Mixed mineral material and method for promoting long-term storage of sediment organic carbon

Abstract

The invention discloses a mixed mineral material and method for promoting long-term storage of sediment organic carbon, the material is composed of serpentine and magnesite according to a certain proportion, and the method comprises the following steps: 1) selecting mineral materials serpentine and magnesite as raw materials; (2) pretreating the serpentine and the magnesite; 3) uniformly mixing the pretreated serpentine and magnesite according to a certain proportion; 4) spreading the mixed mineral material on the surface of the sediment by a certain thickness; and 5) reacting the mixed mineral material with the sediment organic carbon to generate a stable magnesium carbonate mineral so as to realize in-situ long-term storage of the sediment organic carbon. The mineral material has the characteristics of environment friendliness, reasonable formula, convenience in use, ecological environment friendliness and the like. According to the method, in-situ long-term sequestration of the sediment organic carbon is realized through reaction of the mixed mineral material and the organic carbon, and a new thought is provided for assisting carbon neutralization and realizing in-situ carbon sequestration of the sediment in water ecological restoration engineering.

Description

Technical Field

[0001] The present invention belongs to the technical field of water ecological restoration and carbon emission reduction, and more specifically relates to a mixed mineral material. It also relates to a method for promoting the long-term storage of organic carbon in sediments, which can be applied to ecological restoration projects of polluted water bodies. Background Art

[0002] Aquatic ecosystems are a significant global source of greenhouse gases. The continued eutrophication of freshwater ecosystems worldwide will lead to increased greenhouse gas emissions from lakes. Lakes generally have a higher carbon cycle intensity than terrestrial units such as grasslands and forests, playing a crucial role in the global carbon cycle. Globally, lakes emit approximately 110-570 billion tons of CO2 into the atmosphere annually, making them a significant carbon source.

[0003] Sediments are the primary site of organic matter mineralization. Lake sediments are important sites of carbon accumulation and a crucial source of nutrients and activity for lake ecosystems. The state of sediments significantly influences the production and emission of greenhouse gases from lakes. Since 1850, nutrient levels in Chinese lakes have increased rapidly, with average concentrations of nitrogen and phosphorus in sediments increasing by 267% and 202%, respectively. The release of endogenous pollution will lead to elevated levels of nutrients such as nitrogen and phosphorus in inland waters, causing eutrophication and deteriorating water quality, and is expected to further exacerbate greenhouse gas emissions from aquatic systems. Greenhouse gases from aquatic ecosystems are primarily emitted into the atmosphere through the sediment-water-atmosphere system. Dissolved organic matter in sediments is one of the largest active carbon reservoirs on Earth, and the fate of organic matter in sediments plays a crucial role in greenhouse gas production. The effective and long-term sequestration of organic carbon in sediments has become a major challenge facing China's aquatic ecological management and restoration efforts under the "dual carbon" goals.

[0004] Currently, there are ongoing research and successful cases promoting the sequestration of organic carbon in sediments. Organic carbon bound by activated iron oxides can fix carbon to a certain extent, but it is unstable and microbial activity can accelerate its decomposition. The main technical difficulty lies in the difficulty of efficiently and stably storing organic carbon in sediments. Summary of the Invention

[0005] The purpose of the present invention is to address the technical difficulty of how to effectively and long-term seal organic carbon in sediments, and to provide a mixed mineral material that promotes the long-term sealing of organic carbon in sediments. The mineral material in the present invention is environmentally friendly, has a reasonable formula, is easy to use, is eco-friendly, and has significant effects.

[0006] Another object of the present invention is to provide a method for promoting the long-term sequestration of organic carbon in sediments. This method is easy to implement, simple to operate, and has significant environmental benefits. By reacting a mixed mineral material with organic carbon, the present invention achieves long-term in-situ sequestration of organic carbon in sediments, providing technical support for achieving carbon neutrality in aquatic ecological restoration projects and achieving in-situ carbon sequestration in sediments.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0008] The present invention aims to achieve long-term in-situ storage of organic carbon in sediments by reacting mixed mineral materials with organic carbon, providing a new approach to assist carbon neutrality in water ecological restoration projects and achieve in-situ carbon sequestration in sediments.

[0009] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fractions:

[0010] raw material%

[0011] Serpentine 70-90

[0012] Magnesite 10-30.

[0013] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fraction (preferred range):

[0014] raw material%

[0015] Serpentine 75-90

[0016] Magnesite 10-25.

[0017] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fraction (preferably within a certain range):

[0018] raw material%

[0019] Serpentine 78-85

[0020] Magnesite 15-22.

[0021] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fractions (optimal range):

[0022] raw material%

[0023] Serpentine 79-82

[0024] Magnesite 18-21.

[0025] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fractions (optimum values):

[0026] raw material%

[0027] Serpentine 80

[0028] Magnesite 20.

[0029] Serpentine is a hydrous magnesium-rich silicate mineral primarily composed of magnesium oxide and silicon dioxide. It has a Mohs hardness ranging from 2.5 to 4 and originates from igneous rocks. Serpentine minerals have broad application prospects due to their heat resistance, corrosion resistance, wear resistance, heat and sound insulation, excellent processing properties, and associated beneficial components. China has abundant serpentine resources of high quality. Major mining areas include Shanzuokou in Donghai County, Jiangsu Province; Zhangshudun in Yiyang, Jiangxi Province; Wohu in Xinyang, Henan Province; Heimulin in Ningqiang County, Shaanxi Province; Jianchaling in Lueyang County; and Anzishan in Mian County.

[0030] Magnesite is a trigonal carbonate mineral, typically present as granular or cryptocrystalline, dense blocks. Magnesite is primarily composed of magnesium carbonate, often with iron and manganese replacing magnesium. It has a Mohs hardness of 3.5-4.5 and a specific gravity of 2.9-3.1. It is primarily used in refractory materials, building materials, chemical raw materials, and for the extraction of metallic magnesium and magnesium compounds.

[0031] The applicant has previously conducted research on using mineral materials to improve substrate microecology and control endogenous pollution, but there are no reports on mineral materials promoting the long-term sequestration of organic carbon in sediments. Through extensive research and experimental demonstration, the present invention, for the first time, combines the two aforementioned materials in a specific ratio to create a mixed mineral material, which is then applied to promote the sequestration and remediation of organic carbon in lake sediments.

[0032] The most critical of the two materials is serpentine, a hydrous magnesium-rich silicate mineral that can fix CO2 and dissolved organic carbon into stable carbonate minerals through thermodynamically favorable alteration processes.

[0033] The optimal ratio of serpentine and magnesite was determined through extensive experimental research and engineering applications. Magnesite, a magnesium-containing carbonate mineral, belongs to the trigonal crystal system, with single crystals forming rhombohedral shapes and aggregates forming macrocrystalline or cryptocrystalline, dense blocks. Therefore, the present invention combines these two materials in a proportional manner, leveraging their characteristics and advantages to prepare a mixed mineral material. This mixed mineral material reacts with organic carbon to achieve long-term in-situ storage of organic carbon in sediments, providing a new approach for achieving carbon neutrality and in-situ carbon sequestration in sediments in water ecological restoration projects.

[0034] A method for promoting long-term sequestration of organic carbon in sediments, comprising the steps of:

[0035] 1) Soak a certain proportion of serpentine in 2-5% dilute hydrochloric acid for 1-2 hours, then wash with clean water until neutral and set aside;

[0036] 2) Soak a certain proportion of magnesite in 1-2% dilute hydrochloric acid for 1-2 hours, then wash with clean water until neutral and set aside;

[0037] 3) uniformly mixing the pretreated serpentine and magnesite according to a certain mass fraction to prepare a mixed mineral material;

[0038] 4) Spreading the mixed mineral material to a certain thickness (1-2 cm) on the sediment surface;

[0039] 5) By mixing mineral materials and reacting with sediment organic carbon, long-term in-situ storage of sediment organic carbon can be achieved.

[0040] Through the above-mentioned technical measures: the most critical thing is to mix the pretreated serpentine and magnesite evenly according to a certain mass fraction to prepare a mixed mineral material, which mainly solves the technical difficulties of long-term and effective storage of organic carbon in sediments, and provides a new idea for water ecological restoration projects to help carbon neutrality and realize in-situ carbon storage of sediments. Through the entire technical measure, more than 60% of the organic carbon in the surface layer of sediments (0-10 cm) is converted into stable magnesium carbonate minerals. The applicant's research team previously studied that the combination of silicate minerals and submerged plants can reduce greenhouse gas emissions to a certain extent, but cannot effectively store carbon. The progress of its invention over the prior art is mainly reflected in the discovery for the first time that mixing serpentine and magnesite to prepare a mixed mineral material can efficiently and long-term seal organic carbon in sediments, effectively solving the major technical problems facing China's water ecological governance and restoration under the "dual carbon" goal.

[0041] Compared with the prior art, the present invention has the following advantages and effects:

[0042] 1. The method is easy to implement and operate, and has significant environmental and social benefits;

[0043] 2. The mixed mineral materials are all composed of natural minerals, which are environmentally friendly and have no secondary pollution;

[0044] 3. By giving full play to the characteristics of natural materials, it can significantly promote the long-term effective storage of organic carbon in sediments. Compared with the control group, more than 60% of the organic carbon in the surface layer of sediments (0-10 cm) was converted into stable magnesium carbonate minerals after 2 months of implementation. DETAILED DESCRIPTION

[0045] In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

[0046] Example 1:

[0047] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fractions:

[0048] raw material%

[0049] Serpentine 71

[0050] Magnesite 29.

[0051] A method for promoting long-term sequestration of organic carbon in sediments, comprising the steps of:

[0052] 1) Soak a certain proportion of serpentine in 2% dilute hydrochloric acid for 1 hour, then wash with clean water until neutral and set aside;

[0053] 2) Soak a certain proportion of magnesite in 1% dilute hydrochloric acid for 1 hour, then wash with clean water until neutral and set aside;

[0054] 3) uniformly mixing the pretreated serpentine and magnesite according to the above mass fractions to prepare a mixed mineral material;

[0055] 4) Spread the mixed mineral material on the sediment surface to a thickness of 1 cm;

[0056] 5) By mixing mineral materials and reacting with sediment organic carbon, long-term in-situ storage of sediment organic carbon can be achieved.

[0057] After a period of implementation, the proportion (%) of organic carbon in the surface layer of sediment (0-10 cm) converted into stable carbon is shown in Table 1, where the organic carbon in Example 1 is converted into stable magnesium carbonate minerals.

[0058] Table 1 Example 1 Conversion ratio of organic carbon to stable carbon

[0059]

[0060] Example 2:

[0061] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fractions:

[0062] raw material%

[0063] Serpentine 80

[0064] Magnesite 20.

[0065] A method for promoting long-term sequestration of organic carbon in sediments, comprising the steps of:

[0066] 1) Soak a certain proportion of serpentine in 5% dilute hydrochloric acid for 2 hours, then wash with clean water until neutral and set aside;

[0067] 2) Soak a certain proportion of magnesite in 2% dilute hydrochloric acid for 2 hours, then wash with clean water until neutral and set aside;

[0068] 3) uniformly mixing the pretreated serpentine and magnesite according to the above mass fractions to prepare a mixed mineral material;

[0069] 4) Spread the mixed mineral material on the sediment surface to a thickness of 2 cm;

[0070] 5) Realize in-situ long-term storage of sediment organic carbon by reacting mixed mineral materials with sediment organic carbon;

[0071] After a period of implementation, the proportion (%) of organic carbon in the surface layer of sediment (0-10 cm) converted into stable carbon is shown in Table 2, where the organic carbon in Example 2 is converted into stable magnesium carbonate minerals.

[0072] Table 2 Example 2 Conversion of organic carbon into stable carbon ratio

[0073]

[0074]

[0075] Example 3:

[0076] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fractions:

[0077] raw material%

[0078] Serpentine 89

[0079] Magnesite 11

[0080] The preparation steps are the same as those in Example 1.

[0081] After a period of implementation, the proportion (%) of organic carbon in the surface layer of sediment (0-10 cm) converted into stable carbon is shown in Table 3, where the organic carbon in Example 3 is converted into stable magnesium carbonate minerals.

[0082] Table 3 Example 3 Conversion of organic carbon into stable carbon ratio

[0083]

[0084] Example 4:

[0085] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fractions:

[0086] raw material%

[0087] Serpentine 85

[0088] Magnesite 15

[0089] The preparation steps are the same as those in Example 2.

[0090] After a period of implementation, the proportion (%) of organic carbon in the surface layer of sediment (0-10 cm) converted into stable carbon is shown in Table 4, where the organic carbon in Example 4 is converted into stable magnesium carbonate minerals.

[0091] Table 4: Ratio of organic carbon converted to stable carbon in Example 4

[0092]

[0093] Example 5

[0094] A mixed mineral material for promoting long-term storage of organic carbon in sediments, which is made of the following raw materials in mass fractions:

[0095] raw material%

[0096] Serpentine 82

[0097] Magnesite 18

[0098] The preparation steps are the same as those in Example 1 or 2.

[0099] After a period of implementation, the proportion (%) of organic carbon in the surface layer of sediment (0-10 cm) converted into stable carbon is shown in Table 5, where the organic carbon in Example 5 is converted into stable magnesium carbonate minerals.

[0100] Table 5: Ratio of organic carbon converted to stable carbon in Example 5

[0101]

[0102] For the first time, it was discovered that mixing serpentine and magnesite into a mixed mineral material can efficiently and long-term seal the organic carbon in sediments, effectively solving the major technical difficulties facing China's water ecological governance and restoration under the "dual carbon" goals.

Claims

1. A mixed mineral material for promoting long-term storage of organic carbon in sediments, comprising the following raw materials in the following mass fractions: raw material% Serpentine 70-90 Magnesite 10-30.

2. The mixed mineral material for promoting long-term storage of organic carbon in sediments according to claim 1, characterized in that: raw material% Serpentine 75-90 Magnesite 10-25.

3. The mixed mineral material for promoting long-term storage of organic carbon in sediments according to claim 1, characterized in that: raw material% Serpentine 78-85 Magnesite 15-22.

4. The mixed mineral material for promoting long-term storage of organic carbon in sediments according to claim 1, characterized in that: raw material% Serpentine 79-82 Magnesite 18-21.

5. The mixed mineral material for promoting long-term storage of organic carbon in sediments according to claim 1, characterized in that: raw material% Serpentine 80 Magnesite 20.

6. The method for promoting long-term storage of organic carbon in sediments according to claim 1, comprising the steps of: 1) Soak a certain proportion of serpentine in 2-5% dilute hydrochloric acid for 1-2 hours, then wash with clean water until neutral and set aside; 2) Soak a certain proportion of magnesite in 1-2% dilute hydrochloric acid for 1-2 hours, then wash with clean water until neutral and set aside; 3) uniformly mixing the pretreated serpentine and magnesite according to a certain mass fraction to prepare a mixed mineral material; 4) Spreading a certain thickness of the mixed mineral material on the sediment surface; 5) By mixing mineral materials and reacting with sediment organic carbon, long-term in-situ storage of sediment organic carbon can be achieved.

7. The method for promoting long-term storage of organic carbon in sediments according to claim 6, characterized in that: The mixed mineral material is spread on the sediment surface with a thickness of 1-2 cm.

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