Environment-friendly soil conditioner for fixing soil chromium and preparation method thereof

Abstract

The invention discloses an environment-friendly soil conditioner for fixing soil chromium and a preparation method thereof, and belongs to the technical field of soil pollution treatment. The soil heavy metal curing agent disclosed by the invention is prepared by activating weathered coal humic acid raw powder, fermenting the activated weathered coal humic acid raw powder, mushroom waste bacteria sticks and straws under the action of a microbial agent and then mixing the fermented materials with an auxiliary agent and an auxiliary agent, and can effectively reduce the content of effective heavy metals in soil, reduce the risk of heavy metal pollution to crops, improve the granular structure of the soil and improve the quality of the soil. The waste mushroom sticks are used as main components for resource reutilization, and the preparation method is low in cost, simple in preparation process, safe, environment-friendly and pollution-free. The fertilizer has the multidirectional effects of fixing metal, improving fertility and transforming agricultural wastes, and has good popularization and application values and great economic and environment-friendly benefits.

Description

Background technology:

[0001] Heavy metals in soil Heavy metal (chromium) and other heavy metal pollution is serious in areas with rapid industrialization and urbanization. For example, heavy metal wastewater, waste gas, waste residue, etc. generated in industrial production processes such as smelting, electroplating, and chemical industry enter farmland soil through atmospheric deposition and wastewater irrigation. Tailings and waste residues generated in mining contain a large amount of heavy metal elements and heavy metals, which enter farmland soil through rainwater erosion and surface runoff. Long-term application of pesticides and fertilizers containing heavy metals, especially phosphate fertilizers and compound fertilizers, as well as unreasonable irrigation and other agricultural activities will also lead to increased heavy metal content in farmland soil. Heavy metal pollution in soil has brought serious harm to the ecological environment and human health. Excessive heavy metals can cause plant physiological dysfunction and nutritional imbalance, affect the normal growth, development and yield of crops, affect the absorption of nutrients such as nitrogen, phosphorus and potassium, and lead to a decrease in agricultural product yield and quality. Heavy metal pollution can destroy the structure of soil microbial communities, affect soil fertility, and thus threaten the stability of the ecosystem. Heavy metals The accumulation of heavy metals in the human body may cause damage to the nervous system, immune system, skeletal system, etc., causing various health problems. Traditional soil heavy metal remediation methods such as chemical leaching, electric remediation, and solidification technology have the disadvantages of high cost, low efficiency, and easy destruction of soil structure. Solidification technology is currently a more commonly used technology. By adding reducing substances, the hexavalent content can be reduced to prevent the migration of chromium into the surrounding environment. At present, ferrous sulfate is commonly used as a reducing agent, but its solidification efficiency is low and affects the physical and chemical properties of the soil. Ferrous sulfate is also easily lost by oxygen in the air and loses its reducing ability. It is impossible to achieve long-term fixation and there is still a risk of chromium pollution, resulting in secondary pollution. Therefore, it is of great significance to develop an efficient, environmentally friendly, and long-lasting soil heavy metal solidifier.

[0002] Advantages of this technology:

[0003] Humic acid (HA) is a natural organic polymer mixture, which comes from coal, lignite, soil and organic matter. It is a soil source substance and contains a large amount of amorphous organic matter such as benzene nucleus, carboxyl, hydroxyl and phenolic hydroxyl. It has the ability to promote the physical, chemical and biological properties of soil, can chelate, complex and bridge with heavy metals to form insoluble precipitates, and has a strong ability to adsorb and solidify heavy metal ions. At the same time, it can also improve soil texture, structure, water retention capacity, cation exchange capacity, pH value, soil organic carbon, enzyme activity, nitrogen cycle and nutrient availability, etc., and has a good effect on enhancing soil fertility and improving soil structure. Therefore, humic acid, as the main heavy metal adsorbent, has the dual effects of fixing heavy metals and improving soil quality.

[0004] Microorganisms are part of the soil. They are tiny organisms that are hard to see with the naked eye. They include bacteria, fungi, archaea, viruses, protozoa, etc. They are widely distributed in nature, including soil, water, air, animals and plants, etc. They participate in the biochemical cycle of the earth and are essential to the ecological balance. They are key substances for improving soil fertility, enhancing soil structural stability, and improving crop resistance. Microorganisms also combine heavy metal ions on the soil surface with negatively charged groups of the bacterial community through interactions such as chelation formation, complex formation, covalent adsorption, and ion exchange, and have the function of degrading heavy metal ions. Microorganisms can also change the properties of heavy metal ions through the physiological and biochemical functions of cells, such as redox reactions in the body. Microorganisms can also react with heavy metal ions to decompose precipitates. In addition, microorganisms can metabolize organic acids such as phosphoric acid, citric acid, and oxalic acid, which can react with heavy metal compounds to accelerate the solidification of heavy metals in the soil. Common bacteria, such as streptomycin, Pseudomonas malignans, Frankla bacteria, Bacillus, etc. and fungi.

[0005] The present invention utilizes the synergistic effect of humic acid and microorganisms to significantly improve the solidification efficiency of heavy metals in soil, reduce the mobility and bioavailability of heavy metals in soil, and at the same time improve the soil ecological environment, increase soil fertility, and promote plant growth and development. Since the curing agent uses waste mushroom sticks, it can reduce the preparation cost and reuse them as resources, and will not cause secondary pollution to the environment and soil, which is beneficial to crop growth, has high environmental ecology and economic value, and provides a novel design idea for the restoration and management of heavy metal contaminated soil, and has broad market prospects and good ecological and environmental benefits. Summary of the invention:

[0006] (1) Mix the weathered coal humic acid powder with 20%-30% sulfuric acid and phosphoric acid mixed acid in a mass ratio of (5--8):1, stir evenly and seal, activate at room temperature for 12-16 hours, and grind to obtain activated humic acid.

[0007] (2) The spent mushroom sticks and straw are crushed by crushing equipment respectively, so that the average particle size of the spent mushroom stick residue and the length of the straw are less than 1 mm, and then mixed evenly with activated humic acid. The mass ratio of the three materials is (20-30): (20-30): (40-50), and a mixed fermentation product precursor is obtained.

[0008] (3) adding a microbial agent with an effective viable count of 200-500 million / g to the mixed fermentation product precursor, the added amount being 0.01-0.05% of the mixed fermentation product precursor, and adding water so that the mixed fermentation product precursor contains 50-60% water, piling the fermentation product precursor material into a trapezoidal or conical shape, covering the top with a layer of cotton quilt for moisture retention, heat preservation and air permeability, turning the pile once every 1-3 days, controlling the temperature to reach 50-60° C., flattening the pile after fermentation for 10-15 days, naturally drying and then crushing to obtain a microbial-loaded humic acid main agent;

[0009] (4) The main agent, auxiliary agent and adjuvant loaded with microbial humic acid are uniformly mixed in a mass ratio of (80-90): (5--10): (5-10) to prepare a soil heavy metal pollution solidifying agent loaded with microbial humic acid. Description of the drawings:

[0010] Figure 1 This is an infrared spectrum of activated humic acid for an environmentally friendly soil conditioner for fixing soil chromium and its preparation method proposed in the present invention;

[0011] Figure 2 This is a scanning electron microscope appearance picture of a curing agent for fixing soil chromium and an environmentally friendly soil conditioner and a preparation method thereof proposed in the present invention;

[0012] Figure 3 A diagram showing soil MWD and GMD and the amount of curing agent added for an environmentally friendly soil conditioner for fixing soil chromium and a preparation method thereof proposed in the present invention;

[0013] Figure 4 This is a graph showing the relationship between the effective content of heavy metals in soil and time in the presence of a curing agent for an environmentally friendly soil conditioner for fixing soil chromium and a preparation method thereof proposed in the present invention. Specific implementation method:

[0014] Embodiment 1:

[0015] (1) The weathered coal humic acid raw powder containing 62.8% humic acid is mixed with 20% sulfuric acid and phosphoric acid mixed acid in a mass ratio of 8:1, stirred evenly and sealed, activated at room temperature for 12 hours, and crushed to obtain activated humic acid.

[0016] (2) The spent mushroom sticks of Pleurotus eryngii and rice straw were crushed by crushing equipment respectively, so that the average particle size of the spent mushroom stick residue and the length of the straw were less than 1 mm, and then mixed evenly with activated humic acid, and the mass ratio of the three materials was 30:20:50, to obtain a mixed fermentation product precursor.

[0017] (3) adding a microbial agent with an effective viable count of 200 million / g to the mixed fermentation product precursor, the added amount being 0.03% of the mixed fermentation product precursor, and adding water to make the mixed fermentation product precursor contain 60% water, piling the fermentation product precursor material into a trapezoidal shape, covering it with a layer of quilt, turning the pile once every 2 days, controlling the temperature to 50-60° C., flattening the pile after 15 days of fermentation, naturally drying it, and then crushing it to obtain a microbial-loaded humic acid main agent;

[0018] (4) The main agent, auxiliary agent and adjuvant loaded with microbial humic acid are mixed evenly in a mass ratio of 90:5:5 to prepare a soil heavy metal pollution solidifying agent loaded with microbial humic acid.

[0019] Example 2

[0020] (1) The weathered coal humic acid powder containing 40.5% humic acid is mixed with 30% sulfuric acid and phosphoric acid mixed acid in a mass ratio of 5:1, stirred evenly and sealed, activated at room temperature for 16 hours, and crushed to obtain activated humic acid.

[0021] (2) The spent mushroom sticks of Pleurotus eryngii and rice straw were crushed by crushing equipment respectively, so that the average particle size of the spent mushroom stick residue and the length of the straw were less than 1 mm, and then mixed evenly with activated humic acid, and the mass ratio of the three materials was 30:30:40, to obtain a mixed fermentation product precursor.

[0022] (3) adding a microbial agent with an effective viable count of 200 million / g to the mixed fermentation product precursor, the added amount being 0.05% of the mixed fermentation product precursor, and adding water to make the mixed fermentation product precursor contain 50% water, piling the fermentation product precursor material into a trapezoidal shape, covering it with a layer of quilt, turning the pile once every 2 days, controlling the temperature to 50-60° C., flattening the pile after 15 days of fermentation, naturally drying it, and then crushing it to obtain a microbial-loaded humic acid main agent;

[0023] (4) The main agent, auxiliary agent and adjuvant loaded with microbial humic acid are mixed evenly in a mass ratio of 80:10:10 to prepare a soil heavy metal pollution solidifying agent loaded with microbial humic acid.

[0024] Example 3

[0025] (1) The weathered coal humic acid powder containing 55.1% humic acid is mixed with 25% sulfuric acid and phosphoric acid mixed acid in a mass ratio of 6:1, stirred evenly and sealed, activated at room temperature for 14 hours, and crushed to obtain activated humic acid.

[0026] (2) The spent mushroom sticks and wheat straw were crushed by crushing equipment respectively, so that the average particle size of the spent mushroom stick residue and the straw length were less than 1 mm, and then mixed evenly with activated humic acid, with the mass ratio of the three materials being 25:25:50, to obtain a mixed fermentation product precursor.

[0027] (3) adding a microbial agent with an effective viable count of 200 million / g to the mixed fermentation product precursor, the added amount being 0.05% of the mixed fermentation product precursor, and adding water to make the mixed fermentation product precursor contain 55% water, piling the fermentation product precursor material into a trapezoidal shape, covering it with a layer of quilt, turning the pile once every 2 days, controlling the temperature to 50-60° C., flattening the pile after 13 days of fermentation, naturally drying it, and then crushing it to obtain a microbial-loaded humic acid main agent;

[0028] (4) The main agent, auxiliary agent and adjuvant loaded with microbial humic acid are mixed evenly in a mass ratio of 85:5:10 to prepare a soil heavy metal pollution solidifying agent loaded with microbial humic acid.

[0029] Example 4

[0030] ((1) Mix 62.8% humic acid raw powder of weathered coal humic acid with 25% sulfuric acid and phosphoric acid mixed acid in a mass ratio of 8:1, stir evenly and seal, activate at room temperature for 12 hours, and grind to obtain activated humic acid.

[0031] (2) The spent mushroom sticks and corn stalks were crushed by crushing equipment respectively, so that the average particle size of the spent mushroom stick residue and the length of the stalks were less than 1 mm, and then mixed evenly with activated humic acid, with the mass ratio of the three materials being 30:20:50, to obtain a mixed fermentation product precursor.

[0032] (3) adding a microbial agent with an effective viable count of 200 million / g to the mixed fermentation product precursor, the added amount being 0.07% of the mixed fermentation product precursor, and adding water to make the mixed fermentation product precursor contain 60% water, piling the fermentation product precursor material into a cone shape, covering it with a layer of quilt, turning the pile once every 3 days, controlling the temperature to 50-60° C., flattening the pile after 15 days of fermentation, naturally drying it, and then crushing it to obtain a microbial-loaded humic acid main agent;

[0033] (4) The main agent, auxiliary agent and adjuvant loaded with microbial humic acid are mixed evenly in a mass ratio of 85:10:5 to prepare a soil heavy metal pollution solidifying agent loaded with microbial humic acid.

[0034] Example 5

[0035] (1) The weathered coal humic acid raw powder containing 55.1% humic acid is mixed with 20% sulfuric acid and phosphoric acid mixed acid in a mass ratio of 8:1, stirred evenly and sealed, activated at room temperature for 14 hours, and crushed to obtain activated humic acid.

[0036] (2) Pleurotus eryngii waste spawn and wheat straw were crushed by crushing equipment respectively, so that the average particle size of the waste spawn residue and the straw length were less than 1 mm, and then mixed evenly with activated humic acid, with the mass ratio of the three materials being 25:25:50, to obtain a mixed fermentation product precursor.

[0037] (3) adding a microbial agent with an effective viable count of 200 million / g to the mixed fermentation product precursor, the added amount being 0.01% of the mixed fermentation product precursor, and adding water to make the mixed fermentation product precursor contain 50% water, piling the fermentation product precursor material into a cone shape, covering it with a layer of quilt, turning the pile once every 3 days, controlling the temperature to 50-60° C., flattening the pile after 15 days of fermentation, naturally drying it, and then crushing it to obtain a microbial-loaded humic acid main agent;

[0038] (4) The main agent, auxiliary agent and adjuvant loaded with microbial humic acid are mixed evenly in a mass ratio of 80:10:10 to prepare a soil heavy metal pollution solidifying agent loaded with microbial humic acid.

[0039] Example 6

[0040] (1) The raw powder of weathered coal humic acid containing 40.5% humic acid is mixed with 30% sulfuric acid and phosphoric acid mixed acid in a mass ratio of 8:1, stirred evenly and sealed, activated at room temperature for 16 hours, and crushed to obtain activated humic acid.

[0041] (2) Pleurotus eryngii waste mushroom sticks and wheat straw were crushed by crushing equipment respectively, so that the average particle size of the waste mushroom stick residue and the straw length were less than 1 mm, and then mixed evenly with activated humic acid, with the mass ratio of the three materials being 30:25:45, to obtain a mixed fermentation product precursor.

[0042] (3) adding a microbial agent with an effective viable count of 200 million / g to the mixed fermentation product precursor, the added amount being 0.04% of the mixed fermentation product precursor, and adding water to make the mixed fermentation product precursor contain 50% water, piling the fermentation product precursor material into a cone shape, covering it with a layer of quilt, turning the pile once every 3 days, controlling the temperature to 50-60° C., flattening the pile after 12 days of fermentation, naturally drying it, and then crushing it to obtain a microbial-loaded humic acid main agent;

[0043] (4) The main agent, auxiliary agent and adjuvant loaded with microbial humic acid are mixed evenly in a mass ratio of 90:2:8 to prepare a soil heavy metal pollution solidifying agent loaded with microbial humic acid.

[0044] Example 7

[0045] (1) The weathered coal humic acid powder containing 40.5% humic acid is mixed with 30% sulfuric acid and phosphoric acid mixed acid in a mass ratio of 5:1, stirred evenly and sealed, activated at room temperature for 16 hours, and crushed to obtain activated humic acid.

[0046] (2) The spent mushroom sticks of Pleurotus eryngii and corn stalks were crushed by crushing equipment respectively, so that the average particle size of the spent mushroom stick residue and the length of the stalks were less than 1 mm, and then mixed evenly with activated humic acid, with the mass ratio of the three materials being 25:30:45, to obtain a mixed fermentation product precursor.

[0047] (3) adding a microbial agent with an effective viable count of 500 million / g to the mixed fermentation product precursor, the added amount being 0.06% of the mixed fermentation product precursor, and adding water to make the mixed fermentation product precursor contain 50% water, piling the fermentation product precursor material into a cone shape, covering it with a layer of quilt, turning the pile once every 2 days, controlling the temperature to 50-60° C., flattening the pile after 12 days of fermentation, naturally drying it, and then crushing it to obtain a microbial-loaded humic acid main agent;

[0048] (4) The main agent, auxiliary agent and adjuvant loaded with microbial humic acid are mixed evenly in a mass ratio of 80:10:10 to prepare a soil heavy metal pollution solidifying agent loaded with microbial humic acid.

[0049] Example 8

[0050] (1) The weathered coal humic acid raw powder containing 55.1% humic acid is mixed with 20% sulfuric acid and phosphoric acid mixed acid in a mass ratio of 5:1, stirred evenly and sealed, activated at room temperature for 14 hours, and crushed to obtain activated humic acid.

[0051] (2) The spent mushroom sticks and wheat straw were crushed by crushing equipment respectively, so that the average particle size of the spent mushroom stick residue and the straw length were less than 1 mm, and then mixed evenly with activated humic acid, with the mass ratio of the three materials being 30:30:40, to obtain a mixed fermentation product precursor.

[0052] (3) adding a microbial agent with an effective viable count of 500 million / g to the mixed fermentation product precursor, the added amount being 0.01% of the mixed fermentation product precursor, and adding water to make the mixed fermentation product precursor contain 50% water, piling the fermentation product precursor material into a cone shape, covering it with a layer of quilt, turning the pile once every 3 days, controlling the temperature to 50-60° C., flattening the pile after 15 days of fermentation, naturally drying it, and then crushing it to obtain a microbial-loaded humic acid main agent;

[0053] (4) The main agent, auxiliary agent and adjuvant loaded with microbial humic acid are mixed evenly in a mass ratio of 85:8:7 to prepare a soil heavy metal pollution solidifying agent loaded with microbial humic acid.

[0054] Example results:

[0055] Table 1 Effect of microbial humic acid-loaded soil heavy metal pollution solidifier on chromium solidification

[0056]

[0057]

[0058] It can be seen from the above table that the soil chromium solidification rate of the embodiments of the present invention is 72.2-81.7%, which can greatly reduce the risk of crops absorbing chromium during their growth, and can also achieve in-situ solidification and remediation of heavy metal-contaminated soil.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid, characterized in that The main steps of preparation are as follows: (1) Mix weathered coal powder with a humic acid content of 40.5-62.8% with a mixed acid of 20%-30% sulfuric acid and phosphoric acid in a mass ratio of (5--8):1, with the volume ratio of sulfuric acid to phosphoric acid being 3:1, stir evenly and seal, activate at room temperature for 12-16 hours, and grind to obtain activated humic acid. (2) The spent mushroom sticks and straw are crushed by crushing equipment respectively, so that the average particle size of the spent mushroom stick residue and the straw length are less than 1 mm, and then mixed evenly with activated humic acid. The mass ratio of the three materials is (20-30):(20-30):(40-50), and a mixed fermentation product precursor is obtained. (3) Add a microbial agent with an effective viable count of 200-500 million / g to the mixed fermentation product precursor, the added amount being 0.01-0.05% of the mixed fermentation product precursor, and add water so that the mixed fermentation product precursor contains 50-60% water. (4) Pile the fermentation product precursor material into a trapezoidal or conical shape, cover it with a layer of moisture-retaining, heat-insulating and breathable material such as a quilt, turn the pile once every 1-3 days, control the temperature to 50-60° C., flatten the pile after 10-15 days of fermentation, dry it naturally and then crush it to obtain the loaded microbial humic acid main agent; (5) The microbial humic acid-loaded main agent, auxiliary agent, and adjuvant are uniformly mixed in a mass ratio of (80-90):(5-10):(5-10) to prepare a microbial humic acid-loaded soil heavy metal solidifying agent.

2. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that The humic acid content in weathered coal raw powder is 40.5-62.8%.

3. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that When preparing activated humic acid, the mass ratio of weathered coal powder to mixed acid is (5--8):

1.

4. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that The volume ratio of sulfuric acid to phosphoric acid is 3:1, and the concentration of mixed acid is 20%-30%.

5. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that The reaction conditions for activated humic acid are sealing and activating at room temperature for 12-16 hours.

6. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that: The waste mushroom sticks are one or more of shiitake mushrooms, white jade mushrooms, king oyster mushrooms, etc.; the straws are straws of rice, wheat, corn, etc.

7. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that: The microorganisms include Bacillus subtilis, Streptomycin, Bacillus licheniformis, Lactobacillus plantarum, yeast and fungi, with an effective live bacteria count of 200-500 million / g.

8. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that: The mass ratio of the three materials, namely, waste mushroom stick residue, straw and activated humic acid in the mixed fermentation product is (20-30):(20-30):(40-50).

9. The method for preparing a soil heavy metal pollution solidifying agent loaded with microbial humic acid according to claim 1, characterized in that: The amount of microbial agent added to the main agent of loaded microbial humic acid is 0.01-0.05% of the mixed fermentation product.

10. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that: The pile loaded with microbial humic acid main agent is turned over once every 1-3 days, the temperature is controlled to 50-60℃, and fermented for 10-15 days.

11. The method for preparing a soil heavy metal pollution solidifying agent loaded with microbial humic acid according to claim 1, characterized in that: The mass ratio of the main agent, auxiliary agent and additive of the loaded microbial humic acid is (80-90):(5-10):(5-10).

12. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that: The auxiliary agent is one of superphosphate, phosphogypsum and double superphosphate.

13. The method for preparing a soil heavy metal solidifying agent loaded with microbial humic acid according to claim 1, characterized in that: The auxiliary agent is potassium dihydrogen phosphate.

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