A method for preparing a permeable reactive wall slow-release packing and its application

Abstract

This invention belongs to the field of water pollution remediation technology, specifically relating to a method for preparing a permeable reactive wall slow-release packing and its application. The method for preparing the permeable reactive wall slow-release packing provided by this invention includes the following steps: mixing adsorption-degradation materials, embedding agents, nanoporous materials, and water, followed by freeze-thaw cycles, drying, acid solution treatment, and secondary drying to obtain the permeable reactive wall slow-release packing; the adsorption-degradation materials include reduced iron powder, biochar, and persulfate. The permeable reactive wall slow-release packing prepared by this invention has a strong adsorption capacity for complex pollutants and can achieve long-term effective remediation. Simultaneously, the block-shaped slow-release packing effectively avoids secondary pollution to the environment caused by scattering during construction and dismantling.

Description

Technical Field

[0001] This invention belongs to the field of water pollution remediation technology, specifically relating to a method for preparing a permeable reactive wall slow-release packing and its application. Background Technology

[0002] Permeable reactive barrier (PRB) technology involves installing a wall filled with activated packing material underground at a contaminated site, creating a passive reaction zone to intercept or remove pollutants from groundwater. General research and applications typically design implementation schemes for activated packing material based on the type of soil and groundwater pollution. Existing PRB packing materials are primarily composed of particulate matter, which impacts the surrounding environment during installation and removal. For example, material spillage and the contamination of surrounding soil by fine particles of packing material adsorbing and encapsulating pollutants during removal are common problems. Furthermore, the design of existing PRB packing materials is difficult to meet the remediation needs of complex groundwater pollution, such as fluorides, cadmium, copper, lead, and chromium, especially for emerging pollutants like microplastics. Moreover, their pollution remediation capabilities significantly decrease or even become ineffective over extended operation. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the existing permeable reactive walls, which are difficult to meet the needs of underground complex pollution remediation, whose remediation capacity decreases significantly with the length of operation time and is easy to scatter and re-pollute the soil. Thus, the present invention provides a method for preparing a slow-release filler for a permeable reactive wall and its application.

[0004] This invention provides a method for preparing a permeable reactive wall slow-release packing material, comprising the following steps:

[0005] The adsorption-degradation material, encapsulating agent, nanoporous material and water are mixed and then subjected to freeze-thaw cycle, drying, acid solution treatment and secondary drying to obtain the permeable reactive wall slow-release filler;

[0006] The adsorption and degradation materials include reduced iron powder, biochar, and persulfate.

[0007] The acid solution described in this invention is a solution with acid as solute and water as solvent.

[0008] Preferably, the preparation method of the permeable reactive wall slow-release packing includes the following steps:

[0009] 1) Mix the embedding agent with water to obtain an embedding agent mixture solution;

[0010] 2) Mix the encapsulating agent solution, adsorption degradation material and nanoporous material from step 1), pour the mixture into a mold, and after freeze-thaw and drying, obtain block-shaped slow-release filler;

[0011] 3) The block-shaped slow-release packing material from step 2) is treated with acid solution and dried twice to obtain the permeable reactive wall slow-release packing material.

[0012] This invention does not impose specific limitations on the size and shape of the mold; any suitable mold can be selected, such as a mold with a diameter of 240mm*115mm*55mm.

[0013] Preferably, the freeze-thaw step includes first freezing and then thawing to form a single freeze-thaw process. For example, a mixture of adsorbent degradation material, encapsulating agent, nanoporous material, and water is first frozen and then thawed to form a single freeze-thaw process; or, a mixture of encapsulating agent solution, adsorbent degradation material, and nanoporous material is first frozen and then thawed to form a single freeze-thaw process.

[0014] Preferably, the freezing temperature of the freezing treatment is -17.5±2.5℃, and the freezing time is 11-13h;

[0015] And / or, the thawing temperature of the thawing treatment is 5-20℃, and the thawing time is 11-13h;

[0016] And / or, the freeze-thaw step includes 5-15 freeze-thaw cycles.

[0017] Preferably, the acid solution treatment step involves immersing the block-shaped slow-release filler obtained after freeze-thaw and drying in an acid solution.

[0018] The immersion time is 5-10 minutes;

[0019] And / or, the molar concentration of the acid in the acid solution is 0.8-1 mol / L;

[0020] And / or, the acid in the acid solution is selected from at least one of inorganic acids and / or organic acids;

[0021] Preferably, the acid in the acid solution is selected from organic acids;

[0022] More preferably, the acid in the acid solution is selected from C4-C8 ternary organic carboxylic acids;

[0023] More preferably, the acid in the acid solution is selected from citric acid.

[0024] Optionally, the acid in the acid solution is selected from at least one of hydrochloric acid and nitric acid.

[0025] Preferably, the mass ratio of the adsorption and degradation material, the encapsulating agent, the nanoporous material, and water is (10-30):(3-15):(1-10):(30-40);

[0026] And / or, the molar ratio of the nanoporous material to the acid in the acid solution is 1:(1.5-3);

[0027] The persulfate is selected from at least one of potassium persulfate and sodium persulfate;

[0028] And / or, the encapsulating agent is selected from at least one of sodium alginate and polyvinyl alcohol;

[0029] And / or, the nanoporous material includes nanocarbonate.

[0030] Optionally, the polyvinyl alcohol is type 2488 polyvinyl alcohol (PVA2488);

[0031] Preferably, the adsorption and degradation material further includes a grinding process, wherein the grinding speed is 500-600 rpm and the grinding time is 20-60 min;

[0032] And / or, the mass ratio of the reduced iron powder, biochar, and persulfate is (1-10):1:(10-20);

[0033] And / or, the encapsulating agent is sodium alginate and polyvinyl alcohol;

[0034] The mass ratio of sodium alginate to polyvinyl alcohol is (2-14):1;

[0035] And / or, the nanoporous material is a nano-carbonate;

[0036] Optionally, the nano carbonate is selected from at least one of nano sodium carbonate and nano potassium carbonate.

[0037] Optionally, the acid solution is an aqueous solution of citric acid.

[0038] In this invention, nano-carbonate, encapsulating agent, adsorption and degradation material, and water are mixed and then impregnated with an acid solution. The acid reacts with the nano-carbonate to produce carbon dioxide and form bubbles, which create vacant spots and further form nanoscale pores, thereby further promoting the adsorption of pollutants by the filler.

[0039] Preferably, the drying temperature is 50-120℃ and the drying time is 1-5 hours;

[0040] And / or, the secondary drying temperature is 50-120℃, and the secondary drying time is 1-5h;

[0041] Preferably, the drying temperature is 60-110℃, and the secondary drying temperature is 60-110℃;

[0042] And / or, the acid solution treatment further includes a water treatment step;

[0043] The water treatment step includes immersing the acid-treated material in water for soaking.

[0044] The volume ratio of water in the water treatment step to the volume of acid solution in the acid solution treatment step is (1-2):1;

[0045] The immersion treatment in the water is carried out for 10-15 minutes.

[0046] Preferably, in step 1), the mixing temperature is 50-70℃, the mixing time is 3-5h, and the stirring speed during mixing is 150-180rpm.

[0047] And / or, the stirring speed in step 2) is 150-200 rpm and the stirring time is 5-10 min.

[0048] The present invention also provides an application of the permeable reactive wall slow-release packing prepared by the above-described method in the remediation of groundwater pollution.

[0049] The technical solution of this invention has the following advantages:

[0050] 1. The preparation method of the slow-release packing material for the permeable reactive wall provided by the present invention includes the following steps: mixing adsorption and degradation materials, embedding agents, nanoporous materials and water, followed by freeze-thaw cycles, drying, acid solution treatment, and secondary drying to obtain the slow-release packing material for the permeable reactive wall; the adsorption and degradation materials include reduced iron powder, biochar and persulfate. The present invention mixes the adsorption and degradation materials, embedding agents, nanoporous materials and water. During the mixing process, the nanoporous materials are adsorbed onto the surface or interior of the biochar. After acid solution treatment, nanoscale pores are formed on the surface or interior of the biochar, which enriches the pore structure of the slow-release packing material for the permeable reactive wall, thereby providing strong adsorption capacity, adsorbing microplastics, stabilizing fluorides, and simultaneously adsorbing heavy metals such as cadmium, copper, lead, and chromium; the embedding agent can fix reduced iron powder and sodium sulfate on the surface and interior of the biochar and in the nanoscale pores formed on its surface or interior, allowing the remediation agent to be released slowly. Therefore, the pollution control capacity of the permeable reactive wall increases with the length of operation. There will be no significant reduction. Through freeze-thaw cycles, the slow-release filler not only forms a stable block-shaped slow-release filler, effectively avoiding potential environmental impacts during construction and dismantling, but also ensures the stable existence of nanoscale pores formed on or inside the biochar, further guaranteeing the strong adsorption capacity of the slow-release filler. Simultaneously, freeze-thaw cycles also reinforce the fixation effect of the embedding agent, making reduced iron powder and sodium sulfate more stable on the surface, inside, and within the nanoscale pores formed on or inside the biochar, further ensuring the slow release of the remediation agent. The resulting permeable reactive wall slow-release filler exhibits significant long-term remediation properties. The permeable reactive wall slow-release filler prepared by the synergistic cooperation of the various steps in this invention has a strong adsorption capacity for complex pollutants and can achieve long-term effective remediation. Furthermore, the block-shaped slow-release filler effectively avoids secondary pollution caused by scattering during construction and dismantling. Attached Figure Description

[0051] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0052] Figure 1 A schematic diagram of the permeation reactor column used in the test examples of this invention. Detailed Implementation

[0053] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0054] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0055] Example 1

[0056] This embodiment provides a method for preparing a permeable reactive wall slow-release packing material, including the following steps:

[0057] 1) Mix 100g sodium alginate, 10g polyvinyl alcohol (type 2488), and 350g water at a mixing temperature of 70℃ for 5 hours and a stirring speed of 150 rpm to obtain an encapsulating agent mixture solution.

[0058] 2) The encapsulating agent mixture from step 1), 200g of adsorption degradation material (obtained by ball milling reduced iron powder, biochar and sodium persulfate mixed at a mass ratio of 5:1:14 for 30min at 500rpm) and 70g of nano sodium carbonate were stirred at 200rpm for 7min to form a mixture. The mixture was poured into a mold and subjected to 9 freeze-thaw cycles (freezing temperature -18℃, freezing time 12h, thawing temperature 12.5℃, thawing time 12h), and dried to obtain a block-shaped slow-release filler. The drying temperature was 80℃ and the drying time was 2h.

[0059] 3) The block-shaped slow-release packing material from step 2) is immersed in 1.8L of 1mol / L citric acid aqueous solution for 8min, and then immersed in 1.8L of water for another 10min. After drying, the permeable reactive wall slow-release packing material is obtained. The secondary drying temperature is 80℃ and the secondary drying time is 2h.

[0060] Example 2

[0061] This embodiment provides a method for preparing a permeable reactive wall slow-release packing material, including the following steps:

[0062] 1) Mix 140g sodium alginate, 10g polyvinyl alcohol (type 2488) and 400g water at a mixing temperature of 50℃ for 3 hours and a stirring speed of 180 rpm to obtain an encapsulating agent mixture solution.

[0063] 2) The encapsulating agent mixture from step 1), 300g of adsorption degradation material (obtained by ball milling reduced iron powder, biochar and sodium persulfate mixed in a mass ratio of 1:1:10 at 500rpm for 30min) and 100g of nano sodium carbonate were stirred at 150rpm for 10min to form a mixture. The mixture was poured into a mold and subjected to 5 freeze-thaw cycles (freezing temperature -15℃, freezing time 12h, thawing temperature 5℃, thawing time 12h). After drying, block-shaped slow-release filler was obtained, wherein the drying temperature was 110℃ and the drying time was 1h.

[0064] 3) The block-shaped slow-release packing material from step 2) is immersed in 1.5L of 1mol / L citric acid water for 10min, and then immersed in 1.5L of water for another 15min. After drying, the permeable reactive wall slow-release packing material is obtained. The secondary drying temperature is 110℃ and the secondary drying time is 1h.

[0065] Example 3

[0066] This embodiment provides a method for preparing a permeable reactive wall slow-release packing material, including the following steps:

[0067] 1) Mix 30g sodium alginate, 10g polyvinyl alcohol (type 2488) and 300g water at a mixing temperature of 70℃ for 5 hours and a stirring speed of 150 rpm to obtain an encapsulating agent mixture solution.

[0068] 2) The encapsulating agent mixture from step 1), 100g of adsorption degradation material (obtained by ball milling reduced iron powder, biochar and potassium persulfate mixed at a mass ratio of 10:1:20 at 600rpm for 20min) and 20g of nano potassium carbonate were stirred at 170rpm for 5min to form a mixture. The mixture was poured into a mold and subjected to 15 freeze-thaw cycles (freezing temperature -20℃, freezing time 12h, thawing temperature 20℃, thawing time 12h). After drying, block-shaped slow-release filler was obtained, wherein the drying temperature was 60℃ and the drying time was 5h.

[0069] 3) The block-shaped slow-release packing material from step 2) is immersed in 0.5L of 0.8mol / L citric acid water for 5min, and then immersed in 0.5L of water for another 10min. After drying, the permeable reactive wall slow-release packing material is obtained. The secondary drying temperature is 60℃ and the secondary drying time is 5h.

[0070] Comparative Example 1

[0071] This comparative example provides a method for preparing a permeable reactive wall slow-release packing material, comprising the following steps:

[0072] 1) Mix 100g sodium alginate, 10g polyvinyl alcohol (type 2488), and 350g water at a mixing temperature of 70℃ for 5 hours and a stirring speed of 150 rpm to obtain an encapsulating agent mixture solution.

[0073] 2) The encapsulating agent mixture from step 1), 200g of adsorption degradation material (obtained by ball milling reduced iron powder, biochar and sodium persulfate mixed at a mass ratio of 5:1:14 for 30min at 500rpm) and 70g of nano sodium carbonate were stirred at a stirring speed of 200rpm for 7min to form a mixture. The mixture was poured into a mold and dried to obtain a block-shaped slow-release filler. The drying temperature was 80℃ and the drying time was 2h.

[0074] 3) The block-shaped slow-release packing material from step 2) is immersed in 1.8L of 1mol / L citric acid aqueous solution for 8min, and then immersed in 1.8L of water for another 10min. After drying, the permeable reactive wall slow-release packing material is obtained. The secondary drying temperature is 80℃ and the secondary drying time is 2h.

[0075] Comparative Example 2

[0076] This comparative example provides a method for preparing a permeable reactive wall slow-release packing material, comprising the following steps:

[0077] 1) Mix 100g sodium alginate, 10g polyvinyl alcohol (type 2488), and 350g water at a mixing temperature of 70℃ for 5 hours and a stirring speed of 150 rpm to obtain an encapsulating agent mixture solution.

[0078] 2) The encapsulating agent mixture from step 1) and 200g of adsorption degradation material (obtained by ball milling reduced iron powder, biochar and sodium persulfate mixed at a mass ratio of 5:1:14 at 500rpm for 30min) were stirred at 200rpm for 7min to form a mixture. The mixture was poured into a mold and subjected to 9 freeze-thaw cycles (freezing temperature -18℃, freezing time 12h, thawing temperature 12.5℃, thawing time 12h), and dried to obtain block-shaped slow-release filler. The drying temperature was 80℃ and the drying time was 2h.

[0079] 3) The block-shaped slow-release packing material from step 2) is immersed in 1.8L of 1mol / L citric acid aqueous solution for 8min, and then immersed in 1.8L of water for another 10min. After drying, the permeable reactive wall slow-release packing material is obtained. The secondary drying temperature is 80℃ and the secondary drying time is 2h.

[0080] Comparative Example 3

[0081] This comparative example provides a method for preparing a permeable reactive wall slow-release packing material, comprising the following steps:

[0082] 1) Mix 100g sodium alginate, 10g polyvinyl alcohol (type 2488), and 350g water at a mixing temperature of 70℃ for 5 hours and a stirring speed of 150 rpm to obtain an encapsulating agent mixture solution.

[0083] 2) The encapsulating agent mixture from step 1) was mixed with 200g of adsorption degradation material (obtained by ball milling reduced iron powder, biochar and sodium persulfate mixed at a mass ratio of 5:1:14 at 500rpm for 30min) and 70g of nano sodium carbonate. The mixture was stirred at 200rpm for 7min to form a mixture. The mixture was poured into a mold and subjected to 9 freeze-thaw cycles (freezing temperature -18℃, freezing time 12h, thawing temperature 12.5℃, thawing time 12h). After drying, block-shaped slow-release filler was obtained, wherein the drying temperature was 80℃ and the drying time was 2h.

[0084] 3) The block-shaped slow-release packing material from step 2) is immersed in 1.8L of water for 10 minutes and dried to obtain the permeable reactive wall slow-release packing material. The secondary drying temperature is 80℃ and the secondary drying time is 2 hours.

[0085] Comparative Example 4

[0086] This comparative example provides a method for preparing a permeable reactive wall slow-release packing material, comprising the following steps:

[0087] 1) Mix 350g water, 200g adsorption and degradation material (obtained by ball milling reduced iron powder, biochar and sodium persulfate mixed at a mass ratio of 5:1:14 at 500rpm for 30min) and 70g nano sodium carbonate at a stirring speed of 200rpm for 7min to form a mixture. Pour the mixture into a mold and allow it to undergo 9 freeze-thaw cycles (freezing temperature -18℃, freezing time 12h, thawing temperature 12.5℃, thawing time 12h). Dry the mixture to obtain block-shaped slow-release filler, wherein the drying temperature is 80℃ and the drying time is 2h.

[0088] 2) The block-shaped slow-release packing material from step 1) is immersed in 1.8L of 1mol / L citric acid aqueous solution for 8min, and then immersed in 1.8L of water for another 10min. After drying, the permeable reactive wall slow-release packing material is obtained. The secondary drying temperature is 80℃ and the secondary drying time is 2h.

[0089] Test case

[0090] In this test example, the permeable reactive wall slow-release packing material prepared in Examples 1-3 or Comparative Examples 1-4 was filled into a permeable reactor column (e.g., Figure 1As shown, the packing height is 80cm, and the diameter of the permeable reactor column is 5cm. A composite pollutant solution is introduced through the inlet at the bottom. The composite pollutant solution will pass evenly through the permeable reaction wall slow-release packing in the permeable reactor column and flow out from the outlet, thus simulating the interception and removal of pollutants in groundwater by a permeable reaction wall. The composite pollutant solution is a composite pollutant simulation solution prepared under laboratory conditions. The composite pollutant simulation solution is prepared using polyethylene (molecular weight 200-220), sodium fluoride, cadmium dichloride, copper dichloride, lead dichloride, and potassium dichromate as raw materials. The concentration of polyethylene in the prepared solution is 100mg / L, the concentration of sodium fluoride is 10mg / L, the concentration of cadmium is 10mg / L, the concentration of copper is 10mg / L, the concentration of lead is 10mg / L, and the concentration of hexavalent chromium is 10mg / L. The composite pollutant solution was introduced into the inlet at a flow rate of 0.5 ml / min, and timing was started from the 14th and 50th days of continuous introduction. Samples were taken from the sampling valve at the top of the permeate reactor column test device, 10 cm below the packing height, to monitor changes in pollutant concentration. The concentration of polyethylene was determined by Raman spectroscopy, the concentrations of cadmium, copper, lead, and chromium were determined by ICP-MS, and the concentration of sodium fluoride was determined by fluorine reagent spectrophotometry. The test results are shown in Table 1.

[0091] Table 1

[0092]

[0093] The slow-release filler prepared in this embodiment of the invention is a block-shaped slow-release filler. In the above simulation test, it maintained a good block shape. After the reaction, no small particles were scattered. In the application process, it can effectively reduce the pollution of the surrounding soil by the fine particles of filler that adsorb and encapsulate pollutants during dismantling.

[0094] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a permeable reactive wall slow-release packing material, characterized in that, Includes the following steps: 1) Mix the embedding agent with water to obtain an embedding agent mixture solution; 2) Stir and mix the encapsulating agent mixture, adsorption degradation material and nanoporous material from step 1), pour into a mold, and after freeze-thaw and drying, obtain block-shaped slow-release filler; 3) The blocky slow-release packing material from step 2) is treated with acid solution and dried twice to obtain the permeable reactive wall slow-release packing material; The encapsulating agent is sodium alginate and polyvinyl alcohol; The adsorption and degradation materials include reduced iron powder, biochar, and persulfate; The nanoporous material includes nano carbonates.

2. The method for preparing the permeable reactive wall slow-release packing material according to claim 1, characterized in that, The freeze-thaw process includes first freezing and then thawing to form a freeze-thaw cycle.

3. The method for preparing the permeable reactive wall slow-release packing material according to claim 2, characterized in that, The freezing temperature for the freezing treatment is -17.5±2.5℃, and the freezing time is 11-13 hours. And / or, the thawing temperature of the thawing treatment is 5-20℃, and the thawing time is 11-13h; And / or, the freeze-thaw step includes 5-15 freeze-thaw cycles.

4. The method for preparing the permeable reactive wall slow-release packing material according to any one of claims 1-3, characterized in that, The acid solution treatment step involves immersing the block-shaped slow-release filler obtained after freeze-thawing and drying in an acid solution. The immersion time is 5-10 minutes; And / or, the molar concentration of the acid in the acid solution is 0.8-1 mol / L; And / or, the acid in the acid solution is selected from at least one of inorganic acids and / or organic acids.

5. The method for preparing the permeable reactive wall slow-release packing material according to claim 4, characterized in that, The acid in the acid solution is selected from organic acids.

6. The method for preparing the permeable reactive wall slow-release packing material according to claim 4, characterized in that, The acid in the acid solution is selected from C4-C8 ternary organic carboxylic acids.

7. The method for preparing the permeable reactive wall slow-release packing material according to claim 4, characterized in that, The acid in the acid solution is selected from citric acid.

8. The method for preparing the permeable reactive wall slow-release packing material according to any one of claims 1-3, characterized in that, The mass ratio of the adsorption and degradation material, the encapsulating agent, the nanoporous material and water is (10-30):(3-15):(1-10):(30-40); And / or, the molar ratio of the nanoporous material to the acid in the acid solution is 1:(1.5-3). The persulfate is selected from at least one of potassium persulfate and sodium persulfate.

9. The method for preparing the permeable reactive wall slow-release packing material according to any one of claims 1-3, characterized in that, The adsorption and degradation material also includes a grinding process, with a grinding speed of 500-600 rpm and a grinding time of 20-60 min; And / or, the mass ratio of the reduced iron powder, biochar, and persulfate is (1-10):1:(10-20); The mass ratio of sodium alginate to polyvinyl alcohol is (2-14):1; And / or, the nanoporous material is a nano carbonate.

10. The method for preparing the permeable reactive wall slow-release packing material according to any one of claims 1-3, characterized in that, The nano carbonate is selected from at least one of nano sodium carbonate and nano potassium carbonate.

11. The method for preparing the permeable reactive wall slow-release packing material according to any one of claims 1-3, characterized in that, The drying temperature is 50-120℃, and the drying time is 1-5 hours; And / or, the secondary drying temperature is 50-120℃, and the secondary drying time is 1-5h; And / or, the acid solution treatment further includes a water treatment step; The water treatment step includes immersing the acid-treated material in water for soaking. The volume ratio of water in the water treatment step to the volume of acid solution in the acid solution treatment step is (1-2):1; The immersion treatment in the water is carried out for 10-15 minutes.

12. The method for preparing the permeable reactive wall slow-release packing material according to claim 11, characterized in that, The drying temperature is 60-110℃, and the secondary drying temperature is 60-110℃.

13. The method for preparing the permeable reactive wall slow-release packing material according to claim 1, characterized in that, In step 1), the mixing temperature is 50-70℃, the mixing time is 3-5 hours, and the stirring speed is 150-180 rpm. And / or, the stirring speed in step 2) is 150-200 rpm and the stirring time is 5-10 min.

14. The application of the permeable reactive wall slow-release packing prepared by the preparation method of any one of claims 1-13 in the remediation of groundwater pollution.

Images