High-humus coal gangue-based bionic peat as well as preparation method and application thereof

Abstract

The invention provides high-humus coal gangue-based bionic peat as well as a preparation method and application thereof, the preparation method comprises the following steps: (1) inoculating a soil bacterial suspension into a lignin screening liquid culture medium for enrichment culture to obtain a high-temperature-resistant bacterial solution H1; and (2) transferring the high-temperature-resistant bacterial liquid H1 into a coal gangue and garden waste mixed substrate culture medium, adding Tween 80 for fermentation, and drying to obtain the high-humus coal gangue-based bionic peat, the fermentation time is 20 to 35 days. According to the preparation method disclosed by the invention, the coal gangue-based bionic peat with high humus content can be simply and quickly obtained, the high-humus coal gangue-based bionic peat can be used for repairing various soils, and resource utilization is realized while the problem that a large amount of coal gangue and garden wastes are accumulated is solved.

Description

Technical Field

[0001] This invention relates to the field of soil remediation technology, and in particular to a high-humus coal gangue-based biomimetic peat, its preparation method, and its application. Background Technology

[0002] After rare earth mining employs in-situ leaching, residual (NH4)2SO4 in the leachate can cause soil acidification, nutrient loss, structural damage, and compaction. A key aspect of mine ecological reconstruction is restoring the soil's physical structure (such as soil aggregates, aeration, and water retention), chemical properties (such as pH and nutrient content), and biological characteristics (such as microbial communities) to provide the necessary substrate conditions for plant growth. Currently, soil remediation in ion-adsorption rare earth mining areas mainly includes physical remediation, bioremediation, and chemical remediation. Among these, chemical remediation is a highly practical and effective technique for mine remediation.

[0003] Coal gangue is an industrial solid waste generated during coal mining and washing, a byproduct of coal production, with an annual output of 600-800 million tons. Due to the inability to dispose of it in large quantities, the annual accumulation can reach 200-300 million tons. The large-scale accumulation of coal gangue not only occupies land but also causes many environmental problems. Coal gangue contains approximately 20% lignin-like organic matter and some mineral-derived humic acid, is rich in porous structures, and contains various trace elements and nutrients essential for plant growth. Therefore, it can be utilized as a mine soil remediation agent.

[0004] CN119191914A discloses a coal gangue organic fertilizer and its preparation method. The coal gangue organic fertilizer is made by uniformly mixing modified coal gangue, agricultural and forestry waste, and microbial agents, followed by high-temperature aerobic composting and aging. However, before fermentation, this method requires pretreatment of the coal gangue, including ball milling, oxidant soaking, and ultrasonic treatment, which increases the cost of preparing the fertilizer and makes the preparation method complex. Furthermore, it requires two stages: fermentation and composting, with a long fermentation time of up to 50 days.

[0005] CN120464406A discloses a soil ecological restoration agent based on coal gangue-fly ash and its preparation method. The soil ecological restoration agent, by weight, comprises the following components: 40-50 parts of a mixed powder of coal gangue and fly ash, 6-12 parts of microbial inoculant, 15-20 parts of humic acid, 6-12 parts of sodium polyacrylate, 8-12 parts of straw charcoal, 20-25 parts of bentonite, and 4-6 parts of aluminum sulfate. However, this soil ecological restoration agent requires the additional addition of humic acid, resulting in high preparation costs.

[0006] CN111792952A discloses activated coal gangue powder, activated coal gangue mineral fertilizer, and their preparation methods. The activated coal gangue powder is obtained by mixing and grinding the following raw materials: 80%~90% coal gangue, 1.0%~10.0% sugar industry waste residue, 1.0%~10.0% organic acid, 0.5%~3.0% alkanolamines, 0.4%~4.0% polar additives, 0.5%~3.0% dispersant, 0.5%~3.0% surfactant, and 1.0%~10.0% activator. However, the preparation of this activated coal gangue mineral fertilizer requires the addition of organic acid, alkanolamines, polar additives, dispersant, surfactant, and activator, resulting in high preparation costs.

[0007] Therefore, it is of great significance to develop a coal gangue-based biomimetic peat with low preparation cost and high humus content for soil remediation in mining areas. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention provides a high-humicity coal gangue-based biomimetic peat, its preparation method and application. Using coal gangue and garden waste as raw materials, high-humicity coal gangue-based biomimetic peat is synthesized by adding thermophilic bacteria and Tween 80. This can reduce the pressure on the environment caused by the large accumulation of coal gangue and garden waste. The prepared high-humicity coal gangue-based biomimetic peat can be used for soil remediation, improving soil aggregates, soil nutrients and solidifying heavy metals.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a method for preparing biomimetic peat based on high-humicity coal gangue, the preparation method comprising the following steps:

[0011] (1) Soil bacterial suspension was inoculated into lignin screening liquid culture medium for enrichment culture to obtain thermostable bacterial suspension H1;

[0012] (2) The heat-resistant bacterial solution H1 was transferred to a mixed substrate culture medium of coal gangue and garden waste, and Tween 80 was added for fermentation. After drying, the high humus coal gangue-based biomimetic peat was obtained; the fermentation time was 20 to 35 days.

[0013] Metal oxides in coal gangue are considered excellent non-biological catalysts for humification, but coal gangue alone has a low organic matter content. Therefore, the preparation method of high-humicity coal gangue-based biomimetic peat described in this invention involves forming a culture medium from coal gangue and garden waste, adding a thermoresistant bacterial solution H1 and Tween 80 for fermentation. The organic matter and metal ions in the coal gangue serve as non-biological catalysts for the synthesis of humic substances from garden waste. Tween 80 accelerates the degradation of hydrophobic organic matter, enhances microbial activity and diversity, promotes enzyme activity, and increases the yield of humic precursors such as polyphenols, polysaccharides, and amino acids, thereby increasing the humic content in the coal gangue-based biomimetic peat. This rapidly prepares high-humicity coal gangue-based biomimetic peat with advantages such as large specific surface area, high porosity, and loose, porous structure. It can be used to repair soil acidification, poor soil fertility, and poor soil aggregate structure, while simultaneously solving the problem of large-scale coal gangue accumulation and the challenge of green resource utilization of garden waste, achieving the goal of "treating waste with waste."

[0014] This invention utilizes a lignin-screening liquid culture medium to screen soil bacteria, thereby obtaining a bacterial community with excellent lignin-decomposing effects. This is because the aromatic components of humic substances originate from lignin, and polyphenols, polysaccharides, and amino acids are important precursors for humic acid formation. Therefore, the key to synthesizing high-humicity coal gangue-based biomimetic peat is to improve the degradation rate of lignin and the content of polysaccharides, polyphenols, and amino acids. This invention also screens thermophilic bacteria resistant to high temperatures from hot spring sediment, matching them with a subsequent high-temperature-mesotemperature sequential batch fermentation process, thereby achieving efficient degradation of lignin in garden waste.

[0015] The Tween 80 described in this invention is polyoxyethylene 20 sorbitan monooleate, which is a nonionic surfactant.

[0016] The fermentation time in step (2) of this invention is 20 to 35 days, for example, it can be 20 days, 23 days, 26 days, 29 days, 32 days or 35 days, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] Preferably, the soil bacteria in the soil bacterial suspension in step (1) include any one or more combinations of Bacillus spp., Bacillus thermophilus, Bacillus thermophilus, Bacillus aerobicus, Bacillus thermophilus, or Thermomycium subsp. ...

[0018] Preferably, the sodium lignin sulfonate in the lignin screening liquid culture medium is 2.0~3.5 g / L, for example, it can be 2.0 g / L, 2.3 g / L, 2.6 g / L, 2.9 g / L, 3.2 g / L or 3.5 g / L, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] The concentration of K2HPO4 is 0.5~1.5 g / L, for example, it can be 0.5 g / L, 0.7 g / L, 0.9 g / L, 1.1 g / L, 1.3 g / L or 1.5 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] The concentration of MgSO4•7H2O is 0.15~0.25 g / L, for example, it can be 0.15 g / L, 0.17 g / L, 0.19 g / L, 0.21 g / L, 0.23 g / L or 0.25 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] The CaCl2 concentration is 0.05~0.15 g / L, for example, it can be 0.05 g / L, 0.07 g / L, 0.09 g / L, 0.11 g / L, 0.13 g / L or 0.15 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0022] The FeSO4•7H2O concentration is 0.01~0.015 g / L, for example, it can be 0.01 g / L, 0.011 g / L, 0.012 g / L, 0.013 g / L, 0.014 g / L or 0.015 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] The concentration of MnSO4•H2O is 0.01~0.03 g / L, for example, it can be 0.01 g / L, 0.015 g / L, 0.02 g / L, 0.023 g / L, 0.027 g / L or 0.03 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] The concentration of KH2PO4 is 0.5~1.5 g / L, for example, it can be 0.5 g / L, 0.7 g / L, 0.9 g / L, 1.1 g / L, 1.3 g / L or 1.5 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] (NH4)2SO4 is 1.5~2.5 g / L, for example, it can be 1.5 g / L, 1.7 g / L, 1.9 g / L, 2.1 g / L, 2.3 g / L or 2.5 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the pH of the lignin screening liquid culture medium is 7.0 to 7.2, for example, it can be 7.0, 7.05, 7.08, 7.12, 7.16 or 7.2, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the enrichment culture temperature in step (1) is 50~80 ℃, for example, it can be 50 ℃, 60 ℃, 70 ℃ or 80 ℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the enrichment culture time is 0.5 to 10 days, for example, it can be 0.5 days, 1 day, 3 days, 5 days, 7 days or 10 days, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] Preferably, the mixed substrate culture medium of coal gangue and garden waste in step (2) includes NaNO3 of 2.0~3.0 g / L, for example, it can be 2.0 g / L, 2.2 g / L, 2.4 g / L, 2.6 g / L, 2.8 g / L or 3.0 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] The concentration of KH2PO4 is 0.5~1.5 g / L, for example, it can be 0.5 g / L, 0.7 g / L, 0.9 g / L, 1.1 g / L, 1.3 g / L or 1.5 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] The concentration of NaCl is 0.25~0.75 g / L, for example, it can be 0.25 g / L, 0.35 g / L, 0.45 g / L, 0.55 g / L, 0.65 g / L or 0.75 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] The concentration of MgSO4•7H2O is 0.4~0.6 g / L, for example, it can be 0.4 g / L, 0.45 g / L, 0.5 g / L, 0.53 g / L, 0.57 g / L or 0.6 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] The CaCl2 concentration is 0.05~0.15 g / L, for example, it can be 0.05 g / L, 0.07 g / L, 0.09 g / L, 0.11 g / L, 0.13 g / L or 0.15 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] The concentration of coal gangue powder is 20~40 g / L, for example, it can be 20 g / L, 25 g / L, 30 g / L, 32 g / L, 36 g / L or 40 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Garden waste powder is 5~25 g / L, for example, it can be 5 g / L, 10 g / L, 15 g / L, 18 g / L, 22 g / L or 25 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the SiO2 content in the coal gangue powder is 40% to 65% by mass percentage. For example, it can be 40%, 45%, 50%, 55%, 60%, or 65%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] The Al2O3 content is 25% to 30%, for example, it can be 25%, 26%, 27%, 28%, 29% or 30%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range also apply.

[0038] The Fe2O3 content is 5% to 10%, for example, it can be 5%, 6%, 7%, 8%, 9% or 10%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] The MgO content is 1% to 2%, for example, it can be 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] The K2O content is 4% to 5%, for example, it can be 4%, 4.2%, 4.4%, 4.6%, 4.8% or 5%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] The CaO content is 0.1% to 0.2%, for example, it can be 0.1%, 0.12%, 0.14%, 0.16%, 0.18% or 0.2%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] Preferably, the total organic matter content in the coal gangue powder is 10% to 25%, for example, it can be 10%, 12%, 15%, 20% or 25%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, the moisture content of the coal gangue powder is 0.01% to 0.1%, for example, it can be 0.01%, 0.03%, 0.05%, 0.07%, 0.09% or 0.1%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] Preferably, the pH of the coal gangue powder is 6.5 to 9.0, for example, it can be 6.5, 7.0, 7.5, 8.0, 8.5 or 9.0, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0045] Preferably, the lignin content in the garden waste powder is 40% to 45% by mass percentage, for example, it can be 40%, 41%, 42%, 43%, 44% or 45%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] The cellulose content is 20% to 25%, for example, it can be 20%, 21%, 22%, 23%, 24% or 25%, but it is not limited to the listed values. Other unlisted values ​​within this range also apply.

[0047] The hemicellulose content is 30% to 35%, for example, it can be 30%, 31%, 32%, 33%, 34% or 35%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range also apply.

[0048] Preferably, the total organic matter content in the garden waste powder is 85% to 95%, for example, it can be 85%, 87%, 89%, 91%, 93% or 95%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0049] Preferably, the moisture content of the garden waste powder is 5% to 10%, for example, it can be 5%, 6%, 7%, 8%, 9% or 10%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0050] Preferably, the pH of the garden waste powder is 5 to 6, for example, it can be 5, 5.2, 5.4, 5.6, 5.8 or 6, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0051] Preferably, the particle size of the coal gangue powder is 0.7~1 μm, for example, it can be 0.7 μm, 0.74 μm, 0.78 μm, 0.82 μm, 0.86 μm or 1 μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0052] Preferably, the particle size of the garden waste powder is 0.7~1 μm, for example, it can be 0.7 μm, 0.74 μm, 0.78 μm, 0.82 μm, 0.86 μm or 1 μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0053] Preferably, the pH of the mixed substrate culture medium of coal gangue and garden waste is 6.5 to 7.0, for example, it can be 6.5, 6.6, 6.7, 6.8, 6.9 or 7.0, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0054] Preferably, the mixed substrate culture medium of coal gangue and garden waste in step (2) also includes a mixture of trace elements.

[0055] Preferably, the volume ratio of the trace element mixture to the mixed substrate culture medium of coal gangue and garden waste is (1~5):1000, for example, it can be 1:1000, 2:1000, 3:1000, 4:1000, 4.5:1000 or 5:1000, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0056] The preferred embodiment of this invention, comprising a mixed substrate culture medium of coal gangue and garden waste, further includes a trace element mixture, which has the advantages of meeting the needs of microbial enzyme activity and maintaining microbial basal metabolism and synthesis. Adding too little of the trace element mixture can lead to slow or even stagnant microbial growth and abnormal metabolic pathways; adding too much can cause enzymes in the microorganisms to become poisoned due to excessive heavy metals.

[0057] Preferably, the FeCl2•4H2O in the trace element mixture is 1~2 g / L, for example, it can be 1 g / L, 1.2 g / L, 1.4 g / L, 1.6 g / L, 1.8 g / L or 2 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0058] The concentration of CoCl2•6H2O is 0.1~0.2 g / L, for example, it can be 0.1 g / L, 0.12 g / L, 0.14 g / L, 0.16 g / L, 0.18 g / L or 0.2 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0059] The concentration of MnCl2•2H2O is 0.05~0.1 g / L, for example, it can be 0.05 g / L, 0.06 g / L, 0.07 g / L, 0.08 g / L, 0.09 g / L or 0.1 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0060] The ZnCl2 concentration is 0.05~0.1 g / L, for example, it can be 0.05 g / L, 0.06 g / L, 0.07 g / L, 0.08 g / L, 0.09 g / L or 0.1 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0061] The concentration of H3BO3 is 0.005~0.01 g / L, for example, it can be 0.005 g / L, 0.006 g / L, 0.007 g / L, 0.008 g / L, 0.009 g / L or 0.01 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0062] The concentration of NiCl2•6H2O is 0.01~0.3 g / L, for example, it can be 0.01 g / L, 0.05 g / L, 0.1 g / L, 0.15 g / L, 0.2 g / L or 0.3 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0063] The concentration of CuCl2•2H2O is 0.01~0.3 g / L, for example, it can be 0.01 g / L, 0.05 g / L, 0.1 g / L, 0.15 g / L, 0.2 g / L or 0.3 g / L, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0064] Preferably, the trace element mixture also includes hydrochloric acid with a mass concentration of 20wt% to 25wt%, such as 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, or 25wt%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0065] Preferably, the trace element mixture of the present invention also includes hydrochloric acid with a mass concentration of 20wt%~25wt%, the role of which is to prevent the heavy metal ions in the trace element mixture from hydrolyzing and precipitating.

[0066] Preferably, the volume ratio of the hydrochloric acid to the trace element mixture is (10~15):1000, for example, it can be 10:1000, 11:1000, 12:1000, 13:1000, 14:1000 or 15:1000, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0067] Preferably, the volume fraction of Tween 80 in the mixed substrate culture medium of coal gangue and garden waste in step (2) is 0.5% to 2.5%, for example, it can be 0.5%, 0.8%, 1.2%, 1.6%, 2.0% or 2.5%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable; preferably 2%.

[0068] Preferably, the fermentation in step (2) includes high-temperature-medium-temperature sequential batch fermentation. High temperature can quickly start the reaction, rapidly obtain humic precursors, and improve humic yield. In addition, high temperature can kill pathogens, insect eggs, and weed seeds, while the mesophilic stage allows humic substances to form in large quantities, making their structure loose and eliminating odors. If only high-temperature fermentation is used, it will increase production costs. If only mesophilic fermentation is used, the fermentation start-up time is long, resulting in a long fermentation time. The temperature may not be high enough to kill pathogens, insect eggs, and weed seeds, and the degradation rate of lignin and other recalcitrant substances will be low.

[0069] Preferably, the temperature during the high-temperature fermentation stage is 60~70 ℃, for example, it can be 60 ℃, 62 ℃, 64 ℃, 66 ℃, 68 ℃ or 70 ℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0070] The stirring speed is 200~250 rpm, for example, it can be 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm or 250 rpm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0071] Preferably, the temperature during the mesophilic fermentation stage is 30~40 ℃, for example, it can be 30 ℃, 32 ℃, 34 ℃, 36 ℃, 38 ℃ or 40 ℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0072] The stirring speed is 200~250 rpm, for example, it can be 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm or 250 rpm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0073] Preferably, the fermentation time is 30 days.

[0074] Preferably, the drying in step (2) includes natural air drying or oven drying.

[0075] Preferably, the drying temperature is 35~40℃, for example, it can be 35℃, 36℃, 37℃, 38℃, 39℃ or 40℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0076] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0077] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched at 50 ℃~80 ℃ for 0.5~10 days to obtain thermostable bacterial suspension H1;

[0078] The soil bacteria in the soil bacterial suspension include any one or more combinations of Bacillus spp., Bacillus thermophilus, Thermobacterium spp., Bacillus aerobicus, Thermophilus spp., or Thermophyton floccosum; the lignin screening liquid culture medium contains 2.0–3.5 g / L sodium lignin sulfonate, 0.5–1.5 g / L K₂HPO₄, 0.15–0.25 g / L MgSO₄•7H₂O, 0.01–0.015 g / L FeSO₄•7H₂O, 0.05–0.15 g / L CaCl₂, 0.01–0.03 g / L MnSO₄•H₂O, 0.5–1.5 g / L KH₂PO₄, and 1.5–2.5 g / L (NH₄)₂SO₄; the pH of the lignin screening liquid culture medium is 7.0–7.2.

[0079] (2) The heat-resistant bacterial solution H1 was transferred to a mixed substrate culture medium of coal gangue and garden waste, and Tween 80 was added for high-temperature-medium temperature sequential batch fermentation for 20-35 days. After drying, the high humus coal gangue-based biomimetic peat was obtained.

[0080] The mixed substrate culture medium of coal gangue and garden waste includes 2.0~3.0 g / L NaNO3, 0.5~1.5 g / L KH2PO4, 0.25~0.75 g / L NaCl, 0.4~0.6 g / L MgSO4•7H2O, 0.05~0.15 g / L CaCl2, 20~40 g / L coal gangue powder, and 5~25 g / L garden waste powder.

[0081] The coal gangue powder, by mass percentage, contains 40%–65% SiO2, 25%–30% Al2O3, 5%–10% Fe2O3, 1%–2% MgO, 4%–5% K2O, and 0.1%–0.2% CaO; the total organic matter content is 10%–25%; the moisture content is 0.01%–0.1%; and the pH is 6.5–9.0. The garden waste powder, by mass percentage, contains 40%–45% lignin, 20%–25% cellulose, and 30%–35% hemicellulose; the total organic matter content is 85%–95%; the moisture content is 5%–10%; the pH is 5–6; and the particle size is 0.7–1 mm. μm; the particle size of the garden waste powder is 0.7~1 μm; the pH of the mixed substrate culture medium of coal gangue and garden waste is 6.5~7.0;

[0082] The mixed substrate culture medium of coal gangue and garden waste also includes a trace element mixture; the volume ratio of the trace element mixture to the mixed substrate culture medium of coal gangue and garden waste is (1~5):1000; the trace element mixture contains 1~2 g / L FeCl2•4H2O, 0.1~0.2 g / L CoCl2•6H2O, 0.05~0.1 g / L MnCl2•2H2O, 0.05~0.1 g / L ZnCl2, 0.005~0.01 g / L H3BO3, 0.01~0.3 g / L NiCl2•6H2O, and 0.01~0.3 g / L CuCl2•2H2O. g / L; the trace element mixture also includes hydrochloric acid with a mass concentration of 20wt%~25wt%; the volume ratio of hydrochloric acid to trace element mixture is (10~15):1000;

[0083] The volume fraction of Tween 80 in the mixed substrate culture medium of coal gangue and garden waste is 0.5%~2.5%; the temperature of the high-temperature fermentation stage is 60~70 ℃ and the stirring speed is 200~250 rpm; the temperature of the mesophilic fermentation stage is 30~40 ℃ and the stirring speed is 200~250 rpm.

[0084] The drying process includes natural air drying or drying at a temperature of 35~40℃.

[0085] Secondly, the present invention also provides a high-humic coal gangue-based biomimetic peat obtained by the high-humic coal gangue-based biomimetic peat preparation method described in the first aspect.

[0086] The biomimetic peat made from high-humicity coal gangue has a humic content of over 104.43 mg / g, a humic acid content of over 74.98 mg / g, and a fulvic acid content of over 29.44 mg / g.

[0087] Thirdly, the present invention also provides an application of high-humicity coal gangue-based biomimetic peat as described in the second aspect, wherein the high-humicity coal gangue-based biomimetic peat is used for soil remediation.

[0088] The biomimetic peat moss based on high humus coal gangue described in this invention can effectively improve soil acidification, low nutrient content, and weak aggregate structure, thus enabling soil remediation.

[0089] Preferably, the remediable soil includes any one or more combinations of ion-type rare earth tailings soil, acidified soil, or barren soil. For example, it can be a combination of ion-type rare earth tailings soil and acidified soil, a combination of barren soil and ion-type rare earth tailings soil, or a combination of acidified soil and barren soil.

[0090] Preferably, the mixing mass ratio of the high-humus coal gangue-based biomimetic peat to the remediable soil is (0.5~5):100, for example, it can be 0.5:100, 1:100, 2:100, 3:100, 4:100 or 5:100, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable; preferably, it is 1:100.

[0091] Compared with the prior art, the present invention has at least the following beneficial effects:

[0092] (1) The method for preparing biomimetic peat based on high humus coal gangue provided by the present invention uses coal gangue and garden waste as substrates, and adds thermophilic lignin-degrading bacteria and Tween 80 to improve the degradation efficiency of lignin and the content of humic acid precursor polysaccharides, polyphenols and amino acids, which greatly increases the humus content in the prepared biomimetic peat.

[0093] (2) The preparation method of high humic coal gangue-based biomimetic peat provided by the present invention helps to alleviate the problems of large-scale accumulation of coal gangue, low resource utilization rate of garden waste and peat shortage. The obtained high humic biomimetic peat can be used to improve soil acidification, low nutrient content and weak aggregate structure, and support the resource utilization of solid waste and the long-term green development of the rare earth industry. Attached Figure Description

[0094] Figure 1 The pH diagrams are for the fermentation process of Example 1 and Comparative Examples 1-2.

[0095] Figure 2 The graph shows the polyphenol concentration during the fermentation process of Example 1 and Comparative Examples 1-2.

[0096] Figure 3 The graph shows the polysaccharide concentration during the fermentation process of Example 1 and Comparative Examples 1-2.

[0097] Figure 4 The diagram shows the amino acid concentration during the fermentation process of Example 1 and Comparative Examples 1-2.

[0098] Figure 5 The graph shows the humic acid content of coal gangue-based biomimetic peat in Example 1 and Comparative Examples 1-2.

[0099] Figure 6 The graph shows the fulvic acid content of coal gangue-based biomimetic peat in Example 1 and Comparative Examples 1-2.

[0100] Figure 7 The graph shows the humic content of coal gangue-based biomimetic peat in Example 1 and Comparative Examples 1-2.

[0101] Figure 8 This is a graph showing the content of soil aggregates of different particle sizes in the soil after 40 days of culturing ryegrass seeds in Application Example 1 and Application Comparative Example 1. Detailed Implementation

[0102] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0103] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0104] The following Examples 1 and Comparative Examples 1-2 used soil bacterial suspensions consisting of a combination of *Geobacillus*, *Caldibacillus*, *Thermobacillus*, *Aeribacillus*, *Thermaerobacter*, and *Meiothermus*; Example 2 used a soil bacterial suspension consisting of *Geobacillus* and *Meiothermus*. Examples 3 and 4 use soil bacterial suspensions of a combination of *Geobacillus* and *Caldibacillus*. Comparative Examples 3 and 4 use soil bacterial suspensions of a combination of *Aeribacillus* and *Thermaerobacter*. Comparative Examples 5-8 use soil bacterial suspensions of a combination of *Meiothermus*, *Caldibacillus*, and *Aeribacillus*. The Chinese text in parentheses is a translation of the preceding Latin scientific names.

[0105] The lignin screening liquid culture medium described in the following examples and comparative examples is as follows: sodium lignin sulfonate 3.0 g, K₂HPO₄ 1.0 g, MgSO₄·7H₂O 0.2 g, CaCl₂ 0.1 g, FeSO₄·7H₂O 0.05 g, MnSO₄·H₂O 0.02 g, KH₂PO₄ 1.0 g, (NH₄)₂SO₄ 2.0 g, pH 7.0, diluted with water to a final volume of 1 L. The pH of the lignin screening liquid culture medium is 7.0.

[0106] The mixed substrate culture medium of coal gangue and garden waste described in the following examples and comparative examples is as follows: NaNO3 2.5g, KH2PO4 1.0g, NaCl 0.5g, MgSO4·7H2O 0.5g, CaCl2 0.1g, trace element mixture 1mL, coal gangue powder 30g, osmanthus branch and leaf powder 10g, pH 6.5, and water added to a final volume of 1L. The garden waste consists of dried osmanthus branches and leaves, crushed and passed through a 200-mesh sieve; the coal gangue is crushed and passed through a 200-mesh sieve. Trace element mixture: 12.5 mL of 20% hydrochloric acid (w / w), 1.5 g of FeCl2·4H2O, 0.19 g of CoCl2·6H2O, 0.082 g of MnCl2·2H2O, 0.07 g of ZnCl2, 0.006 g of H3BO3, 0.024 g of NiCl2·6H2O, and 0.02 g of CuCl2·2H2O, diluted with water to 1 L.

[0107] The properties of the coal gangue powder described in the following examples and comparative examples are shown in Table 1.

[0108]

[0109] The properties of the garden waste powder described in the following examples and comparative examples are shown in Table 2.

[0110]

[0111] The pH of the mixed substrate culture medium of coal gangue and garden waste described in the following examples and comparative examples is 6.5.

[0112] The coal gangue liquid culture medium described in Comparative Examples 3 and 4 consisted of 2.5 g NaNO3, 1.0 g KH2PO4, 0.5 g NaCl, 0.5 g MgSO4•7H2O, 0.1 g CaCl2, 1 mL of trace element mixture, 60 g coal gangue powder, and a pH of 6.5, with water added to a final volume of 1 L.

[0113] Comparative Examples 5 and 6: Liquid culture medium made from garden waste using Osmanthus twig powder: 2.5g NaNO3, 1.0g KH2PO4, 0.5g NaCl, 0.5g MgSO4·7H2O, 0.1g CaCl2, 1mL trace element mixture, 20g Osmanthus twig and leaf powder, pH 6.5, diluted to 1L with water.

[0114] Example 1

[0115] This embodiment provides a method for preparing biomimetic peat based on high humus coal gangue, the preparation method comprising the following steps:

[0116] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 1 day to obtain thermostable bacterial suspension H1;

[0117] (2) The heat-resistant bacterial solution H1 was inoculated into a mixed substrate culture medium of coal gangue and garden waste at an inoculation amount of 10% (v / v), and Tween 80 was added to carry out high-temperature-medium temperature sequential batch fermentation in a water bath shaker. After drying, the high humus coal gangue-based biomimetic peat was obtained.

[0118] The volume fraction of Tween 80 in the mixed substrate culture medium of coal gangue and garden waste is 2%; the temperature of the high-temperature fermentation stage is 60 ℃, the stirring speed is 200 rpm, and the fermentation is carried out for 15 days; the temperature of the mesophilic fermentation stage is 30 ℃, the stirring speed is 200 rpm, and the fermentation is carried out for 15 days; the drying is natural air drying.

[0119] Example 2

[0120] This embodiment provides a method for preparing biomimetic peat based on high humus coal gangue, the preparation method comprising the following steps:

[0121] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 1 day to obtain thermostable bacterial suspension H1;

[0122] (2) The heat-resistant bacterial solution H1 was inoculated into a mixed substrate culture medium of coal gangue and garden waste at an inoculation rate of 5% (v / v), and Tween 80 was added to carry out high-temperature-medium temperature sequential batch fermentation in a water bath shaker. After drying, the high humus coal gangue-based biomimetic peat was obtained.

[0123] The volume fraction of Tween 80 in the mixed substrate culture medium of coal gangue and garden waste is 1%; the temperature of the high-temperature fermentation stage is 60 ℃, the stirring speed is 200 rpm, and the fermentation is carried out for 12 days; the temperature of the mesophilic fermentation stage is 30 ℃, the stirring speed is 200 rpm, and the fermentation is carried out for 12 days; the drying is an oven drying at a temperature of 40 ℃.

[0124] Example 3

[0125] This embodiment provides a method for preparing biomimetic peat based on high humus coal gangue, the preparation method comprising the following steps:

[0126] This embodiment provides a method for preparing biomimetic peat based on high humus coal gangue, the preparation method comprising the following steps:

[0127] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 1 day to obtain thermostable bacterial suspension H1;

[0128] (2) The heat-resistant bacterial solution H1 was inoculated into a mixed substrate culture medium of coal gangue and garden waste at an inoculation amount of 15% (v / v), and Tween 80 was added to carry out high-temperature-medium temperature sequential batch fermentation in a water bath shaker. After drying, the high humus coal gangue-based biomimetic peat was obtained.

[0129] The volume fraction of Tween 80 in the mixed substrate culture medium of coal gangue and garden waste is 2.5%; the temperature of the high-temperature fermentation stage is 60 ℃, the stirring speed is 200 rpm, and the fermentation is carried out for 12 days; the temperature of the mesophilic fermentation stage is 30 ℃, the stirring speed is 200 rpm, and the fermentation is carried out for 12 days; the drying is an oven drying at a temperature of 40 ℃.

[0130] Comparative Example 1

[0131] This comparative example provides a method for preparing coal gangue-based biomimetic peat, the method comprising the following steps:

[0132] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 1 day to obtain thermostable bacterial suspension H1;

[0133] (2) The heat-resistant bacterial solution H1 was inoculated into a mixed substrate culture medium of coal gangue and garden waste at an inoculation rate of 10% (v / v), and high-temperature-medium temperature sequential batch fermentation was carried out in a water bath shaker. After drying, the coal gangue-based biomimetic peat was obtained.

[0134] The high-temperature fermentation stage is carried out at a temperature of 60 ℃ and a stirring speed of 200 rpm for 15 days; the medium-temperature fermentation stage is carried out at a temperature of 30 ℃ and a stirring speed of 200 rpm for 15 days; the drying is carried out by natural air drying.

[0135] Comparative Example 2

[0136] This comparative example provides a method for preparing coal gangue-based biomimetic peat, the method comprising the following steps:

[0137] Coal gangue and garden waste were mixed as substrate culture medium and subjected to high-temperature-medium-temperature sequential batch fermentation in a water bath shaker. After drying, the coal gangue-based biomimetic peat was obtained.

[0138] The high-temperature fermentation stage is carried out at a temperature of 60 ℃ and a stirring speed of 200 rpm for 15 days; the medium-temperature fermentation stage is carried out at a temperature of 30 ℃ and a stirring speed of 200 rpm for 15 days; the drying is carried out by natural air drying.

[0139] Figure 1 The pH diagrams are for the fermentation process of Example 1 and Comparative Examples 1-2. Figure 2 The graph shows the polyphenol concentration during the fermentation process of Example 1 and Comparative Examples 1-2. Figure 3 The graph shows the polysaccharide concentration during the fermentation process of Example 1 and Comparative Examples 1-2. Figure 4 The diagram shows the amino acid concentration during the fermentation process of Example 1 and Comparative Examples 1-2. Figures 1-4 In the text, TW represents Example 1, BW represents Comparative Example 1, and CK represents Comparative Example 2.

[0140] from Figures 1-4It can be seen that Comparative Example 2 exhibited a large pH fluctuation during fermentation, becoming more alkaline in the later stages. Example 1, with the addition of Tween 80, showed a smaller pH fluctuation during fermentation, remaining near neutral after fermentation. During fermentation, the polyphenol content of Examples 1 and Comparative Examples 1-2 decreased over time, with Example 1 consistently showing a higher polyphenol content than Comparative Examples 1-2. The polysaccharide content in Examples 1 and Comparative Example 1 initially increased and then decreased over time, while the polysaccharide content in Comparative Example 2 decreased over time, with Example 1 showing a higher polysaccharide content than Comparative Examples 1-2 in the later stages. The amino acid content in Example 1 increased over time, while in Comparative Example 1 it initially decreased and then increased, and in Comparative Example 2 it initially increased and then decreased, with Example 1 showing a higher amino acid content than Comparative Example 1 and not significantly different from Comparative Example 2 in the later stages.

[0141] Figure 5 The graph shows the humic acid (HA) content of coal gangue-based biomimetic peat in Example 1 and Comparative Examples 1-2. Figure 6 The graph shows the fulvic acid (FA) content of coal gangue-based biomimetic peat in Example 1 and Comparative Examples 1-2. Figure 7 The graph shows the humic (HS) content of coal gangue-based biomimetic peat in Example 1 and Comparative Examples 1-2. Figures 5-7 In the text, TW represents Example 1, BW represents Comparative Example 1, and CK represents Comparative Example 2.

[0142] from Figures 5-7 It can be seen that the humic substance (HS) content in Example 1 reached 104.43 mg / g, which is much higher than that of Comparative Example 1 (62.37 mg / g) and Comparative Example 2 (56.62 mg / g). The humic acid (HA) content in Example 1 was 74.98 mg / g, which is higher than that of Comparative Example 1 (20.49 mg / g) and Comparative Example 2 (24.26 mg / g), respectively. The fulvic acid (FA) content in Example 1 was 29.44 mg / g, which is 4 times and 5 times that of Comparative Example 1 and Comparative Example 2, respectively. Therefore, the addition of Tween 80 can significantly increase the content of various components of humic substance.

[0143] Comparative Example 3

[0144] This comparative example provides a method for preparing coal gangue-based biomimetic peat, the method comprising the following steps:

[0145] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 7 days to obtain thermostable bacterial suspension H1;

[0146] (2) The heat-resistant bacterial solution H1 was inoculated into the coal gangue liquid culture medium at an inoculation amount of 10% (v / v), and Tween 80 was added to carry out high-temperature-medium temperature sequential batch fermentation in a water bath shaker. After drying, the coal gangue-based biomimetic peat was obtained.

[0147] The volume fraction of Tween 80 in the coal gangue liquid culture medium is 2.5%; the temperature of the high-temperature fermentation stage is 60℃, the stirring speed is 200 rpm, and the fermentation is carried out for 10 days; the temperature of the mesophilic fermentation stage is 30℃, the stirring speed is 200 rpm, and the fermentation is carried out for 10 days; the drying is carried out at 35℃.

[0148] Comparative Example 4

[0149] This comparative example provides a method for preparing coal gangue-based biomimetic peat, the method comprising the following steps:

[0150] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 7 days to obtain thermostable bacterial suspension H1;

[0151] (2) The heat-resistant bacterial solution H1 was inoculated into the coal gangue liquid culture medium at an inoculation amount of 10% (v / v), and high-temperature-medium temperature sequential batch fermentation was carried out in a water bath shaker. After drying, the coal gangue-based biomimetic peat was obtained.

[0152] The high-temperature fermentation stage is carried out at a temperature of 60 ℃ and a stirring speed of 200 rpm for 10 days; the medium-temperature fermentation stage is carried out at a temperature of 30 ℃ and a stirring speed of 200 rpm for 10 days; the drying stage is carried out at 35 ℃.

[0153] Comparative Example 5

[0154] This comparative example provides a method for preparing coal gangue-based biomimetic peat, the method comprising the following steps:

[0155] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 7 days to obtain thermostable bacterial suspension H1;

[0156] (2) The heat-resistant bacterial solution H1 was inoculated into the garden waste liquid culture medium at an inoculation amount of 10% (v / v), and Tween 80 was added. The mixture was then subjected to high-temperature-medium-temperature sequential batch fermentation in a water bath shaker. After drying, the coal gangue-based biomimetic peat was obtained.

[0157] The liquid culture medium containing garden waste contains 2.5% Tween 80 by volume; the high-temperature fermentation stage is carried out at 60 ℃ with a stirring speed of 200 rpm for 10 days; the medium-temperature fermentation stage is carried out at 30 ℃ with a stirring speed of 200 rpm for 10 days; and the drying process is carried out at 35 ℃.

[0158] Comparative Example 6

[0159] This comparative example provides a method for preparing coal gangue-based biomimetic peat, the method comprising the following steps:

[0160] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 7 days to obtain thermostable bacterial suspension H1;

[0161] (2) The heat-resistant bacterial solution H1 was inoculated into the garden waste liquid culture medium at an inoculation rate of 10% (v / v), and high-temperature-medium temperature sequential batch fermentation was carried out in a water bath shaker. After drying, the coal gangue-based biomimetic peat was obtained.

[0162] The high-temperature fermentation stage is carried out at a temperature of 60 ℃ and a stirring speed of 200 rpm for 10 days; the medium-temperature fermentation stage is carried out at a temperature of 30 ℃ and a stirring speed of 200 rpm for 10 days; the drying stage is carried out at 35 ℃.

[0163] Comparative Example 7

[0164] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 7 days to obtain thermostable bacterial suspension H1;

[0165] (2) The heat-resistant bacterial solution H1 was inoculated into a mixed substrate culture medium of coal gangue and garden waste at an inoculation rate of 10% (v / v), and Tween 80 was added to carry out high-temperature-medium temperature sequential batch fermentation in a water bath shaker. After drying, the coal gangue-based biomimetic peat was obtained.

[0166] The volume fraction of Tween 80 in the mixed substrate culture medium of coal gangue and garden waste is 2%; the temperature of the high-temperature fermentation stage is 60 ℃, the stirring speed is 200 rpm, and the fermentation is carried out for 10 days; the temperature of the mesophilic fermentation stage is 30 ℃, the stirring speed is 200 rpm, and the fermentation is carried out for 10 days; the drying is carried out at 45 ℃.

[0167] Comparative Example 8

[0168] (1) Soil bacterial suspension was inoculated into lignin screening liquid medium and enriched in a water bath shaker at 60 °C for 7 days to obtain thermostable bacterial suspension H1;

[0169] (2) The heat-resistant bacterial solution H1 was inoculated into a mixed substrate culture medium of coal gangue and garden waste at an inoculation rate of 10% (v / v), and high-temperature-medium temperature sequential batch fermentation was carried out in a water bath shaker. After drying, the coal gangue-based biomimetic peat was obtained.

[0170] The high-temperature fermentation stage is carried out at a temperature of 60 ℃ and a stirring speed of 200 rpm for 10 days; the medium-temperature fermentation stage is carried out at a temperature of 30 ℃ and a stirring speed of 200 rpm for 10 days; the drying stage is carried out at 45 ℃.

[0171] The results of the humic component content in the coal gangue-based biomimetic peat of Examples 1-3 and Comparative Examples 3-8 are shown in Table 3.

[0172]

[0173] Table 3 shows that the contents of humic substances (104.43 mg / g), humic acid (74.98 mg / g), and fulvic acid (29.44 mg / g) in Example 1 are all higher than those in Examples 2-3 and Comparative Examples 3-8, indicating that Example 1 represents the optimal conditions for synthesizing biomimetic peat based on coal gangue.

[0174] Application Example 1

[0175] This application example provides a method for applying the high-humicity coal gangue-based biomimetic peat described in Example 1, wherein the high-humicity coal gangue-based biomimetic peat is used to remediate ion-adsorption rare earth tailings soil.

[0176] The soil samples were collected from the tailings area of ​​a certain county. After collection, the soil was placed in a cool and ventilated place to air dry naturally. After removing plant roots, stones and debris, the soil was passed through a 10-mesh nylon sieve for later use.

[0177] 1% (w / w) of coal gangue-based biomimetic peat (PT) from Example 1 was added to pots containing 500g of the test soil. The soil moisture content was maintained at 70% of its maximum water holding capacity (dry weight). After the coal gangue-based biomimetic peat was evenly mixed with the soil, 16 ryegrass seeds were added to each pot, placed approximately 1cm below the topsoil. The pots were then placed in an artificial climate chamber for cultivation. The climate chamber was set to 14 hours of daytime at 25°C and 10 hours of nighttime at 20°C, with 70% humidity. Each treatment group had three replicates. Ryegrass was harvested after 40 days of cultivation.

[0178] Application Comparative Example 1

[0179] Except for the absence of the high-humicity coal gangue-based biomimetic peat described in Example 1, the other processing steps in this comparative application are the same as in Application Example 1.

[0180] Table 4 shows the soil indices tested and the soil indices after culturing ryegrass seeds for 40 days in Application Example 1 and Application Comparative Example 1.

[0181]

[0182] Table 4 shows that the soil pH value increased from 5.77 to 6.25 with the addition of coal gangue-based biomimetic peat, while the pH value of the control group remained almost unchanged. The organic matter content also increased significantly to 6.38 mg / kg, while the organic matter content of the soil without coal gangue-based biomimetic peat decreased due to the planting of ryegrass. The available nitrogen (AN), available potassium (AK), and available phosphorus (AP) levels were higher in the soil than in the tested soil and the control group. Therefore, it can be concluded that the synthesized coal gangue-based biomimetic peat can increase the pH value of the tested soil, alleviate soil acidification, increase soil nutrients, and solve the problem of soil nutrient deficiency.

[0183] The content of soil aggregates of different particle size ranges in the soil after 40 days of ryegrass seed cultivation in Application Example 1 and Comparative Application Example 1 is as follows: Figure 8 As shown. Figure 8 In this context, CK represents Application Comparison 1, and PT represents Application Example 1. From... Figure 8 It can be seen that in soils with added coal gangue-based biomimetic peat, the proportion of soil aggregates >2mm is 8.45%, soil aggregates of 2-1mm are 22.11%, soil aggregates of 1-0.25mm are 47.17%, and soil aggregates <0.25mm are 21.26%; in soils without added coal gangue-based biomimetic peat, the proportions are 6.35%, soil aggregates of 2-1mm are 17.46%, soil aggregates of 1-0.25mm are 47.15%, and soil aggregates <0.25mm are 28.59%. Therefore, the synthesized coal gangue-based biomimetic peat can increase the proportion of large soil aggregates and decrease the proportion of soil aggregates <0.25mm.

[0184] Application Example 1 uses the high-humus coal gangue-based biomimetic peat prepared in Example 1 to remediate ion-adsorption rare earth tailings soil. After culturing ryegrass seeds in this mixed soil for 40 days, the survival rate of ryegrass was 94.28%.

[0185] In Comparative Example 1, without the addition of high-humus coal gangue-based biomimetic peat, ryegrass seeds were added to ion-type rare earth tailings soil and cultured for 40 days. The survival rate of ryegrass was only 77.49%, which proves that the high-humus coal gangue-based biomimetic peat prepared by this invention has a good soil remediation effect.

[0186] It should be noted that the above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing biomimetic peat based on high-humicity coal gangue, characterized in that, The preparation method includes the following steps: (1) Soil bacterial suspension was inoculated into lignin screening liquid culture medium for enrichment culture to obtain thermostable bacterial suspension H1; (2) The heat-resistant bacterial solution H1 was transferred to a mixed substrate culture medium of coal gangue and garden waste, and Tween 80 was added for fermentation. After drying, the high humus coal gangue-based biomimetic peat was obtained; the fermentation time was 20 to 35 days.

2. The preparation method according to claim 1, characterized in that, The soil bacteria in the soil bacterial suspension in step (1) include any one or more combinations of Bacillus terrestris, Bacillus thermophilus, Bacillus thermobacter, Bacillus aerobicus, Bacillus thermophilus, or Thermomycium subterraneanum. Preferably, the lignin screening liquid culture medium contains 2.0~3.5 g / L sodium lignin sulfonate, 0.5~1.5 g / L K2HPO4, 0.15~0.25 g / L MgSO4•7H2O, 0.01~0.015 g / L FeSO4•7H2O, 0.05~0.15 g / L CaCl2, 0.01~0.03 g / L MnSO4•H2O, 0.5~1.5 g / L KH2PO4, and 1.5~2.5 g / L (NH4)2SO4. Preferably, the pH of the lignin screening liquid culture medium is 7.0 to 7.

2.

3. The preparation method according to claim 1 or 2, characterized in that, The enrichment culture temperature in step (1) is 50℃~80℃; Preferably, the enrichment culture time is 0.5 to 10 days.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The mixed substrate culture medium of coal gangue and garden waste in step (2) includes 2.0~3.0 g / L NaNO3, 0.5~1.5 g / L KH2PO4, 0.25~0.75 g / L NaCl, 0.4~0.6 g / L MgSO4•7H2O, 0.05~0.15 g / L CaCl2, 20~40 g / L coal gangue powder, and 5~25 g / L garden waste powder; Preferably, by mass percentage, the coal gangue powder contains 40%~65% SiO2, 25%~30% Al2O3, 5%~10% Fe2O3, 1%~2% MgO, 4%~5% K2O, and 0.1%~0.2% CaO; Preferably, the total organic matter content in the coal gangue powder is 10% to 25%; Preferably, the moisture content of the coal gangue powder is 0.01%~0.1%; Preferably, the pH of the coal gangue powder is 6.5~9.0; Preferably, the garden waste powder contains 40%~45% lignin, 20%~25% cellulose, and 30%~35% hemicellulose by weight percentage; Preferably, the total organic matter content in the garden waste powder is 85%~95%; Preferably, the moisture content of the garden waste powder is 5% to 10%; Preferably, the pH of the garden waste powder is 5-6; Preferably, the particle size of the coal gangue powder is 0.7~1 μm; Preferably, the particle size of the garden waste powder is 0.7~1 μm; Preferably, the pH of the mixed substrate culture medium of coal gangue and garden waste is 6.5 to 7.

0.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The mixed substrate culture medium of coal gangue and garden waste in step (2) also includes a trace element mixture; Preferably, the volume ratio of the trace element mixture to the mixed substrate culture medium of coal gangue and garden waste is (1~5): 1000; Preferably, the trace element mixture contains 1-2 g / L FeCl2•4H2O, 0.1-0.2 g / L CoCl2•6H2O, 0.05-0.1 g / L MnCl2•2H2O, 0.05-0.1 g / L ZnCl2, 0.005-0.01 g / L H3BO3, 0.01-0.3 g / L NiCl2•6H2O, and 0.01-0.3 g / L CuCl2•2H2O. Preferably, the trace element mixture further includes hydrochloric acid with a mass concentration of 20wt% to 25wt%; Preferably, the volume ratio of the hydrochloric acid to the trace element mixture is (10~15):1000.

6. The preparation method according to any one of claims 1 to 5, characterized in that, In step (2), the volume fraction of Tween 80 in the mixed substrate culture medium of coal gangue and garden waste is 0.5% to 2.5%, preferably 2%.

7. The preparation method according to any one of claims 1 to 6, characterized in that, The fermentation described in step (2) includes high-temperature-medium-temperature sequential batch fermentation; Preferably, the temperature during the high-temperature fermentation stage is 60~70 ℃, and the stirring speed is 200~250 rpm; Preferably, the temperature during the mesophilic fermentation stage is 30-40 °C, and the stirring speed is 200-250 rpm; Preferably, the fermentation time is 30 days; Preferably, the drying includes natural air drying or oven drying; Preferably, the drying temperature is 35~40℃.

8. A high-humic coal gangue-based biomimetic peat obtained by the preparation method of high-humic coal gangue-based biomimetic peat according to any one of claims 1 to 7.

9. An application of the high-humicity coal gangue-based biomimetic peat as described in claim 8, characterized in that, The high-humus coal gangue-based biomimetic peat is used for soil remediation.

10. The application according to claim 9, characterized in that, Remediable soils include any combination of at least two of the following: ion-type rare earth tailings soils, acidified soils, or impoverished soils. Preferably, the mixing mass ratio of the high humus coal gangue-based biomimetic peat to the remediable soil is (0.5~5):100, more preferably 1:100.

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