Porous supports, methods for their preparation and use

Abstract

The application relates to the technical field of solid waste resource utilization, and discloses a porous carrier and a preparation method and application thereof. The porous carrier is prepared by the following steps: mixing gneiss stone powder, biological organic matter and an inorganic binder to perform granulation treatment, to obtain composite particles; and performing pyrolysis activation treatment on the composite particles to obtain the porous carrier; wherein, according to the mass percentage of the composite particles, the gneiss stone powder accounts for 60-90%, the biological organic matter accounts for 8-35%, and the inorganic binder accounts for 2-8%. The porous carrier prepared by the method can realize effective microbial loading and better soil improvement effect.

Description

Technical Field

[0001] This application relates to the interdisciplinary technical field of solid waste resource utilization and soil remediation materials, specifically to porous carriers, their preparation methods, and applications. Background Technology

[0002] With the rapid development of infrastructure construction, urbanization, and water conservancy and hydropower projects worldwide, large-scale construction sand and gravel aggregates are required. However, the over-exploitation of natural sand and gravel has led to serious ecological problems such as resource depletion. In related fields, manufactured sand and gravel are often produced by mechanically crushing parent rocks (such as granite and gneiss), and manufactured sand and gravel have become the main source of construction sand and gravel aggregates. However, in the processing of manufactured sand and gravel, to remove ultrafine particles (particle size <0.075mm) that do not meet construction standards from the finished aggregate, a water washing process is usually used. These washed-off ultrafine particles mix with water to form slurry, which, after sedimentation, concentration, and dehydration, becomes stone powder cake, also known as waste stone powder. The output of this type of waste stone powder is staggering, typically accounting for 10% to 25% of the original ore mining output. If this waste stone powder is dumped indiscriminately, it not only occupies a large amount of land resources but also easily causes dust pollution, soil erosion, and potential heavy metal leaching risks under the influence of wind and rain, posing a serious threat to the regional ecological environment.

[0003] The main component of stone powder mud cake, gneiss, is a widely distributed metamorphic rock, primarily composed of minerals such as feldspar, quartz, and biotite. Its main framework consists of silicon dioxide (SiO2) and aluminum oxide (Al2O3), and it is rich in potassium (K2O, content reaching 3%–5%), calcium (CaO), magnesium (MgO), iron (Fe2O3), and other essential nutrients for plant growth. Therefore, gneiss powder in stone powder mud cake has the potential to be used as a mineral fertilizer or soil conditioner. Meanwhile, the demand for functional materials in the environmental remediation field is rapidly increasing. Particularly in agriculture, the extensive use of traditional chemical fertilizers has led to a series of problems such as soil compaction, acidification, nutrient leaching loss, and non-point source pollution, requiring improvement through soil composition adjustment and microbial cultivation.

[0004] However, gneiss, as a mineral, possesses a dense physical structure and stable mineral composition. The nutrients contained within its mineral composition are firmly bound within the silicate crystal lattice, existing in a sparingly soluble or slowly soluble state. Therefore, the dissolution and release rate of mineral nutrients from gneiss under natural conditions is extremely slow, far from meeting the nutrient requirements of crops throughout their growth cycle. If unmodified gneiss powder is directly used as topsoil or applied to farmland, its fertilizing effect is negligible, failing to achieve efficient utilization of this resource.

[0005] Therefore, there is an urgent need for a low-cost, high-efficiency technology to transform the vast reserves of inert gneiss powder into a composite material with controllable structure and slow-release properties, thereby improving the nutrient utilization efficiency of gneiss and reducing the environmental burden caused by its accumulation as waste. This project has significant economic, social, and ecological value. It should be noted that the above statements are only for providing background information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0006] In a first aspect of this application, a method for preparing a porous carrier is proposed, comprising: mixing and granulating gneiss powder, biological organic matter, and an inorganic binder to obtain composite particles; and subjecting the composite particles to pyrolysis activation treatment to obtain the porous carrier; wherein, based on the mass of the composite particles, the mass percentages are: gneiss powder 60%~90%, biological organic matter 8%~35%, and inorganic binder 2%~8%.

[0007] In some embodiments, the temperature of the pyrolysis activation treatment is 400°C to 650°C; and / or, the heating rate of the pyrolysis activation treatment is 5°C / min to 20°C / min.

[0008] In some embodiments, the Dv50 particle size of the gneiss powder is 50 μm to 150 μm; and / or, the inorganic binder includes at least one of bentonite, kaolinite, or attapulgite.

[0009] In some embodiments, at least one of the following conditions is met: the Dv50 particle size of the biological organic matter is 150 μm to 250 μm; the water content of the biological organic matter is less than or equal to 10%; the biological organic matter includes at least one of agricultural waste, wood processing waste, garden waste, and municipal sludge.

[0010] In some embodiments, the composite particles further include at least one of a flux and a supplement, wherein the amount of flux added is 1% to 3%, and the flux includes at least one of low melting point glass powder and water glass; the amount of supplement added is 1% to 3%, and the supplement includes at least one of phosphate rock powder, dolomite powder, and ferrous sulfate.

[0011] In a second aspect, this application proposes a porous carrier prepared using the method proposed in this application, comprising: biomass carbon; a mineral matrix dispersed in the biomass carbon, wherein the porous carrier has a specific surface area of ​​80 m². 2 / g~150m 2 / g.

[0012] In some embodiments, the total pore volume of the porous carrier is 0.15 cm³. 3 / g~0.30cm 3 / g.

[0013] In a third aspect of this application, a composite sustained-release material is proposed, comprising a carrier and microorganisms loaded on the carrier; the carrier comprises the porous carrier proposed in this application, or a porous carrier prepared by the method proposed in this application.

[0014] In some embodiments, the effective viable count of the microorganisms is greater than or equal to 10. 8 CFU / g.

[0015] In some embodiments, the microorganisms include one or more of potassium-solubilizing bacteria, nitrogen-fixing bacteria, and phosphate-solubilizing bacteria that participate in nutrient metabolism; and / or one or more of Pseudomonas, Bacillus, and Neosphingolipids that degrade pollutants.

[0016] The beneficial effects of the technical solution proposed in this application include at least the following: This application provides a low-cost technical means for utilizing gneiss in waste materials such as stone powder and mud cake, including a porous carrier and its preparation method. The porous carrier prepared from gneiss using the method of this application has good mechanical strength and water resistance, and exhibits high stability in soil. Therefore, the porous carrier of this application can be used as a slow-release source of mineral nutrients for soil improvement, and also as an immobilization carrier for microorganisms, providing an innovative, efficient, economical, and environmentally friendly solution for ecological environment restoration. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the particle structure of a porous carrier loaded with microorganisms prepared in one embodiment of this application; Figure 2 This is a scanning electron microscope (SEM) image of the gneiss powder used in Example 1 of this application. Figure 3 The apparent morphology of the porous carrier prepared in Example 1 of this application; Figure 4 This is a SEM image of the porous carrier prepared in Example 1 of this application.

[0018] Explanation of reference numerals in the attached figures: 21. Mineral matrix, 22. Biomass carbon, 23. Microorganisms. Detailed Implementation

[0019] The embodiments of this application are described in detail below, with examples of these embodiments shown in the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0020] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this application; unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0021] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are open-ended expressions, meaning they include what is specified in this application but do not exclude other aspects.

[0022] In the description of this application, all figures disclosed herein, whether or not the words "approximately" or "about" are used, are approximate values. Each figure may vary by less than 10% or by a difference that is considered reasonable by one of the art, such as 1%, 2%, 3%, 4%, or 5%.

[0023] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0024] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0025] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0026] This application provides a novel, low-cost technique for utilizing gneiss from waste materials such as stone powder and mud cake, including a porous carrier and its preparation method. This porous carrier can serve as both a slow-release source of mineral nutrients and an immobilization carrier for microorganisms, providing an innovative, efficient, economical, and environmentally friendly solution for ecological restoration.

[0027] In a first aspect of this application, a method for preparing a porous carrier is proposed, comprising: mixing and granulating gneiss powder, biological organic matter, and an inorganic binder to obtain composite particles; and subjecting the composite particles to pyrolysis activation treatment to obtain the porous carrier; wherein, based on the mass of the composite particles, the mass percentages are: gneiss powder 60%~90%, biological organic matter 8%~35%, and inorganic binder 2%~8%.

[0028] The method proposed in this application is referenced. Figure 2Composite particles of various shapes can be prepared by mixing and granulating gneiss powder, which has a flaky or blocky structure, a dense structure without obvious pores, with bio-organic matter. These composite particles can be prepared into cylindrical, spherical, or other shapes depending on the application. The bio-organic matter can be sourced locally, selecting organic waste rich in biomass, such as rice husks, corn stalks, sawdust, garden waste, and municipal sludge. Inorganic binders can improve the mechanical strength of the prepared composite particles and facilitate low-temperature sintering during pyrolysis activation. The composite particles undergo pyrolysis activation treatment, during which the bio-organic matter decomposes and vaporizes upon heating. Biomolecules such as lignin, which are difficult to decompose in bio-organic matter, are converted into biomass carbon. Smaller biomass molecules undergo pyrolysis under anaerobic conditions, producing small-molecule gases (CO, H2, CH4, etc.) and liquids (bio-oil, etc.). The escape of these products leaves micron-sized macropores and mesopores within the formed biomass carbon, thus creating a rich porous structure in situ after pyrolysis activation. During pyrolysis activation, the mineral crystal structure of gneiss powder is disrupted, forming a mineral matrix organically combined with biomass carbon. The reducing gases (such as CO and H2) produced by the pyrolysis of bio-organic matter create a pyrolysis atmosphere that reduces some high-valence metal oxides (such as Fe2O3) in the gneiss, generating more reactive low-valence oxides (such as Fe3O4). This further improves the surface chemistry and catalytic activity of the material, significantly increasing the bioavailability of trace elements such as potassium, silicon, calcium, and magnesium. After pyrolysis activation, the product is naturally or forcibly cooled to room temperature under the protection of an inert gas (such as N2). refer to Figure 3 and Figure 4 A porous carrier comprising an interconnected porous carbon framework and a gneiss mineral matrix was prepared. This porous carrier is grayish-black or black, hard, porous, and lightweight. Consequently, this mineral material has a high specific surface area and pore volume.

[0029] In some embodiments, the gneiss rock powder is pre-screened before mixing and granulation. This removes large particles and impurities from the gneiss rock powder.

[0030] In some embodiments, the gneiss powder is dried. For example, it is dried in an oven at 100°C to 110°C until constant weight (moisture content less than 1%), and then ground using a ball mill. This controls the particle size distribution of the gneiss powder, and a finer particle size is beneficial for preparing denser composite particles in the subsequent mixing and granulation process and for improving the uniformity of the pyrolysis activation treatment.

[0031] In some embodiments, the biological organic matter is pulverized before the mixing and granulation process, such as by sieving through a 60-100 mesh sieve.

[0032] In some embodiments, the temperature of the pyrolysis activation treatment is 400℃~650℃; and / or, the heating rate of the pyrolysis activation treatment is 5℃ / min~20℃ / min. Under the aforementioned pyrolysis activation conditions, although the feldspar, mica, and other silicate minerals in the gneiss do not reach their melting point, their crystal structure will develop microcracks and lattice defects due to thermal stress, and the bond energy of some chemical bonds (such as Si-O-Al, KO-Si) will be weakened or broken. The aforementioned changes activate the chemical activity of elements such as potassium, calcium, and magnesium, which were originally bound in a stable lattice, significantly improving their dissolution rate and bioavailability in water. Furthermore, the biological organic matter undergoes in-situ carbonization at this temperature, and the biomass macromolecules assist in the formation of a porous structure, fully coating the mineral matrix formed after the pyrolysis activation of the gneiss. This improves the slow-release capacity of nutrients in the prepared porous carrier.

[0033] In some embodiments, the Dv50 particle size of the gneiss powder is 50 μm to 150 μm; and / or, the inorganic binder includes at least one of bentonite, kaolinite, or attapulgite. The aforementioned inorganic binder possesses good adsorption and cation exchange capacity, thereby improving the porous carrier's ability to adsorb, migrate, and transform substances or microorganisms in the environment.

[0034] As an example, the Dv50 particle size of the gneiss powder is 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm or 150μm.

[0035] In some embodiments, at least one of the following conditions is met: the Dv50 particle size of the bio-organic matter is 150 μm to 250 μm; the water content of the bio-organic matter is less than or equal to 10%; the bio-organic matter includes at least one of agricultural waste, wood processing waste, garden waste, and municipal sludge. The aforementioned bio-organic matter is widely available and inexpensive, and its utilization can effectively recycle some organic wastes (such as agricultural and forestry waste, and domestic solid waste) from daily life and production. The fact that the particle size and water content of the bio-organic matter meet the aforementioned ranges facilitates thorough mixing of different components when co-treated with gneiss powder, and allows for more uniform heating and synergistic changes during pyrolysis activation treatment. This is beneficial for preparing porous carriers with consistent product structure and stable performance.

[0036] In some embodiments, the method further includes: pre-drying the composite particles before the pyrolysis activation treatment, wherein the pre-drying temperature is 60℃~95℃. Pre-drying can reduce the moisture content of the composite particles to 5% or less. Lower moisture content helps reduce the amount of water vapor generated during the pyrolysis activation treatment due to temperature rise in the pyrolysis furnace. This helps reduce problems such as particle bursting caused by rapid particle expansion during the pyrolysis activation treatment.

[0037] In some embodiments, the composite particles further include at least one of a flux and a supplement, wherein the flux is added at an amount of 1% to 3%, and the flux includes at least one of low-melting-point glass powder and water glass; the supplement is added at an amount of 1% to 3%, and the supplement includes at least one of phosphate rock powder, dolomite powder, and ferrous sulfate. Fluxes and supplements can be specifically added for different applications of the porous carrier. The use of the aforementioned flux can enhance the wear resistance of the porous carrier. The supplement can further adjust the composition and ratio of nutrients in the porous carrier. Therefore, the adaptability of the prepared porous carrier to specific applications can be improved.

[0038] In some embodiments, the pyrolysis activation treatment is carried out in an oxygen-deficient or oxygen-free atmosphere.

[0039] As an example, gneiss powder and organic matter are mixed and granulated to form a uniform powder, which is then transferred to a granulation device for granulation. During the mixing and granulation process, an appropriate amount of water is sprayed in as a wetting agent through a spraying device to control the material moisture content between 12% and 20% to achieve optimal plasticity. Granulation parameters are controlled to ensure that the resulting composite particles have a particle size within the range of 2mm to 8mm, giving the composite particles a certain compressive strength, which is beneficial for good transport and physical impact resistance during subsequent pyrolysis activation treatment. The granulation equipment can be a disc granulator, a roller extrusion granulator, or a drum granulator. If a disc granulator is used, spherical particles with relatively uniform particle size can be produced by adjusting the disc inclination angle and rotation speed. If a roller extrusion granulator is used, pillow-shaped or flaky particles with regular shapes can be produced. If a drum granulator is used, it is suitable for large-scale continuous production.

[0040] The composite particles are uniformly distributed and fed into a continuous or intermittent pyrolysis furnace (such as a rotary kiln or muffle furnace) in an oxygen-free or oxygen-deficient environment for programmed temperature-controlled pyrolysis activation. The heating rate is controlled at 5℃ / min to 20℃ / min, and when the furnace temperature reaches and is maintained at 400℃ to 650℃, isothermal pyrolysis is performed for 30 minutes to 120 minutes to obtain a porous carrier.

[0041] In a second aspect, this application proposes a porous carrier prepared using the method proposed in this application, comprising: biomass carbon; a mineral matrix dispersed in the biomass carbon, wherein the porous carrier has a specific surface area of ​​80 m². 2 / g~150m 2 / g.

[0042] In the porous carrier proposed in this application, biomass carbon with a porous structure and high specific surface area encapsulates a particulate mineral matrix. (Reference) Figure 1 , Figure 1 The porous carrier is prepared in granular form, comprising a mineral matrix 21 and biomass carbon 22 coating the mineral matrix. The mineral matrix in the porous carrier is mainly formed from gneiss powder through pyrolysis and activation. During the composite biomass carbon process, the mineral matrix undergoes effective pyrolysis, enhancing the release capacity of nutrients from the gneiss mineral matrix. The biomass carbon is mainly formed from biological organic matter through pyrolysis and activation. The biomass carbon coats the mineral matrix and has a high specific surface area, which helps maintain a certain moisture content in natural environments such as soil, improving the release capacity and efficiency of nutrients from the mineral matrix. The surface of the biomass carbon has numerous functional groups (such as hydroxyl, carboxyl, and carbonyl groups), which have good adsorption properties, promoting the release of nutrients from the mineral matrix and providing numerous attachment sites for microorganisms. This enhances the microbial immobilization effect of the porous carrier and improves the stability of microbial immobilization. Furthermore, this porous carrier also possesses good mechanical strength and water resistance, and is not prone to rapid disintegration in soil. Therefore, using the porous carrier of this application for soil improvement is beneficial to achieving the effect of stable and slow release of mineral nutrients, and using the composite microbial immobilization for soil improvement is beneficial to achieving better microbial synergistic effect.

[0043] In some embodiments, the total pore volume of the porous carrier is 0.15 cm³. 3 / g~0.30cm 3 / g. Within the aforementioned range, biomass carbon has a relatively rich pore structure and a large pore space, which is conducive to the full combination of biomass carbon with components such as water and soil in the environment and to maintaining the stability of its pore structure; the aforementioned particle size is conducive to the relatively uniform dispersion of mineral matrix in biomass carbon, and can be appropriately exposed through the pore structure of biomass carbon, so as to effectively contact environmental components and realize the release of mineral nutrients.

[0044] In a third aspect of this application, a composite sustained-release material is proposed, comprising a carrier and microorganisms loaded on the carrier; the carrier comprises the porous carrier proposed in this application, or a porous carrier prepared by the method proposed in this application.

[0045] The porous carrier of this application possesses a high specific surface area and abundant pore structure, providing ample habitat, reproduction space, and a protective barrier for the supported microorganisms. It exhibits good physicochemical stability, reducing the impact of environmental stresses such as ultraviolet radiation, drastic temperature changes, and fluctuations in soil pH on the supported microorganisms, thereby extending the survival time and activity period of functional strains in the soil and improving the stable performance of their functions such as potassium solubilization, nitrogen fixation, growth promotion, and pollutant degradation. The porous carrier itself is non-toxic and harmless, does not pollute the soil when used in the environment, and can provide some nutrients. Therefore, it can serve as a low-cost, high-performance microbial support carrier.

[0046] This porous carrier itself can slowly release mineral nutrients and has a high microbial loading efficiency. Furthermore, loading microorganisms not only further activates the nutrients contained in the porous carrier, facilitating the release of insoluble minerals, but the porous structure of biomass carbon also improves soil aeration and permeability, further enhancing the efficient loading of microorganisms. Therefore, applying this porous carrier for microbial loading can improve its overall effectiveness in promoting crop growth, improving infertile soils, and remediating polluted environments.

[0047] In some embodiments, the effective viable count of the microorganisms is greater than or equal to 10. 8 CFU / g.

[0048] In some embodiments, the microorganisms include one or more of potassium-solubilizing bacteria (such as Bacillus mucilaginosus), nitrogen-fixing bacteria (such as Azotobacter chroococcum), and phosphate-solubilizing bacteria (such as Bacillus megaterium) that participate in nutrient metabolism; and / or one or more of Pseudomonas, Bacillus lysinophils, and Bacillus neosphingolipids that degrade pollutants.

[0049] In some embodiments, the method for immobilizing microorganisms on porous carriers includes at least one of vacuum impregnation and atmospheric pressure adsorption.

[0050] In some embodiments, the method further includes drying the porous carrier loaded with functional microorganisms, wherein the drying method is at least one of freeze drying and low-temperature fluidized bed drying. This allows the loaded microorganisms to enter a dormant or semi-dormant state, extending the product's shelf life and improving the survival rate of the loaded microorganisms.

[0051] As an example, a method for loading microorganisms includes: sterilizing a cooled porous carrier by autoclaving or dry heat to eliminate contaminating microorganisms before inoculating it with the target functional microorganism; selecting the target functional microbial strain, for example, by scaling up the strain in a suitable liquid culture medium until the bacterial concentration reaches the end of the logarithmic growth phase (viable count not less than 10^6). 9(CFU / mL). The bacterial solution was inoculated onto the sterile carrier using either vacuum impregnation or atmospheric pressure adsorption. In the vacuum impregnation method, the sterile carrier particles were placed in a sealed container, and a vacuum of -0.08 MPa to -0.1 MPa was created and maintained for 5 to 15 minutes to remove air from the particle pores. Subsequently, a high-concentration bacterial solution was drawn into the container under negative pressure, allowing the solution to rapidly and uniformly penetrate the deep pores of the particles. After restoring to atmospheric pressure, the mixture was allowed to stand for 30 to 60 minutes for adsorption. In the atmospheric pressure adsorption method, the sterile carrier was directly immersed in a high-concentration bacterial solution. Microorganisms entered the pores through capillary action and diffusion; this process typically required a longer time (e.g., 6 to 24 hours), and stirring was used to improve uniformity. The loaded porous carrier was then dried. Drying methods include freeze-drying or low-temperature fluidized bed drying. Freeze-drying removes moisture under high vacuum conditions at temperatures below -40°C; low-temperature fluidized bed drying rapidly removes moisture from the particle surface and pores under conditions of 35°C~45°C and high air velocity. This yields a porous carrier loaded with microorganisms, which appears as uniform granules and has an effective viable bacterial count of up to 10-1. 8 CFU / g or higher.

[0052] The following specific embodiments illustrate the solution of this application. It should be noted that these embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0053] Example 1 1. Raw Material Pellet Preparation: Gneiss powder with a K2O content of 4.5% was dried and ball-milled until the particle size passed through a 200-mesh sieve (approximately 75 μm) to serve as the mineral matrix. Garden waste was used as the biological organic matter, dried, pulverized, and passed through an 80-mesh sieve. Commercially available sodium-based bentonite was used as the inorganic binder. 8 kg of gneiss powder, 1.5 kg of garden waste, and 0.5 kg of bentonite were weighed according to the following mass ratio. These three materials were placed in a horizontal ribbon mixer and dry-mixed for 20 minutes until homogeneous. The mixed dry powder was then fed into a roller extrusion granulator for granulation. During the granulation process, an appropriate amount of water was sprayed to control the material moisture content at 15%. The roller pressure was adjusted to obtain columnar composite pellets with a diameter of approximately 4 mm. The composite pellets were dried in an 80℃ hot air oven for 4 hours until the moisture content was <5%, and then set aside for use.

[0054] 2. Low-temperature pyrolysis activation: 2.5 kg of dried composite particles were loaded into an externally heated rotary kiln. Nitrogen gas (flow rate 1.5 L / min) was introduced to replace the air in the furnace, creating an oxygen-free environment. The heating program was started, and the temperature was increased to 550℃ at a rate of 10℃ / min. Pyrolysis was then carried out at this temperature for 60 minutes. This process allowed for complete carbonization and pore formation of the organic matter, while simultaneously inducing mineral lattice activation. After heating was stopped, the mixture was allowed to cool naturally to room temperature under nitrogen protection. A grayish-black porous mineral support was obtained.

[0055] 3. Material Performance Characterization: Performance tests were performed on the porous mineral support. The specific surface area of ​​the support was determined to be 125 m² using the nitrogen adsorption-desorption (BET) method. 2 / g, total pore volume is 0.18 cm³ 3 / g. For comparison... Figure 2 This illustrates that the gneiss powder raw material exhibits a dense, massive or flaky structure under an electron microscope, with no obvious pores. Figure 4 The diagram illustrates that the prepared porous support has a rough surface, filled with micron-sized pores left by the pyrolysis of organic matter. When immersed in water for 24 hours, the amount of water-soluble potassium ions dissolved from the porous support is 12 times that of the original gneiss powder.

[0056] 4. Microbial load: Take highly efficient potassium-solubilizing bacteria ( Bacillus mucilaginosus The strain was cultured in LB liquid medium at 30°C and 180 rpm for 48 hours with shaking, and the viable bacterial count reached 2 × 10⁻⁶. 9 CFU / mL. Vacuum impregnation was used for loading. 1 kg of sterilized porous carrier was placed in a vacuum chamber, and a vacuum of -0.09 MPa was maintained for 10 minutes. Air was then expelled from the pores using negative pressure. Bacterial solution was slowly aspirated until the carrier was completely submerged. The vacuum was then released, and the mixture was allowed to stand at normal pressure for 45 minutes for adsorption. The saturated porous carrier particles were removed, the surface liquid was drained, and the mixture was then dried in a freeze dryer at -50°C and a vacuum of 10 Pa for 24 hours to obtain the final product.

[0057] 5. Product Testing: The plate count method is used for testing, and the number of viable bacteria in the finished product is ≥2×10⁻⁶. 8 CFU / g, total potassium content (K2O) is approximately 4.0%.

[0058] Example 2 1. Raw material pellet preparation: Take 7.5 kg of gneiss powder and pass it through a 150-mesh sieve (approximately 100 μm); take 2 kg of municipal sludge (nitrogen content 3.5%, phosphorus content 1.2%) that has been dewatered and dried to a moisture content of 10% from a sewage treatment plant as biological organic matter, crush it and pass it through a 60-mesh sieve; take 0.5 kg of kaolin as an inorganic binder; mix the above raw materials evenly, and use a disc granulation method to mix and granulate the pellets, spray water mist as a wetting agent to obtain spherical composite pellets with a diameter of 3 mm to 6 mm, and pre-dry them at 90℃.

[0059] 2. Low-temperature pyrolysis activation: 2 kg of dried composite particles were placed in a muffle furnace and pyrolyzed in an oxygen-deficient environment (covered but not completely sealed). The temperature was increased to 480℃ at 8℃ / min and held at that temperature for 90 minutes. After cooling, a porous carrier was obtained.

[0060] 3. Material Performance Characterization: The performance of the porous support was tested. The specific surface area of ​​the support was determined to be 95 m² using the nitrogen adsorption-desorption method (BET method). 2 / g, total pore volume is 0.26 cm³ 3 / g. Mercury porosimetry analysis showed that the material has abundant macropores in the 100nm~500nm range, which is beneficial for the adsorption of macromolecular pollutants (such as PAHs).

[0061] 4. Microbial load: A strain of Pseudomonas aeruginosa capable of efficiently degrading polycyclic aromatic hydrocarbons (PAHs) was selected. Pseudomonas sp. The culture was carried out until the late logarithmic phase. Using an atmospheric pressure adsorption method, the sterilized porous carrier was immersed in the bacterial solution and shaken on a shaker at 50 rpm for 12 hours. Then, it was dried at 40℃ in a fluidized bed until the moisture content was <10%. This yielded a mineral-based biocomposite material loaded with PAHs-degrading bacteria.

[0062] 5. Application Test: The composite material was applied at a ratio of 5% to phenanthrene-contaminated soil (initial phenanthrene concentration: 100 mg / kg). After 14 days, test results showed that the phenanthrene degradation rate reached 85%, while the degradation rate of the control group sprayed with bacterial solution was only 45%. This indicates that the porous structure of the material not only adsorbed pollutants but also created a high-concentration reaction zone for microorganisms, improving bioremediation efficiency.

[0063] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0064] In this application, the order in which the steps are written does not imply a strict execution order and does not limit the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps in this application can be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0065] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing a porous support, characterized in that, include: Composite particles are obtained by mixing and granulating gneiss powder, biological organic matter, and inorganic binder. The composite particles are subjected to pyrolysis activation treatment to obtain the porous carrier; Based on the mass of the composite particles, the percentage by mass is as follows: the gneiss powder accounts for 60% to 90%, the biological organic matter accounts for 8% to 35%, and the inorganic binder accounts for 2% to 8%.

2. The method according to claim 1, characterized in that, The temperature of the pyrolysis activation treatment is 400℃~650℃; and / or, The heating rate of the pyrolysis activation treatment is 5℃ / min to 20℃ / min.

3. The method according to claim 1, characterized in that, The Dv50 particle size of the gneiss powder is 50 μm to 150 μm; and / or, The inorganic binder includes at least one of bentonite, kaolin, or attapulgite.

4. The method according to any one of claims 1 to 3, characterized in that, At least one of the following conditions must be met: The Dv50 particle size of the biological organic matter is 150μm~250μm; The water content of the biological organic matter is less than or equal to 10%; The biological organic matter includes at least one of agricultural waste, wood processing waste, garden waste, and municipal sludge.

5. The method according to any one of claims 1 to 3, characterized in that, The composite particles also include at least one of a flux and a supplement. The flux is added at a rate of 1% to 3%, and the flux includes at least one of low-melting-point glass powder and water glass; the supplement is added at a rate of 1% to 3%, and the supplement includes at least one of phosphate rock powder, dolomite powder, and ferrous sulfate.

6. A porous carrier, characterized in that, Prepared using the method described in any one of claims 1 to 5, comprising: Biomass carbon; A mineral matrix, wherein the mineral matrix is ​​dispersed in the biomass carbon, and the porous carrier has a specific surface area of ​​80 m². 2 / g~150m 2 / g.

7. The porous carrier according to claim 6, characterized in that, The total pore volume of the porous carrier is 0.15 cm³. 3 / g~0.30cm 3 / g.

8. A composite sustained-release material, characterized in that, It includes a carrier and microorganisms loaded on the carrier; the carrier includes the porous carrier of claim 6 or 7, or the porous carrier prepared by the method of any one of claims 1 to 5.

9. The composite sustained-release material according to claim 8, characterized in that, The effective viable count of the microorganism is greater than or equal to 10. 8 CFU / g.

10. The composite sustained-release material according to claim 8, characterized in that, The microorganisms include one or more of potassium-solubilizing bacteria, nitrogen-fixing bacteria, and phosphate-solubilizing bacteria that participate in nutrient metabolism; and / or one or more of Pseudomonas, Bacillus, and Neosphingolipids that degrade pollutants.

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