Efficient desulfurization titanium-based hydrotalcite-like material and preparation method thereof
By introducing trivalent cerium ions into titanium-based LDH materials, the interlayer spacing and active surface area are increased, solving the problems of insufficient specific surface area and poor adsorption selectivity of traditional titanium-based LDH materials, and achieving efficient adsorption of organic sulfides.
Patent Information
- Application Number
- CN202511235475.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-01
- Publication Date
- 2025-12-16
AI Technical Summary
Traditional titanium-based LDH materials suffer from low specific surface area, poor matching between interlayer channel size and target molecules, and insufficient surface active groups, which limits adsorption efficiency.
By partially replacing trivalent aluminum ions with trivalent cerium in the laminate structure, the interlayer spacing and interlayer channel size are increased, promoting lamellar dispersion, exposing more active surfaces, and the density of adsorption sites and the number of active groups are improved through cerium doping.
It significantly improves the specific surface area and adsorption selectivity of titanium-based hydrotalcite materials, enhances the adsorption effect on organic sulfides, has large interlayer channels that can adsorb on both the inner and outer surfaces, improves the density and activity of adsorption sites, and enhances the adsorption effect.
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Figure CN121134825A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of hydrotalcite materials, and particularly relates to a high-efficiency desulfurization titanium-based hydrotalcite material and a preparation method thereof. BACKGROUND
[0002] Hydrotalcite-like compounds (LDH) are a class of layered double hydroxide composite metal oxides composed of two or more metal hydroxide layers. The core structure is formed by divalent and trivalent metal cations bridged by hydroxyl ions to form positively charged layers, and the interlayer is maintained by exchangeable anions. Due to its unique two-dimensional layered structure, adjustable interlayer chemical environment and excellent ion exchange capacity, this material has shown wide application potential in catalysis, adsorption, medicine and environmental governance.
[0003] LDH has many ideal chemical and physical properties, such as acidity and alkalinity, thermal stability, ion exchange capacity, memory effect, etc. First, the acidity and alkalinity of LDH is one of its basic properties, and its alkalinity is basically similar to that of the hydroxide corresponding to the divalent metal cation, and its acidity is affected by the divalent and trivalent metal cations and the interlayer anions; when the interlayer anion has strong conjugate acidity, the LDH has strong acidity and is overall acidic; when the interlayer anion has weak conjugate acidity, the LDH is overall alkaline, and the derivative LDO obtained by calcination usually has strong alkalinity. Second, the morphology, surface area, particle size and porosity of LDH are important parameters for describing its structure; these characteristics are affected by the preparation conditions and methods, thereby determining the shape, morphology and specific surface area of LDH. After calcination at a certain temperature, the layered structure of LDH changes into an oxide or a mixture of oxides, thereby changing its morphology, and the porosity of the obtained LDH changes significantly in the range from microporous to mesoporous, and its particle size also varies due to the differences in composition and crystallinity. Third, the thermal decomposition process of hydrotalcite mainly includes removal of interlayer water, dehydroxylation and generation of new phases, which together constitute the complete process of thermal decomposition of hydrotalcite; the exact temperature range of each thermal decomposition step of LDH depends on several factors, such as the type of LDH, heating rate and inert atmosphere, etc.
[0004] The inherent two-dimensional structure characteristics of LDH, such as large specific surface area, exchangeable anions and flexible interlayer space, make it a very promising pollutant adsorbent material. The exchangeable interlayer anions and high specific surface area of LDH make it a high-efficiency adsorbent, especially suitable for the removal of organic sulfides (such as ethyl mercaptan).
[0005] However, the traditional titanium-based LDH material has problems such as low specific surface area, poor matching of interlayer channel size with target molecules, and insufficient surface active groups, which limits the adsorption efficiency. SUMMARY
[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a highly efficient desulfurized titanium-based hydrotalcite material and its preparation method.
[0007] A method for preparing a highly efficient desulfurized titanium-based hydrotalcite material includes the following steps:
[0008] S1. Add zinc nitrate hexahydrate and urea to water and stir for 10-20 min. Add titanium tetrachloride dropwise and continue stirring for 20-40 min. Ag at 120-140℃ for 40-50 h. Filter, wash, vacuum dry, and grind to obtain the precursor.
[0009] S2. Dissolve aluminum chloride hexahydrate and cerium chloride in water, add the precursor and stir for 20-40 min, react at 160-180℃ for 15-20 h, cool to room temperature, wash until neutral, vacuum dry, cool to room temperature, heat to 300-400℃, keep at that temperature for 5-10 h, and then cool to room temperature.
[0010] Preferably, in S1, the molar ratio of zinc nitrate hexahydrate, titanium tetrachloride, and urea is 2-4:1:20-30.
[0011] Preferably, in S1, the molar volume ratio of urea to water (mol:mL) is 0.04-0.06:100.
[0012] Preferably, in S1, the vacuum drying temperature is 60-70℃ and the vacuum drying time is 10-15h.
[0013] Preferably, in S2, the mass ratio of aluminum chloride hexahydrate, cerium chloride, and the precursor is 1:0.1-0.2:25-35.
[0014] Preferably, in S2, the mass-to-volume ratio (g:mL) of aluminum chloride hexahydrate to deionized water is 0.1:350-450.
[0015] Preferably, in S2, the vacuum drying temperature is 65-75℃ and the vacuum drying time is 20-30h.
[0016] Preferably, in S2, during the process of heating to 300-400℃, the heating rate is 1-5℃ / min.
[0017] A highly efficient desulfurized titanium-based hydrotalcite material is prepared using the aforementioned method for preparing highly efficient desulfurized titanium-based hydrotalcite materials.
[0018] The aforementioned high-efficiency desulfurization titanium-based hydrotalcite material is used for adsorption and catalytic desulfurization.
[0019] Beneficial effects:
[0020] This invention employs trivalent cerium to partially replace trivalent aluminum ions in the laminate structure, resulting in a decrease in laminate charge density, weakened interlayer electrostatic repulsion, and increased interlayer spacing. This significantly improves the matching degree between the interlayer channel size and ethanethiol molecules, thereby increasing the number of adsorption sites on the inner surface. Simultaneously, cerium doping inhibits laminate stacking, promotes lamellar dispersion, and exposes more active surfaces. This not only maintains adsorption activity over a long period but also further enhances the adsorption site density, thus strengthening the adsorption effect.
[0021] This invention effectively solves the problems of insufficient specific surface area and poor adsorption selectivity. It has high sulfur penetration capacity and excellent adsorption performance, significantly enhancing the adsorption effect of organic sulfur compounds. The product has large interlayer channels, which can be adsorbed on both the outer and inner surfaces. This not only increases the contact area with sulfur-containing compounds, which is beneficial to the adsorption of sulfur-containing compounds, but also allows the active groups to form hydrogen bonds with sulfur-containing compounds, which is also beneficial to the adsorption of sulfur-containing compounds.
[0022] The preparation method of this invention is simple, and it has excellent adsorption effect on sulfur-containing compounds, making it suitable for large-scale application. Attached Figure Description
[0023] Figure 1 The diagram shows a comparison of the specific surface area and the corresponding total pore volume of single-point desorption of the titanium-based hydrotalcite materials obtained in Example 5 and Comparative Examples 1-3.
[0024] Figure 2 This is a schematic diagram of a desulfurization unit.
[0025] Figure 3 The graph shows a comparison of the adsorption breakthrough time and sulfur capacity of ethanethiol by the titanium-based hydrotalcite materials obtained in Example 5 and Comparative Examples 1-3. Detailed Implementation
[0026] The present invention will be further explained below with reference to specific embodiments.
[0027] Example 1
[0028] A high-efficiency desulfurization titanium-based hydrotalcite material includes the following steps:
[0029] S1. Add 0.002 mol zinc nitrate hexahydrate and 0.02 mol urea to 50 mL deionized water, stir at 1000 r / min for 10 min, add 0.001 mol titanium tetrachloride dropwise, continue stirring for 20 min, pour the solution into a reaction vessel, age at 120℃ for 40 h, filter, wash with anhydrous ethanol, vacuum dry at 60℃ for 10 h, and grind to obtain the precursor;
[0030] S2. Dissolve 0.1g aluminum chloride hexahydrate and 0.01g cerium chloride in 350mL of deionized water, add 2.5g of precursor and stir for 20min. Transfer to a reaction vessel and react at 160℃ for 15h. Cool to room temperature, and wash the filtered product with 40% ethanol solution until neutral. Dry under vacuum at 65℃ for 20h, cool to room temperature, place in a muffle furnace, heat to 300℃ at a rate of 1℃ / min, hold for 5h, and then cool to room temperature.
[0031] Example 2
[0032] A high-efficiency desulfurization titanium-based hydrotalcite material includes the following steps:
[0033] S1. Add 0.004 mol zinc nitrate hexahydrate and 0.03 mol urea to 50 mL of deionized water, stir at 1500 r / min for 20 min, add 0.001 mol titanium tetrachloride dropwise, continue stirring for 40 min, pour the solution into a reaction vessel, age at 140℃ for 50 h, filter, wash with anhydrous ethanol, vacuum dry at 70℃ for 15 h, and grind to obtain the precursor;
[0034] S2. Dissolve 0.1g aluminum chloride hexahydrate and 0.02g cerium chloride in 450mL of deionized water, add 3.5g of precursor and stir for 40min. Transfer to a reaction vessel and react at 180℃ for 20h. Cool to room temperature, and wash the filtered product with 60% ethanol solution until neutral. Dry under vacuum at 75℃ for 30h, cool to room temperature, place in a muffle furnace, heat to 400℃ at a rate of 5℃ / min, hold for 10h, and then cool to room temperature.
[0035] Example 3
[0036] A high-efficiency desulfurization titanium-based hydrotalcite material includes the following steps:
[0037] S1. Add 0.0025 mol zinc nitrate hexahydrate and 0.028 mol urea to 50 mL deionized water, stir at 1100 r / min for 18 min, add 0.001 mol titanium tetrachloride dropwise, continue stirring for 25 min, pour the solution into a reaction vessel, age at 135℃ for 42 h, filter, wash with anhydrous ethanol, vacuum dry at 68℃ for 11 h, and grind to obtain the precursor;
[0038] S2. Dissolve 0.1g aluminum chloride hexahydrate and 0.018g cerium chloride in 380mL of deionized water, add 3.2g of precursor and stir for 25min, transfer to a reaction vessel, react at 175℃ for 17h, cool to room temperature, wash the filtered product with 55% ethanol solution to neutralize, vacuum dry at 68℃ for 28h, cool to room temperature, place in a muffle furnace, heat to 370℃ at a rate of 2℃ / min, hold at 370℃ for 7h, and then cool to room temperature.
[0039] Example 4
[0040] A high-efficiency desulfurization titanium-based hydrotalcite material includes the following steps:
[0041] S1. Add 0.0035 mol zinc nitrate hexahydrate and 0.022 mol urea to 50 mL deionized water, stir at 1300 r / min for 12 min, add 0.001 mol titanium tetrachloride dropwise, continue stirring for 35 min, pour the solution into a reaction vessel, age at 125℃ for 48 h, filter, wash with anhydrous ethanol, vacuum dry at 62℃ for 13 h, and grind to obtain the precursor;
[0042] S2. Dissolve 0.1g aluminum chloride hexahydrate and 0.012g cerium chloride in 420mL of deionized water, add 2.8g of precursor and stir for 35min. Transfer to a reaction vessel and react at 165℃ for 19h. Cool to room temperature, wash the filtered product with 45% ethanol solution until neutral, dry under vacuum at 72℃ for 22h, cool to room temperature, place in a muffle furnace, heat to 330℃ at a rate of 4℃ / min, hold at that temperature for 9h, and then cool to room temperature.
[0043] Example 5
[0044] A high-efficiency desulfurization titanium-based hydrotalcite material includes the following steps:
[0045] S1. Add 0.003 mol zinc nitrate hexahydrate and 0.025 mol urea to 50 mL deionized water, stir at 1200 r / min for 15 min, add 0.001 mol titanium tetrachloride dropwise, continue stirring for 30 min, pour the solution into a reaction vessel, age at 130℃ for 45 h, filter, wash with anhydrous ethanol, vacuum dry at 65℃ for 12 h, and grind to obtain the precursor;
[0046] S2. Dissolve 0.1g aluminum chloride hexahydrate and 0.015g cerium chloride in 400mL of deionized water, add 3g of precursor and stir for 30min, transfer to a reaction vessel, react at 170℃ for 18h, cool to room temperature, wash the filtered product with 50% ethanol solution to neutralize it, vacuum dry at 70℃ for 25h, cool to room temperature, place in a muffle furnace, heat to 350℃ at a rate of 3℃ / min, hold at that temperature for 8h, and then cool to room temperature.
[0047] Comparative Example 1
[0048] A high-efficiency desulfurization titanium-based hydrotalcite material includes the following steps:
[0049] S1. Add 0.003 mol zinc nitrate hexahydrate and 0.025 mol urea to 50 mL deionized water, stir at 1200 r / min for 15 min, add 0.001 mol titanium tetrachloride dropwise, continue stirring for 30 min, pour the solution into a reaction vessel, age at 130℃ for 45 h, filter, wash with anhydrous ethanol, vacuum dry at 65℃ for 12 h, and grind to obtain the precursor;
[0050] S2. Dissolve 0.1g of aluminum chloride hexahydrate in 400mL of deionized water, add 3g of precursor and stir for 30min, transfer to a reaction vessel, react at 170℃ for 18h, cool to room temperature, wash the filtered product with 50% ethanol solution to neutralize it, vacuum dry at 70℃ for 25h, cool to room temperature, place in a muffle furnace, heat to 350℃ at a rate of 3℃ / min, hold at that temperature for 8h, and then cool to room temperature.
[0051] Comparative Example 2
[0052] A high-efficiency desulfurization titanium-based hydrotalcite material includes the following steps:
[0053] S1. Add 0.003 mol zinc nitrate hexahydrate and 0.025 mol urea to 50 mL deionized water, stir at 1200 r / min for 15 min, add 0.001 mol titanium tetrachloride dropwise, continue stirring for 30 min, pour the solution into a reaction vessel, age at 130℃ for 45 h, filter, wash with anhydrous ethanol, vacuum dry at 65℃ for 12 h, and grind to obtain the precursor;
[0054] S2. Dissolve 0.1g ferric chloride hexahydrate and 0.015g cerium chloride in 400mL of deionized water, add 3g of precursor and stir for 30min, transfer to a reaction vessel, react at 170℃ for 18h, cool to room temperature, wash the filtered product with 50% ethanol solution to neutralize it, vacuum dry at 70℃ for 25h, cool to room temperature, place in a muffle furnace, heat to 350℃ at a rate of 3℃ / min, hold at that temperature for 8h, and then cool to room temperature.
[0055] Comparative Example 3
[0056] A high-efficiency desulfurization titanium-based hydrotalcite material includes the following steps:
[0057] S1. Add 0.003 mol zinc nitrate hexahydrate and 0.025 mol urea to 50 mL deionized water, stir at 1200 r / min for 15 min, add 0.001 mol titanium tetrachloride dropwise, continue stirring for 30 min, pour the solution into a reaction vessel, age at 130℃ for 45 h, filter, wash with anhydrous ethanol, vacuum dry at 65℃ for 12 h, and grind to obtain the precursor;
[0058] S2. Dissolve 0.1g of ferric chloride hexahydrate in 400mL of deionized water, add 3g of precursor and stir for 30min, transfer to a reaction vessel, react at 170℃ for 18h, cool to room temperature, wash the filtered product with 50% ethanol solution to neutralize it, vacuum dry at 70℃ for 25h, cool to room temperature, place in a muffle furnace, heat to 300℃ at a rate of 5℃ / min, hold at that temperature for 5h, and then cool to room temperature.
[0059] The titanium-based hydrotalcite materials obtained in Example 5 and Comparative Examples 1-3 were subjected to adsorption-desorption isotherm measurements using an ASAP 2460 physical adsorption instrument (liquid nitrogen temperature 77K) to characterize BET. Before the test, the samples were degassed at 473K for 6 hours under vacuum degassing pretreatment.
[0060] According to the IUPAC definition, the nitrogen adsorption-desorption isotherms of each group of titanium-based hydrotalcite materials exhibit type IV curves. The titanium-based hydrotalcite materials obtained in Example 5 and Comparative Example 2 have H2-type hysteresis loops, indicating that a relatively regular mesoporous structure has been formed in the two groups of titanium-based hydrotalcite materials, while the titanium-based hydrotalcite materials obtained in Comparative Example 1 and Comparative Example 3 have H3-type hysteresis loops, and relatively uniform slit-like mesopores exist in the two groups of titanium-based hydrotalcite materials.
[0061] The specific surface area and corresponding total pore volume of single-point desorption of each group of titanium-based hydrotalcite materials are as follows: Figure 1As shown, the titanium-based hydrotalcite material obtained in Example 5 has the largest specific surface area and corresponding total pore volume for single-point desorption, which is superior to Comparative Examples 1-3 (P<0.05), and can provide abundant adsorption sites for the adsorption of sulfur-containing compounds.
[0062] Using ethanethiol as the sulfur-containing compound, dynamic adsorption-photocatalysis experiments were conducted on the titanium-based hydrotalcite materials obtained in Example 5 and Comparative Examples 1-3.
[0063] Under dark chamber and nitrogen protection conditions, a 500ppm CH3CH2SH / CH4 mixed gas was used to simulate natural gas. Adsorption experiments were conducted at room temperature using a fixed-bed reactor to test the desulfurization performance of the samples. The desulfurization device was as follows: Figure 2 As shown.
[0064] The quartz tube adsorption column used in the experiment had an inner diameter of 4 mm and a length of 240 mm, with 0.10 g of sample loaded for each group. Before the adsorption test, each group of samples was pretreated by purging with nitrogen at 120℃ for 1 h. After pretreatment, the program was set as follows: FPD detector, column oven 140℃, vaporization chamber 180℃, detector 280℃, and a mixed gas containing 500 ppm CH3CH2SH was introduced at a flow rate of 15 mL / min. When the detector detected a peak of ethanethiol or diethyl disulfide in the tail gas, it was considered that the catalyst had been penetrated, and the sulfur capacity at this time was the breakthrough adsorption sulfur capacity.
[0065] like Figure 3 As shown, the titanium-based hydrotalcite material obtained in Example 5 had the longest adsorption and penetration time for ethanethiol, and the largest sulfur capacity for ethanethiol adsorption, which was superior to Comparative Examples 1-3 (P<0.05).
[0066] The reason for the above results is that the present invention uses trivalent cerium to partially replace trivalent aluminum ions in the lamellar structure, resulting in a decrease in the charge density of the lamellar structure, a weakening of the electrostatic repulsion between layers, an increase in the interlayer spacing, and a significant improvement in the matching degree between the interlayer channel size and ethanethiol molecules, thereby increasing the number of adsorption sites on the inner surface. Simultaneously, cerium doping can inhibit lamellar stacking, promote lamellar dispersion, and expose more active surfaces, not only maintaining adsorption activity for a long time but also further increasing the density of adsorption sites and enhancing the adsorption effect. The present invention effectively solves the problems of insufficient specific surface area and poor adsorption selectivity, exhibits high sulfur penetration capacity and excellent adsorption performance, and significantly enhances the adsorption effect of organic sulfides. The large interlayer channels of the product allow adsorption on both the outer and inner surfaces, increasing the contact area with sulfur-containing compounds, which is beneficial for their adsorption. Furthermore, the active groups can form hydrogen bonds with sulfur-containing compounds, which is also beneficial for their adsorption.
[0067] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing a highly efficient desulfurized titanium-based hydrotalcite material, characterized in that, Includes the following steps: S1. Add zinc nitrate hexahydrate and urea to water and stir for 10-20 min. Add titanium tetrachloride dropwise and continue stirring for 20-40 min. Ag at 120-140℃ for 40-50 h. Filter, wash, vacuum dry, and grind to obtain the precursor. S2. Dissolve aluminum chloride hexahydrate and cerium chloride in water, add the precursor and stir for 20-40 min, react at 160-180℃ for 15-20 h, cool to room temperature, wash until neutral, vacuum dry, cool to room temperature, heat to 300-400℃, keep at that temperature for 5-10 h, and then cool to room temperature.
2. The preparation method of the high-efficiency desulfurization titanium-based hydrotalcite material according to claim 1, characterized in that, In S1, the molar ratio of zinc nitrate hexahydrate, titanium tetrachloride, and urea is 2-4:1:20-30.
3. The preparation method of the high-efficiency desulfurization titanium-based hydrotalcite material according to claim 1, characterized in that, In S1, the molar volume ratio of urea to water (mol:mL) is 0.04-0.06:
100.
4. The preparation method of the high-efficiency desulfurization titanium-based hydrotalcite material according to claim 1, characterized in that, In S1, the vacuum drying temperature is 60-70℃ and the vacuum drying time is 10-15h.
5. The preparation method of the high-efficiency desulfurization titanium-based hydrotalcite material according to claim 1, characterized in that, In S2, the mass ratio of aluminum chloride hexahydrate, cerium chloride, and the precursor is 1:0.1-0.2:25-35.
6. The preparation method of the high-efficiency desulfurization titanium-based hydrotalcite material according to claim 1, characterized in that, In S2, the mass-to-volume ratio of aluminum chloride hexahydrate to deionized water (g:mL) is 0.1:350-450.
7. The preparation method of the high-efficiency desulfurization titanium-based hydrotalcite material according to claim 1, characterized in that, In S2, the vacuum drying temperature is 65-75℃ and the vacuum drying time is 20-30h.
8. The preparation method of the high-efficiency desulfurization titanium-based hydrotalcite material according to claim 1, characterized in that, In S2, the heating rate is 1-5℃ / min during the process of heating to 300-400℃.
9. A high-efficiency desulfurization titanium-based hydrotalcite material, characterized in that, The material was prepared using the method described in any one of claims 1-8 for the preparation of highly efficient desulfurized titanium-based hydrotalcite.
10. The high-efficiency desulfurization titanium-based hydrotalcite material as described in claim 9 is used for adsorption and catalytic desulfurization.