A kind of organic silicon quaternary ammonium salt catalyst for strengthening CO2 mineralization sealing and its preparation method and application

Abstract

The application provides a kind of organic silicon quaternary ammonium salt catalyst for strengthening CO2 mineralization sequestration and its preparation method and application, belongs to catalyst preparation technical field.The preparation method of the organic silicon quaternary ammonium salt catalyst, including steps: hydrogen-containing polydimethylsiloxane and allyl glycidyl ether are added to organic solvent, under the catalysis of platinum catalyst, carry out silicon hydrogen addition reaction, obtain epoxy group end-capped polysiloxane intermediate;The obtained epoxy group end-capped polysiloxane intermediate is added to alcohol solvent, add binary polyether amine to carry out ammonolysis ring-opening reaction, obtain polyether amine end-capped tertiary amine intermediate;The obtained polyether amine end-capped tertiary amine intermediate is added to polar solvent, add quaternization reagent to carry out reaction, obtain the organic silicon quaternary ammonium salt catalyst for strengthening CO2 mineralization sequestration.The catalyst of the application can accelerate the dissolution of calcium silicate and the mass transfer absorption of CO2, inhibit the formation of SiO2 passivation layer, greatly improve the reaction efficiency and CO2 conversion rate.

Description

Technical Field

[0001] This invention relates to an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration, its preparation method and application, belonging to the field of catalyst preparation technology. Background Technology

[0002] Currently, carbon dioxide emissions continue to increase, and the problem of global warming is becoming increasingly serious. Carbon dioxide capture, utilization, and storage (CCUS) technology is a key pathway to achieve large-scale carbon emission reduction. This technology system can efficiently separate and capture carbon dioxide from industrial emission sources or the atmosphere, and then convert it into high-value-added resources or store it in underground reservoirs, thereby reducing atmospheric carbon dioxide concentration and mitigating the trend of global warming. In the CCUS technology chain, the efficient capture of CO2 from industrial emission sources (such as coal-fired power plants and steel plants) is the primary link, and its technical performance and operational efficiency directly determine the engineering feasibility and economic applicability of the entire CCUS technology system.

[0003] Currently, various methods exist for capturing carbon dioxide. Industrially, chemical absorption is predominant (using alkaline absorbents such as ethanolamine and ammonia to permanently fix CO2 into carbonates through chemical reactions, thus achieving efficient separation of CO2 from the main flue gas). This method is widely used due to its high technological maturity. However, a more promising end-of-pipe storage method involves using industrial solid waste rich in calcium silicate (CaSiO3), such as steel slag and ore slag, to mineralize CO2, generating economically valuable calcium carbonate (CaCO3) and silicon dioxide (SiO2), truly achieving "turning waste into treasure" and permanent CO2 sequestration.

[0004] Despite the advanced concept of carbon dioxide mineralization and storage, its industrial application faces two major bottlenecks, resulting in insufficient economic viability and feasibility:

[0005] 1. Slow reaction kinetics: Calcium silicate has extremely low solubility in the aqueous phase, and calcium ions (Ca...)... 2+ The release rate is slow, which means that the entire mineralization reaction takes several hours or even days, and the CO2 conversion rate is generally less than 60%, which cannot meet the efficiency requirements of continuous industrial production.

[0006] 2. Product passivation layer obstruction: The silicon dioxide (SiO2) generated in the reaction will densely coat the surface of the unreacted calcium silicate particles, forming a "passivation layer" that severely hinders the reaction of CO2 and Ca. 2+ Mass transfer is impaired, causing the reaction to stop prematurely. To solve this problem, traditional processes often rely on harsh conditions such as high temperature, high pressure, or strong acid pretreatment, resulting in high energy consumption per unit (usually >100kWh / t-CO2) and high operating costs.

[0007] Numerous patent documents have reported on catalysts or absorbents for capturing carbon dioxide. For example, Chinese patent document CN120571577A discloses a method for preparing an in-situ carbon dioxide capture catalyst, including the following steps: S1. Mixing and stirring Bi(NO3)3·5H2O, dilute nitric acid, and an adsorption modifier; S2. Filtering to obtain a white precipitate, drying it, and then slowly heating it to 450℃ in a muffle furnace for 20-30 min to obtain a pale yellow solid; S3. Dispersing it in a modified solution, sealing the reactor, and purging it with argon gas for 10-15 min; S4. Injecting CH4, reacting under xenon lamp irradiation for 2 h, filtration of the solid, rinsing it with deionized water, and drying it at 60℃ for 10-12 h to obtain a high-performance catalyst that captures carbon dioxide and inhibits methane peroxidation through the synergistic effect of the adsorption modifier and the modified solution. Chinese patent document CN120771700A discloses a two-phase absorbent for capturing carbon dioxide, comprising a polyamine compound, a compound containing amino groups and ether bonds, a phase-separating agent, and water; wherein the compound containing amino groups and ether bonds includes a monoamine compound containing ether bonds and a polyamine compound containing ether bonds; the mass ratio of the monoamine compound containing ether bonds to the polyamine compound containing ether bonds is 0.1-5:1.

[0008] However, existing CO2 mineralization and capture technologies have prominent drawbacks such as low reaction efficiency, high energy consumption, and reaction termination due to passivation layers. They cannot simultaneously achieve high reaction rates and high conversion rates under mild conditions, resulting in excessively long reaction times, high unit energy consumption, and poor economic efficiency. Furthermore, there is a lack of effective means to suppress the silica (SiO2) passivation layer generated during the reaction, which leads to the blockage of mass transfer channels and the inability to continue the reaction. The preparation process of the catalyst or absorbent itself is complex, requires harsh conditions, and has high raw material costs and poor environmental friendliness.

[0009] Therefore, developing a highly efficient catalyst that can simultaneously accelerate calcium ion release and inhibit passivation layer formation under mild conditions (normal pressure, medium and low temperature) has become an urgent need to break through this technological bottleneck and promote the development of the CCUS industry. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration, along with its preparation method and applications. The catalyst of this invention uses polysiloxane as the main chain, introducing quaternary ammonium salt groups through polyetheramine end-capping technology to form an amphiphilic structure with clear interfacial activity and passivation layer inhibition function. It can target the gas-liquid-solid reaction interface, significantly accelerating the dissolution of calcium silicate and CO2 mass transfer and absorption, and effectively inhibiting the formation of the SiO2 passivation layer. This results in a substantial increase in reaction efficiency and CO2 conversion rate under mild conditions, while reducing energy consumption. Furthermore, the preparation method of this catalyst is simple, uses mild conditions, readily available raw materials, and is environmentally friendly. It enables the controllable preparation of stable organosilicon quaternary ammonium salt polymers, making it suitable for industrial production.

[0011] The technical solution of the present invention is as follows: A method for preparing an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration includes the following steps: (1) Hydrogen-terminated polydimethylsiloxane and allyl glycidyl ether were added to an organic solvent and subjected to a hydrosilylation reaction under the catalysis of a platinum catalyst. After the reaction was completed, the solvent was removed to obtain an epoxy-terminated polysiloxane intermediate. (2) The epoxy-terminated polysiloxane intermediate obtained in step (1) is added to an alcohol solvent, and a di-polyetheramine is added to carry out an ammonolysis ring-opening reaction to obtain a polyetheramine-terminated tertiary amine intermediate. (3) The polyetheramine-terminated tertiary amine intermediate obtained in step (2) is added to a polar solvent and a quaternization reagent is added to carry out the reaction. After the reaction is completed, the product is separated and purified to obtain an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and storage.

[0012] According to a preferred embodiment of the present invention, the hydrogen content of the hydrogen-terminated polydimethylsiloxane in step (1) is 0.5-1.5%; the hydrogen-terminated polydimethylsiloxane is a dihydrogen-terminated polydimethylsiloxane, and the hydrogen content refers to the percentage of the mass of hydrogen in the Si-H bond of the hydrogen-terminated polydimethylsiloxane to the mass of the hydrogen-terminated polydimethylsiloxane.

[0013] According to a preferred embodiment of the present invention, the molar ratio of hydrogen in the Si-H bond of the hydrogen-terminated polydimethylsiloxane to allyl glycidyl ether in step (1) is 1:1.05-1.2.

[0014] According to a preferred embodiment of the present invention, the organic solvent in step (1) is toluene and / or isopropanol; the volume ratio of the organic solvent to the mass of the hydrogen-terminated polydimethylsiloxane is 15-40 mL: 1 g.

[0015] According to a preferred embodiment of the present invention, the mass of platinum in the platinum catalyst in step (1) is 0.001-0.005% of the mass of hydrogen-terminated polydimethylsiloxane; the platinum catalyst is a 0.5-2% isopropanol chloroplatinate solution.

[0016] According to a preferred embodiment of the present invention, the temperature of the hydrosilylation reaction in step (1) is 60-85°C; the time of the hydrosilylation reaction is 4-8 hours; and the hydrosilylation reaction is carried out under the protection of a protective gas, wherein the protective gas is nitrogen or argon.

[0017] According to a preferred embodiment of the present invention, the alcohol solvent in step (2) is methanol or ethanol; the volume ratio of the alcohol solvent to the mass of the epoxy-terminated polysiloxane intermediate is 40-60 mL: 1 g.

[0018] According to a preferred embodiment of the present invention, the binary polyetheramine in step (2) is selected from one of polyetheramine D230, polyetheramine D400 or polyetheramine EDR-148; the molar ratio of the amino group (NH2) in the binary polyetheramine to the epoxy group in the epoxy-terminated polysiloxane intermediate is 1-1.1:1; the molar amount of the epoxy group is calculated as the molar amount of hydrogen in the Si-H bond in the hydrogen-terminated polydimethylsiloxane.

[0019] According to a preferred embodiment of the present invention, the temperature of the ammonia ring-opening reaction in step (2) is 50-80°C; the ammonia ring-opening reaction is carried out under a pressure of 0.2-0.5 MPa; and the time of the ammonia ring-opening reaction is 3-10 hours.

[0020] According to a preferred embodiment of the present invention, in step (2), after the ammonolysis ring-opening reaction is completed, excess reagents and solvents are removed to obtain a polyetheramine-terminated tertiary amine intermediate.

[0021] According to a preferred embodiment of the present invention, the polar solvent in step (3) is isopropanol or N,N-dimethylformamide; the volume ratio of the polar solvent to the mass of the polyetheramine-terminated tertiary amine intermediate is 60-100 mL: 1 g.

[0022] According to a preferred embodiment of the present invention, the quaternizing agent in step (3) is one of benzyl chloride, dimethyl sulfate or chloromethane; the molar ratio of the quaternizing agent to the hydrogen in the Si-H bond of the hydrogen-terminated polydimethylsiloxane is 1-1.2:1.

[0023] According to a preferred embodiment of the present invention, the temperature of the reaction in step (3) is 70-85°C and the reaction time is 5-10 hours.

[0024] According to a preferred embodiment of the present invention, the separation and purification step in step (3) is as follows: the solvent is removed by vacuum distillation of the obtained reaction solution to obtain a crude product, and the crude product is recrystallized using a mixed solvent of ethyl acetate and n-hexane, wherein the volume ratio of ethyl acetate to n-hexane in the mixed solvent is 2-3:1.

[0025] The present invention also provides an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and storage, which is prepared by the above preparation method. The obtained organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and storage has a number average molecular weight (Mn) of 2000-5000, a weight average molecular weight (Mw) of 3000-6000, and a molecular weight distribution index (PDI) of 1.3-1.6.

[0026] According to the present invention, the above-mentioned organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration is applied in CO2 mineralization and capture.

[0027] The technical features and beneficial effects of this invention are as follows: The organosilicon quaternary ammonium salt catalyst for enhanced CO2 mineralization and storage of the present invention uses polysiloxane as the main chain and introduces quaternary ammonium salt groups through polyetheramine end-capping technology to form an amphiphilic structure with clear interfacial activity and passivation layer inhibition function. It has the following characteristics: (1) It has a unique mechanism for targeted inhibition of the passivation layer. Targeted adsorption: silane groups have a strong affinity for the surface of the reaction product silica (SiO2) and can preferentially and firmly adsorb onto the SiO2 passivation layer; (2) Inhibition of passivation: Through steric hindrance effect and surface modification, it prevents the dense accumulation of passivation layer particles, keeping it in a loose and porous structure, thus failing to effectively block the diffusion of reactants and products. The loose product layer ensures continuous diffusion; the passivation layer is induced into a loose structure, CO2 and Ca 2+ The effective diffusion coefficient is increased by an order of magnitude, and the reaction interface is always exposed; (3) Quaternary ammonium cations form an electric double layer in the pores, further repelling the redeposition of SiO2 colloids. Compared with existing catalysts, the catalyst of the present invention has the following advantages: 1. The organosilicon quaternary ammonium salt catalyst for enhanced CO2 mineralization and sequestration of the present invention has readily available raw materials, mild reaction conditions, and a simple and easy-to-control process, making it suitable for industrial production.

[0028] 2. The organosilicon quaternary ammonium salt catalyst for enhanced CO2 mineralization and storage of the present invention, through its "targeted inhibition" mechanism, successfully transforms the traditional dense, low-porosity passivation layer into a loose, high specific surface area, and large-pore structure. The formation of this structure ensures that the reaction interface is always exposed and the mass transfer channels are unobstructed.

[0029] 3. The organosilicon quaternary ammonium salt catalyst of the present invention, which enhances CO2 mineralization and sequestration, can target the gas-liquid-solid reaction interface, significantly accelerate the dissolution of calcium silicate and the mass transfer and absorption of CO2, and effectively inhibit the formation of the SiO2 passivation layer. This significantly improves reaction efficiency and CO2 conversion rate under mild conditions, while reducing energy consumption, improving wettability, and helping the reaction solution to better wet and spread on the surface of calcium silicate particles, increasing the effective reaction area. As an ammonium ion precursor, it can release ammonium ions (NH4+) under reaction conditions. + ), providing H + It effectively promotes the dissolution of calcium silicate and accelerates the dissolution of calcium ions (Ca). 2+ The release of ) and the dissolution rate are accelerated simultaneously.

[0030] In summary, this invention provides a highly efficient, low-energy-consumption CO2 mineralization and capture catalyst that can specifically solve the passivation layer problem, and provides a simple, economical, and environmentally friendly synthesis route. Attached Figure Description

[0031] Figure 1 Fourier exchange infrared spectrum of the organosilicon quaternary ammonium salt catalyst prepared in Example 1 for enhancing CO2 mineralization and sequestration.

[0032] Figure 2 This is a schematic diagram of thermogravimetric analysis of the organosilicon quaternary ammonium salt catalyst prepared in Example 1 for enhancing CO2 mineralization and storage.

[0033] Figure 3 The molecular weight analysis diagram is shown for the organosilicon quaternary ammonium salt catalyst prepared in Example 1 for enhancing CO2 mineralization and storage. Detailed Implementation

[0034] The present invention will be described in detail below with reference to specific embodiments, but the present invention is not limited thereto.

[0035] The hydrogen-terminated polydimethylsiloxane used in the examples is a dihydrogen-terminated polydimethylsiloxane with a hydrogen content of 0.5-1.5%. The hydrogen content refers to the percentage of the mass of hydrogen in the Si-H bonds of the hydrogen-terminated polydimethylsiloxane relative to the mass of the hydrogen-terminated polydimethylsiloxane.

[0036] Example 1 A method for preparing an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration includes the following steps: (1) Under nitrogen protection, hydrogen-terminated polydimethylsiloxane with a hydrogen content of 0.5% and allyl glycidyl ether were added to toluene at a molar ratio of n(Si-H):n(C=C)=1:1.05, and the volume ratio of toluene to the mass ratio of hydrogen-terminated polydimethylsiloxane was 26 mL:1 g; then a platinum catalyst (a 0.5% isopropanol chloroplatinate solution) was added, and the mass of platinum in the platinum catalyst was 0.001% of the mass of hydrogen-terminated polydimethylsiloxane; then the mixture was heated to 60 °C and subjected to a hydrosilylation reaction for 8 hours under nitrogen protection; after the reaction was completed, the solvent was removed by vacuum distillation to obtain an epoxy-terminated polysiloxane intermediate; (2) Polyetheramine D230 and the epoxy-terminated polysiloxane intermediate obtained in step (1) were added to ethanol at a molar ratio of amino to epoxy groups of n(NH2):n(epoxy) = 1:1. The volume ratio of ethanol to the mass of epoxy-terminated polysiloxane intermediate was 51 mL: 1 g. The resulting mixture was transferred to a reaction vessel and pressurized to 0.2 MPa. The reaction was carried out at 0.2 MPa and 50 °C for 10 hours. After the reaction was completed, excess reagents and solvents were removed by vacuum distillation to obtain the polyetheramine-terminated tertiary amine intermediate. (3) According to the molar ratio of hydrogen in the Si-H bond of chloromethane to hydrogen in hydrogen-terminated polydimethylsiloxane is 1.1:1, chloromethane and the polyetheramine-terminated tertiary amine intermediate obtained in step (3) are added to N,N-dimethylformamide. The volume ratio of N,N-dimethylformamide to the mass ratio of polyetheramine-terminated tertiary amine intermediate is 76mL:1g. The resulting mixed liquid is heated to 70°C and passed through a condenser for 10 hours. After the reaction is completed, the solvent is removed by vacuum distillation to obtain crude product. The crude product is recrystallized using an ethyl acetate-n-hexane mixed solvent (the volume ratio of ethyl acetate to n-hexane in the mixed solvent is 2:1) to obtain an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and storage.

[0037] Example 2 A method for preparing an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration includes the following steps: (1) Under nitrogen protection, hydrogen-terminated polydimethylsiloxane with a hydrogen content of 1.0% and allyl glycidyl ether were added to toluene at a molar ratio of n(Si-H):n(C=C)=1:1.1, and the volume ratio of toluene to the mass ratio of hydrogen-terminated polydimethylsiloxane was 28 mL:1 g. Then, a platinum catalyst (a 1% mass fraction of isopropanol chloroplatinate solution) was added, and the mass of platinum in the platinum catalyst was 0.003% of the mass of hydrogen-terminated polydimethylsiloxane. Then, the mixture was heated to 75°C and subjected to a hydrosilylation reaction for 6 hours under nitrogen protection. After the reaction was completed, the solvent was removed by vacuum distillation to obtain an epoxy-terminated polysiloxane intermediate. (2) Add polyetheramine D400 and the epoxy-terminated polysiloxane intermediate obtained in step (1) to ethanol at a molar ratio of amino to epoxy group of n(NH2):n(epoxy group) = 1.05:1. The volume ratio of ethanol to the mass ratio of epoxy-terminated polysiloxane intermediate is 55 mL: 1 g. Transfer the resulting mixture to a reaction vessel and pressurize it to 0.4 MPa. React at 0.4 MPa and 70 °C for 5 hours. After the reaction is completed, remove excess reagents and solvents by vacuum distillation to obtain the polyetheramine-terminated tertiary amine intermediate. (3) According to the molar ratio of hydrogen in the Si-H bond of chloromethane to hydrogen in hydrogen-terminated polydimethylsiloxane is 1.1:1, chloromethane and the polyetheramine-terminated tertiary amine intermediate obtained in step (3) are added to N,N-dimethylformamide. The volume ratio of N,N-dimethylformamide to the mass ratio of polyetheramine-terminated tertiary amine intermediate is 78mL:1g. The resulting mixed liquid is heated to 75°C and passed through a condenser for 7 hours. After the reaction is completed, the solvent is removed by vacuum distillation to obtain the crude product. The crude product is recrystallized using an ethyl acetate-n-hexane mixed solvent (the volume ratio of ethyl acetate to n-hexane in the mixed solvent is 2.5:1) to obtain the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and storage.

[0038] Example 3 A method for preparing an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration includes the following steps: (1) Under nitrogen protection, hydrogen-terminated polydimethylsiloxane with a hydrogen content of 1.5% and allyl glycidyl ether were added to toluene at a molar ratio of n(Si-H):n(C=C)=1:1.2, and the volume ratio of toluene to the mass ratio of hydrogen-terminated polydimethylsiloxane was 30mL:1g; then a platinum catalyst (a 2% mass fraction isopropanol chloroplatinate solution) was added, and the mass of platinum in the platinum catalyst was 0.005% of the mass of hydrogen-terminated polydimethylsiloxane; then the mixture was heated to 85°C and subjected to a hydrosilylation reaction for 4 hours under nitrogen protection; after the reaction was completed, the solvent was removed by vacuum distillation to obtain an epoxy-terminated polysiloxane intermediate; (2) Add polyetheramine EDR-148 and the epoxy-terminated polysiloxane intermediate obtained in step (1) to ethanol at a molar ratio of amino to epoxy group n(NH2):n(epoxy group) = 1.1:1. The volume ratio of ethanol to the mass ratio of epoxy-terminated polysiloxane intermediate is 60 mL: 1 g. Transfer the resulting mixture to a reaction vessel and pressurize it to 0.5 MPa. React at 0.5 MPa and 80 °C for 3 hours. After the reaction is completed, remove excess reagents and solvents by vacuum distillation to obtain the polyetheramine-terminated tertiary amine intermediate. (3) According to the molar ratio of hydrogen in the Si-H bond of chloromethane to hydrogen in hydrogen-terminated polydimethylsiloxane is 1.1:1, chloromethane and the polyetheramine-terminated tertiary amine intermediate obtained in step (3) are added to N,N-dimethylformamide. The volume ratio of N,N-dimethylformamide to the mass ratio of polyetheramine-terminated tertiary amine intermediate is 80 ml: 1 g. The resulting mixed liquid is heated to 85 °C and passed through a condenser for 5 hours. After the reaction is completed, the solvent is removed by vacuum distillation to obtain crude product. The crude product is recrystallized using an ethyl acetate-n-hexane mixed solvent (the volume ratio of ethyl acetate to n-hexane in the mixed solvent is 3:1) to obtain an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and storage.

[0039] Example 4 A method for preparing an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and storage is described in Example 1, except that dimethyl sulfate is used instead of chloromethane in step (3).

[0040] Comparative Example 1 A method for preparing an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration is as described in Example 1, except that step (3) is not performed.

[0041] Comparative Example 2 A method for preparing an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and storage is described in Example 4, except that step (3) is not performed.

[0042] Experimental Example 1 1. Infrared analysis The molecular structure of the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration prepared in Example 1 was characterized by Fourier transform infrared spectroscopy, and the results are as follows: Figure 1 As shown in the spectrum. At 1123.4 cm⁻¹ -1 The strong and broad absorption peak at 2924.5 cm⁻¹ is attributed to the asymmetric stretching vibration of the Si-O-Si bond, confirming the successful construction of the polysiloxane backbone via hydrosilylation. -1 and 1451.5cm -1 The absorption peaks at 3417.7 cm⁻¹ correspond to the stretching and bending vibrations of aliphatic CH bonds, respectively, reflecting the abundance of methyl and methylene structural units in the molecule. These groups originate from polydimethylsiloxane chains, polyetheramine fragments, and quaternary ammonium alkyl side chains. -1 A broad absorption band is observed at 1614.4 cm⁻¹, which is related to the NH stretching vibration and possible OH vibration in the polyetheramine chain segment; -1 With 1560.1cm -1 The absorption in the vicinity is related to the bending vibration of NH or the absorption of quaternary ammonium salt CN.+ The vibrational modes are consistent, jointly indicating the completion of the amino group reaction and quaternization process. 954 cm⁻¹ -1 The absorption at this point may be attributed to the Si-OC vibration; 617.2 cm⁻¹ -1 With 478.2cm -1 The absorption peak at this location indicates the characteristic vibrations of Si-CH3 rocking and Si-O-Si bending. In summary, the characteristic peaks in the infrared spectrum are consistent with the designed target product structure, confirming the successful synthesis of the polyetheramine-terminated organosilicon quaternary ammonium salt catalyst.

[0043] 2. Thermogravimetric analysis (TG-DTG) A schematic diagram of the thermogravimetric analysis of the organosilicon quaternary ammonium salt catalyst prepared in Example 1 for enhancing CO2 mineralization and sequestration is shown below. Figure 2 As shown, the TG curve exhibits three main stages of mass change during heating, which corroborate the characteristic peak positions on the DTG curve. In the initial stage, a small weight loss step appears around 107.5℃, corresponding to a shoulder peak on the DTG curve, with a mass loss of approximately 9.8%. This stage is mainly attributed to the volatilization of physically adsorbed water and possibly residual trace amounts of low-boiling-point solvents in the sample, indicating that the product still contains a small amount of adsorbed components after purification, but these are easily removed at subsequent application temperatures. As the temperature increases, the TG curve shows a gentle weight loss plateau around 167℃, and the DTG curve changes accordingly at this point. This stage may be related to the initial decomposition of some unstable organic segments in the organosilicon quaternary ammonium salt catalyst or the early thermal behavior of the quaternary ammonium salt groups. The primary decomposition process occurs in the high-temperature region. The TG curve shows a sharp mass loss between approximately 300℃ and 600℃, while the DTG curve exhibits a sharp negative peak at 584℃. The cumulative weight loss at this stage reaches as high as 56.5%, clearly corresponding to the bulk thermal decomposition of the organic components in the organosilicon quaternary ammonium salt catalyst molecule, including the breakage and carbonization of polyetheramine segments, the quaternary ammonium salt structure, and some organosilicon side chains. After 600℃, the TG curve flattens out, and the residual mass stabilizes at approximately 22%. This residue mainly originates from the highly thermally stable Si-O-Si inorganic framework and any possible silica residues. In summary, this catalyst exhibits good thermal stability under application conditions below 200℃, with a bulk decomposition temperature as high as 584℃, demonstrating its ability to withstand temperature fluctuations during actual reactions and providing crucial thermodynamic evidence for its long-term use under mild conditions.

[0044] 3. Molecular weight determination (GPC) The relative molecular masses of the organosilicon quaternary ammonium salt catalysts prepared in Examples 1-4 for enhancing CO2 mineralization and sequestration were determined using a PL-GPC50 gel permeation chromatograph. The test results are shown in Table 1. The molecular weight analysis chromatogram of Example 1 is shown below. Figure 3As shown.

[0045] Table 1. Results of relative molecular mass determination of organosilicon quaternary ammonium salt catalysts by gel chromatography.

[0046] The experimental data above show that the molecular weight distribution of the prepared organosilicon quaternary ammonium salt catalyst for enhanced CO2 mineralization and sequestration is relatively small, indicating that the reaction conditions selected during catalyst synthesis are suitable, effectively suppressing side reactions and resulting in a high catalyst yield. The organosilicon quaternary ammonium salt catalyst has a number-average molecular weight of no more than 5000, making it an oligomer with a narrow relative molecular mass distribution. This narrow distribution range reduces the likelihood of localized over-reaction or incomplete reaction, fundamentally optimizing the regeneration performance of captured carbon dioxide and reducing regeneration energy consumption and material loss.

[0047] Experimental Example 2: Application in Simulated Flue Gas CO2 Capture Performance Testing The study verified the CO2 capture performance of the prepared organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration under simulated flue gas conditions of a coal-fired power plant, and compared it with that of the traditional ethanolamine (MEA) absorbent.

[0048] Test samples: Organosilicon quaternary ammonium salt catalyst products for enhancing CO2 mineralization and sequestration prepared in the examples and comparative examples.

[0049] Test method: Absorption experiment: A catalyst aqueous dispersion with a concentration of 2.0 wt% was prepared as the absorbent. In a bubbling absorption apparatus, simulated flue gas (a mixture of CO2 and N2, with CO2 volume fraction of 15%) was passed into 200 mL of the absorbent at a constant flow rate of 200 mL / min under constant temperature conditions of 40℃, and the reaction was continued for 120 minutes. The change in CO2 concentration in the outlet gas was monitored online using a high-precision gas chromatograph, and the cumulative absorption, average absorption rate, and conversion rate at specific time points were calculated.

[0050] Comparative experiment: Under exactly the same experimental conditions, parallel experiments were conducted with conventional MEA (ethanolamine) aqueous solution of equal concentration (2.0 wt%) and blank deionized water as a comparison.

[0051] Experimental Results and Discussion: Through system testing, the key performance parameters shown in Table 2 were obtained. The data indicates that the product of this invention is comprehensively superior to traditional MEA absorbents in CO2 capture performance.

[0052] Table 2 Comparison of Key Performance Parameters for CO2 Capture

[0053] As shown in Table 2, taking Example 1 as an example, the saturated absorption capacity of the product of this invention reaches 1.85 mol / L, significantly higher than that of MEA (1.52 mol / L). This is mainly attributed to the electrostatic enrichment effect of the quaternary ammonium salt groups in the catalyst molecule on CO2 and the good affinity between the polyether segments and CO2 molecules, which jointly enhance the physical dissolution and chemical binding capabilities. The average absorption rate of the product of this invention is 0.021 mol / L·min, which is about 40% higher than that of MEA (0.015 mol / L·min). This fully demonstrates the excellent interfacial activity of its molecular structure at the gas-liquid interface, which can rapidly reduce interfacial tension and greatly promote the mass transfer and diffusion process of CO2 from the gas phase to the liquid phase. At the 120-minute reaction node, the CO2 conversion rate of the product of this invention is as high as 92.5%, while that of MEA is only 76.0%. This not only proves its high reaction efficiency but also suggests that it may have better anti-degradation performance and can maintain high activity over a longer reaction time.

[0054] Simulated flue gas capture experiments have confirmed that the organosilicon quaternary ammonium salt catalyst provided by this invention is significantly superior to traditional MEA absorbents in terms of CO2 absorption capacity, absorption rate and final conversion rate, demonstrating excellent application potential.

[0055] Experimental Example 3: Analysis of the effect of improving the microstructure of mineralized products By measuring the specific surface area and pore size distribution of the solid products after the CO2 mineralization reaction, the unique effect of the product of this invention in inhibiting the formation of a dense passivation layer and constructing a loose and porous product layer is directly confirmed from the microstructural parameters. The specific steps are as follows: Two parallel CO2 mineralization experiments were set up: Control group: 1.0 g of calcium silicate powder was added to 100 mL of deionized water in a high-pressure reactor to obtain a mixture; Experimental group: Based on the control group, a catalyst product prepared in the example or comparative example with an amount equivalent to 1.0% of the mass of calcium silicate was added; CO2 was then introduced into the reactor to an initial pressure of 1.0 MPa, and the reaction was carried out at 60 °C with stirring at 300 rpm for 4 hours. After the reaction was completed, the solid residue was collected, washed repeatedly with deionized water until neutral, dried at 105 °C to constant weight, and ground to obtain a solid product for later use.

[0056] Test method: The specific surface area and pore size of the obtained solid product were analyzed using a physical adsorption instrument (Micromeritics ASAP 2460) and a low-temperature nitrogen adsorption-desorption method. The specific surface area was calculated using the BET (Brunauer-Emmett-Teller) equation, and the pore size distribution was calculated from the desorption curves using the BJH (Barrett-Joyner-Halenda) model. The results are shown in Table 3.

[0057] Table 3 Comparison of specific surface area and pore size parameters of solid products after mineralization reaction

[0058] As can be seen from Table 3, (1) specific surface area analysis: the experimental group (1.0% of Example 1) with 1.0% of the product of the present invention added had a BET specific surface area of ​​up to 35.2 m². 2 / g, which is the blank control group (8.5m 2 More than 4 times that of ( / g). Similarly, other examples also showed corresponding improvements, and the comparative example showed a significant decrease in data when the quaternization reaction was missing. This order of magnitude improvement strongly proves that the presence of the product of the present invention effectively prevents the dense accumulation of SiO2 particles and promotes the formation of a loose network structure with a huge surface area; (2) Pore size and pore volume analysis: Taking the experimental group (Example 1) as an example, the average pore size of its product reached 18.7nm, which is much larger than the 9.2nm of the blank group; its total pore volume was even higher than 0.020cm 3 / g increased significantly to 0.165cm 3 The increase in average pore size and the dramatic increase in total pore volume, from a mass transfer perspective, confirm that the product layer possesses more spacious and interconnected diffusion channels. This porous structure significantly reduces the diffusion of CO2 molecules and Ca... 2+ OH - Diffusion resistance of plasma in the product layer.

[0059] In summary, this invention, through its "targeted inhibition" mechanism, successfully transforms the traditional dense, low-porosity passivation layer into a porous structure with high specific surface area and large pore size. This structure ensures that the reaction interface remains exposed and the mass transfer channels are unobstructed, thus fundamentally solving the industry problem of reaction stagnation caused by the passivation layer. Microstructural characterization, including BET analysis, provides crucial microstructural evidence for the invention's superior performance in improving CO2 mineralization efficiency.

Claims

1. A method for preparing an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration, characterized in that, The steps include the following: (1) Hydrogen-terminated polydimethylsiloxane and allyl glycidyl ether were added to an organic solvent and subjected to a hydrosilylation reaction under the catalysis of a platinum catalyst. After the reaction was completed, the solvent was removed to obtain an epoxy-terminated polysiloxane intermediate. (2) The epoxy-terminated polysiloxane intermediate obtained in step (1) is added to an alcohol solvent, and a di-polyetheramine is added to carry out an ammonolysis ring-opening reaction to obtain a polyetheramine-terminated tertiary amine intermediate. (3) The polyetheramine-terminated tertiary amine intermediate obtained in step (2) is added to a polar solvent and a quaternization reagent is added to carry out the reaction. After the reaction is completed, the product is separated and purified to obtain an organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and storage.

2. The method for preparing the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration according to claim 1, characterized in that, The hydrogen content of the hydrogen-terminated polydimethylsiloxane in step (1) is 0.5-1.5%; the molar ratio of hydrogen in the Si-H bond to allyl glycidyl ether in the hydrogen-terminated polydimethylsiloxane is 1:1.05-1.

2.

3. The method for preparing the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration according to claim 1, characterized in that, The organic solvent mentioned in step (1) is toluene and / or isopropanol; the volume ratio of the organic solvent to the mass of the hydrogen-terminated polydimethylsiloxane is 15-40 mL: 1 g; The platinum catalyst contains 0.001-0.005% platinum by mass of hydrogen-terminated polydimethylsiloxane; the platinum catalyst is a 0.5-2% isopropanol chloroplatinate solution.

4. The method for preparing the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration according to claim 1, characterized in that, The temperature of the hydrosilylation reaction in step (1) is 60-85℃; the time of the hydrosilylation reaction is 4-8 hours; the hydrosilylation reaction is carried out under the protection of a protective gas, which is nitrogen or argon.

5. The method for preparing the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration according to claim 1, characterized in that, The alcohol solvent mentioned in step (2) is methanol or ethanol; the volume ratio of the alcohol solvent to the mass of the epoxy-terminated polysiloxane intermediate is 40-60 mL: 1 g; The binary polyetheramine is selected from one of polyetheramine D230, polyetheramine D400 or polyetheramine EDR-148; the molar ratio of the amino group in the binary polyetheramine to the epoxy group in the epoxy-terminated polysiloxane intermediate is 1-1.1:

1.

6. The method for preparing the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration according to claim 1, characterized in that, The temperature of the ammonium ring-opening reaction in step (2) is 50-80℃; the ammonium ring-opening reaction is carried out at a pressure of 0.2-0.5MPa; and the time of the ammonium ring-opening reaction is 3-10 hours. In step (2), after the ammonolysis ring-opening reaction is completed, excess reagents and solvents are removed to obtain a polyetheramine-terminated tertiary amine intermediate.

7. The method for preparing the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration according to claim 1, characterized in that, The polar solvent mentioned in step (3) is isopropanol or N,N-dimethylformamide; the volume ratio of the polar solvent to the mass of the polyetheramine-terminated tertiary amine intermediate is 60-100 mL: 1 g. The quaternizing agent is one of benzyl chloride, dimethyl sulfate, or chloromethane; the molar ratio of the quaternizing agent to the hydrogen in the Si-H bond of the hydrogen-terminated polydimethylsiloxane is 1-1.2:

1.

8. The method for preparing the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration according to claim 1, characterized in that, In step (1), the temperature of the reaction in step (3) is 70-85℃, and the reaction time is 5-10 hours; The separation and purification steps are as follows: the solvent is removed by vacuum distillation of the obtained reaction solution to obtain a crude product, and the crude product is recrystallized using a mixed solvent of ethyl acetate and n-hexane, wherein the volume ratio of ethyl acetate to n-hexane in the mixed solvent is 2-3:

1.

9. An organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

10. The application of the organosilicon quaternary ammonium salt catalyst for enhancing CO2 mineralization and sequestration as described in claim 9 in CO2 mineralization and capture.

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