Permeable reactive barrier filling material, method for its production and use

Abstract

The application provides a permeable reaction wall filling material and a preparation method and application thereof. The permeable reaction wall filling material provided by the application comprises a first molecular sieve, a second molecular sieve, a metal oxide, a mesoporous material and a binder, the silicon-aluminum ratio of the first molecular sieve is greater than or equal to 200, and the silicon-aluminum ratio of the second molecular sieve is 5-80. The permeable reaction wall filling material of the application comprises two molecular sieves with different silicon-aluminum ratios and a metal oxide, can effectively combine the principles of adsorption and oxidation, is applied in the treatment of soil and groundwater, has good treatment performance on low-concentration organic pollutants in water, and has excellent regeneration performance.

Description

Technical Field

[0001] This invention belongs to the field of organic polluted soil remediation technology, specifically relating to a permeable reactive wall filling material, its preparation method, and its application. Background Technology

[0002] Due to historical deficiencies in environmental awareness or accidents, many countries have large amounts of contaminated soil and groundwater. European and American countries, with their longer industrialization periods, began addressing soil and groundwater pollution earlier. With people's pursuit of a better life, the comprehensive management of contaminated soil and groundwater in China has also gained attention. Contaminated sites can be mainly classified into heavy metal contamination, organic matter contamination, radioactive material contamination, and combined contamination. Among these, the Permeable Reactive Barrier (PRB) is an in-situ groundwater remediation technology with promising applications in various types of contaminated site remediation. It features long lifespan, land-saving in-situ remediation, and minimal environmental impact. Its core lies in the development of permeable reactive barrier filling materials.

[0003] For organic polluted soil remediation technologies, permeable reactive barrier filling materials can be categorized into adsorption-type, chemical oxidation-type, and biodegradable-type based on their operating principles. Commonly used adsorption-type materials include activated carbon, zeolite molecular sieves, aluminosilicates, and organic carbon. Chemical reduction-type materials primarily use metal oxides that can undergo oxidation-reduction reactions as active centers, combined with oxidants to oxidize organic pollutants in water. Biodegradable materials mainly involve loading microorganisms onto active carriers, such as activated carbon, activated clay, quartz sand, bentonite, and natural zeolite, to degrade organic pollutants in water through biochemical reactions.

[0004] CN113979508A discloses a filling material, preparation method, and application of a permeable reactive barrier. The filling material provided by this method is a solid microsphere, mainly composed of zero-valent iron, activated carbon, tourmaline, and a binder. It primarily eliminates petroleum hydrocarbon pollution in water by forming an iron-carbon galvanic cell underground with zero-valent iron and a carbon source. However, the material provided by this method cannot be regenerated in situ and gradually deteriorates after use, making it unsuitable for long-term operation or reuse.

[0005] CN110467250A discloses a microfiber composite NaA molecular sieve membrane-nano zero-valent iron composite material, its preparation method, and its application in wastewater treatment. The method involves immersing the microfiber composite NaA molecular sieve membrane in a ferrous solution for 20-40 minutes, then adding sodium borohydride solution dropwise to the surface of the membrane. After 1-3 hours of dropwise addition, the membrane is filtered, washed, and vacuum dried to obtain the microfiber composite NaA molecular sieve membrane-nano zero-valent iron composite material. This microfiber composite NaA molecular sieve membrane-nano zero-valent iron composite material can further remove azo dyes and COD from wastewater after treating heavy metals. However, this method has a low COD removal capacity, with a maximum of only 66.3%, and treats only a single characteristic pollutant.

[0006] EP1697264B1 discloses a method for treating polluted water using zeolite molecular sieves with different properties. This method mainly uses a combination of two types of zeolite molecular sieves to remove low and high concentrations of underground pollutants. Specifically, ZSM-5 and Y zeolite molecular sieves are used. However, this permeable reactive wall material is mainly based on adsorption, and the material cannot be used after adsorption saturation.

[0007] In summary, existing technologies offer limited options for adsorption-based materials, making them unsuitable for treating complex soil components and limiting their adsorption capacity. Traditional chemical oxidation materials exhibit limited resistance to concentration fluctuations, and seasonal variations in groundwater flow rates may result in insufficient treatment depth. Biodegradable materials suffer from poor versatility; varying site environments and diverse water components impact microbial survival, necessitating the cultivation of site-adapted microorganisms, which is time-consuming, and the generation of activated sludge during long-term use can clog the permeable reactive barrier. Therefore, it is necessary to develop a permeable reactive barrier material with superior treatment performance. Summary of the Invention

[0008] To address the problems existing in the prior art, this invention provides a permeable reactive wall filling material and its preparation method. The permeable reactive wall filling material of this invention comprises two molecular sieves with different silica-to-alumina ratios and metal oxides, effectively combining the principles of adsorption and oxidation. Applied to the treatment of soil and groundwater, it exhibits excellent treatment performance for low concentrations of organic pollutants in water and demonstrates superior regeneration capabilities.

[0009] In a first aspect, the present invention provides a permeable reactive wall filling material comprising a first molecular sieve, a second molecular sieve, a metal oxide, a mesoporous material, and a binder.

[0010] In some embodiments, the silica-to-alumina ratio of the first molecular sieve is greater than or equal to 200. In some embodiments, the silica-to-alumina ratio of the first molecular sieve is infinite, i.e., the first molecular sieve is an all-silica molecular sieve. In some embodiments, the silica-to-alumina ratio of the first molecular sieve is 200-1000.

[0011] In some embodiments, the silica-to-alumina ratio of the second molecular sieve is 5-90. In some embodiments, the silica-to-alumina ratio of the second molecular sieve is 7, 10, 13, 15, 17, 20, 23, 25, 27, 30, 33, 35, 37, 40, 43, 45, 47, 50, 53, 55, 57, 60, 63, 65, 67, 70, 73, 75, 77, 80, 83, 85, 87, or any value between them. In some embodiments, the silica-to-alumina ratio of the second molecular sieve is 15-50.

[0012] In some embodiments, the sodium content in the first molecular sieve is 0.01%-0.5% by mass, for example, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4% or 0.45%.

[0013] In some embodiments, the sodium content in the second molecular sieve is 0.01%-2% by mass, for example, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, or 1.9%.

[0014] In some embodiments, the mass content of the first molecular sieve is 5%-20% based on the mass of the permeable reactive wall filling material, for example, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% or 19%.

[0015] In some embodiments, the mass content of the second molecular sieve is 10%-30% based on the mass of the permeable reactive wall filling material. In some embodiments, the mass content of the second molecular sieve is 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 24.5%, 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, 28%, 28.5%, 29%, 29.5%, 30%, 31%, 32%, 33%, or any value between them, based on the mass of the permeable reactive wall filling material. In some embodiments, the mass content of the second molecular sieve is 20%-34% based on the mass of the permeable reactive wall filling material.

[0016] In some embodiments, the first molecule is selected from one or more of MFI-type molecular sieves and BEA-type molecular sieves.

[0017] In some embodiments, the second molecular sieve is selected from one or more of BEA-type molecular sieves, FAU-type molecular sieves, MWW-type molecular sieves, and MFI-type molecular sieves.

[0018] In some embodiments, the mass content of the metal oxide is 1%-10% based on the mass of the permeable reactive wall filling material. In some embodiments, the mass content of the metal oxide is 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 12%, 13%, 14%, or any value between these values, based on the mass of the permeable reactive wall filling material. In some embodiments, the mass content of the metal oxide is 2%-15% based on the mass of the permeable reactive wall filling material.

[0019] In some embodiments, the mass content of the mesoporous material is 5%-20% based on the mass of the permeable reactive wall filling material, for example, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% or 19%.

[0020] In some embodiments, the adhesive content is 20%-80% by mass, based on the mass of the permeable reactive wall filling material. In some embodiments, the adhesive content is 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or any value between them, based on the mass of the permeable reactive wall filling material.

[0021] In some embodiments, the metal oxide is selected from one or more iron oxides.

[0022] In some embodiments, the XRD pattern of the mesoporous material exhibits diffraction peaks in the range of 1°–3°. In some embodiments, the mesoporous material is selected from one or more of M41S molecular sieves and SBA-15 molecular sieves.

[0023] In some embodiments, the binder has a pore size distribution of 5 nm to 20 nm. In some embodiments, the binder is selected from one or more of boehmite, activated clay, diatomaceous earth, and montmorillonite.

[0024] In some embodiments, the total specific surface area of ​​the permeable reactive wall filling material is 150 m². 2 / g-500m 2 / g.

[0025] In some embodiments, the microporous specific surface area of ​​the permeable reactive wall filling material is 50%-90% of the total specific surface area.

[0026] In some embodiments, the total pore volume of the permeable reactive wall filling material is 0.1 mL / g to 0.6 mL / g.

[0027] In some embodiments, the mechanical strength of the permeable reactive wall filling material is 100 N / cm to 200 N / cm.

[0028] In a second aspect, the present invention provides a method for preparing a permeable reactive wall filling material, comprising:

[0029] S1: A mixture comprising a first molecular sieve, a second molecular sieve, a metal oxide precursor, a mesoporous material, a binder, and a pore-forming agent is subjected to molding treatment to obtain a shaped solid;

[0030] S2: The shaped solid is dried and calcined to obtain the permeable reactive wall filling material.

[0031] In some embodiments, the silica-to-alumina ratio of the first molecular sieve is greater than or equal to 200. In some embodiments, the silica-to-alumina ratio of the first molecular sieve is infinite, i.e., the first molecular sieve is an all-silica molecular sieve. In some embodiments, the silica-to-alumina ratio of the first molecular sieve is 200-1000.

[0032] In some embodiments, the silica-to-alumina ratio of the second molecular sieve is 5-90. In some embodiments, the silica-to-alumina ratio of the second molecular sieve is 7, 10, 13, 15, 17, 20, 23, 25, 27, 30, 33, 35, 37, 40, 43, 45, 47, 50, 53, 55, 57, 60, 63, 65, 67, 70, 73, 75, 77, 80, 83, 85, 87, or any value between them. In some embodiments, the silica-to-alumina ratio of the second molecular sieve is 5-50.

[0033] In some embodiments, the sodium content in the first molecular sieve is 0.01%-0.5% by mass, for example, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4% or 0.45%.

[0034] In some embodiments, the sodium content in the second molecular sieve is 0.01%-2% by mass, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, or 1.9%.

[0035] In some embodiments, the mass content of the first molecular sieve is 5%-20% based on the mass of the shaped solid, for example, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% or 19%.

[0036] In some embodiments, the mass content of the second molecular sieve is 10%-30% based on the mass of the molded solid. In some embodiments, the mass content of the second molecular sieve is 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 24.5%, 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, 28%, 28.5%, 29%, 29.5%, 30%, 31%, 32%, 33%, or any value between them, based on the mass of the molded solid. In some embodiments, the mass content of the second molecular sieve is 20%-34% based on the mass of the molded solid.

[0037] In some embodiments, the first molecule is selected from one or more of MFI-type molecular sieves and BEA-type molecular sieves.

[0038] In some embodiments, the second molecular sieve is selected from one or more of BEA-type molecular sieves, FAU-type molecular sieves, MWW-type molecular sieves, and MFI-type molecular sieves.

[0039] In some embodiments, the mass content of the metal oxide precursor is 1%-10% based on the mass of the molded solid. In some embodiments, the mass content of the metal oxide is 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 12%, 13%, 14%, or any value between these values, based on the mass of the molded solid. In some embodiments, the mass content of the metal oxide is 2%-15% based on the mass of the molded solid.

[0040] In some embodiments, the metal oxide precursor is selected from one or more iron salts. In some embodiments, the metal oxide precursor is selected from one or more of ferric nitrate, ferric sulfate, and ferrous sulfate.

[0041] In some embodiments, the mass content of the mesoporous material is 5%-20% based on the mass of the molded solid, for example, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% or 19%.

[0042] In some embodiments, the XRD pattern of the mesoporous material exhibits diffraction peaks in the range of 1°–3°. In some embodiments, the mesoporous material is selected from one or more of M41S molecular sieves and SBA-15 molecular sieves.

[0043] In some embodiments, the adhesive content is 20%-80% by mass, based on the mass of the molded solid. In some embodiments, the adhesive content is 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or any value between them, based on the mass of the molded solid.

[0044] In some embodiments, the binder has a pore size distribution of 5 nm to 20 nm. In some embodiments, the binder is selected from one or more of boehmite, activated clay, diatomaceous earth, and montmorillonite.

[0045] In some embodiments, the pore-forming agent has a mass content of 0.05%-2% based on the mass of the molded solid, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, or 1.9%.

[0046] In some embodiments, the pore-forming agent is selected from one or more of guar gum powder and cellulose.

[0047] In some embodiments, in S1, the molding process is selected from at least one of extrusion molding, ball forming, sheet forming, or spray forming.

[0048] In some embodiments, in step S2, the drying temperature is 50°C-120°C, for example, 60°C, 70°C, 80°C, 90°C, 100°C, or 110°C. In some embodiments, in step S2, the drying time is 2h-24h, for example, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, or 22h.

[0049] In some embodiments, in S2, the calcination temperature is 500°C-650°C, for example 530°C, 550°C, 570°C, 600°C or 630°C.

[0050] In a third aspect, the present invention provides the application of the permeable reactive wall filling material described in the first aspect or the permeable reactive wall filling material prepared by the preparation method described in the second aspect in water treatment.

[0051] In some embodiments, the organic pollutants in the soil groundwater (laboratory simulated contaminated groundwater) include toluene, ethylbenzene, phenol, MTBE, and gasoline, with a total organic carbon concentration of 30 mg / L to 300 mg / L.

[0052] In some embodiments, the water treatment is soil groundwater treatment. In some embodiments, the organic pollutants in the soil groundwater (actually polluted groundwater on site) include volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), total petroleum hydrocarbons (TPH) (C6-C9), and TPH (C6-C9). The VOCs include benzene, toluene, ethylbenzene, and xylene, and the semi-volatile organic compounds include benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthracene, benzo(k)fluoranthracene, and indo(1,2,3-cd)pyrene.

[0053] Compared with the prior art, the present invention has the following superior effects:

[0054] The permeable reactive wall filling material of this invention utilizes a first type of molecular sieve, namely a high-silica molecular sieve, which is hydrophobic and reduces competitive adsorption of water, thereby improving the material's treatment depth for organic matter in water. The second type of molecular sieve, in addition to adsorbing some organic pollutants, can also act as a solid acid, providing acid centers for the permeable reactive wall material. By combining molecular sieves of different pore sizes, the material exhibits a hierarchical pore distribution, expanding its application range and enhancing its adaptability. Loading with active metal oxides, combined with the acid centers of the material, allows for in-situ regeneration; after in-situ regeneration fails, ex-situ regeneration is possible. Using a material with a certain mesoporous distribution as a binder not only provides the material with a certain mechanical strength but also increases the specific surface area for the adsorption and retention of macromolecules. The permeable reactive wall filling material of this invention, when applied to the treatment of soil and groundwater, exhibits excellent treatment performance for low concentrations of organic pollutants in water and demonstrates superior regeneration capabilities. Attached Figure Description

[0055] Figure 1 The permeable reactive wall filling material of some embodiments of the present invention is shown. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention in any way. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of this disclosure. Such structures and techniques have also been described in many publications.

[0057] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0058] The present invention will be described in detail below through embodiments.

[0059] In this invention, the specific surface area and pore volume of the permeable reactive wall filling material are terms known in the art and can be tested using methods and instruments known in the art. Specifically, an ASAP2020M physicochemical adsorption instrument from Micron Instruments (USA) was used. Before measurement, the sample was evacuated and treated at 300°C for 2 hours to remove impurities adhering to the sample surface. Then, high-purity N2 was adsorbed at low temperature using liquid nitrogen to obtain the adsorption / desorption curve of the permeable reactive wall filling material. The specific surface area was calculated using the BET method, and the pore volume was calculated using the BJH method.

[0060] In this invention, the chemical composition of the sample, i.e. the silicon-to-aluminum ratio, was determined using an X-ray fluorescence spectrometer, specifically a Bruker S4 Pioneer instrument.

[0061] In this invention, the mechanical strength of the permeable reactive barrier filling material has a meaning known in the art and can be tested using methods and instruments known in the art. Specifically, the catalyst strength is determined using a DLⅢ type intelligent particle strength testing machine produced by Dalian Chemical Research and Design Institute. The measurement is performed 22 times, and the maximum and minimum values ​​are removed before taking the average value.

[0062] In this invention, the total organic carbon (TOC) of the sample was measured using Shimadzu TOC-L. CPH / CPN Total organic carbon analyzer.

[0063] In this invention, VOCs are analyzed using gas chromatography-mass spectrometry, and SVOCs are analyzed using high performance liquid chromatography and gas chromatography.

[0064] Example 1

[0065] Preparation of permeable reactive wall filling material:

[0066] The first molecular sieve, high-silica β molecular sieve powder (all silica), the second molecular sieve, ammonium-exchanged β molecular sieve powder (silicon-to-aluminum ratio 25), M41S mesoporous material powder, ferrous sulfate (calculated as ferric oxide by mass), attapulgite clay, and pore-forming agent guar gum powder are measured in a mass ratio of 10:20:10:5:30:0.1, mixed evenly, extruded into strips (3mm strips), dried, and calcined at 580℃.

[0067] Evaluation of the preparation of permeable reactive wall filling materials:

[0068] The evaluation was conducted using a fixed-bed column experiment. Permeable reactive material was packed into the reaction column. Aqueous contaminants and 8% hydrogen peroxide (mass concentration) were fed at a mass ratio of 20:1 in a bottom-in, top-out manner, with a total mass hourly space velocity (MHSV) of 1.5 h⁻¹. -1 The reaction is carried out under normal pressure and temperature conditions.

[0069] The soil and groundwater pollutants to be treated were prepared by mixing toluene, ethylbenzene, phenol, MTBE, gasoline, and benzo[a]anthracene with water in a mass ratio of 2:2:2:2:10:1 to form an aqueous solution with a TOC concentration of 150 mg / L.

[0070] The specific characterization and evaluation results are shown in Table 1.

[0071] Example 2

[0072] Unlike Example 1, the mass ratio of the first molecular sieve high-silica β molecular sieve powder, the second molecular sieve ammonium-exchanged β molecular sieve powder, M41S mesoporous material powder, ferrous sulfate (calculated as ferric oxide), attapulgite clay and pore-forming agent is 10:20:10:5:50:0.1. The characterization and evaluation results of this permeable reactive wall filling material are shown in Table 1.

[0073] Furthermore, the permeable reactive wall filling material prepared in this embodiment was used to evaluate the soil groundwater of a petrochemical site. Its initial TPH was 130 mg / L, and the TPH after treatment was 12 mg / L.

[0074] The permeable reactive barrier (PRB) filling material prepared in this embodiment was used to evaluate the soil groundwater at another petrochemical site. The initial TPH was 10 mg / L, the groundwater flow velocity was 50 m / year, and the PRB wall thickness was 0.6 m. After 180 days, the treated TPH was 0.5 mg / L, and benzene, toluene, ethylbenzene, xylene, and semi-volatile organic compounds (including benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthracene, benzo(k)fluoranthracene, indo(1,2,3-cd)pyrene, etc.) were not detected (lower limit of detection 10 mg / L). -6 (mg / L).

[0075] Example 3

[0076] Unlike Example 1, the mass ratio of the first molecular sieve high-silica β molecular sieve powder, the second molecular sieve ammonium-exchanged β molecular sieve powder, M41S mesoporous material powder, ferrous sulfate (calculated as ferric oxide), attapulgite clay and pore-forming agent is 10:20:10:5:100:0.1. The characterization and evaluation results of this permeable reactive wall filling material are shown in Table 1.

[0077] Examples 4 to 6

[0078] Unlike Example 1, the silicon-to-aluminum ratio of the second molecular sieve is 10, 50, and 75, respectively. The characterization and evaluation results of the permeable reactive wall filling material are shown in Table 1.

[0079] Example 7

[0080] Unlike Example 1, the mass ratio of the first molecular sieve high-silica β molecular sieve powder, the second molecular sieve ammonium-exchanged β molecular sieve powder, M41S mesoporous material powder, ferrous sulfate (calculated as ferric oxide), attapulgite clay and pore-forming agent is 10:22:10:3:30:0.1. The characterization and evaluation results of this permeable reactive wall filling material are shown in Table 1.

[0081] Example 8

[0082] Unlike Example 1, the mass ratio of the first molecular sieve high-silica β molecular sieve powder, the second molecular sieve ammonium-exchanged β molecular sieve powder, M41S mesoporous material powder, ferrous sulfate (calculated as ferric oxide), attapulgite and pore-forming agent is 10:24:10:1:30:0.1. The characterization and evaluation results of this permeable reactive wall filling material are shown in Table 1.

[0083] Example 9

[0084] Unlike Example 1, the mass ratio of the first molecular sieve high-silica β molecular sieve powder, the second molecular sieve ammonium-exchanged β molecular sieve powder, M41S mesoporous material powder, ferrous sulfate (calculated as ferric oxide), attapulgite and pore-forming agent is 10:18:10:7:30:0.1. The characterization and evaluation results of this permeable reactive wall filling material are shown in Table 1.

[0085] Example 10

[0086] Unlike Example 1, the mass ratio of the first molecular sieve high-silica β molecular sieve powder, the second molecular sieve ammonium-exchanged β molecular sieve powder, M41S mesoporous material powder, ferrous sulfate (calculated as ferric oxide), attapulgite clay and pore-forming agent is 10:15:10:10:30:0.1. The characterization and evaluation results of this permeable reactive wall filling material are shown in Table 1.

[0087] Comparative Example 1

[0088] The difference between Comparative Example 1 and Example 1 is that no first molecular sieve, high-silica β molecular sieve, is added. The characterization and evaluation results of the permeable reactive wall filling material are shown in Table 1.

[0089] Comparative Example 2

[0090] The difference between Comparative Example 2 and Example 1 is that the β molecular sieve after ammonium exchange of the second molecular sieve is not added. The characterization and evaluation results of the permeable reactive wall filling material are shown in Table 1.

[0091] Comparative Example 3

[0092] The difference between Comparative Example 3 and Example 1 is that no M41S mesoporous material was added. The characterization and evaluation results of the permeable reactive wall filling material are shown in Table 1.

[0093] Comparative Examples 4-5

[0094] The difference between Comparative Examples 4-5 and Example 1 is that the silicon-to-aluminum ratio of the second molecular sieve is 100 and 200, respectively. The characterization and evaluation results of the permeable reactive wall filling material are shown in Table 1.

[0095] Comparative Example 6

[0096] The difference between Comparative Example 6 and Example 1 is that the mass ratio of the first molecular sieve high-silica β molecular sieve powder, the second molecular sieve ammonium-exchanged β molecular sieve powder, M41S mesoporous material powder, ferrous sulfate (calculated as ferric oxide), attapulgite clay and pore-forming agent is 10:25:10:0:30:0.1, that is, no ferrous sulfate is added. The characterization and evaluation results of the permeable reactive wall filling material are shown in Table 1.

[0097] Comparative Example 7

[0098] The difference between Comparative Example 7 and Example 1 is that the mass ratio of the first molecular sieve high-silica β molecular sieve powder, the second molecular sieve ammonium-exchanged β molecular sieve powder, M41S mesoporous material powder, ferrous sulfate (calculated as ferric oxide), attapulgite clay and pore-forming agent is 10:0:10:25:30:0.1, that is, no second molecular sieve is added. The characterization and evaluation results of the permeable reactive wall filling material are shown in Table 1.

[0099] Table 1

[0100]

[0101] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A permeable reactive barrier packing material, comprising a first molecular sieve, a second molecular sieve, a metal oxide, a mesoporous material and a binder; the first molecular sieve has a silica-alumina ratio of greater than or equal to 200, and the second molecular sieve has a silica-alumina ratio of 5-90; the first molecular sieve has a mass content of 5%-20% based on the mass of the permeable reactive barrier packing material;and the second molecular sieve has a mass content of 10%-30% based on the mass of the permeable reactive barrier packing material; the metal oxide is selected from one or more of iron oxides; the mesoporous material has a XRD spectrum with a diffraction peak in the range of 1°-3°; the binder has a pore size distribution of 5 nm-20 nm; the mesoporous material is selected from one or both of M41S molecular sieve and SBA-15 molecular sieve.

2. The permeable reactive barrier filling material of claim 1, wherein, the first molecular sieve has a silica-alumina ratio of 200-1000;and / or the second molecular sieve has a silica-alumina ratio of 15-50.

3. The permeable reactive barrier filling material of claim 1, wherein, the first molecular sieve has a mass content of sodium element of 0.01%-0.5%.

4. The permeable reactive barrier filling material of claim 1, wherein, the second molecular sieve has a mass content of sodium element of 0.01%-2%.

5. The permeable reactive barrier filling material of claim 1, wherein, the first molecular sieve is selected from one or both of MFI type molecular sieve and BEA type molecular sieve;and / or the second molecular sieve is selected from one or more of BEA type molecular sieve, FAU type molecular sieve, MWW type molecular sieve and MFI type molecular sieve.

6. The permeable reactive barrier filling material according to any one of claims 1 to 5, characterized in that, the metal oxide has a mass content of 1%-10% based on the mass of the permeable reactive barrier packing material;and / or the mesoporous material has a mass content of 5%-20%;and / or the binder has a mass content of 20%-80%.

7. The permeable reactive barrier filling material of claim 1, wherein, the binder is selected from one or more of pseudo-boehmite, attapulgite, diatomite, montmorillonite and kaolin.

8. The permeable reactive barrier filling material of claim 1, wherein, The total specific surface area of the permeable reaction wall packing material is 150 m 2 / g-500 m 2 / g.

9. The permeable reactive barrier filling material of claim 1, wherein, the permeable reactive barrier packing material has a micropore specific surface area of 50%-90% of the total specific surface area;and / or the permeable reactive barrier packing material has a total pore volume of 0.1 mL / g-0.6 mL / g;and / or the permeable reactive barrier packing material has a mechanical strength of 100 N / cm-200 N / cm. 10.A method for preparing the permeable reactive barrier packing material according to any one of claims 1-9, comprising S1:forming a mixture comprising a first molecular sieve, a second molecular sieve, a metal oxide precursor, a binder, a pore-forming agent and a mesoporous material to obtain a formed solid; S2:drying and calcining the formed solid to obtain the permeable reactive barrier packing material.

11. The production method according to claim 10, characterized by, the first molecular sieve has a mass content of 5%-20% based on the mass of the formed solid, the second molecular sieve has a mass content of 10%-30% based on the mass of the formed solid, the metal oxide precursor has a mass content of 1%-10% based on the mass of the formed solid, the mesoporous material has a mass content of 5%-20% based on the mass of the formed solid, the binder has a mass content of 20%-80% based on the mass of the formed solid, and the pore-forming agent has a mass content of 0.05%-2% based on the mass of the formed solid.

12. The production method according to claim 10, characterized by, the pore-forming agent is selected from one or both of sesbania powder and cellulose;and / or the metal oxide precursor is selected from one or more of iron salts;and / or in S2, the drying temperature is 50℃-120℃, and / or the calcining temperature is 500℃-650℃.

13. The preparation method according to claim 10, characterized in that, The metal oxide precursor is selected from one or more of iron nitrate, iron sulfate, and ferrous sulfate.

14. Use of a permeable reactive barrier filling material according to any one of claims 1 to 9 or produced by the production process according to any one of claims 10 to 13 in water treatment.

15. Use of a permeable reactive barrier filling material according to any one of claims 1 to 9 or produced by the production process according to any one of claims 10 to 13 in soil and groundwater treatment.

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