Titanium modified attapulgite catalyst suitable for lysine potassium system, and preparation method and application thereof

Abstract

This invention discloses a titanium-modified attapulgite catalyst suitable for potassium lysine systems, its preparation method, and its application. The method involves adding attapulgite to a titanium sulfate solution, followed by ultrasonication and a single water bath heating to obtain a mixed solution. The pH is adjusted to 10.0±0.5, followed by a second water bath heating and aging to obtain a coprecipitate. This coprecipitate is then washed, dried, ground, and calcined to obtain the final product. This method is simple, low-cost, and solves the problems of existing CO2 desorption catalysts, which are mostly applicable to alkanolamine systems, unsuitable for amino acid salts, and suffer from complex preparation, poor stability, or easy degradation in solution. The prepared Ti-ATP catalyst exhibits highly efficient and stable catalytic desorption performance in potassium lysine systems.

Description

Technical Field

[0001] This invention belongs to the field of carbon capture technology, and relates to a titanium-modified attapulgite catalyst suitable for potassium lysine system, its preparation method and application. Background Technology

[0002] To address global climate change, controlling greenhouse gas emissions, primarily CO2, is crucial. Currently, capturing CO2 from industrial flue gas is a key pathway to achieving deep emission reduction, with technologies including absorption, adsorption, and membrane separation. Among these, chemical absorption (especially organic amine methods) is the most widely used due to its mature technology and high capture efficiency. However, its core bottleneck lies in the enormous energy consumption of the solvent regeneration process, accounting for approximately 60%-80% of the total operating cost. Studies generally agree that this high energy consumption stems from the high energy barriers and slow kinetics of the two strongly endothermic steps in the desorption process: carbamate decomposition and protonated amine deprotonation. Therefore, strategies to reduce regeneration energy consumption, besides developing novel solvents, hinge on enhancing the desorption process, such as by introducing catalysts to lower the reaction activation energy.

[0003] Among numerous novel absorbents, amino acid salt solutions (especially lysine) exhibit significant advantages over traditional alkanolamine systems. Compared to monoethanolamine (MEA), which is volatile, highly corrosive, and easily degraded, lysine possesses low volatility, low corrosivity, high antioxidant stability, and good biodegradability, making it more environmentally friendly and equipment-friendly. Studies have shown that lysine solutions at specific concentrations have CO2 absorption rates and capacities comparable to MEA, and demonstrate superior cycle stability and higher cycle load retention in multiple absorption-desorption tests. These characteristics make it a highly promising green alternative absorbent; however, the energy consumption issue of its rich-liquid regeneration remains to be addressed, and catalytic desorption is a feasible direction to overcome this bottleneck.

[0004] In the field of catalytic desorption, the core challenge lies in finding catalysts that combine high performance, low cost, and high stability. Compared to non-clay-based synthetic catalysts such as molecular sieves, metal-organic frameworks (MOFs), and solid superacids, which require complex synthesis and are costly, attapulgite (ATP) exhibits significant comprehensive advantages. Its core advantages stem first from its natural properties: extremely abundant reserves (my country accounts for over 60% of global reserves), simple mining and processing, and low price (costing only 10%-20% of conventional chemical silicon-aluminum raw materials), making large-scale industrial application economically feasible. Secondly, its nanofiber structure and abundant mesoporous system effectively disperse and stabilize active components when used as a catalyst support, enhancing metal-support interactions. More importantly, its surface acidity can be effectively controlled and significantly enhanced through simple modification methods such as impregnation, for example, by significantly increasing the number of strong acid sites and the Brønsted / Lewis (B / L) acid ratio, thereby optimizing its catalytic performance. Experimental studies have confirmed that appropriately modified ATP-based catalysts exhibit excellent performance in the desorption of CO2 from amine solutions, significantly increasing reaction rates and reducing energy consumption, while also demonstrating superior cycle stability and structural durability. Therefore, attapulgite, as a natural mineral material that is "tunable in performance, low in cost, widely available, and environmentally friendly," successfully circumvents the common bottlenecks of synthetic catalysts in terms of preparation complexity, high cost, and long-term stability, providing a highly attractive and practical material platform for developing novel, efficient desorption catalysts suitable for industrial carbon capture.

[0005] Chinese patent CN121314658A discloses a "bimetallic catalyst for promoting CO2 absorption-desorption cycle in alkanolamine solutions, its preparation method, and its application." This catalyst uses ordered mesoporous molecular sieve MCM-41 as a support and simultaneously loads zirconium sulfate (Zr(SO4)2) and copper acetylacetone (Cu(acac)2) as bimetallic active components via a one-step hydrothermal method. Utilizing the synergistic effect of zirconium and copper, and the introduced sulfate ions enhancing surface acidity, it catalyzes the decomposition of bicarbonate and lowers the CN bond breaking energy barrier. In a 30% MEA solution, it increases desorption by 21%, reduces relative heat load by approximately 26%, and retains over 90% of its activity after 5 cycles. However, the preparation of this catalyst relies on precisely controlled hydrothermal synthesis (120-140°C, 20-28h) and subsequent high-temperature calcination (500-600°C), which is a lengthy process. Furthermore, the synthesis of MCM-41 molecular sieves itself requires a template agent (such as CTAB) and strict pH control, making the process cumbersome and costly. In addition, the precise ratio of the bimetallic components (Zr to Cu oxide mass ratio 0.5:1-2:1) significantly affects performance, requiring high control standards, and the long-term stability of the support in highly alkaline amine solutions also faces challenges.

[0006] Chinese patent CN202510558731.6 discloses "Application of a Zirconium Hydrogen Phosphate Catalyst in Carbon Dioxide Desorption". This technology directly uses layered zirconium hydrogen phosphate (ZrHP) as a catalyst, utilizing its abundant acidic sites (including strong acid sites) to promote CO2 desorption. The ZrHP catalyst does not require a complex loading process and can be separated and regenerated from the amine solution through simple centrifugation (6000-10000 rpm), avoiding the high-temperature calcination step. It exhibits good performance in various amine solutions (such as MEA, DEA, DMEA, etc.), with desorption capacity increased by up to 94% and energy consumption reduced by approximately 48%. Its advantages include readily available raw materials, low cost, and simple regeneration. However, this catalyst is a homogeneous acid catalyst, and its strong acidity may lead to amine degradation or equipment corrosion. Its layered structure may dissolve or aggregate during long-term thermal cycling, gradually covering the active sites. Furthermore, its catalytic performance is highly dependent on crystal orientation (the proportion of the 002 crystal facet needs to be controlled between 45% and 80%), limiting its applicability to various amine systems. In addition, while centrifugal regeneration is energy-efficient, it increases operational steps and equipment requirements, posing challenges for integration into continuous industrial plants.

[0007] Chinese patent CN202510443910.5 discloses "Preparation of multi-component layered double hydroxide-derived composite metal oxides and their application in the catalytic desorption of CO2 from amine solutions." This catalyst synthesizes nickel-aluminum layered double hydroxide precursors via co-precipitation, followed by calcination (300-600°C) to obtain a mesoporous composite metal oxide (LDO). It possesses abundant surface hydroxyl groups and a large specific surface area (e.g., Ni4Al1-LDO can reach 91.1 μm²). 2 The method ( / g) is beneficial for reactant adsorption, and can increase the CO2 desorption rate by 86% at 88°C, with stable activity after 5 cycles. The acidity and structure of the catalyst can be controlled by adjusting the types and ratios of divalent / trivalent metals (such as Ni / Al, Co / Al, Mn / Al), offering considerable flexibility. However, the preparation of the hydrotalcite-like precursor requires a long hydrothermal reaction (6-15 h) and aging (15-24 h), resulting in a long overall cycle; the calcination process may lead to partial pore collapse or sintering of active components; while the introduction of multiple metals improves performance, it also increases the complexity and cost of synthesis, and the synergistic mechanism of different metal combinations still needs further optimization to achieve a balance between activity, stability, and economy.

[0008] In summary, while existing high-efficiency CO2 desorption catalysts each possess their advantages, their development is primarily focused on traditional alkanolamine systems, generally suffering from complex preparation processes, high costs, insufficient cycle stability, or susceptibility to solvent degradation in strongly acidic environments. Compared to alkanolamines, novel amino acid salt absorbents, represented by lysine, offer advantages such as higher CO2 loading capacity, lower volatility and degradation rate, better antioxidant properties, and environmental friendliness, making them highly promising alternatives. However, highly efficient desorption catalysts suitable for this more alkaline, viscosity-rich liquid system remain relatively scarce. Summary of the Invention

[0009] To address the problems existing in the prior art, this invention provides a titanium-modified attapulgite catalyst suitable for the potassium lysine system, its preparation method, and its application. This solves the problems that existing CO2 desorption catalysts are mostly designed for traditional alkanolamine systems, and generally suffer from complex preparation, high cost, poor stability, or easy degradation by strong acids. Furthermore, there is a lack of efficient, stable, and low-cost catalysts suitable for novel amino acid salt systems.

[0010] This invention is achieved through the following technical solution: A method for preparing titanium-modified attapulgite catalysts suitable for potassium lysine systems includes the following steps: S1: Add attapulgite powder to an aqueous solution of titanium sulfate, sonicate to obtain a Ti-ATP mixture, and subject the Ti-ATP mixture to a water bath heating and stirring treatment to obtain a Ti-ATP mixed suspension. S2: Adjust the pH of the Ti-ATP mixed suspension to 10.0±0.5, then perform a second water bath heating and stirring treatment, and after standing and aging, obtain Ti-ATP coprecipitate; S3: The Ti-ATP coprecipitate is washed, dried, ground and calcined to obtain the titanium-modified attapulgite catalyst suitable for the potassium lysine system, i.e., the Ti-ATP composite catalyst.

[0011] Preferably, the mass ratio of the attapulgite powder to titanium sulfate is 1:(0.5~3).

[0012] Preferably, the attapulgite powder is 300 mesh, and the ultrasonic time is 20-30 minutes.

[0013] Preferably, the temperature of the first water bath heating and stirring treatment is 50~60℃, and the time is 8~10h.

[0014] Preferably, the secondary water bath heating and stirring treatment is carried out at a temperature of 50~60℃ for 4~5 hours; the static aging time is 10~12 hours. Preferably, in step S3, the pH value is 7-8.

[0015] Preferably, in step S3, during the calcination treatment, the heating rate is 2~3℃ / min, the holding temperature is 500℃, and the holding time is 4~6h.

[0016] A titanium-modified attapulgite catalyst suitable for potassium lysine systems was prepared by the method described above.

[0017] The above describes the application of a titanium-modified attapulgite catalyst in the lysine potassium system for CO2 desorption.

[0018] Preferably, the amount of titanium-modified attapulgite catalyst added to the potassium lysine system is 2.5~10 g / L.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a method for preparing titanium-modified attapulgite catalysts suitable for potassium lysine systems, effectively solving the problems of complex preparation, high cost, and poor stability of existing CO2 desorption catalysts. Firstly, attapulgite is abundant and inexpensive, significantly reducing raw material costs as a support and overcoming the shortcomings of traditional catalysts that rely on expensive materials or complex synthesis. Secondly, this method utilizes the unique nanofiber structure and high specific surface area of ​​attapulgite to achieve high dispersion and stable anchoring of the titanium active components, enhancing the metal-support interaction and thus improving the mechanical and chemical stability of the catalyst, avoiding the loss of active components or collapse of the support structure under strongly acidic conditions. Furthermore, this process involves conventional chemical treatment steps such as water bath heating, pH adjustment, and calcination, making the process simple and convenient to operate, avoiding the need for high temperature, high pressure, or special equipment, and greatly simplifying the preparation process. The resulting Ti-ATP composite catalyst possesses both acid-base synergistic catalytic sites and is particularly suitable for novel amino acid salt systems such as potassium lysine. It not only improves CO2 desorption efficiency but also solves the technical problems of poor compatibility of traditional catalysts in amino acid salt systems and easy solvent degradation, thus achieving efficient, stable, and low-cost CO2 capture and regeneration.

[0020] Furthermore, the mass ratio of attapulgite powder to titanium sulfate is 1:(0.5~3). By controlling the mass ratio of attapulgite powder to titanium sulfate to 1:(0.5~3), it is possible to ensure that the titanium active component is highly dispersed on the surface of the attapulgite support, avoiding the agglomeration of active components and blockage of pores. This ratio range optimizes the distribution of acid and base sites on the catalyst surface, enabling the acidic sites (Ti) and the basic sites (ATP) of the support to achieve the best synergistic effect. Thus, while ensuring high desorption activity of the catalyst, it avoids raw material waste and achieves the best balance between cost and performance.

[0021] Furthermore, the attapulgite powder is 300 mesh, and the ultrasonication time is 20-30 minutes. This effectively utilizes the cavitation effect of ultrasound to open the nanocrystal bundles of attapulgite, fully exposing its internal channels and surface active sites. This not only promotes the penetration and adsorption of titanium sulfate solution into the carrier channels and improves the uniformity of the load, but also avoids carrier structure damage or increased energy consumption caused by excessively long ultrasonication time, laying the foundation for the subsequent formation of highly dispersed active centers.

[0022] Furthermore, the initial water bath heating and stirring treatment is conducted at a temperature of 50-60°C for 8-10 hours, providing suitable activation energy for the diffusion of titanium ions into the attapulgite channels and accelerating the establishment of ion exchange and adsorption equilibrium. This condition ensures that the active titanium components can penetrate deep into the support for loading, rather than merely adhering to the surface, thereby significantly improving the loading efficiency and dispersion of the active components. Furthermore, the secondary water bath heating and stirring treatment is carried out at a temperature of 50-60℃ for 4-5 hours; the static aging time is 10-12 hours. This promotes the directional growth and crystallization of precipitates on the support surface and repairs lattice defects using the Ostwald ripening mechanism. This process enhances the binding force (anchoring effect) between the active component and the support, preventing the loss of active components during subsequent washing or use, thereby improving the mechanical stability and cycle life of the catalyst.

[0023] Furthermore, in step S3, the pH value is 7-8, which can effectively remove residual sulfate and other impurity ions from the co-precipitation process, preventing impurities from poisoning the active sites of the catalyst, and also prevent the active components from being dissolved or the crystal structure of attapulgite from being damaged due to excessively high acidity or alkalinity of the washing solution, thereby ensuring the purity and structural integrity of the final product.

[0024] Furthermore, in step S3, during the calcination treatment, the heating rate is 2~3℃ / min, the holding temperature is 500℃, and the holding time is 4~6h. This effectively prevents catalyst particle breakage or pulverization caused by rapid moisture evaporation. Simultaneously, this calcination temperature promotes the complete decomposition of the precursor and its transformation into a highly catalytically active crystalline phase, enhancing the metal-support interaction. It also avoids sintering and specific surface area collapse caused by excessively high temperatures, ensuring the catalyst's high activity and thermal stability.

[0025] When applying the aforementioned titanium-modified attapulgite catalyst to CO2 desorption in a potassium lysine system, the optimal addition amount of titanium-modified attapulgite catalyst is 2.5~10 g / L. This ensures sufficient active sites to significantly improve the desorption rate while avoiding problems such as increased solution viscosity, impaired gas-liquid mass transfer, or sedimentation due to excessively high catalyst concentration. This concentration range achieves the optimal match between catalytic efficiency and hydrodynamic performance, ensuring operational stability and economy in industrial applications. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The XRD patterns of the catalyst and the ATP support prepared in Example 2 of this invention are shown. Figure 2 The N2 adsorption-desorption isotherm of the catalyst and ATP carrier prepared in Example 2 of this invention; Figure 3 The pore size distribution diagrams of the catalyst and the ATP support obtained in Example 2 of this invention are shown. Figure 4 The NH3-TPD curves of the catalyst and the ATP support prepared in Example 2 of this invention are shown. Detailed Implementation

[0028] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0029] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0030] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0031] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0032] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0033] This invention provides a method for preparing titanium-modified attapulgite catalysts suitable for potassium lysine systems, comprising the following steps: S1: Add attapulgite powder (ATP) to an aqueous solution of titanium sulfate, sonicate to obtain a Ti-ATP mixture, and subject the Ti-ATP mixture to a water bath heating and stirring treatment to obtain a Ti-ATP mixed suspension. The attapulgite powder is 300 mesh. The mass ratio of attapulgite powder to titanium sulfate is 1:(0.5~3); The above process is as follows: Weigh 300-mesh attapulgite powder and titanium sulfate according to the mass ratio of attapulgite and titanium metal, with a mass ratio of 1:(0.5~3). First, dissolve titanium sulfate in 100 mL of deionized water and stir evenly to prepare a solution. Then, add attapulgite powder and sonicate for 25~30 min. Finally, stir to obtain Ti-ATP mixture. Attapulgite powder is a natural nanofiber-like magnesium aluminum silicate mineral. Attapulgite powder has a typical dioctahedral structure, which is more suitable for loading metals. It possesses advantages such as a permanent negative charge, high specific surface area, and strong ion exchange capacity, enabling efficient anchoring of metal ions and achieving highly dispersed loading. Furthermore, it has numerous acidic sites on its surface, which can synergistically catalyze metals. The attapulgite powder used in this invention can be derived from the Huangni Mountain mine in Xuyi County, Jiangsu Province, my country.

[0034] The temperature of the first water bath heating and stirring treatment is 50~60℃, and the time is 8~10h; S2: Adjust the pH of the Ti-ATP mixed suspension to 10.0±0.5, then perform a second water bath heating and stirring treatment, and after standing and aging, obtain Ti-ATP coprecipitate; The pH value of the Ti-ATP mixed suspension was adjusted using NaOH solution, and the concentration of the NaOH solution was 2M. The secondary water bath heating and stirring treatment is carried out at a temperature of 50~60℃ for 4~6 hours; The aging time is 10-12 hours; Specifically, when adjusting the pH value, the system was continuously stirred at a stirring speed of 500 rpm, and 2M NaOH solution was slowly added dropwise using an alkaline burette to adjust the pH to 10.0±0.5. The pH was monitored in real time using a calibrated pH meter. After the pH value was adjusted, the system was heated in a water bath at 60℃ and magnetically stirred for 4 hours. Then, it was allowed to stand for 12 hours to age, and finally Ti-ATP coprecipitate was obtained. S3: The Ti-ATP coprecipitate is washed, dried, ground and calcined to obtain the titanium-modified attapulgite catalyst suitable for the potassium lysine system, i.e., the Ti-ATP composite catalyst.

[0035] Specifically, the Ti-ATP coprecipitate is washed with hot deionized water to remove Na+. + SO4 2- To remove impurities such as impurities and byproducts like Na₂SO₄, the washing process aims to prevent clogging of pores, covering of active sites, and interference with the calcined product. Finally, conductivity and pH tests are performed to ensure that impurities and excess acid or alkali have been completely removed. Washing is terminated when the pH reaches 7-8.

[0036] The drying temperature is 100~120℃ and the time is 10~12h. That is, during the drying process, the filter cake obtained after washing is placed in an oven at 100~120℃ and dried for 10~12h. During the calcination treatment, the heating rate was 2℃ / min, the holding temperature was 450~500℃, and the holding time was 4~6h. After drying, the powder was ground into 300 mesh powder, and then heated to 450~500℃ in a muffle furnace at a heating rate of 2℃ / min and held for 3~4h to finally obtain the Ti-ATP composite catalyst.

[0037] In addition, the present invention also discloses a titanium-modified attapulgite catalyst suitable for potassium lysine systems prepared by the above method.

[0038] Meanwhile, the present invention also verified the performance of the titanium-modified attapulgite catalyst prepared above for CO2 desorption (regeneration) in potassium lysine solution and the principle of CO2 loading (α) determination by the following method.

[0039] Among them, (1) the principle of desorption performance testing, namely, simulating the regeneration process, is as follows: Simulated rich solution: First, a "rich solution" that has absorbed a large amount of CO2 is prepared, with a CO2 loading (α) of 1.3 ± 0.02 mol CO2 / mol, that is, 1 mole of potassium lysine (absorbent) absorbs 1.3 ± 0.02 mol of CO2, simulating the solution at the bottom of an industrial absorption tower; The potassium lysine solution here can be a 2 mol / L potassium lysine solution prepared by reacting lysine and potassium hydroxide in a 1:1 molar ratio to prepare a potassium lysine solution with a final concentration of 2 mol / L.

[0040] Thermal desorption (regeneration): 40 mL of the rich solution was placed in a 100 mL three-necked flask with a built-in magnetic stirrer and heated in an oil bath at 110 °C. This simulates the industrial process of breaking the chemical bonds between amines and CO2 through heating, forcing the release of CO2.

[0041] During the analysis process, the system simultaneously purges the tube with N2 and connects a thermometer and a 0±1℃ cooling circulation condenser.

[0042] Here, N2 (nitrogen) is introduced as a carrier gas. N2 does not participate in the reaction, but it lowers the partial pressure of CO2 in the gas phase, shifting the chemical equilibrium towards desorption and "blowing" out the released CO2. When the CO2-rich solution is heated, CO2 is released from the solution (desorption). The introduction of N2, as an inert gas, "blown" this released CO2 out of the reaction flask and through a pipeline to a downstream detector (such as an infrared analyzer) to measure the concentration and total amount of CO2. Furthermore, according to the principle of chemical equilibrium, the lower the partial pressure of CO2 in the gas phase, the easier it is for CO2 to escape from the liquid phase. Introducing N2 dilutes CO2, lowering its partial pressure, thereby accelerating the desorption process and making the regeneration reaction more complete. It also prevents oxygen in the air from oxidizing and degrading the lysine solution at high temperatures.

[0043] The thermometer connection enabled real-time monitoring of the temperature during the desorption process, as the CO2 desorption rate is highly sensitive to temperature. The experiment needed to be strictly controlled at 110±1℃ (oil bath temperature), and the thermometer was used to monitor the actual temperature of the reaction solution in real time to ensure the accuracy of the experimental conditions.

[0044] Furthermore, due to the high reaction temperature of 110℃, a large amount of water (solvent) in the solution will evaporate. A condenser is used to circulate a 0℃ coolant (usually an ice-water mixture) to condense the evaporated water vapor back into liquid, which then flows back into the reaction flask, effectively preventing solvent loss. Without a condenser, the water would continuously evaporate, leading to a decrease in solution volume and an increase in concentration, resulting in significant errors in experimental data. Moreover, if water vapor enters the downstream gas lines or detectors, it will condense into water, clogging the lines and potentially damaging the infrared analyzer.

[0045] Real-time monitoring: The volume fraction of CO2 in the outlet gas is monitored in real time using an infrared analyzer. By analyzing the CO2 concentration change curve over time, the desorption rate and total desorption amount can be calculated, thereby determining whether the catalyst is effective, i.e., whether it accelerates the CO2 release rate.

[0046] (2) The principle of CO2 loading (α) determination, namely hydrochloric acid expulsion titration, is as follows: Acid-base reaction expulsion: Using a strong acid (HCl) to react with carbonates / carbamates in the solution to forcibly replace (expel) the bound CO2. Quantitative acquisition of gas loading: The released CO2 gas displaces the indicator liquid (usually water or oil) in the titration apparatus. The change in the indicator liquid level before and after the reaction is measured. ), and deduct the effect of changes in the volume of hydrochloric acid solution ( The volume of CO2 gas generated can be obtained by calculating (273.15 / (273.15+T)) to convert the gas volume at the experimental temperature (T℃) to the volume at the standard state (0℃) to ensure accuracy, as the gas volume is affected by temperature. Finally, by comparing the measured number of moles of CO2 with the number of moles of potassium lysine in the solution, the number of moles of CO2 bound per mole of potassium lysine is calculated, i.e., the loading α. This is a key indicator for evaluating the performance of the absorbent. Specifically, the loading α is:

[0047] In the formula, Refers to the molar volume of a gas. Refers to amino acid concentration (mol / L). This refers to the volume (mL) of the amino acid test reagent. Refers to real-time temperature (°C).

[0048] The catalyst was characterized using the following methods: 1) X-ray diffraction characterization (XRD). XRD was performed on a SmartLab (Rigaku) ​​equipped with Cu Kα radiation (U=40 kV, I=30 mA), with the scanning angle (2θ) set in the range of 5° to 95° and the scanning speed at 10 ºC / min.

[0049] 2) Fully automated specific surface area and porosity characterization (BET). The structural characteristics of the samples were determined by nitrogen physisorption at liquid nitrogen temperature using a micromechanical device (model ASAP 2460). Surface area and pore size distribution were determined by the Brunauer-Emmett-Teller (BET) and Barrete-Joynere-Halenda (BJH) methods, respectively.

[0050] 3) Temperature-programmed reduction characterization (NH3-TPR). The NH3-TPR experiment was conducted on a BELCAT II instrument manufactured by Microtrac BEL.

[0051] This invention discloses a method for preparing a titanium-modified attapulgite catalyst suitable for potassium lysine systems, and its application in the CO2 desorption-absorption process of potassium lysine solutions. The titanium-modified attapulgite (Ti-ATP) catalyst prepared by this invention exhibits unique advantages in the reaction pathway when applied to a potassium lysine (K-Lys) solution CO2 capture system. Compared to traditional alkanolamine systems, potassium lysine itself is environmentally friendly, biodegradable, non-degradable, and has low volatility. In this system, the Lewis acidic sites provided by titanium species can efficiently catalyze the decomposition of amino acid salt-bicarbonate intermediates, directly accelerating CO2 desorption kinetics; while the basic sites on the ATP carrier surface can react with K... + A reversible interaction is generated, reducing the desorption enthalpy change without affecting the absorption capacity, thereby achieving acid-base synergistic catalysis and significantly reducing regeneration energy consumption. The preparation process of this catalyst is simple, economical, and environmentally friendly. Using an impregnation-precipitation method with inexpensive titanium salts as precursors, titanium species can be uniformly loaded onto the surface of natural attapulgite by adjusting the pH value. ATP is widely available and inexpensive; the entire process requires no complex equipment or high-temperature, high-energy-consuming steps; wastewater treatment after washing is simple, meeting the requirements of large-scale production and a circular economy, and is particularly suitable for use with amino acid salt capture systems, which already possess environmentally friendly properties. Moreover, the catalyst prepared by this invention has a stable structure and good durability. The nanofiber structure and high specific surface area of ​​ATP provide strong anchoring sites for titanium species, and the formed Ti-O-Si bonds significantly enhance the mechanical and chemical stability of the catalyst. In alkaline amino acid salt solutions, this catalyst exhibits excellent resistance to dissolution, high activity retention after recycling, and overcomes the problem of catalyst deactivation due to the adhesion of amine degradation products in alkanolamine systems, demonstrating promising prospects for industrial applications. This invention proposes a catalyst using natural attapulgite as a support and loaded with titanium active components, specifically for catalyzing the desorption of CO2 from potassium lysine solution. This catalyst utilizes the abundant pores and surface hydroxyl groups of attapulgite to stably disperse titanium species and provide suitable acidic sites. Its preparation employs a simple impregnation-calcination method, which is concise, uses inexpensive raw materials, avoids complex synthesis steps, and combines high activity, strong stability, and good economic efficiency, providing a targeted solution for the efficient and low-carbon regeneration of high-performance amino acid salt absorbents.

[0052] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0053] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0054] Example 1 A titanium-modified attapulgite catalyst suitable for potassium lysine systems is prepared as follows: 300-mesh attapulgite and titanium sulfate were mixed at a 1:1 mass ratio. Titanium sulfate was first dissolved in 100 mL of deionized water, and then attapulgite powder was added followed by ultrasonic treatment for 30 minutes. The resulting Ti-ATP mixture was heated in a 60℃ water bath and magnetically stirred for 8 hours. Then, 2M NaOH solution was added dropwise at 500 rpm to adjust the pH to 10.0 ± 0.5. Heating and stirring continued at 60℃ for 4 hours, followed by aging at rest for 12 hours to obtain a coprecipitate. The coprecipitate was thoroughly washed, dried at 100℃ for 12 hours, ground into powder, and then calcined at 500℃ for 3 hours at a rate of 2℃ / min to obtain the Ti-ATP composite catalyst.

[0055] Performance testing of the Ti-ATP composite catalyst: Weigh 0.3 g of the prepared catalyst sample using an analytical balance and place it in a 100 mL three-necked flask. Then add the CO2 absorption loading amount. α 40 mL of rich solution, achieving a concentration of 1.3 ± 0.02 mol CO2 / mol AAS, was placed in a three-necked flask reaction apparatus, and its airtightness was checked. The flask contained a magnetically stirred liquid. N2 was introduced through one end to purge the desorbed gas, while a thermometer was connected to the other end to monitor the temperature change of the desorbed liquid in real time. A condenser was connected to the middle port to condense and reflux the vapor, minimizing liquid loss. The condenser contained a cryogenic liquid at 0 ± 1 °C continuously supplied by a cooling circulating water pump. The upper outlet of the condenser was connected to a drying tube containing anhydrous calcium chloride for drying. The dried gas was then passed through an infrared gas analyzer to analyze the real-time CO2 volume fraction. After ensuring the apparatus was properly sealed, the three-necked flask containing the rich solution was placed in an oil bath and heated to 110 ± 1 °C, while simultaneously recording the CO2 volume fraction in the outlet gas.

[0056] Data analysis and processing showed that under these conditions, the maximum real-time desorption rate of CO2 could reach 122 mL / min, which was 90.625% higher than that of the blank group. The cumulative desorption volume of CO2 in 90 min could reach 1900 mL, which was 35% higher than that of the blank group. The rate ratio reached 1.58 in the first 20 min.

[0057] Example 2 The difference between this embodiment and Example 1 is that the mass ratio of attapulgite to titanium sulfate is 2:1 when preparing the Ti-ATP composite catalyst.

[0058] Performance testing of the catalyst: The testing process in this embodiment is the same as in Example 1. Under the same test conditions, the composite catalyst prepared in this embodiment can achieve a maximum real-time desorption rate of CO2 of 97.5 mL / min, which is 52.3% higher than the blank group. The cumulative desorption volume of CO2 in 90 min can reach 1778 mL, which is 26.2% higher than the blank group. The rate ratio in the first 20 min reaches 1.42.

[0059] Example 3 The difference between this embodiment and Example 1 is that the mass ratio of attapulgite to titanium sulfate is 2:3 when preparing the Ti-ATP composite catalyst.

[0060] Performance testing of the catalyst: The testing process in this embodiment is the same as in Example 1. Under the same conditions, the composite catalyst prepared in this embodiment can achieve a maximum real-time desorption rate of CO2 of 109 mL / min, which is 70.3% higher than the blank group. The cumulative desorption volume of CO2 in 90 min can reach 1858.7 mL, which is 32% higher than the blank group. The rate ratio in the first 20 min reaches 1.49.

[0061] Example 4 The difference between this embodiment and Example 1 is that the mass ratio of attapulgite to titanium sulfate is 1:2 when preparing the Ti-ATP composite catalyst.

[0062] Performance testing of the catalyst: The testing process in this embodiment is the same as in Example 1. Under the same conditions, the composite catalyst prepared in this embodiment can achieve a maximum real-time desorption rate of CO2 of 90.4 mL / min, which is 41.25% higher than the blank group. The cumulative desorption volume of CO2 in 90 min can reach 1732 mL, which is 23% higher than the blank group. The rate ratio in the first 20 min reaches 1.35.

[0063] Example 5 The difference between this embodiment and Example 1 is that the mass ratio of attapulgite to titanium sulfate is 1:3 when preparing the Ti-ATP composite catalyst.

[0064] Performance testing of the catalyst: The testing process in this embodiment is the same as in Example 1. Under the same conditions, the composite catalyst prepared in this embodiment can achieve a maximum real-time desorption rate of CO2 of 85 mL / min, which is 32.8% higher than the blank group. The cumulative desorption volume of CO2 in 90 min can reach 1679 mL, which is 19.24% higher than the blank group. The rate ratio in the first 20 min reaches 1.27.

[0065] Comparative Example 1 The difference between the analysis process and Example 1 is that no catalyst is added; that is, a desorption blank experiment is performed without adding a catalyst. This comparative example serves as the blank group.

[0066] Data analysis and processing show that under these conditions, the maximum real-time desorption rate of CO2 can reach 64 mL / min, the cumulative desorption volume of CO2 in 90 min can reach 1408 mL, and the rate ratio in the first 20 min is 1.

[0067] Example 6 A method for preparing titanium-modified attapulgite catalysts suitable for potassium lysine systems includes the following steps: S1: Add 300-mesh attapulgite powder (ATP) to an aqueous solution of titanium sulfate, wherein the mass ratio of attapulgite powder to titanium sulfate is 1:0.5. After sonication for 25 min, a Ti-ATP mixture is obtained. The Ti-ATP mixture is then subjected to a water bath heating and stirring treatment at 50°C for 10 h to obtain a Ti-ATP mixed suspension. S2: The pH of the Ti-ATP mixed suspension was adjusted to 10.0±0.5 using NaOH solution, and then subjected to a second water bath heating and stirring treatment at 50℃ for 5h. After standing and aging for 10h, Ti-ATP coprecipitate was obtained. S3: The Ti-ATP coprecipitate was washed until the pH value was 7, then dried at 100℃ for 12h, ground into 300 mesh powder, and finally heated to 500℃ in a muffle furnace at a heating rate of 2℃ / min and held for 3h to obtain the Ti-ATP composite catalyst.

[0068] Performance test results: Under these conditions, the maximum real-time desorption rate of CO2 reached 95 mL / min, an increase of approximately 48% compared to the control group, and the cumulative desorption volume of CO2 reached 1750 mL in 90 min. This demonstrates that it still exhibits good catalytic activity at the lower limit of protection.

[0069] Example 7 A method for preparing titanium-modified attapulgite catalysts suitable for potassium lysine systems includes the following steps: S1: Add 300-mesh attapulgite powder (ATP) to an aqueous solution of titanium sulfate, wherein the mass ratio of attapulgite powder to titanium sulfate is 1:3. After sonication for 30 min, a Ti-ATP mixture is obtained. The Ti-ATP mixture is then subjected to a water bath heating and stirring treatment at 60°C for 8 h to obtain a Ti-ATP mixed suspension. S2: The pH of the Ti-ATP mixed suspension was adjusted to 10.0±0.5 using NaOH solution, and then subjected to a second water bath heating and stirring treatment at 60℃ for 4 hours. After standing and aging for 12 hours, Ti-ATP coprecipitate was obtained. S3: The Ti-ATP coprecipitate was washed until the pH value was 8, then dried at 120℃ for 10h, ground into 300 mesh powder, and finally heated to 500℃ in a muffle furnace at a heating rate of 2℃ / min and held for 4h to obtain the Ti-ATP composite catalyst.

[0070] Performance test results: Under these conditions, the maximum real-time desorption rate of CO2 reached 86 mL / min, an increase of approximately 34% compared to the control group, and the cumulative desorption volume of CO2 reached 1680 mL in 90 minutes. This demonstrates that catalytic activity is still present at the upper limit of the protection range, although a downward trend has emerged.

[0071] Example 8 A method for preparing titanium-modified attapulgite catalysts suitable for potassium lysine systems includes the following steps: S1: Add 300-mesh attapulgite powder (ATP) to an aqueous solution of titanium sulfate, wherein the mass ratio of attapulgite powder to titanium sulfate is 1:2. After sonication for 28 min, a Ti-ATP mixture is obtained. The Ti-ATP mixture is then subjected to a water bath heating and stirring treatment at 60°C for 8 h to obtain a Ti-ATP mixed suspension. S2: The pH of the Ti-ATP mixed suspension was adjusted to 10.0±0.5 using NaOH solution, and then subjected to a second water bath heating and stirring treatment at 55℃ for 5h. After standing and aging for 11h, Ti-ATP coprecipitate was obtained. S3: The Ti-ATP coprecipitate was washed until the pH value was 7, then dried at 110℃ for 11h, ground into 300 mesh powder, and finally heated to 500℃ in a muffle furnace at a heating rate of 2℃ / min and held for 3.5h to finally obtain the Ti-ATP composite catalyst.

[0072] Example 9 An application method for titanium-modified attapulgite catalysts in potassium lysine systems is as follows: Weigh 0.4 g (corresponding to 40 mL of solution, i.e. 10 g / L) of the catalyst sample prepared in Example 1 using an analytical balance and place it into a 100 mL three-necked flask. Then add 40 mL of rich solution with a CO2 absorption loading α of 1.3 ± 0.02 mol CO2 / mol AAS (subsequent test steps are the same as in Example 1).

[0073] Performance test results: Under these conditions, the maximum real-time desorption rate of CO2 can reach 120 mL / min, and the cumulative desorption volume of CO2 in 90 min can reach 1890 mL. No significant sedimentation or increase in viscosity was observed in the solution, proving that it remains effective and stable at a concentration of 10 g / L.

[0074] Example 10 An application method for titanium-modified attapulgite catalysts in potassium lysine systems is as follows: Weigh 0.1 g (corresponding to 40 mL of solution, i.e. 2.5 g / L) of the catalyst sample prepared in Example 1 using an analytical balance and place it into a 100 mL three-necked flask. Then add 40 mL of rich solution with a CO2 absorption loading α of 1.3 ± 0.02 mol CO2 / mol AAS (subsequent test steps are the same as in Example 1).

[0075] Performance test results: Under these conditions, the maximum real-time desorption rate of CO2 reached 72 mL / min, which was approximately 12.5% ​​higher than that of the control group. This demonstrates that a positive catalytic effect can still be achieved even at a dosage as low as 2.5 g / L.

[0076] The effects of the Ti-ATP composite catalysts prepared in Examples 1-5 of this invention on CO2 desorption are shown in Table 1. Table 1 shows that the Ti-ATP composite catalyst exhibits the best catalytic effect on CO2 desorption when the mass ratio of attapulgite to titanium sulfate is 1:1. Furthermore, the data reveals that excessive titanium loading actually reduces the catalytic effect. This is because excess titanium leads to a decrease in catalytic performance, mainly due to its disruption of the catalyst's micro / nano structure and surface chemical balance. Physically, excess titanium species clog the support pores, resulting in a sharp reduction in specific surface area and increased mass transfer resistance. Chemically, excess titanium covers the active centers, causing an imbalance in the distribution of acidic sites and forming an inert TiO2 coating layer. This weakens the contact between the active component and the reactants, as well as the redox cycle, thereby inhibiting the overall catalytic efficiency.

[0077] Figure 1 Table 2 shows the XRD patterns of the catalyst and ATP support prepared in Example 2 of this invention. Table 2 contains the XRD lattice analysis data of the catalyst and ATP support prepared in Example 2 of this invention. Figure 1 As shown in Table 2, the support used in the experiment was well-crystallized pure attapulgite (ATP), whose strongest diffraction peak was located at 2θ=30.94° with a relative intensity as high as 3347. The grain size, estimated by the Scherrer formula, ranged from 4.9 to 33.6 nm, and its structure remained stable after calcination at 500℃ for 3 h, proving that it is an ideal support with excellent thermal stability. After titanium modification, the structure of the obtained 1 / 1Ti-ATP catalyst underwent profound changes: its strongest diffraction peak shifted significantly to 2θ=26.63°, and the corresponding interplanar spacing d increased from 0.2888 nm to 0.3345 nm, confirming that the introduction of titanium led to lattice expansion. At the same time, the diffraction peaks showed abnormal broadening (e.g., the full width at half maximum (FWHM) at 54.85° reached 2.256°), and the calculated apparent grain size was extremely small. This is mainly due to the high lattice strain caused by the strong interaction between titanium and the support. Furthermore, the characteristic peak (30.94°) attributed to carbonate impurities essentially disappeared, and no crystalline TiO2 phase was detected in the full spectrum, indicating that the modification process simultaneously purified the support and allowed titanium species to exist in a highly dispersed amorphous form. This demonstrates the successful construction of a Ti / ATP composite material with strong interfacial interactions, high strain, and a pure surface. This structure facilitates the formation of abundant surface acidic sites (especially Brønsted acids) and active interfaces, laying a crucial structural foundation for enhancing its activity and stability in catalyzing CO2 desorption in the potassium lysine system.

[0078] Figure 2 This is the N2 adsorption-desorption isotherm of the catalyst and ATP support prepared in Example 2 of this invention. Figure 3Table 3 shows the pore size distribution of the catalyst and ATP support prepared in Example 2 of this invention. Table 4 shows the BET structure characterization data of the catalyst and ATP support prepared in Example 2 of this invention. Figures 2-3 As shown in Table 3, this invention successfully achieved a revolutionary optimization of the attapulgite (ATP) support structure through titanium modification. Compared to the original ATP, the BET specific surface area of ​​the titanium-supported catalyst (1 / 1 Ti-ATP) increased by 18.2% (to 148.01 m²). 2 / g), and more importantly, its pore structure underwent a fundamental transformation: the proportion of mesopores jumped dramatically from 62.4% to 90.6%, while the total pore volume surged by 40.1% (reaching 0.468 cm³). 3 / g), and the average pore size also increases accordingly. This marks a complete transformation of the material from a micro-mesoporous hybrid structure to a highly developed mesoporous-dominated structure. This unique structural advantage directly translates into three major performance advantages when applied to CO2 desorption in the potassium lysine system: First, the open mesoporous network provides efficient mass transfer channels for viscous amine-rich solutions, significantly accelerating the reaction of reactants (HCO3-). - / CO3 2- Firstly, the diffusion of the product (CO2) and the catalyst enhances the desorption rate. Secondly, the large pore volume can accommodate more reaction intermediates, effectively alleviating the physical blockage of the pores caused by salt crystallization or polymer deposition, and enhancing the resistance to deactivation. Thirdly, the stable structure formed by the titanium species and the ATP skeleton ensures the long-term stability of the catalyst under high temperature and alkaline regeneration environment.

[0079] Figure 4 Table 4 shows the NH3-TPD curves of the catalyst and the ATP support prepared in Example 2 of this invention. Table 4 also compares the acidity strength data of the catalyst and the ATP support prepared in Example 2 of this invention. Figure 4 As shown in Table 4, Ti modification significantly modulates the acidity characteristics of the catalyst. Untreated attapulgite exhibits a single high-temperature desorption peak at 684.9℃, with a total acid content of 4.67 mmol / g, and its acid sites are mainly distributed in the strong acid region above 600℃. After Ti loading and calcination at 500℃, the desorption peak temperature drops to 573.0℃, and the total acid content decreases to 1.54 mmol / g. The acid intensity distribution shifts significantly, with the main peak falling into the medium-strong acid range of 400–600℃. Peak fitting calculations show that the number of medium-strong acid sites in Ti-ATP is approximately 1.23 mmol / g, accounting for 80% of the total acid content, while strong acid sites (>600℃) account for only about 5%. The shift in acid intensity from 684.9℃ to 573.0℃ makes the acid sites more compatible with the reaction temperature range of CO2 desorption, which is beneficial for the reversible adsorption-desorption process. This is further facilitated by the presence of a large amount of K in the reaction system. +Furthermore, the introduction of Ti may also endow the catalyst with resistance to alkali metal poisoning by forming a Ti-O-ATP interface structure, thereby effectively protecting the active site in the potassium lysine system. Therefore, although the total acid content is reduced, the enrichment of medium-strong acid sites, the optimization of acid strength, and the potential synergistic effect of anti-poisoning jointly promote the improvement of CO2 desorption performance.

[0080] Table 1. Effect of Ti-ATP composite catalysts prepared in Examples 1-5 on CO2 desorption.

[0081] Here, the maximum real-time desorption rate of CO2 refers to the highest peak value of CO2 gas released per unit time during the entire 90-minute heating and regeneration process. The cumulative CO2 desorption volume in 90 minutes refers to the total volume of CO2 gas released from the start of heating to the end of 90 minutes.

[0082] The rate ratio in the first 20 minutes usually refers to the ratio of the average desorption rate of the catalytic group to the average desorption rate of the blank group (without catalyst) in the first 20 minutes.

[0083] Table 2. XRD lattice analysis data of the catalyst

[0084] Table 3. BET structure characterization data of the catalyst

[0085] Table 4 Comparison of acidity strength data of catalysts

[0086] Then, the present invention verified the effect of adding different amounts of Ti-ATP composite catalyst on the desorption process through the following experiments.

[0087] The catalyst was prepared in the same manner as in Example 1. During the analysis, the catalyst dosage was 0 g / L, 2.5 g / L, 5 g / L, 7.5 g / L, and 10 g / L, respectively. The test results are shown in Table 5. As can be seen from Table 5, the experimental effect was best when the catalyst dosage was 7.5 g / L. The main reason is that when the catalyst dosage is too low, there are insufficient active sites, resulting in a significant decrease in reaction rate and conversion rate; the reactants have insufficient residence time and are lost before they can react; at the same time, it is easy to cause uneven fluid distribution, with some reactants passing through directly without catalysis. When the catalyst dosage is too high, it will block the support pores, reduce the specific surface area, and increase the mass transfer resistance; at the same time, it is easy to form a stacked structure, covering acidic sites and active centers, disrupting the Bronsted / Lewis acid balance; and weakening the metal-support interaction, blocking electron transfer and interfacial synergy, ultimately leading to a comprehensive decrease in catalytic activity, selectivity, and stability.

[0088] Table 5. Effect of different catalyst addition amounts on CO2 desorption

[0089] In addition, to verify whether the addition of the catalyst affects the CO2 absorption performance of the absorbent, the following verifications were conducted: Comparative Example 2 Absorption blank experiment: A gas washing bottle containing 40 mL of potassium lysine solution was placed in a 35°C constant temperature water bath. Simulated flue gas (60 mL / min N2 + 10 mL / min CO2) was introduced through one end for absorption observation, while the other end was connected to a drying tube containing anhydrous calcium chloride for drying. The dried gas was then passed through an infrared gas analyzer to analyze the real-time CO2 volume fraction. This absorption experiment was only to demonstrate that the addition of this catalyst would not have a negative impact on the absorption process.

[0090] Unlike the blank absorption experiment, 0.3 g of Ti-ATP was added to a gas washing bottle containing 40 mL of potassium lysine solution for the absorption experiment. The test results are shown in Table 6. As can be seen from Table 6, the addition of Ti-ATP has no adverse effect on the absorption performance of the regenerated solution, and even has a positive effect.

[0091] Table 6. Effect of catalyst addition on CO2 absorption

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A process for the preparation of a titanium modified attapulgite catalyst suitable for use in a potassium lysine system, characterized in that, Includes the following steps: S1: Add attapulgite powder to an aqueous solution of titanium sulfate, sonicate to obtain a Ti-ATP mixture, and subject the Ti-ATP mixture to a water bath heating and stirring treatment to obtain a Ti-ATP mixed suspension. S2: Adjust the pH of the Ti-ATP mixed suspension to 10.0±0.5, then perform a second water bath heating and stirring treatment, and after standing and aging, obtain Ti-ATP coprecipitate; S3: The Ti-ATP coprecipitate is washed, dried, ground and calcined to obtain the titanium-modified attapulgite catalyst suitable for the potassium lysine system, i.e., the Ti-ATP composite catalyst.

2. The method for preparing a titanium-modified attapulgite catalyst suitable for a potassium lysine system according to claim 1, characterized in that, The mass ratio of attapulgite powder to titanium sulfate is 1:(0.5~3).

3. The method for preparing a titanium-modified attapulgite catalyst suitable for a potassium lysine system according to claim 1, characterized in that, The attapulgite powder is 300 mesh, and the ultrasonic time is 20-30 minutes.

4. The method for preparing a titanium-modified attapulgite catalyst suitable for a potassium lysine system according to claim 1, characterized in that, The temperature of the first water bath heating and stirring treatment is 50~60℃, and the time is 8~10h.

5. The method for preparing a titanium-modified attapulgite catalyst suitable for a potassium lysine system according to claim 1, characterized in that, The temperature for the secondary water bath heating and stirring treatment is 50~60℃, and the time is 4~5h; the time for static aging is 10~12h.

6. The method for preparing a titanium-modified attapulgite catalyst suitable for a potassium lysine system according to claim 1, characterized in that, In step S3, the pH value is 7-8.

7. The method for preparing a titanium-modified attapulgite catalyst suitable for a potassium lysine system according to claim 1, characterized in that, In step S3, during the calcination treatment, the heating rate is 2~3℃ / min, the holding temperature is 500℃, and the holding time is 4~6h.

8. A titanium-modified attapulgite catalyst suitable for potassium lysine systems, characterized in that, It is prepared by the method described in any one of claims 1 to 7.

9. The application of the titanium-modified attapulgite catalyst of claim 8 in the lysine potassium system for CO2 desorption.

10. The application of the titanium-modified attapulgite catalyst in the potassium lysine system according to claim 9 for CO2 desorption in the potassium lysine system, characterized in that, The amount of titanium-modified attapulgite catalyst added to the potassium lysine system is 2.5~10 g / L.

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