Reinforcement method based on basalt carbon sequestration and application thereof

Abstract

The application discloses a method for strengthening basalt carbon sequestration and application thereof, and belongs to the field of novel carbon sequestration technology. The application introduces a mixture of pyrolytic carbon and hydrothermal carbon to treat basalt particles, utilizes the characteristics of abundant pore structure and oxygen-containing functional groups of biochar, especially the role of the biochar as an electron donor, promotes the reduction and conversion of Fe (III) on the surface of basalt to Fe (II), thereby effectively inhibiting or destroying the iron-based passivation layer which hinders the weathering reaction; meanwhile, the local supersaturation is reduced by adsorbing and chelating Ca 2+ , Mg 2+ and the like, so that the dissolution reaction is continuously driven. Experiments show that the method can significantly improve the corrosion current density and dissolution rate of basalt in water phase, and greatly enhance the carbon capture and storage capacity of carbon dioxide in air. The application has the advantages of low cost, environmental friendliness, significant carbon sequestration and efficiency enhancement, and is suitable for farmland soil improvement and large-scale rock weathering carbon sequestration engineering.

Description

Technical Field

[0001] This invention belongs to the field of novel carbon fixation technology, specifically involving the application of biochar to accelerate the removal of carbon dioxide from the air by basalt. Background Technology

[0002] With the intensification of global climate change, carbon dioxide (CO2) removal technologies have become one of the important ways to achieve the goals of the Paris Agreement. Enhanced rock weathering technology has attracted much attention due to its huge theoretical carbon sequestration potential and environmental synergistic benefits. This technology artificially accelerates the natural weathering reaction between silicate minerals (such as basalt) and atmospheric CO2 by crushing and applying them to the Earth's surface. During the reaction, the dissolved minerals release Ca2+. 2+ Mg 2+ Alkali metal cations combine with dissolved CO2 to eventually form stable carbonate minerals or dissolved bicarbonates, thus achieving long-term carbon sequestration.

[0003] Although enhanced weathering technology holds great potential for carbon sequestration, existing technologies, especially those based on basalt systems, face a series of key scientific challenges and technological bottlenecks in large-scale practical applications, severely limiting their carbon sequestration efficiency and economic feasibility. Firstly, the weathering and dissolution of silicate minerals is a heterogeneous interfacial reaction. Initially, the dissolution rate on the mineral surface is rapid, but as dissolution progresses, the released cations (such as Ca) increase in concentration. 2+ Mg 2+ Fe 2+ / Fe 3+ It is easy for carbonate precipitates or iron (oxy) hydroxide coatings to form in situ on the surface of mineral particles. This passivation layer physically blocks the reactants (H2O, CO2, H2O) from reacting. + The contact between basalt and fresh mineral surfaces significantly inhibits the further migration of ions from the mineral lattice, leading to a sharp decrease in the weathering rate over time, resulting in an unsustainable carbon fixation process and incomplete dissolution of silicate minerals. Secondly, while basalt is a preferred material for enhancing weathering due to its abundant reserves and low environmental risk, its mineral composition contains iron-rich phases (such as pyroxene and olivine). During weathering, Fe... 2+ The release of Fe is an inherent characteristic. However, under near-surface oxidation conditions, Fe 2+It will rapidly oxidize and hydrolyze to form amorphous or crystalline iron oxide / hydroxide precipitates. These precipitates not only constitute a dense passivation layer themselves, but also easily intertwine with the aforementioned carbonate precipitates to form a more stubborn composite passivation layer, further exacerbating reaction kinetic hindrance and significantly weakening its long-term carbon sequestration potential. Furthermore, to overcome the passivation problem and improve the initial dissolution rate, existing research has attempted to introduce chemical additives, such as organic chelating agents like amino acids (e.g., oxalic acid, citric acid). These substances can delay passivation layer formation and improve mineral dissolution rates by complexing metal ions and reducing their local supersaturation. However, this method not only introduces costly chelating agents, but excessive use may also lead to soil nutrient loss, hindering large-scale implementation.

[0004] Therefore, there is an urgent need to provide a low-cost, environmentally friendly control method that can effectively suppress the formation of passivation layers in order to achieve continuous dissolution of silicate minerals such as basalt and more efficient carbon dioxide removal. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method for enhancing carbon fixation based on basalt and its application. By adding a mixture of hydrothermal carbon and pyrolytic carbon to basalt particles and mixing them uniformly, a basalt-based enhanced weathering material is obtained. The basalt-based enhanced weathering material prepared by the present invention helps to improve the formation of a passivation layer during the weathering process of basalt, thereby enhancing the carbon fixation effect.

[0006] To achieve the above objectives, the present invention first provides a basalt-based enhanced weathering material, which is composed of basalt particles and composite biochar, wherein the composite biochar is composed of pyrolytic biochar and hydrothermal biochar.

[0007] In one embodiment of the present invention, the mass ratio of the pyrolytic char to the hydrothermal char is 1:9 to 9:1, preferably 1:3 to 3:1.

[0008] In one embodiment of the present invention, the mass ratio of the basalt particles to the composite biochar is 1:10 to 10:1, preferably 1:5 to 5:1, and more preferably 1:1.

[0009] The present invention also provides a method for preparing a basalt-based reinforced weathering material, wherein a composite biochar of pyrolytic carbon and hydrolytic carbon is added to basalt particles and mixed evenly to obtain a basalt-based reinforced weathering material.

[0010] This invention also provides a method for enhanced weathering based on basalt, comprising the following steps: (1) Disperse basalt particles in water to form a basalt particle dispersion; (2) Subsequently, a composite biochar of pyrolytic carbon and hydrolytic carbon was added to the basalt particle dispersion, mixed well, and then subjected to weathering reaction.

[0011] In one embodiment of the present invention, the basalt particles are silicate particles ground by a ball mill, and the average particle size of the basalt particles ranges from 20 to 90 μm, preferably from 30 to 60 μm.

[0012] In one embodiment of the present invention, the concentration of the basalt particle solution in step (1) is 2~20 g / L, preferably 3~10 g / L, more preferably 3~8 g / L, and most preferably 4 g / L.

[0013] In one embodiment of the present invention, in step (2), after adding the composite biochar, the mass concentration of the composite biochar in the dispersion is 2~20 g / L, preferably 3~10 g / L, more preferably 3~8 g / L, and most preferably 4 g / L.

[0014] In one embodiment of the present invention, in step (2), it is preferable to use a shaker to thoroughly mix the ingredients. The shaker conditions are 150-200 rpm and the mixing time is 0-55 days.

[0015] In one embodiment of the present invention, the drying method in step (2) includes at least one of hot air drying, vacuum drying, and freeze drying, wherein the temperature of the hot air drying is 50~80°C and the time is 10~15 hours.

[0016] The present invention also discloses an enhanced method for carbon fixation based on basalt, the enhanced method comprising adding a composite biochar of pyrolytic carbon and hydrolytic carbon to basalt particles, and using the material obtained after uniform mixing for carbon fixation.

[0017] In one embodiment of the present invention, the strengthening method includes adding a composite biochar of pyrolytic carbon and hydrolytic carbon to a dispersion of basalt particles, and using the mixed dispersion to fix carbon.

[0018] In one embodiment of the present invention, the method for preparing the pyrolytic char includes: preparing pyrolytic char by carbonizing biochar raw material by purging it with nitrogen gas at 400~600 ℃.

[0019] In one embodiment of the present invention, during the preparation of pyrolytic char, pulverized biochar raw material is placed in a reactor and heated to 400-600°C at a heating rate of 5-15°C / min under a nitrogen atmosphere, and maintained at the target temperature for 2-3 hours.

[0020] In one embodiment of the present invention, the method for preparing the hydrothermal char includes: placing biochar raw material in a hydrothermal reactor for hydrothermal synthesis to obtain hydrolyzed char.

[0021] In one embodiment of the present invention, the biochar raw material may be selected from at least one of crop straws such as corn stalks, rice stalks, and wheat stalks.

[0022] In one embodiment of the present invention, the solid-liquid mass ratio of the hydrothermal carbon is 1:5~10. The slurry is stirred and heated to 300 °C, and then immediately cooled to room temperature. The generated hydrothermal carbon is collected by filtration and centrifugation, and then dried at room temperature.

[0023] The present invention also provides an application of basalt-based enhanced weathering material in farmland carbon sequestration: the basalt-based enhanced weathering material is manually sprinkled into the farmland at an addition rate of 2-6% and 20-60 t / ha, and then the basalt is uniformly mixed with the soil by traditional plowing.

[0024] Beneficial effects: (1) This invention combines hydrothermal carbon with pyrolytic carbon, and then mixes the composite biochar into basalt particles. The biochar in the system can act as an electron donor, promoting the reduction and transformation of Fe(III) to Fe(II) on the basalt surface, and significantly reducing the content of high-valence iron oxides in the passivation layer. Electrochemical test results show that the mixed carbon treatment reduces the charge transfer resistance (R0) to 100%. t ) and passivation film resistance (R f The significant reduction in [a certain percentage] confirms that the passivation layer was effectively weakened, thereby continuously exposing the fresh mineral surface and avoiding reaction stagnation caused by surface covering. In contrast, neither pyrolytic carbon nor hydrothermal carbon systems can achieve the same degree of passivation layer damage.

[0025] (2) The mixed biochar of the present invention, with its abundant oxygen-containing functional groups (-COOH, -OH, etc.) and porous structure, can efficiently complex Ca released by weathering. 2+ Mg 2+ Fe 2+ Metal ions, etc. ICP-MS analysis showed that it had a significant effect on Ca. 2+ Mg 2+ Fe 2+ The adsorption capacities were increased by 62.7%, 197.4%, and 50.4% respectively compared to the basalt system alone. This effect reduces the ion concentration in the solution, promoting the continued positive weathering reaction; on the other hand, it avoids Ca... 2+ Mg 2+ Fe 2+ These substances precipitate on the basalt surface to form a carbonate or iron (oxy) hydroxide coating, thereby maintaining the surface reactivity.

[0026] (3) The mixed carbon system of the present invention combines the functional groups of hydrothermal carbon with the high conductivity of pyrolytic carbon to construct an efficient electron transport channel at the solid-liquid interface. Polarization curves show that the corrosion current density is increased by 49%, and the dissolution rate is reduced from 7.39 × 10⁻⁶. -7 mol·m -2 ·s -1 Increased to 1.10×10 -6 mol·m -2 ·s -1 This indicates that the charge transfer step of the weathering reaction is significantly accelerated, and the overall reaction kinetics are enhanced.

[0027] (4) The addition of composite biochar in this invention increases CO2 fixation efficiency by about 2.5 times, and reduces the time required for 50% of basalt particles to dissolve to 27% of that of pure basalt system. In farmland application simulation (40 t / ha), the addition of composite biochar can achieve a cumulative CO2 fixation of about 4.97 Gt within 10 years. The time required to achieve the same carbon fixation effect is reduced by about 41% compared with basalt alone (from 17 years to 10 years), demonstrating outstanding environmental application value and economic benefits.

[0028] (5) This invention creatively constructs a composite synergistic system of rigid framework of pyrolytic carbon and chemical activity of hydrothermal carbon. On the one hand, the macroporous structure of pyrolytic carbon is used to achieve high dispersion loading of hydrothermal carbon, preventing its agglomeration and loss. On the other hand, the continuously released soluble organic ligands (DOM) of hydrothermal carbon are used to clean and peel off the passivation layer on the surface of pyrolytic carbon and basalt in real time through efficient complexation. This dual synergistic mechanism of physical support and chemical self-cleaning successfully maintains a low-resistance active interface over a long period of time, thereby achieving an unexpected technical effect in which the cumulative carbon fixation is significantly better than the simple sum of the two. Attached Figure Description

[0029] Figure 1 SEM images of basalt before and after weathering; Figure 2 XRD images of basalt before and after weathering; Figure 3 The surface elemental distribution of basalt and basalt + biochar after unweathered and 30 days of weathering; Figure 4 Trends of Ca, Mg, Si concentrations, pH, alkalinity, and TIC over time; Figure 5 Electrochemical polarization curves, EIS impedance spectroscopy results, and elemental variations on mineral surfaces Figure 6 Calculation and model prediction of carbon dioxide fixation. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments.

[0031] The embodiments provided below are not intended to limit the scope of this invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to this invention by those skilled in the art in conjunction with existing common knowledge also fall within the scope of protection claimed by this invention.

[0032] Example 1 A basalt-based enhanced weathering material is disclosed, comprising basalt particles and composite biochar in a mass ratio of 1:1. The composite biochar is composed of pyrolytic char and hydrothermal char in a mass ratio of 1:1.

[0033] A method for preparing basalt-based reinforced weathering materials involves mixing pyrolytic carbon and hydrothermal carbon at a mass ratio of 1:1 to obtain composite biochar, and then mixing the composite biochar with basalt particles at a mass ratio of 1:1.

[0034] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (4) Preparation of composite biochar: The pyrolytic carbon in step (1) and the hydrothermal carbon in step (2) are mixed at a mass ratio of 1:1 to form composite biochar for enhancing weathering.

[0035] (5) Preparation of basalt-based reinforced weathering material: Weigh 0.12 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 0.4%. Place the mixture in a 40 mL glass bottle and add 0.12 g of the composite biochar obtained in step (4). Mix thoroughly using a shaker at 25 °C with a shaker speed of 150 rpm. Then conduct a weathering experiment for 0 to 55 days. Example 2 The difference between Example 2 and Example 1 is that the composite ratio of pyrolytic carbon and hydrothermal carbon is changed to 1:3.

[0036] A method for preparing basalt-based reinforced weathering materials involves mixing pyrolytic carbon and hydrothermal carbon at a mass ratio of 1:3 to obtain composite biochar, and then mixing the composite biochar with basalt particles at a mass ratio of 1:1.

[0037] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (4) Preparation of composite biochar: The pyrolytic carbon in step (1) and the hydrothermal carbon in step (2) are mixed at a mass ratio of 1:3 to form composite biochar for enhancing weathering.

[0038] (5) Preparation of basalt-based reinforced weathering material: Weigh 0.12 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 0.4%. Place the mixture in a 40 mL glass bottle and add 0.12 g of the composite biochar obtained in step (4). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction.

[0039] Example 3 The difference between Example 3 and Example 1 is that the composite ratio of pyrolytic carbon and hydrothermal carbon is changed to 3:1.

[0040] A method for preparing basalt-based reinforced weathering materials involves mixing pyrolytic carbon and hydrothermal carbon at a mass ratio of 3:1 to obtain composite biochar, and then mixing the composite biochar with basalt particles at a mass ratio of 1:1.

[0041] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (4) Preparation of composite biochar: The pyrolytic carbon in step (1) and the hydrothermal carbon in step (2) are mixed at a mass ratio of 3:1 to form composite biochar for enhancing weathering.

[0042] (5) Preparation of basalt-based reinforced weathering material: Weigh 0.12 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 0.4%. Place the mixture in a 40 mL glass bottle and add 0.12 g of the composite biochar obtained in step (4). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction. Example 4 The difference between Example 4 and Example 1 is that the ratio of composite biochar (pyrolytic carbon and hydrothermal carbon) to basalt is changed to 1:3.

[0043] A method for preparing basalt-based enhanced weathering materials involves mixing pyrolytic carbon and hydrothermal carbon at a mass ratio of 1:1 to obtain composite biochar, and then mixing the composite biochar with basalt particles at a mass ratio of 1:3.

[0044] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (4) Preparation of composite biochar: The pyrolytic carbon in step (1) and the hydrothermal carbon in step (2) are mixed at a mass ratio of 1:1 to form composite biochar for enhancing weathering.

[0045] (5) Preparation of basalt-based reinforced weathering material: Weigh 0.36 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 1.2%. Place the mixture in a 40 mL glass bottle and add 0.12 g of the composite biochar obtained in step (4). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction. Example 5 The difference between Example 5 and Example 1 is that the ratio of composite biochar (pyrolytic carbon and hydrothermal carbon) to basalt is changed to 2:1.

[0046] A method for preparing basalt-based reinforced weathering materials involves mixing pyrolytic carbon and hydrothermal carbon at a mass ratio of 1:1 to obtain composite biochar, and then mixing the composite biochar with basalt particles at a mass ratio of 2:1.

[0047] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (4) Preparation of composite biochar: The pyrolytic carbon in step (1) and the hydrothermal carbon in step (2) are mixed at a mass ratio of 1:1 to form composite biochar for enhancing weathering.

[0048] (5) Preparation of basalt-based reinforced weathering material: Weigh 0.12 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 0.4%. Place the mixture in a 40 mL glass bottle and add 0.24 g of the composite biochar obtained in step (4). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction.

[0049] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that steps (2) to (5) are omitted.

[0050] A method for preparing basalt particles: basalt blocks are ground using a ball mill to obtain basalt particles with an average particle size of approximately 50 μm.

[0051] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that steps (3) and (4) are omitted, and the pyrolytic carbon in step (2) and the basalt particles in step (1) are directly mixed.

[0052] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of basalt-based reinforced weathering material: Weigh 0.12 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 0.4%. Place the mixture in a 40 mL glass bottle and add 0.12 g of pyrolytic carbon obtained in step (2). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction.

[0053] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that steps (2) and (4) are omitted, and the hydrothermal carbon in step (3) and the basalt particles in step (1) are directly mixed.

[0054] A method for preparing basalt-based reinforced weathering materials involves mixing hydrothermal carbon and basalt particles at a mass ratio of 1:1.

[0055] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (3) Preparation of basalt-based reinforced weathering material: Weigh 0.12 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 0.4%. Place the mixture in a 40 mL glass bottle and add 0.12 g of hydrothermal carbon obtained in step (2). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction. Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the composite ratio of pyrolytic carbon and hydrothermal carbon is changed to 4:1.

[0056] A method for preparing basalt-based reinforced weathering materials involves mixing pyrolytic carbon and hydrothermal carbon at a mass ratio of 4:1 to obtain composite biochar, and then mixing the composite biochar with basalt particles at a mass ratio of 1:1.

[0057] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (4) Preparation of composite biochar: The pyrolytic carbon in step (1) and the hydrothermal carbon in step (2) are mixed at a mass ratio of 4:1 to form composite biochar for enhancing weathering.

[0058] (5) Preparation of basalt-based reinforced weathering material: Weigh 0.12 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 0.4%. Place the mixture in a 40 mL glass bottle and add 0.12 g of the composite biochar obtained in step (4). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction. Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the composite ratio of pyrolytic carbon and hydrothermal carbon was changed to 1:7.

[0059] A method for preparing basalt-based reinforced weathering materials involves mixing pyrolytic carbon and hydrothermal carbon at a mass ratio of 1:7 to obtain composite biochar, and then mixing the composite biochar with basalt particles at a mass ratio of 1:1.

[0060] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (4) Preparation of composite biochar: The pyrolytic carbon in step (1) and the hydrothermal carbon in step (2) are mixed at a mass ratio of 1:7 to form composite biochar for enhancing weathering.

[0061] (5) Preparation of basalt-based reinforced weathering material: Weigh 0.12 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 0.4%. Place the mixture in a 40 mL glass bottle and add 0.12 g of the composite biochar obtained in step (4). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction. Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that the ratio of composite biochar (pyrolytic carbon and hydrothermal carbon) to basalt was changed to 6:1.

[0062] A method for preparing basalt-based reinforced weathering materials involves mixing pyrolytic carbon and hydrothermal carbon at a mass ratio of 1:1 to obtain composite biochar, and then mixing the composite biochar with basalt particles at a mass ratio of 6:1.

[0063] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (4) Preparation of composite biochar: The pyrolytic carbon in step (1) and the hydrothermal carbon in step (2) are mixed at a mass ratio of 1:1 to form composite biochar for enhancing weathering.

[0064] (5) Preparation of basalt-based reinforced weathering material: Weigh 0.12 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 0.4%. Place the mixture in a 40 mL glass bottle and add 0.72 g of the composite biochar obtained in step (4). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction. Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that the ratio of composite biochar (pyrolytic carbon and hydrothermal carbon) to basalt was changed to 1:5.

[0065] A method for preparing basalt-based reinforced weathering materials involves mixing pyrolytic carbon and hydrothermal carbon at a mass ratio of 1:1 to obtain composite biochar, and then mixing the composite biochar with basalt particles at a mass ratio of 1:5.

[0066] A basalt-based method for enhanced weathering includes the following steps: (1) Preparation of basalt particles: Basalt blocks were ground by ball milling to obtain basalt particles with an average particle size of about 50 μm; (2) Preparation of pyrolytic char: Corn stalks were placed in a carbonization furnace and carbonized at 500 °C for 2 h under a nitrogen atmosphere to obtain pyrolytic char; (3) Preparation of hydrothermal char: Corn stalks and water are mixed at a solid-liquid ratio of 1:7.5. The mixture is placed in a high-pressure hydrothermal reactor. The slurry is stirred and heated to 300 °C. Then it is immediately cooled at room temperature to obtain hydrothermal char. (4) Preparation of composite biochar: The pyrolytic carbon in step (1) and the hydrothermal carbon in step (2) are mixed at a mass ratio of 1:1 to form composite biochar for enhancing weathering.

[0067] (5) Preparation of basalt-based reinforced weathering material: Weigh 0.6 g of basalt particles from step (1) and mix with 30 mL of deionized water. The solid-liquid ratio is 2%. Place the mixture in a 40 mL glass bottle and add 0.12 g of the composite biochar obtained in step (4). Mix thoroughly using a shaker at 25 °C with the shaker speed at 150 rpm. Then carry out the weathering reaction. Basalt characteristics: The basalt blocks were ground using a ball mill to obtain basalt particles with an average diameter of approximately 50 μm. The basalt was then characterized using X-ray fluorescence spectrometry (XRF). Tables 1 and 2 show the main oxides and elemental composition of the basalt, respectively. Table 1 shows that the composition of the basalt is: SiO₂ 54.5%, MgO 15.8%, CaO 12.7%, Fe₂O 39.4%, etc. Its specific surface area, measured by a specific surface area analyzer, is 518.6 m². 2 / kg, the morphology and size of basalt grains were characterized using transmission electron microscopy (TEM). The results showed that the average width of the basalt was 50.9 ± 30.4 μm. Figure 1 ).

[0068] Table 1. Main oxide composition of basalt

[0069] Table 2. Elemental composition of basalt

[0070] Weathering experiment: The basalt particle dispersion and the mixed dispersion of basalt particles and biochar were reacted at 25 ℃ and 150 rpm for 55 days. Samples were taken at 0, 1, 3, 5, 7, 10, 15, 21, 30, 40 and 55 days.

[0071] Passivation layer formation and mechanism analysis Basalt particles with different weathering times were taken out of the aqueous solution, dried at room temperature, and the morphology and elemental distribution of the basalt surface before and after weathering were analyzed using scanning electron microscopy (SEM-EDX).

[0072] This study investigated the weathering effects of basalt particles and basalt and biochar after different weathering times. The initial weathering reaction (0-7 days) reflected the rapid surface ion exchange capacity during the initial contact phase. Intensive sampling (1, 3, 5 days) precisely captured the instantaneous acidification and adsorption effects after biochar addition. During the reaction transition period (10-30 days), a passivation layer of iron hydroxyl oxide forms on the basalt surface, causing the reaction rate to shift from chemically controlled to diffusion-controlled, significantly slowing the overall rate. In the long-term reaction stage (40-55 days), single biochar systems often cease reaction due to pore blockage or depletion of active sites (the curve tends to flatten). This example, by extending observation to 55 days, aims to demonstrate that the mixed carbon system can maintain the acid-base balance and structural stability of the microenvironment, maintaining a high weathering and carbon fixation rate over a long period, thus confirming its sustainable potential in practical environmental applications.

[0073] Thirty days after basalt weathering, the basalt particles were placed on SEM-EDX to observe the basalt-based reinforced weathering material, and X-ray diffraction (GI-XRD) was used to analyze the changes in mineral crystal forms before and after weathering.

[0074] Characterization by SEM-EDX revealed that, for example Figures 1-2 As shown, the surface of unweathered basalt is smooth. Individual basalt particles show pitting on their surface after 30 days of weathering, accompanied by Fe enrichment, indicating the formation of an iron (oxygen) hydride passivation layer. Figure 3 XRD analysis results further confirmed that after 55 days of weathering, low-solubility secondary minerals such as ferrohydrides, calcite, and dolomite appeared on the surface.

[0075] Figure 3XRD analysis results of the basalt-based reinforced weathering material in Example 1 before and after weathering are presented. The results show that the content of other element species such as Fe, Si, and Al in Example 1 changed significantly after weathering, especially the proportion of Fe(II), which increased significantly by 11.3%. Fe-based oxides / hydroxides (Fe(III)) are key components of the basalt surface 'passivation layer' and are also the main 'rate-limiting step' that leads to a significant decrease in the natural weathering rate over time. Promoting the conversion of Fe(III) to Fe(II) through some means helps to promote the dissolution of Fe(III), thereby destroying the surface passivation layer. Figure 3 The results show that the proportion of Fe(II) was significantly increased after the addition of composite biochar, which directly proves that biochar, as an electron donor, successfully drove the reduction and dissolution of Fe, thereby destroying the surface passivation layer.

[0076] For mixtures of single pyrolytic carbon or single hydrothermal carbon with basalt, the addition of single pyrolytic carbon and single hydrothermal carbon also helps to promote changes in element content after weathering, but the proportion of Fe(II) does not increase significantly. This indicates that single pyrolytic carbon or hydrothermal carbon has a weak destructive effect on the passivation layer and is difficult to effectively increase the weathering effect of basalt.

[0077] Electrochemical analysis: 10 mg of basalt particles or basalt-based reinforced weathering material was added to 950 μL of water and ethanol, followed by 50 μL of Nafion solution. The mixture was sonicated for 15 minutes to obtain the sample. 10 μL of the sample was dropped onto a clean glassy carbon electrode and dried at room temperature. A platinum electrode was used as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1 M sodium sulfate. The test mode was LSV mode, the test voltage range was 0–1.6 V, the scan rate was 10 mV / s, and the electrochemical workstation model was CHI760E.

[0078] 10 mg of basalt particles or basalt-based reinforced weathering material was added to 950 μL of water and ethanol, followed by 50 μL of Nafion solution. The mixture was sonicated for 15 minutes to obtain the sample. 10 μL of the sample was dropped onto a clean glassy carbon electrode and dried at room temperature. A platinum electrode was used as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1 M sodium sulfate. The testing mode was EIS mode, with a frequency range of 100 kHz–0.1 Hz, an AC amplitude of 10 mV, and an electrochemical workstation model of CHI 760E.

[0079] Figure 4Tables A and B present the polarization curves and EIS impedance spectra of Example 1 (Ba + water / fire), Comparative Example 1 (Ba), Comparative Example 2 (Ba + fire), and Comparative Example 3 (Ba + water), respectively. Tables 3 and 4 present the electrochemical parameters and equivalent circuit model parameters of basalt in aqueous solution under different biochar treatment conditions. Rs (Ω), the solution resistance, represents the conductivity of the electrolyte solution (water), which is inversely proportional to the ion concentration in the solution; a lower value is better (indicating more dissolved ions and stronger conductivity). Rf (Ω), the passivation film resistance, represents the degree to which the "passivation layer" (such as iron oxide or secondary precipitate) covering the basalt surface hinders ion migration; a lower value is better (indicating the passivation layer is destroyed and the surface is exposed). Rt (Ω), the charge transfer resistance, is the most critical parameter, representing the ease with which electrons / ions cross the solid-liquid interface to undergo chemical reactions (corrosion / weathering). It directly determines the rate of weathering. The smaller the sum of the three resistances, the better.

[0080] Figure 4 The results in Tables 3 and 4 show that biochar increased the corrosion current density of basalt by 49% and reduced the dissolution rate from 7.39 × 10⁻⁶. -7 Increased to 1.10×10 -6 mol / m 2 / s, passivation layer resistance (R) of composite biochar treatment group f ) and charge transfer resistance (R t The significant reduction in electron transport indicates enhanced electron transfer and weakening of the passivation layer.

[0081] C and D represent the elemental changes on the mineral surface after weathering treatment with mixed carbon and basalt, and weathering treatment with basalt alone, respectively. XPS analysis revealed a higher proportion of ferric ions (Fe3+) on the surface of basalt alone. Basalt weathering releases ferrous ions (Fe2+). 2+ In natural aquatic environments, Fe 2+ It is easily oxidized to ferric iron (Fe3+). 3+ Fe 3+ Iron has low solubility and readily precipitates in situ on rock surfaces, forming amorphous or crystalline iron oxides / hydroxides (such as goethite and hematite). This layer clogs pores, sealing the rock inside and halting weathering. The mixed carbon system (Figure C) shows lower Fe content. 3+ Surface percentage analysis confirms that the dissolved organic ligands (DOM) released by biochar effectively complex iron ions at the interface, transferring them from the solid surface to the liquid phase, thereby preventing the deposition and coverage of secondary iron minerals on the surface. This is achieved by reducing inactive Fe... 3+ The oxide layer covering the basalt surface successfully maintains its "fresh" state, ensuring that the active dissolution sites are continuously exposed to the aqueous solution, thereby achieving long-term enhanced carbon fixation.

[0082] For basalt weathered materials reinforced with single pyrolytic carbon or hydrothermal carbon, while the corrosion current density and dissolution rate are also improved, the increase is very limited. Specifically, for the mixed assemblage of single pyrolytic carbon and basalt, the single high-temperature pyrolytic carbon has a graphitized structure and excellent electrical conductivity. When measuring EIS, if the basalt surface is covered with a layer of conductive carbon, the current will be conducted along the carbon. Therefore, although the R of the single pyrolytic carbon + basalt assemblage is relatively high... f The smaller value only indicates the good electrical conductivity of the carbon, not its small passivation layer. In fact, for pyrolytic carbon, due to its lack of acid attack (R... t (Large), the passivation layer on the surface of basalt is difficult to dissolve.

[0083] Extremely high R values ​​were observed in the isolated basalt formation (control group). f and R t The value indicates that the surface is encased in a dense insulating passivation film, blocking the ion release channels. However, in the mixed carbon group, despite the physical coverage of the biochar layer, its R... t The value decreased compared to the control group. This proves that the passivation layer did not thicken physically, but rather became porous through the "complexation-exfoliation" mechanism of biochar. This electrochemical conclusion is consistent with the Fe values ​​observed in the aforementioned XPS analysis. 3+ The reduced proportion of these substances corroborates each other: the removal of high-valence iron oxides (high-resistance substances) from the surface directly leads to a reduction in the resistance to the electrochemical reaction.

[0084] Table 3 Electrochemical parameters of basalt in aqueous solution under different biochar treatment conditions

[0085] Table 4. Equivalent circuit model parameters of basalt in aqueous solution under different biochar treatment conditions.

[0086] Cationic chelation of biochar The collected biochar and basalt particles were mixed and separated using a magnet. The separated biochar and basalt were then digested separately using a microwave digester. ICP-MS analysis revealed (…). Figure 5 During the co-weathering of basalt and biochar, biochar can adsorb a large amount of Ca released from the solution. 2+ Mg 2+ and Fe 2+Compared to basalt treatment alone, the adsorption capacity increased by 62.7%, 197.4%, and 50.4%, respectively. This indicates that biochar, with its abundant oxygen-containing functional groups (-OH, -COOH, C=O, etc.) and porous structure, provides a large number of binding sites for cations, exhibiting a significant chelating effect.

[0087] Ca 2+ With Mg 2+ It is a key ion in the formation of carbonate precipitates such as CaCO3 and CaMg(CO3)2, Fe 2+ It is easily oxidized to Fe 3+ Further deposition occurs as low-soluble iron (oxygen) hydrides. When these ions are preferentially fixed on the biochar surface, deposition and passivation layer formation on the basalt grain surface are significantly reduced, thus maintaining the activity of the grain surface. The enrichment of ions on the biochar surface reduces the free Ca2+ in the solution. 2+ Mg 2+ and Fe 2+ The concentration of this substance disrupts the original balance at the mineral-water interface, thereby driving the weathering reaction to continue. This process effectively enhances the apparent dissolution rate of basalt.

[0088] For a mixed system of single pyrolytic carbon and basalt, during the high-temperature carbonization of biomass at 500℃, the oxygen-containing acidic functional groups on its surface (such as carboxyl groups -COOH and phenolic hydroxyl groups -OH) undergo vigorous dehydration and decarboxylation reactions, transforming into a chemically inert aromatic graphitized structure. Therefore, a single pyrolytic carbon system is extremely lacking in the ability to capture metal ions (Fe). 2+ Ca 2+ The active ligand of ) . In the absence of an effective chelating agent, its surface microenvironment will be unable to prevent Fe 2+ To sparingly soluble Fe 3+ The transformation of oxides. This inference is consistent with the higher charge transfer resistance (Ro) exhibited by the single pyrolytic carbon group in electrochemical tests. t This aligns with the observation that the high resistivity suggests its surface, similar to Group D (isolated basalt), is covered by a dense oxide passivation layer, failing to achieve surface self-cleaning through chelation. Although hydrothermal carbon is rich in functional groups, it readily aggregates when applied alone. Aggregates result in numerous active chelating sites being encased within the particles, preventing effective contact with metal ions on the basalt surface (steric hindrance). This physical shielding significantly reduces the chelation effect, preventing the efficient complexation achieved through the dispersion of the pyrolytic carbon framework as in mixed systems.

[0089] Carbon dioxide fixation calculation and model prediction To further verify the long-term carbon fixation effect of the method of the present invention, the chemical reaction mechanism of the weathering process of basalt in the aqueous solution system was analyzed, and the carbon dioxide fixation was calculated and predicted in the long term using the model.

[0090] The weathering process of basalt can be summarized as follows: 1. Dissolution of silicate minerals: (1) 2. CO2 dissolution and acidification:

[0091] 3. Carbonate precipitation:

[0092] During the weathering process, basalt releases Ca... 2+ Mg 2+ It reacts with dissolved CO2 to form stable carbonates, thereby achieving long-term CO2 fixation.

[0093] The following formula is used for calculating CO2 fixation:

[0094] Fixed mass of carbon dioxide (g); Basalt treatment compared to the control group Ca 2+ Increase in concentration (mg / L); Basalt treatment compared to the control group Mg 2+ Increase in concentration (mg / L); V: Solution volume (L); M Ca Molar mass of calcium: 40.08 g / mol M Mg Molar mass of magnesium, 24.305 g / mol M Molar mass of carbon dioxide, 44.01 g / mol Calculation results show that the addition of composite biochar can increase CO2 fixation efficiency by about 2.5 times.

[0095] Weathering dynamics were fitted using a granulation model: d(t) = d0-2k i Ω t Where d0 is the initial particle diameter, k iLet Ω represent the dissolution rate constant, and Ω be the molar volume of basalt. Simulation results show that the dissolution rate constant is significantly improved under composite biochar treatment, and the time required for 50% of the basalt particles to dissolve is reduced to 27%.

[0096] Existing single biochar technology faces significant kinetic bottlenecks and a "carbon fixation ceiling" effect in enhanced basalt weathering: High-temperature pyrolysis char, lacking acidic complexing ligands, is highly susceptible to surface passivation and pore blockage due to the easily covered pores by secondary iron / silicon oxides (as evidenced by high Ri in electrochemical impedance spectroscopy). t (as shown in the value); while single hydrolyzed carbon has high chemical activity, it is prone to agglomeration and rapid degradation in the aqueous phase due to structural defects, resulting in unsustainable reactions.

[0097] Application examples The basalt-based reinforced weathering material prepared in Example 1 was applied to farmland at a rate of 40 t / ha.

[0098] Long-term simulations show that, under farmland conditions, when basalt particles are applied at a dosage of 40 t / ha, the addition of composite biochar can increase the CO2 fixation potential by 1.36–1.39 times compared to basalt alone, and the cumulative CO2 fixation after 10 years can reach 4.97 Gt, significantly better than the 17-year cycle of basalt alone. Specific results are shown in Figure 5. In contrast, single biochar systems are limited by their respective kinetic bottlenecks, namely the surface passivation effect in the later stages of pyrolysis and the rapid degradation instability of hydrolysis itself, making it impossible to maintain a continuous and efficient driving force over a long period. This indicates that only through the composite synergistic strategy of this invention can the limitations of long-term weathering be effectively overcome, maximizing carbon sequestration benefits throughout the entire life cycle.

[0099] Table 5. Under different application years, based on 40 t·ha -1 ·year -1 Cumulative carbon sequestration benefits (t C·ha) of applying basalt and basalt + biochar -1 )

[0100] Furthermore, the corrosion current density extrapolated from the Tafel curve is positively correlated with the chemical dissolution rate of basalt. A higher dissolution rate means that Ca can be rapidly released in the initial stage of material application to soil / water. 2+ / Mg 2+ This allows for the rapid capture of atmospheric CO2, shortening the carbon fixation period. This also explains why a mixture of hydrothermal or pyrolytic carbon and basalt is unlikely to significantly shorten the carbon fixation period.

[0101] In summary, high-temperature pyrolytic carbon typically exhibits strong alkalinity, while the weathering of basalt is a proton-dependent process (H2O). + The acidic dissolution process of basalt is a key factor. If only pyrolytic carbon and basalt are mixed, the alkalinity of the pyrolytic carbon will rapidly neutralize the free protons in the system during weathering, creating a pH buffering effect. This high pH environment significantly reduces the dissolution kinetics of silicate minerals, thus inhibiting the weathering reaction of basalt in its early stages.

[0102] The high-temperature carbonization process also leads to the decomposition of a large number of active functional groups in biomass, forming highly aromatic and graphitized structures. This means that the surface of pyrolytic carbon lacks the ability to actively complex metal ions (Ca). 2+ Mg 2+ The active sites of basalt are more like physical adsorbents than chemical reaction promoters, and it cannot effectively reduce the ion saturation of the mineral surface through complexation. Due to the lack of complexation protection by organic acids, the dissolved metal cations readily combine with carbonate ions in the high pH microenvironment of pyrolytic carbon, forming a carbonate precipitation layer on the basalt surface. This "shell" encapsulates the unreacted basalt, blocking water contact with the rock and causing the weathering reaction to terminate prematurely.

[0103] In the case of a mixed system of hydrothermal carbon and basalt, the hydrothermal carbon mainly forms a microsphere structure through dehydration and polymerization reactions, and its specific surface area and porosity are much lower than those of pyrolytic carbon. This means that it cannot provide sufficient diffusion channels for the reaction. The products of the reaction tend to accumulate around the material and cannot diffuse quickly into the bulk solution, resulting in excessively high local ion concentrations and inhibiting the forward reaction.

[0104] Because hydrothermal carbon contains a large number of polar and non-polar regions on its surface and has very small particles, it is prone to agglomeration in aqueous solutions. Agglomerated hydrothermal carbon binds together, significantly reducing its effective contact area with basalt particles and preventing its acidic functional groups from functioning fully.

[0105] Compared to mixing pyrolytic carbon or hydrothermal carbon alone with basalt, this invention utilizes the well-developed macroporous structure of high-temperature pyrolytic carbon as a micro-framework and mass transfer channel, effectively supporting and dispersing the fine-particle, easily agglomerated hydrothermal carbon. This composite structure not only solves the problem of mass transfer obstruction caused by hydrothermal carbon accumulation, but also utilizes the high specific surface area of ​​pyrolytic carbon to uniformly anchor the acidic functional groups (such as -COOH, -OH) abundant in hydrothermal carbon around the basalt particles. This greatly increases the effective contact area of ​​the water-rock-carbon three-phase interface and improves the reaction rate. Addressing the pH sensitivity of basalt weathering, the mixed system achieves perfect acid-base balance control. The organic acids released by the hydrothermal carbon can continuously provide protons (H+). +This neutralizes the strong alkalinity of the high-temperature pyrolytic char, eliminating the alkaline inhibition effect; at the same time, the buffering capacity of the pyrolytic char prevents the structural disintegration of biochar caused by excessively high local acidity. This self-regulating weakly acidic-neutral microenvironment is the optimal advantage of silicate mineral dissolution kinetics, enabling the long-term maintenance of highly efficient weathering reactions.

[0106] The hybrid system of this invention combines the chemical complexing ability of hydrothermal char with the electron transport ability of pyrolytic char. The dissolved organic matter (DOM) released from the hydrothermal char acts as a powerful chelating agent, rapidly capturing Ca released from basalt. 2+ Mg 2+ The carbon sequestration process prevents ions from re-precipitating on the rock surface and forming a passivation layer. Simultaneously, highly graphitized pyrolytic carbon acts as an electron shuttle, accelerating redox reactions on the mineral surface. Together, these two processes ensure the continuous exposure of fresh basaltic reaction interfaces, significantly extending the effective carbon sequestration cycle and maximizing carbon sequestration throughout the entire life cycle.

[0107] In addition, this invention also explored the effect of the ratio of pyrolytic carbon to hydrothermal carbon in composite biochar on weathering or carbon fixation effects. Experimental studies revealed that the mass ratio of high-temperature pyrolytic carbon to hydrolytic carbon has a significant nonlinear effect on the weathering rate of basalt. Controlling the ratio within the optimal range (1:3~3:1) maximizes the synergistic effect of the two. If the proportion of high-temperature pyrolytic carbon is too high, although the system possesses excellent pore structure and conductivity, it also brings negative effects. High-temperature pyrolytic carbon is usually strongly alkaline; an excessively high proportion will rapidly neutralize acidic substances in the system, leading to an increase in the pH value of the microenvironment, deviating from the optimal range for acidic dissolution of silicate minerals. As the proportion of hydrolytic carbon decreases, the density of oxygen-containing functional groups that provide proton attack and complexation capabilities in the system decreases significantly, resulting in insufficient chemical erosion ability on the basalt surface and limiting the weathering rate. If the proportion of hydrolytic carbon is too high, although the initial chemical activity is extremely high, defects in the physical structure will gradually be exposed. Hydrolyzed carbon particles are small and easily aggregate. An excessively high proportion of them can lead to overfilling of the large pores in high-temperature pyrolytic carbon, blocking mass transfer channels and hindering the diffusion of water and reaction products. The structure of hydrolyzed carbon is relatively unstable. An excessively high proportion of it can cause the carbon skeleton to degrade too quickly in long-term reactions, losing its dispersing and supporting effect on basalt particles, resulting in a significant decrease in the weathering rate in the later stages of the reaction.

[0108] Experiments have shown that when the composite ratio of the two is around 1:1 by mass, the rigid framework provided by the high-temperature pyrolytic carbon is just right to support an appropriate amount of hydrolyzed carbon particles, ensuring both abundant exposure of acidic functional groups and maintaining unobstructed pore mass transfer channels. At the same time, the alkalinity of the pyrolytic carbon and the acidity of the hydrolyzed carbon neutralize each other, forming a weakly acidic-neutral buffer system that can be maintained for a long time, thereby maximizing the carbon fixation efficiency of basalt.

[0109] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A basalt-based reinforced weathering material, characterized in that, The basalt-based enhanced weathering material is composed of basalt particles and composite biochar, wherein the composite biochar is composed of pyrolytic carbon and hydrothermal carbon, and the mass ratio of pyrolytic carbon to hydrothermal carbon is 1:9 to 9:

1.

2. The basalt-based reinforced weathering material according to claim 1, characterized in that, The mass ratio of basalt particles to composite biochar is 1:10 to 10:

1.

3. The basalt-based reinforced weathering material according to claim 1, characterized in that, The mass ratio of pyrolytic char to hydrothermal char is 1:3 to 3:1, and the mass ratio of basalt particles to composite biochar is 1:5 to 5:

1.

4. A method for preparing a basalt-based reinforced weathering material, characterized in that, A composite biochar of pyrolytic carbon and hydrolytic carbon is added to basalt particles and mixed evenly to obtain a basalt-based reinforced weathering material. The mass ratio of pyrolytic carbon to hydrolytic carbon is 1:9 to 9:1, and the mass ratio of basalt particles to composite biochar is 1:10 to 10:

1.

5. A method for enhanced weathering based on basalt, characterized in that, Includes the following steps: (1) Disperse basalt particles in water to form a basalt particle dispersion; (2) Subsequently, a composite biochar of pyrolytic carbon and hydrolytic carbon was added to the basalt particle dispersion, mixed well, and then subjected to weathering reaction.

6. The enhanced weathering method according to claim 5, characterized in that, The basalt particles are silicate particles ground by a ball mill, and the average particle size of the basalt particles ranges from 20 to 90 μm.

7. The enhanced weathering method according to claim 5, characterized in that, The concentration of the basalt particle solution in step (1) is 2~20 g / L. After adding the composite biochar, the mass concentration of the composite biochar in the dispersion is 2~20 g / L.

8. The enhanced weathering method according to claim 7, characterized in that, The concentration of the basalt particle solution in step (1) is 3~8 g / L. After adding the composite biochar, the mass concentration of the composite biochar in the dispersion is 3~8 g / L.

9. The enhanced weathering method according to claim 5, characterized in that, In step (2), it is preferable to use a shaker to mix thoroughly. The shaker conditions are 150-200 rpm and the mixing time is 0-55 days.

10. The enhanced weathering method according to claim 5, characterized in that, The drying method described in step (2) includes at least one of hot air drying, vacuum drying, and freeze drying. The temperature of the hot air drying is 50~80℃ and the time is 10~15 hours.

11. A method for enhancing carbon fixation based on basalt, characterized in that, The enhancement method includes adding a composite biochar of pyrolytic carbon and hydrolytic carbon to basalt particles, and using the material obtained after uniform mixing to fix carbon.

12. The strengthening method according to claim 11, characterized in that, The enhancement method includes adding a composite biochar of pyrolytic carbon and hydrolytic carbon to a dispersion of basalt particles, and using the mixed dispersion for carbon fixation.

13. The strengthening method according to claim 11 or 12, characterized in that, The method for preparing the pyrolytic char includes: carbonizing the biochar raw material by dry distillation under nitrogen at 400~600 ℃ to obtain the pyrolytic char; the method for preparing the hydrothermal char includes: hydrothermally synthesizing the biochar raw material in a water-containing hydrothermal reactor to obtain the hydrolytic char.

14. The strengthening method according to claim 13, characterized in that, In the preparation of hydrothermal char, the solid-liquid mass ratio of biochar raw material to water is 1:5~10. The mixture of biochar raw material and water is stirred and heated to 300 ℃, then immediately cooled at room temperature. The generated hydrothermal char is collected by filtration and centrifugation and then dried.

15. The strengthening method according to claim 14, characterized in that, The biochar raw material is selected from at least one of crop straws, including corn straw, rice straw, and wheat straw.

16. Use of the enhanced weathering material according to any one of claims 1 to 3 in farmland carbon sequestration.

17. The use according to claim 16, characterized in that, The application includes the following steps: basalt-based reinforced weathering material is manually sprinkled into farmland at an addition rate of 2-6% and 20-60 t / ha, and then the basalt is evenly mixed with the soil using traditional plowing methods.

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