阅读说明：本技术 一种用于微生物矿化的胶结液及其制备方法 (Cementing liquid for microbial mineralization and preparation method thereof ) 是由 胡俊 熊明 于 2021-07-16 设计创作，主要内容包括：本发明提供一种用于微生物矿化的胶结液及其制备方法,该胶结液含有氯化钙、尿素、氯化钠、大豆蛋白胨、生蚝壳粉、菠萝蜜籽粉、龙眼叶粉、葡萄糖基甜菊糖、椰子油酰胺丙基甜菜碱和水。采用本发明胶结液应用于黏性土胶结,能够抑制菌液胶结液混合时发生即时生化反应而生产絮凝作用,为MICP的有效胶结提供可控的窗口期,使混合液均匀分布于土体一定深度范围内,而且提高24h时CaCO-(3)化学转化率,显著提升胶结效果,提高胶结后土样贯入端应力,显著提升胶结土体表层的饱和结构强度,提高胶结的均匀程度,改善坡面抗侵蚀能力。(The invention provides a cementing liquid for microbial mineralization and a preparation method thereof. The cementing liquid is applied to cementing of cohesive soil, can inhibit the instant biochemical reaction generated during the mixing of the bacterial liquid cementing liquid to produce flocculation, provides a controllable window period for the effective cementing of MICP, ensures that the mixed liquid is uniformly distributed in a certain depth range of the soil body, and improves CaCO at 24h 3 The chemical conversion rate obviously improves the cementing effect, improves the stress of the soil sample injection end after cementing, obviously improves the saturated structural strength of the surface layer of the cemented soil body, improves the cementing uniformity and improves the erosion resistance of the slope.)

1. A cementing liquid for microbial mineralization is characterized by comprising 55-111g of calcium chloride, 30-60g of urea, 0.4-0.5g of sodium chloride, 1.2-1.8g of soybean peptone, 0.5-0.8g of oyster shell powder, 0.8-1.2g of jackfruit seed powder, 1.3-1.5g of longan leaf powder, 0.8-1g of glucose-based stevioside, 0.5-1.0g of cocamidopropyl betaine and the balance of water per liter.

2. The microbial mineralization cementing liquid of claim 1, wherein the cementing liquid comprises 111g of calcium chloride, 60g of urea, 0.45g of sodium chloride, 1.5g of soybean peptone, 0.7g of fresh oyster shell powder, 1.0g of jackfruit seed powder, 1.4g of longan leaf powder, 0.9g of glucose-based stevioside, 0.8g of cocamidopropyl betaine and the balance of water per liter.

3. The microbial mineralization cementing liquid of claim 1, wherein the oyster shell powder has a mesh size of 30-50 mesh.

4. The microbial mineralization cementing liquid of claim 1, wherein the mesh size of the jackfruit seed powder is 80-120 mesh.

5. The microbial mineralization cementing liquid of claim 1, wherein the longan leaf powder has a mesh size of 60-80 mesh.

6. The method for preparing a microbial mineralization cementing liquid according to any one of claims 1 to 5, wherein calcium chloride is added into water, oyster shell powder, jackfruit seed powder and longan leaf powder are added, and stirring is carried out at 1800-2000 rpm for 0.6-0.8 h; adding sodium chloride, soybean peptone and glucose-based stevioside, and stirring at 1200-1300 rpm for 1.2-1.5 h; and finally, adding urea and cocamidopropyl betaine, and adjusting the pH value to 4.5-5.5 to prepare the target cementing liquid.

7. The method of claim 6, wherein the jackfruit seed powder is prepared from jackfruit seeds by pre-freezing, drying, pulverizing and sieving.

8. The method for preparing the microbial mineralization cementing liquid according to claim 7, wherein the pre-freezing condition is that the jack fruit seeds are pre-frozen at-15 to-20 ℃ for 2 to 3 hours.

9. The preparation method of the cementing liquid for microbial mineralization according to claim 6 or 8, wherein the temperature in the stirring process is controlled to be 5-10 ℃.

Technical Field

The invention relates to the field of cementing liquids, in particular to a cementing liquid for microbial mineralization and a preparation method thereof.

Background

The MICP (microbial induced calcium carbonate deposition) technology has the characteristics of simple construction, environmental friendliness and the like. Due to poor permeability of cohesive soil, cells of the microorganism cannot migrate within pores that are too small in size. Adding cementing liquid into the MICP technology bacteria liquid to produce CaCO for bacteria₃The crystals provide a source of urea and calcium (CaCl)₂). The problems of rapid flocculation, pore blockage and the like easily occur after the bacteria liquid and the cementing liquid are contacted in the traditional single-phase cementing process, so that the mixed liquid of the bacteria liquid and the cementing liquid is difficult to be uniformly distributed in a certain depth range of a soil body, the cementing effect is poor, and the application of the MICP technology to cohesive soil is not facilitated.

Disclosure of Invention

In view of the above, the present invention provides a cementing liquid for microbial mineralization and a preparation method thereof, which solve the above technical problems.

The technical scheme of the invention is realized as follows:

a cementing liquid for microorganism mineralization contains 55-111g of calcium chloride, 30-60g of urea, 0.4-0.5g of sodium chloride, 1.2-1.8g of soybean peptone, 0.5-0.8g of oyster shell powder, 0.8-1.2g of jackfruit seed powder, 1.3-1.5g of longan leaf powder, 0.8-1g of glucose-based stevioside, 0.5-1.0g of cocamidopropyl betaine and the balance of water per liter.

Further, each liter contains 111g of calcium chloride, 60g of urea, 0.45g of sodium chloride, 1.5g of soybean peptone, 0.7g of oyster shell powder, 1.0g of jack fruit seed powder, 1.4g of longan leaf powder, 0.9g of glucose-based stevioside, 0.8g of cocamidopropyl betaine and the balance of water.

Furthermore, the mesh number of the oyster shell powder is 30-50 meshes.

Furthermore, the mesh number of the jackfruit seed powder is 80-120 meshes.

Furthermore, the mesh number of the longan leaf powder is 60-80 meshes.

The preparation method of the cementing liquid comprises the steps of adding calcium chloride into water, adding oyster shell powder, jackfruit seed powder and longan leaf powder, and stirring at 1800-2000 rpm for 0.6-0.8 h; adding sodium chloride, soybean peptone and glucose-based stevioside, and stirring at 1200-1300 rpm for 1.2-1.5 h; and finally, adding urea and cocamidopropyl betaine, and adjusting the pH value to 4.5-5.5 to prepare the target cementing liquid.

Further, the jackfruit seed powder is prepared by pre-freezing, drying, crushing and sieving jackfruit seeds. Furthermore, the pre-freezing condition is that the jack fruit seeds are pre-frozen for 2 to 3 hours at a temperature of between 15 ℃ below zero and 20 ℃ below zero.

Further, the temperature in the stirring process is controlled to be 5-10 ℃.

Compared with the prior art, the invention has the beneficial effects that:

the invention adopts calcium chloride, urea, sodium chloride and soybean peptone to combine oyster shell powder, jackfruit seed powder and longan leaf powderAnd adding glucose-based stevioside and cocamidopropyl betaine, preferably selecting a certain proportion to prepare a cementing liquid, applying to cohesive soil cementation, inhibiting instant biochemical reaction when the bacterial liquid cementing liquid is mixed to produce flocculation, delaying flocculation time, solving the problems of rapid flocculation, pore blockage and the like after the bacterial liquid and the cementing liquid are contacted in the traditional single-phase cementing process, providing a controllable window period for effective cementation of MICP, uniformly distributing the mixed liquid in a certain depth range of a soil body, and increasing CaCO for 24h₃The chemical conversion rate obviously improves the cementing effect, improves the stress of the soil sample injection end after cementing, obviously improves the saturated structural strength of the surface layer of the cemented soil body, improves the cementing uniformity and improves the erosion resistance of the slope.

Detailed Description

In order to better understand the technical content of the invention, specific examples are provided below to further illustrate the invention.

The experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified.

The materials, reagents and the like used in the examples of the present invention can be obtained commercially without specific description.

Example 1

A cementing liquid for microbial mineralization contains 111g of calcium chloride, 60g of urea, 0.45g of sodium chloride, 1.5g of soybean peptone, 0.7g of oyster shell powder, 1.0g of jackfruit seed powder, 1.4g of longan leaf powder, 0.9g of glucose-based stevioside, 0.8g of cocamidopropyl betaine and the balance of water per liter.

The preparation method of the cementing liquid comprises the following steps:

(1) raw material treatment

Grinding raw oyster shells, and sieving with a 30-mesh sieve to obtain the raw oyster shell powder.

Pulverizing folium longan, and sieving with 60 mesh sieve to obtain longan leaf powder.

Taking jackfruit seeds, pre-freezing for 2 hours at-15 ℃, drying, crushing, and sieving with a 80-mesh sieve to obtain the jackfruit seed powder.

(2) Preparation of the cementing fluid

Respectively taking the raw materials according to the weight, firstly adding calcium chloride into water, adding oyster shell powder, jackfruit seed powder and longan leaf powder, and mechanically stirring for 0.6h at the rotating speed of 2000 rpm; then adding sodium chloride, soybean peptone and glucose-based stevioside, and mechanically stirring for 1.2h at the rotating speed of 1300 rpm; and finally, adding urea and cocamidopropyl betaine, adjusting the pH value to 4.5, and controlling the temperature to be 5-10 ℃ in the stirring process to prepare the target cementing liquid.

Example 2

A cementing liquid for microbial mineralization contains 55g of calcium chloride, 30g of urea, 0.4g of sodium chloride, 1.2g of soybean peptone, 0.5g of oyster shell powder, 1.2g of jackfruit seed powder, 1.5g of longan leaf powder, 1g of glucose-based stevioside, 0.5g of cocamidopropyl betaine and the balance of water per liter. The preparation procedure was in accordance with example 1.

Example 3

A cementing liquid for microbial mineralization contains 111g of calcium chloride, 60g of urea, 0.5g of sodium chloride, 1.8g of soybean peptone, 0.8g of oyster shell powder, 1.2g of jackfruit seed powder, 1.3g of longan leaf powder, 0.8g of glucose-based stevioside, 1.0g of cocamidopropyl betaine and the balance of water per liter. The preparation procedure was in accordance with example 1.

Example 4

A cementing liquid for microbial mineralization contains 111g of calcium chloride, 60g of urea, 0.45g of sodium chloride, 1.5g of soybean peptone, 0.7g of oyster shell powder, 1.0g of jackfruit seed powder, 1.4g of longan leaf powder, 0.9g of glucose-based stevioside, 0.8g of cocamidopropyl betaine and the balance of water per liter.

The preparation method of the cementing liquid comprises the following steps:

(1) raw material treatment

Grinding the fresh oyster shell, and sieving with a 50-mesh sieve to obtain the fresh oyster shell powder.

Pulverizing folium longan, and sieving with 80 mesh sieve to obtain longan leaf powder.

Taking jackfruit seeds, pre-freezing for 3 hours at the temperature of 20 ℃ below zero, drying, crushing, and sieving with a 120-mesh sieve to obtain the jackfruit seed powder.

(2) Preparation of the cementing fluid

Respectively taking the raw materials according to the weight, firstly adding calcium chloride into water, adding oyster shell powder, jackfruit seed powder and longan leaf powder, and mechanically stirring for 0.8h at the rotation speed of 1800 rpm; then adding sodium chloride, soybean peptone and glucose-based stevioside, and mechanically stirring for 1.5h at the rotating speed of 1200 rpm; and finally, adding urea and cocamidopropyl betaine, adjusting the pH value to 5.5, and controlling the temperature to be 5-10 ℃ in the stirring process to prepare the target cementing liquid.

Comparative example 1

And (3) mixing 111g of calcium chloride, 60g of urea, 0.45g of sodium chloride and 1.5g of soybean peptone, and adding water to a constant volume of 1L to obtain the cementing liquid.

Comparative example 2

The formula of the cementing liquid is as follows: each liter of the fertilizer contains 111g of calcium chloride, 60g of urea, 0.45g of sodium chloride, 1.5g of soyapeptone, 0.1g of oyster shell powder, 0.5g of jackfruit seed powder, 0.5g of longan leaf powder, 0.5g of glucose-based stevioside, 0.1g of cocamidopropyl betaine and the balance of water. The preparation procedure was in accordance with example 1.

Comparative example 3

The formula of the cementing liquid is as follows: each liter of the fertilizer contains 111g of calcium chloride, 60g of urea, 0.45g of sodium chloride, 1.5g of soyapeptone, 1.0g of oyster shell powder, 1.5g of jack fruit seed powder, 2.0g of longan leaf powder, 1.5g of glucose-based stevioside, 1.5g of cocamidopropyl betaine and the balance of water. The preparation procedure was in accordance with example 1.

Comparative example 4

The main difference from example 1 is that the seeds of jack fruit were selected without pre-freezing. Taking jackfruit seeds, directly crushing the jackfruit seeds, and then sieving the jackfruit seeds with a 80-mesh sieve to obtain the jackfruit seed powder.

Comparative example 5

The main difference from the embodiment 1 is that the temperature during the stirring process is not controlled to be 5-10 ℃, and the temperature during the stirring process is 25-30 ℃.

Test examples

(1) Selection of cohesive soil

This experiment adopted Hainan red clay as the object of modification.

(2) Strain selection

Bady spore stack ball selected for the testAnd (5) bacteria. The strain is stored in a refrigerator at 4 ℃ by plate coating, and is periodically activated to keep the activity. The formulation of the medium (250mL) used in this experiment was Tris base 3.9g, yeast extract 5.0g, (NH)₄)₂SO₄2.5 g. Taking activated bacteria liquid (OD) for multiple rounds₆₀₀About 1.2), inoculated into 250mL of medium with a pipette at 10 mL. Culturing bacteria at 30 deg.C and 150rpm for 24 hr with constant temperature shaking incubator, and measuring OD of bacteria liquid with spectrophotometer₆₀₀(Unit OD)₆₀₀The value corresponds to about 8.6X 10 per ml⁷Individual bacteria) value of about 1.2. The urease activity of the bacterial solution used in this test was about 3.1mM urea.min^－1。

(3) Cement to window period and CaCO₃Influence of chemical conversion

Study of the examples and the production of CaCO by bacteria in cement solutions with different ratios₃The influence of the crystal efficiency is realized by mixing the cementing liquid and the bacterial liquid (sporosarcina pasteurii) (the mixing volume ratio is 30 ml: 30ml), and the influence of the cementing liquid on the chemical conversion rate in the MICP reaction process is researched in a liquid environment.

In the test, the cementing solution of the examples and the comparative examples was mixed with the bacterial solution having a pH of 5.0, and the mixture was left to stand for 24 hours, centrifuged, filtered, and the precipitate was washed and dried. And (5) observing the flocculation condition in the standing process. And by formation of CaCO₃Mass conversion of the crystals to chemical conversion.

CaCO₃Chemical conversion means conversion to CaCO₃Precipitated Ca²⁺The amount of Ca in the solution before the reaction²⁺The amount of (c).

(4) Preparation of soil samples

Firstly, drying and crushing red clay under the original state, sieving the red clay by a 2mm sieve, weighing 750.0g of air-dried soil (the initial water content is 3.7 percent), filling the air-dried soil into a cylindrical mould (the inner diameter is 10.0cm, the height is 8.0cm) in a layering manner, wherein the final height of a soil sample is 6cm, and the dry density is 1.5g cm^－3. The bottom of the mould is perforated for draining water, and meanwhile, double layers of gauze are padded to prevent soil particles from flowing out. Adding water to saturate the sample, then naturally drying the sample, repeating 5 times to simulate the natural dry-wet cycle, and aiming at enabling the initial structural state of the soil sample to be close to selfBut then the earth is surfaced. The deformation and mechanical properties of the remolded soil sample prepared indoors can basically reach a relatively stable state after 3-5 times of dry-wet circulation. According to the above-described operation, the sample can be repeatedly prepared.

(5) Preparation of cemented soil samples

And (3) adopting a single-phase cementing process, reducing the pH value of a bacterial liquid (sporosarcina pasteurii) to 5.0 by utilizing a 1.0M HCl solution, mixing with the cementing liquid, quickly spraying the mixed solution onto the surface of the sample, allowing the sample to naturally infiltrate, standing for one week, and naturally air-drying at room temperature to obtain the cemented soil sample.

Remarking: the spraying treatment time of each sample is 10-15 min, the sample is in an unsaturated state before being treated, and effusion is not formed on the surface of the sample all the time in the spraying treatment process.

(6) Structural strength test of cemented soil sample

The soil samples treated by different cementing liquids of examples and comparative examples are subjected to a penetration test by using an ultramicro penetrometer SMP-1, and the structural strength of the soil body is reflected by the end resistance of a probe in the process of penetrating into the soil body. Before the penetration, the bottom of the mold is opened to allow water to penetrate from bottom to top, so as to saturate the sample. Different points (more than 2cm apart) are selected for each sample to carry out 3 times of penetration tests, the penetration depth is 20mm each time, and then the results are averaged.

The results show that the cementing liquid of the embodiments 1 to 4 of the invention can inhibit the instant biochemical reaction during the mixing of the bacterial liquid cementing liquid to produce flocculation, delay the flocculation occurrence time, provide a controllable window period for the effective cementation of MICP, and improve CaCO at 24h₃The chemical conversion rate improves the stress of the injection end of the cemented soil sample, obviously improves the saturated structural strength of the surface layer of the cemented soil body, and improves the uniformity of cementation.

The components of the cementing liquid formula are not adopted in the comparative example 1, the components of the cementing liquid formula are not adopted in the comparative examples 2 to 3, the effect is obviously reduced, the flocculation time is fast, the chemical conversion rate of CaCO3 is reduced, the average stress value of the soil sample injection end is reduced after 24 hours, and the cementing is not uniform.

In the comparative example 4, the jack fruit seeds are not pre-frozen, the temperature is not controlled to be 5-10 ℃ in the stirring process of the comparative example 5, the temperature is controlled to be 25-30 ℃ in the stirring process, and CaCO is used₃The chemical conversion rate is reduced, and the average value of the stress at the penetrating end of the soil sample is also reduced after 24 hours.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.