Supramolecular hydrogel as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of environmental restoration, and particularly relates to supramolecular hydrogel as well as a preparation method and application thereof. The supramolecular hydrogel adhesive tape provided by the invention is provided with charges and cavities, can include plant hormone salicylic acid, and is cooperated with phytoremediation to remove heavy metals in soil, and the supramolecular hydrogel adhesive tape is high in environmental remediation efficiency and short in remediation period. The supramolecular hydrogel provided by the invention is a load type supramolecular hydrogel composed of amino clay and carboxymethyl beta-cyclodextrin. A cavity of the carboxymethyl beta-cyclodextrin can effectively contain the plant hormone salicylic acid, the carboxymethyl beta-cyclodextrin and the plant hormone salicylic acid are well compatible, and then the binary supramolecular hydrogel is obtained through electro-static interaction between the amino clay and the carboxymethyl beta-cyclodextrin. The supramolecular hydrogel provided by the invention has the superiority of controllably releasing plant hormones based on two orthogonal non-covalent interactions, and can become an efficient platform for sustainable environmental remediation by cooperating with phytoremediation.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental restoration, and in particular relates to a supramolecular hydrogel and a preparation method and application thereof. Background Art

[0002] With human activities and industrial development, soil pollution, such as heavy metal pollution and organic matter pollution, has become increasingly serious. Research has begun to explore how to effectively remediate polluted soils. Compared to other remediation methods, phytoremediation, as a bioremediation method, offers advantages such as environmental friendliness, sustainability, low cost, long-lasting effects, and ease of implementation.

[0003] However, the efficiency of phytoremediation is low, the restoration cycle is long, and it cannot repair the soil environment in a timely manner. Summary of the Invention

[0004] The purpose of the present invention is to provide a supramolecular hydrogel and a preparation method and application thereof. The supramolecular hydrogel provided by the present invention cooperates with plant repair, has high repair efficiency and short repair cycle.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a supramolecular hydrogel. The building blocks of the supramolecular hydrogel include carboxymethyl beta-cyclodextrin and amino clay that interacts with the carboxymethyl beta-cyclodextrin through electrostatic force.

[0007] Preferably, the mass ratio of the carboxymethyl β-cyclodextrin to amino clay is 30-40:19-32.

[0008] Preferably, the building blocks of the supramolecular hydrogel further include plant hormones; the plant hormones are included in the cavity of the carboxymethyl β-cyclodextrin.

[0009] Preferably, the mass ratio of the carboxymethyl β-cyclodextrin to the plant hormone is 1139:14-138.

[0010] The present invention also provides a method for preparing the supramolecular hydrogel described in the above scheme, comprising the following steps:

[0011] mixing carboxymethyl-β-cyclodextrin and the first water to obtain a stock solution;

[0012] The stock solution, amino clay and second water are mixed and coagulated to obtain the supramolecular hydrogel.

[0013] Preferably, the molar volume ratio of the carboxymethyl-β-cyclodextrin to the first water is 10 mmol: (9-12) mL; the mass volume ratio of the amino clay to the stock solution is (0.3-0.4) g: (0.15-0.25) mL; the volume ratio of the stock solution to the second water is 0.15-0.25:1; and the molar concentration of the stock solution is 0.8-1.1 mol / L.

[0014] Preferably, after the coagulation, the product is allowed to stand and then freeze-dried; the freeze-drying includes a pre-cooling stage and a drying stage in sequence; the temperature of the pre-cooling stage is not higher than -40°C, and the insulation pre-cooling time is 1 to 1.5 hours; the temperature of the drying stage is -70 to -50°C, and the insulation drying time is 48 to 72 hours.

[0015] Preferably, the building blocks of the supramolecular hydrogel further include plant hormones, and the method for preparing the supramolecular hydrogel comprises the following steps: mixing carboxymethyl-β-cyclodextrin, plant hormones, and a first water to obtain a stock solution; and mixing the stock solution, amino clay, and a second water to form a coagulation to obtain the supramolecular hydrogel.

[0016] Preferably, the molar ratio of the carboxymethyl-β-cyclodextrin to the plant hormone is 10:1-10.

[0017] The present invention also provides the use of the supramolecular hydrogel described in the above scheme or the supramolecular hydrogel obtained by the preparation method described in the above scheme in removing heavy metals in soil.

[0018] The present invention provides a supramolecular hydrogel. The supramolecular hydrogel provided by the present invention has an electric charge and a cavity, and can encapsulate plant hormones, thereby cooperating with plant remediation to achieve the removal of heavy metals in the soil. The environmental remediation efficiency is high, the remediation cycle is short, and the soil heavy metal ion removal rate is above 40% in 40 days. The supramolecular hydrogel provided by the present invention is a loaded supramolecular hydrogel composed of amino clay and carboxymethyl β-cyclodextrin. After encapsulating plant hormones, it becomes a binary supramolecular hydrogel. There is an electrostatic interaction between amino clay (AC) and carboxymethyl β-cyclodextrin (CM-β-CD). The cavity of carboxymethyl β-cyclodextrin can effectively encapsulate plant hormones (SA). The two are well compatible. The structure is represented as follows The supramolecular hydrogel provided by the present invention is based on two orthogonal non-covalent interactions - electrostatic interaction and host-guest interaction (carboxymethyl β-cyclodextrin as the host and plant hormones as the guest), and has the advantage of controlled release of plant hormones, which may make it an efficient platform for sustainable soil environmental remediation.

[0019] The present invention also provides a method for preparing the supramolecular hydrogel described in the above scheme. The preparation method provided by the present invention has simple steps, convenient operation, high feasibility, and is suitable for industrial production.

[0020] The present invention also provides the use of the supramolecular hydrogel described in the above scheme, or the supramolecular hydrogel obtained by the preparation method described in the above scheme, for removing heavy metals from soil. The supramolecular hydrogel provided by the present invention is charged and has a cavity structure. Combined with phytoremediation, it synergistically removes heavy metals from soil, achieving high environmental remediation efficiency and strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 is a synthetic route of amino clay in the present invention;

[0023] Figure 2 Schematic diagram of the synthesis of supramolecular hydrogel in the present invention;

[0024] Figure 3 is a scanning electron micrograph of the amino clay and supramolecular hydrogel of Example 1 of the present invention; wherein a is b is amino clay;

[0025] Figure 4 The XRD spectra of the amino clay and supramolecular hydrogel of Example 1 of the present invention are shown in FIG. 1 , wherein a represents amino clay and b represents supramolecular hydrogel.

[0026] Figure 5 FT-IR spectra of the amino clay and supramolecular hydrogel of Example 1 of the present invention;

[0027] Figure 6 This is a gelation diagram of the supramolecular hydrogel of Example 1 of the present invention;

[0028] Figure 7 This is a scanning diagram of the rheological properties and strain amplitude test of the supramolecular hydrogel of Example 1 of the present invention; wherein a is the rheological properties and b is the strain amplitude;

[0029] Figure 8 The carboxymethyl β-cyclodextrin-plant hormone inclusion compound of Example 1 of the present invention Bond strength spectrum; where a is the absorbance at different wavelengths, and b is the relationship between CMCD concentration (carboxymethyl β-cyclodextrin concentration) and △Abs (change in absorbance);

[0030] Figure 9 Schematic diagram of the structure of carboxymethyl β-cyclodextrin. DETAILED DESCRIPTION

[0031] The present invention provides a supramolecular hydrogel. The building blocks of the supramolecular hydrogel include carboxymethyl beta-cyclodextrin and amino clay that interacts with the carboxymethyl beta-cyclodextrin through electrostatic force.

[0032] The building blocks of the supramolecular hydrogel provided by the present invention include carboxymethyl β-cyclodextrin; the structure of the carboxymethyl β-cyclodextrin is as follows: Figure 9 shown.

[0033] The building blocks of the supramolecular hydrogel provided by the present invention include amino clay that interacts with the carboxymethyl beta-cyclodextrin through electrostatic force.

[0034] In the present invention, the mass ratio of the carboxymethyl β-cyclodextrin to amino clay is preferably 30-40:19-32, specifically 30:19, 30:25, 30:32, 40:19, 40:25 or 40:32.

[0035] The building blocks of the supramolecular hydrogel provided by the present invention preferably also include plant hormones encapsulated in the cavity of the carboxymethyl β-cyclodextrin; the plant hormones preferably include one or more of salicylic acid, indoleacetic acid, ethylene, strigolactone, jasmonic acid and cytokinin; the structure of salicylic acid is shown in Formula B.

[0036]

[0037] In the present invention, the mass ratio of the carboxymethyl β-cyclodextrin to the plant hormone is preferably 1139:14 to 139, specifically 1139:14, 1139:83, 1139:97, 1139:111, 1139:125 or 1139:139.

[0038] The present invention also provides a method for preparing the supramolecular hydrogel described in the above scheme, comprising the following steps:

[0039] mixing carboxymethyl-β-cyclodextrin and the first water to obtain a stock solution;

[0040] The stock solution, amino clay and second water are mixed and coagulated to obtain the supramolecular hydrogel.

[0041] In the present invention, carboxymethyl-β-cyclodextrin is mixed with first water to obtain a stock solution. In the present invention, the first water is preferably deionized water.

[0042] In the present invention, the molar volume ratio of the carboxymethyl-β-cyclodextrin to the first water is preferably 10 mmol:(9-12) mL, specifically 10 mmol:9 mL, 10 mmol:10 mL, 10 mmol:11 mL or 10 mmol:12 mL.

[0043] After obtaining the stock solution, the present invention mixes the stock solution, amino clay and a second water (referred to as the first mixing) to form a coagulation to obtain the supramolecular hydrogel. In the present invention, the preparation method of the amino clay (AC) is preferably based on Chinese patent CN112011098A.

[0044] In the present invention, the second water is preferably deionized water.

[0045] In the present invention, the first mixing is preferably: stirring and mixing amino clay and water (referred to as stirring A) until the solution is clear to obtain an amino clay aqueous solution, and further stirring and mixing the stock solution and the amino clay aqueous solution (referred to as stirring B).

[0046] In the present invention, the mass volume ratio of the amino clay to the stock solution is preferably (0.3-0.4) g:(0.15-0.25) mL, specifically 0.3 g:0.15 mL, 0.35 g:0.15 mL, 0.4 g:0.15 mL, 0.3 g:0.2 mL, 0.35 g:0.2 mL, 0.4 g:0.2 mL, 0.3 g:0.25 mL, 0.35 g:0.25 mL or 0.4 g:0.25 mL.

[0047] In the present invention, the volume ratio of the reserve solution to the second water is preferably 0.15 to 0.25:1, specifically 0.15:1, 0.17:1, 0.19:1, 0.21:1, 0.23:1 or 0.25:1.

[0048] In the present invention, the molar concentration of the stock solution is preferably 0.8 to 1.1 mol / L, specifically 0.8 mol / L, 0.9 mol / L, 1 mol / L or 1.1 mol / L.

[0049] In the present invention, the rotation speed of the stirring A is preferably 480-960 rpm, specifically 480 rpm, 600 rpm, 720 rpm, 840 rpm or 960 rpm, and the stirring time is preferably 20-40 min, specifically 25 min, 30 min or 35 min.

[0050] In the present invention, the rotation speed of the stirring B is preferably 480-960 rpm, specifically 480 rpm, 600 rpm, 720 rpm, 840 rpm or 960 rpm, and the stirring time is preferably 10-15 min, specifically 11 min or 12 min.

[0051] In the present invention, the coagulation temperature is preferably 15-40°C, specifically 20°C or 25°C.

[0052] In the present invention, the coagulation preferably further comprises allowing the obtained product to stand and then freeze-drying.

[0053] In the present invention, the standing time is preferably 4 to 32 hours, specifically 12 hours or 24 hours.

[0054] In the present invention, the freeze-drying preferably includes a pre-cooling stage and a drying stage in sequence; the temperature in the pre-cooling stage is preferably not higher than -40°C, specifically -40°C, -45°C, -50°C, -55°C or -60°C, and the insulation pre-cooling time is preferably 1 to 1.5 hours, specifically 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours or 1.5 hours.

[0055] In the present invention, the temperature in the drying stage is preferably -70 to -50°C, specifically -70°C, -65°C, -60°C, -55°C or -50°C; the heat preservation and drying time is preferably 48 to 72h, specifically 48h, 54h, 60h, 66h or 72h; the freeze-drying equipment is preferably a freeze dryer.

[0056] In the present invention, the building blocks of the supramolecular hydrogel further include plant hormones, and the method for preparing the supramolecular hydrogel comprises the following steps: mixing carboxymethyl-β-cyclodextrin, plant hormones, and a first water (denoted as a second mixture) to obtain a stock solution; and mixing the stock solution, amino clay, and the second water to form a coagulation to obtain the supramolecular hydrogel.

[0057] In the present invention, the molar ratio of the carboxymethyl-β-cyclodextrin to the plant hormone is preferably 10:1 to 10, specifically 10:1, 10:2, 10:3, 10:4, 10:5, 10:6, 10:7, 10:8, 10:9 or 10:10.

[0058] In the present invention, the second mixing is preferably performed by stirring mixing and ultrasonic mixing in sequence; the stirring mixing speed is preferably 900-1300 rpm, specifically 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm or 1300 rpm, and the mixing time is preferably 1-2 h, specifically 1.5 h; the ultrasonic mixing time is preferably 0.5-1.5 h, specifically 1 h.

[0059] In the preparation method provided by the present invention, carboxymethyl-β-cyclodextrin is a macrocyclic host obtained by replacing the hydroxyl groups on β-cyclodextrin with carboxymethyl groups. An inclusion complex of carboxymethyl cyclodextrin and plant hormones is obtained through host-guest interaction. Subsequently, the negatively charged inclusion complex and positively charged amino clay are constructed through electrostatic interaction to obtain a supramolecular hydrogel containing plant hormones.

[0060] The present invention also provides the use of the supramolecular hydrogel described in the above scheme or the supramolecular hydrogel obtained by the preparation method described in the above scheme in removing heavy metals in soil.

[0061] In the present invention, the heavy metals in the soil heavy metals preferably include one or more of lead, copper and cadmium.

[0062] In the present invention, the application of the supramolecular hydrogel in removing heavy metals in soil preferably includes the following steps: adding the supramolecular hydrogel to the soil (denoted as the third mixture), and then transplanting plants into the soil for cultivation to form a repair system with the plants; the supramolecular hydrogel is the supramolecular hydrogel described in the above scheme or the supramolecular hydrogel obtained by the preparation method described in the above scheme.

[0063] In the present invention, the method preferably further comprises adding a nutrient solution to the soil before transplanting the plants; the nutrient solution is preferably Hoagland nutrient solution or a prepared Hoagland nutrient solution.

[0064] In the present invention, the nutrient components of the Hoagland nutrient solution are preferably: 607 mg / L potassium sulfate, 115 mg / L ammonium dihydrogen phosphate, 493 mg / L magnesium sulfate, 20 mg / L sodium ferric EDTA, 2.86 mg / L ferrous sulfate, 4.5 mg / L borax, 2.13 mg / L manganese sulfate, 0.05 mg / L copper sulfate, 0.22 mg / L zinc sulfate and 0.02 mg / L ammonium sulfate.

[0065] In the present invention, the preparation method of the Hoagland nutrient solution is preferably: mixing the Hoagland nutrient solution, calcium salt and water (referred to as the fourth mixing); the calcium salt is preferably calcium nitrate tetrahydrate; and the water is preferably distilled water.

[0066] In the present invention, the mass ratio of the Hoagland nutrient solution to the calcium salt is preferably 1260:945; the mass ratio of Hoagland to water in the Hoagland nutrient solution is preferably 1.26:1000-4000, specifically 1.26:1000, 1.26:2000, 1.26:3000 or 1.26:4000.

[0067] In the present invention, the fourth mixing is preferably heating mixing; the temperature of the heating mixing is preferably based on the dissolution of the Hoagland nutrient solution and calcium salt into water.

[0068] In the present invention, the concentration of heavy metals in the soil is preferably not higher than 10 mg / (kg dry soil), specifically 10 mg / (kg dry soil), 8 mg / (kg dry soil), 6 mg / (kg dry soil), 4 mg / (kg dry soil), 2 mg / (kg dry soil) or 1 mg / (kg dry soil).

[0069] In the present invention, the mass ratio of the supramolecular hydrogel to the soil to be repaired can be 2770-7354:8×10 6 , specifically 2770:8×10 6 、3000:8×10 6 、3500:8×10 6 、4000:8×10 6 、4500:8×10 6 、5000:8×10 6 、5500:8×10 6 、6000:8×10 6 、6500:8×10 6 、7000:8×10 6 or 7354:8×10 6 The present invention ensures that the sustained-release amount of plant hormones matches the plant's demand for plant hormones by adding the above amount of supramolecular hydrogel and coordinating the plant transplantation density.

[0070] In the present invention, the plant transplantation is preferably performed by transplanting the plant into soil so that the supramolecular hydrogel is dispersed in the plant rhizosphere. This ensures that the supramolecular hydrogel accumulates near the plant rhizosphere, thereby enhancing the effective growth-promoting effect of the supramolecular hydrogel on the plant through the sustained release of plant hormones.

[0071] In the present invention, the density of the plant transplantation can be 45 to 55 plants / m 2 , specifically 50 plants / m 2 .

[0072] In the present invention, after the plant is transplanted, the soil is preferably replenished with water every day; the mass ratio of water used for replenishment to supramolecular hydrogel can be 50-150:0.2770-0.7354, specifically 75:0.3, 75:0.4, 75:0.5, 75:0.6, 75:0.7, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.7354, 125:0.3, 125:0.4, 125:0.5, 125:0.6 or 125:0.7. The present invention is beneficial to restore and maintain the structure of the supramolecular hydrogel by replenishing water, which is beneficial to its function.

[0073] In the present invention, the plant is preferably one or more of a hyperaccumulator and a landscape plant; the hyperaccumulator is preferably one or both of amaranth and nightshade; the landscape plant preferably includes one or more of lotus, reed, reed, water lily and calamus.

[0074] In the present invention, the culture time is preferably more than 40 days.

[0075] In order to further illustrate the present invention, the scheme of the present invention is described in detail below with reference to the accompanying drawings and embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0076] Example 1

[0077] The supramolecular hydrogel prepared in this example has carboxymethyl cyclodextrin as the host and salicylic acid as the guest.

[0078] The method for preparing the supramolecular hydrogel in this embodiment comprises the following steps:

[0079] (1) Preparation of amino clay, the synthesis route is as follows Figure 1 (Refer to Chinese Patent CN112011098A): Weigh 10.08 g of magnesium chloride hexahydrate and 3-aminopropyltriethoxysilane, dissolve in 240 mL of anhydrous ethanol, slowly stir for 24 hours, centrifuge at 4000 rpm for 8 minutes, collect the white precipitate, wash three times with ethanol, dry in a vacuum at 40°C for 48 hours, and grind to obtain amino clay as a light yellow powder.

[0080] (2) Prepare the carboxymethyl β-cyclodextrin-salicylic acid inclusion complex stock solution. The synthesis diagram is as follows: Figure 2 : Add carboxymethyl-β-cyclodextrin and salicylic acid into deionized water, stir and dissolve, and ultrasonicate for 1 hour to fully dissolve them. The ratio of added carboxymethyl-β-cyclodextrin, salicylic acid and deionized water is 10mmol:10mmol:9mL to obtain a carboxymethyl-β-cyclodextrin-salicylic acid inclusion complex stock solution with a concentration of 1.1mol / L.

[0081] (3) 0.4 g of the amino clay prepared in step (1) was added to deionized water and stirred at 900 r / min for 20 min until the solution became clear. The carboxymethyl β-cyclodextrin-salicylic acid inclusion compound stock solution prepared in step (2) was added to the above solution and stirred for 15 min. The ratio of the amino clay, carboxymethyl β-cyclodextrin-salicylic acid inclusion compound stock solution to deionized water was 0.4 g:0.15 mL:1 mL. The solution was allowed to stand for 12 h and freeze-dried at -60°C for 72 h to obtain a powdered supramolecular hydrogel.

[0082] The performance of supramolecular hydrogel was tested by rheometer and scanning electron microscope, the structure of supramolecular hydrogel was observed by infrared spectroscopy and XRD, and the inclusion bonding constant of carboxymethyl β-cyclodextrin-salicylic acid inclusion complex was determined by ultraviolet absorption. Figures 3 to 8 shown.

[0083] Figure 3 The scanning electron micrographs of amino clay and supramolecular hydrogel of this embodiment are shown in FIG. Figure 3 It can be seen that the lamellar structure of amino clay is preserved in the gel, eventually forming a porous lamellar structure.

[0084] Figure 4 is the XRD spectrum of the amino clay and supramolecular hydrogel of this embodiment, Figure 5 The FT-IR spectra of amino clay and supramolecular hydrogel in this embodiment are as follows. Figures 4-5 It can be seen that the structure of amino clay has not changed substantially during the gel formation process.

[0085] Figure 6 The gelation diagram of the supramolecular hydrogel of this embodiment is shown in FIG. Figure 6 It can be seen that this embodiment forms an inverted and non-flowing stable supramolecular hydrogel.

[0086] Figure 7 The rheological properties and strain amplitude test scan of the supramolecular hydrogel of this embodiment are shown in FIG. Figure 7 It can be seen that the material prepared in this example does have the viscoelasticity of gel.

[0087] Figure 8 The bonding strength spectrum of the carboxymethyl β-cyclodextrin-salicylic acid inclusion complex of this embodiment is shown in FIG. Figure 8 It can be seen that the inclusion bonding constant of salicylic acid and carboxymethyl cyclodextrin is 8.2×10 2 M –1 .

[0088] Example 2

[0089] The preparation method of this embodiment is the same as that of Example 1, except that the molar ratio of carboxymethyl-β-cyclodextrin to salicylic acid is 10:1.

[0090] Example 3

[0091] The preparation method of this embodiment is the same as that of Example 1, except that the molar ratio of carboxymethyl-β-cyclodextrin to salicylic acid is 10:5.

[0092] Example 4

[0093] The preparation method of this embodiment is the same as that of Example 1, except that the molar volume ratio of carboxymethyl-β-cyclodextrin to the first water is 10 mmol:12 mL.

[0094] Example 5

[0095] The preparation method of this example is the same as that of Example 1, except that the mass volume ratio of amino clay to carboxymethyl β-cyclodextrin-salicylic acid inclusion compound stock solution is 0.3 g:0.25 mL.

[0096] Example 6

[0097] The method for preparing the supramolecular hydrogel in this embodiment comprises the following steps:

[0098] (1) Preparation of amino clay (refer to Chinese patent CN112011098A): Magnesium chloride hexahydrate and 10.08 g of 3-aminopropyltriethoxysilane were weighed and dissolved in 240 mL of anhydrous ethanol. The mixture was slowly stirred for 24 h, and the white precipitate was collected by centrifugation at 4000 rpm for 8 min. The precipitate was washed three times with ethanol, dried under vacuum at 40°C for 48 h, and ground to obtain amino clay as a light yellow powder.

[0099] (2) Preparation of stock solution: Carboxymethyl-β-cyclodextrin was added to deionized water and stirred to dissolve, and ultrasonicated for 1 h to fully dissolve it. The ratio of carboxymethyl-β-cyclodextrin to deionized water was 10 mmol:9 mL to obtain a stock solution with a concentration of 1.1 mol / L.

[0100] (3) 0.4 g of the amino clay prepared in step (1) was added to deionized water and stirred at 900 r / min for 20 min until the solution became clear. The stock solution prepared in step (2) was added to the above solution and stirred for 15 min. The ratio of amino clay, stock solution, and deionized water was 0.4 g:0.15 mL:1 mL. The solution was allowed to stand for 12 h and freeze-dried at -60°C for 72 h to obtain a powdered supramolecular hydrogel.

[0101] Example 7

[0102] The preparation method of this embodiment is the same as that of Example 6, except that the molar volume ratio of carboxymethyl-β-cyclodextrin to the first water is 10 mmol:12 mL.

[0103] Example 8

[0104] The preparation method of this example is the same as that of Example 6, except that the mass volume ratio of amino clay to carboxymethyl β-cyclodextrin-salicylic acid inclusion compound stock solution is 0.3 g:0.25 mL.

[0105] The test results of Examples 2 to 5 are similar to those of Example 1.

[0106] Test Example 1

[0107] This test example uses the supramolecular hydrogel prepared in Example 1 to remove cadmium from soil. The specific steps are as follows:

[0108] (1) Uncontaminated soil was placed in a polyethylene flowerpot. 10.16 mg of CdCl2 was weighed and dissolved in 200 mL of deionized water. The solution was added to 0.8 kg of uncontaminated soil to make the Cd concentration in the soil 8.38 ± 0.14 mg / kg dry soil. 0.7354 g of supramolecular hydrogel was added to the soil and mixed evenly.

[0109] (2) Select Solanum nigrum seedlings of uniform size and transplant them into polyethylene pots, with one Solanum nigrum seedling transplanted into each pot. After the plants have grown for 40 days, the cadmium concentration of the soil before and after remediation is measured according to the national standard GB / T17141-1997, and the cadmium removal rate is calculated. The results are shown in Table 1.

[0110] Table 1 Cd removal of test example 1

[0111]

[0112] According to Table 1, it can be seen that the supramolecular hydrogel combined with Solanum nigrum effectively removed cadmium from the soil, with a removal rate of 58.4%, which is a high cadmium removal rate.

[0113] Test Example 2

[0114] The method of this test example is the same as that of Test Example 1, except that the plant used is Amaranthus oleraceus. The results are shown in Table 2.

[0115] Table 2 Cd removal of test example 2

[0116]

[0117] According to Table 2, it can be seen that the supramolecular hydrogel combined with grain amaranth effectively removed cadmium from the soil, with a removal rate of 41.5%, which is a high cadmium removal rate.

[0118] Test Example 3

[0119] The supramolecular hydrogel prepared in Example 1 was used to remove heavy metals from soil. The specific steps are as follows:

[0120] 0.7354 g of the supramolecular hydrogel prepared in Example 1 was added to 0.8 kg of cadmium-contaminated soil, and Amaranthus chinensis seedlings were transplanted at a plant density of 50 plants / m 2 , so that the supramolecular hydrogel is dispersed in the rhizosphere of the plant and cultured for 40 days. The plant restoration without adding supramolecular hydrogel is used as a control. The cadmium concentration of the soil before and after restoration is determined according to the national standard GB / T17141-1997, and the cadmium removal rate is calculated. The results are shown in Tables 3 and 4.

[0121] Table 3 Concentration of cadmium ions before and after adsorption of supramolecular hydrogel in Example 1

[0122]

[0123] Table 4 Accumulation and translocation of Cd by grain amaranth after restoration

[0124]

[0125] According to Tables 3 and 4, it can be seen that the supramolecular hydrogel provided by the present invention has the function of controlled release of plant hormones, cooperates with plant remediation, and effectively removes cadmium ions in the soil. The removal rate of heavy metal ions in the soil is above 40% after 40 days.

[0126] From the above examples, it can be seen that the supramolecular hydrogel provided by the present invention has the function of controllable release of plant hormones, and synergistically realizes the removal of heavy metal ions with plant remediation, with high environmental remediation efficiency. The soil heavy metal ion removal rate is above 40% after 40 days.

[0127] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A supramolecular hydrogel, characterized in that: The building blocks of the supramolecular hydrogel include carboxymethyl beta-cyclodextrin and amino clay that interacts with the carboxymethyl beta-cyclodextrin via electrostatic force.

2. The supramolecular hydrogel according to claim 1, characterized in that The mass ratio of the carboxymethyl beta-cyclodextrin to amino clay is 30-40:19-32.

3. The supramolecular hydrogel according to claim 1 or 2, characterized in that The building blocks of the supramolecular hydrogel further include plant hormones; the plant hormones are contained in the cavity of the carboxymethyl beta-cyclodextrin.

4. The supramolecular hydrogel according to claim 3, characterized in that The mass ratio of the carboxymethyl beta-cyclodextrin to the plant hormone is 1139:14-138.

5. The method for preparing the supramolecular hydrogel according to any one of claims 1 to 4, characterized in that: The following steps are involved: mixing carboxymethyl-β-cyclodextrin and the first water to obtain a stock solution; The stock solution, amino clay and second water are mixed and coagulated to obtain the supramolecular hydrogel.

6. The preparation method according to claim 5, characterized in that The molar volume ratio of the carboxymethyl-β-cyclodextrin to the first water is 10 mmol: (9-12) mL; the mass volume ratio of the amino clay to the stock solution is (0.3-0.4) g: (0.15-0.25) mL; the volume ratio of the stock solution to the second water is 0.15-0.25:1; and the molar concentration of the stock solution is 0.8-1.1 mol / L.

7. The preparation method according to claim 5, characterized in that After the coagulation, the product is allowed to stand and then freeze-dried; the freeze-drying comprises a pre-cooling stage and a drying stage in sequence; The temperature of the pre-cooling stage is not higher than -40°C, and the pre-cooling time is 1 to 1.5 hours; The temperature of the drying stage is -70 to -50°C, and the heat preservation and drying time is 48 to 72 hours.

8. The preparation method according to claim 5, characterized in that The building blocks of the supramolecular hydrogel further include plant hormones, and the preparation method of the supramolecular hydrogel comprises the following steps: mixing carboxymethyl-β-cyclodextrin, the plant hormone, and the first water to obtain a stock solution; The stock solution, amino clay and second water are mixed and coagulated to obtain the supramolecular hydrogel.

9. The preparation method according to claim 8, characterized in that The molar ratio of the carboxymethyl-β-cyclodextrin to the plant hormone is 10:1-10.

10. Use of the supramolecular hydrogel according to any one of claims 1 to 4 or the supramolecular hydrogel prepared by the method according to any one of claims 5 to 9 in removing heavy metals from soil.

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