Arsenic-antimony contaminated soil remediation agent, preparation method and application thereof

Abstract

The application relates to an arsenic-antimony contaminated soil remediation agent and a preparation method and application thereof, and the method comprises the following steps: performing first pyrolysis treatment on clay minerals to obtain a first pyrolysis product; and mixing the first pyrolysis product and a hydrohonessite type manganese dioxide, and performing second pyrolysis treatment on the mixture under the action of an organic acid to obtain a second pyrolysis product. The arsenic-antimony contaminated soil remediation agent obtained by the above method has long-term and stable remediation effect on arsenic single contaminated soil, antimony single contaminated soil or arsenic-antimony composite contaminated soil.

Description

Technical Field

[0001] This application relates to the fields of soil remediation and environmental functional materials technology, and in particular to an arsenic-antimony contaminated soil remediation agent, its preparation method and application. Background Technology

[0002] Currently, inorganic soil pollution, particularly heavy metals, presents a severe situation. Stabilization is the most commonly used remediation technology for heavy metal pollution in soil, with an adoption rate as high as 48.5% in 2018. However, traditional stabilization materials fail in practical applications due to factors such as fissure development and acid leaching. Furthermore, compared to positively charged cationic heavy metals (such as cadmium, lead, and copper), arsenic and antimony exist in soil as oxyanions, exhibiting the same electrical properties as soil colloids and exhibiting stronger mobility than cationic heavy metals, making stabilization more difficult.

[0003] Therefore, it is necessary to provide a stable soil remediation material that can achieve long-term remediation for arsenic and antimony pollution. Summary of the Invention

[0004] Based on this, the present invention provides an arsenic-antimony contaminated soil remediation agent, its preparation method and application, which can achieve long-term and stable remediation of arsenic-antimony combined contaminated soil.

[0005] The first aspect of this application provides a method for preparing an arsenic-antimony contaminated soil remediation agent, comprising the following steps:

[0006] The clay minerals were subjected to a first pyrolysis treatment to obtain the first pyrolysis product; and

[0007] The first pyrolysis product was mixed with manganese dioxide of the sodium manganese ore type, and the mixture was subjected to a second pyrolysis treatment under the action of organic acid to obtain the second pyrolysis product.

[0008] In some embodiments, the clay minerals include kaolin and sepiolite, and optionally, the mass ratio of the kaolin to the sepiolite is 1:(2~4).

[0009] In some embodiments, the mass ratio of the first pyrolysis product to the sodium manganese dioxide is (6~8):1.

[0010] In some embodiments, the temperature of the first pyrolysis treatment is 400°C to 500°C, and the duration of the first pyrolysis treatment is 2 hours to 3 hours.

[0011] In some embodiments, the temperature of the second pyrolysis treatment is 600°C to 800°C, and the temperature of the second pyrolysis treatment is 4h to 6h.

[0012] In some embodiments, the method of subjecting the mixture to a second pyrolysis treatment in the presence of an aqueous solution of an organic acid includes the step of immersing the mixture of the first pyrolysis product and the sodium manganese dioxide in the aqueous solution of the organic acid.

[0013] In some embodiments, the concentration of the organic acid in the aqueous solution is 0.1 mol / L to 0.5 mol / L, and the soaking time is 1 to 3 hours.

[0014] In some embodiments, the organic acid includes one or more of citric acid, malic acid, oxalic acid, and tartaric acid, with citric acid being an option.

[0015] In some embodiments, the step of acid washing of the clay minerals is included before the first pyrolysis treatment of the clay minerals.

[0016] In some embodiments, the acid solution used in the pickling step contains H... + The concentration of the acid is 1 mol / L to 5 mol / L, the solid-liquid ratio of the clay mineral and the acid solution is 1:(5~20), the unit is g / mL, and the reaction time of the acid solution is 1h to 3h.

[0017] In a second aspect, this application provides an arsenic-antimony contaminated soil remediation agent prepared by the method of the first aspect of this application.

[0018] In a third aspect of this application, the application of the arsenic-antimony contaminated soil remediation agent described in the second aspect of this application is provided for soil remediation.

[0019] In some embodiments, the soil is arsenic-contaminated soil, antimony-contaminated soil, or arsenic-antimony contaminated soil.

[0020] In a fourth aspect, this application provides a soil remediation method, comprising adding an arsenic-antimony contaminated soil remediation agent of the second aspect of this application to the soil to be remediated, wherein the amount of the arsenic-antimony contaminated soil remediation agent added is 1% to 5% of the mass of the soil to be remediated.

[0021] In some embodiments, the soil remediation method further includes adding the arsenic-antimony contaminated soil remediation agent and then watering the soil to be remediated for 5 to 7 days, with the amount of water being 25% to 40% of the mass of the soil to be remediated.

[0022] Compared with the prior art, this application has at least the following beneficial effects:

[0023] The method for preparing the arsenic-antimony contaminated soil remediation agent provided in this application involves modifying clay minerals with manganese dioxide of the sodium manganese oxide type, followed by two pyrolysis treatments to obtain the arsenic-antimony contaminated soil remediation agent. The arsenic-antimony contaminated soil remediation agent obtained by this method exhibits long-term and stable remediation effects on arsenic-contaminated soil, antimony-contaminated soil, or soil with combined arsenic-antimony contamination. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the preparation method of the arsenic-antimony contaminated soil remediation agent according to one embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the preparation method of an arsenic-antimony contaminated soil remediation agent according to another embodiment of this application. Detailed Implementation

[0027] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0028] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0029] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0030] In this application, "one or more" means any one, two or more of the listed items.

[0031] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0032] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0033] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0034] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0035] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0036] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0037] Please see Figure 1 According to a first aspect of this application, a method for preparing an arsenic-antimony contaminated soil remediation agent is provided, comprising the following steps:

[0038] S10, the clay minerals are subjected to a first pyrolysis treatment to obtain the first pyrolysis product; and

[0039] S20, the first pyrolysis product is mixed with manganese dioxide of sodium manganese ore type, and the mixture is subjected to a second pyrolysis treatment under the action of organic acid to obtain the second pyrolysis product.

[0040] The above-mentioned method for preparing arsenic-antimony contaminated soil remediation agent involves modifying clay minerals with manganese dioxide of the sodium manganese oxide type, combined with two pyrolysis treatments to obtain the remediation agent. By modifying the clay minerals with manganese dioxide of the sodium manganese oxide type, the remediation agent possesses both physical and chemical adsorption properties. Furthermore, the first pyrolysis treatment removes adsorbed water from the interlayer of the clay minerals, and the second pyrolysis treatment achieves lattice transformation under the action of organic acids. Without being limited to any specific theory, the arsenic-antimony contaminated soil remediation agent obtained by this preparation method exhibits long-term and stable remediation effects on soils contaminated with arsenic alone, antimony alone, or a combination of arsenic and antimony.

[0041] Clay minerals can be a single component or a combination of multiple components. Multiple-component clay minerals are also called compound clay minerals, where the components work synergistically. In some embodiments, the clay minerals include kaolin and sepiolite. Optionally, in some embodiments, the mass ratio of kaolin to sepiolite is 1:(2~4), such as 1:2.5, 1:3, 1:3.5, and any ratio between them. A mass ratio of kaolin to sepiolite within this range is more beneficial to the adsorption and stability of the soil remediation agent. If the mass proportion of kaolin is too high, the total number of surface adsorption sites in the arsenic-antimony contaminated soil remediation agent will decrease; if the mass proportion of sepiolite is too high, the arsenic-antimony contaminated soil remediation agent will have too good ductility after addition, making it prone to instability and lattice instability.

[0042] The mesh size of a single component or each component in a clay mineral can be selected from 80 to 120 mesh, such as 85 mesh, 90 mesh, 95 mesh, 100 mesh, 105 mesh, 110 mesh, 115 mesh, and any value between them.

[0043] In some embodiments, the temperature of the first pyrolysis treatment is 400°C to 500°C, such as 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, and any value between them. Temperatures within this range are more conducive to the long-term stability of the arsenic-antimony contaminated soil remediation agent. If the temperature of the first pyrolysis treatment is too low, the interlayer adsorbed water of the clay minerals cannot be completely removed, and the adsorption capacity of the arsenic-antimony contaminated soil remediation agent cannot be effectively activated; if the temperature of the first pyrolysis treatment is too high, the crystal lattice will undergo thermal destabilization.

[0044] In some implementations, the first pyrolysis treatment time is 2h to 3h, for example 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h, and any value between them.

[0045] In some embodiments, the temperature of the second pyrolysis treatment is 600°C to 800°C, for example 620°C, 640°C, 660°C, 680°C, 700°C, 720°C, 740°C, 760°C, 780°C, and any value between them. Temperatures within this range are more conducive to the recombination of clay minerals and naphthoic minerals to form new crystal lattices.

[0046] In some implementations, the second pyrolysis treatment time is 4h to 6h, for example 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h and any value between them.

[0047] In some embodiments, the mass ratio of the first pyrolysis product to manganese dioxide of the hydrated manganese oxide type is (6~8):1, for example 6:1, 6.5:1, 7:1, 7.5:1, and any value between them. Clay minerals primarily play a physical adsorption role, while the role of hydrated manganese oxide type manganese dioxide is to modify the clay minerals to also possess chemical adsorption capabilities. Therefore, within this range, the ratio of the two has a better adsorption and remediation effect on arsenic and antimony in contaminated soil.

[0048] It should be noted that both the first and second pyrolysis treatments are carried out under an inert atmosphere, such as nitrogen.

[0049] The second pyrolysis treatment mentioned above requires the mixture to be carried out under the action of organic acids. That is, during the second pyrolysis treatment, organic acids are present in the mixture of the first pyrolysis product and naphthoic manganese dioxide. The organic acids provide an acidic environment for the second pyrolysis, which is conducive to high-temperature pyrolysis and reorganization, allowing the clay minerals and naphthoic manganese dioxide to form new crystal lattices.

[0050] In some embodiments, the method of subjecting the mixture to a second pyrolysis treatment under the action of organic acid includes immersing the mixture of the first pyrolysis product and manganese dioxide of the sodium manganese hydrate type in an aqueous solution of organic acid. It should be further noted that the immersed mixture is not rinsed, and the second pyrolysis treatment is carried out in the presence of organic acid in the mixture of the first pyrolysis product and manganese dioxide of the sodium manganese hydrate type. In other embodiments, the immersed mixture is not dried. Drying would reduce the stabilizing and remediating effect of the soil remediation agent.

[0051] The aqueous solution of the organic acid primarily provides an acidic environment for the second pyrolysis process, which is beneficial for the high-temperature pyrolytic remodeling and recombination during the second pyrolysis, allowing clay minerals and manganese dioxide of the hydrated manganese oxide type to recombine and form new crystal lattices. In some embodiments, the concentration of the organic acid in the aqueous solution is 0.1 mol / L to 0.5 mol / L. Optionally, the organic acid includes one or more of citric acid, malic acid, oxalic acid, and tartaric acid. More preferably, the organic acid is citric acid.

[0052] In some embodiments, the mixture of the first pyrolysis product and the hydrated manganese dioxide is immersed in an aqueous solution of organic acid for 1 to 3 hours.

[0053] Please see Figure 2 In some embodiments, step S10, before the first pyrolysis treatment of the clay minerals, further includes step S00: acid washing of the clay minerals. The purpose of acid washing is to remove impurities from the clay minerals.

[0054] In some embodiments, the acid solution used in the pickling step contains H + The concentration is 1 mol / L to 5 mol / L, for example, it can also be 2 mol / L, 3 mol / L, or 4 mol / L. The acid used in the pickling step may include one or more of hydrochloric acid, sulfuric acid, or nitric acid.

[0055] In some embodiments, the solid-liquid ratio of clay minerals and acid is 1:(5~20) (g / mL), for example, it can also be 1:6 (g / mL), 1:8 (g / mL), 1:10 (g / mL), 1:12 (g / mL), 1:14 (g / mL), 1:16 (g / mL), or 1:18 (g / mL).

[0056] In some embodiments, the acid solution is applied for 1 to 3 hours, for example, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, or 2.8 hours.

[0057] A second aspect of this application provides an arsenic-antimony contaminated soil remediation agent prepared by the method of the first aspect of this application.

[0058] A third aspect of this application provides the application of the arsenic-antimony contaminated soil remediation agent of the second aspect of this application in soil remediation. In some embodiments, the soil is arsenic-contaminated soil, antimony-contaminated soil, or arsenic-antimony combined contaminated soil.

[0059] A fourth aspect of the embodiments of this application provides a soil remediation method, comprising adding an arsenic-antimony contaminated soil remediation agent of the second aspect of this application to the soil to be remediated, wherein the amount of the arsenic-antimony contaminated soil remediation agent added is 1% to 5% of the mass of the soil to be remediated.

[0060] In some embodiments, the above-mentioned soil remediation method further includes adding water to the soil to be remediated after adding the arsenic-antimony contaminated soil remediation agent, the curing time being 5 to 7 days, and the amount of water added being 25% to 40% of the mass of the soil to be remediated.

[0061] The following are specific embodiments. They are intended to provide a more detailed description of this application to help those skilled in the art and researchers better understand it. The technical conditions described do not constitute any limitation on this application. Any modifications made within the scope of the claims of this application are protected by the claims.

[0062] Unless otherwise stated, all raw materials and reagents used in the following examples are commercially available or can be prepared by known methods. All instruments are conventionally selected in the art. Experimental methods not specifically described in the examples were performed under conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0063] Preparation Example 1

[0064] 1. Mix kaolin (100 mesh) and sepiolite (100 mesh) at a mass ratio of 1:2, soak in 2 mol / L hydrochloric acid for 1 hour (solid-liquid ratio 1:10 g / mL), and then rinse with deionized water until the pH of the eluent does not change, to obtain compound clay mineral powder.

[0065] 2. The compound clay mineral powder was subjected to a first pyrolysis by placing it in a muffle furnace at 500°C under a nitrogen atmosphere for 2 hours to obtain the first pyrolysis product.

[0066] 3. The first pyrolysis product and manganese dioxide of sodium manganese ore type (100 mesh) were mixed at a mass ratio of 8:1, ball-milled at 300 rpm for 1 h, and then soaked in 0.2 mol / L citric acid for 2 h. The moistened soaked material was then subjected to a second pyrolysis, which was carried out in a muffle furnace at 700℃ under a nitrogen atmosphere for 5 h.

[0067] Preparation Example 2

[0068] The preparation method of Preparation Example 2 is basically the same as that of Preparation Example 1, except that the mass ratio of kaolin and sepiolite is replaced with 1:1.

[0069] Preparation Example 3

[0070] The preparation method of Preparation Example 3 is basically the same as that of Preparation Example 1, except that the mass ratio of kaolin and sepiolite is replaced with 1:4.

[0071] Preparation Example 4

[0072] The preparation method of Preparation Example 4 is basically the same as that of Preparation Example 1, except that the mass ratio of kaolin and sepiolite is replaced with 1:5.

[0073] Preparation Example 5

[0074] The preparation method of Preparation Example 5 is basically the same as that of Preparation Example 1, except that the temperature of the first pyrolysis of the compound clay mineral powder in the muffle furnace in step 2 is replaced with 300℃.

[0075] Preparation Example 6

[0076] The preparation method of Preparation Example 6 is basically the same as that of Preparation Example 1, except that the temperature of the first pyrolysis of the compound clay mineral powder in the muffle furnace in step 2 is replaced with 400℃.

[0077] Preparation Example 7

[0078] The preparation method of Preparation Example 7 is basically the same as that of Preparation Example 1, except that the temperature of the first pyrolysis of the compound clay mineral powder in the muffle furnace in step 2 is replaced with 600℃.

[0079] Preparation Example 8

[0080] The preparation method of Preparation Example 8 is basically the same as that of Preparation Example 1, except that the temperature of the second pyrolysis is replaced with 600℃.

[0081] Preparation Example 9

[0082] The preparation method of Preparation Example 9 is basically the same as that of Preparation Example 1, except that the temperature of the second pyrolysis is replaced with 800℃.

[0083] Preparation Example 10

[0084] The preparation method of Preparation Example 10 is basically the same as that of Preparation Example 1, except that the temperature of the second pyrolysis is replaced with 500℃.

[0085] Preparation Example 11

[0086] The preparation method of Preparation Example 11 is basically the same as that of Preparation Example 1, except that the temperature of the second pyrolysis is replaced with 900℃.

[0087] Preparation Example 12

[0088] The preparation method of Preparation Example 12 is basically the same as that of Preparation Example 1, except that the mass ratio of the first pyrolysis product to sodium manganese dioxide is replaced with 5:1.

[0089] Preparation Example 13

[0090] The preparation method of Preparation Example 13 is basically the same as that of Preparation Example 1, except that the mass ratio of the first pyrolysis product to sodium manganese dioxide is replaced with 9:1.

[0091] Preparation Example 14

[0092] The preparation method of Preparation Example 14 is basically the same as that of Preparation Example 1, except that the mass ratio of the first pyrolysis product to sodium manganese dioxide is replaced with 6:1.

[0093] Preparation Example 15

[0094] The preparation method of Preparation Example 15 is basically the same as that of Preparation Example 1, except that the mass ratio of the first pyrolysis product to sodium manganese dioxide is replaced with 7:1.

[0095] Preparation Example 16

[0096] The preparation method of Preparation Example 16 is basically the same as that of Preparation Example 1, except that in step 3, the moistened soaked material is dried before the second pyrolysis.

[0097] Preparation Example 17

[0098] The preparation method of Preparation Example 16 is basically the same as that of Preparation Example 1, except that the acid washing treatment in step 1 is omitted and the mixture of kaolin and sepiolite is directly subjected to the first pyrolysis treatment.

[0099] Preparation of Comparative Example 1

[0100] The preparation method of Comparative Example 1 is basically the same as that of Preparation Example 1, except that the citric acid soaking step is omitted and the mixture of the first pyrolysis product and the water-sodium manganese dioxide ball milling mixture is directly subjected to a second pyrolysis.

[0101] Preparation of Comparative Example 2

[0102] The preparation method of Comparative Example 2 is basically the same as that of Preparation Example 1, except that: no modification is made to the clay minerals, and only the compound clay minerals are acid washed, that is, only step 1 in Preparation Example 1 is performed.

[0103] Example 1

[0104] Soil from a non-ferrous metal mining and beneficiation site in southwestern my country was selected as the target soil for remediation. A soil remediation agent was applied to the soil for stabilization treatment. The soil at this site was contaminated with arsenic and antimony, with arsenic concentrations of 294.5 ± 15.3 mg / kg and antimony concentrations of 449.2 ± 37.5 mg / kg. The soil particle size was less than 2 mm. The soil remediation agent prepared in Example 1 was added to the soil at a mass ratio of 3% (the percentage of soil remediation agent to dry soil mass), and water was added at 30% (the percentage of water added to dry soil mass) for 7 days.

[0105] Examples 2-15

[0106] Examples 2-15 are basically similar to Example 1, except that the soil remediation agent prepared in Example 1 is replaced with the soil remediation agent prepared in Examples 2-15.

[0107] Comparative Examples 1-2

[0108] Comparative Examples 1 and 2 are basically similar to Example 1, except that the soil remediation agent prepared in Example 1 is replaced with the soil remediation agent prepared in Comparative Examples 1 and 2.

[0109] Comparative Examples 3-5

[0110] Comparative Examples 3-5 are basically similar to Example 1, except that the soil remediation agent prepared in Example 1 is replaced with kaolin, sepiolite, and sodium manganese dioxide, respectively.

[0111] The process parameters used in the preparation methods of Examples 1-15 are listed in Table 1 below:

[0112] Table 1

[0113]

[0114] The soils remediated in Examples 1-15 and Comparative Examples 1-5 were tested for short-term and long-term remediation effects. The specific testing methods are as follows:

[0115] 1. Short-term repair effect testing method

[0116] Heavy metals in soil were leached using a horizontal oscillation method, and the arsenic leaching concentrations C0 and C2 before and after stabilization were measured using inductively coupled plasma mass spectrometry (ICP-MS). t1 Antimony leaching concentrations C'0 and C' before and after stabilization t1 Calculate the short-term repair stabilization rate η1 = (C0 - C t1) / C0*100%, Short-term repair Sb stabilization rate η2=(C'0-C') t1 ) / C'0*100%.

[0117] 2. Long-term repair effect testing method

[0118] The stabilized soil was subjected to 20 aging treatments. Using the same methods or standards as for short-term remediation effectiveness testing, the arsenic leaching concentration C before and after aging was measured. t1 and C t2 Antimony leaching concentration C' before and after aging t1 and C' t2 Calculate the long-term repair As stabilization rate η3 = (C t1 -C t2 ) / C t1 *100%, Short-term repair Sb stabilization rate η4=(C' t1 -C' t2 ) / C' t1 *100%.

[0119] The test results are shown in Table 2:

[0120] Table 2

[0121]

[0122] Therefore, it is evident that the soil remediation agent prepared by the method provided in this application for remediating arsenic-antimony contaminated soil exhibits a longer-lasting and stable remediation effect. It should be noted that although the short-term remediation stabilization rates η1 and η2 in Comparative Example 1 are relatively high, the long-term remediation stabilization rates η3 and η4 are very low, indicating that the remediation agent prepared without the action of organic acids has poor long-term stability.

[0123] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing an arsenic-antimony contaminated soil remediation agent, characterized in that, Includes the following steps: The clay minerals were subjected to a first pyrolysis treatment to obtain the first pyrolysis product; as well as The first pyrolysis product was mixed with manganese dioxide of sodium manganese ore type, and the mixture was subjected to a second pyrolysis treatment under the action of organic acid to obtain the second pyrolysis product. A method for subjecting the mixture to a second pyrolysis treatment under the action of an organic acid includes: immersing the mixture of the first pyrolysis product and the sodium manganese dioxide in an aqueous solution of the organic acid; The organic acid is citric acid; The clay minerals are kaolin and sepiolite; the mass ratio of kaolin to sepiolite is 1:(2~4). The mass ratio of the first pyrolysis product to the sodium manganese dioxide of the hydrated manganese oxide type is (6~8):1; The temperature of the first pyrolysis treatment is 400℃~500℃, and the time of the first pyrolysis treatment is 2h~3h; The temperature of the second pyrolysis treatment is 600℃~800℃, and the time of the second pyrolysis treatment is 4h~6h; Both the first and second pyrolysis treatments were carried out under an inert atmosphere.

2. The preparation method of the arsenic-antimony contaminated soil remediation agent according to claim 1, characterized in that, The concentration of the organic acid in the aqueous solution is 0.1 mol / L to 0.5 mol / L, and the soaking time is 1 to 3 hours.

3. The preparation method of the arsenic-antimony contaminated soil remediation agent according to claim 1 or 2, characterized in that, Before the first pyrolysis treatment of the clay minerals, the method further includes an acid washing step of the clay minerals.

4. The preparation method of the arsenic-antimony contaminated soil remediation agent according to claim 3, characterized in that, The acid solution used in the pickling step contains H... + The concentration of the acid is 1 mol / L to 5 mol / L, the solid-liquid ratio of the clay mineral and the acid solution is 1:(5~20), the unit is g / mL, and the reaction time of the acid solution is 1h to 3h.

5. The arsenic-antimony contaminated soil remediation agent prepared by the method according to any one of claims 1 to 4.

6. The application of the arsenic-antimony contaminated soil remediation agent as described in claim 5 in soil remediation.

7. The application according to claim 6, characterized in that, The soil in question is either arsenic-contaminated soil, antimony-contaminated soil, or arsenic-antimony contaminated soil.

8. A soil remediation method, characterized in that, This includes adding the arsenic-antimony contaminated soil remediation agent of claim 5 to the soil to be remediated, wherein the amount of the arsenic-antimony contaminated soil remediation agent added is 1% to 5% of the mass of the soil to be remediated.

9. The soil remediation method according to claim 8, characterized in that, It also includes adding water to the soil to be remediated after adding the arsenic and antimony contaminated soil remediation agent, with the curing time being 5 to 7 days and the amount of water being 25% to 40% of the mass of the soil to be remediated.

Images