Preparation method and application of heavy metal pollution remediation material

Abstract

The invention relates to the technical field of soil or water heavy metal pollution remediation and treatment, in particular to a preparation method and application of a heavy metal pollution remediation material.The preparation method comprises the steps that alkali liquor is added into a ferric salt aqueous solution, and a reaction is conducted for 0.15-1 h at the temperature of 30-60 DEG C to obtain dispersion liquid I; adding a blocking agent solution into the dispersion liquid I, and reacting at 30-60 DEG C for 1-3 hours; then adding the alkali liquor again, and continuously reacting at 30-90 DEG C for 0.2-1 hour to obtain dispersion liquid II; and adding a grafting agent into the dispersion liquid II, reacting for 0.5-2 hours at 50-90 DEG C, and after the reaction is completed, carrying out solid-liquid separation on the obtained mixture, or carrying out drying treatment after solid-liquid separation to obtain the heavy metal pollution remediation material. According to the invention, the heavy metal pollution remediation material with controllable particle size and a high-activity reaction layer on the surface can be prepared through a simple preparation route by virtue of an interception-grafting technology, and the heavy metal pollution remediation material has a relatively high passivation rate on heavy metal ions and can be used for remediation and treatment of heavy metal polluted soil and heavy metal polluted water.

Description

Technical Field

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

[0002] With the development of industrial economy, the long-term accumulated heavy metal pollution in soil and water bodies has become increasingly prominent. Heavy metal pollution in soil and water bodies has a great impact on crops and food safety, and directly threatens human health. It is urgent to speed up the restoration of polluted soil and water bodies and realize the safe use of soil and water bodies.

[0003] Compared with heavy metal pollution in water bodies, heavy metal pollution in soil is more concealed, and due to the complexity of the soil environment, the removal of heavy metal pollutants is more difficult. At present, scholars have studied a variety of methods, such as soil import / soil replacement method, leaching method, electrical remediation method, passivation method, etc., but due to the limitations of many factors such as construction difficulty, remediation effect, and remediation cost, few remediation technologies have been widely used. Among the many methods, the in-situ passivation method has the advantages of simple construction and fast response speed for the remediation of heavy metal contaminated soil. It is a method that is more likely to be used on a large scale. The use of in-situ passivation remediation not only reduces the transport and accumulation of heavy metals in plants, but also plays a good stabilizing role in the structure of the soil. 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 composites and new nanomaterials that have emerged in recent years. Inorganic materials mainly include phosphorus-containing materials, lime materials, silicate materials, metals and their oxide materials. Organic materials mainly include crop straw, organic fertilizer, and biochar. Inorganic-organic composite materials are mainly composite materials composed of inorganic and organic passivation materials in a certain ratio. New nano passivation materials mainly include nanomaterials, mesoporous materials, functional membrane materials, and plant polyphenols. Common phosphorus-containing materials include phosphoric acid, calcium magnesium phosphate fertilizer, apatite, etc. Studies have shown that some phosphorus-containing materials have high background values ​​of heavy metals. Excessive application can easily increase the total amount and effective content of heavy metals in the soil, and the excessive presence of soluble phosphorus in the soil will lead to the loss of effective phosphorus, causing eutrophication of nearby water bodies. Common lime substances include lime, calcium hydroxide, calcium magnesium oxide, carbonate minerals, calcium magnesium carbonate minerals, dolomite, calcite, etc. The application of lime passivation materials has the most direct effect on the soil by increasing the soil pH value and producing a large amount of OH －, promoting the adsorption of heavy metals by soil colloids and clay particles, but excessive application of lime-based passivation materials will also have a negative impact on the soil quality, causing the organic matter in the soil to decompose too quickly, and easily forming a precipitation layer of calcium carbonate and calcium hydroxide cement under the topsoil layer, and even causing the soil to be over-limed, resulting in the concentration of heavy metal ions in the soil remaining high for a long time. Long-term application of lime will also destroy the soil aggregate structure, have a negative impact on the abundance of indigenous microorganisms and their community structure, easily lead to soil compaction and nutrient loss, and lead to 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 duration, which is not conducive to promotion and long-term use.

[0005] Solidification / stabilization remediation technology reduces the mobility of heavy metal ions by reacting between remediation materials and heavy metal ions, thereby achieving the solidification / stabilization of heavy metal ions in the soil. The core of 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. Studies have shown that iron oxides have multiple 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 passivation remediation of heavy metal contaminated soils, but the passivation efficiency of natural iron oxides or pure iron oxide materials is not enough to meet the performance requirements of current passivation materials, so artificial modification is often performed to improve its heavy metal passivation performance. China's invention patent application (application number 202210471194.8) discloses a nano-iron oxide composite material that can treat soil arsenic contamination. The material mainly includes nano-iron oxide loaded on biomass charcoal, nano-iron oxide loaded on citric acid, wollastonite or diatomaceous earth, and the reduction of arsenic can reach up to 70%. However, the preparation process of this repair agent is complicated and difficult to produce on a large scale. It is only effective against arsenic and is difficult to deal with the current widespread complex pollution. Summary of the invention

[0006] In view of the deficiencies in the above-mentioned prior arts and products, the present invention provides a method for preparing and applying a heavy metal pollution remediation material. Through the "interception-grafting" technology, a simple preparation route is adopted to prepare a heavy metal pollution remediation material with controllable particle size and a highly active reaction layer on the surface. The heavy metal pollution remediation material has a high passivation rate for heavy metals and can be used in the remediation and treatment of heavy metal contaminated soil and heavy metal contaminated water.

[0007] The present invention is specifically implemented by the following technical scheme. According to a preparation method of a heavy metal pollution repair material proposed by the present invention, the following steps are included: (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; (4) The grafting agent is dissolved or dispersed in deionized water or anhydrous ethanol or ethanol aqueous solution, and then added dropwise to the dispersion II, and reacted at 50-90° C. for 0.5-2 h. After the reaction is completed, the obtained mixture is subjected to solid-liquid separation, or solid-liquid separation and then drying to obtain the heavy metal pollution remediation material.

[0008] Preferably, the concentration of the aqueous solution of iron salt in step (1) is 0.3-1.3 mol / L.

[0009] Preferably, the alkali solution in step (2) and step (3) is a sodium hydroxide solution, a potassium hydroxide solution, an ammonia solution, or a calcium hydroxide solution, the concentration of the sodium hydroxide solution, the potassium hydroxide solution, and the calcium hydroxide solution is 6 to 15 mol / L, and the mass percentage of the ammonia solution is 18 to 25%.

[0010] Preferably, the interceptor is one or more of glycerol, fatty acid glyceride, sodium dodecylbenzene sulfonate, sodium polyoxyethylene fatty alcohol ether sulfate, and the mass of the interceptor added is 0.1-0.5% of the mass of the dispersion I.

[0011] Preferably, 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.

[0012] Preferably, the ethanol aqueous solution 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%.

[0013] Preferably, 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.

[0014] The primary particle size of the heavy metal pollution remediation material obtained by the above preparation method is 20~200 nm, and the secondary particle size is 5~50μm.

[0015] The present invention also provides a heavy metal pollution remediation material obtained according to the above-mentioned preparation method and its application 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 concentration of the added mass in the heavy metal contaminated water is 0.1-5 g / L.

[0016] Compared with the prior art, the present invention has obvious advantages and beneficial effects. By means of the above technical solution, the present invention can achieve considerable technical progress and practicality, and has a wide range of utilization value, and has at least the following advantages: (1) In the present invention, an interceptor is added after the iron salt and the alkali solution form iron hydroxide particles to prevent further dehydration and condensation between the iron hydroxide molecules and to prevent particle agglomeration. Then, the alkali solution is added again to promote the further generation 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 to promote the adsorption and passivation of heavy metals. The present invention uses the "interception-grafting" technology to adjust the amount and timing of the interceptor to prepare a heavy metal pollution remediation material with controllable particle size and a highly active reaction layer on the surface.

[0017] (2) The surface of the high-activity heavy metal pollution remediation material prepared by the present invention is evenly distributed with a large number of pores, which is conducive to the adsorption and fixation of heavy metal ions. The primary particle size of the material is 20~200 nm, 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 can achieve a higher remediation effect on heavy metals at a lower additive dosage. The high-activity heavy metal pollution remediation material prepared by the present invention can not only be used for the remediation of heavy metal contaminated soil, but also for the treatment of heavy metal contaminated water bodies. The high-activity heavy metal pollution remediation material has multiple effects in one dose and can simultaneously adsorb multiple heavy metal ions such as Pb, Cd, Cu, As, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a comparison chart of the changes in the contents of heavy metals Pb, Cd, and As in the soil extract before and after the remediation of contaminated soil using the highly active heavy metal pollution remediation material prepared in Example 1 and the common remediation material.

[0019] Figure 2 This is a transmission electron microscope image of the high-activity heavy metal pollution remediation material prepared in Example 2.

[0020] Figure 3 This is a scanning electron microscope image of the high-activity heavy metal pollution remediation material prepared in Example 3 at a magnification of 500 times.

[0021] Figure 4 This is a scanning electron microscope image of the high-activity heavy metal pollution remediation material prepared in Example 3 at a magnification of 5000 times.

[0022] Figure 5 This is the water-dispersed particle size distribution diagram of the high-activity heavy metal pollution remediation material prepared in Example 4. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The present invention is described in detail with specific examples below. If no specific conditions are specified in the following examples, they are all carried out according to conventional conditions or conditions recommended by the manufacturer. The raw materials and reagents used without indicating the manufacturer are all conventional products that can be purchased commercially. The heating method of the following examples can be heated by water bath, or by a magnetic stirrer, heating jacket or other device with heating function. The heating method described in the examples is not considered to be a limitation of the present invention.

[0025] Embodiment 1: (1) Weigh 77.5 g of ferrous chloride tetrahydrate (FeCl2·4H2O) and dissolve it in 300 mL of water to obtain an aqueous solution of ferrous chloride. Place the aqueous solution of ferrous chloride in a constant temperature water bath at 40°C to raise the temperature to 40°C.

[0026] (2) Dissolve 80 g of sodium hydroxide (NaOH) in a certain amount of water, and then adjust the volume to 200 mL to obtain a NaOH solution with a concentration of 10 mol / L; take 40 mL of the above NaOH solution and add it dropwise to the ferrous chloride aqueous solution in step (1). After the dropwise addition is completed, stir the reaction in a constant temperature water bath at 40°C for 10 min to obtain dispersion A.

[0027] (3) Weigh 1.5 g of fatty acid glyceride, evenly disperse it in 15 g of water, and then add it dropwise to dispersion A. After the addition is completed, stir the reaction in a constant temperature water bath at 40°C for 1 h. Then, continue to dropwise add 80 mL of the 10 mol / L NaOH solution prepared in step (2) to the resulting reaction mixture. After the addition is completed, continue to stir the reaction in a constant temperature water bath at 40°C for 0.5 h to obtain dispersion B.

[0028] (4) Weigh 12 g of sodium dimethyldithiocarbamate, dissolve it in 12 g of 50% ethanol aqueous solution, and then add it dropwise to dispersion B. Then heat the reaction system to 80 °C (it can be heated in a water bath), and stir the reaction for 2 h. After the reaction is completed, filter the resulting mixture, and the filter cake obtained is the highly active heavy metal pollution remediation material.

[0029] Comparative Example 1: Preparation of common restorative materials: (1) Weigh 77.5 g of ferrous chloride tetrahydrate (FeCl2·4H2O) and dissolve it in 300 mL of water to obtain an aqueous solution of ferrous chloride. Place the aqueous solution of ferrous chloride in a constant temperature water bath at 40°C to raise the temperature to 40°C.

[0030] (2) Dissolve 80 g of sodium hydroxide (NaOH) in water and adjust the volume to 200 mL to obtain a NaOH solution with a concentration of 10 mol / L; take 120 mL of the above NaOH solution and add it dropwise to the ferrous chloride aqueous solution in step (1). After the addition is completed, stir and react in a constant temperature water bath at 40°C for 20 min. After the reaction is completed, filter the obtained dispersion to obtain a filter cake as a common repair material.

[0031] According to the Technical Specifications for Soil Environmental Monitoring (HJ / T166-2004) issued by the Ministry of Environmental Protection of China, the DTPA extraction method was used to extract the biologically effective Pb and Cd in the collected contaminated soil, 0.05 mol / L sodium bicarbonate was used to extract the biologically effective As in the soil, and the heavy metal content in the extract was analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES).

[0032] The highly active heavy metal pollution remediation material prepared in this example and the common remediation material were added to the collected contaminated soil at 2 wt% (in terms of dry powder, the added mass of the remediation material was 2 wt% of the mass of the contaminated soil), mixed evenly, and then tap water was added to the soil for irrigation. The added mass of tap water accounted for 30 wt% of the mass of the soil. The soil remediation was completed after 3 days. The changes in the content of biologically effective heavy metals Pb, Cd, and As in the soil before remediation (CK group) and after remediation (including Example 1 and Comparative Example 1) are shown in Figure 1. Figure 1 As shown. Before remediation (CK group), the contents of biologically effective 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 biologically effective 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, and the remediation effect was obvious. In the soil of the remediation group of Comparative Example 1, the contents of biologically effective Pb, Cd, and As 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 high-activity 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.

[0033] Embodiment 2: (1) Weigh 41.7 g of ferrous sulfate heptahydrate (FeSO4·7H2O) and dissolve it in 500 mL of water to obtain an aqueous solution of ferrous sulfate. Place the aqueous solution of ferrous sulfate in a constant temperature water bath at 30°C to raise the temperature to 30°C.

[0034] (2) Disperse 133.38 g of calcium hydroxide in water, and then adjust 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 ferrous sulfate aqueous solution in step (1). After the addition is completed, stir the reaction in a constant temperature water bath at 30°C for 1 h to obtain a dispersion C.

[0035] (3) Dilute 1.025 g of glycerol with an equal mass of deionized water, stir evenly, and then add dropwise to the above dispersion C. After the addition is complete, stir and react in a 30°C constant temperature water bath 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 complete, continue to stir and react in a 30°C constant temperature water bath for 1 h to obtain dispersion D.

[0036] (4) Weigh 8 g of γ-aminopropyltriethoxysilane and disperse it in an equal amount of anhydrous ethanol. After uniform dispersion, add it dropwise to dispersion D. After the addition is completed, heat the reaction system to 50 °C (it can be heated in a water bath) and stir for 2 h. After the reaction is completed, transfer the resulting mixture to a centrifuge tube and centrifuge it at 4000 r / min for 10 min. Then pour off the supernatant and transfer the lower solid to a vacuum drying oven. Dry it at 90 °C to constant weight and grind it to obtain a highly active heavy metal pollution remediation material.

[0037] Figure 2 This is a 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 between 20 and 100 nm.

[0038] The highly active heavy metal pollution remediation material obtained in this example was added to the Pb(NO3)2 solution at a concentration of 3 g / L as the experimental group, and the Pb(NO3)2 solution with the same concentration without any remediation material was used as the blank control group. The experimental group and the blank control group were subjected to oscillation adsorption at a rate of 200 r / min at 25°C for 2 h, and then the obtained reaction mixture was filtered. The Pb in the filtrate of the experimental group and the blank control group was measured by inductively coupled plasma optical emission spectrometry (ICP-OES). 2+ After being adsorbed by highly active heavy metal pollution remediation materials, the Pb 2+ From 40.56 mg / L to 6.89 mg / L, the heavy metal pollution remediation material has a significant impact on Pb 2+ The removal effect of Pb in water was 83.01%, indicating that the high-activity heavy metal pollution remediation material prepared by the present invention can also significantly improve the removal of Pb in water. 2+ removal rate.

[0039] Embodiment 3: (1) Dissolve 64.88 g of ferric chloride in 500 mL of deionized water and stir until completely dissolved to obtain an aqueous solution of ferric chloride. Place the aqueous solution of ferric chloride in a constant temperature water bath at 60°C to raise the temperature to 60°C.

[0040] (2) Dissolve 112.2 g of KOH in water and adjust the volume to 200 mL to obtain a KOH solution with a concentration of 10 mol / L. Add 80 mL of the above KOH solution dropwise to the ferric chloride aqueous solution in step (1) through a constant pressure dropping funnel, stirring continuously during the addition process. After the addition is completed, stir the reaction in a constant temperature water bath at 60°C for 36 min to obtain dispersion E.

[0041] (3) Add 1.74 g of sodium dodecylbenzene sulfonate to 5 g of deionized water, stir to dissolve, and then dropwise add to dispersion E. After the addition is completed, stir and react in a constant temperature water bath at 60°C for 2 h. Then, add 20 mL of the KOH solution prepared in step (2) to the resulting reaction mixture using a constant pressure dropping funnel. After the addition is completed, continue to stir and react in a constant temperature water bath at 60°C for 36 min to obtain dispersion F.

[0042] (4) Disperse 6.02 g of γ-mercaptopropyltrimethoxysilane in 6.02 g of deionized water and then add the mixture dropwise to dispersion F. Then, heat the reaction system to 75 °C (the temperature can be raised in a water bath) and stir for 1 h. After the reaction is completed, filter the resulting mixture through a Buchner funnel under reduced pressure, and wash the filter cake with deionized water for 2 to 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.

[0043] Figure 3 and Figure 4 The scanning electron microscope images of the high-activity heavy metal pollution remediation material prepared in this embodiment at magnifications of 500 times and 5000 times respectively show that the secondary particle size of the prepared high-activity heavy metal pollution remediation material is about 10~50 μm, it has a porous structure, there are a large number of pores on the surface of the material, the pore distribution is relatively uniform, and the rich pore structure is conducive to the migration of heavy metals to the adsorption material.

[0044] According to the Technical Specifications for Soil Environmental Monitoring (HJ / T166-2004) issued by the Ministry of Environmental Protection of China, the DTPA extraction method was used to extract the biologically effective Pb, Cd, and Cu in the collected contaminated soil, 0.05 mol / L sodium bicarbonate was used to extract the biologically effective As in the soil, and the heavy metal content in the extract was analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). The effective 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 high-activity heavy metal pollution remediation material prepared in this embodiment was added to the collected contaminated soil at 1 wt% (in terms of dry powder, 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. The added mass of tap water accounted for 30 wt% of the soil mass. After 5 days of soil remediation, the effective 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 the heavy metal pollution remediation material prepared in this embodiment for Pb, Cd, Cu and As were 57.69%, 55.16%, 74.58% and 40.28%, respectively.

[0045] Embodiment 4: (1) Dissolve 80 g of ferric sulfate in 400 mL of deionized water and stir until completely dissolved to obtain an aqueous solution of ferric sulfate. Place the aqueous solution of ferric sulfate in a constant temperature water bath at 50 °C and heat it to 50 °C.

[0046] (2) Take 7.5 mL of 25% ammonia solution (concentration of about 13.38 mol / L) and add it dropwise to the ferric sulfate solution in step (1), stirring continuously during the addition. After the addition is completed, stir the reaction in a constant temperature water bath at 50°C for 25 min to obtain dispersion G.

[0047] (3) Add 2.4 g of sodium fatty alcohol polyoxyethylene ether sulfate to 2.4 g of deionized water, heat and stir to dissolve it, and then add it dropwise to the obtained dispersion G. After the addition is completed, stir and react in a 50°C constant temperature water bath for 1.5 h. Then, continue to add 93 mL of the ammonia solution described in step (2) dropwise to the obtained reaction mixture. After the addition is completed, continue to stir and react in a 50°C constant temperature water bath for 1 h to obtain dispersion H.

[0048] (4) Disperse 4 g of ethylenediamine evenly in 50 g of deionized water, and then add dropwise to the dispersion H. Then, heat the reaction system to 90 °C (can be heated in a water bath), and stir the reaction for 30 min. After the reaction is completed, filter the resulting mixture through a Buchner funnel under reduced pressure, and wash the filter cake with deionized water 2 to 3 times. The resulting filter cake is dried in a vacuum oven at 70 °C to constant weight, and then ground to obtain a highly active heavy metal pollution remediation material.

[0049] 0.01 g of the highly active heavy metal pollution remediation material prepared in this example was dispersed in 10 g of deionized water. After ultrasonic dispersion, the water-dispersed particle size of the material was analyzed using a laser particle size analyzer. The structure is as follows: Figure 5 It can be seen that the particle size distribution of the highly active heavy metal pollution remediation material in water is relatively uniform, and its water-dispersible particle size is 800~2000 nm.

[0050] The above is only an embodiment of the present invention, and does not limit the present invention in any form. The present invention can also have other forms of embodiments according to the above structures and functions, which are not listed one by one. Therefore, any simple modification, equivalent change and modification made by any technician familiar with the profession to the above embodiment according to the technical essence of the present invention without departing from the scope of the technical solution of the present invention still falls 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; (4) The grafting agent is dissolved or dispersed in deionized water or anhydrous ethanol or ethanol aqueous solution, and then added dropwise to the dispersion II, and reacted at 50-90° C. for 0.5-2 h. After the reaction is completed, the obtained mixture is subjected to solid-liquid separation, or solid-liquid separation and then drying to obtain the heavy metal pollution remediation material.

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 interceptor is one or more of glycerol, fatty acid glyceride, sodium dodecylbenzene sulfonate, sodium polyoxyethylene fatty alcohol ether sulfate, and the mass of the interceptor added is 0.1-0.5% of the mass of the dispersion I.

5. The method for preparing the heavy metal pollution remediation material according to claim 1 or 4, characterized in that 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.

6. 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%.

7. 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.

8. 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.

9. 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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