Method for solidifying soil body through plant carbonic anhydrase

Abstract

The invention discloses a method for solidifying a soil body through plant carbonic anhydrase, and belongs to the technical field of rock-soil body improvement. The method for solidifying the soil body through the plant carbonic anhydrase comprises the following steps that an alkaline buffer solution is sprayed on the surface of the soil body, and an I-stage solidified soil body is obtained; spraying the mixed solution A on the surface of the I-stage solidified soil body to obtain a II-stage solidified soil body; the components in the mixed solution A comprise a soluble salt solution capable of forming a precipitate with carbonate radicals and a plant carbonic anhydrase crude extracting solution; spraying the mixed solution B and the carbon dioxide solution on the surface of the II-stage solidified soil body to obtain an III-stage solidified soil body; the mixed solution B comprises a plant carbonic anhydrase crude extract and a surfactant. According to the method, grouting is not needed, a large amount of carbon dioxide cannot be discharged into the atmosphere, and the problems that an existing curing method is large in grouting difficulty and large in environmental influence are solved.

Description

Technical Field

[0001] The invention relates to the technical field of rock and soil improvement, and in particular to a method for solidifying soil using plant carbonic anhydrase. Background Art

[0002] In engineering projects, it is often necessary to artificially improve rock and soil bodies to meet the requirements of strength, bearing capacity, permeability, etc., and sometimes it is also necessary to repair cracked or deteriorated concrete in some special parts. The commonly used method is to inject or spray cementitious materials into the treated medium. Commonly used cementitious materials are mainly cement, and there are some chemical cementitious materials such as water glass and polymer materials. These cementitious materials are highly viscous, and it is difficult to inject them into underground rock and soil bodies and deteriorated concrete. They also require the help of large-scale machinery to complete. In addition, some chemical cementitious materials have a relatively large impact on the environment and their own stability is also poor. At the same time, the production of these cementitious materials requires the emission of a large amount of carbon dioxide into the atmosphere, which is not conducive to environmental protection. Therefore, it is urgent to find a method for soil solidification that is easy to use, has little environmental impact, and has good stability. Summary of the invention

[0003] The object of the present invention is to provide a method for solidifying soil by plant carbonic anhydrase, to solve the problems existing in the above-mentioned prior art. The method for solidifying soil by plant carbonic anhydrase of the present invention is a method for realizing rock and soil improvement or concrete repair by utilizing the biochemical process existing in nature, without the need for grouting and without discharging a large amount of carbon dioxide into the atmosphere, thus overcoming the problems that the grouting difficulty and environmental impact of the existing solidification method are large. And the solidification method of the present invention has a certain carbon absorption function (the plant carbonic anhydrase can absorb and utilize carbon dioxide during the mineralization process).

[0004] To achieve the above object, the present invention provides the following scheme: a method for solidifying soil using plant carbonic anhydrase, comprising the following steps:

[0005] (1) spraying an alkaline buffer solution on the surface of the soil to obtain a first-stage solidified soil;

[0006] Spraying alkaline buffer on the surface of the soil can optimize the reaction environment in the soil, making it an environment that is conducive to the induction of mineralization by plant carbonic anhydrase;

[0007] (2) spraying a mixed solution A on the surface of the first-stage solidified soil to obtain a second-stage solidified soil; the components of the mixed solution A include a soluble salt solution that can form a precipitate (carbonate mineral) with carbonate ions and a crude extract of plant carbonic anhydrase;

[0008] Spraying the mixed solution A can optimize the medium treatment range (in order to improve the problem of thin and uneven thickness caused by the spraying method, on the basis of changing the environment of the soil, by spraying the mixed solution A, on the one hand, the water content of the soil is increased, the depth of solution penetration is increased, and on the other hand, the alkaline solution of the first step is driven deep into the soil, forming an environment in which the lower part is more alkaline than the upper part, so that the calcium carbonate in the lower part is formed earlier than the upper part, improving the uniformity) and initially forming a mineralized cementation structure;

[0009] (3) Spraying a mixed solution B and a carbon dioxide solution on the surface of the stage II solidified soil to obtain a stage III solidified soil; the components of the mixed solution B include a crude plant carbonic anhydrase extract and a surfactant.

[0010] Spraying the mixed solution B can accelerate the reaction rate and efficiency, further forming a mineralized cementation structure to enhance the curing effect.

[0011] Furthermore, the method also includes repeating the process (3) to further increase the strength of the soil.

[0012] The introduction of gas containing carbon dioxide or the use of carbon dioxide in the air can allow the plant carbonic anhydrase to induce the mineralization reaction to continue, further increasing the strength of the soil.

[0013] Furthermore, the pH of the buffer solution is 9-11; the soil body includes aeolian sand; the buffer solution includes Hepes and / or Tris; and 1-2 L of the buffer solution is sprayed per square meter of the soil surface.

[0014] Furthermore, the concentration of the ions that can form precipitation with carbonate in the soluble salt solution is 3 to 12 mol / L;

[0015] The soluble salt in the soluble salt solution includes one or more of calcium chloride, calcium nitrate and calcium acetate.

[0016] Furthermore, the method for preparing the crude plant carbonic anhydrase extract comprises the following steps:

[0017] The plant tissue containing the plant carbonic anhydrase is crushed and then filtered to obtain a coarse filtrate;

[0018] Adding water and pH buffer solution to the crude filtrate, adjusting the pH to 8-10, and centrifuging to obtain the crude extract of the plant carbonic anhydrase;

[0019] The ratio of the plant tissue to the crude plant carbonic anhydrase extract is 5-80 g / 1L; the enzyme activity of the crude plant carbonic anhydrase extract is 20-60 U / mL.

[0020] Furthermore, the plant tissue includes one or more of food crop leaves, weed leaves and vegetable leaves.

[0021] Furthermore, the food crop leaves include one or more of corn, sorghum and rice leaves; the vegetable leaves include one or more of spinach, water spinach, rapeseed and Chinese cabbage leaves.

[0022] Furthermore, the crushing method includes mechanical crushing or ultrasonic crushing.

[0023] Furthermore, the volume ratio of the soluble salt solution and the crude plant carbonic anhydrase extract in the mixed solution A is 10 to 20:1;

[0024] Spray 2 to 4 L of mixed solution A on the surface of each square meter of the first-stage solidified soil.

[0025] Further, the carbon dioxide solution is a carbon dioxide saturated solution;

[0026] The volume ratio of the carbon dioxide solution to the crude plant carbonic anhydrase extract in the mixed solution B is 5 to 10:1;

[0027] The volume of the surfactant accounts for 0.025-0.25% of the total volume of the carbon dioxide solution and the plant carbonic anhydrase crude extract in the mixed solution B.

[0028] Furthermore, 2 to 4 L of the mixed solution B and the carbon dioxide solution are sprayed on the surface of the stage II solidified soil per square meter.

[0029] Furthermore, the method for preparing the carbon dioxide solution comprises: introducing a gas containing carbon dioxide into water until the water is saturated with carbon dioxide.

[0030] The crude plant carbonic anhydrase extract used in the soil solidification process of the present invention can undergo biochemical reactions, induce carbon dioxide and calcium ions to form carbonate crystals, cement soil particles, and improve soil strength. When used, different effects (different strengths) can be achieved through multiple treatments to achieve different purposes.

[0031] At the same time, when improving and reinforcing the soil surface, carbon dioxide in the atmosphere can be used as a reaction substrate to achieve the formation of carbonate crystals, thereby achieving the triple effects of carbon fixation, soil improvement and cost reduction.

[0032] The present invention discloses the following technical effects:

[0033] (1) The method of solidifying soil with plant carbonic anhydrase of the present invention is a method for improving rock and soil or repairing concrete by utilizing biochemical processes existing in nature, which does not require grouting and does not emit a large amount of carbon dioxide into the atmosphere, thus overcoming the problems of difficult grouting and large environmental impact in existing solidification methods. In addition, the solidification method of the present invention has a certain carbon absorption function (the plant carbonic anhydrase will absorb and utilize carbon dioxide during the mineralization process induced by the plant carbonic anhydrase).

[0034] (2) The method of solidifying soil with plant carbonic anhydrase of the present invention utilizes the principle of plant-induced mineralization, which is a biochemical reaction that exists naturally in nature. Compared with artificial injection of chemical cementitious materials, it is more stable and will not cause pollution to the environment.

[0035] (3) The method of solidifying soil with plant carbonic anhydrase of the present invention requires less reaction substrate, the reaction product is in crystalline form, and the amount of by-product salt after the reaction is terminated is small. Compared with other biological induction methods, it has less impact on the chemical environment of the soil itself and reduces the cost of use.

[0036] (4) The method of soil solidification using plant carbonic anhydrase of the present invention can utilize carbon dioxide in the atmosphere as a reaction substrate, so that the reaction can occur continuously without adding additional reaction substrate, and the carbon dioxide content in the atmosphere can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0038] Figure 1 Schematic diagram of the process of soil solidification using plant carbonic anhydrase. DETAILED DESCRIPTION

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0041] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0042] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0043] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0044] Example 1

[0045] A method for solidifying soil using plant carbonic anhydrase (a method for solidifying aeolian sand by inducing carbon dioxide mineralization using plant carbonic anhydrase):

[0046] (1) Prepare a Tris buffer solution with a pH of 9 and place it in a high-pressure spray pot until the dry density reaches 1.61 g / cm 3 d 50 =0.35mm, pH 8, and the surface of desert aeolian sand was sprayed. The amount of Tris buffer was 1L / m 2 The surface of desert aeolian sand is removed to obtain the first-stage solidified soil.

[0047] (2) Preparation of crude plant carbonic anhydrase extract (plant carbonic anhydrase extract): 40 g of waste spinach leaves were placed in a precooled crusher, and liquid nitrogen was quickly added to mechanically crush the cells. The cell-breaking solution was coarsely filtered through gauze; then poured into a 2L beaker, and 1L of pure water was added to the beaker. The pH of the solution was adjusted to 8 using Hepes buffer with a pH of 9, and then placed in a high-speed refrigerated centrifuge for refrigerated centrifugation at a speed of 12000 r / min and a temperature of 0 to 4°C for 15 minutes to obtain a crude plant carbonic anhydrase extract.

[0048] Determination of the activity of crude extract of plant carbonic anhydrase: Determined by pH meter method, the test environment is 0℃, one activity unit U=n×(t0 / t e-1), where n is the enzyme dilution multiple, t0 and t e The time taken by the dead enzyme and the live enzyme to reduce the saturated carbon dioxide solution from 8.3 to 7.5 respectively. After measurement, the activity of the obtained plant carbonic anhydrase crude extract was 60U / mL.

[0049] (3) Weigh 82.6 g of calcium chloride solution and dissolve it in 250 mL of pure water to prepare a 3 mol / L calcium chloride solution (soluble calcium salt solution).

[0050] (4) 25 mL of the crude plant carbonic anhydrase extract and 250 mL of the calcium chloride solution were mixed to obtain a mixed solution A.

[0051] Put the mixed solution A into a high-pressure spray pot and spray it on the surface of the first-stage solidified soil. The amount of mixed solution A is 2L / m 2 The surface of the first-stage solidified soil was left to stand for 3 days to obtain the second-stage solidified soil.

[0052] (5) Place 250 mL of pure water in a 500 mL beaker, connect one end of a thin tube to a carbon dioxide gas cylinder, and place the other end below the liquid surface of the pure water to aerate the pure water. Adjust the pressure regulating valve of the carbon dioxide gas cylinder so that the bubbles flow out in uniform small bubbles. During the aeration, the solution is placed in an ice bath at 0 to 4°C, and the aeration time is maintained at more than 30 minutes to obtain a carbon dioxide solution (i.e., a carbon dioxide saturated solution).

[0053] (6) taking 50 mL of the crude plant carbonic anhydrase extract, adding a surfactant thereto (the surfactant is Triton X-100, and the volume of the surfactant accounts for 0.1% of the total volume of the carbon dioxide solution and the crude plant carbonic anhydrase extract), and mixing well to obtain a mixed solution B;

[0054] After spraying the mixed solution B onto the surface of the II-stage solidified soil, quickly spray 250 mL of saturated carbon dioxide solution (the total amount of mixed solution B and carbon dioxide solution is 2 L / m 2 The surface of the II-stage solidified soil was left to stand for 7 days to obtain the III-stage solidified soil.

[0055] During the solidification period, the soil can absorb carbon dioxide from the air, which can enable the plant carbonic anhydrase-induced mineralization reaction to continue, further increasing the strength of the soil. Figure 1 .

[0056] The surface particles of the treated aeolian sand are cemented with the induced calcium carbonate crystals, and the surface strength is increased to more than 3 times that of the unreinforced soil (the surface strength of the untreated soil in this embodiment is about 18 kPa, and the surface strength is increased to about 60 kPa after being treated by the method of this embodiment. The surface strength of the soil can be further increased by continuing to increase the number of spraying of the mixed solution B and the carbon dioxide solution). In a humid state, the carbon dioxide in the air can be further absorbed for mineralization, and the effect can be further enhanced.

[0057] Comparative Example 1

[0058] (1) to (3) are the same as in Example 1.

[0059] (4) 25 mL of the crude plant carbonic anhydrase extract and 250 mL of the calcium chloride solution were mixed to obtain a mixed solution A.

[0060] (5) Same as Example 1.

[0061] (6) taking 50 mL of the crude plant carbonic anhydrase extract, adding a surfactant thereto (the surfactant is Triton X-100, and the volume of the surfactant accounts for 0.1% of the total volume of the carbon dioxide solution and the crude plant carbonic anhydrase extract), and mixing well to obtain a mixed solution B;

[0062] (7) 2 L of mixed solution A, 333 mL of mixed solution B and 1667 mL of saturated carbon dioxide solution were mixed and the pH was adjusted to 9. The mixture was then sprayed on the same area of ​​1 m2 as in Example 1. 2 The surface of desert aeolian sand was left to stand for 10 days.

[0063] The measured surface strength of the mixed spraying is not much different from that of Example 1 of the present invention. However, for the mixed spraying (Comparative Example 1), the average thickness of the reinforced soil is 1.0 cm, while the average thickness of the reinforced soil in Example 1 is 2.25 cm. In comparison, the method of Example 1 of the present invention can increase the thickness of the reinforced aeolian sand by more than 50%.

[0064] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for solidifying soil using plant carbonic anhydrase, characterized in that: The following steps are involved: Spray an alkaline buffer solution on the surface of the soil to obtain a first-stage solidified soil; Spraying mixed solution A on the surface of the first-stage solidified soil to obtain the second-stage solidified soil; the components of the mixed solution A include a soluble salt solution that can form a precipitate with carbonate ions and a crude extract of plant carbonic anhydrase; The mixed solution B and the carbon dioxide solution are sprayed on the surface of the stage II solidified soil to obtain the stage III solidified soil; the components in the mixed solution B include a crude plant carbonic anhydrase extract and a surfactant.

2. The method according to claim 1, characterized in that: The method further comprises the step of repeatedly spraying the mixed solution B and the carbon dioxide solution.

3. The method according to claim 1, characterized in that The pH of the buffer solution is 9-11; the soil body comprises aeolian sand; the buffer solution comprises Hepes and / or Tris; and 1-2 L of the buffer solution is sprayed on each square meter of the soil body surface.

4. The method according to claim 1, characterized in that: The concentration of the ions that can form precipitation with carbonate in the soluble salt solution is 3 to 12 mol / L; The soluble salt in the soluble salt solution includes one or more of calcium chloride, calcium nitrate and calcium acetate.

5. The method according to claim 1, characterized in that The method for preparing the crude plant carbonic anhydrase extract comprises the following steps: The plant tissue containing the plant carbonic anhydrase is crushed and then filtered to obtain a coarse filtrate; Adding water and pH buffer solution to the crude filtrate, adjusting the pH to 8-10, and centrifuging to obtain the crude extract of the plant carbonic anhydrase; The ratio of the plant tissue to the crude plant carbonic anhydrase extract is 5-80 g / L; the enzyme activity of the crude plant carbonic anhydrase extract is 20-60 U / mL.

6. The method according to claim 1, characterized in that The volume ratio of the soluble salt solution and the crude plant carbonic anhydrase extract in the mixed solution A is 10 to 20:1; Spray 2 to 4 L of mixed solution A on the surface of each square meter of the first-stage solidified soil.

7. The method according to claim 1, characterized in that The carbon dioxide solution is a carbon dioxide saturated solution; The volume ratio of the carbon dioxide solution to the crude plant carbonic anhydrase extract in the mixed solution B is 5 to 10:1; The volume of the surfactant accounts for 0.025-0.25% of the total volume of the carbon dioxide solution and the plant carbonic anhydrase crude extract in the mixed solution B.

8. The method according to claim 1, characterized in that Spray 2 to 4 L of mixed solution B and carbon dioxide solution on the surface of each square meter of the second-stage solidified soil.

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