Remediation material for degrading chlorinated hydrocarbon in polluted soil and preparation method thereof

Abstract

The invention belongs to the technical field of soil remediation, and particularly relates to a remediation material for degrading polluted soil chlorinated hydrocarbon and a preparation method of the remediation material. The repair material for degrading the chlorinated hydrocarbon in the polluted soil is prepared from the following raw materials: humic acid, rhamnolipid, a biological agent and diatomite. The final repairing material utilizes mutual complementation and mutual synergism of humic acid, rhamnolipid, the biological agent and diatomite, has a remarkable effect in the aspect of degrading trichloroethylene, cis-1, 2-dichloroethylene, trichloroethane and 1, 2-dichloroethane, can be used for repairing chlorohydrocarbon polluted soil, and achieves a better degradation effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil remediation, and particularly relates to a remediation material for degrading chlorohydrocarbons in contaminated soil and a preparation method thereof. Background Art

[0002] Most chlorohydrocarbons are xenobiotics, which are widely used as chemical raw materials and organic solvents. Some chlorohydrocarbons accumulate in groundwater or soil and enter the food chain through bioaccumulation. They have stable chemical properties, poor biodegradability, and have carcinogenic, teratogenic, and mutagenic effects and genetic toxicity, posing a persistent pollution to the environment and seriously threatening human health.

[0003] The improper use of chlorinated olefins such as trichloroethylene (TCE) and chlorinated alkanes such as trichloroethane (TCA) has caused serious pollution to the human environment. Ordinary soil remediation agents have low degradation efficiency for chlorohydrocarbon pollution.

[0004] Chinese Patent CN118305177A discloses a biological combined remediation method for chlorohydrocarbon-contaminated soil, which includes the following steps: enriching and screening an anaerobic microbial complex from the chlorohydrocarbon-contaminated soil to be remediated, transplanting cattail seedlings in the chlorohydrocarbon-contaminated soil, and inoculating the microbial complex. When the cattail grows to the flowering or mature stage, the cattail is harvested and removed from the contaminated soil. This method uses biological combination with microorganisms for remediation, and the remediation cycle is long.

[0005] Chinese Patent CN105860989A discloses a soil remediation agent and its application in the remediation of chlorohydrocarbon-contaminated soil. The raw material composition includes: metal powder: 150-200 parts by weight; aerobic degradation bacteria: 100-500 parts by weight; humic acid: 100-600 parts by weight. The soil remediation agent has a certain degradation effect on dichloroethane, trichloroethane, and dichloroethylene. However, since this soil remediation agent uses metal powder, the tiny particle size of the metal powder makes it easy to penetrate into the soil pores, which may lead to a decrease in soil aeration and a change in water infiltration ability. At the same time, the chemical reaction of the metal powder may cause fluctuations in the soil pH value, further affecting the soil aggregate structure and stability, thus having a long-term impact on the properties of the cultivated layer soil.

[0006] Developing a remediation material for efficiently degrading chlorohydrocarbons in contaminated soil is of great significance for the remediation of soil chlorohydrocarbon pollution. Summary of the Invention

[0007] The purpose of the present invention is to provide a remediation material for degrading chlorinated hydrocarbons in contaminated soil, its preparation method and application. The remediation material of the present invention utilizes humic acid, rhamnolipid, biological bacteria agent and diatomite to complement and cooperate with each other, and has remarkable effects in degrading vinyl chloride, cis-1,2-dichloroethylene, trichloroethane and 1,2-dichloroethane, and can be used to remediate chlorinated hydrocarbon contaminated soil.

[0008] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0009] The first object of the present invention is to provide a remediation material for degrading chlorinated hydrocarbons in contaminated soil.

[0010] The second object of the present invention is to provide a preparation method of the above-mentioned remediation material for degrading chlorinated hydrocarbons in contaminated soil.

[0011] The third object of the present invention is to provide the use of the above-mentioned remediation material for degrading chlorinated hydrocarbons in contaminated soil.

[0012] To achieve the first object, the technical solution adopted by the present invention is:

[0013] The present invention provides a remediation material for degrading chlorinated hydrocarbons in contaminated soil, and the remediation material is made of humic acid, rhamnolipid, biological bacteria agent and diatomite.

[0014] In some embodiments, the remediation material for degrading chlorinated hydrocarbons in contaminated soil is made of the following raw materials by weight: 10-20 parts of humic acid, 6-10 parts of rhamnolipid, 15-25 parts of biological bacteria agent and 10-20 parts of diatomite, wherein the biological bacteria agent is composed of Bacillus subtilis, Sinorhizobium and methanotrophic bacteria.

[0015] In some embodiments, the remediation material for degrading chlorinated hydrocarbons in contaminated soil is made of the following raw materials by weight: 15 parts of humic acid, 8 parts of rhamnolipid, 20 parts of biological bacteria agent and 15 parts of diatomite.

[0016] In some embodiments, the biological bacteria agent is Bacillus subtilis, Sinorhizobium and methanotrophic bacteria with a mass ratio of 1:2-4:3-5.

[0017] In some preferred embodiments, the biological bacteria agent is Bacillus subtilis, Sinorhizobium and methanotrophic bacteria with a mass ratio of 1:3:4.

[0018] To achieve the second object, the technical solution adopted by the present invention is:

[0019] The preparation method of the remediation material for degrading chlorohydrocarbons in contaminated soil of the present invention is as follows: Mix Bacillus subtilis, Rhizobium sinense and methanotrophic bacteria evenly according to the described mass ratio to obtain a biological bacterial agent; Weigh humic acid, rhamnolipid and diatomite by weight parts, mix them to obtain a mixture one; Mix the biological bacterial agent and the mixture one to obtain the remediation material for degrading chlorohydrocarbons in contaminated soil.

[0020] To achieve the third object, the technical solution adopted by the present invention is:

[0021] The present invention provides the use of the remediation material for degrading chlorohydrocarbons in contaminated soil in the preparation of the remediation material for degrading chlorohydrocarbons in contaminated soil.

[0022] The present invention provides a soil remediation method, which includes: using the remediation material for degrading chlorohydrocarbons in contaminated soil according to any one of claims 1-4 to remediate the contaminated soil.

[0023] In some embodiments, the contaminated soil is chlorohydrocarbon-contaminated soil.

[0024] In some preferred embodiments, the chlorohydrocarbon is at least one of trichloroethylene, cis-1,2-dichloroethylene, trichloroethane, 1,2-dichloroethane.

[0025] Humic acid is a type of macromolecular organic matter that cannot enter the cell, but can be used as an electron acceptor or electron shuttle for extracellular respiration of microorganisms, and can transfer the electrons generated by microbial metabolism to chlorohydrocarbons to promote their reduction and degradation.

[0026] Biodegradation of chlorohydrocarbons is still one of the effective methods for ecological remediation at present. The structure and function of the microbial community in different chlorohydrocarbon-contaminated sites are closely related to environmental factors, and the addition of appropriate exogenous microbial agents can promote the degradation of chlorohydrocarbons.

[0027] The present invention uses components such as humic acid, rhamnolipid, biological bacterial agent and diatomite in combination with each other, and utilizes the synergistic effect between the raw material components to provide an efficient remediation material for degrading chlorohydrocarbons in contaminated soil.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The remediation material of the present invention uses humic acid, rhamnolipid, biological bacterial agent and diatomite to complement and cooperate with each other, and has remarkable effects in degrading trichloroethylene, cis-1,2-dichloroethylene, trichloroethane, 1,2-dichloroethane, and can be used to remediate chlorohydrocarbon-contaminated soil.

[0030] The remediation material of the present invention can be used for the remediation of chlorohydrocarbon-contaminated soil, and is expected to make new breakthroughs in the field of remediation of chlorohydrocarbon-contaminated soil. Description of the Drawings

[0031] Figure 1 Removal rates of trichloroethylene under different treatments. Different lowercase letters above the bar graphs indicate significant differences between different groups (P < 0.05).

[0032] Figure 2 Removal rates of cis-1,2-dichloroethylene under different treatments. Different lowercase letters above the bar graphs indicate significant differences between different groups (P < 0.05).

[0033] Figure 3 Removal rates of trichloroethane under different treatments. Different lowercase letters above the bar graphs indicate significant differences between different groups (P < 0.05).

[0034] Figure 4 Removal rates of 1,2-dichloroethane under different treatments. Different lowercase letters above the bar graphs indicate significant differences between different groups (P < 0.05). Detailed implementation manners

[0035] The following will describe the implementation schemes of the present invention in detail in combination with embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0036] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not used to limit the present invention.

[0037] Example 1

[0038] A remediation material for degrading chlorinated hydrocarbons in contaminated soil is prepared from the following components by weight: 15 parts of humic acid, 8 parts of rhamnolipid, 20 parts of biological bactericide, and 15 parts of diatomite.

[0039] The biological bactericide is a mixture of Bacillus subtilis, Sinorhizobium meliloti, and methanotrophic bacteria in a mass ratio of 1:3:4.

[0040] Mix Bacillus subtilis, Sinorhizobium meliloti, and methanotrophic bacteria evenly according to the said mass ratio to obtain the biological bactericide; weigh humic acid, rhamnolipid, and diatomite by weight, mix them to obtain mixture one; mix the biological bactericide and mixture one to obtain the remediation material for degrading chlorinated hydrocarbons in contaminated soil.

[0041] Example 2

[0042] A remediation material for degrading chlorinated hydrocarbons in contaminated soil is prepared from the following components by weight: 20 parts of humic acid, 6 parts of rhamnolipid, 25 parts of biological bactericide, and 10 parts of diatomite.

[0043] The biological bactericide is Bacillus subtilis, Rhizobium sinicum, and methanotrophic bacteria with a mass ratio of 1:2:5.

[0044] The preparation method refers to Example 1.

[0045] Example 3

[0046] A remediation material for degrading chlorohydrocarbons in contaminated soil is made of the following components by weight: 10 parts of humic acid, 10 parts of rhamnolipid, 15 parts of biological bactericide, and 20 parts of diatomite.

[0047] The biological bactericide is Bacillus subtilis, Rhizobium sinicum, and methanotrophic bacteria with a mass ratio of 1:4:3.

[0048] The preparation method refers to Example 1.

[0049] Example 4

[0050] A remediation material for degrading chlorohydrocarbons in contaminated soil is made of the following components by weight: 15 parts of humic acid, 10 parts of rhamnolipid, 15 parts of biological bactericide, and 15 parts of diatomite.

[0051] The biological bactericide is Bacillus subtilis, Rhizobium sinicum, and methanotrophic bacteria with a mass ratio of 1:2:3.

[0052] The preparation method refers to Example 1.

[0053] Example 5

[0054] A remediation material for degrading chlorohydrocarbons in contaminated soil is made of the following components by weight: 10 parts of humic acid, 10 parts of rhamnolipid, 20 parts of biological bactericide, and 20 parts of diatomite.

[0055] The biological bactericide is Bacillus subtilis, Rhizobium sinicum, and methanotrophic bacteria with a mass ratio of 1:4:5.

[0056] The preparation method refers to Example 1.

[0057] Example 6

[0058] A remediation material for degrading chlorohydrocarbons in contaminated soil is made of the following components by weight: 20 parts of humic acid, 8 parts of rhamnolipid, 25 parts of biological bactericide, and 10 parts of diatomite.

[0059] The biological bactericide is Bacillus subtilis, Rhizobium sinicum, and methanotrophic bacteria with a mass ratio of 1:4:5.

[0060] The preparation method refers to Example 1.

[0061] Comparative Example 1

[0062] 13 parts of rhamnolipid, 25 parts of biological bacteria agent and 20 parts of diatomite.

[0063] Compared with Example 1, the difference lies in that it does not contain humic acid, and the dosages of rhamnolipid, biological bacteria agent and diatomite are different.

[0064] The preparation method refers to Example 1.

[0065] Comparative Example 2

[0066] 18 parts of humic acid, 22 parts of biological bacteria agent and 18 parts of diatomite.

[0067] Compared with Example 1, the difference lies in that it does not contain rhamnolipid, and the dosages of humic acid, biological bacteria agent and diatomite are different.

[0068] The preparation method refers to Example 1.

[0069] Comparative Example 3

[0070] 20 parts of humic acid, 18 parts of rhamnolipid and 20 parts of diatomite.

[0071] Compared with Example 1, the difference lies in that it does not contain biological bacteria agent, and the dosages of humic acid, rhamnolipid and diatomite are different.

[0072] The preparation method refers to Example 1.

[0073] Comparative Example 4

[0074] 20 parts of humic acid, 13 parts of rhamnolipid and 25 parts of biological bacteria agent.

[0075] Compared with Example 1, the difference lies in that it does not contain diatomite, and the dosages of humic acid, rhamnolipid and biological bacteria agent are different.

[0076] The preparation method refers to Example 1.

[0077] Comparative Example 5

[0078] 15 parts of humic acid, 8 parts of rhamnolipid, 20 parts of biological bacteria agent and 15 parts of diatomite.

[0079] Compared with Example 1, the difference lies in that the biological bacteria agent is different. The biological bacteria agent is Bacillus subtilis and methanotrophic bacteria with a mass ratio of 2:5.

[0080] The preparation method refers to Example 1.

[0081] Test Example 1

[0082] A chlorinated hydrocarbon mother liquor was prepared with a mass concentration of 1011.9 mg / L. The ratio of 1,2-dichloroethane (1,2-DCA), trichloroethane (TCA), cis-1,2-dichloroethylene (cis-1,2-DCE), and trichloroethylene (TCE) was 1:1:1:1. The mass concentrations of 1,2-DCA, TCA, cis-1,2-DCE, and TCE in the mother liquor were 0.31, 0.30, 0.32, and 0.37 g / L, respectively.

[0083] 70g of clay soil sample was added to each 100mL brown bottle and sealed with a gland. 280μL of chlorinated hydrocarbon mother liquor and a small amount of ultrapure water were then added to mix the soil and contaminants evenly. 5g of the remediation material of the relevant embodiments of the present invention was then added to each bottle to mix the remediation material, soil, and contaminants evenly. The treated remediation materials were Group A (Example 1), Group B (Example 2), Group C (Example 3), Group D (Comparative Example 1), Group E (Comparative Example 2), Group F (Comparative Example 3), Group G (Comparative Example 4), and Group H (Comparative Example 5). No remediation material was added to the control group (CK group).

[0084] Three replicates were set for each treatment, and the reaction bottles were kept at 35°C for 9 days and then sampled for testing.

[0085] The degradation effect of chlorinated hydrocarbons was investigated based on the final mass concentration of chlorinated hydrocarbons desorbed from each reaction bottle. The volatile chlorinated hydrocarbons were determined by purge and trap gas chromatography.

[0086] Experimental results

[0087] As shown in Table 1, Figure 1 As shown, the TCE removal rates of group A, group B, and group C were 81.5%, 76.3%, and 79.1%, respectively, which were better than those of group D, group E, group F, group G, group H, and group I.

[0088] Table 1 Removal rate of TCE by each treatment

[0089]

[0090] Different lowercase letters indicate significant differences among different groups (P<0.05).

[0091] As shown in Table 2, Figure 2 As shown, the removal rates of cis-1,2-DCE in groups A, B and C were 95.4%, 91.7% and 94.6%, respectively, which were better than those in groups D, E, F, G, H and I.

[0092] Table 2 Removal rate of cis-1,2-DCE by each treatment

[0093]

[0094] Different lowercase letters indicate significant differences between different groups (P < 0.05).

[0095] As Figure 3 shown, the removal rates of TCA by Group A, Group B, and Group C were 51.2%, 48.7%, and 46.1% respectively, which were superior to those of Group D, Group E, Group F, Group G, Group H, and Group I.

[0096] As Figure 4 shown, the removal rates of 1,2-DCA by Group A, Group B, and Group C were 41.9%, 39.0%, and 37.8% respectively, which were superior to those of Group D, Group E, Group F, Group G, Group H, and Group I.

[0097] The remediation material of the present invention utilizes humic acid, rhamnolipid, biological bactericide, and diatomite to complement and synergize with each other, and has remarkable effects in degrading 1,2-DCA, TCA, cis-1,2-DCE, and TCE, and can be used for remediating chlorinated hydrocarbon-contaminated soil.

[0098] Comparative Example 1 did not contain humic acid, and the dosages of rhamnolipid, biological bactericide, and diatomite were changed; Comparative Example 2 did not contain rhamnolipid, and the dosages of humic acid, biological bactericide, and diatomite were changed; Comparative Example 3 did not contain biological bactericide, and the dosages of humic acid, rhamnolipid, and diatomite were changed; Comparative Example 4 did not contain diatomite, and the dosages of humic acid, rhamnolipid, and biological bactericide were changed; Comparative Example 5 changed the composition of the biological bactericide, and the effect of degrading chlorinated hydrocarbon pollution was significantly reduced.

[0099] Based on the synergistic effect of each component, the present invention can achieve efficient degradation and removal of chlorinated hydrocarbons in soil, improve the removal ability of soil to chlorinated hydrocarbons, and the soil remediator has good stability and low cost.

[0100] In the above text, the present invention has been described in detail with general descriptions and specific examples. However, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A remediation material for degrading chlorinated hydrocarbons in contaminated soil, characterized in that The remediation material for degrading chlorohydrocarbons in contaminated soil is prepared from the following raw materials by weight: 10-20 parts of humic acid, 6-10 parts of rhamnolipid, 15-25 parts of biological bacteria agent, and 10-20 parts of diatomite, wherein the biological bacteria agent is composed of Bacillus subtilis, Sinorhizobium and methanotrophs.

2. The remediation material for degrading chlorohydrocarbons in contaminated soil according to claim 1, characterized in that, The remediation material for degrading chlorohydrocarbons in contaminated soil is prepared from the following raw materials by weight: 15 parts of humic acid, 8 parts of rhamnolipid, 20 parts of biological bacteria agent, and 15 parts of diatomite.

3. The remediation material for degrading chlorohydrocarbons in contaminated soil according to claim 1, wherein, The remediation material for degrading chlorohydrocarbons in contaminated soil is prepared from the following raw materials by weight: 20 parts of humic acid, 6 parts of rhamnolipid, 25 parts of biological bacteria agent, and 10 parts of diatomite.

4. The remediation material for degrading chlorohydrocarbons in contaminated soil according to claim 1, characterized in that, The remediation material for degrading chlorohydrocarbons in contaminated soil is prepared from the following raw materials by weight: 10 parts of humic acid, 10 parts of rhamnolipid, 15 parts of biological bacteria agent, and 20 parts of diatomite.

5. The remediation material for degrading chlorinated hydrocarbons in contaminated soil according to any one of claims 1-4, characterized in that, The biological bacteria agent is Bacillus subtilis, Sinorhizobium and methanotrophs with a mass ratio of 1:2-4:3-5.

6. The remediation material for degrading chlorinated hydrocarbons in contaminated soil according to claim 5, characterized in that, The biological bacteria agent is Bacillus subtilis, Sinorhizobium and methanotrophs with a mass ratio of 1:3:

4.

7. The remediation material for degrading chlorinated hydrocarbons in contaminated soil according to any one of claims 1-4, characterized in that, The preparation method of the remediation material for degrading chlorohydrocarbons in contaminated soil is as follows: mix Bacillus subtilis, Sinorhizobium and methanotrophs evenly according to the said mass ratio to obtain the biological bacteria agent; weigh humic acid, rhamnolipid and diatomite by weight, mix them to obtain mixture one; mix the biological bacteria agent and mixture one to obtain the remediation material for degrading chlorohydrocarbons in contaminated soil.

8. A soil remediation method, characterized in that, The method includes: using the remediation material for degrading chlorohydrocarbons in contaminated soil according to any one of claims 1-4 to remediate the contaminated soil.

9. According to the repair method described in claim 8, wherein, The contaminated soil is chlorohydrocarbon-contaminated soil.

10. The repair method according to claim 9, wherein, The chlorohydrocarbon is at least one of trichloroethylene, cis-1,2-dichloroethylene, trichloroethane, 1,2-dichloroethane.

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