An impermeable bentonite waterproof blanket and its preparation method

Abstract

The present invention discloses an impermeable bentonite waterproof blanket and a preparation method thereof, belonging to the technical field of waterproof blankets. It includes a woven fabric and a geotextile. A composite superabsorbent material is arranged between the woven fabric and the geotextile. By weight, the composite superabsorbent material includes 100 parts of modified bentonite and 2 - 8 parts of acrylic acid superabsorbent resin. The preparation method of this waterproof blanket includes the following steps: mixing the modified bentonite and the acrylic acid superabsorbent resin, evenly spreading them on the woven fabric, laying the geotextile, and using the needle punching method to fix the composite superabsorbent material between the woven fabric and the geotextile, thus obtaining the impermeable bentonite waterproof blanket. The present invention uses modified bentonite and acrylic acid superabsorbent resin to prepare the composite superabsorbent material, enabling the waterproof blanket to still maintain excellent impermeable performance even in the harsh environment of saline sewage, broadening its application scope. At the same time, the waterproof blanket also has a significant adsorption capacity for harmful substances such as hexavalent chromium ions in sewage, promoting the process of environmental protection and ecological restoration.

Description

Technical Field

[0001] The present invention belongs to the technical field of waterproof blankets, and particularly relates to an impermeable bentonite waterproof blanket and a preparation method thereof. Background Technique

[0002] A bentonite waterproof blanket (Geosynthetic Clay Liners, GCL) is a composite waterproof material in which bentonite particles are evenly laid between two geotextiles according to certain quality requirements and made into a material with tiny voids through processes such as needling. The geotextiles mainly play a protective role. The bentonite waterproof blanket mainly utilizes the principle of bentonite swelling when encountering water. The sodium-based bentonite selected in the waterproof blanket can swell at least dozens of times when encountering water. Relying on the needle-punched fibers, the bentonite layer is locked between two geotextiles to form a uniform and dense colloid system with high viscosity and a very small hydraulic permeability coefficient, which can effectively prevent water.

[0003] The bentonite waterproof blanket not only has excellent properties of geotechnical materials but also has excellent waterproof and anti-seepage performance. Compared with a compacted clay liner, it has the advantages of small volume, good flexibility, good sealing performance, high shear strength, simple construction, and adaptability to uneven settlement. It is mainly applied to projects such as landfills, tailings ponds, hazardous waste dumps, artificial lakes, landscape water systems, and underground infrastructure construction in environmental engineering to solve problems such as sealing, isolation, and anti-seepage, with good effects and strong anti-destructive ability.

[0004] However, in saline sewage, due to ion exchange, the molecular structure of bentonite will be damaged, or the particles cannot bond together, resulting in a significant reduction in viscosity, and the anti-seepage performance of the bentonite waterproof blanket decreases. Summary of the Invention

[0005] The purpose of the present invention is to provide an impermeable bentonite waterproof blanket and a preparation method thereof to solve the problem of poor anti-seepage performance of existing bentonite waterproof blankets in saline sewage.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] An impermeable bentonite waterproof blanket includes a woven fabric and a geotextile. A composite superabsorbent material is provided between the woven fabric and the geotextile. By weight, the composite superabsorbent material includes 100 parts of modified bentonite and 2 - 8 parts of acrylic acid superabsorbent resin.

[0008] The present invention prepares a composite superabsorbent material from modified bentonite and acrylic acid superabsorbent resin. There are a large number of molecular chains carrying positive charges on the surface of the modified bentonite, and a large number of molecular chains carrying negative charges on the surface of the acrylic acid superabsorbent resin. When encountering water, while the modified bentonite and the acrylic acid superabsorbent resin absorb water and swell, due to the mutual attraction of the positive and negative charge molecular chains, the modified bentonite and the acrylic acid superabsorbent resin crosslink into a three-dimensional network structure in water, improving the density of the internal system of the waterproof blanket, reducing the seepage channels, and promoting a significant improvement in the anti-seepage performance compared with ordinary bentonite waterproof blankets.

[0009] Further, the modified bentonite is prepared through the following steps:

[0010] Add acrylamide to deionized water, stir and react for 20 - 30 min, then add sodium-based bentonite, stir for 10 - 20 min and then perform ultrasonic treatment for 30 - 60 min, add N,N'-methylenebisacrylamide, quaternized polyethyleneimine and potassium persulfate, react at 70 - 80 °C for 2 - 2.5 h, naturally cool to room temperature and then transfer to an oven to dry to constant weight at 80 - 100 °C, and finally pulverize and pass through a 40-mesh sieve to obtain the modified bentonite.

[0011] Using acrylamide as the polymerization monomer, N,N'-methylenebisacrylamide as the crosslinking agent, quaternized polyethyleneimine as the additive, and potassium persulfate as the initiator, a superabsorbent polymer is introduced onto the surface of sodium-based bentonite through a polymerization reaction to obtain modified bentonite. Compared with sodium-based bentonite, the tight combination between the superabsorbent polymer and sodium-based bentonite blocks the cation exchange inside the bentonite to a certain extent, enhancing the anti-salt performance of the bentonite material. A large number of hydrophilic groups such as amino groups and quaternary ammonium salt structures are introduced on the surface of the modified bentonite, which can combine both the cation hydration swelling and the swelling of hydrophilic functional groups to further improve the swelling performance of the modified bentonite. In addition, the introduction of the quaternary ammonium salt structure can also improve the adsorption performance of sodium-based bentonite for hexavalent chromium ions in sewage, which is beneficial to expanding the application of bentonite waterproof blankets in chromium (VI)-containing wastewater.

[0012] Further, the dosage ratio of deionized water, acrylamide, sodium-based bentonite, N,N'-methylenebisacrylamide, quaternized polyethyleneimine and potassium persulfate is 200 - 300 mL : 15.06 - 16.86 g : 45 g : 0.05 g : 4.5 - 5.0 g : 0.3 - 0.4 g.

[0013] Further, the quaternized polyethyleneimine is prepared through the following steps:

[0014] Add branched polyethyleneimine into a flask containing absolute ethanol, add allyl chloride, and react at 80 °C for 24 h. After the reaction, rotary evaporate to remove absolute ethanol at 60 - 80 °C, and place the rotary evaporation product in a vacuum oven to dry at 80 °C for 24 h; the mass ratio of branched polyethyleneimine to allyl chloride is 8:1.4 - 2.1, the Mw of hyperbranched polyethyleneimine is 800, using branched polyethyleneimine containing high-density amino groups as the raw material and allyl chloride as the quaternization reagent, through the quaternization reaction, quaternized polyethyleneimine is obtained.

[0015] Further, the acrylic acid water-absorbing resin is prepared through the following steps:

[0016] Mix acrylic acid, sodium carboxymethylcellulose, and deionized water evenly, add N,N'-methylenebisacrylamide and N-allyl-N'-(sodium sulfanilate)thiourea, dropwise add potassium persulfate solution at 60 °C. After the dropping is completed, raise the temperature to 70 °C and react for 2 - 3 h, then transfer to an oven to dry at 80 - 100 °C to constant weight, and finally crush and pass through a 40-mesh sieve to obtain the acrylic acid water-absorbing resin.

[0017] Further, the mass ratio of acrylic acid, sodium carboxymethylcellulose, deionized water, N,N'-methylenebisacrylamide, N-allyl-N'-(sodium sulfanilate)thiourea, and potassium persulfate solution is 20 g:2.6 g:19 - 20 mL:0.04 g:2.5 - 4.5 g:10 mL, and the potassium persulfate solution is composed of potassium persulfate and deionized water according to the dosage ratio of 0.4 g:10 mL.

[0018] Further, the woven fabric is a polypropylene woven fabric or a polyethylene woven fabric.

[0019] Further, the geotextile is a non-woven geotextile, the fiber web of the non-woven geotextile is polyester or polypropylene fiber, and the unit area mass is 220 g / m 2 。

[0020] The preparation method of the above impermeable bentonite waterproof blanket includes the following steps:

[0021] Add the modified bentonite and the acrylic acid water-absorbing resin into a stirring tank, stir and mix at 300 - 500 rpm for 30 - 60 min to obtain a composite high water-absorbing material; evenly spread the composite high water-absorbing material on the woven fabric, then lay the geotextile, and use the needling method to fix the composite high water-absorbing material between the woven fabric and the geotextile to obtain the impermeable bentonite waterproof blanket.

[0022] The beneficial effects of the present invention:

[0023] 1. The present invention provides an impermeable bentonite waterproof blanket, which prepares a composite superabsorbent material from modified bentonite and acrylic acid superabsorbent resin, enabling the waterproof blanket to maintain excellent impermeable performance even in a harsh environment of saline sewage, effectively ensuring the stability and reliability of the waterproof layer, thereby greatly expanding the application range of the bentonite waterproof blanket under diverse, complex geological and hydrological conditions. At the same time, the waterproof blanket also has a significant adsorption capacity for harmful substances such as hexavalent chromium ions in sewage, further promoting the process of environmental protection and ecological restoration.

[0024] 2. By modifying sodium-based bentonite, the present invention significantly improves the swelling performance and salt tolerance compared to sodium-based bentonite. In addition, it also has good adsorption performance for hexavalent chromium ions in sewage.

[0025] 3. Using carboxymethyl cellulose and N-allyl-N'-(sodium sulfonate aminobenzene) thiourea as additives, and acrylic acid as the raw material, the acrylic acid superabsorbent resin obtained by aqueous solution polymerization not only has high water absorption and water retention performance, but also has enhanced salt tolerance due to the sulfonate groups carried by N-allyl-N'-(sodium sulfonate aminobenzene) thiourea. In addition, N-allyl-N'-(sodium sulfonate aminobenzene) thiourea also carries thiourea groups, and the thiourea groups have a good complexing effect on heavy metal ions and also have good adsorption performance for hexavalent chromium ions in sewage. Detailed implementation mode

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0027] The sources of some materials in the following embodiments and comparative examples are as follows:

[0028] Branched polyethyleneimine (PEI, M W = 800), 99%, Shanghai Macklin Biochemical Technology Co., Ltd.;

[0029] Sodium-based bentonite, montmorillonite content > 70%, cation exchange capacity of 83.69 cmol / kg, purchased from Liancheng County Henghe Bentonite Co., Ltd.;

[0030] Sodium carboxymethyl cellulose, purchased from Guangzhou Yuanda New Materials Co., Ltd., purity ≥ 99%;

[0031] N-allyl-N'-(sodium sulfanilate) thiourea and its preparation method belong to the prior art. For example, "A New Method for the Phase-Transfer Catalyzed Synthesis of N-allyl-N'-(sodium sulfanilate) thiourea", by Ma Donglan, Wang Yulan, Ding Guosheng, Li Jianping.

[0032] Example 1

[0033] This example provides a modified bentonite, which is prepared through the following steps:

[0034] Add 15.06 g of acrylamide to 200 mL of deionized water, stir and react for 20 min. Then add 45 g of sodium-based bentonite, stir for 10 min and then perform ultrasonic treatment for 30 min. Add 0.05 g of N,N'-methylenebisacrylamide, 4.5 g of quaternized polyethyleneimine and 0.3 g of potassium persulfate, and react at 70 °C for 2 h. After natural cooling to room temperature, transfer it to an oven and dry it at 80 °C to constant weight. Finally, crush it through a 40-mesh sieve to obtain the modified bentonite.

[0035] Quaternized polyethyleneimine is prepared through the following steps:

[0036] Add 8 g of branched polyethyleneimine to a flask containing 80 mL of absolute ethanol, add 1.4 g of allyl chloride, and react at 80 °C for 24 h. After the reaction is completed, rotary evaporate to remove absolute ethanol at 60 °C. Place the rotary evaporation product in a vacuum oven and dry it at 80 °C for 24 h.

[0037] Example 2

[0038] This example provides a modified bentonite, which is prepared through the following steps:

[0039] Add 16.86 g of acrylamide to 300 mL of deionized water, stir and react for 30 min. Then add 45 g of sodium-based bentonite, stir for 20 min and then perform ultrasonic treatment for 60 min. Add 0.05 g of N,N'-methylenebisacrylamide, 5.0 g of quaternized polyethyleneimine and 0.4 g of potassium persulfate, and react at 80 °C for 2.5 h. After natural cooling to room temperature, transfer it to an oven and dry it at 100 °C to constant weight. Finally, crush it through a 40-mesh sieve to obtain the modified bentonite.

[0040] Quaternized polyethyleneimine is prepared through the following steps:

[0041] Add 8 g of branched polyethyleneimine to a flask containing 100 mL of absolute ethanol, add 2.1 g of allyl chloride, and react at 80 °C for 24 h. After the reaction is completed, rotary evaporate to remove absolute ethanol at 80 °C. Place the rotary evaporation product in a vacuum oven and dry it at 80 °C for 24 h.

[0042] Comparative Example 1

[0043] This comparative example provides a modified bentonite. On the basis of Example 1, the quaternized polyethyleneimine in Example 1 is removed, and the remaining raw materials, parameters and preparation process are the same as those in Example 1.

[0044] Comparative Example 2

[0045] This comparative example is sodium-based bentonite.

[0046] The bentonites provided in Examples 1-2 and Comparative Examples 1-2 are tested. The expansibility is carried out according to the "Industry Standard for Sodium-based Bentonite Waterproof Blanket JG / T 193-2006", and the steps are as follows:

[0047] 1) Sieve the specimens through a 200-mesh sieve and dry them at 105 °C for 48 h until constant weight;

[0048] 2) Add 90 mL of deionized water to a 100-mL graduated cylinder, and accurately weigh the specimen (2.00 ± 0.01) g. Add 0.1 g of the specimen to cover the water surface in the graduated cylinder within 30 s each time. Wait until the previously added soil sample has completely sunk to the bottom of the graduated cylinder before the next addition;

[0049] 3) After all the specimens are added, use deionized water to rinse the soil sample attached to the inner wall of the graduated cylinder, and add deionized water to 100 mL;

[0050] 4) Let the sample stand for 24 h and then read the volume of the soil sample in the graduated cylinder. During the reading process, the low-density flocs attached to the upper layer should be ignored, and the swelling index m is calculated based on the top of the soil mass F , and the results are shown in Table 1;

[0051] The salt tolerance is evaluated by the swelling performance of the specimen in solutions of different ion types. The test method refers to the above-mentioned expansibility test, and deionized water is replaced with NaCl solution with a concentration of 20 mmol / L and CaCl solution with a concentration of 20 mmol / L 2 solution, and the swelling index m F ; the results are shown in Table 1;

[0052] Table 1

[0053]

[0054] It can be seen from the data recorded in Table 1 that the swelling performance of the modified bentonites in Examples 1-2 and Comparative Example 1 is greatly improved compared with the original sodium-based bentonite soil in Comparative Example 2, and Examples 1-2 are significantly better than Comparative Example 1.

[0055] Example 3

[0056] An anti-seepage bentonite waterproof blanket, comprising a woven fabric and a geotextile, wherein a composite superabsorbent material is provided between the woven fabric and the geotextile. By weight, the composite superabsorbent material comprises 100 parts of the modified bentonite of Example 1 and 2 parts of an acrylic acid superabsorbent resin.

[0057] The acrylic acid superabsorbent resin is prepared by the following steps:

[0058] 20 g of acrylic acid, 2.6 g of sodium carboxymethyl cellulose and 19 mL of deionized water are stirred and mixed for 30 min, 0.04 g of N,N'-methylenebisacrylamide and 2.5 g of N-allyl-N'-(sodium sulfanilate) thiourea are added, 10 mL of a potassium persulfate solution is added dropwise at 60 °C. After the addition is completed, the temperature is raised to 70 °C and the reaction is carried out for 2 h. Then it is transferred to an oven and dried to constant weight at 80 °C, and finally pulverized and sieved through a 40-mesh sieve to obtain the acrylic acid superabsorbent resin. The potassium persulfate solution is composed of potassium persulfate and deionized water according to a dosage ratio of 0.4 g:10 mL.

[0059] The woven fabric is a polypropylene woven fabric.

[0060] The geotextile is a non-woven geotextile. The fiber web of the non-woven geotextile is polyester, and the unit area mass is 220 g / m 2 .

[0061] The preparation method of the above anti-seepage bentonite waterproof blanket comprises the following steps:

[0062] The modified bentonite and the acrylic acid superabsorbent resin are added to a stirring tank and stirred and mixed at 300 rpm for 30 min to obtain a composite superabsorbent material; the composite superabsorbent material is evenly spread on the woven fabric, and then the geotextile is laid. The composite superabsorbent material is fixed between the woven fabric and the geotextile by a needling method, and an anti-seepage bentonite waterproof blanket with a thickness of 3 mm and a unit area mass of 4000 g / m 2 is obtained.

[0063] Example 4

[0064] An anti-seepage bentonite waterproof blanket, comprising a woven fabric and a geotextile, wherein a composite superabsorbent material is provided between the woven fabric and the geotextile. By weight, the composite superabsorbent material comprises 100 parts of the modified bentonite of Example 2 and 5 parts of an acrylic acid superabsorbent resin.

[0065] The acrylic acid superabsorbent resin is prepared by the following steps:

[0066] 20 g of acrylic acid, 2.6 g of sodium carboxymethyl cellulose and 19 mL of deionized water were stirred and mixed for 40 min. Then, 0.04 g of N,N’-methylenebisacrylamide and 3.2 g of N-allyl-N’-(sodium sulfanilate) thiourea were added. At 60 °C, 10 mL of potassium persulfate solution was added dropwise. After the addition was complete, the temperature was raised to 70 °C and the reaction was carried out for 2.5 h. Then, it was transferred to an oven and dried at 90 °C to constant weight. Finally, it was crushed and passed through a 40-mesh sieve to obtain acrylic acid water-absorbing resin. The potassium persulfate solution was composed of potassium persulfate and deionized water according to the dosage ratio of 0.4 g:10 mL.

[0067] The woven fabric is a polyethylene woven fabric.

[0068] The geotextile is a non-woven geotextile. The fiber web of the non-woven geotextile is polypropylene fiber, and the unit area mass is 220 g / m 2 。

[0069] The preparation method of the above anti-seepage bentonite waterproof blanket includes the following steps:

[0070] The modified bentonite and acrylic acid water-absorbing resin were added to a stirring tank and stirred and mixed at 500 rpm for 60 min to obtain a composite superabsorbent material. The composite superabsorbent material was evenly spread on the woven fabric, and then the geotextile was laid. The composite superabsorbent material was fixed between the woven fabric and the geotextile by the needle punching method, and an anti-seepage bentonite waterproof blanket with a thickness of 3 mm and a unit area mass of 4000 g / m 2 was obtained.

[0071] Example 5

[0072] An anti-seepage bentonite waterproof blanket includes a woven fabric and a geotextile. A composite superabsorbent material is arranged between the woven fabric and the geotextile. By weight, the composite superabsorbent material includes 100 parts of the modified bentonite in Example 2 and 8 parts of acrylic acid water-absorbing resin.

[0073] The acrylic acid water-absorbing resin was made through the following steps:

[0074] 20 g of acrylic acid, 2.6 g of sodium carboxymethyl cellulose and 20 mL of deionized water were stirred and mixed for 60 min. Then, 0.04 g of N,N’-methylenebisacrylamide and 4.5 g of N-allyl-N’-(sodium sulfanilate) thiourea were added. At 60 °C, 10 mL of potassium persulfate solution was added dropwise. After the addition was complete, the temperature was raised to 70 °C and the reaction was carried out for 3 h. Then, it was transferred to an oven and dried at 100 °C to constant weight. Finally, it was crushed and passed through a 40-mesh sieve to obtain acrylic acid water-absorbing resin. The potassium persulfate solution was composed of potassium persulfate and deionized water according to the dosage ratio of 0.4 g:10 mL.

[0075] The woven fabric is a polypropylene woven fabric.

[0076] The geotextile is a non-woven geotextile. The fiber web of the non-woven geotextile is made of polyester, and the mass per unit area is 220 g / m 2 .

[0077] The preparation method of the above anti-seepage bentonite waterproof blanket includes the following steps:

[0078] Add the modified bentonite and acrylic acid superabsorbent resin into a stirring tank, stir and mix at 500 rpm for 30 min to obtain a composite superabsorbent material; evenly spread the composite superabsorbent material on the woven fabric, then lay the geotextile, and use the needling method to fix the composite superabsorbent material between the woven fabric and the geotextile, thus obtaining an anti-seepage bentonite waterproof blanket with a thickness of 3 mm and a mass per unit area of 4000 g / m 2 .

[0079] Comparative Example 3

[0080] An anti-seepage bentonite waterproof blanket, on the basis of Example 3, replace the modified bentonite in Example 3 with the product prepared in Comparative Example 1, and the remaining raw materials and preparation process are the same as those in Example 3.

[0081] Comparative Example 4

[0082] An anti-seepage bentonite waterproof blanket, on the basis of Example 3, replace the modified bentonite in Example 3 with the substance in Comparative Example 2, and the remaining raw materials, parameters and preparation process are the same as those in Example 3.

[0083] Comparative Example 5

[0084] An anti-seepage bentonite waterproof blanket, on the basis of Example 3, remove N-allyl-N'-(sodium sulfanilate) thiourea in the preparation process of the acrylic acid superabsorbent resin, and the remaining raw materials, parameters and preparation process are the same as those in Example 3.

[0085] Comparative Example 6

[0086] An anti-seepage bentonite waterproof blanket, on the basis of Example 3, remove the acrylic acid superabsorbent resin, and the remaining raw materials, parameters and preparation process are the same as those in Example 3.

[0087] Perform performance tests on the bentonite waterproof blankets obtained in Examples 3 - 5 and Comparative Examples 3 - 6. Specifically, refer to the method in the "Industry Standard for Sodium Bentonite Waterproof Blankets JG / T193 - 2006" to test the permeability coefficient. Then soak them in 10 wt% sodium chloride aqueous solution and 5 mg / L potassium dichromate aqueous solution for 30 d respectively, and detect the permeability coefficient again. After the soaking is completed, use an ultraviolet spectrophotometer to test the concentration of Cr(VI) in the remaining solution of the potassium dichromate aqueous solution, and calculate the removal rate of Cr(VI). The test results are shown in Table 2:

[0088] Table 2

[0089]

[0090] It can be seen from the data recorded in Table 2 that the permeability coefficient of the bentonite waterproof blankets prepared in Examples 3-5 is 2.6-3.4×10 -12 m / s. After being immersed in 10wt% sodium chloride aqueous solution for 30 days, the permeability coefficient is 2.7-3.5×10 -12 m / s. After being immersed in 5mg / L potassium dichromate aqueous solution for 30 days, the permeability coefficient is 2.9-3.9×10 -12 m / s, and the removal rate of Cr(VI) is above 99.6%. Compared with Comparative Examples 3-5, it not only has a smaller permeability coefficient, but also has better salt tolerance and Cr(VI) removal rate.

[0091] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0092] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An anti-seepage bentonite waterproof blanket, comprising a woven cloth and a geotextile, wherein a composite high water-absorbent material is arranged between the woven cloth and the geotextile, characterized in that: The composite super absorbent material comprises, by weight, 100 parts of modified bentonite and 2-8 parts of acrylic absorbent resin; Modified bentonite is made by the following steps: Add acrylamide to deionized water, stir and then add sodium bentonite, stir for 10-20 minutes, then ultrasonically treat for 30-60 minutes, add N,N'-methylenebisacrylamide, quaternary ammonium salt polyethyleneimine and potassium persulfate, react at 70-80°C for 2-2.5 hours, dry, and crush through a 40-mesh sieve to obtain modified bentonite; Acrylic water-absorbing resin is prepared by the following steps: Mix acrylic acid, sodium carboxymethyl cellulose and deionized water evenly, add N,N'-methylenebisacrylamide and N-allyl-N'-(sodium aminobenzenesulfonate) thiourea, add potassium persulfate solution dropwise at 60°C, react at 70°C for 2-3h after the addition is complete, dry at 80-100°C to constant weight, crush and pass through a 40-mesh sieve to obtain acrylic acid water-absorbing resin.

2. The anti-seepage bentonite waterproof blanket according to claim 1, characterized in that: The dosage ratio of deionized water, acrylamide, sodium bentonite, N,N'-methylenebisacrylamide, quaternary ammonium salt polyethyleneimine and potassium persulfate is 200-300 mL: 15.06-16.86 g: 45 g: 0.05 g: 4.5-5.0 g: 0.3-0.4 g.

3. The anti-seepage bentonite waterproof blanket according to claim 1, characterized in that: Quaternized polyethyleneimine is prepared by the following steps: The branched polyethyleneimine and anhydrous ethanol are mixed, allyl chloride is added, and the anhydrous ethanol is removed by rotary evaporation after reacting at 80°C for 24 hours, and the rotary evaporation product is dried; the mass ratio of the branched polyethyleneimine to the allyl chloride is 8:1.4-2.1, and the Mw of the branched polyethyleneimine is 800.

4. The anti-seepage bentonite waterproof blanket according to claim 1, characterized in that: The mass ratio of acrylic acid, sodium carboxymethyl cellulose, deionized water, N,N'-methylenebisacrylamide and N-allyl-N'-(sodium aminobenzenesulfonate) thiourea and potassium persulfate solution is 20g:2.6g:19-20mL:0.04g:2.5-4.5g:10mL, and the potassium persulfate solution is composed of potassium persulfate and deionized water in a dosage ratio of 0.4g:10mL.

5. The anti-seepage bentonite waterproof blanket according to claim 1, characterized in that: The woven fabric is polypropylene woven fabric or polyethylene woven fabric.

6. The anti-seepage bentonite waterproof blanket according to claim 1, characterized in that: Geotextile is a non-woven geotextile. The fiber mesh of non-woven geotextile is polyester or polypropylene fiber, and the unit area mass is 220g / m 2 .

7. A method for preparing an anti-seepage bentonite waterproof blanket according to any one of claims 1 to 6, characterized in that: The following steps are involved: Modified bentonite and acrylic absorbent resin are mixed to obtain a composite super absorbent material; the composite super absorbent material is evenly spread on a woven cloth, and then a geotextile is laid, and the composite super absorbent material is fixed between the woven cloth and the geotextile by a needle punching method to obtain an anti-seepage bentonite waterproof blanket.

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