Preparation Method and Application of a Heavy Metal Pollution Remediation Material

Abstract

The present invention relates to the technical field of remediation of heavy metal pollution in soil or water bodies, and specifically to a preparation method and application of a heavy metal pollution remediation material. An alkali solution is added to an iron salt aqueous solution, and the reaction is carried out at 30-60 °C for 0.15-1 h to obtain dispersion liquid I; a blocking agent solution is added to dispersion liquid I, and the reaction is carried out at 30-60 °C for 1-3 h; then the alkali solution is added again, and the reaction is continued at 30-90 °C for 0.2-1 h to obtain dispersion liquid II; a grafting agent is added to dispersion liquid II, and the reaction is carried out at 50-90 °C for 0.5-2 h. After the reaction is completed, the obtained mixture is subjected to solid-liquid separation, or dried after solid-liquid separation to obtain the heavy metal pollution remediation material. The present invention can prepare a heavy metal pollution remediation material with controllable particle size and a highly active reaction layer on the surface through a simple preparation route by the "blocking-grafting" technology. It has a high passivation rate for heavy metal ions and can be used for the remediation of heavy metal-polluted soil and heavy metal-polluted water bodies.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil or water body heavy metal pollution remediation, and particularly relates to a preparation method and application of a heavy metal pollution remediation material. Background Art

[0002] Heavy metal pollution of soil and water bodies has a great impact on crop and food safety, directly threatening human health. It is urgent to accelerate the remediation of polluted soil and water bodies and realize the safe utilization of soil and water bodies.

[0003] Compared with water body heavy metal pollution, soil heavy metal pollution is more concealed, and due to the complexity of the soil environment, it is more difficult to remove heavy metal pollutants. At present, scholars have studied various methods, such as soil replacement / soil replacement method, leaching method, electro-remediation method, passivation method, etc. However, limited by many factors such as construction difficulty, remediation effect, and remediation cost, few remediation technologies have been widely applied. Among these methods, in-situ passivation method for remediating heavy metal polluted soil has the advantages of simple construction and fast response speed, and is a method with great promise for wide application. Using in-situ passivation remediation can reduce the transport and accumulation of heavy metals in plants while playing a good stabilizing role in the soil structure. The potential mechanisms of different passivation materials are different, resulting in different passivation effects.

[0004] At present, common in-situ passivation materials mainly include inorganic, organic, inorganic-organic composite, and new nano-materials emerging in recent years. Inorganic materials mainly include phosphorus-containing materials, lime materials, silicate materials, metals and their oxide materials. Organic materials mainly include crop straws, organic fertilizers, and biochar. Inorganic-organic composite materials are mainly composites composed of inorganic and organic passivation materials in a certain ratio. New nano-passivation materials mainly include nano-materials, mesoporous materials, functional membrane materials, and plant polyphenol substances, etc. Common phosphorus-containing materials include phosphoric acid, calcium magnesium phosphate fertilizer, apatite, etc. Research shows that the heavy metal background values in some phosphorus-containing materials are relatively high. Excessive application is likely to increase the total amount and available content of soil heavy metals, and the excessive presence of soluble phosphorus in the soil will lead to the loss of available phosphorus, causing eutrophication of nearby water bodies. Common lime substances include lime, calcium hydroxide, calcium magnesium oxides, carbonate minerals, calcium magnesium carbonate minerals, dolomite, calcite, etc. The application of lime passivation materials has the most direct reaction on the soil, which is to increase the soil pH value and generate a large amount of OH －, which promotes the adsorption of heavy metals by soil colloids and clay particles. However, excessive application of lime-based passivation materials can also have negative impacts on soil quality, causing the rapid decomposition of soil organic matter, easily forming a precipitation layer of calcium carbonate and calcium hydroxide cementation under the topsoil layer, and even leading to over-liming of the soil, resulting in the long-term maintenance of a high concentration of heavy metal ions in the soil. The long-term application of lime can also damage the soil aggregate structure, have a negative impact on the abundance and community structure of indigenous microorganisms, easily lead to soil compaction and nutrient loss, and cause a lack of trace elements in the soil. Common silicate passivation materials include sepiolite, palygorskite, kaolinite, montmorillonite, bentonite, etc. When silicates are used to repair heavy metal pollution in cultivated land, there are problems such as high cost, large application amount, and short effect maintenance time, which are not conducive to promotion and long-term use.

[0005] The solidification / stabilization remediation technology reduces the mobility of heavy metal ions through the reaction between the remediation material and heavy metal ions, realizing the solidification / stabilization of heavy metal ions in the soil. The core of the solidification / stabilization remediation technology is the development of remediation materials. Compared with many remediation materials, iron oxides are widely distributed in nature and play an important role in geochemistry. Some studies have shown that iron oxides have various effects such as enhancing soil mechanical stability, fixing soil organic matter, and improving soil buffering capacity. Many scholars have tried to use iron oxides for the passivation remediation of heavy metal contaminated soils. However, the passivation efficiency of natural iron oxides or pure iron oxide materials is not sufficient to meet the performance requirements of current passivation materials. Therefore, artificial modification is often carried out to improve their heavy metal passivation performance. Chinese Patent Application (Application No. 202210471194.8) discloses a nano-iron oxide composite material that can treat soil arsenic pollution. This material mainly includes nano-iron oxide loaded on biomass carbon, nano-iron oxide loaded with citric acid, wollastonite or diatomite, and the maximum reduction rate of arsenic can reach 70%. However, the preparation process of this remediation agent is cumbersome, difficult to scale up production, and only effective for arsenic, making it difficult to treat the widespread combined pollution. Summary of the Invention

[0006] Aiming at the deficiencies in the above-mentioned existing technologies and products, the present invention provides a preparation method and application of a heavy metal pollution remediation material. Through the "interception-grafting" technology, a heavy metal pollution remediation material with controllable particle size and a highly active reaction layer on the surface is prepared by a simple preparation route. It has a high passivation rate for heavy metals and can be used for the remediation of heavy metal contaminated soils and heavy metal contaminated water bodies.

[0007] The present invention is specifically realized through the following technical solutions. A preparation method of a heavy metal pollution remediation material proposed according to the present invention includes the following steps:

[0008] (1) Dissolve an iron salt in water to prepare an iron salt aqueous solution, where the iron salt is ferrous sulfate, ferric sulfate, ferrous chloride, or ferric chloride;

[0009] (2) Slowly add an alkali solution drop by drop to the iron salt aqueous solution in step (1), such that the molar ratio of OH - in the alkali solution added in step (2) to Fe 3+ or Fe 2+ in the iron salt aqueous solution in step (1) is 1:0.5 - 5. After the addition is complete, react at 30 - 60 °C for 0.15 - 1 h to obtain dispersion I;

[0010] (3) Dissolve a blocking agent in deionized water and then add it drop by drop to dispersion I obtained in step (2). After the addition is complete, react at 30 - 60 °C for 1 - 3 h; then continue to add an alkali solution drop by drop to the resulting reaction mixture to ensure that the total molar ratio of OH - in the alkali solutions added in steps (2) and (3) to Fe 3+ or Fe 2+ in the iron salt aqueous solution in step (1) is 1:0.3 - 0.5. After the addition is complete, continue to react at 30 - 90 °C for 0.2 - 1 h to obtain dispersion II;

[0011] (4) Dissolve or disperse a grafting agent in deionized water, absolute ethanol, or an ethanol aqueous solution, and then slowly add it drop by drop to dispersion II. React at 50 - 90 °C for 0.5 - 2 h. After the reaction is complete, perform solid-liquid separation on the resulting mixture, or perform drying after solid-liquid separation to obtain the heavy metal pollution remediation material.

[0012] Preferably, the concentration of the iron salt aqueous solution in step (1) is 0.3 - 1.3 mol / L.

[0013] Preferably, the alkali solution in steps (2) and (3) is sodium hydroxide solution, potassium hydroxide solution, ammonia water solution, or calcium hydroxide solution. The concentration of the sodium hydroxide solution, potassium hydroxide solution, and calcium hydroxide solution is 6 - 15 mol / L, and the mass percentage of the ammonia water solution is 18 - 25%.

[0014] Preferably, the blocking agent is one or more of glycerol, fatty acid glyceride, sodium dodecylbenzenesulfonate, and sodium fatty alcohol polyoxyethylene ether sulfate. The added mass of the blocking agent is 0.1 - 0.5% of the mass of dispersion I.

[0015] Preferably, the grafting agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, dithiocarbamate, and ethylenediamine. The molar ratio of the grafting agent to Fe 3+ or Fe 2+The molar ratio is 0.01~0.3:1.

[0016] Preferably, the aqueous ethanol solution described in step (4) is obtained by mixing absolute ethanol and deionized water, and the volume fraction of absolute ethanol in the aqueous ethanol solution is 10~90%.

[0017] Preferably, the solid-liquid separation described in step (4) is carried out by filtration or centrifugation, and the drying is carried out by vacuum drying or spray drying.

[0018] The primary particle size of the heavy metal pollution remediation material obtained by the foregoing preparation method is 20~200 nm, and its secondary particle size is 5~50 μm.

[0019] The present invention also provides a heavy metal pollution remediation material obtained according to the foregoing preparation method and its application in the treatment of heavy metal-polluted soil or heavy metal-polluted water body. When it is used for the remediation of heavy metal-polluted soil, the added mass is 0.5~3% of the soil mass. When it is used for the treatment of heavy metal-polluted water body, the added mass concentration in the heavy metal-polluted water body is 0.1~5 g / L.

[0020] Compared with the prior art, the present invention has obvious advantages and beneficial effects. By means of the above technical solutions, the present invention can achieve considerable technical progressiveness and practicability, and has wide utilization value. It has at least the following advantages:

[0021] (1) In the present invention, a blocking agent is added after the iron salt and the alkali solution form iron hydroxide particles to prevent further dehydration condensation between iron hydroxide molecules and prevent particle aggregation. Then, an alkali solution is added again to promote the further formation of iron hydroxide. Finally, a grafting agent is added to modify the material, so that the surface of the material is loaded with active groups, promoting the adsorption and passivation of heavy metals. Through the "blocking-grafting" technology, the present invention can prepare a heavy metal pollution remediation material with controllable particle size and a highly active reaction layer on the surface by adjusting the addition amount and addition timing of the blocking agent.

[0022] (2) The surface of the highly active heavy metal pollution remediation material prepared by the present invention is uniformly distributed with a large number of pores, which is helpful for the adsorption and fixation of heavy metal ions. The primary particle size of the material is 20~200 nm, and the secondary particle size is 5~50 μm, and the particle size distribution is uniform. Compared with ordinary remediation agents, it has higher adsorption activity, and a higher remediation effect on heavy metals can be achieved at a lower addition dose. The highly active heavy metal pollution remediation material prepared by the present invention can not only be used for the remediation of heavy metal-polluted soil, but also for the treatment of heavy metal-polluted water body, and the highly active heavy metal pollution remediation material has multiple effects, and can simultaneously adsorb multiple heavy metal ions such as Pb, Cd, Cu, and As. Description of the Drawings

[0023] Figure 1It is a comparison chart of the content changes of heavy metals Pb, Cd, and As in the soil leachate before and after the remediation of contaminated soil by the highly active heavy metal contaminated soil remediation material prepared in Example 1 and the ordinary remediation material.

[0024] Figure 2 It is a transmission electron microscope image of the highly active heavy metal contaminated soil remediation material prepared in Example 2.

[0025] Figure 3 It is a scanning electron microscope image of the highly active heavy metal contaminated soil remediation material prepared in Example 3 at a magnification of 500 times.

[0026] Figure 4 It is a scanning electron microscope image of the highly active heavy metal contaminated soil remediation material prepared in Example 3 at a magnification of 5000 times.

[0027] Figure 5 It is a water dispersion particle size distribution chart of the highly active heavy metal contaminated soil remediation material prepared in Example 4. Detailed implementation manners

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] The present invention will be described in detail below with specific examples. For those not specified in the following examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For raw materials and reagents without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase. The heating method in the following examples can be water bath heating, or devices such as a magnetic stirrer with heating function and a heating jacket can be used. The heating methods described in the examples are not regarded as limitations to the present invention.

[0030] Example 1:

[0031] (1) Weigh 77.5 g of ferrous chloride tetrahydrate (FeCl2·4H2O), dissolve it in 300 mL of water to obtain an aqueous solution of ferrous chloride, and place the aqueous solution of ferrous chloride in a constant temperature water bath at 40 °C to heat it to 40 °C.

[0032] (2) Dissolve 80 g of sodium hydroxide (NaOH) in a certain amount of water, and then make up the volume to 200 mL to obtain a 10 mol / L NaOH solution; take 40 mL of the above NaOH solution and add it dropwise to the aqueous solution of ferrous chloride in step (1). After the addition is complete, stir and react in a constant temperature water bath at 40 °C for 10 min to obtain dispersion A.

[0033] (3) Weigh 1.5 g of fatty acid glyceride, disperse it evenly in 15 g of water, and then add it dropwise to dispersion A. After the addition is complete, stir and react in a constant temperature water bath at 40 °C for 1 h. Subsequently, continue to add 80 mL of the 10 mol / L NaOH solution prepared in step (2) dropwise to the obtained reaction mixture. After the addition is complete, continue to stir and react in a constant temperature water bath at 40 °C for 0.5 h to obtain dispersion B.

[0034] (4) Weigh 12 g of sodium dimethyldithiocarbamate, dissolve it in 12 g of an ethanol aqueous solution with a volume fraction of 50%, and then add it dropwise to dispersion B. Subsequently, heat the reaction system to 80 °C (it can be heated with a water bath) and stir and react for 2 h. After the reaction is complete, filter the obtained mixture, and the obtained filter cake is the high-activity heavy metal pollution remediation material.

[0035] Comparative Example 1:

[0036] Preparation of ordinary remediation material:

[0037] (1) Weigh 77.5 g of ferrous chloride tetrahydrate (FeCl2·4H2O), dissolve it in 300 mL of water to obtain an aqueous solution of ferrous chloride, and place the aqueous solution of ferrous chloride in a constant temperature water bath at 40 °C to heat it to 40 °C.

[0038] (2) Dissolve 80 g of sodium hydroxide (NaOH) in water, make up the volume to 200 mL to obtain a 10 mol / L NaOH solution; take 120 mL of the above NaOH solution and add it dropwise to the aqueous solution of ferrous chloride in step (1). After the addition is complete, stir and react in a constant temperature water bath at 40 °C for 20 min. After the reaction is complete, filter the obtained dispersion, and the obtained filter cake is the ordinary remediation material.

[0039] According to the Soil Environmental Monitoring Technical Specification (HJ / T166 - 2004) issued by the Ministry of Environmental Protection of China, the DTPA extraction method is used to extract bioavailable Pb and Cd in the collected contaminated soil, 0.05 mol / L sodium bicarbonate is used to extract bioavailable As in the soil, and an inductively coupled plasma optical emission spectrometer (ICP-OES) is used to analyze the heavy metal content in the leaching solution.

[0040] The highly active heavy metal pollution remediation material and the ordinary remediation material prepared in this example were respectively added to the collected polluted soil at 2 wt% (recorded as dry powder, and the added mass of the remediation material was 2 wt% of the mass of the polluted soil). After mixing evenly, tap water was added to the soil for irrigation, and the added mass of tap water accounted for 30 wt% of the soil mass. Soil remediation was completed after 3 days. The changes in the contents of bioavailable heavy metals Pb, Cd, and As in the soil before remediation (CK group) and after remediation (including Example 1 and Comparative Example 1) are as Figure 1 shown. Before remediation (CK group), the contents of bioavailable Pb, Cd, and As in the soil were 531.03 mg / kg, 6.31 mg / kg, and 5.45 mg / kg, respectively. When the added mass of the remediation material was 2 wt% of the soil mass, the contents of bioavailable Pb, Cd, and As in the soil of the remediation group of Example 1 were reduced to 20.21 mg / kg, 2.59 mg / kg, and 0.77 mg / kg, respectively, and the passivation rates were 96.20%, 58.95%, and 85.87%, respectively, with obvious remediation effects. In the remediation group of Comparative Example 1, the contents of bioavailable Pb, Cd, and As in the soil were reduced to 494.99 mg / kg, 5.58 mg / kg, and 3.92 mg / kg, respectively, and the passivation rates were 6.79%, 11.57%, and 28.07%, respectively. It can be seen that the highly active heavy metal pollution remediation material prepared by the present invention has a significant remediation effect on heavy metals Pb, Cd, and As in the soil.

[0041] Example 2:

[0042] (1) Weigh 41.7 g of ferrous sulfate heptahydrate (FeSO4·7H2O), dissolve it in 500 mL of water to obtain an aqueous solution of ferrous sulfate, and place the aqueous solution of ferrous sulfate in a constant temperature water bath at 30 °C to heat it up to 30 °C.

[0043] (2) Disperse 133.38 g of calcium hydroxide in water, and then make up the volume to 300 mL to obtain a calcium hydroxide dispersion. Take 12.5 mL of the calcium hydroxide dispersion and add it dropwise to the aqueous solution of ferrous sulfate in step (1). After the addition is completed, stir and react in a constant temperature water bath at 30 °C for 1 h to obtain dispersion C.

[0044] (3) Dilute 1.025 g of glycerol with an equal mass of deionized water, stir evenly, and then add it dropwise to the above dispersion C. After the addition is completed, stir and react in a constant temperature water bath at 30 °C for 3 h. Then slowly add 25 mL of the calcium hydroxide dispersion prepared in step (2) to the obtained reaction mixture. After the addition is completed, continue to stir and react in a constant temperature water bath at 30 °C for 1 h to obtain dispersion D.

[0045] (4) Weigh 8 g of γ-aminopropyltriethoxysilane, disperse it into an equal mass of absolute ethanol. After uniform dispersion, add it dropwise to dispersion D. After the addition is complete, raise the temperature of the reaction system to 50 °C (the temperature can be raised using a water bath), and stir and react for 2 h. After the reaction is complete, transfer the obtained mixture to a centrifuge tube, centrifuge and separate at a speed of 4000 r / min for 10 min. Then pour off the supernatant, transfer the lower-layer solid to a vacuum drying oven, dry it at 90 °C until constant weight, and grind it to obtain a highly active heavy metal pollution remediation material.

[0046] Figure 2 It is the transmission electron microscope image of the highly active heavy metal pollution remediation material prepared in this example. It can be seen that the primary particle size of the material is 20 - 100 nm.

[0047] Add the highly active heavy metal pollution remediation material obtained in this example to the Pb(NO3)2 solution at a concentration of 3 g / L as the experimental group, and use the same-concentration Pb(NO3)2 solution without adding any remediation material as the blank control group. Shake and adsorb the experimental group and the blank control group at a rate of 200 r / min at 25 °C for 2 h. Then filter the obtained reaction mixture, and analyze the Pb content in the filtrates of the experimental group and the blank control group using an inductively coupled plasma optical emission spectrometer (ICP-OES). 2+ After adsorption by the highly active heavy metal pollution remediation material, the Pb in the solution 2+ decreased from 40.56 mg / L to 6.89 mg / L, and the removal effect of the heavy metal pollution remediation material on Pb 2+ reached 83.01%, indicating that the highly active heavy metal pollution remediation material prepared by the present invention can also significantly improve the removal rate of Pb in water. 2+

[0048] Example 3:

[0049] (1) Dissolve 64.88 g of ferric chloride in 500 mL of deionized water, stir until completely dissolved to obtain an aqueous ferric chloride solution, and place the aqueous ferric chloride solution in a constant temperature water bath at 60 °C to raise its temperature to 60 °C.

[0050] (2) Dissolve 112.2 g of KOH in water and make up the volume to 200 mL to obtain a KOH solution with a concentration of 10 mol / L. Gradually add 80 mL of the above KOH solution dropwise to the aqueous ferric chloride solution in step (1) while continuously stirring during the addition. After the addition is complete, stir and react in a constant temperature water bath at 60 °C for 36 min to obtain dispersion E.

[0051] (3) Add 1.74 g of sodium dodecylbenzenesulfonate to 5 g of deionized water. After stirring and dissolving, add it drop by drop to dispersion E. After the addition is complete, stir and react in a constant temperature water bath at 60 °C for 2 h. Subsequently, use a constant pressure dropping funnel to add 20 mL of the KOH solution prepared in step (2) to the resulting reaction mixture. After the addition is complete, continue to stir and react in a constant temperature water bath at 60 °C for 36 min to obtain dispersion F.

[0052] (4) Disperse 6.02 g of γ-mercaptopropyltrimethoxysilane in 6.02 g of deionized water and then add it drop by drop to dispersion F. Subsequently, heat the reaction system to 75 °C (the temperature can be raised using a water bath) and stir and react for 1 h. After the reaction is complete, perform vacuum filtration on the resulting mixture through a Buchner funnel and wash the filter cake with deionized water 2 - 3 times. Disperse the filter cake with water and transfer it to a spray dryer for spray drying to obtain a highly active heavy metal pollution remediation material.

[0053] Figure 3 and Figure 4 are the scanning electron microscope images of the highly active heavy metal pollution remediation material prepared in this example at magnifications of 500 times and 5000 times, respectively. It can be seen that the secondary particle size of the prepared highly active heavy metal pollution remediation material is about 10 - 50 μm, and it has a porous structure. There are a large number of pores on the material surface, and the pore distribution is relatively uniform. The rich pore structure is conducive to the migration of heavy metals to the adsorption material.

[0054] According to the Technical Specification for Soil Environmental Monitoring (HJ / T166 - 2004) issued by the Ministry of Environmental Protection of China, the DTPA extraction method was used to extract bioavailable Pb, Cd, and Cu in the collected contaminated soil, and 0.05 mol / L sodium bicarbonate was used to extract bioavailable As in the soil. An inductively coupled plasma optical emission spectrometer (ICP-OES) was used to analyze the heavy metal content in the leachate. The available contents of Pb, Cd, Cu, and As in the collected contaminated soil were 606 mg / kg, 7.65 mg / kg, 21.87, and 4.22 mg / kg, respectively. The highly active heavy metal contaminated soil remediation material prepared in this example was added to the collected contaminated soil at 1 wt% (recorded as dry powder, and the added mass of the remediation material was 1 wt% of the mass of the contaminated soil). After mixing evenly, tap water was added to the soil for irrigation, and the added mass of tap water accounted for 30 wt% of the soil mass. After 5 days of soil remediation, the available contents of Pb, Cd, Cu, and As in the soil were detected to be 256.38 mg / kg, 3.43 mg / kg, 5.56 mg / kg, and 2.52 mg / kg, respectively. The passivation rates of Pb, Cd, Cu, and As by the heavy metal contaminated soil remediation material prepared in this example were 57.69%, 55.16%, 74.58%, and 40.28%, respectively.

[0055] Example 4:

[0056] (1) Dissolve 80 g of ferric sulfate in 400 mL of deionized water, stir until completely dissolved to obtain an aqueous ferric sulfate solution, and place the aqueous ferric sulfate solution in a constant temperature water bath at 50 °C to heat it up to 50 °C.

[0057] (2) Take 7.5 mL of ammonia water with a mass fraction of 25% (concentration approximately 13.38 mol / L), and gradually add it dropwise to the aqueous ferric sulfate solution in step (1), continuously stirring during the dropping process. After the dropping is completed, stir and react in a constant temperature water bath at 50 °C for 25 min to obtain dispersion G.

[0058] (3) Add 2.4 g of sodium lauryl polyoxyethylene ether sulfate to 2.4 g of deionized water, heat and stir to dissolve it, and then gradually add it dropwise to the obtained dispersion G. After the dropping is completed, stir and react in a constant temperature water bath at 50 °C for 1.5 h. Subsequently, continue to gradually add 93 mL of the ammonia water described in step (2) dropwise to the obtained reaction mixture. After the dropping is completed, continue to stir and react in a constant temperature water bath at 50 °C for 1 h to obtain dispersion H.

[0059] (4) Uniformly disperse 4 g of ethylenediamine in 50 g of deionized water, and then add it dropwise to dispersion liquid H. Subsequently, heat the reaction system to 90 °C (the temperature can be raised using a water bath), and stir the reaction for 30 min. After the reaction is completed, filter the obtained mixture under reduced pressure through a Buchner funnel, and wash the filter cake with deionized water 2 - 3 times. The obtained filter cake is dried to constant weight in a vacuum drying oven at 70 °C, and then ground to obtain a high-activity heavy metal pollution remediation material.

[0060] Disperse 0.01 g of the high-activity heavy metal pollution remediation material prepared in this example in 10 g of deionized water. After ultrasonic dispersion, analyze the water dispersion particle size of the material using a laser particle size analyzer. The structure is as Figure 5 shown. It can be seen that the particle size distribution of the high-activity heavy metal pollution remediation material in water is relatively uniform, and its water dispersion particle size is in the range of 800 - 2000 nm.

[0061] The above are only examples of the present invention, and it is not limited to the present invention in any form. The present invention can also have other forms of embodiments based on the above structure and function, which will not be listed one by one. Therefore, any person skilled in the relevant art, without departing from the scope of the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a heavy metal pollution remediation material, characterized in that The following steps are involved: (1) dissolving an iron salt in water to prepare an iron salt aqueous solution, wherein the iron salt is ferrous sulfate or ferric sulfate or ferrous chloride or ferric chloride; (2) Add alkali solution dropwise to the iron salt aqueous solution of step (1) to make OH in the alkali solution added in step (2) - The molar number of Fe in the iron salt aqueous solution in step (1) 3+ or Fe 2+ The molar ratio of is 1:0.5~5. After the dropwise addition is completed, the mixture is reacted at 30~60°C for 0.15~1 h to obtain dispersion Ⅰ; (3) Add the interceptor to deionized water to dissolve it and then add it dropwise to the dispersion I obtained in step (2). After the addition is completed, react at 30-60°C for 1-3 hours; then continue to add alkali solution to the reaction mixture to ensure that the OH in the alkali solution added in step (2) and step (3) is - The total number of moles of Fe in the iron salt aqueous solution in step (1) 3+ or Fe 2+ The molar ratio of is 1:0.3~0.

5. After the dropwise addition is completed, the reaction is continued at 30~90℃ for 0.2~1h to obtain dispersion II; The interceptor is one or more of glycerol, fatty acid glyceride, sodium dodecylbenzene sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, and the mass of the interceptor added is 0.1-0.5% of the mass of dispersion I; (4) dissolving or dispersing the grafting agent in deionized water or anhydrous ethanol or ethanol aqueous solution, and then adding it dropwise into the dispersion II, reacting at 50-90° C. for 0.5-2 h. After the reaction is completed, performing solid-liquid separation on the obtained mixture, or performing drying after solid-liquid separation, to obtain the heavy metal pollution remediation material; The grafting agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, dithiocarbamate, and ethylenediamine, and the molar number of the grafting agent is the same as the Fe content in the iron salt aqueous solution of step (1). 3+ or Fe 2+ The molar ratio is 0.01~0.3:

1.

2. The method for preparing the heavy metal pollution remediation material according to claim 1, characterized in that The concentration of the iron salt aqueous solution in step (1) is 0.3-1.3 mol / L.

3. The method for preparing the heavy metal pollution remediation material according to claim 1 or 2, characterized in that The alkali solution described in step (2) and step (3) is sodium hydroxide solution, potassium hydroxide solution, ammonia solution or calcium hydroxide solution, the concentration of sodium hydroxide solution, potassium hydroxide solution and calcium hydroxide solution is 6-15 mol / L, and the mass percentage of ammonia solution is 18-25%.

4. The method for preparing the heavy metal pollution remediation material according to claim 1, characterized in that The ethanol aqueous solution described in step (4) is obtained by mixing anhydrous ethanol and deionized water, and the volume fraction of anhydrous ethanol in the ethanol aqueous solution is 10-90%.

5. The method for preparing the heavy metal pollution remediation material according to claim 1, characterized in that The solid-liquid separation in step (4) is carried out by filtration or centrifugal separation, and the drying is carried out by vacuum drying or spray drying.

6. The method for preparing the heavy metal pollution remediation material according to claim 1, characterized in that The primary particle size of the obtained heavy metal pollution remediation material is 20~200 nm, and the secondary particle size is 5~50 μm.

7. The use of the heavy metal pollution remediation material obtained by the preparation method as claimed in claim 1 in the treatment of heavy metal contaminated soil or heavy metal contaminated water. When it is used for the remediation of heavy metal contaminated soil, the added mass is 0.5~3% of the soil mass. When it is used for the treatment of heavy metal contaminated water, the added amount has a concentration of 0.1~5 g / L in the heavy metal contaminated water.

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