Blocking material for risk management and control of polluted groundwater and preparation method therefor

Abstract

The present application relates to the technical field of groundwater pollution control. Specifically disclosed are a blocking material for risk management and control of polluted groundwater and a preparation method therefor. The blocking material for risk management and control of polluted groundwater provided by the present application comprises a powder material and a water material, wherein the powder material comprises the following components: 35-55% of bentonite, 15-30% of coal gangue, 5-15% of alkali-modified passion fruit shells, 20-40% of a modified adsorbent, and 0.5-1.5% of activated carbon fibers, the modified adsorbent being a medical stone adsorbent modified by water glass. The blocking material for risk management and control of polluted groundwater provided by the present application has a relatively large specific surface area and a dense pore structure. When being used for risk management and control of polluted groundwater, the blocking material facilitates multiple reactions of adsorption, ion exchange, filtration, precipitation, etc., with groundwater pollutants, and can block most pollutants; and the blocking material can exist in a severe groundwater environment for a long time without any change in performance, and has a sustainable blocking effect.

Description

A blocking material for controlling groundwater pollution risk and its preparation method

[0001] This patent application claims priority to Chinese patent application No. CN202311087681.5 filed on August 28, 2023. The disclosure of the prior application is incorporated herein by reference in its entirety. Technical Field

[0002] The present application relates to the technical field of groundwater pollution control, and specifically discloses a blocking material for controlling the risk of groundwater pollution and a preparation method thereof. Background Art

[0003] Groundwater is one of the most precious resources upon which human survival depends. In recent years, with the acceleration of urbanization and industrial restructuring in my country, soil and groundwater pollution caused by factors such as the relocation of industrial and mining enterprises, sudden environmental pollution incidents, and the illegal dumping or landfilling of pollutants and solid waste has posed a serious threat to my country's scarce groundwater resources. Industrial production sites are currently the most contaminated and complex sites in my country, with a wide range of contamination factors, such as wastewater discharge, solid waste sedimentation, pipeline leaks, and the transportation and storage of hazardous chemicals. These hazardous media contain large quantities of soil and groundwater. Compared to other types of site pollution, industrial production site pollution is characterized by high pollutant concentrations and wide spatial dispersion. These pollutants, including inorganic heavy metal pollution, organic chemical pollution, and their combination, severely contaminate the site's groundwater. Chemical wastewater discharge and leachate from industrial solid waste and sediment are the main causes of groundwater pollution. The large number of pollutants present in these areas, if not promptly addressed, can lead to a range of diseases and have a significant impact on human health.

[0004] At present, the main technologies for remediating groundwater pollution at industrial production sites include in-situ remediation technology, ex-situ remediation treatment technology, and monitored natural attenuation remediation technology. Among them, ex-situ remediation treatment technology and monitored natural attenuation remediation technology have greater limitations; while in-situ remediation technology focuses on the flow channels of groundwater and uses certain active prevention and control measures to block pollutants in situ. It has the advantages of high efficiency, convenience, low investment, and little disturbance to the surrounding environment. In-situ treatment methods have been developed for a relatively short time and mainly include source cleaning liquid technology, source gas oscillation technology, and origin reflection zone remediation technology. Source cleaning liquid technology is to immediately introduce the organic solvent of the cleaning liquid into the contaminated water quality, melt, transfer, and concentrate the pollutants in a unified area, extract the solution, and purify the groundwater body. It is not suitable for groundwater remediation at ex-situ remediation sites; source gas oscillation technology is only applicable to volatile pollutants; origin reflection zone remediation technology must be scientifically planned for groundwater pollution.

[0005] Traditional wastewater treatment methods cannot meet the needs of groundwater pollution control in industrial production sites, and specialized materials for groundwater pollution control are currently in short supply. Therefore, there is an urgent need to improve blocking materials used to prevent groundwater pollution. Through grouting, a pollutant blocking zone is formed behind the anti-seepage wall to achieve precise control of the contaminated site and efficient interception of pollutants, thereby ensuring the safety of groundwater resources. Technical issues

[0006] In response to the above problems, the present application provides a blocking material for controlling the risk of groundwater pollution and a preparation method thereof. The blocking material for controlling the risk of groundwater pollution has strong adsorption capacity and good environmental stability, and can exist for a long time in harsh groundwater environments and maintain unchanged performance. Technical Solutions

[0007] To solve the above technical problems, the technical solutions provided by this application are:

[0008] A blocking material for controlling groundwater pollution risks comprises a powder and a water material. The powder comprises the following components, calculated by weight percentage: 35% to 55% bentonite, 15% to 30% coal gangue, 5% to 15% alkali-modified passion fruit shell, 20% to 40% modified adsorbent, and 0.5% to 1.5% activated carbon fiber; the modified adsorbent is a medical stone adsorbent modified with water glass.

[0009] As an embodiment of the present application, the water material includes unpolluted surface water or groundwater.

[0010] As an embodiment of the present application, the mass ratio of the powder to the water is 1:(5~6).

[0011] Controlling the mass ratio of powder to water within the above range can ensure that the blocking material used for groundwater pollution risk control has a moderate consistency, meeting the pumping requirements while having a certain strength.

[0012] As an embodiment of the present application, the bentonite has a particle size of 5 to 12 μm.

[0013] As an embodiment of the present application, the particle size of the coal gangue is 10-15 mm.

[0014] As an embodiment of the present application, the preparation method of the alkali-modified passion fruit shell comprises the following steps: crushing the passion fruit shell to obtain passion fruit shell powder; adding the passion fruit shell powder to an alkaline solution, soaking at 80-100° C., washing, and drying to obtain alkali-modified passion fruit shell.

[0015] As an embodiment of the present application, the particle size of the passion fruit shell powder is 0.15~0.25mm.

[0016] As an embodiment of the present application, the alkaline solution is a 3-6 mol / L sodium hydroxide solution or a potassium hydroxide solution, and the volume mass ratio of the alkaline solution to the passion fruit shell powder is (10-15) mL:1 g; in the preparation method of the alkali-modified passion fruit shell, the immersion time is 2-5 h.

[0017] The present application immerses passion fruit shells in an alkaline solution to remove pigments and pectin from the passion fruit shells, thereby preventing the pigments and pectin from affecting the adsorption of anions in contaminated groundwater.

[0018] As an embodiment of the present application, the preparation method of the modified adsorbent includes the following steps: impregnating medical stone into water glass, and calcining the impregnated medical stone to obtain the modified adsorbent.

[0019] The medical stone of the present application has high adsorption capacity. The medical stone is immersed in water glass, which is composed of oligosilicic acid and high-polysilicic acid. The oligosilicic acid contains cage structures such as monosilicic acid, chain disilicate, chain trisilicic acid, cyclotetrasilicic acid, and cubic octasilicic acid. After the medical stone is immersed in water glass, a film composed of oligosilicic acid is formed inside the pores and on the surface of the medical stone. The cage-structured oligosilicic acids such as cyclotetrasilicic acid and cubic octasilicic acid change the pore structure of the medical stone, greatly increasing the adsorption capacity of the medical stone for pollutants in groundwater. After the immersed medical stone is calcined, the oligosilicic acid permanently resides in the pores of the medical stone through Si-O-Si or Si-O-Al connecting bonds, thereby obtaining a medical stone adsorbent with a larger adsorption capacity.

[0020] As an embodiment of the present application, the particle size of the medical stone is 50-90 μm, and the specific surface area is 200 m 2 / g or above, pore volume is 0.6m 3 / g or more, and the static water absorption rate is above 40%.

[0021] As an embodiment of the present application, the modulus of the water glass is 2.5~3, and the concentration is 2.5~3wt%.

[0022] The present application controls the modulus of water glass within the above range, which makes it easy to produce a pore structure of oligomers with a cubic structure and has a greater buffering effect on the acidity of the oligomeric silicic acid in the water glass.

[0023] As an embodiment of the present application, the solid-to-liquid ratio (mass-to-volume ratio) of the medical stone to the water glass is 1 g: (2.5-5) mL.

[0024] As an embodiment of the present application, in the preparation method of the modified adsorbent, the immersion temperature is 15-30° C. and the immersion time is 2.5-3 h.

[0025] The present application adopts an immersion method to allow water glass molecules to fully diffuse into the interior and surface of the medical stone to form a water glass film, which serves as a new pore structure of the medical stone and improves the adsorption capacity of the modified adsorbent.

[0026] As an embodiment of the present application, the calcination temperature is 400-550° C. and the calcination time is 2.5-5 hours.

[0027] In the preparation process of the modified adsorbent of the present application, oligosilicic acid is permanently retained in the pores of medical stone through Si-O-Si or Si-O-Al connecting bonds by calcination, thereby obtaining a medical stone adsorbent with a larger adsorption capacity.

[0028] As an embodiment of the present application, the average length of the activated carbon fiber is 90-120 μm, and the diameter of the single fiber is 0.5-2 μm.

[0029] For example, the activated carbon fibers are carbon fibers that have been activated at high temperature, and the carbon fibers can be at least one of phenolic-based fibers, polyacrylonitrile (PAN)-based fibers, viscose-based fibers, or asphalt-based fibers. This application does not limit the preparation method of the activated carbon fibers; as long as the activated carbon fibers have nanoscale pores, various commercially available activated carbon fibers may be used.

[0030] The activated carbon fiber surface of the present application has a nano-scale pore size, small volume, low filtration resistance, large specific surface area, and is acid-resistant, solvent-resistant, and has high mechanical strength. The activated carbon fiber is evenly dispersed between the components and forms a three-dimensional spatial network structure, which can play a good reinforcement role on the surrounding rock while treating pollutants; a certain amount of activated carbon fiber is configured in the blocking material for risk control of contaminated groundwater, so that the adsorption layer will not cause adsorption resistance due to the deposition of debris generated by adsorption, and will not cause powdering due to changes in the acid-base environment during adsorption regeneration, causing secondary pollution.

[0031] It is worth noting that in the powder of the blocking material for controlling the risk of contaminated groundwater provided in this application, each component has a particle size of different levels. The blocking material for controlling the risk of contaminated groundwater formed after the components in specific amounts are mixed evenly has moderate density, permeability and porosity, and can achieve multiple functions such as multi-level adsorption-ion exchange-filtration-precipitation, thereby achieving precise control of contaminated sites and efficient interception of pollutants, preventing the spread of deep-seated pollution sources in industrial production sites, and ensuring the safety of groundwater resources in industrial production sites.

[0032] The present application also provides a method for preparing a blocking material for controlling groundwater contamination risks, comprising the following steps:

[0033] S1, weighing each component according to the designed ratio, adding bentonite, coal gangue and alkali-modified passion fruit shell to the water material, and mixing them evenly to obtain a first mixture;

[0034] S2, adding modified adsorbent and activated carbon fiber to the first mixture in batches and mixing them evenly to obtain a second mixture;

[0035] S3, allowing the second mixture to stand and hydrate for 16 to 20 hours to obtain a blocking material for controlling the risk of groundwater pollution.

[0036] The present application also provides an application of a blocking material for controlling the risk of contaminated groundwater in the risk control of contaminated groundwater.

[0037] The blocking material for risk control of contaminated groundwater of the present application can be applied to risk control of contaminated groundwater in industrial production sites. The pollutants in the contaminated groundwater may include organic matter, heavy metal ions, dyes, sulfates, nitrates and other substances. Beneficial effects

[0038] Compared with the prior art, the bentonite in the blocking material for groundwater pollution risk control provided by the present application has excellent cation exchange capacity, and has certain buffering, attenuation and blocking capabilities for pollutants, and can be applied to extreme environments such as acidic and alkaline environments with high pollution loads; coal gangue is a solid waste discharged during the coal mining and coal washing processes. When used in the blocking material for groundwater pollution risk control, it can be used as a good filter filler to filter suspended matter in groundwater and save the amount of natural minerals; passion fruit shell has good adsorption performance for anions, and alkali-modified passion fruit shell can improve the adsorption effect of the blocking material for groundwater pollution risk control on anions in groundwater pollutants; after water glass modification The medical stone adsorbent has a large specific surface area and a dense pore structure, which greatly increases the reaction active sites between pollutants and materials, improves the capture capacity of active materials, and can achieve effective adsorption of various organic matter and heavy metal ions in contaminated groundwater; the surface of activated carbon fiber has nano-scale pores, small volume, small filtration resistance, large specific surface area, and is acid-resistant, solvent-resistant, and has high mechanical strength. A small amount of activated carbon fiber is dispersed in the blocking material for risk control of contaminated groundwater, which plays a great reinforcing role and can ensure that the blocking material for risk control of contaminated groundwater does not fall off under the action of strong water flow, greatly extending the service life of the blocking material for risk control of contaminated groundwater.

[0039] The blocking material used in this application for groundwater contamination risk control has a large specific surface area and a dense pore structure, which is conducive to multiple reactions such as adsorption-ion exchange-filtration-precipitation with groundwater pollutants, and can block most pollutants. It has good environmental stability and can exist for a long time in harsh groundwater environments (strong acid or strong alkali, various types of pollutants, dynamic water erosion, etc.) and maintain its performance unchanged, and its blocking effect is sustainable. In addition, coal gangue and passion fruit shells are industrial wastes. This application realizes the comprehensive utilization of industrial solid waste, which is more green and environmentally friendly, and the cost is greatly reduced. It has high practical value and promotion value.

[0040] The preparation method of the blocking material for controlling the risk of contaminated groundwater provided in the present application is simple to operate. During the static hydration process of the blocking material for controlling the risk of contaminated groundwater, the activated carbon fibers can be evenly dispersed therein and form a three-dimensional spatial network structure, thereby greatly improving the mechanical properties and scour resistance of the blocking material for controlling the risk of contaminated groundwater and extending its service life.

[0041] The blocking material for risk control of contaminated groundwater provided in this application is applied to the risk control of contaminated groundwater. Since the blocking material for risk control of contaminated groundwater has a large specific surface area and a dense pore structure, it can undergo multiple reactions such as adsorption-ion exchange-filtration-precipitation with groundwater pollutants, and can block most pollutants and form a pollutant blocking area behind the anti-seepage wall; at the same time, it has good environmental stability, can exist for a long time in harsh groundwater environments (strong acid or strong alkali, various types of pollutants, dynamic water erosion, etc.) and maintain unchanged performance, and the blocking effect is sustainable. Modes for Carrying Out the Invention

[0042] In the first aspect, the present application provides a blocking material for controlling the risk of groundwater pollution, including a powder and a water material. The powder includes the following components, calculated in percentage by mass: 35% to 55% bentonite, 15% to 30% coal gangue, 5% to 15% alkali-modified passion fruit shell, 20% to 40% modified adsorbent and 0.5% to 1.5% activated carbon fiber; the modified adsorbent is a medical stone adsorbent modified by water glass; the water material includes uncontaminated surface water or groundwater; the mass ratio of the powder to the water material is 1:(5~6).

[0043] The particle size of the bentonite is 5-12 μm; the particle size of the coal gangue is 10-15 mm; the particle size of the alkali-modified passion fruit shell is 0.15-0.25 mm; the particle size of the modified adsorbent is 50-120 μm; the average length of the activated carbon fiber is 90-120 μm, and the monofilament diameter is 0.5-2 μm.

[0044] In a second aspect, the present application provides a method for preparing a blocking material for controlling groundwater contamination risks, comprising the following steps:

[0045] S0, preparation of alkali-modified passion fruit shell and modified adsorbent, respectively;

[0046] The preparation method of the alkali-modified passion fruit shell comprises the following steps: crushing the passion fruit shell to obtain passion fruit shell powder; adding the passion fruit shell powder into an alkaline solution, soaking at 80-100° C., washing, and drying to obtain the alkali-modified passion fruit shell;

[0047] The particle size of the passion fruit shell powder is 0.15-0.25 mm; the alkaline solution is a 3-6 mol / L sodium hydroxide solution or a potassium hydroxide solution, and the volume mass ratio of the alkaline solution to the passion fruit shell powder is (10-15) mL:1 g; and the immersion time is 2-5 h.

[0048] The preparation method of the modified adsorbent comprises the following steps: impregnating medical stone into water glass, and calcining the impregnated medical stone to obtain the modified adsorbent;

[0049] The particle size of the medical stone is 50-90 μm, and the specific surface area is 200 m 2 / g or above, pore volume is 0.6m 3 / g or more, and a static water absorption rate of more than 40%; the modulus of the water glass is 2.5-3, and the concentration is 2.5-3wt%; the solid-liquid ratio of the medical stone to the water glass is 1g:(2.5-5)mL; the immersion temperature is 15-30°C, and the time is 2.5-3h; and the calcination temperature is 400-550°C, and the time is 2.5-5h.

[0050] S1, weighing each component according to the designed ratio, adding bentonite, coal gangue and alkali-modified passion fruit shell to the water material, and mixing them evenly to obtain a first mixture;

[0051] S2, adding modified adsorbent and activated carbon fiber to the first mixture in batches and mixing them evenly to obtain a second mixture;

[0052] S3, allowing the second mixture to stand and hydrate for 16 to 20 hours to obtain a blocking material for controlling the risk of groundwater pollution.

[0053] The mixing in steps S1 and S2 is performed under stirring at a stirring rate of 700-900 rpm.

[0054] On the third aspect, the present application also provides an application of a blocking material for controlling the risk of contaminated groundwater in the risk control of contaminated groundwater.

[0055] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0056] Example 1

[0057] This embodiment provides a blocking material for controlling the risk of groundwater contamination, comprising a powder and a water material, wherein the water material is uncontaminated surface water, and the mass ratio of the powder to the water material is 1:5.5. The powder is composed of the following components, in percentage by mass: 40% bentonite with a particle size of 10 μm, 20% coal gangue with a particle size of 12 mm, 10% alkali-modified passion fruit shell with a particle size of 0.2 mm, 29% modified adsorbent with a particle size of 80-90 μm, and 1% activated carbon fiber with an average length of 100 μm and a monofilament diameter of 0.5-2 μm.

[0058] The above-mentioned blocking material for controlling the risk of groundwater contamination is obtained by the following preparation method:

[0059] S01, preparing the alkali-modified passion fruit shell: crushing the passion fruit shell to obtain passion fruit shell powder with a particle size of 0.2 mm; adding the passion fruit shell powder to a 5 mol / L sodium hydroxide solution, immersing at 90° C. for 4 h, wherein the mass volume ratio of the passion fruit shell powder to the sodium hydroxide solution is 1 g:12 mL; washing, and drying to obtain the alkali-modified passion fruit shell;

[0060] S02, prepare the modified adsorbent: prepare a modified adsorbent having a particle size of 80 μm and a specific surface area of ​​200 m 2 / g or above, pore volume of 0.6m 3 / g or more and a static water absorption rate of more than 40% of medical stone is impregnated into a water glass with a modulus of 2.8 and a concentration of 2.8wt%, wherein the solid-liquid ratio of the medical stone to the water glass is 1g:4mL, and the mixture is impregnated at 20°C for 3h, and then the impregnated medical stone is calcined at 500°C for 4h to obtain a modified adsorbent with a particle size of 80-90μm;

[0061] S1, weighing each component according to the designed ratio, adding bentonite with different particle size grades, coal gangue and alkali-modified passion fruit shell to the water material, stirring for 25 minutes at a speed of 800 rpm to mix evenly, to obtain a first mixture;

[0062] S2, adding the modified adsorbent and activated carbon fiber to the first mixture in batches, stirring for 25 minutes to mix evenly, at a speed of 800 rpm, (for example, the modified adsorbent and activated carbon fiber are each divided into 2 equal parts, added in 2 times, stirring for 10 minutes after the first batch is added, and continuing to stir for 15 minutes after the second batch is added), to obtain a second mixture;

[0063] S3, allowing the second mixture to stand and hydrate for 18 hours to obtain a blocking material for controlling the risk of groundwater pollution.

[0064] The test results show that the average micropore size of the blocking material for groundwater contamination risk control is 142 nm, the porosity is 71.35%, and the permeability coefficient is 1.3×10 -7 cm / s (see Table 1).

[0065] Example 2

[0066] This embodiment provides a blocking material for controlling the risk of groundwater contamination, comprising a powder and a water material, wherein the water material is uncontaminated surface water, and the mass ratio of the powder to the water material is 1:5. The powder is composed of the following components, in percentage by mass: 35% bentonite with a particle size of 5 μm, 18.5% coal gangue with a particle size of 10 mm, 5% alkali-modified passion fruit shell with a particle size of 0.25 mm, 40% modified adsorbent with a particle size of 50-100 μm, and 1.5% activated carbon fiber with an average length of 90 μm and a monofilament diameter of 0.5-2 μm.

[0067] The above-mentioned blocking material for controlling the risk of groundwater contamination is obtained by the following preparation method:

[0068] S01, preparing the alkali-modified passion fruit shell: crushing the passion fruit shell to obtain passion fruit shell powder with a particle size of 0.25 mm; adding the passion fruit shell powder to a 6 mol / L sodium hydroxide solution, immersing at 80° C. for 5 h, wherein the ratio of the passion fruit shell powder to the sodium hydroxide solution is 1 g:10 mL; washing, and drying to obtain the alkali-modified passion fruit shell;

[0069] S02, prepare the modified adsorbent: prepare a modified adsorbent having a particle size of 50 μm and a specific surface area of ​​200 m 2 / g or above, pore volume of 0.6m 3 / g or more and a static water absorption rate of more than 40% is impregnated into a water glass with a modulus of 2.5 and a concentration of 2.5wt%, wherein the solid-liquid ratio of the medical stone to the water glass is 1g:5mL, and the mixture is impregnated at 15°C for 3h, and then the impregnated medical stone is calcined at 400°C for 5h to obtain a modified adsorbent with a particle size of 50-100μm;

[0070] S1, weighing each component according to the designed ratio, adding bentonite with different particle size grades, coal gangue and alkali-modified passion fruit shell to the water material, stirring for 20 minutes to mix evenly at a speed of 900 rpm to obtain a first mixture;

[0071] S2, adding the modified adsorbent and activated carbon fiber to the first mixture in batches, stirring for 20 minutes to mix evenly, at a speed of 900 rpm (for example, the modified adsorbent and activated carbon fiber are each divided into 2 equal parts and added in 2 times, stirring for 10 minutes after the first batch is added, and continuing to stir for 10 minutes after the second batch is added), to obtain a second mixture;

[0072] S3, allowing the second mixture to stand and hydrate for 16 hours to obtain a blocking material for controlling the risk of groundwater pollution.

[0073] The test results show that the average micropore size of the blocking material for groundwater contamination risk control is 150nm, the porosity is 72.62%, and the permeability coefficient is 1.4×10 -7 cm / s (see Table 1).

[0074] Example 3

[0075] This embodiment provides a blocking material for controlling the risk of groundwater contamination, comprising a powder and a water material, wherein the water material is uncontaminated surface water, and the mass ratio of the powder to the water material is 1:6. The powder is composed of the following components, in percentage by mass: 55% bentonite with a particle size of 9 μm, 15% coal gangue with a particle size of 15 mm, 8.5% alkali-modified passion fruit shell with a particle size of 0.25 mm, 20% modified adsorbent with a particle size of 50-100 μm, and 1.5% activated carbon fiber with an average length of 90 μm and a monofilament diameter of 0.5-2 μm.

[0076] The above-mentioned blocking material for controlling the risk of groundwater contamination is obtained by the following preparation method:

[0077] S01, preparing the alkali-modified passion fruit shell: crushing the passion fruit shell to obtain passion fruit shell powder with a particle size of 0.25 mm; adding the passion fruit shell powder to a 3 mol / L sodium hydroxide solution, immersing at 100° C. for 2 h, wherein the ratio of the passion fruit shell powder to the sodium hydroxide solution is 1 g:15 mL; washing, and drying to obtain the alkali-modified passion fruit shell;

[0078] S02, prepare the modified adsorbent: prepare a modified adsorbent having a particle size of 50 μm and a specific surface area of ​​200 m 2 / g or above, pore volume of 0.6m 3 / g or more and a static water absorption rate of more than 40% is impregnated into a water glass with a modulus of 2.5 and a concentration of 2.5wt%, wherein the solid-liquid ratio of the medical stone to the water glass is 1g:5mL, and the mixture is impregnated at 25°C for 3h, and then the impregnated medical stone is calcined at 400°C for 5h to obtain a modified adsorbent with a particle size of 50-100μm;

[0079] S1, weighing each component according to the designed ratio, adding bentonite with different particle size grades, coal gangue and alkali-modified passion fruit shell to the water material, stirring for 30 minutes at a speed of 700 rpm to mix evenly, to obtain a first mixture;

[0080] S2, adding the modified adsorbent and activated carbon fiber to the first mixture in batches, stirring for 30 minutes to mix evenly, at a speed of 700 rpm (for example, the modified adsorbent and activated carbon fiber are each divided into 2 equal parts and added in 2 times, stirring for 15 minutes after the first batch is added, and continuing to stir for 15 minutes after the second batch is added), to obtain a second mixture;

[0081] S3, allowing the second mixture to stand and hydrate for 20 hours to obtain a blocking material for controlling the risk of groundwater pollution.

[0082] The test results show that the average micropore size of the blocking material for groundwater contamination risk control is 134 nm, the porosity is 70.54%, and the permeability coefficient is 1.2×10 -7 cm / s (see Table 1).

[0083] Example 4

[0084] This embodiment provides a blocking material for controlling the risk of groundwater contamination, comprising a powder and a water material, wherein the water material is uncontaminated surface water, and the mass ratio of the powder to the water material is 1:5. The powder is composed of the following components, in percentage by mass: 35% bentonite with a particle size of 5 μm, 29.5% coal gangue with a particle size of 15 mm, 15% alkali-modified passion fruit shell with a particle size of 0.2 mm, 20% modified adsorbent with a particle size of 90-100 μm, and 0.5% activated carbon fiber with an average length of 120 μm and a monofilament diameter of 0.5-2 μm.

[0085] The above-mentioned blocking material for controlling the risk of groundwater contamination is obtained by the following preparation method:

[0086] S01, preparing the alkali-modified passion fruit shell: crushing the passion fruit shell to obtain passion fruit shell powder with a particle size of 0.2 mm; adding the passion fruit shell powder to a 5 mol / L potassium hydroxide solution, immersing at 90° C. for 4 h, wherein the ratio of the passion fruit shell powder to the potassium hydroxide solution is 1 g:12 mL; washing, and drying to obtain the alkali-modified passion fruit shell;

[0087] S02, prepare the modified adsorbent: prepare a modified adsorbent having a particle size of 90 μm and a specific surface area of ​​200 m 2 / g or above, pore volume of 0.6m 3 / g or more and a static water absorption rate of more than 40% of medical stone is impregnated into a water glass with a modulus of 3 and a concentration of 3wt%, wherein the solid-liquid ratio of the medical stone to the water glass is 1g:2.5mL, and the mixture is impregnated at 30°C for 2.5h, and then the impregnated medical stone is calcined at 550°C for 2.5h to obtain a modified adsorbent with a particle size of 90-100μm;

[0088] S1, weighing each component according to the designed ratio, adding bentonite with different particle size grades, coal gangue and alkali-modified passion fruit shell to the water material, stirring for 25 minutes at a speed of 800 rpm to mix evenly, to obtain a first mixture;

[0089] S2, adding the modified adsorbent and activated carbon fiber to the first mixture in batches, stirring for 25 minutes to mix evenly, at a speed of 800 rpm, (for example, the modified adsorbent and activated carbon fiber are each divided into 2 equal parts, added in 2 times, stirring for 10 minutes after the first batch is added, and continuing to stir for 15 minutes after the second batch is added), to obtain a second mixture;

[0090] S3, allowing the second mixture to stand and hydrate for 18 hours to obtain a blocking material for controlling the risk of groundwater pollution.

[0091] The test results show that the average micropore size of the blocking material for groundwater contamination risk control is 131 nm, the porosity is 70.01%, and the permeability coefficient is 1.1×10 -7 cm / s (see Table 1).

[0092] Comparative Example 1

[0093] This comparative example provides a blocking material for controlling the risk of groundwater pollution. The specific components are similar to those in Example 1, except that the modified adsorbent is replaced with kaolin of equal mass content.

[0094] The specific preparation steps of the above-mentioned blocking material for controlling the risk of contaminated groundwater are the same as those in Example 1, except that the preparation of the modified adsorbent is omitted and the modified adsorbent is replaced by kaolin with an equal mass content.

[0095] The test results show that the average micropore size of the blocking material for groundwater contamination risk control is 30 nm, the porosity is 65.21%, and the permeability coefficient is 0.53×10 -7 cm / s (see Table 1).

[0096] Comparative Example 2

[0097] This comparative example provides a blocking material for controlling the risk of groundwater pollution. The specific components are similar to those of Example 1, except that it does not contain activated carbon fiber and the content of the modified adsorbent is 30%.

[0098] The specific preparation steps of the above-mentioned blocking material for controlling the risk of contaminated groundwater are the same as those in Example 1, except that no activated carbon fiber is added.

[0099] The test results show that the average micropore size of the blocking material for groundwater contamination risk control is 82 nm, the porosity is 69.24%, and the permeability coefficient is 0.68×10 -7 cm / s (see Table 1).

[0100] Performance Testing

[0101] Compressive strength determination: Standard specimens of Φ50 mm × 100 mm were prepared using the blocking materials for risk control of contaminated groundwater according to Examples 1 to 4 and Comparative Examples 1 to 2. The strength of the standard specimens when compressed to deformation was measured using a pressure testing machine. To ensure accuracy, the average value of three standard specimens in the same group was taken. Specific compressive strength data are shown in Table 1.

[0102] Table 1 Performance of blocking materials for controlling groundwater pollution risks in Examples 1 to 4 and Comparative Examples 1 to 2

[0103]

[0104] It can be seen from the above table that the blocking material for groundwater pollution risk control in the embodiment of the present application has a good permeability coefficient, and the water permeability of the blocking material for groundwater pollution risk control can greatly reduce the interference of grouting on the groundwater flow field; the modified adsorbent and activated carbon fiber in the present application can significantly improve the porosity and permeability parameters of the blocking material for groundwater pollution risk control; the activated carbon fiber in the present application can significantly improve the compressive strength of the blocking material for groundwater pollution risk control.

[0105] Pollutant removal test of contaminated groundwater in simulated industrial production sites

[0106] The pollutant content of the contaminated groundwater in the simulated industrial production site is shown in Table 2, and a dynamic adsorption column test of the blocking material for the risk control of contaminated groundwater is conducted. The adsorption column is a plexiglass column with a length of 100 cm and an inner diameter of 4 cm. The plexiglass column contains 30 cm high river sand as a filling medium. The blocking materials for the risk control of contaminated groundwater in Examples 1 to 4 and Comparative Examples 1 to 2 are used as active media and are evenly filled in the plexiglass column. The filling height is 60 cm. Contaminated groundwater in the simulated industrial production site is added to the adsorption column at a speed of 5 mL / min by a peristaltic pump, and the concentration of each ion in the outlet is monitored every 30 minutes. The test results show that after 4 hours of the test, the adsorption capacity of the blocking material for the risk control of contaminated groundwater for the five ions reaches equilibrium. The specific test data are shown in Table 3.

[0107] Table 2 Pollutant content of contaminated groundwater in simulated industrial production sites

[0108]

[0109] Table 3 Pollutant removal rate (%) of blocking materials for controlling groundwater contamination risk in Examples 1-4 and Comparative Examples 1-2

[0110]

[0111] It can be seen from the above table that the blocking material for risk control of contaminated groundwater provided in this application can effectively remove pollutants in contaminated groundwater in simulated industrial production sites.

[0112] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A blocking material for risk control of groundwater pollution, characterized in that: The invention comprises powder and water, wherein the powder comprises the following components in percentage by mass: 35% to 55% of bentonite, 15% to 30% of coal gangue, 5% to 15% of alkali-modified passion fruit shell, 20% to 40% of modified adsorbent and 0.5% to 1.5% of activated carbon fiber; the modified adsorbent is medical stone adsorbent modified by water glass.

2. The blocking material for controlling the risk of contaminated groundwater according to claim 1, characterized in that: The water material includes uncontaminated surface water or groundwater; and / or The mass ratio of the powder to the water is 1:(5-6).

3. The blocking material for controlling the risk of contaminated groundwater according to claim 1, characterized in that: The particle size of the bentonite is 5 to 12 μm; and / or The particle size of the coal gangue is 10-15 mm; and / or The average length of the activated carbon fiber is 90-120 μm, and the diameter of the single fiber is 0.5-2 μm.

4. The blocking material for controlling the risk of contaminated groundwater according to claim 1, characterized in that: The preparation method of the alkali-modified passion fruit shell comprises the following steps: Grinding passion fruit shell to obtain passion fruit shell powder; The passion fruit shell powder is added into an alkaline solution, immersed at 80-100° C., washed and dried to obtain an alkali-modified passion fruit shell.

5. The blocking material for controlling the risk of groundwater contamination according to claim 4, characterized in that: The particle size of the passion fruit shell powder is 0.15-0.25 mm; and / or The alkaline solution is a 3-6 mol / L sodium hydroxide solution or a potassium hydroxide solution, and the volume mass ratio of the alkaline solution to the passion fruit shell powder is (10-15) mL:1 g; and / or In the preparation method of the alkali-modified passion fruit shell, the immersion time is 2 to 5 hours.

6. The blocking material for controlling the risk of contaminated groundwater according to claim 1, characterized in that: The preparation method of the modified adsorbent comprises the following steps: The medical stone is immersed in water glass, and the immersed medical stone is calcined to obtain a modified adsorbent.

7. The blocking material for controlling the risk of groundwater contamination according to claim 6, characterized in that: The particle size of the medical stone is 50-90 μm, and the specific surface area is 200 m 2 / g or more, pore volume is 0.6m 3 / g or more, static water absorption rate is more than 40%; and / or The modulus of the water glass is 2.5-3, and the concentration is 2.5wt%-3wt%; and / or The solid-to-liquid ratio of the medical stone to the water glass is 1g:(2.5-5)mL.

8. The blocking material for controlling the risk of groundwater contamination according to claim 6, characterized in that: In the preparation method of the modified adsorbent, the immersion temperature is 15-30° C. and the immersion time is 2.5-3 h; and / or The calcination temperature is 400~550℃ and the time is 2.5~5h.

9. The method for preparing the blocking material for controlling the risk of contaminated groundwater according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, weighing each component according to the designed ratio, adding bentonite, coal gangue and alkali-modified passion fruit shell into the water material, mixing evenly, to obtain a first mixed material; S2, adding modified adsorbent and activated carbon fiber to the first mixture in batches, mixing evenly, to obtain a second mixture; S3, allowing the second mixture to stand and be hydrated for 16 to 20 hours to obtain a blocking material for controlling the risk of groundwater pollution.

10. Use of the blocking material for risk control of contaminated groundwater according to any one of claims 1 to 8 in risk control of contaminated groundwater.

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