Bactericide and reducing bacterium coupled remediation material for inhibiting acidification of coal gangue and use thereof

Abstract

A bactericide and reducing bacterium coupled remediation material for inhibiting acidification of coal gangue and a use thereof. The remediation material is a composite material for inhibiting acidification of coal gangue, which is formed by adsorbing a reducing bacterium by biochar to form an immobilized microbial inoculum, and then mixing the immobilized microbial inoculum with a bactericide with a sustained-release function at a volume ratio of 1:10-20, the reducing bacterium being 5-10 ml of sulfate reducing bacterium, and the bactericide being 50-100 mg / L of sodium dodecyl sulfate solution. The remediation material can remediate a coal gangue dump having the pH of 4-6, achieves the acid production inhibition effect of 80% or more and the pH value of 6.0 or more, involves simple operate, low cost, long effective time and visual effect, and has important scientific values for promoting acidification pollution remediation of a waste dump in a coal mine area and land reclamation and ecological restoration work.

Description

A bactericide and reducing bacteria coupled repair material for inhibiting coal gangue acidification and its application Technical Field

[0001] The present invention belongs to the field of mine pollution remediation technology and application, and particularly relates to a bactericide and reducing bacteria coupling remediation material for inhibiting coal gangue acidification and application thereof. Background Art

[0002] With the development of coal resources, large quantities of gangue have accumulated, becoming my country's largest source of industrial solid waste in terms of both annual emissions and cumulative stockpiles. Currently, gangue is primarily stored in piles, gradually forming gangue mountains. The open-air storage and stacking structure of gangue mountains hinder heat dissipation, causing internal heat to accumulate over time. When the temperature reaches the critical combustion point, the carbonaceous materials in the gangue spontaneously combust. Spontaneously combusting gangue mountains emit large quantities of harmful gases and dust, such as SO2, CO2, CO, and H2S. Furthermore, the acidic leaching water causes acidification pollution in the surrounding soil, leading to the death of vegetation around mining areas and severely impacting water quality, soil, and air in and around the mining areas. The heavy metal ions released by the acidic wastewater pose a threat to human health.

[0003] The pH value of newly discharged gangue is generally neutral or even alkaline. However, upon contact with air, oxidation reactions occur, and long-term storage of gangue can lead to acidification. To prevent gangue spontaneous combustion and pollution, coal mines have implemented various gangue fire prevention measures, the most common of which is covering fire prevention. This involves covering the surface of the gangue pile with inert materials such as loess, blocking oxygen from reaching the gangue and thus reducing the rate of oxidation. In practical application, covering has been found to have the advantages of simple construction and low cost, but the large amount of work and long construction period make it unsuitable as a fire prevention measure for temporary gangue storage. Given the time-consuming and labor-intensive firefighting efforts once gangue piles heat up and spontaneously combust, as well as the risk of re-ignition, scholars at home and abroad have focused on source control technologies for acidic gangue pile pollution.

[0004] Oxidizing bacteria biocatalyze the oxidation of sulfur compounds in coal gangue. These bacteria, primarily represented by Acidithiobacillus ferrooxidans, can significantly increase the rate of oxidation of ferrous ions to ferric ions, making them a key cause of coal gangue acidification pollution. Fungicides can significantly affect the activity of environmental microorganisms and their behavior within the environment. Domestic and international scholars have found that fungicide technology can be used to inhibit oxidation and acid production in the management of coal gangue heaps. Fungicides also have different release mechanisms, so a slow-release material that matches the applied fungicide should be selected. Water-retaining agents are insoluble in water, non-toxic, odorless, and harmless, can be reused, are inexpensive, absorb fertilizers and pesticides, and then slowly release them, and are self-biodegradable.

[0005] Sulfate-reducing bacteria (SRB) are bacteria that can utilize sulfate and other oxidized sulfides, or elemental sulfur as an electron acceptor, and reduce these substances to S 2- In recent years, researchers have used SRB to remediate acidic pollution from coal gangue oxidation, achieving some success in the in-situ remediation of spontaneous combustion coal gangue pile pollution. However, gangue piles are located in an open, open-air environment, and SRB can only survive by attaching to the gangue surface. The relatively poor habitat of gangue piles, lacking organic matter for SRB to utilize, makes it difficult to directly introduce sulfate-reducing bacteria, which suppresses their activity and limits the application of this technology. Upon contact with native bacterial flora, introduced sulfate-reducing bacteria may face competition and inhibition from native microorganisms, resulting in decreased activity and reduced treatment efficiency. Therefore, solidifying materials are required to provide the reducing bacteria with the nutrients they need to grow. Fungicides kill the native flora, reducing their competitiveness and creating conditions for sulfate-reducing bacteria to thrive. Biochar, with its strong adsorption capacity, large specific surface area, and stable chemical properties, provides a viable environment for microorganisms.

[0006] Summary of the Invention

[0007] In response to the shortcomings of the existing technology, the present invention provides a fungicide and reducing bacteria coupled composite material for inhibiting coal gangue acidification and its application, which can inhibit coal gangue acidification and achieve long-term treatment effects. It also has the advantages of strong on-site operability, low price, long timeliness and good treatment effect.

[0008] In order to solve the problems of the prior art, the technical solution adopted by the present invention is:

[0009] A composite material for inhibiting the acidification of coal gangue and coupled with reducing bacteria comprises the following steps: biochar adsorbs reducing bacteria to form a solidifying bacterial agent; a water-retaining agent is added to a bactericide solution to form a bactericide with a sustained-release function; and the solidifying bacterial agent and the bactericide with a sustained-release function are mixed in a volume ratio of 1:10-20 to form a composite material for inhibiting the acidification of coal gangue. The reducing bacteria are 5-10 ml of sulfate-reducing bacteria, and the bactericide is a 50-100 mg / L sodium dodecyl sulfate solution.

[0010] As an improvement, the biochar is corn straw biochar.

[0011] As an improvement, the solidifying bacterial agent is mixed with the fungicide with a slow-release function in a volume ratio of 1:20.

[0012] As an improvement, the water-retaining agent is polyacrylamide.

[0013] The application of the above-mentioned fungicide for inhibiting coal gangue acidification and reducing bacteria coupled composite material in acidic coal gangue storage yards.

[0014] As an improvement, the pH of the acidic coal gangue dump is 4-6.

[0015] As an improvement, the specific application steps are: the application rate of the fungicide and reducing bacteria coupling composite material for inhibiting coal gangue acidification to the coal gangue is 1L / m 2 ~4L / m 2 After use, it effectively removes sulfate ions in acidic coal gangue, reduces the salt content of coal gangue, increases the pH value of coal gangue, and changes the microbial bacterial community structure of coal gangue. Beneficial effects:

[0016] Based on the remediation of acidic coal gangue by coupling reducing bacteria with a bactericide, the present invention uses biochar to adsorb sulfate-reducing bacteria, and slowly releases the bactericide and water-retaining agent to prepare a composite material with a slow-release effect. The bactericide severely damages the cell membrane of the oxidizing bacteria and destroys the cell wall, causing intracellular proteins to overflow into the bacterial solution and lipids to flow out, destroying the internal structure of the bacteria and effectively reducing the acidification trend of the coal gangue. The undamaged reducing bacteria play a role in the remediation process, and the coupling with the bactericide improves the living environment of the sulfate-reducing bacteria while achieving thorough and long-term inhibition of the oxidizing bacteria. The synergistic effect ensures that the composite material effectively repairs the acid pollution in the coal gangue yard and efficiently repairs environmental problems such as high-salt acid wastewater and heavy metal dissolution generated by coal gangue acidification.

[0017] In addition, the preparation method of the present invention is simple, easy to operate, time-saving, low-cost and has good effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a scanning electron microscope image of reducing bacteria in a composite material of a fungicide and reducing bacteria coupled with the fungicide for inhibiting coal gangue acidification prepared by the present invention.

[0019] FIG2 is a scanning electron microscope image of reducing bacteria after the composite material of the fungicide for inhibiting coal gangue acidification and reducing bacteria of the present invention is applied to coal gangue.

[0020] FIG3 shows the pH regulation effect of the gangue leachate within 30 days with and without application (CK) of the fungicide for inhibiting coal gangue acidification prepared by the present invention and the reducing bacteria coupled composite material.

[0021] FIG4 shows the sulfate reduction effect of the gangue leachate within 30 days with and without application (CK) of the composite material of the fungicide for inhibiting coal gangue acidification prepared by the present invention and the reducing bacteria coupling.

[0022] FIG5 shows the control effect of the conductivity of the gangue leachate within 30 days with and without application (CK) of the fungicide for inhibiting coal gangue acidification prepared by the present invention and the reducing bacteria coupled composite material. DETAILED DESCRIPTION

[0023] The liquid culture medium for sulfate-reducing bacteria is as follows:

[0024] Weigh 1 g of Na2SO4, 0.5 g of K2HPO4, 2 g of MgSO4·7H2O, 2 g of CaCl2·2H2O, 2 g of sodium lactate, and 1 g of yeast extract, dissolve them in deionized water, and adjust the volume to 1 L. Sterilize in a high-temperature and high-pressure sterilizer at 121°C for 30 min.

[0025] After inoculation with SRB bacterial solution, nitrogen exposure treatment was carried out, and then sealed and cultured in a constant temperature incubator at 30°C, and then the following acclimation operations were carried out.

[0026] The specific domestication process is as follows

[0027] 1) Inoculate the sealed culture of sulfate-reducing bacteria into sterilized culture medium. Seal the bottle with sealing film and incubate at 30°C for 4 days. The sulfate-reducing bacteria will enter the logarithmic growth phase. At this point, black ferrous sulfide will appear in the solution, hydrogen sulfide will escape from the solution, and an odor similar to rotten eggs will be detected at the bottle mouth, indicating that the sulfate-reducing bacteria have grown in the culture medium.

[0028] 2) Add 1 ml of logarithmic-phase sulfate-reducing bacteria to the culture medium, seal the bottle with 5 ml of sterile paraffin solution, and incubate anaerobically at 30°C for 4 days, repeating 3 times to remove oxidative bacteria.

[0029] 3) The enriched culture fluid was streaked onto the surface of a solid culture medium (the solid culture medium formula is: K2HPO4 0.5 g; (NH4)2SO4 2.5 g; NaHCO3 0.5 g; CaCl2 0.2 g; MgSO4 1.0 g; sodium lactate 2.0 mL; ascorbic acid 0.1 g; cysteine ​​hydrochloride 0.5 g; yeast extract 1.5 g; (NH4)2Fe(SO4)2 0.5 g; deionized water 1000 mL. 2% agar powder was added to the prepared culture medium to prepare the solid culture medium). After incubation at 30°C for 5-7 days, a single colony was picked from the end of the streak and inoculated into liquid culture medium and cultured until the logarithmic phase (the bacterial culture turns ink-colored and has a rotten egg odor).

[0030] 4) Transfer the culture solution into an anaerobic chamber and continue culturing under the same conditions as in step 3);

[0031] 5) Repeating the operations of step 3) and step 4) to achieve aerobic-anaerobic alternating cycles until facultative anaerobic sulfate-reducing bacteria are obtained after anaerobic culture.

[0032] Preparation of biochar: Corn straw biochar was prepared by pyrolysis carbonization in a Mabo furnace. The pyrolysis carbonization used slow pyrolysis of corn straw with a heating rate of 3°C / min and a heating time of 4 h.

[0033] Preparation of curing agent: 0.1 g corn straw biochar was placed in 5 mL of acclimated facultative anaerobic sulfate-reducing bacteria at 8000 r / min. -1 Centrifuge for 10 minutes, discard the supernatant, wash the lower precipitate with 1% saline, centrifuge and repeat washing three times, and the solid obtained by centrifugation is the solidified bacterial agent.

[0034] Bactericide with sustained-release function: 1g of water-retaining agent is added into 100ml of 50mg / L sodium lauryl sulfate solution and mixed, wherein the water-retaining agent is polyacrylamide.

[0035] The preparation method of the composite material of fungicide and reducing bacteria coupling for inhibiting coal gangue acidification is as follows: 0.1g of biochar adsorbs 5ml of sulfate-reducing bacteria liquid and 1g of water-retaining agent slowly releases 100ml of 50mg / L sodium dodecyl sulfate solution.

[0036] Figure 1 is a scanning electron micrograph of reducing bacteria in a composite material of a fungicide and reducing bacteria coupled to inhibit coal gangue acidification, prepared according to the present invention. Figure 2 is a scanning electron micrograph of reducing bacteria after the composite material of a fungicide and reducing bacteria coupled to inhibit coal gangue acidification according to the present invention was applied to coal gangue. Figures 1 and 2 demonstrate that the fungicide and reducing bacteria are fully coupled, allowing the intact reducing bacteria to function during repair.

[0037] The fungicide for inhibiting coal gangue acidification and the reducing bacteria coupled composite material prepared by the present invention were applied to coal gangue with a pH of 4.2 at a rate of 100 ml per 100 g of coal gangue. 100 ml of distilled water was added at different time points, the coal gangue leachate was collected, and the pH, sulfate concentration, and conductivity of the leachate were measured.

[0038] Figure 3 shows the pH regulation of gangue leachate solutions over a 30-day period after application and after application of the composite material prepared by the present invention, which is coupled with a fungicide and reducing bacteria to inhibit gangue acidification. The figure shows that as the composite material is applied to the gangue over a longer period of time, the pH increases within 10 days, reaching a peak on the 10th day and remaining stable for 30 days.

[0039] Figure 4 shows the sulfate reduction effect of the gangue leachate over a 30-day period after application and after application of the composite material prepared by the present invention, which combines a fungicide and reducing bacteria to inhibit gangue acidification. As shown in Figure 4, as the composite material is applied to the gangue over a longer period of time, the sulfate concentration decreases over the course of 10 days, reaching its lowest value on the 10th day and remaining stable over the entire 30-day period. The composite material effectively inhibits gangue acidification.

[0040] Figure 5 shows the conductivity regulation of the leachate solution in gangue over a 30-day period after application of the composite material prepared by the present invention, a fungicide and reducing bacteria coupling agent for inhibiting gangue acidification. The figure shows that as the composite material is applied to the gangue for an extended period, the EC value decreases after approximately 10 days and remains stable over the 30-day period. In the experiment without the composite material, the pH decreases, the sulfate concentration increases, and the EC value also tends to increase, indicating gangue acidification.

[0041] In summary, when the fungicide for inhibiting coal gangue acidification and the reducing bacteria coupled composite material of the present invention act on coal gangue, it shows a strong inhibitory effect within 30 days, the acid production inhibition effect reaches more than 80%, and the pH value reaches more than 6.0. It can effectively inhibit the acidification of coal gangue, has the advantages of simple operation, low cost, long effective time, intuitive effect, etc., and has good application effect.

Claims

1. A composite material of a bactericide and reducing bacteria coupled to inhibit acidification of coal gangue, characterized in that: The composite material of the fungicide and reducing bacteria coupling for inhibiting the acidification of coal gangue refers to biochar adsorbing reducing bacteria to form a solidifying bacterial agent, adding a water retaining agent to the fungicide solution to form a fungicide with a sustained-release function, and then mixing the solidifying bacterial agent and the fungicide with a sustained-release function in a volume ratio of 1:10-20 to form a composite material for inhibiting the acidification of coal gangue, the reducing bacteria are 5-10 ml of sulfate-reducing bacteria, and the fungicide is 50-100 mg / L of sodium dodecyl sulfate solution.

2. The bactericide and reducing bacteria coupling composite material for inhibiting coal gangue acidification according to claim 1, characterized in that: The biochar is corn straw biochar.

3. The bactericide and reducing bacteria coupling composite material for inhibiting coal gangue acidification according to claim 1, characterized in that: The solidifying bacterial agent and the fungicide with a slow-release function are mixed in a volume ratio of 1:

20.

4. The bactericide and reducing bacteria coupling composite material for inhibiting coal gangue acidification according to claim 1, characterized in that: The water retaining agent is polyacrylamide.

5. Application of the bactericide for inhibiting coal gangue acidification and the reducing bacteria coupled composite material according to claim 1 in an acidic coal gangue dump.

6. The use according to claim 5, characterized in that: The pH of the acidic coal gangue dump is 4-6.

7. The use according to claim 5, characterized in that: The specific steps of the application are: the application amount of the bactericide and reducing bacteria coupling composite material for inhibiting the acidification of coal gangue to the coal gangue is 1L / m 2 -4L / m 2 After use, it can effectively remove sulfate ions in acidic coal gangue, reduce the salt content of coal gangue, increase the pH value of coal gangue, and change the microbial bacterial community structure of coal gangue.

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