detection is qualified.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112779022A (en) * | 2021-01-15 | 2021-05-11 | 清华大学 | Heavy metal contaminated soil remediation agent and preparation method and application thereof |
| CN113735485A (en) * | 2021-09-07 | 2021-12-03 | 青岛理工大学 | Environment complex response homogeneous expansion type self-repairing microcapsule for concrete and preparation method thereof |
| CN115232627A (en) * | 2021-04-23 | 2022-10-25 | 浙江中地净土科技有限公司 | Soil improvement composite material applied to clay soil heavy metal pollution |
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| CN113735485A (en) * | 2021-09-07 | 2021-12-03 | 青岛理工大学 | Environment complex response homogeneous expansion type self-repairing microcapsule for concrete and preparation method thereof |
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