A kind of agent for soil solidification treatment of polluted plants and its preparation method and application

Abstract

The present invention discloses a soil solidification treatment agent for a polluted plant, a preparation method thereof and an application thereof, wherein the soil solidification treatment agent for a polluted plant comprises, by weight, 5-55 parts of graphene oxide, 1-20 parts of melamine, 0.1-3 parts of epoxy compounds and 10-150 parts of solid waste powder. The stabilizer prepared by using graphene oxide, melamine, epoxy compounds and solid waste powder as raw materials contains a large number of active groups such as carboxyl and hydroxyl groups, has a strong adsorption effect on heavy metal ions, can effectively adjust the internal structure of the soil, and solidify the heavy metal ions, thereby improving the bearing capacity and stability of the soil.

Description

Technical Field

[0001] The present invention relates to the field of soil remediation, and in particular to a medicament for soil solidification treatment in a polluted plant, and a preparation method and application thereof. Background Art

[0002] With the relocation and reconstruction of electroplating plants, landfills, chemical plants and other enterprises, the soil in the original industrial sites has absorbed too many heavy metals or organic pollutants and needs to be repaired in time. In-situ fixation remediation technology is to add repair agents to the soil to adjust and change the physical and chemical properties of heavy metals in the soil, so that it produces a series of reactions such as precipitation, adsorption, ion exchange, humification and oxidation-reduction, thereby converting heavy metals into a form with relatively stable chemical properties, reducing its effective state content in the soil environment, and thus reducing the toxicity of heavy metal elements to animals and plants.

[0003] Patent CN108822860A discloses an in-situ passivation technology and application for composite heavy metal pollution in farmland soil, which can reduce residual metals in the soil by more than 90%. However, the raw materials for preparation include: superphosphate, calcium carbonate, sodium pyrophosphate, lignin, polyglutamic acid, zeolite, quicklime, potassium sodium tartrate, aminotri(methylenephosphonic acid) and other substances, and the raw materials for preparation are numerous.

[0004] Patent CN103302092A discloses a rapid passivation and repair process for soil heavy metal Cr, Cu, Pb, and Zn pollution. The soil is repaired by sodium metasilicate. The raw materials are simple, but the passivation strength of the repair agent is low. After 8 days of passivation, the content of metallic copper in the soil is only reduced by 18.5% (Example 1: (45.38-36.97) / 45.38=18.5%), and the content of metallic zinc in the soil is only reduced by 24.8% (Example 1: (14.83-11.15) / 14.83=24.8%).

[0005] How to prepare a repair agent with simple raw materials and good effect of solidifying heavy metal ions in soil is still a technical problem that urgently needs to be solved. Summary of the invention

[0006] In order to overcome the above-mentioned shortcomings, one of the purposes of the present invention is to provide a chemical for solidifying soil in polluted plants, which has simple raw materials for preparation, can effectively solidify heavy metal ions in the soil, and improves the bearing capacity and stability of the soil.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is: a chemical for solidifying and treating soil in a polluted plant, wherein the raw materials include, by weight: 5-55 parts of graphene oxide, 1-20 parts of melamine, 0.1-3 parts of epoxy compound, and 10-150 parts of solid waste powder.

[0008] Graphene oxide has a two-dimensional nanostructure, and its sheets have a large number of carboxyl, hydroxyl, and epoxy active groups, and have good hydrophilicity and excellent mechanical strength.

[0009] By adding graphene oxide and melamine, melamine with triazine rings is grafted on graphene oxide to obtain modified graphene oxide. The triazine ring structure macromolecular compound grafted on the modified graphene oxide has a large steric hindrance, which reduces the agglomeration and stacking of graphene oxide, is beneficial to the uniform dispersion of the carbon layer in the soil, avoids the generation of cracks caused by stress concentration, and improves the bearing capacity of the soil. Exemplarily, the graphene oxide is 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts or any two of them; the melamine is 1 part, 5 parts, 7 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts or any two of them.

[0010] An epoxy compound is added and grafted onto the modified graphene oxide. The modified graphene oxide acts as a hydrophilic end and is adsorbed on the surface of soil particles to destroy the water film. The long-chain alkyl of the epoxy compound acts as a hydrophobic end, effectively preventing water penetration, and synergizing the bonding and water absorption effects of the solid waste powder to jointly improve the cohesion of soil particles. Exemplarily, the epoxy compound is in a range of 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, or any two of them.

[0011] By adding the compounded solid waste powder, the pores inside the soil can be filled, and the graphene oxide can be connected to jointly optimize the internal structure of the soil and improve the soil bearing capacity. For example, the solid waste powder is 10 parts, 20 parts, 40 parts, 60 parts, 80 parts, 100 parts, 120 parts, 140 parts, 150 parts, or any two of them.

[0012] The stabilizer is prepared by using graphene oxide, melamine, epoxy compounds and solid waste powder as raw materials. The stabilizer contains a large number of active groups such as carboxyl and hydroxyl groups, which have a complexing effect on heavy metal ions to solidify heavy metal ions and improve soil stability.

[0013] Furthermore, the raw materials include, by weight: 9-45 parts of graphene oxide, 2-16 parts of melamine, 0.2-1.5 parts of epoxy compound, and 20-120 parts of solid waste powder.

[0014] Furthermore, the mass ratio of graphene oxide to melamine is 1:0.1-0.6.

[0015] Furthermore, the mass ratio of graphene oxide to melamine is 1:0.2-0.4.

[0016] Furthermore, the epoxy compound is a C5-C25 alkyl ethylene oxide.

[0017] Furthermore, the epoxy compound is a C10-C20 alkyl ethylene oxide.

[0018] Furthermore, the epoxy compound is at least one of 1,2-epoxydecane, 1,2-epoxydodecane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane, 1,2-epoxyoctadecane, and 1,2-epoxyeicosane.

[0019] Furthermore, the solid waste powder is at least one of expansive soil, steel slag, calcite, fly ash, magnesium slag and lime.

[0020] Furthermore, the solid waste powder is a mixture of expansive soil, steel slag and calcite.

[0021] Furthermore, the mass ratio of expansive soil, steel slag and calcite is 1:(0.1-1.3):(0.1-1.0).

[0022] The specific ratio of solid waste powder can balance the relationship between soil expansion and contraction and strength improvement, thereby improving soil stability. Exemplarily, the mass ratio of steel slag to calcite is 1:0.1:0.1, 1:0.1:0.5, 1:0.1:1.0, 1:0.5:0.1, 1:0.5:0.5, 1:1.0:0.1, 1:1.0:0.5, 1:1.0:1.0, 1:1.3:1.0 or a range consisting of any two of them.

[0023] Furthermore, the mass ratio of expansive soil, steel slag and calcite is 1:(0.5-1.0):(0.2-0.5).

[0024] Furthermore, the average particle size of the expansive soil is 200-400 microns.

[0025] Preferably, the average particle size of the expansive soil is 250-350 microns.

[0026] Furthermore, the average particle size of the steel slag is 160-270 microns.

[0027] Preferably, the average particle size of the steel slag is 180-230 microns.

[0028] Furthermore, the average particle size of the calcite is 180-300 microns.

[0029] Preferably, the average particle size of calcite is 200-260 microns.

[0030] Another aspect of the present invention provides a method for preparing the above-mentioned agent for solidifying soil in a polluted plant, comprising the following steps:

[0031] S1, dissolving melamine in water to obtain a melamine aqueous solution; dispersing graphene oxide in water, fully stirring, heating, adding the melamine aqueous solution, stirring, filtering, washing, and drying to obtain modified graphene oxide;

[0032] S2, adding the modified graphene oxide and the epoxy compound into ethanol, stirring, filtering, washing, and drying to obtain a precursor;

[0033] S3, mixing the precursor with the solid waste powder, physically grinding them, and obtaining a stabilizer.

[0034] Furthermore, the preparation method of the stabilizer comprises the following steps:

[0035] S1. Dissolve 1-20 parts of melamine in 100-300 parts of hot water to obtain a melamine aqueous solution; then disperse 5-55 parts of graphene oxide in 100-300 parts of water, stir thoroughly for 0.5-1h, heat to 50-100°C, add the melamine aqueous solution, stir for 1-3h, filter, wash and dry to obtain modified graphene oxide.

[0036] S2. Add the modified graphene oxide and 0.1-3 parts of epoxy compound to 300-500 parts of ethanol in sequence, stir at 60-90° C. for 2-6 hours, filter, wash and dry to obtain a precursor.

[0037] S3. Mix the precursor with 10-150 parts of solid waste powder, and physically grind for 0.5-2h to obtain a stabilizer.

[0038] In another aspect, the present invention provides the use of the above-mentioned agent for solidifying polluted soil in a polluted plant, which is used for stabilizing the contaminated soil in the polluted plant.

[0039] During the application of the stabilizer, the mass percentage of the stabilizer in the contaminated soil is 1-10%.

[0040] Preferably, the mass percentage of the stabilizer to the contaminated soil is 3-8%.

[0041] The beneficial effects of the present invention are:

[0042] 1) A stabilizer prepared with graphene oxide, melamine, epoxy compounds, and solid waste powder as raw materials. The stabilizer contains a large number of active groups such as carboxyl and hydroxyl groups, which have a complexing effect on heavy metal ions to solidify heavy metal ions, thereby improving the stability of the soil.

[0043] 2) Graphene oxide is modified with melamine, and melamine with triazine rings is grafted onto graphene oxide to obtain modified graphene oxide. The exfoliation degree of the layer structure of graphene oxide becomes higher, providing more reactive sites for the system to form complexes with heavy metal ions in the soil, thereby achieving the effect of solidifying polluted ions. The triazine ring structure macromolecular compound grafted with modified graphene oxide has a large steric hindrance, which not only reduces the aggregation and stacking of graphene oxide, but also effectively improves the dispersion of the carbon layer in the soil, thereby optimizing the uniformity of soil stress, avoiding the generation of cracks caused by stress concentration, and improving the bearing capacity of the soil.

[0044] 3) Epoxy compounds are introduced and grafted onto modified graphene oxide. The modified graphene oxide bonded to it acts as the hydrophilic end and is adsorbed on the surface of soil particles to destroy the water film. The alkyl long chain acts as the hydrophobic end to effectively prevent water penetration, and synergistically produces the bonding effect and water absorption effect of the solid waste powder to jointly improve the cohesion of soil particles.

[0045] 4) The addition of solid waste powder, on the one hand, can fill the internal pores of the soil and bond with the carboxyl groups on the modified graphene oxide to form an internal network structure with a higher degree of cross-linking, thereby jointly optimizing the internal structure of the soil and improving the soil bearing capacity; on the other hand, the viscosity generated by the solid waste powder after absorbing water helps to increase the degree of aggregation between the soil, thereby improving the soil density; on the third hand, the solid waste powder can fix heavy metal ions in the soil through ion exchange, chemical coordination and other methods to improve soil stability.

[0046] 5) The specific proportion of solid waste powder can well balance the relationship between soil expansion and contraction and strength improvement, and synergistically modify graphene oxide and epoxy compounds to jointly improve soil bearing capacity and stability. DETAILED DESCRIPTION

[0047] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0048] Except as shown in the operating examples or otherwise indicated, all numbers used in the specification and claims to indicate the amount of ingredients, physicochemical properties, etc. are understood to be adjusted by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters listed in the above specification and the attached claims are approximate values, and those skilled in the art can use the teachings disclosed herein to seek to obtain the desired properties and appropriately change these approximate values. The use of numerical ranges expressed as endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0049] One embodiment of the present invention provides a method for preparing a soil solidification agent for a polluted plant, which specifically comprises the following steps:

[0050] S1. Dissolve 1-20 parts of melamine in 100-300 parts of hot water to obtain a melamine aqueous solution; then disperse 5-55 parts of graphene oxide in 100-300 parts of water, stir thoroughly for 0.5-1h, heat to 50-100°C, add the melamine aqueous solution, stir for 1-3h, filter, wash and dry to obtain modified graphene oxide.

[0051] In some embodiments, the mass ratio of graphene oxide to melamine is 1:0.1-0.6.

[0052] In some embodiments, the mass ratio of graphene oxide to melamine is 1:0.2-0.4.

[0053] Graphene oxide has a two-dimensional nanostructure, and its sheets have a large number of carboxyl, hydroxyl, and epoxy active groups, and have good hydrophilicity and excellent mechanical strength.

[0054] Graphene oxide is modified with melamine to obtain modified graphene oxide. The degree of exfoliation of the graphene oxide layer structure becomes higher, providing more reactive sites for the system to form complexes with heavy metal ions in the soil, thereby achieving the effect of solidifying heavy metal ions. The triazine ring structure macromolecular compound grafted on the modified graphene oxide has a large steric hindrance, which not only reduces the aggregation and stacking of graphene oxide, but also effectively improves the dispersion of the carbon layer in the soil, thereby optimizing the uniformity of soil stress and improving soil bearing capacity.

[0055] S2. Add the modified graphene oxide prepared in step S1 and 0.1-3 parts of epoxy compound to 300-500 parts of ethanol in sequence, stir at 60-90° C. for 2-6 hours, filter, wash and dry to obtain a precursor.

[0056] Epoxide compounds are introduced, and the modified graphene oxide bonded to them acts as the hydrophilic end, which is adsorbed on the surface of soil particles to destroy the water film. The alkyl long chain acts as the hydrophobic end, which effectively prevents water penetration and synergizes the bonding and water absorption effects produced by the solid waste powder, thereby improving the cohesion of soil particles.

[0057] In some embodiments, the epoxy compound is a C5-C25 alkyl ethylene oxide.

[0058] In some embodiments, the epoxy compound is a C10-C20 alkyl ethylene oxide.

[0059] In some embodiments, the epoxy compound is at least one of 1,2-epoxydecane, 1,2-epoxydodecane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane, 1,2-epoxyoctadecane, and 1,2-epoxyeicosane.

[0060] S3. Mix the precursor with 10-150 parts of solid waste powder, and physically grind for 0.5-2h to obtain a stabilizer.

[0061] The addition of solid waste powder, on the one hand, can fill the internal pores of the soil and bond with the carboxyl groups on the modified graphene oxide to form an internal network structure with a higher degree of cross-linking, thereby optimizing the internal structure of the soil; on the second hand, the viscosity generated by the solid waste powder after absorbing water helps to increase the degree of aggregation between the soil, thereby improving the soil density; on the third hand, the solid waste powder can fix the heavy metal ions in the soil through ion exchange, chemical coordination and other methods to improve soil stability.

[0062] In some embodiments, the raw materials for preparing the stabilizer include, by weight: 9-45 parts of graphene oxide, 2-16 parts of melamine, 0.2-1.5 parts of epoxy compound, and 20-120 parts of solid waste powder.

[0063] In some embodiments, the solid waste powder is at least one of expanded soil, steel slag, calcite, fly ash, magnesium slag, and lime.

[0064] In some embodiments, the solid waste powder is a mixture of expanded soil, steel slag and calcite;

[0065] In some embodiments, the mass ratio of expansive soil, steel slag and calcite is 1:(0.1-1.3):(0.1-1.0).

[0066] In some embodiments, the mass ratio of expansive soil, steel slag and calcite is 1:(0.5-1.0):(0.2-0.5).

[0067] The specific proportion of solid waste powder can well balance the relationship between soil expansion and contraction and strength improvement, synergistically modify graphene oxide and epoxy compounds, and jointly improve soil bearing capacity and stability.

[0068] In some embodiments, the average particle size of the expanded soil is 200-400 microns.

[0069] In some embodiments, the average particle size of the expanded soil is 250-350 microns.

[0070] In some embodiments, the average particle size of the slag is 160-270 microns.

[0071] In some embodiments, the average particle size of the slag is 180-230 microns.

[0072] In some embodiments, the calcite has an average particle size of 180-300 microns.

[0073] In some embodiments, the calcite has an average particle size of 200-260 microns.

[0074] In some embodiments, the prepared soil stabilizer is applied to the stabilization treatment of contaminated soil in a contaminated plant.

[0075] In some embodiments, the stabilizer accounts for 1-10% by mass of the contaminated soil.

[0076] In some embodiments, the stabilizer accounts for 3-8% by mass of the contaminated soil.

[0077] In some embodiments, the soil stabilizer prepared in the present application can be sprayed in proportion on the contaminated soil in the pollution plant to be treated, and fully stirred using in-situ solidification equipment to complete the stabilization treatment of the contaminated soil.

[0078] In some embodiments, the contaminated soil in the contaminated plant can be taken out, mixed evenly with a soil stabilizer, and then the mixture can be backfilled.

[0079] In some embodiments, the contaminated area may be subjected to some barrier and anti-seepage treatments, or uncontaminated soil (such as planting soil) may be laid on the surface of the soil after stabilization treatment for other subsequent applications (such as planting green plants).

[0080] Example

[0081] The following examples describe the disclosure of the present invention in more detail, and these examples are intended for illustrative purposes only, as various modifications and variations within the scope of the disclosure of the present invention will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0082] Example 1

[0083] A chemical for soil solidification treatment in a polluted plant, comprising the following components: 24 parts of graphene oxide, 7.7 parts of melamine, 0.6 parts of 1,2-epoxyhexadecane, and 66 parts of solid waste powder (30 parts of expansive soil (average particle size 300 microns), 24 parts of steel slag (average particle size 200 microns), and 12 parts of calcite (average particle size 230 microns)).

[0084] Among them, the mass ratio of graphene oxide to melamine is: 24:7.7=1:0.32; the weight ratio of expansive soil, steel slag and calcite in the solid waste powder is: 30:24:12=1:0.8:0.4.

[0085] A method for preparing a medicament for soil solidification treatment in a polluted plant comprises the following steps:

[0086] S1. Dissolve 7.7 parts of melamine in 200 parts of hot water at 80° C. to obtain a melamine aqueous solution; then disperse 24 parts of graphene oxide in 200 parts of water, stir thoroughly for 2 hours, heat to 80° C., add the melamine aqueous solution, stir for 2 hours, filter, wash, and dry to obtain modified graphene oxide.

[0087] S2. Add the modified graphene oxide prepared in step S1 and 0.6 parts of 1,2-epoxyhexadecane to 400 parts of ethanol in sequence, stir at 80° C. for 4 hours, filter, wash and dry to obtain a precursor.

[0088] S3. Mix the precursor with the solid waste powder and ball mill for 1.5 hours to obtain a stabilizer.

[0089] Example 2

[0090] A chemical for soil solidification treatment in a polluted plant, comprising the following components: 9 parts of graphene oxide, 2 parts of melamine, 0.2 parts of 1,2-epoxydodecane, 23 parts of solid waste powder (13 parts of expansive soil (average particle size 250 microns), 7 parts of steel slag (average particle size 180 microns), 3 parts of calcite (average particle size 200 microns)).

[0091] Among them, the mass ratio of graphene oxide to melamine is: 9:2=1:0.22; the weight ratio of expansive soil, steel slag and calcite in the solid waste powder is: 13:7:3=1:0.54:0.23.

[0092] A method for preparing a medicament for soil solidification treatment in a polluted plant comprises the following steps:

[0093] S1. Dissolve 2 parts of melamine in 120 parts of hot water at 75°C to obtain a melamine aqueous solution; then disperse 9 parts of graphene oxide in 100 parts of water, stir thoroughly for 0.5h, heat to 75°C, add the melamine aqueous solution, stir for 3h, filter, wash and dry to obtain modified graphene oxide.

[0094] S2. Add the modified graphene oxide prepared in step S1 and 0.2 parts of 1,2-epoxydodecane to 300 parts of ethanol in sequence, stir at 60° C. for 6 hours, filter, wash and dry to obtain a precursor.

[0095] S3. Mix the precursor with the solid waste powder and ball mill for 0.5 h to obtain a stabilizer.

[0096] Example 3

[0097] A chemical for soil solidification treatment in a polluted plant, comprising the following components: 42 parts of graphene oxide, 16 parts of melamine, 1.1 parts of 1,2-epoxytetradecane, 120 parts of solid waste powder (48 parts of expansive soil (average particle size 350 microns) , 48 parts of steel slag (average particle size 230 microns) , 24 parts of calcite (average particle size 260 microns)).

[0098] Among them, the mass ratio of graphene oxide to melamine is: 42:16=1:0.38; the weight ratio of expansive soil, steel slag and calcite in the solid waste powder is: 48:48:24=1:1:0.5.

[0099] A method for preparing a medicament for soil solidification treatment in a polluted plant comprises the following steps:

[0100] S1. Dissolve 16 parts of melamine in 300 parts of 95°C hot water to obtain a melamine aqueous solution; then disperse 42 parts of graphene oxide in 300 parts of water, stir thoroughly for 1 hour, heat to 95°C, add the melamine aqueous solution, stir for 1 hour, filter, wash and dry to obtain modified graphene oxide.

[0101] S2. Add the modified graphene oxide prepared in step S1 and 1.1 parts of 1,2-epoxytetradecane to 500 parts of ethanol in sequence, stir at 90° C. for 2 hours, filter, wash and dry to obtain a precursor.

[0102] S3. Mix the precursor with the solid waste powder and ball mill for 2 h to obtain a stabilizer.

[0103] Example 4

[0104] The steps for preparing the stabilizer in Example 4 and Example 1 are basically the same, the main difference being that the amounts of melamine and graphene oxide added in step S1 are different, 11.7 parts of melamine, 20 parts of graphene oxide, and the mass ratio of graphene oxide to melamine is 1:0.59.

[0105] Example 5

[0106] The steps for preparing the stabilizer in Example 5 and Example 1 are basically the same, the main difference being that the amounts of melamine and graphene oxide added in step S1 are different, 3 parts of melamine, 28.7 parts of graphene oxide, and the mass ratio of graphene oxide to melamine is 1:0.10.

[0107] Example 6

[0108] The steps for preparing the stabilizer in Example 6 and Example 1 are basically the same, the main difference being that in step S2, the epoxy compound added is 1,2-octyl oxide.

[0109] Comparative Example 1

[0110] The steps for preparing the stabilizer in Comparative Example 1 and Example 1 are basically the same, the main difference being that 2-(aminomethyl)-2-methyl-1,3-propylenediamine is used instead of melamine in step S1.

[0111] Comparative Example 2

[0112] The steps for preparing the stabilizer in Comparative Example 2 and Example 1 are basically the same, the main difference being that the specific amounts and components of the solid waste powder added in step S3 are different. The specific composition of the solid waste powder is 39 parts of steel slag and 27 parts of calcite, and no expansive soil is added.

[0113] Comparative Example 3

[0114] The steps for preparing the stabilizer in Comparative Example 3 and Example 1 are basically the same, the main difference being that the specific amounts and components of the solid waste powder added in step S3 are different. The specific composition of the solid waste powder is 42 parts of expansive soil and 24 parts of calcite, and no steel slag is added.

[0115] Comparative Example 4

[0116] The steps for preparing the stabilizer in Comparative Example 4 and Example 1 are basically the same, the main difference being that the specific amounts and components of the solid waste powder added in step S3 are different. The specific composition of the solid waste powder is 36 parts of expansive soil and 30 parts of steel slag, and no calcite is added.

[0117] Comparative Example 5

[0118] The steps for preparing the stabilizer in Comparative Example 5 and Example 1 are basically the same, the main difference being that graphene oxide is not added. The specific steps include:

[0119] S1. Add 5.7 parts of melamine and 0.6 parts of 1,2-epoxyhexadecane to 400 parts of ethanol in sequence, stir at 80° C. for 25 hours, filter, wash and dry to obtain a precursor.

[0120] S2. Mix the precursor with the solid waste powder and ball mill for 1.5 hours to obtain a stabilizer.

[0121] Experimental Example Performance Test Method

[0122] The contaminated soil in the polluted plant, the mixture of the homemade stabilizer and water in the embodiment and the comparative example, the stabilizer accounting for 5% of the soil mass, the soil moisture content is 16%, are made into cylindrical specimens of Φ150mm×H150mm, demolded, and after curing for 7 days, the unconfined compressive strength (bearing capacity) test and the heavy metal content in the soil are tested.

[0123] Unconfined compressive strength: The test is carried out in accordance with T0805-1994 "Test method for unconfined compressive strength of materials stabilized with inorganic binders".

[0124] Heavy metal content detection: The soil after curing is crushed and toxic leaching (heavy metal leaching test) is carried out according to HJ T299-2007 "Toxicity leaching method of solid waste leaching - sulfuric acid and nitric acid method".

[0125] Table 1: Performance test results

[0126]

[0127] From the data of Examples 1 to 3, it can be seen that the contaminated soil stabilization agent prepared in Examples 1 to 3 can well enhance the bearing capacity of the soil and reduce the heavy metal Zn in the soil. 2+ and Pb 2+ The content.

[0128] Compared with Example 1, the sample strength and heavy metal ion fixation effect of Example 4 are reduced. The reason may be that in Example 4, the melamine content used in the process of modifying graphene oxide is increased, the graphene oxide content is reduced, the overall hydrophilic effect is reduced, and the complexation effect on heavy metal ions is reduced, so the various properties of the soil are reduced.

[0129] Compared with Example 1, the strength of the sample in Example 5 decreases. This may be due to the decrease in the content of melamine used in the process of modifying graphene oxide, while the content of graphene oxide increases, which reduces the epoxy compounds that can be grafted with melamine, resulting in a decrease in the long carbon chain in the stabilizer, which is not conducive to hydrophobic modification and affects the cohesion of soil particles, thereby causing a decrease in strength.

[0130] Compared with Example 1, Example 6 uses 1,2-epoxyoctane instead of 1,2-epoxyhexadecane in Example 1, and the strength of the sample is significantly reduced. The reason may be that the alkyl chain grafted on the modified graphene oxide is relatively short, the hydrophobicity of the precursor deteriorates, and the hydrophobic modification effect on the soil particles is not good. Therefore, the cohesion between the soil particles is reduced, and the density inside the soil is relatively poor, so the strength of the sample is reduced.

[0131] Therefore, it can be seen from the experimental data of Examples 1 and 6 that: the epoxy compound is introduced into the formula and grafted on the modified graphene oxide. The modified graphene oxide acts as the hydrophilic end and is adsorbed on the surface of the soil particles to destroy the water film. The long-chain alkyl group of the epoxy compound acts as the hydrophobic end, which can improve the hydrophobicity of the soil particles, and synergizes with the bonding effect and water absorption effect of the solid waste powder to jointly improve the cohesion of the soil particles.

[0132] Compared with Example 1, the strength and metal ion fixation effect of the samples in Comparative Examples 2, 3, and 4 are all reduced, indicating that the compound solid waste powder added to the formula can not only fill the internal pores of the soil, but also connect with graphene oxide to jointly optimize the internal structure of the soil and improve the soil bearing capacity, and all three can play a certain role in fixing metal ions. The specific proportion of solid waste powder can balance the relationship between soil expansion and contraction and strength improvement, thereby improving soil stability.

[0133] Compared with Example 1, Comparative Example 1 uses 2-(aminomethyl)-2-methyl-1,3-propylenediamine instead of melamine. On the one hand, there is no triazine ring in the structure of 2-(aminomethyl)-2-methyl-1,3-propylenediamine, and the steric hindrance is small, which may cause the dispersion of modified graphene oxide in the soil to decrease, and the stress on the outside cannot be diffused in time, resulting in stress concentration in the soil and cracks, so the soil bearing capacity is deteriorated; on the other hand, the absence of the triazine ring may lead to a decrease in the degree of graphene oxide exfoliation, and a decrease in the exposed active groups such as hydroxyl and carboxyl groups, which affects the synergistic adsorption of heavy metal ions in the soil by the stabilizer, and its adsorption effect on metal ions is poor, so the metal fixation effect of the soil is deteriorated.

[0134] Compared with Example 1, in Comparative Example 5, graphene oxide is not added, and various properties of the soil are significantly reduced. The reasons may be that: the lack of graphene oxide cannot be grafted with epoxy compounds to generate precursors with hydrophilic and hydrophobic ends, the hydrophilicity and water absorption of the stabilizer are deteriorated, and it can neither be adsorbed on the surface of soil particles to destroy the water film nor absorb excess water in the soil. The cohesion between soil particles is significantly reduced, the internal structure of the soil is deteriorated, the density is reduced, and the soil bearing capacity is reduced; at the same time, the lack of graphene also loses its own benefits on the mechanical properties of the soil, so the bearing capacity is significantly reduced; in addition, the lack of graphene oxide also leads to a significant reduction in active groups such as hydroxyl and carboxyl groups in the stabilizer, and the curing effect on heavy metal ions in the system is significantly reduced. Combined with the significant decrease in the density of the soil system, the heavy metal ion fixation effect of the soil is also significantly reduced.

[0135] Therefore, it can be seen from the experimental data of Example 1 and Comparative Examples 1 and 5 that the intervention of graphene oxide itself in the stabilizer can effectively improve the mechanical properties of the soil; melamine with a triazine ring is grafted on the surface of graphene oxide to obtain modified graphene oxide, and the larger steric hindrance is conducive to the uniform dispersion of modified graphene oxide in the soil, avoiding the generation of cracks caused by stress concentration, and improving the soil bearing capacity. At the same time, the high degree of exfoliation brought by melamine to graphene oxide exposes a large number of active groups such as hydroxyl and carboxyl groups to play a role in fixing heavy metal ions. In addition, the hydrophilic water absorption of modified graphene oxide, together with epoxy compounds, constructs a precursor with a hydrophilic end and a hydrophobic end, optimizes the aggregation of soil particles, improves soil density, and further improves soil bearing capacity and metal ion fixation effect.

[0136] Therefore, the stabilizer prepared by the present invention using graphene oxide, melamine, epoxy compounds, and solid waste powder as raw materials contains a large number of active groups such as carboxyl and hydroxyl groups, has a strong adsorption effect on heavy metal ions, can effectively regulate the internal structure of the soil, and solidify heavy metal ions, thereby improving the bearing capacity and stability of the soil.

[0137] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A chemical for solidifying soil in polluted plants, characterized in that: The raw materials include, by weight: 5-55 parts of graphene oxide, 1-20 parts of melamine, 0.1-3 parts of epoxy compound, and 10-150 parts of solid waste powder; The epoxy compound is at least one of 1,2-epoxydecane, 1,2-epoxydodecane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane, 1,2-epoxyoctadecane and 1,2-epoxyeicosane; The solid waste powder is a mixture of expansive soil, steel slag and calcite; The mass ratio of the expansive soil, steel slag and calcite is 1: (0.1-1.3): (0.1-1.0), The soil solidification treatment agent for the polluted plant is prepared according to the following method: S1, dissolving melamine in water to obtain a melamine aqueous solution; dispersing graphene oxide in water, fully stirring, heating, adding the melamine aqueous solution, stirring, filtering, washing, and drying to obtain modified graphene oxide; S2, adding the modified graphene oxide and the epoxy compound into ethanol, stirring, filtering, washing, and drying to obtain a precursor; S3. Mix the precursor with the solid waste powder, grind them physically, and obtain a soil solidification agent for the polluted plant.

2. The agent for solidifying soil in polluted plants according to claim 1, characterized in that: The mass ratio of the graphene oxide to melamine is 1:0.1-0.

6.

3. The agent for solidifying soil in polluted plants according to claim 1, characterized in that: The mass ratio of the graphene oxide to melamine is 1:0.2-0.

4.

4. The agent for solidifying soil in polluted plants according to claim 1, characterized in that: The mass ratio of the expansive soil, steel slag and calcite is 1: (0.5-1.0): (0.2-0.5).

5. The agent for solidifying soil in polluted plants according to claim 1, characterized in that: The average particle size of the calcite is 180-300 microns, the average particle size of the steel slag is 160-270 microns, and the average particle size of the expansive soil is 200-400 microns.

6. The agent for solidifying soil in polluted plants according to claim 1, characterized in that: The average particle size of the calcite is 200-260 microns, the average particle size of the steel slag is 180-230 microns, and the average particle size of the expansive soil is 250-350 microns.

7. Use of the agent for solidifying soil in a polluted plant according to any one of claims 1 to 6, characterized in that: Used for stabilization of contaminated soil in polluted plants.

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