Soil remediation modifying agent and soil remediation modifying method

Abstract

The invention relates to the technical field of soil remediation, in particular to a soil remediation modifying agent and a soil remediation modifying method. The soil remediation modifier is formed by crosslinking intercalation modified bentonite, vinyl grafted nano cellulose and N, N '-methylene bisacrylamide, and the intercalation modified bentonite is modified by adopting resveratrol betaine and dimethylallylamino ammonium chloride in a synergistic manner; the vinyl grafted nano cellulose is prepared through acylating chlorination-alkenylation reaction, and forms a chemical cross-linked network with the intercalated bentonite. Through the synergistic effect of multiple components, multifunctional integrated remediation of water retention, sand stabilization, heavy metal passivation and plant growth promotion is achieved, and the soil remediation agent has the advantages of being environmentally friendly, long-acting, stable, high in adaptability and the like and is suitable for desertification control and polluted soil ecological restoration.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and in particular to a soil remediation improver and a soil remediation improver method. Background Art

[0002] As the global soil degradation problem becomes increasingly serious, salinization and heavy metal pollution have become key factors restricting the sustainable development of agriculture. Traditional soil improvement technologies have bottlenecks such as single function, short duration of effectiveness, and poor environmental compatibility. In the field of saline-alkali land management, existing improvers mostly use gypsum, organic fertilizers and other materials. Although they can adjust the soil pH value in the short term, it is difficult to solve the problem of plant root hypoxia caused by rapid water evaporation and surface crusting; and conventional sand fixation agents (such as polyacrylamide) are easily degraded under high temperature and high salt conditions and lack ecological coordination. For heavy metal pollution, the current mainstream technologies include chemical stabilization (such as phosphate passivation) and microbial remediation, but the former is prone to phosphorus enrichment and secondary pollution, and the latter is difficult to apply on a large scale due to environmental adaptability limitations.

[0003] Patent document CN111040769B discloses a soil remediation agent and a soil remediation method. The soil remediation agent of the invention is low-cost, has good solidification and stabilization effects on heavy metals, and is suitable for large-scale application. The soil remediation method of the invention is simple to operate and has good remediation effects. Patent document CN115537206A discloses a saline-alkali soil remediation agent and a preparation method. The soil remediation agent is applied by spraying on the ground before land preparation, watering, or moderate to heavy rain. It can also be applied to the soil through drip irrigation, which can effectively improve soil salinization.

[0004] However, the above-mentioned improvers are too single and one-sided. Therefore, it is urgent to develop a new type of soil remediation improver to achieve the improvement and repair of land with both salinization and heavy metal pollution. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a soil remediation and improvement agent and a soil remediation and improvement method to achieve the improvement and remediation of land that is simultaneously salinized and contaminated by heavy metals.

[0006] Based on the above purpose, the present invention provides a soil remediation improver, which is obtained by cross-linking intercalated modified bentonite, vinyl grafted nanocellulose and N,N'-methylenebisacrylamide; the weight ratio of the intercalated modified bentonite, vinyl grafted nanocellulose and N,N'-methylenebisacrylamide is 0.5-1:0.3-0.5:3-5.

[0007] Preferably, the intercalation modified bentonite is obtained by intercalating resveratrol betaine and dimethylallylamino ammonium chloride into modified bentonite; the weight ratio of the resveratrol betaine, dimethylallylamino ammonium chloride and bentonite is 2-4:3-5:10-12.

[0008] The size of the bentonite is 0.5-1 mm.

[0009] Preferably, the resveratrol betaine is obtained by reacting the hydroxyl group of resveratrol with the acyl chloride group of betaine chlorochloride; the weight ratio of resveratrol to betaine chlorochloride is 2-3:3.5-5.

[0010] Preferably, the preparation method of the vinyl grafted nanocellulose is as follows:

[0011] (1) The nanocellulose is chlorinated with thionyl chloride to obtain chlorinated cellulose;

[0012] (2) The acyl chloride group of cellulose acylation reacts with the amino group of allylamine to obtain vinyl-grafted nanocellulose.

[0013] Preferably, the ratio of nanocellulose to thionyl chloride in step (1) is 10-12 g: 20-30 mL.

[0014] Preferably, in step (2), the ratio of cellulose acylate to allylamine is 8-10 g:15-20 mL.

[0015] Preferably, the size of the nanocellulose in step (1) is 50-200 nm.

[0016] Furthermore, the present invention also provides a soil improvement and remediation method, comprising the following steps: mixing a soil remediation agent with deionized water in a weight ratio of 1:50, and then adding 3-4 L / m 2 Spray it into the soil to be improved and maintain it for 10-30 days.

[0017] Beneficial effects of the present invention:

[0018] The soil improvement and repair agent of the present invention realizes the organic unity of multiple functions such as water conservation and sand fixation, heavy metal passivation, and plant growth promotion, and shows significant technical advantages in the field of salinization and heavy metal complex contaminated soil remediation.

[0019] This invention combines natural active ingredients with bentonite intercalation modification to create a composite interlayer structure with a rigid skeleton and flexible segments. The active ingredients provide dual sites for coordination and electrostatic adsorption of heavy metal ions, significantly improving their fixation efficiency. Furthermore, the synergistic effect of this structure with nanocellulose further enhances the formation of a three-dimensional network, resulting in the agent's long-lasting stability in sand fixation and water retention.

[0020] This invention addresses the agglomeration problem of bentonite and cellulose in traditional repair agents due to interfacial incompatibility by intercalating bentonite and olefinizing nanocellulose. The modified bentonite and nanocellulose form a homogeneous dispersion through chemical bonding and physical adsorption. This uniform dispersion not only enhances the mechanical strength of the repair agent but also creates a dynamic hydrogen bond network, significantly improving its water retention and wind erosion resistance.

[0021] The present invention uses naturally derived resveratrol and nanocellulose as core components, avoiding the potential toxicity of traditional chemical remediation agents to soil microorganisms and plants, and will not cause harmful effects on the natural growth of plants. The synergistic effect between the components reduces the bioavailability of heavy metals, while providing a suitable microenvironment for plant roots, thereby significantly improving the germination rate and growth vitality of plants. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0023] Example 1: A soil improvement and repair agent, the specific preparation steps are as follows:

[0024] (1) 2 g of resveratrol, 2.1 g of triethylamine, 20 mL of tetrahydrofuran, and 20 mL of N,N-dimethylformamide were mixed and stirred to obtain a mixed solution; 3.5 g of betaine chloride was then dispersed in 20 mL of tetrahydrofuran, and after uniform dispersion, the mixture was slowly added to the mixed solution and maintained at room temperature for 4 h. After the reaction was completed, resveratrol betaine was obtained by rotary evaporation;

[0025] (2) 10 g of bentonite was dispersed in 400 mL of deionized water and ultrasonically treated for 30 min. 50 mL of NaCl solution was then added and stirred at 60 °C for 12 h. The mixture was centrifuged and washed to obtain activated bentonite. 2 g of resveratrol betaine and 3 g of dimethylallylamino ammonium chloride were dissolved in deionized water, activated bentonite was added, and the mixture was stirred at 70 °C for 6 h under a nitrogen atmosphere. The resulting product was centrifuged and the precipitate was washed three times with ethanol / water (1:1). Finally, the mixture was freeze-dried in vacuum to obtain intercalated modified bentonite.

[0026] (3) Under nitrogen atmosphere, 10 g of nanocellulose was placed in a dry reactor, 100 mL of anhydrous N,N-dimethylformamide and 20 mL of thionyl chloride were added, mixed and stirred for 30 min, then heated to 40 °C for 12 h, the reaction solution was poured into ice ether for precipitation, filtered, washed with tetrahydrofuran, and vacuum dried at 40 °C for 6 h to obtain cellulose chloride;

[0027] (4) In a light-proof environment, 8 g of cellulose chloride was dispersed in 200 mL of anhydrous N,N-dimethylformamide, and then 15 mL of allylamine and 1 g of triethylamine were added dropwise to the reaction system. The reaction was allowed to proceed at room temperature for 40 h. The reaction solution was centrifuged, and the resulting precipitate was washed with tetrahydrofuran and methanol in sequence, and finally dried in vacuum at 35 °C for 24 h to obtain vinyl-grafted nanocellulose.

[0028] (5) 90 mL of deionized water, 0.5 g of intercalated modified bentonite, 3 g of N,N'-methylenebisacrylamide, 0.3 g of vinyl-grafted nanocellulose, and 0.5 g of ammonium persulfate were mixed and reacted at 70 °C for 4 h to obtain a soil remediation agent.

[0029] Example 2: A soil improvement and repair agent, the specific preparation steps are as follows:

[0030] (1) 2.5 g of resveratrol, 2.3 g of triethylamine, 23 mL of tetrahydrofuran, and 23 mL of N,N-dimethylformamide were mixed and stirred to obtain a mixed solution; 4 g of betaine chloride was then dispersed in 25 mL of tetrahydrofuran, and after uniform dispersion, the mixture was slowly added to the mixed solution and maintained at room temperature for 5 h. After the reaction was completed, resveratrol betaine was obtained by rotary evaporation;

[0031] (2) 11 g of bentonite was dispersed in 430 mL of deionized water and ultrasonically treated for 30 min. 50 mL of NaCl solution was then added and stirred at 60 °C for 12 h. The mixture was centrifuged and washed to obtain activated bentonite. 3 g of resveratrol betaine and 4 g of dimethylallylamino ammonium chloride were dissolved in deionized water, activated bentonite was added, and the mixture was stirred at 70 °C in a nitrogen atmosphere for 6 h. The obtained product was centrifuged and the precipitate was washed three times with ethanol / water (1:1). Finally, the mixture was freeze-dried in vacuum to obtain intercalated modified bentonite.

[0032] (3) Under nitrogen atmosphere, 11 g of nanocellulose was placed in a dry reactor, 110 mL of anhydrous N,N-dimethylformamide and 25 mL of thionyl chloride were added, mixed and stirred for 30 min, then heated to 43 °C for 12 h, the reaction solution was poured into ice ether for precipitation, filtered, washed with tetrahydrofuran, and vacuum dried at 40 °C for 6 h to obtain cellulose chloride;

[0033] (4) In a light-proof environment, 9 g of cellulose chloride was dispersed in 200 mL of anhydrous N,N-dimethylformamide, and then 18 mL of allylamine and 1.1 g of triethylamine were added dropwise to the reaction system. The reaction was allowed to react at room temperature for 45 h. The reaction solution was centrifuged, and the resulting precipitate was washed with tetrahydrofuran and methanol in sequence, and finally dried in vacuum at 35 °C for 24 h to obtain vinyl-grafted nanocellulose.

[0034] (5) 95 mL of deionized water, 0.8 g of intercalated modified bentonite, 4 g of N,N'-methylenebisacrylamide, 0.4 g of vinyl-grafted nanocellulose, and 1 g of ammonium persulfate were mixed and reacted at 70 °C for 4 h to obtain a soil remediation agent.

[0035] Example 3: A soil improvement and repair agent, the specific preparation steps are as follows:

[0036] (1) 3 g of resveratrol, 2.5 g of triethylamine, 25 mL of tetrahydrofuran, and 25 mL of N,N-dimethylformamide were mixed and stirred to obtain a mixed solution; 5 g of betaine chloride was then dispersed in 30 mL of tetrahydrofuran, and after uniform dispersion, the mixture was slowly added to the mixed solution and maintained at room temperature for 5 h. After the reaction was completed, resveratrol betaine was obtained by rotary evaporation;

[0037] (2) 12 g of bentonite was dispersed in 450 mL of deionized water, ultrasonically treated for 30 min, and then 50 mL of NaCl solution was added. The mixture was stirred at 60 °C for 12 h, centrifuged, and washed to obtain activated bentonite. 4 g of resveratrol betaine and 5 g of dimethylallylamino ammonium chloride were dissolved in deionized water, activated bentonite was added, and the mixture was stirred at 70 °C for 6 h under a nitrogen atmosphere. The resulting product was centrifuged, and the precipitate was washed three times with ethanol / water (1:1). Finally, the mixture was freeze-dried in vacuum to obtain intercalated modified bentonite.

[0038] (3) Under nitrogen atmosphere, 12 g of nanocellulose was placed in a dry reactor, 110 mL of anhydrous N,N-dimethylformamide and 30 mL of thionyl chloride were added, mixed and stirred for 30 min, then heated to 45 °C for 12 h, the reaction solution was poured into ice ether for precipitation, filtered, washed with tetrahydrofuran, and vacuum dried at 40 °C for 6 h to obtain cellulose chloride;

[0039] (4) In a light-proof environment, 10 g of cellulose chloride was dispersed in 200 mL of anhydrous N,N-dimethylformamide, and then 20 mL of allylamine and 1.2 g of triethylamine were added dropwise to the reaction system. The reaction was allowed to proceed at room temperature for 50 h. The reaction solution was centrifuged, and the resulting precipitate was washed with tetrahydrofuran and methanol in sequence, and finally dried in vacuum at 35 °C for 24 h to obtain vinyl-grafted nanocellulose.

[0040] (5) 100 mL of deionized water, 1 g of intercalated modified bentonite, 5 g of N,N'-methylenebisacrylamide, 0.5 g of vinyl-grafted nanocellulose, and 1.5 g of ammonium persulfate were mixed and reacted at 70 °C for 4 h to obtain a soil remediation agent.

[0041] Comparative Example 1: The difference from Example 2 is that resveratrol is replaced by phenol. The remaining steps are the same as Example 2. The specific preparation steps are as follows:

[0042] (1) 2.5 g of phenol, 2.3 g of triethylamine, 23 mL of tetrahydrofuran, and 23 mL of N,N-dimethylformamide were mixed and stirred to obtain a mixed solution; 4 g of chlorobetaine chloride was then dispersed in 25 mL of tetrahydrofuran, and after uniform dispersion, the mixture was slowly added to the mixed solution and maintained at room temperature for 5 h. After the reaction was completed, phenylbetaine was obtained by rotary evaporation;

[0043] (2) 11 g of bentonite was dispersed in 430 mL of deionized water and ultrasonically treated for 30 min. 50 mL of NaCl solution was then added and stirred at 60 °C for 12 h. The mixture was centrifuged and washed to obtain activated bentonite. 3 g of phenylbetaine and 4 g of dimethylallylaminoammonium chloride were dissolved in deionized water, activated bentonite was added, and the mixture was stirred at 70 °C for 6 h under a nitrogen atmosphere. The resulting product was centrifuged and the precipitate was washed three times with ethanol / water (1:1). Finally, the mixture was freeze-dried in vacuum to obtain intercalated modified bentonite.

[0044] (3) Under nitrogen atmosphere, 11 g of nanocellulose was placed in a dry reactor, 110 mL of anhydrous N,N-dimethylformamide and 25 mL of thionyl chloride were added, mixed and stirred for 30 min, then heated to 43 °C for 12 h, the reaction solution was poured into ice ether for precipitation, filtered, washed with tetrahydrofuran, and vacuum dried at 40 °C for 6 h to obtain cellulose chloride;

[0045] (4) In a light-proof environment, 9 g of cellulose chloride was dispersed in 200 mL of anhydrous N,N-dimethylformamide, and then 18 mL of allylamine and 1.1 g of triethylamine were added dropwise to the reaction system. The reaction was allowed to react at room temperature for 45 h. The reaction solution was centrifuged, and the resulting precipitate was washed with tetrahydrofuran and methanol in sequence, and finally dried in vacuum at 35 °C for 24 h to obtain vinyl-grafted nanocellulose.

[0046] (5) 95 mL of deionized water, 0.8 g of intercalated modified bentonite, 4 g of N,N'-methylenebisacrylamide, 0.4 g of vinyl-grafted nanocellulose, and 1 g of ammonium persulfate were mixed and reacted at 70 °C for 4 h to obtain a soil remediation agent.

[0047] Comparative Example 2: The difference from Example 2 is that resveratrol betaine is not added during intercalation. The remaining steps are the same as Example 2. The specific preparation steps are as follows:

[0048] (1) 11 g of bentonite was dispersed in 430 mL of deionized water and ultrasonically treated for 30 min. 50 mL of NaCl solution was then added and stirred at 60 °C for 12 h. The mixture was centrifuged and washed to obtain activated bentonite. 4 g of dimethylallylaminoammonium chloride was dissolved in deionized water and activated bentonite was added. The mixture was stirred at 70 °C in a nitrogen atmosphere for 6 h. The resulting product was centrifuged and the precipitate was washed three times with ethanol / water (1:1). Finally, the mixture was freeze-dried in vacuum to obtain intercalated modified bentonite.

[0049] (2) Under nitrogen atmosphere, 11 g of nanocellulose was placed in a dry reactor, 110 mL of anhydrous N,N-dimethylformamide and 25 mL of thionyl chloride were added, mixed and stirred for 30 min, then heated to 43 °C for 12 h, the reaction solution was poured into ice ether for precipitation, filtered, washed with tetrahydrofuran, and vacuum dried at 40 °C for 6 h to obtain cellulose chloride;

[0050] (3) In a light-proof environment, 9 g of cellulose chloride was dispersed in 200 mL of anhydrous N,N-dimethylformamide, and then 18 mL of allylamine and 1.1 g of triethylamine were added dropwise to the reaction system. The reaction was allowed to proceed at room temperature for 45 h. The reaction solution was centrifuged, and the resulting precipitate was washed with tetrahydrofuran and methanol in sequence, and finally dried in vacuum at 35 °C for 24 h to obtain vinyl-grafted nanocellulose.

[0051] (4) 95 mL of deionized water, 0.8 g of intercalated modified bentonite, 4 g of N,N'-methylenebisacrylamide, 0.4 g of vinyl-grafted nanocellulose, and 1 g of ammonium persulfate were mixed and reacted at 70 °C for 4 h to obtain a soil remediation agent.

[0052] Comparative Example 3: The difference from Example 2 is that the nanocellulose is not alkenylated and is directly mixed. The remaining steps are the same as Example 2. The specific preparation steps are as follows:

[0053] (1) 2.5 g of resveratrol, 2.3 g of triethylamine, 23 mL of tetrahydrofuran, and 23 mL of N,N-dimethylformamide were mixed and stirred to obtain a mixed solution; 4 g of betaine chloride was then dispersed in 25 mL of tetrahydrofuran, and after uniform dispersion, the mixture was slowly added to the mixed solution and maintained at room temperature for 5 h. After the reaction was completed, resveratrol betaine was obtained by rotary evaporation;

[0054] (2) 11 g of bentonite was dispersed in 430 mL of deionized water and ultrasonically treated for 30 min. 50 mL of NaCl solution was then added and stirred at 60 °C for 12 h. The mixture was centrifuged and washed to obtain activated bentonite. 3 g of resveratrol betaine and 4 g of dimethylallylamino ammonium chloride were dissolved in deionized water, activated bentonite was added, and the mixture was stirred at 70 °C in a nitrogen atmosphere for 6 h. The obtained product was centrifuged and the precipitate was washed three times with ethanol / water (1:1). Finally, the mixture was freeze-dried in vacuum to obtain intercalated modified bentonite.

[0055] (3) 95 mL of deionized water, 0.8 g of intercalated modified bentonite, 4 g of N,N'-methylenebisacrylamide, 0.4 g of nanocellulose, and 1 g of ammonium persulfate were mixed and reacted at 70 °C for 4 h to obtain a soil remediation agent.

[0056] Comparative Example 4: The difference from Example 2 is that bentonite is not intercalated and is directly added together with nanocellulose. The remaining steps are the same as Example 2. The specific preparation steps are as follows:

[0057] 95 mL of deionized water, 0.8 g of bentonite, 4 g of N,N'-methylenebisacrylamide, 0.4 g of ethyl nanocellulose and 1 g of ammonium persulfate were mixed and reacted at 70°C for 4 h to obtain a soil remediation agent.

[0058] Performance Testing

[0059] Water retention capacity: Mix sand and NaCl in a ratio of 100:3, take an appropriate amount of sand sample and place it in a culture dish, and then add 1L·m -2 The soil remediation and improvement dosage was sprayed on the surface of the sand sample. After the emulsion formed a crust on the surface of the sand sample, a certain amount of water was sprayed on the surface of the sand sample. The wet sand sample was placed in an oven at a constant temperature of 50°C. The sand sample was then weighed every 1 hour, and this was repeated 3 times. The water retention was determined based on the weight loss of the sand sample. The test results are shown in Table 1.

[0060] Sand fixation ability: The sand fixation ability is evaluated by measuring the wind erosion modulus. The sand sample is dried for 24 hours at a temperature of 50°C and a humidity of 30%. The soil remediation agent solution is sprayed on the surface of the sand cone model at a spraying volume of 1 L·m -2 , wind erosion resistance test was carried out, and the test results are shown in Table 1;

[0061] Potted plant experiment: 1 kg of Inner Mongolia sandy soil sample mixed with 3 wt.% NaCl was placed in a flower pot (13 cm height, 12 cm surface diameter). A soil remediation agent was added and mixed thoroughly. Then, the potted plant experiment was carried out at room temperature of 20°C. A certain amount of water was added to the soil daily. 15 alfalfa seeds were sown in each flower pot. The germination rate was recorded 15 days after sowing. Each group was repeated three times. The test results are shown in Table 1.

[0062] Heavy metal content: 8 kg of soil was taken and divided into 8 parts. Seven of the parts were treated with soil remediation agents obtained from the implementation forest and the control group respectively. The remaining group was the control group. The TCLP toxicity leaching method was used to determine the heavy metal content in the soil. The Cd 2+ The content is 7.6 mg / kg, and the test results are shown in Table 1.

[0063] Table 1 Performance test results

[0064]

[0065]

[0066] Data analysis: From the test data of Examples 1-3 in Table 1, it can be seen that the soil improvement and repair agent prepared by the present invention exhibits significant comprehensive performance advantages in practical applications. The 12h water retention rate is not less than 65.9%, indicating that the formula can effectively reduce water loss and significantly improve the water retention of saline-alkali sandy soil; in the wind erosion resistance test, the wind erosion modulus of the embodiment can reach a minimum of (0.15g / (m 2 ·min), showing excellent wind resistance and sand fixation capabilities; it also has excellent heavy metal adsorption performance. Moreover, the alfalfa germination rate in the potted experiment was as high as 88.2%, which shows that the formula will not have a negative impact on plant growth. The present invention achieves the synergistic improvement of multiple functions such as water retention, sand fixation, growth promotion and heavy metal remediation, providing an efficient solution for the treatment of salinization and heavy metal composite contaminated soil.

[0067] From the comparison of the test data of Example 2 and Comparative Examples 1 and 2 in Table 1, it can be seen that the use of resveratrol betaine instead of phenol as a modified component can systematically improve the comprehensive performance of the soil remediation modifier. On the one hand, the large steric hindrance effect of the rigid aromatic ring structure of resveratrol helps to maintain the stability of the interlayer channel. On the other hand, its own double bonds can cross-link with the vinyl-grafted nanocellulose to form a network, which may be the structural basis for improving the water retention and sand fixation effects of the modifier. At the same time, it may form a weak π-π interaction with the nanocellulose, so that the nanocellulose can produce a certain cross-linking during subsequent polymerization; in terms of heavy metal passivation, the phenolic hydroxyl group and the betaine group of the resveratrol derivative can interact with Cd through the dual effects of coordination and electrostatics. 2+The formation of a stable complex, and its large molecular size advantage over phenol makes this action more spatially selective, thus enhancing its adsorption and complexation ability for heavy metal ions. Regarding plant growth promotion, resveratrol betaine has a more moderate biological activity than traditional phenolic compounds, which may reduce the inhibition of microorganisms and prevent it from significantly affecting the natural growth of plants. This multifunctional synergistic enhancement effect indicates that the introduction of resveratrol betaine optimizes the overall performance of the soil remediation agent.

[0068] From the comparison of the test data of Example 2 and Comparative Example 3 in Table 1, it can be seen that the olefinic modification treatment of nanocellulose plays a key role in improving the comprehensive performance of the soil remediation improver. On the one hand, vinyl grafted nanocellulose can intercalate modified bentonite to form a stable three-dimensional interpenetrating network structure, and the introduction of high-density chemical cross-linking points enhances the bonding strength between sand particles; at the same time, the active groups on the surface of nanocellulose and the interlayer domains of bentonite synergistically provide more binding sites, enhancing the adsorption of heavy metal ions; on the other hand, vinyl grafted nanocellulose and intercalated modified bentonite have a certain synergistic effect, and the linear molecular chains of vinyl nanocellulose form "molecular bridges" between the bentonite layers, which not only enhances the mechanical strength of the three-dimensional network structure, but also optimizes the pore distribution. At the same time, the hydrophilic groups of nanocellulose form a hydrogen bond network with the interlayer water of bentonite, constructing a multi-level water storage structure; and for heavy metal passivation, the active groups on the surface of nanocellulose form multiple coordination sites with the resveratrol betaine between the bentonite layers, which significantly improves the Cd 2 + fixation efficiency. This structural synergy achieved through molecular design enables the modifier to achieve significantly improved functional durability and environmental adaptability while maintaining environmental friendliness.

[0069] From the comparison of the performance test data of Example 2 and Comparative Example 4, it can be seen that the composite process of using resveratrol betaine intercalation to modify bentonite and combining it with olefinated nanocellulose makes the soil remediation improver show significant advantages in water retention, sand fixation, plant growth promotion and heavy metal passivation. The improved dispersibility of the intercalated bentonite avoids the interface defects caused by particle agglomeration, and also avoids the aggravation of the agglomeration phenomenon caused by weak π-π interaction between bentonite and nanocellulose. Comparative Example 4 omits the intercalation modification step, resulting in deterioration of the interfacial compatibility between bentonite and nanocellulose, forming a heterogeneous structure, thereby showing a systematic decline in various performance indicators.

[0070] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A soil remediation improver, characterized in that: It is obtained by cross-linking intercalation modified bentonite, vinyl grafted nanocellulose and N,N'-methylenebisacrylamide; the weight ratio of intercalation modified bentonite, vinyl grafted nanocellulose and N,N'-methylenebisacrylamide is 0.5-1:0.3-0.5:3-5; The intercalation modified bentonite is obtained by intercalating resveratrol betaine and dimethylallylamino ammonium chloride into modified bentonite; the weight ratio of the resveratrol betaine, dimethylallylamino ammonium chloride and bentonite is 2-4:3-5:10-12; The resveratrol betaine is obtained by reacting the hydroxyl group of resveratrol with the acyl chloride group of betaine chloride.

2. The soil remediation and improvement agent according to claim 1, characterized in that The weight ratio of the resveratrol to betaine chlorochloride is 2-3:3.5-5.

3. The soil remediation and improvement agent according to claim 1, characterized in that The size of the bentonite is 0.5-1 mm.

4. The soil remediation and improvement agent according to claim 1, characterized in that The vinyl grafted nanocellulose is obtained by reacting cellulose acylate and allylamine.

5. The soil remediation and improvement agent according to claim 4, characterized in that The usage ratio of the cellulose acylate chloride and allylamine is 8-10 g:15-20 mL.

6. The soil remediation and improvement agent according to claim 4, characterized in that The cellulose chloride is obtained by chlorinating nanocellulose with thionyl chloride, wherein the usage ratio of the nanocellulose and thionyl chloride is 10-12 g:20-30 mL.

7. A soil improvement and remediation method, characterized in that: The following steps are included: mixing the soil remediation agent with deionized water at a weight ratio of 1:50, and then adding 3-4 L / m 2 Spray it into the soil to be improved and maintain it for 10-30 days.

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