Soil conditioner for soil polluted by organic matters

Abstract

The invention belongs to the technical field of soil amendments, and relates to a soil amendment for organic matter contaminated soil. The soil conditioner comprises the following components: nitrogen-doped biochar, a complex microbial inoculant, a complex enzyme, hydroxypropyl methyl cellulose and a mineral additive, and the nitrogen-doped biochar loaded with complex bacteria is obtained by uniformly oscillating and mixing the complex microbial inoculant and the nitrogen-doped biochar; oscillating and uniformly mixing the compound enzyme and the mineral additive to obtain the mineral additive loaded with the compound enzyme; and finally, uniformly mixing the nitrogen-doped biochar loaded with the compound bacteria, the mineral additive loaded with the compound enzyme and hydroxypropyl methyl cellulose to obtain the soil conditioner for the soil polluted by the organic matters, and through the characteristics of the nitrogen-doped biochar and the synergistic effect of the compound microorganisms and an enzyme system, the soil conditioner can be applied to the soil polluted by the organic matters. Effective treatment and ecological restoration of the organic contaminated soil are achieved, and green development of the soil pollution treatment technology is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of soil conditioners, and more particularly relates to a soil conditioner for soil contaminated by organic matter. Background Art

[0002] With the acceleration of industrialization and the intensification of agricultural production activities, soil organic pollution has become an environmental problem that needs to be urgently addressed worldwide. Improper disposal of pesticide residues, industrial waste and domestic pollutants has led to the infiltration of a large amount of organic compounds into the soil, seriously affecting the physical and chemical properties and biological activity of the soil, restricting crop growth, and even affecting human health through the food chain. Traditional soil remediation technologies, such as physical stripping and chemical leaching, are often costly and complex to operate, and may cause secondary damage to the soil microenvironment, affecting the restoration of ecological balance. Although bioremediation methods are environmentally friendly and highly sustainable, they face limitations in practical applications such as slow degradation rates and lack of specificity, especially when dealing with complex organic pollutants.

[0003] Therefore, it is particularly important to develop a new soil conditioner that can not only efficiently remove a variety of organic pollutants in the soil, but also improve the physical and chemical properties of the soil and promote the restoration of ecological balance. The ideal conditioner should have the characteristics of strong adsorption capacity, high biological activity, wide sources and environmental friendliness. At the same time, its preparation process should be simple and easy to meet the needs of large-scale application, which has become a problem that technicians in this field need to overcome urgently. Summary of the invention

[0004] The purpose of the present invention is to provide a soil conditioner for organically contaminated soil, which can achieve effective treatment and ecological restoration of organically contaminated soil through the characteristics of nitrogen-doped biochar and the synergistic effect of composite microorganisms and enzyme systems, promote the green development of soil pollution control technology, solve the problems existing in the above-mentioned prior art, and achieve safe and efficient degradation of organic pollutants in soil.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is to provide a soil conditioner for organic polluted soil, which comprises the following components by weight:

[0007] 20-50 parts of nitrogen-doped biochar, 1-2 parts of composite bacterial agent, 1-2 parts of composite enzyme, 2-5 parts of hydroxypropyl methylcellulose and 10-20 parts of mineral additives.

[0008] Furthermore, the preparation steps of the nitrogen-doped biochar are:

[0009] The biomass and the nitrogen source are uniformly mixed, and pyrolysis reaction is carried out under a nitrogen atmosphere to prepare nitrogen-doped biochar.

[0010] Preferably, the biomass includes crop straw, wood waste or fruit shells.

[0011] Preferably, the nitrogen source includes urea, ammonia or struvite.

[0012] Preferably, the mass ratio of the biomass to the nitrogen source is 4 to 20:1.

[0013] Preferably, the temperature of the pyrolysis reaction is 400-600° C., the heating rate is 5-15° C. / min, and the time is 0.5-2 h.

[0014] Nitrogen-doped biochar can not only adsorb and fix organic pollutants, but also provide additional nitrogen, promote the growth of soil microorganisms, and enhance the soil's ability to retain water and fertilizer.

[0015] Furthermore, the composite bacterial agent includes nitrifying bacteria, denitrifying bacteria, Bacillus thuringiensis and acetic acid bacteria in equal mass ratios.

[0016] Preferably, the bacterial contents of the nitrifying bacteria, denitrifying bacteria, Bacillus thuringiensis and acetic acid bacteria are not less than 10 9 cfu / g.

[0017] Beneficial microorganisms in compound microbial agents can improve the structure of soil microbial communities, promote the growth of beneficial bacteria, inhibit the activity of pathogens, maintain soil ecological balance, and thus improve soil health. Hydroxypropyl methylcellulose (HPMC) as a binder enhances the dispersibility and stability of the modifier in the soil, helping to maintain the long-term effect of the modifier. At the same time, HPMC also provides a protective layer for microorganisms, improving their survival rate and activity.

[0018] Furthermore, the complex enzyme includes peroxidase, polyphenol oxidase, lyase, dehydrogenase and decarboxylase in a mass ratio of 1:1:0.1:0.1:0.1.

[0019] Preferably, the enzyme activities of the peroxidase, polyphenol oxidase, lyase, dehydrogenase and decarboxylase are not less than 5000 U / g.

[0020] Through the synergistic effect of compound bacteria and compound enzymes, a variety of organic pollutants can be effectively degraded, including industrial waste, pesticides and hormones. The nitrifying bacteria, denitrifying bacteria, Bacillus thuringiensis and acetic acid bacteria in the compound bacteria, as well as the peroxidase, polyphenol oxidase, lyase, dehydrogenase and decarboxylase in the compound enzyme work together to accelerate the biodegradation process of pollutants and improve the self-purification capacity of the soil.

[0021] Furthermore, the mineral additive includes bentonite or diatomaceous earth.

[0022] Mineral additives can increase the physical stability and adsorption capacity of the soil, while providing mineral nutrients, helping to improve soil structure and increase soil fertility.

[0023] The second technical solution of the present invention is to provide a method for preparing the soil conditioner for organic polluted soil, the steps comprising:

[0024] The composite bacterial agent and the nitrogen-doped biochar are shaken and mixed evenly to obtain nitrogen-doped biochar loaded with the composite bacteria;

[0025] The complex enzyme and the mineral additive are shaken and mixed evenly to obtain the mineral additive loaded with the complex enzyme;

[0026] The nitrogen-doped biochar loaded with composite bacteria, the mineral additive loaded with composite enzymes and hydroxypropyl methylcellulose are uniformly mixed to obtain the soil conditioner for organic matter-contaminated soil.

[0027] The present invention discloses the following technical effects:

[0028] The preparation method of the improver of the present invention is simple and easy to operate. The composite bacteria and the composite enzyme are respectively loaded on the nitrogen-doped biochar and the mineral additive. Through the double loading, the distribution uniformity and use efficiency of the composite enzyme in the soil can be improved. The composite enzyme quickly reduces the content of organic pollutants in the soil in the early stage of application, and then the organic pollutants are degraded by the adsorption of the nitrogen-doped biochar and the growth metabolism of the composite bacterial agent, so as to continuously reduce the content of organic pollutants in the soil and achieve the purpose of soil improvement.

[0029] The soil conditioner of the present invention mainly uses agricultural waste (such as crop straw, wood waste, fruit shells) and natural minerals as raw materials, realizes waste resource utilization, reduces environmental pollution, and conforms to the concept of sustainable development. DETAILED DESCRIPTION

[0030] 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.

[0031] It should be understood that the terms described in the present invention are only for describing a particular embodiment 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. The intermediate value in any stated value or stated range, and each smaller range between 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.

[0032] 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.

[0033] 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 those skilled in the art. The present invention description and examples are exemplary only.

[0034] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0035] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products.

[0036] The composite bacterial agent used in the specific embodiment of the present invention is nitrifying bacteria, denitrifying bacteria, Bacillus thuringiensis and acetic acid bacteria in equal mass ratio, and the bacterial content is not less than 10 9 cfu / g, all purchased from the market.

[0037] The composite enzyme used in the specific embodiment of the present invention is peroxidase, polyphenol oxidase, lyase, dehydrogenase and decarboxylase, with a mass ratio of 1:1:0.1:0.1:0.1, and the enzyme activity is not less than 5000 U / g, and all of them are purchased from the market.

[0038] The concentration of the ammonia water used in the specific embodiment of the present invention is 20 wt %.

[0039] The crop straw used in the specific implementation manner of the present invention is corn straw, and correspondingly, other crop straws can be replaced equally without affecting the realization of the technical effect.

[0040] The wood waste used in the specific embodiment of the present invention is sawdust, and correspondingly, other wood wastes can be replaced equally without affecting the realization of the technical effect.

[0041] The fruit shell used in the specific implementation manner of the present invention is coconut shell, and correspondingly, other fruit shells can be replaced equally without affecting the realization of the technical effect.

[0042] Example 1

[0043] The preparation steps of soil conditioner for organic polluted soil are as follows:

[0044] S1. The biomass (corn stalks) and the nitrogen source (urea) are uniformly mixed in a mass ratio of 10:1 to obtain a biochar precursor;

[0045] S2, heating the biochar precursor to 500°C at a heating rate of 10°C / min under a nitrogen atmosphere, keeping the temperature for 1 hour, and cooling the biochar precursor to room temperature under a nitrogen atmosphere to obtain nitrogen-doped biochar;

[0046] S3, oscillating and mixing 2 parts of the composite bacterial agent and 40 parts of the nitrogen-doped biochar to obtain nitrogen-doped biochar loaded with composite bacteria;

[0047] S4, oscillating and mixing 2 parts of the complex enzyme and 15 parts of the mineral additive (diatomaceous earth) to obtain a mineral additive loaded with the complex enzyme;

[0048] S5. Evenly mix the nitrogen-doped biochar loaded with composite bacteria, the mineral additive loaded with composite enzymes and 4 parts of hydroxypropyl methylcellulose to obtain a soil conditioner for organic-contaminated soil.

[0049] Example 2

[0050] The preparation steps of soil conditioner for organic polluted soil are as follows:

[0051] S1. Mix the biomass (wood chips) and the nitrogen source (ammonia water) in a mass ratio of 4:1 to obtain a biochar precursor;

[0052] S2, heating the biochar precursor to 400°C at a heating rate of 5°C / min under a nitrogen atmosphere, keeping the temperature for 2 hours, and cooling it to room temperature under a nitrogen atmosphere after the temperature is maintained to obtain nitrogen-doped biochar;

[0053] S3, oscillating and mixing 1 part of the composite bacterial agent and 30 parts of the nitrogen-doped biochar to obtain nitrogen-doped biochar loaded with composite bacteria;

[0054] S4, oscillating and mixing 1 part of the complex enzyme and 10 parts of the mineral additive (bentonite) to obtain a mineral additive loaded with the complex enzyme;

[0055] S5. Evenly mix the nitrogen-doped biochar loaded with composite bacteria, the mineral additive loaded with composite enzymes and 5 parts of hydroxypropyl methylcellulose to obtain a soil conditioner for organic-contaminated soil.

[0056] Example 3

[0057] The preparation steps of soil conditioner for organic polluted soil are as follows:

[0058] S1. The biomass (coconut shell) and the nitrogen source (struvite) are mixed uniformly at a mass ratio of 20:1 to obtain a biochar precursor;

[0059] S2, heating the biochar precursor to 600°C at a heating rate of 15°C / min under a nitrogen atmosphere, keeping the temperature for 0.5h, and cooling the mixture to room temperature under a nitrogen atmosphere to obtain nitrogen-doped biochar;

[0060] S3, oscillating and mixing 1 part of the composite bacterial agent and 50 parts of the nitrogen-doped biochar to obtain nitrogen-doped biochar loaded with composite bacteria;

[0061] S4, oscillating and mixing 1 part of the complex enzyme and 20 parts of the mineral additive (diatomaceous earth) to obtain a mineral additive loaded with the complex enzyme;

[0062] S5. Evenly mix the nitrogen-doped biochar loaded with composite bacteria, the mineral additive loaded with composite enzymes and 2 parts of hydroxypropyl methylcellulose to obtain a soil conditioner for organic-contaminated soil.

[0063] Comparative Example 1

[0064] Compared with Example 1, the only difference is that the nitrogen-doped biochar is replaced with ordinary biochar.

[0065] Comparative Example 2

[0066] Compared with Example 1, the only difference is that no composite bacterial agent is added.

[0067] Comparative Example 3

[0068] Compared with Example 1, the only difference is that hydroxypropyl methylcellulose is not added.

[0069] Comparative Example 4

[0070] Compared with Example 1, the only difference is that no mineral additive is added.

[0071] Test example

[0072] A land contaminated by organophosphorus pesticides (OPs) in Ningxia was selected for improvement experiments. Soil at a depth of 0 to 30 cm from the surface was collected with clean tools. After air drying, the soil was extracted with acetonitrile, purified by solid phase extraction, and concentrated by nitrogen blowing. Then, it was quantitatively analyzed by gas chromatography-mass spectrometry. The concentration of pesticides in the samples was obtained by the standard curve of each component. The results are shown in Table 1.

[0073] Table 1

[0074]

[0075] The Ops-contaminated land was divided into 24 plots that did not interfere with each other and were evenly divided into 8 groups. The improvers of Examples 1 to 3 and Comparative Examples 1 to 4 were applied accordingly. The remaining group was not applied with any improver as a control group. The application amount of the improver was 200 kg / mu. After application, the land was rotary tilled to a depth of 30 cm. After rotary tillage, it was plowed and then flooded. The Ops content in the soil was detected again at 5 days, 10 days and 20 days. The results are shown in Tables 2 to 4.

[0076] Table 2 5-day test results

[0077]

[0078] Table 3 10-day test results

[0079]

[0080] Table 4 20-day test results

[0081]

[0082]

[0083] It can be seen from the data in Tables 2 to 4 that the OPs content in the soil will drop significantly in the early stage after the application of the modifier. This is because the enzyme in the modifier interacts with the OPs in the soil after flooding, which makes the OPs content in the early stage drop significantly. In Comparative Example 4, due to the lack of mineral additives, the enzyme is unevenly dispersed, so the efficiency in the improvement process is lower than that of other groups. In Comparative Example 3, due to the lack of hydroxypropyl methylcellulose, the stability of the modifier after application is insufficient compared with Example 1, resulting in a slightly insufficient improvement effect. In Comparative Example 2, no composite bacterial agent was added, and the test results on the 10th and 20th days were significantly worse than those in Example 1. This is because the growth and metabolism of the microorganisms in Example 1 in the later stage promoted the degradation of OPs in the soil. Conventional biochar was used in Comparative Example 1, and the improvement effect was also significantly lower than that in Example 1. This is because it was not nitrogen-doped, and the biochar lacked nitrogen-containing groups, and the adsorption effect on organic pollutants was poorer than that of nitrogen-doped biochar on organic pollutants, which led to the improvement effect of the soil being inferior to that of Example 1 when used as a modifier.

[0084] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0085] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A soil conditioner for organic polluted soil, It is characterized in that By mass, the components include: 20-50 parts of nitrogen-doped biochar, 1-2 parts of composite bacterial agent, 1-2 parts of composite enzyme, 2-5 parts of hydroxypropyl methylcellulose and 10-20 parts of mineral additives; The composite bacterial agent comprises nitrifying bacteria, denitrifying bacteria, Bacillus thuringiensis and acetic acid bacteria in equal mass ratios; The complex enzyme comprises peroxidase, polyphenol oxidase, lyase, dehydrogenase and decarboxylase.

2. The soil conditioner according to claim 1, It is characterized in that The preparation steps of the nitrogen-doped biochar are as follows: The biomass and the nitrogen source are uniformly mixed, and pyrolysis reaction is carried out under a nitrogen atmosphere to prepare nitrogen-doped biochar.

3. The soil conditioner according to claim 2, It is characterized in that The biomass includes crop straw, wood waste or fruit shells.

4. The soil conditioner according to claim 2, It is characterized in that The nitrogen source includes urea, ammonia or struvite.

5. The soil conditioner according to claim 2, It is characterized in that The mass ratio of the biomass to the nitrogen source is 4 to 20:

1.

6. The soil conditioner according to claim 2, It is characterized in that The temperature of the pyrolysis reaction is 400-600° C., the heating rate is 5-15° C., and the time is 0.5-2 h.

7. The soil conditioner according to claim 1, It is characterized in that The mass ratio of the peroxidase, polyphenol oxidase, lyase, dehydrogenase and decarboxylase is 1:1:0.1:0.1:0.

1.

8. The soil conditioner according to claim 1, It is characterized in that The mineral additive includes bentonite or diatomaceous earth.

9. A method for preparing a soil conditioner for organic polluted soil according to any one of claims 1 to 8, comprising the steps of: include: The composite bacterial agent and the nitrogen-doped biochar are shaken and mixed evenly to obtain nitrogen-doped biochar loaded with the composite bacteria; The complex enzyme and the mineral additive are shaken and mixed evenly to obtain the mineral additive loaded with the complex enzyme; The nitrogen-doped biochar loaded with composite bacteria, the mineral additive loaded with composite enzymes and hydroxypropyl methylcellulose are uniformly mixed to obtain the soil conditioner for organic matter-contaminated soil.

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