A long-term evaluation method for remediation effect of antimony-arsenic co-contaminated soil
By employing freeze-thaw cycles and leachate treatment, the remediation effect of antimony-arsenic co-contaminated soil was evaluated, solving the problem that existing technologies cannot effectively assess the stability of antimony and arsenic, and enabling long-term evaluation and stability verification of the remediation effect of antimony-arsenic contaminated soil.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- INST OF AGRI RESOURCES & ENVIRONMENT SICHUAN ACAD OF AGRI SCI
- Filing Date
- 2023-02-23
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies lack effective methods to assess the stability of variable-valence metals such as antimony and arsenic in oxidative adsorption materials, especially in long-term field environments, making it impossible to verify the remediation effect of stabilization technologies on contaminated sites.
The method of combining freeze-thaw cycles with leachate treatment was adopted. The remediated soil samples were subjected to multiple freeze-thaw cycles under freeze-thaw conditions, and then leachate was carried out with leachate and leachate with specific pH values. The concentration of antimony and arsenic pollutants in the final leachate was detected and compared with whether it exceeded the Class III standard of surface water to evaluate the remediation effect.
This study provides a long-term method for evaluating the remediation effect of antimony and arsenic co-contaminated soil, ensuring that the stability of antimony and arsenic pollutants in the remediated soil meets surface water standards, and verifying the remediation effect of stabilization technology.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of soil remediation evaluation technology, and in particular relates to a long-term evaluation method for the remediation effect of antimony-arsenic combined pollution soil. Background Technology
[0002] Antimony (Sb) and arsenic (As) are metallic compounds belonging to Group V elements and have similar outer electron structures. Sb is a toxic and carcinogenic element, and Sb and its compounds have been listed as priority pollutants by the U.S. Environmental Protection Agency.
[0003] Currently, research on the safety and long-term effectiveness assessment of variable-valence metals such as antimony and arsenic under oxidative adsorption materials is relatively scarce both domestically and internationally. In order to verify the feasibility of stabilization technology for remediating contaminated sites, it is necessary to evaluate the remediation effect of oxidative adsorption materials, especially the long-term effectiveness assessment in the field.
[0004] Internationally, the evaluation methods for the effectiveness of stabilization remediation mainly include leaching tests and physical evaluation methods. Leaching tests are used to evaluate the leaching behavior of stabilization products; physical evaluation methods are used to predict the mixing of stabilizing agents with soil, the required amount of agents, and to compare the strength and durability before and after stabilization treatment. Currently, commonly used oscillating leaching tests include the most commonly used USEPA TCLP method, as well as the oscillating leaching test methods developed by SPLP and Japan and the EU. However, none of these methods evaluate the stability of variable-valence elements under oxidative adsorption conditions. Summary of the Invention
[0005] The purpose of this invention is to provide a long-term evaluation method for the remediation effect of antimony-arsenic co-contaminated soil. By evaluating the stability of variable-valence elements in the soil under oxidative adsorption conditions, this invention provides a certain technical reference for the remediation of antimony-arsenic co-contaminated soil.
[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:
[0007] This invention provides a long-term evaluation method for the remediation effect of antimony-arsenic combined contaminated soil, comprising the following steps:
[0008] Step 1: Pass the remediated experimental soil sample through a 2mm soil sieve to obtain a fine remediated experimental soil sample. Weigh 200g of the fine remediated experimental soil sample and place it in a 500ml polyethylene bottle.
[0009] Step 2: Pour leachate A into the polyethylene bottle mentioned above, so that leachate A completely submerges the fine-repaired experimental soil sample in the polyethylene bottle;
[0010] Step 3: Place the polyethylene bottle that has not been soaked in leachate A under freeze-thaw conditions for 32 freeze-thaw cycles;
[0011] Step 4: After completing the above 32 freeze-thaw cycles, place the polyethylene bottles after freeze-thaw cycles in an oven at 45°C to dry until constant weight. After drying, the soil is crushed, mixed and ground in sequence to obtain freeze-thaw soil samples, which are then bagged for later use.
[0012] Step 5: Place the above-mentioned freeze-thawed soil sample in the extraction solution B for soil sample extraction treatment. After the extraction treatment, the final extraction solution is obtained. The mass ratio of extraction solution B to freeze-thawed soil sample is 1:1.
[0013] Step Six: Detect the concentration of antimony and arsenic pollutants in the final leachate and compare it with the Class III surface water standard. If the concentration of antimony and arsenic pollutants in the final leachate exceeds the Class III surface water standard, it proves that the remediation effect is unqualified. If the concentration of antimony and arsenic pollutants in the final leachate does not exceed the Class III surface water standard, it proves that the remediation effect is qualified.
[0014] Preferably, for acidic contaminated soil, the evaluation method for the remediation effect of antimony-arsenic combined contaminated soil in this invention includes the following steps:
[0015] Step 1: Pass the remediated experimental soil sample through a 2mm soil sieve to obtain a fine remediated experimental soil sample. Weigh 200g of the fine remediated experimental soil sample and place it in a 500ml polyethylene bottle.
[0016] Step 2: Pour leachate A with a pH of 10.00 into the polyethylene bottle above, so that leachate A completely submerges the fine-repaired experimental soil sample in the polyethylene bottle;
[0017] Step 3: Place the polyethylene bottle that has not been soaked in leachate A under freeze-thaw conditions for 32 freeze-thaw cycles;
[0018] Step 4: After completing the above 32 freeze-thaw cycles, place the polyethylene bottles after freeze-thaw cycles in an oven at 45°C to dry until constant weight. After drying, the soil is crushed, mixed and ground in sequence to obtain freeze-thaw soil samples, which are then bagged for later use.
[0019] Step 5: Place the above-mentioned freeze-thawed soil sample in the extraction solution B for soil sample extraction treatment. After the extraction treatment, the final extraction solution is obtained. The mass ratio of extraction solution B to freeze-thawed soil sample is 1:1.
[0020] Step Six: Detect the concentration of antimony and arsenic pollutants in the final leachate and compare it with the Class III surface water standard. If the concentration of antimony and arsenic pollutants in the final leachate exceeds the Class III surface water standard, it proves that the remediation effect is unqualified. If the concentration of antimony and arsenic pollutants in the final leachate does not exceed the Class III surface water standard, it proves that the remediation effect is qualified.
[0021] Preferably, for alkaline contaminated soil, the evaluation method for the remediation effect of antimony-arsenic combined contaminated soil in this invention includes the following steps:
[0022] Step 1: Pass the remediated experimental soil sample through a 2mm soil sieve to obtain a fine remediated experimental soil sample. Weigh 200g of the fine remediated experimental soil sample and place it in a 500ml polyethylene bottle.
[0023] Step 2: Pour leachate A with a pH of 1.00 into the polyethylene bottle above, so that leachate A completely submerges the fine remediated experimental soil sample in the polyethylene bottle;
[0024] Step 3: Place the polyethylene bottle that has not been soaked in leachate A under freeze-thaw conditions for 32 freeze-thaw cycles;
[0025] Step 4: After completing the above 32 freeze-thaw cycles, place the polyethylene bottles after freeze-thaw cycles in an oven at 45°C to dry until constant weight. After drying, the soil is crushed, mixed and ground in sequence to obtain freeze-thaw soil samples, which are then bagged for later use.
[0026] Step 5: Place the above-mentioned freeze-thawed soil sample in the extraction solution B for soil sample extraction treatment. After the extraction treatment, the final extraction solution is obtained. The mass ratio of extraction solution B to freeze-thawed soil sample is 1:1.
[0027] Step Six: Detect the concentration of antimony and arsenic pollutants in the final leachate and compare it with the Class III surface water standard. If the concentration of antimony and arsenic pollutants in the final leachate exceeds the Class III surface water standard, it proves that the remediation effect is unqualified. If the concentration of antimony and arsenic pollutants in the final leachate does not exceed the Class III surface water standard, it proves that the remediation effect is qualified.
[0028] Preferably, the specific method of the freeze-thaw cycle includes: freezing a polyethylene bottle without leachate A at -75°C for 14 hours, and then incubating it at 15°C for 10 hours to form one freeze-thaw cycle. After 32 freeze-thaw cycles, the freeze-thaw cycle treatment of the soil sample is completed.
[0029] Preferably, in acidic contaminated soil, the leachate A is prepared using a 0.1 mol / L sodium hydroxide solution and pure water, and the pH of the prepared leachate A is 10.00.
[0030] Preferably, in alkaline contaminated soil, the leachate A is prepared using 0.1 mol / L nitric acid solution and pure water, and the pH of the prepared leachate A is 1.00.
[0031] Preferably, the extract B is a mixed solution of sulfuric acid and nitric acid, and its preparation method specifically includes: adding concentrated sulfuric acid and concentrated nitric acid to pure water at a mass ratio of 2:1, and controlling the pH of the extract B to be 3.15-3.25.
[0032] The present invention has the following beneficial effects:
[0033] This invention uses extract A for initial extraction, followed by freeze-thaw cycle treatment and drying to obtain freeze-thaw soil samples. Finally, extract B is used for secondary extraction to obtain the final extract for detection and analysis of antimony and arsenic pollutant concentrations. This allows for the assessment and verification of the feasibility of stabilization technology for remediating contaminated sites, thus providing a technical reference for the remediation of antimony and arsenic co-contaminated soils.
[0034] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Detailed Implementation
[0035] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0036] This invention explores the effects of iron-based materials on the stabilization and remediation of Sb and As in soil. Zero-valent iron powder (ZVIP) and potassium ferrate (K2FeO4) were selected, and the soil remediation effect was effectively evaluated by subjecting the soil remediated by iron-based materials to a series of treatments.
[0037] For contaminated soils with different acidity or alkalinity, different evaluation methods are selected for acidic contaminated soils (pH < 7) or alkaline contaminated soils (pH ≥ 7). After the contaminated soils are remediated, they are air-dried, ground, and then passed through a 2mm soil sieve for later use.
[0038] This invention provides a long-term evaluation method for the remediation effect of antimony-arsenic combined contaminated soil, comprising the following steps:
[0039] Step 1: Pass the remediated experimental soil sample through a 2mm soil sieve to obtain a fine remediated experimental soil sample. Weigh 200g of the fine remediated experimental soil sample and place it in a 500ml polyethylene bottle.
[0040] Step 2: Pour leachate A into the polyethylene bottle mentioned above, so that leachate A completely submerges the fine-repaired experimental soil sample in the polyethylene bottle, making the soil sample completely wet and submerged by 2cm.
[0041] Step 3: Place the polyethylene bottle without leachate A under freeze-thaw conditions for 32 freeze-thaw cycles. The specific method of freeze-thaw cycle includes: freezing the polyethylene bottle without leachate A at -75℃ for 14 hours, and then incubating it at 15℃ for 10 hours to form one freeze-thaw cycle.
[0042] Step 4: After completing the above 32 freeze-thaw cycles, place the polyethylene bottles after the freeze-thaw cycles in an oven at 45°C to dry until constant weight (the weight of the polyethylene bottles should not differ by more than 2.5g at 24-hour intervals). After drying, the soil is crushed, mixed and ground in sequence to obtain freeze-thaw soil samples, which are then bagged for later use.
[0043] Step 5: Place the above-mentioned freeze-thawed soil sample in leaching solution B for soil sample leaching treatment. After leaching treatment, the final leaching solution is obtained. The mass ratio of leaching solution B to freeze-thawed soil sample is 1:1. The leaching solution B is a mixed solution of sulfuric acid and nitric acid. The specific preparation method includes: adding concentrated sulfuric acid and concentrated nitric acid to pure water at a mass ratio of 2:1 (about 2 drops of mixed solution are added to 1L of pure water), and controlling the pH of the leaching solution B to 3.15-3.25. The leaching solution B is used to determine the leaching toxicity of heavy metals in the sample.
[0044] Step Six: Detect the concentration of antimony and arsenic pollutants in the final leachate and compare it with the Class III surface water standard. If the concentration of antimony and arsenic pollutants in the final leachate exceeds the Class III surface water standard, it proves that the remediation effect is unqualified. If the concentration of antimony and arsenic pollutants in the final leachate does not exceed the Class III surface water standard, it proves that the remediation effect is qualified.
[0045] For acidic contaminated soil, the long-term effectiveness assessment method for remediation of antimony-arsenic combined contaminated soil of the present invention includes the following steps:
[0046] Step 1: Pass the remediated experimental soil sample through a 2mm soil sieve to obtain a fine remediated experimental soil sample. Weigh 200g of the fine remediated experimental soil sample and place it in a 500ml polyethylene bottle.
[0047] Step 2: Pour leachate A with a pH of 10.00 into the polyethylene bottle, so that leachate A completely submerges the fine-repaired soil sample in the polyethylene bottle, making the soil sample completely wet and submerged by 2 cm; leachate A is prepared by using 0.1 mol / L sodium hydroxide solution and pure water.
[0048] Step 3: Place the polyethylene bottle without leachate A under freeze-thaw conditions for 32 freeze-thaw cycles. The specific method of freeze-thaw cycle includes: freezing the polyethylene bottle without leachate A at -75℃ for 14 hours, and then incubating it at 15℃ for 10 hours to form one freeze-thaw cycle.
[0049] Step 4: After completing the above 32 freeze-thaw cycles, place the polyethylene bottles after the freeze-thaw cycles in an oven at 45°C to dry until constant weight (the weight of the polyethylene bottles should not differ by more than 2.5g at 24-hour intervals). After drying, the soil is crushed, mixed and ground in sequence to obtain freeze-thaw soil samples, which are then bagged for later use.
[0050] Step 5: Place the above-mentioned freeze-thawed soil sample in leaching solution B for soil sample leaching treatment. After leaching treatment, the final leaching solution is obtained. The mass ratio of leaching solution B to freeze-thawed soil sample is 1:1. The leaching solution B is a mixed solution of sulfuric acid and nitric acid. The specific preparation method includes: adding concentrated sulfuric acid and concentrated nitric acid to pure water at a mass ratio of 2:1, and controlling the pH of the leaching solution B to 3.15-3.25.
[0051] Step Six: Detect the concentration of antimony and arsenic pollutants in the final leachate and compare it with the Class III surface water standard. If the concentration of antimony and arsenic pollutants in the final leachate exceeds the Class III surface water standard, it proves that the remediation effect is unqualified. If the concentration of antimony and arsenic pollutants in the final leachate does not exceed the Class III surface water standard, it proves that the remediation effect is qualified.
[0052] For alkaline contaminated soil, the long-term effectiveness assessment method for remediation of antimony-arsenic combined contaminated soil of the present invention includes the following steps:
[0053] Step 1: Pass the remediated experimental soil sample through a 2mm soil sieve to obtain a fine remediated experimental soil sample. Weigh 200g of the fine remediated experimental soil sample and place it in a 500ml polyethylene bottle.
[0054] Step 2: Pour leachate A with a pH of 1.00 into the polyethylene bottle, so that leachate A completely submerges the fine-repaired soil sample in the polyethylene bottle, making the soil sample completely wet and submerged by 2 cm; leachate A is prepared by using 0.1 mol / L nitric acid solution and pure water.
[0055] Step 3: Place the polyethylene bottle without leachate A under freeze-thaw conditions for 32 freeze-thaw cycles. The specific method of freeze-thaw cycle includes: freezing the polyethylene bottle without leachate A at -75℃ for 14 hours, and then incubating it at 15℃ for 10 hours to form one freeze-thaw cycle.
[0056] Step 4: After completing the above 32 freeze-thaw cycles, place the polyethylene bottles after the freeze-thaw cycles in an oven at 45°C to dry until constant weight (the weight of the polyethylene bottles should not differ by more than 2.5g at 24-hour intervals). After drying, the soil is crushed, mixed and ground in sequence to obtain freeze-thaw soil samples, which are then bagged for later use.
[0057] Step 5: Place the above-mentioned freeze-thawed soil sample in leaching solution B for soil sample leaching treatment. After leaching treatment, the final leaching solution is obtained. The mass ratio of leaching solution B to freeze-thawed soil sample is 1:1. The leaching solution B is a mixed solution of sulfuric acid and nitric acid. The specific preparation method includes: adding concentrated sulfuric acid and concentrated nitric acid to pure water at a mass ratio of 2:1, and controlling the pH of the leaching solution B to 3.15-3.25.
[0058] Step Six: Detect the concentration of antimony and arsenic pollutants in the final leachate and compare it with the Class III surface water standard. If the concentration of antimony and arsenic pollutants in the final leachate exceeds the Class III surface water standard, it proves that the remediation effect is unqualified. If the concentration of antimony and arsenic pollutants in the final leachate does not exceed the Class III surface water standard, it proves that the remediation effect is qualified.
[0059] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0060] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A long-term evaluation method for the remediation effect of antimony-arsenic combined contaminated soil, characterized in that, Includes the following steps: Step 1: Pass the remediated experimental soil sample through a 2 mm soil sieve to obtain a fine remediated experimental soil sample. Weigh 200 g of the fine remediated experimental soil sample and place it in a 500 ml polyethylene bottle. Step 2: Pour leachate A into the polyethylene bottle mentioned above, so that leachate A completely submerges the fine-repaired experimental soil sample in the polyethylene bottle; Step 3: Place the polyethylene bottle that has not been soaked in leachate A under freeze-thaw conditions for 32 freeze-thaw cycles; Step 4: After completing the above 32 freeze-thaw cycles, place the polyethylene bottles after freeze-thaw cycles in an oven at 45°C to dry until constant weight. After drying, the soil is crushed, mixed and ground in sequence to obtain freeze-thaw soil samples, which are then bagged for later use. Step 5: Place the above-mentioned freeze-thawed soil sample in the extraction solution B for soil sample extraction treatment. After the extraction treatment, the final extraction solution is obtained. The mass ratio of extraction solution B to freeze-thawed soil sample is 1:
1. Step 6: Detect the concentration of antimony and arsenic pollutants in the final leachate and compare it with the Class III standard for surface water. If the concentration of antimony and arsenic pollutants in the final leachate exceeds the Class III standard for surface water, it proves that the remediation effect is unqualified. If the concentration of antimony and arsenic pollutants in the final leachate does not exceed the Class III standard for surface water, it proves that the remediation effect is qualified. For acid-contaminated soils, the pH of leachate A is 10.00; and / or For alkaline contaminated soil, the pH of leachate A is 1.00; The extract B is a mixed solution of sulfuric acid and nitric acid, and its preparation method specifically includes: adding concentrated sulfuric acid and concentrated nitric acid to pure water at a mass ratio of 2:1, and controlling the pH of the extract B to be 3.15-3.
25.
2. The long-term evaluation method for the remediation effect of antimony-arsenic combined contaminated soil according to claim 1, characterized in that, The specific method of the freeze-thaw cycle includes: freezing a polyethylene bottle without leachate A at -75°C for 14 hours, and then incubating it at 15°C for 10 hours to form one freeze-thaw cycle. After 32 freeze-thaw cycles, the freeze-thaw cycle treatment of the soil sample is completed.
3. The long-term evaluation method for the remediation effect of antimony-arsenic combined contaminated soil according to claim 1, characterized in that, In acid-contaminated soil, the leachate A is prepared using 0.1 mol / L sodium hydroxide solution and pure water, and the pH of the prepared leachate A is 10.
00.
4. The long-term evaluation method for the remediation effect of antimony-arsenic combined contaminated soil according to claim 1, characterized in that, In alkaline contaminated soil, the leachate A is prepared using 0.1 mol / L nitric acid solution and pure water, and the pH of the prepared leachate A is 1.00.