Ecological slow-release carbon source and preparation method thereof

Abstract

The invention relates to the technical field of sewage treatment, and particularly discloses an ecological slow-release carbon source and a preparation method thereof. The ecological slow-release carbon source comprises the following raw materials in parts by weight: 30-50 parts of beewax, 20-40 parts of water-soluble polysaccharide, 5-15 parts of a water-soluble polymer, 3-10 parts of a biodegradable elastomer and 10-20 parts of a porous mineral material. The hydrophilic property and the mechanical property of the slow-release carbon source with the beewax as the slow-release matrix can be improved under the condition that the slow-release characteristic of the slow-release carbon source with the beewax as the slow-release matrix is maintained.

Description

Technical Field

[0001] This invention relates to the technical field of wastewater treatment, and in particular to an ecological slow-release carbon source and its preparation method. Background Technology

[0002] In biological denitrification processes of wastewater with low carbon-to-nitrogen ratios (C / N) or slightly polluted rivers and lakes, additional carbon sources are required to drive the denitrification process. Solid slow-release carbon sources have attracted much attention due to their advantages such as slow release, long-lasting effect, and ease of operation and management. However, existing technologies mostly use synthetic polymers such as polycaprolactone and polyhydroxyalkanoates, or single natural polymers such as starch, as the main materials. Synthetic polymers are costly and have poor environmental sustainability, and they also suffer from problems such as low strength, easy disintegration, and excessively rapid or uncontrollable carbon release rates.

[0003] Beeswax, as a widely available and renewable natural substance, can serve as a carbon source for microorganisms and is a potentially excellent slow-release matrix. However, directly developing beeswax as a slow-release carbon source faces three inherent technical bottlenecks: ① Strong hydrophobicity: The strong hydrophobicity of beeswax makes initial wetting difficult, preventing microorganisms from effectively utilizing it, resulting in a "carbon starvation" start-up period. ② Poor mechanical properties: Pure beeswax is brittle and has low strength, making molded products fragile and difficult to maintain structural integrity under actual hydraulic conditions. ③ Difficulty in release control: Its release mainly relies on its own slow biodegradation or physical dissolution, resulting in a slow release rate that is difficult to control according to treatment needs. Moreover, although existing technologies have attempted to blend beeswax with other materials, these are mostly simple physical mixtures, failing to systematically and comprehensively resolve the aforementioned performance contradictions, often resulting in compromises.

[0004] Therefore, it is necessary to improve the characteristics of beeswax, such as strong hydrophobicity, poor mechanical properties and difficulty in release regulation, and develop an ecological slow-release carbon source with beeswax as the slow-release matrix, so as to improve the hydrophilicity and mechanical properties of the ecological slow-release carbon source without significantly weakening the slow-release characteristics. Summary of the Invention

[0005] In order to improve the hydrophilicity and mechanical properties of a sustained-release carbon source using beeswax as a sustained-release matrix while maintaining its sustained-release characteristics, this application provides an ecological sustained-release carbon source and its preparation method.

[0006] Firstly, this application provides an ecologically slow-release carbon source, which adopts the following technical solution: An eco-friendly slow-release carbon source comprises the following raw materials in parts by weight: 30-50 parts beeswax, 20-40 parts water-soluble polysaccharide, 5-15 parts water-soluble polymer, 3-10 parts biodegradable elastomer, and 10-20 parts porous mineral material.

[0007] By employing the above technical solution, beeswax serves as the slow-release framework and structural body of the entire slow-release carbon source. Biodegradable elastomers are interwoven within the beeswax, which, on the one hand, enhances the overall toughness of the slow-release carbon source, preventing cracking and subsequent explosive carbon release; on the other hand, the degradation rate of the biodegradable elastomers is between that of beeswax and water-soluble components, allowing for regulation of the overall carbon source release rate and avoiding problems of excessively rapid initial release or insufficient release later. Water-soluble polysaccharides are uniformly dispersed within the hydrophobic beeswax, forming hydrophilic microdomains. When the slow-release carbon source is added to water, these hydrophilic microdomains rapidly absorb water and dissolve, providing microorganisms with an immediately usable starting carbon source, reducing the lag in starting pure beeswax carbon sources; they also leave numerous micropores in situ within the originally dense beeswax matrix, significantly increasing the contact area between water and the internal beeswax. Water-soluble polymers interpenetrate with the beeswax and biodegradable elastomer network, partially binding with water-soluble polysaccharides, forming a more stable and continuous hydrophilic polymer network channel based on the pore-forming effect of the dissolved water-soluble polysaccharides. These channels continuously guide water into the material's interior and transport dissolved small-molecule beeswax or degradation products out, thereby systematically and persistently improving the overall hydrophilicity and mass transfer efficiency of the entire slow-release carbon source. The porous mineral material dispersed within the beeswax and elastomer effectively prevents crack propagation, improves the compressive strength and dimensional stability of the slow-release carbon source, and prevents it from softening and deforming in water. Simultaneously, the abundant surface and pores of the porous mineral material facilitate preferential attachment of microorganisms, enabling biofilms to grow stably on the carbon source surface and within its internal pores, achieving in-situ consumption of the carbon source and further improving utilization efficiency and release stability. Therefore, this application can improve the hydrophilicity and mechanical properties of a slow-release carbon source using beeswax as the slow-release matrix while maintaining its slow-release characteristics.

[0008] In one specific implementation, the biodegradable elastomer comprises at least one of polybutylene adipate terephthalate, polybutylene succinate, polycaprolactone, or a copolymer of polybutylene adipate terephthalate, polybutylene succinate, and polycaprolactone.

[0009] By adopting the above-mentioned technical solutions, polybutylene adipate terephthalate, polybutylene succinate, polycaprolactone and their copolymers share certain similarities in chemical structure with beeswax. Therefore, they can achieve good mutual dissolution and dispersion in the molten state, forming a uniform blend phase, which helps to construct a stable interpenetrating network. Moreover, the aforementioned specific types of biodegradable elastomers have suitable melting temperature ranges, allowing them to be blended with beeswax at the same melting processing temperature without decomposition, ensuring the feasibility of the preparation process. Therefore, using the aforementioned specific types of biodegradable elastomers can significantly improve the toughness, impact resistance, and elongation at break of ecologically released carbon sources, helping the released carbon sources maintain their predetermined shape and size in water, avoiding softening and deformation, and ensuring their reliability in hydraulic flushing or filling applications. In addition, after fulfilling their carbon source release mission, the aforementioned specific types of biodegradable elastomers can also be gradually decomposed into CO2 and water by environmental microorganisms, without causing secondary microplastic pollution.

[0010] In one specific implementation, the porous mineral material includes at least one of diatomaceous earth, bentonite, zeolite powder, or biochar.

[0011] By employing the above-mentioned technical solutions, diatomaceous earth, bentonite, zeolite powder, or biochar are rigid inorganic particles with high modulus and hardness. Dispersed in beeswax and biodegradable elastomers, they significantly improve the compressive strength, creep resistance, and dimensional stability of the ecologically slow-release carbon source, preventing deformation and collapse during storage, transportation, or underwater hydraulic pressure environments. Diatomaceous earth, bentonite, zeolite powder, and biochar all possess abundant, interconnected pores. These pores can form a mass transfer channel network, helping to improve the efficiency of diffusion and exchange of water molecules, dissolved oxygen, nutrients, and metabolic products within the carbon source.

[0012] In one specific implementation, the water-soluble polysaccharide includes one or more of maltodextrin, soluble starch, and β-cyclodextrin.

[0013] By adopting the above technical solutions, all three polysaccharides are carbon sources that are easily and rapidly enzymatically hydrolyzed and utilized by most heterotrophic microorganisms. When any of the above water-soluble polysaccharides is dispersed in beeswax, it dissolves rapidly upon addition to water, providing an immediately usable starting carbon source for microorganisms. This avoids the problem of delayed denitrification initiation caused by the hydrophobic and extremely slow release of pure beeswax carbon sources in the initial stage of addition, ensuring that the denitrification process can proceed immediately and efficiently. The dispersion of these three polysaccharides in hydrophobic beeswax creates numerous hydrophilic regions. When in contact with water, these hydrophilic regions rapidly absorb water, greatly improving the wettability of the slow-release carbon source surface and reducing water permeation resistance.

[0014] In one specific implementation, the water-soluble polymer includes one or more of polyvinyl alcohol, polyethylene glycol, and hydroxypropyl methylcellulose.

[0015] By employing the above technical solutions, polysaccharides dissolve and leave pores, but the chemical properties of the channel walls determine whether water can continuously and stably wet and permeate. The three water-soluble polymers mentioned above can modify the wall properties of the pores formed by polysaccharide dissolution, making them more hydrophilic and smoother, thus reducing flow resistance. Therefore, the hydrophilicity of the slow-release carbon source can be improved.

[0016] In one specific implementation, the water-soluble polymer is polyethylene glycol with a molecular weight of 1000 to 6000.

[0017] By adopting the above technical solution, polyethylene glycol with a molecular weight of 1000-6000 has excellent water solubility. Its dissolution process can promote faster dissolution and more uniform leaching of water-soluble polysaccharides, which helps to form a more unobstructed and interconnected pore network.

[0018] In one specific implementation, the eco-slow-release carbon source also includes an auxiliary foaming agent.

[0019] By adopting the above technical solution, the auxiliary foaming agent decomposes to generate gas during heating and curing, which can form a preliminary cell structure inside the carbon source in the early stage, which helps to further improve the overall hydrophilicity and mass transfer efficiency of the entire ecological slow-release carbon source.

[0020] In one specific implementation, the auxiliary foaming agent is ammonium bicarbonate or citric acid.

[0021] By adopting the above technical solutions, ammonium bicarbonate or citric acid can form pores inside the material through thermal decomposition or gas generation, and the process is mild and easy to control.

[0022] Secondly, this application provides a method for preparing an ecologically slow-release carbon source, which adopts the following technical solution: A method for preparing an ecologically slow-release carbon source includes the following steps: S1. Heat the beeswax to 80-85℃ until it is completely melted. Then, under the condition of heat preservation and shearing stirring, add biodegradable elastomer, water-soluble polymer, water-soluble polysaccharide and porous mineral material in sequence. Shear and stir evenly to obtain a viscous slurry. S2. Pour the viscous slurry into a mold at 50-60℃ and cure the mold as follows: First, heat to 75-85℃ and hold for 10-30 minutes. Second, cool down to 25-35℃ at a rate of 2-5℃ / min and hold for 2-4 hours to complete the curing and molding process, and obtain the initial carbon source. S3. Demold the primary carbon source, soak it in deionized water for 12–48 hours, and then dry it at 40–50°C to constant weight to obtain an ecologically slow-release carbon source.

[0023] By employing the above technical solution, a temperature of 80–85℃, slightly higher than the melting point of beeswax, can completely melt beeswax into a continuous phase with good fluidity and a basic carrier, while avoiding excessive temperature that could lead to degradation of beeswax or other heat-sensitive components. Sequential feeding under heat preservation and shear stirring can break up the agglomeration of each component, achieving uniform dispersion of each component in the beeswax melt. Injecting into a mold at 50–60℃ prevents rapid surface solidification of the slurry upon contact with the cold mold wall, avoiding defects or internal stress, and ensuring the product's intact shape and uniform internal structure. Heating to 75–85℃ and maintaining it for 10–30 minutes allows for thorough and uniform decomposition and gas generation in the slurry, forming fine bubbles and providing sufficient time for the polymer molecular chains to move, rearrange, and entangle, strengthening the formation of the interpenetrating network structure. Programmed cooling to 25–35℃ allows the beeswax, elastomers, and other crystalline components to crystallize in an orderly manner, forming a more complete crystal structure, further improving the mechanical strength and sustained-release stability of the slow-release carbon source. After soaking in water for 12–48 hours and then drying at a low temperature of 40–50°C, water-soluble polysaccharides and polymers are selectively dissolved and leached out. The spaces they originally occupied are transformed in situ into an interconnected, open network of pores, resulting in excellent hydrophilicity and a high specific surface area for the slow-release carbon source. Simultaneously, some insoluble but hydrophilic polymers absorb water and swell, forming a stable hydrophilic gel layer on the inner wall of the pores, ensuring long-term hydrophilicity and stability. The soaking process also removes some readily soluble carbon sources, preventing explosive release of carbon during the initial addition. The low temperature avoids the softening of beeswax and polymer deformation that can occur with high temperatures, thus perfectly preserving the porous structure formed during water soaking and obtaining a finished product with the predetermined shape, strength, porosity, and water content.

[0024] In one specific feasible implementation, in step S1, the biodegradable elastomer is pre-cut into particles with a particle size ≤ 5 mm.

[0025] By adopting the above technical solution, the contact area with molten beeswax can be greatly increased, allowing heat to be transferred to the interior of the elastomer more quickly and evenly, promoting rapid and uniform melting or softening. Under high-speed shearing and stirring, small particles are more easily broken up, torn apart, and dispersed into the beeswax melt. If large blocks of elastomer are added directly, insufficient melting or uneven dispersion can easily lead to structural defects and weak points in the material's performance.

[0026] In summary, this application has the following beneficial effects: 1. This application uses a limited ratio of beeswax, water-soluble polysaccharides, water-soluble polymers, biodegradable elastomers and porous mineral materials to prepare an ecological slow-release carbon source, which can improve the hydrophilicity and mechanical properties of the slow-release carbon source with beeswax as the slow-release matrix while maintaining the slow-release characteristics of the slow-release carbon source with beeswax as the slow-release matrix.

[0027] 2. In this application, specific types of water-soluble polysaccharides, water-soluble polymers, biodegradable elastomers and porous mineral materials are preferred, and auxiliary foaming agents are added, which can further improve the overall hydrophilicity and mass transfer efficiency of the entire ecological slow-release carbon source.

[0028] 3. The method of this application can avoid the degradation of beeswax or other heat-sensitive components due to excessively high temperature, prevent the surface of the slurry from rapidly solidifying and generating defects or internal stress when it comes into contact with the cold mold wall, ensure the integrity of the product shape and the uniformity of the interior, further improve the mechanical strength and slow-release stability of the slow-release carbon source, maintain the porous structure formed by water immersion, and obtain a finished product with a predetermined shape, strength, porosity and moisture content. Detailed Implementation

[0029] Unless otherwise specified, all raw materials used in this application were commercially available. Specifically, the beeswax was yellow beeswax, CAS No. 8012-89-3, purchased from Henan Dazheng Chemical Products Co., Ltd. Maltodextrin, model XH5280GIDG25, was purchased from Jinan Shenghe Chemical Co., Ltd. Hydroxypropyl methylcellulose, CAS No. 9004-62-0, with an active ingredient content of 98%. Polybutylene adipate terephthalate, CAS No. 55231-08-8, was purchased from Hubei Chengfeng Chemical Co., Ltd. Diatomaceous earth, SiO2 content 85%, was purchased from Shijiazhuang Jucai Mineral Products Co., Ltd. Ammonium bicarbonate, with an active ingredient content of 99%. Soluble starch, CAS No. 9005-84-9, was purchased from Shandong Pingju Biotechnology Co., Ltd. Biochar was straw biochar purchased from Henan Xingnuo Environmental Protection Materials Co., Ltd. Citric acid, CAS No. 77-92-9, AR grade.

[0030] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0031] Example 1 This embodiment provides an ecological slow-release carbon source, comprising the following raw materials: 40 kg beeswax, 30 kg maltodextrin, 10 kg hydroxypropyl methylcellulose, 5 kg polybutylene adipate, and 15 kg diatomaceous earth.

[0032] This embodiment also provides a method for preparing an ecologically slow-release carbon source, including the following steps: S1. Heat the beeswax to 80-85℃ and keep it at this temperature until it is completely melted. Then, while keeping it warm and stirring at a high speed of 2000 rpm, add polybutylene adipate terephthalate, hydroxypropyl methylcellulose, maltodextrin and diatomaceous earth in sequence. Continue to stir and shear for 30 minutes until uniform to obtain a viscous slurry.

[0033] S2. Inject the viscous slurry into a mold preheated to 55°C, and then cure the mold as follows: First, heat the mold to 80°C and hold for 20 minutes. Second, cool the mold to 30°C at a rate of 3°C / min and hold for 3 hours to complete the curing and molding process, thus obtaining the initial carbon source.

[0034] S3. Demold the primary carbon source, soak it in deionized water for 30 hours, and then dry it at 45°C to constant weight to obtain the ecological slow-release carbon source.

[0035] Example 2 The only difference between this embodiment and Embodiment 1 is that the ecological slow-release carbon source includes the following raw materials: 30 kg of beeswax, 25 kg of maltodextrin, 15 kg of hydroxypropyl methylcellulose, 10 kg of polybutylene adipate, and 20 kg of diatomaceous earth.

[0036] Example 3 The only difference between this embodiment and Embodiment 1 is that the ecological slow-release carbon source includes the following raw materials: 50 kg of beeswax, 5 kg of maltodextrin, 15 kg of hydroxypropyl methylcellulose, 10 kg of polybutylene adipate, and 20 kg of diatomaceous earth.

[0037] Example 4 The only difference between this embodiment and Embodiment 1 is that the ecological slow-release carbon source includes the following raw materials: 50 kg of beeswax, 32 kg of maltodextrin, 5 kg of hydroxypropyl methylcellulose, 3 kg of polybutylene adipate, and 10 kg of diatomaceous earth.

[0038] Example 5 This embodiment provides an ecological slow-release carbon source, comprising the following raw materials: 40 kg beeswax, 30 kg maltodextrin, 10 kg hydroxypropyl methylcellulose, 5 kg polybutylene adipate, 14 kg diatomaceous earth, and 1 kg ammonium bicarbonate.

[0039] This embodiment also provides a method for preparing an ecologically slow-release carbon source, including the following steps: S1. Heat the beeswax to 80-85℃ and maintain it within this temperature range until it is completely melted. Then, while keeping it warm and stirring at a high speed of 2000 rpm, add polybutylene adipate terephthalate, hydroxypropyl methylcellulose, maltodextrin, and diatomaceous earth in sequence. Continue to stir and shear for 30 minutes until uniform. Add ammonium bicarbonate and continue to stir at high speed for 5-10 minutes to obtain a viscous slurry.

[0040] S2. Inject the viscous slurry into a mold preheated to 55°C, and then cure the mold as follows: First, heat the mold to 80°C and hold for 20 minutes. Second, cool the mold to 30°C at a rate of 3°C / min and hold for 3 hours to complete the curing and molding process, thus obtaining the initial carbon source.

[0041] S3. Demold the primary carbon source, soak it in deionized water for 30 hours, and then dry it at 45°C to constant weight to obtain the ecological slow-release carbon source.

[0042] Example 6 The only difference between this embodiment and embodiment 5 is that the ecological slow-release carbon source includes the following raw materials: 38 kg of beeswax, 35 kg of maltodextrin, 12 kg of hydroxypropyl methylcellulose, 4 kg of polybutylene adipate, 10 kg of diatomaceous earth, and 1 kg of ammonium bicarbonate.

[0043] Example 7 The only difference between this embodiment and embodiment 5 is that the ecological slow-release carbon source includes the following raw materials: 45 kg of beeswax, 25 kg of maltodextrin, 8 kg of hydroxypropyl methylcellulose, 8 kg of polybutylene adipate, 13 kg of diatomaceous earth, and 1 kg of ammonium bicarbonate.

[0044] Example 8 The only difference between this embodiment and embodiment 5 is that the ecological slow-release carbon source includes the following raw materials: 35 kg of beeswax, 25 kg of soluble starch, 8 kg of polyethylene glycol with a molecular weight of 3500, 8 kg of polybutylene succinate, 20 kg of biochar, and 4 kg of ammonium bicarbonate.

[0045] The preparation method of ecological slow-release carbon source includes the following steps: S1. Heat the beeswax to 80-85℃ and maintain it within this temperature range until it is completely melted. Then, while keeping it warm and stirring at a high speed of 2000 rpm, add polybutylene succinate, polyvinyl alcohol, soluble starch and biochar in sequence. Continue to stir and shear for 30 minutes until uniform. Add ammonium bicarbonate and continue to stir at high speed for 5-10 minutes to obtain a viscous slurry.

[0046] S2. Inject the viscous slurry into a mold preheated to 55°C, and then cure the mold as follows: First, heat the mold to 80°C and hold for 20 minutes. Second, cool the mold to 30°C at a rate of 3°C / min and hold for 3 hours to complete the curing and molding process, thus obtaining the initial carbon source.

[0047] S3. Demold the primary carbon source, soak it in deionized water for 30 hours, and then dry it at 45°C to constant weight to obtain the ecological slow-release carbon source.

[0048] Example 9 The only difference between this embodiment and Embodiment 8 is that an equal amount of polyethylene glycol with a molecular weight of 1000 is used to replace polyethylene glycol with a molecular weight of 3500.

[0049] Example 10 The only difference between this embodiment and Embodiment 8 is that an equal amount of polyethylene glycol with a molecular weight of 6000 is used to replace polyethylene glycol with a molecular weight of 3500.

[0050] Example 11 The only difference between this embodiment and Embodiment 8 is that an equal amount of citric acid is used to replace ammonium bicarbonate.

[0051] Example 12 The only difference between this embodiment and Embodiment 1 is that the preparation method of the ecologically slow-release carbon source includes the following steps: S1. Heat the beeswax to 80-85℃ and keep it at this temperature until it is completely melted. Then, while keeping it warm and stirring at a high speed of 2000 rpm, add polybutylene adipate terephthalate, hydroxypropyl methylcellulose, maltodextrin and diatomaceous earth in sequence. Continue to stir and shear for 30 minutes until uniform to obtain a viscous slurry.

[0052] S2. Inject the viscous slurry into a mold preheated to 50°C, and then cure the mold as follows: First, heat the mold to 75°C and hold for 10 minutes. Second, cool the mold to 25°C at a rate of 2°C / min and hold for 2 hours to complete the curing and molding process, thus obtaining the initial carbon source.

[0053] S3. Demold the primary carbon source, soak it in deionized water for 12 hours, and then dry it at 40°C to constant weight to obtain the ecological slow-release carbon source.

[0054] Example 13 The only difference between this embodiment and Embodiment 1 is that the preparation method of the ecologically slow-release carbon source includes the following steps: S1. Heat the beeswax to 80-85℃ and keep it at this temperature until it is completely melted. Then, while keeping it warm and stirring at a high speed of 2000 rpm, add polybutylene adipate terephthalate, hydroxypropyl methylcellulose, maltodextrin and diatomaceous earth in sequence. Continue to stir and shear for 30 minutes until uniform to obtain a viscous slurry.

[0055] S2. Inject the viscous slurry into a mold preheated to 60°C, and then cure the mold as follows: First, heat the mold to 85°C and hold for 30 minutes. Second, cool the mold to 35°C at a rate of 5°C / min and hold for 4 hours to complete the curing and molding process, thus obtaining the initial carbon source.

[0056] S3. Demold the primary carbon source, soak it in deionized water for 48 hours, and then dry it at 50°C to constant weight to obtain the ecological slow-release carbon source.

[0057] Example 14 The only difference between this embodiment and Embodiment 1 is that the preparation method of the ecologically slow-release carbon source includes the following steps: S1. Pre-cut the biodegradable elastomer into particles with a diameter ≤5mm; heat the beeswax to a temperature range of 80-85℃, and after completely melting the beeswax within this temperature range, add polybutylene adipate, hydroxypropyl methylcellulose, maltodextrin and diatomaceous earth in sequence under heat preservation and high-speed shearing and stirring at 2000rpm, and continue shearing and stirring for 30 minutes until uniform to obtain a viscous slurry.

[0058] S2. Inject the viscous slurry into a mold preheated to 55°C, and then cure the mold as follows: First, heat the mold to 80°C and hold for 20 minutes. Second, cool the mold to 30°C at a rate of 3°C / min and hold for 3 hours to complete the curing and molding process, thus obtaining the initial carbon source.

[0059] S3. Demold the primary carbon source, soak it in deionized water for 30 hours, and then dry it at 45°C to constant weight to obtain the ecological slow-release carbon source.

[0060] Comparative Example Comparative Example 1 The only difference between this comparative example and Example 1 is that the eco-slow-release carbon source consists solely of beeswax. The beeswax was heated to 80–85°C and kept at this temperature until completely melted. The melted beeswax was then poured into a mold preheated to 55°C. The mold was then cured as follows: First, the temperature was raised to 80°C and held for 20 minutes. Second, the temperature was lowered to 30°C at a rate of 3°C / min and held for 3 hours to complete the curing process, yielding the initial carbon source. The initial carbon source was demolded, soaked in deionized water for 30 hours, and then dried at 45°C to constant weight to obtain the eco-slow-release carbon source.

[0061] Comparative Example 2 The only difference between this comparative example and Example 1 is that the ecologically controlled carbon source includes 50 kg of beeswax and 50 kg of soluble starch. The preparation method of the ecologically controlled carbon source includes the following steps: S1. Heat the beeswax to a temperature range of 80-85℃ and maintain it within this temperature range until the beeswax is completely melted. Then, while keeping it warm, add soluble starch and continue to shear and stir at a high speed of 2000 rpm for 30 minutes until uniform, to obtain a viscous slurry.

[0062] S2. Inject the viscous slurry into a mold preheated to 55°C, and then cure the mold as follows: First, heat the mold to 80°C and hold for 20 minutes. Second, cool the mold to 30°C at a rate of 3°C / min and hold for 3 hours to complete the curing and molding process, thus obtaining the initial carbon source.

[0063] S3. Demold the primary carbon source, soak it in deionized water for 30 hours, and then dry it at 45°C to constant weight to obtain the ecological slow-release carbon source.

[0064] Comparative Example 3 The only difference between this comparative example and Example 1 is that the ecological slow-release carbon source includes 40 kg of beeswax, 30 kg of maltodextrin, 10 kg of hydroxypropyl methylcellulose, and 20 kg of diatomaceous earth. The preparation method of the ecological slow-release carbon source includes the following steps: S1. Heat the beeswax to 80-85℃ and keep it at this temperature until it is completely melted. Then, while keeping it warm, add maltodextrin, hydroxypropyl methylcellulose and diatomaceous earth in sequence under high-speed shearing and stirring at 2000 rpm. Continue shearing and stirring for 30 minutes until uniform to obtain a viscous slurry.

[0065] S2. Inject the viscous slurry into a mold preheated to 55°C, and then cure the mold as follows: First, heat the mold to 80°C and hold for 20 minutes. Second, cool the mold to 30°C at a rate of 3°C / min and hold for 3 hours to complete the curing and molding process, thus obtaining the initial carbon source.

[0066] S3. Demold the primary carbon source, soak it in deionized water for 30 hours, and then dry it at 45°C to constant weight to obtain the ecological slow-release carbon source.

[0067] Comparative Example 4 The only difference between this comparative example and Example 1 is that the ecological slow-release carbon source includes 45 kg of beeswax, 30 kg of maltodextrin, 5 kg of polybutylene adipate terephthalate, and 20 kg of diatomaceous earth. The preparation method of the ecological slow-release carbon source includes the following steps: S1. Heat the beeswax to 80-85℃ and keep it at this temperature until it is completely melted. Then, while keeping it warm and stirring at a high speed of 2000 rpm, add maltodextrin, polybutylene adipate terephthalate and diatomaceous earth in sequence. Continue to stir for 30 minutes until uniform to obtain a viscous slurry.

[0068] S2. Inject the viscous slurry into a mold preheated to 55°C, and then cure the mold as follows: First, heat the mold to 80°C and hold for 20 minutes. Second, cool the mold to 30°C at a rate of 3°C / min and hold for 3 hours to complete the curing and molding process, thus obtaining the initial carbon source.

[0069] S3. Demold the primary carbon source, soak it in deionized water for 30 hours, and then dry it at 45°C to constant weight to obtain the ecological slow-release carbon source.

[0070] Comparative Example 5 The only difference between this comparative example and Example 1 is that step S3 of the method for preparing the ecological slow-release carbon source is as follows: the initial carbon source is demolded and dried at 45°C to constant weight to obtain the ecological slow-release carbon source.

[0071] Performance testing The following performance tests were conducted on Examples 1-14 and Comparative Examples 1-5: ① Using an optical contact angle meter and the static drop method, the water contact angle of the ecological slow-release carbon source was measured on a flat surface of the ecological slow-release carbon source, and the average value of 5 different locations was taken.

[0072] ② The total intrusive pore volume of the ecological slow-release carbon source was measured using the mercury porosimetry method and a fully automated mercury porosimetry instrument, and the porosity was calculated.

[0073] ③ Using a universal testing machine, compress the ecological slow-release carbon source (cylinder Φ10mm×10mm) at a rate of 1 mm / min until the maximum stress value when the sample height is reduced by 20% to obtain the compressive strength.

[0074] ④ Support the long strip sample (60mm×10mm×5mm) at both ends, apply force to the center, and observe the maximum bending angle before it breaks, which is the degree of bending.

[0075] ⑤ Using the simulated static water immersion method, the precisely weighed sample was placed in a conical flask containing deionized water and oscillated at a constant temperature (25℃, 100rpm) to accumulate the carbon release rate.

[0076] Periodically sample and determine the total organic carbon (TOC) concentration in the water, and calculate the percentage of cumulative carbon release relative to the total soluble carbon source.

[0077] The test results are shown in Table 1.

[0078] Table 1 Based on Example 1 and Comparative Examples 1-5, and referring to Table 1, it can be seen that, compared to Example 1, Comparative Example 1 has an excessively large water contact angle, excessively low porosity and compressive strength, extremely poor tortuosity, and releases almost no carbon within 90 days. This indicates that pure beeswax cannot be directly used as a slow-release carbon source.

[0079] Compared to Example 1, Comparative Examples 2-5 all had water contact angles greater than 80°, reduced porosity, significantly decreased compressive strength, and exhibited poorer tortuosity and sustained-release performance. This indicates that Comparative Example 2 showed improved hydrophilicity but lacked pore formation and toughening mechanisms, resulting in a soft, rapidly disintegrating material exhibiting a burst release phenomenon and failing to achieve sustained-release functionality. Comparative Example 3, lacking an elastomer toughening network, had approximately 50% lower compressive strength, poor tortuosity, and almost complete carbon release due to structural failure on day 90. This demonstrates the indispensability of PBAT / PBS-type elastomers in providing mechanical support, maintaining long-term structural stability, and thus achieving true sustained-release. Comparative Example 4, lacking HPMC as a pore-forming template, had extremely low porosity, resulting in a high water contact angle, poor hydrophilicity, and obstructed carbon source release channels, leading to a cumulative release rate far lower than Example 1 over 90 days. The porosity of Comparative Example 5 mainly comes from the foaming agent, and the pores are not interconnected, resulting in significantly lower hydrophilicity and carbon release efficiency compared to Example 1. This directly demonstrates the decisive influence of the water immersion pore-forming process on forming interconnected hydrophilic pores and optimizing release behavior, and is an innovative process that differs from simple physical foaming.

[0080] Therefore, by adopting the raw material ratio and preparation method of Example 1, the hydrophilicity and mechanical properties of the sustained-release carbon source with beeswax as the sustained-release matrix can be improved while maintaining the sustained-release characteristics of the sustained-release carbon source with beeswax as the sustained-release matrix.

[0081] As can be seen from Examples 1-14 and Table 1, using the raw material ratios and preparation methods within the range of Examples 1-14 can improve the hydrophilicity and mechanical properties of the sustained-release carbon source with beeswax as the sustained-release matrix while maintaining the sustained-release characteristics of the sustained-release carbon source with beeswax as the sustained-release matrix.

[0082] Comparing the test data of Examples 5-7, it can be seen that Example 6, by increasing the proportion of hydrophilic components HPMC and maltodextrin, achieved a lower contact angle and a higher initial carbon release rate, making it suitable for wastewater treatment scenarios requiring rapid start-up. Example 7, by increasing the proportion of beeswax and elastomer, achieved higher strength, a more hydrophobic surface, and a smoother long-term release, making it suitable for remediation scenarios with long hydraulic retention times or requiring long-term maintenance.

[0083] By comparing the test data of Examples 5 and 8, it can be seen that the substitutability of water-soluble polymers and elastomers, as well as the performance differences brought about by different porous carriers, prove that the formulation system of the present invention has a wide range of material selection and control space.

[0084] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An ecologically slow-release carbon source, characterized in that, The raw materials include the following parts by weight: 30-50 parts beeswax, 20-40 parts water-soluble polysaccharide, 5-15 parts water-soluble polymer, 3-10 parts biodegradable elastomer, and 10-20 parts porous mineral material.

2. The ecologically slow-release carbon source according to claim 1, characterized in that, The biodegradable elastomer includes at least one of polybutylene adipate terephthalate, polybutylene succinate, polycaprolactone, or a copolymer of polybutylene adipate terephthalate, polybutylene succinate, and polycaprolactone.

3. The ecologically controlled carbon source according to claim 1, characterized in that, The porous mineral material includes at least one of diatomaceous earth, bentonite, zeolite powder, or biochar.

4. The ecologically slow-release carbon source according to claim 1, characterized in that, The water-soluble polysaccharide includes one or more of maltodextrin, soluble starch, and β-cyclodextrin.

5. The ecologically slow-release carbon source according to claim 1, characterized in that, The water-soluble polymer includes one or more of polyvinyl alcohol, polyethylene glycol, and hydroxypropyl methylcellulose.

6. The ecologically slow-release carbon source according to claim 5, characterized in that, The water-soluble polymer is polyethylene glycol with a molecular weight of 1000 to 6000.

7. The ecologically slow-release carbon source according to claim 1, characterized in that, The ecological slow-release carbon source also includes an auxiliary foaming agent.

8. The ecologically slow-release carbon source according to claim 7, characterized in that, The auxiliary foaming agent is ammonium bicarbonate or citric acid.

9. An ecologically slow-release carbon source as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Heat the beeswax to 80-85℃ until it is completely melted. Then, under the condition of heat preservation and shearing stirring, add biodegradable elastomer, water-soluble polymer, water-soluble polysaccharide and porous mineral material in sequence. Shear and stir evenly to obtain a viscous slurry. S2. Pour the viscous slurry into a mold at 50-60℃ and cure the mold as follows: First, heat to 75-85℃ and hold for 10-30 minutes. Second, cool down to 25-35℃ at a rate of 2-5℃ / min and hold for 2-4 hours to complete the curing and molding process, and obtain the initial carbon source. S3. Demold the primary carbon source, soak it in deionized water for 12-48 hours, and then dry it at 40-50°C to constant weight to obtain an ecologically slow-release carbon source.

10. The ecologically controlled carbon source according to claim 9, characterized in that, In step S1, the biodegradable elastomer is pre-cut into particles with a diameter ≤ 5 mm.

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