ZIF-67 derived porous carbon / montmorillonite composite material as well as preparation method and application thereof
By growing ZIF-67 particles on the surface of montmorillonite and calcining carbonization, ZIF-67-derived porous carbon/montmorillonite composite materials were prepared, solving the problems of high preparation cost and high energy consumption of existing photothermal materials, and achieving efficient photothermal conversion and high production efficiency.
Patent Information
- Application Number
- CN202510007296.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-03
- Publication Date
- 2025-04-11
AI Technical Summary
The existing preparation methods of photothermal materials are usually accompanied by large production costs and energy consumption, which are not conducive to large-scale integrated production of fresh water or treatment of sewage.
Using the preparation method of ZIF-67 derived porous carbon/montmorillonite composite material, composite materials with high photothermal conversion ability were prepared by growing ZIF-67 particles in situ on the surface of montmorillonite and calcining and carbonizing at a high temperature of 550-950°C.
It achieves efficient photothermal conversion, with a light absorption exceeding 90% in the full spectrum range, and the preparation process is simple and easy to perform, with high production efficiency, far exceeding the porous carbon derived from ZIF-67.
Smart Images
Figure CN119797384A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of photothermal materials, and in particular to a ZIF-67 derived porous carbon / montmorillonite composite material and a preparation method and application thereof. Background Art
[0002] Photothermal materials are materials that can efficiently convert solar energy into thermal energy and are an important part of the efficient and comprehensive utilization of solar energy. Common photothermal conversion materials include metal nanoparticles, carbon-based materials and metal oxides, and their preparation methods are relatively mature. Metal nanoparticles are often prepared by chemical reduction and photochemical methods. The former uses a reducing agent to reduce metal ions to nanoparticles, and the latter uses a photosensitizer to reduce under light. Carbon-based materials such as carbon nanotubes and graphene are mostly prepared by chemical vapor deposition and solvothermal methods. The former pyrolyzes hydrocarbon gases under the action of high-temperature catalysts, and the latter reacts in high-temperature and high-pressure solvents to generate porous carbon. Metal oxides such as iron oxide and titanium oxide are often prepared by sol-gel and hydrothermal methods. The former is prepared by hydrolysis and polycondensation of metal organic precursors, and the latter reacts in high-temperature and high-pressure aqueous solutions to generate nanoparticles. However, these preparation methods are usually accompanied by large production costs and energy consumption, which is not conducive to large-scale integrated production of fresh water or treatment of sewage. Summary of the invention
[0003] The purpose of the present invention is to address the above-mentioned deficiencies in the prior art and to provide a ZIF-67 derived porous carbon / montmorillonite composite material and a preparation method and application thereof.
[0004] The invention discloses a method for preparing a ZIF-67 derived porous carbon / montmorillonite composite material. The method comprises the following steps: placing an appropriate amount of montmorillonite, cobalt nitrate hexahydrate and 2-methylimidazole in a methanol solution, and in-situ growing ZIF-67 particles on the surface of the montmorillonite; and then calcining and carbonizing the composite material to obtain the ZIF-67 derived porous carbon / montmorillonite composite material.
[0005] Furthermore, the mass ratio of montmorillonite, cobalt nitrate hexahydrate and 2-methylimidazole is 1-3:1:1.
[0006] Furthermore, the calcination carbonization temperature is 550-950°C and the time is 2-4h.
[0007] Furthermore, the heating rate of calcination and carbonization is 10°C / min.
[0008] A ZIF-67 derived porous carbon / montmorillonite composite material prepared by the above preparation method.
[0009] An application of the above-mentioned ZIF-67 derived porous carbon / montmorillonite composite material is used as a photothermal conversion material in seawater desalination and sewage treatment.
[0010] The ZIF-67 derived porous carbon / montmorillonite composite material prepared by the present invention has a simple and easy preparation process and has a high light-heat conversion capacity, and the absorbance is more than 90% in the full spectrum; while ensuring the stability of the absorbance, the production efficiency of the ZIF-67 derived porous carbon / montmorillonite composite material far exceeds that of the ZIF-67 derived porous carbon. After calcination, the organic ligand of ZIF-67 decomposes, leaving the nitrogen-doped porous carbon material. This process will cause the quality loss and agglomeration of the porous carbon, thereby affecting the light absorption and production efficiency. After the same mass of ZIF-67 is loaded on montmorillonite and carbonized, the structural regulation in the carbonization process is strengthened, the dispersion of the granular porous carbon is strengthened, and large-scale efficient preparation is achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 The light absorption effects of ZIF-67, ZIF-67 derived porous carbon prepared in Comparative Example 1, and ZIF-67 derived porous carbon / montmorillonite prepared in Example 2;
[0012] Figure 2 The microscopic morphology of ZIF-67 and ZIF-67 derived porous carbon / montmorillonite prepared in Example 2;
[0013] Figure 3 The ZIF-67 derived porous carbon prepared in Comparative Example 1 and the ZIF-67 derived porous carbon / montmorillonite N prepared in Example 2 2 Adsorption-desorption isotherms;
[0014] Figure 4 The pore size distribution of the ZIF-67 derived porous carbon prepared in Comparative Example 1 and the ZIF-67 derived porous carbon / montmorillonite prepared in Example 2;
[0015] Figure 5 The desalination effect of the prepared ZIF-67 derived porous carbon / montmorillonite hydrogel;
[0016] Figure 6 This is a photo of the prepared ZIF-67 derived porous carbon hydrogel;
[0017] Figure 7 Photo of the prepared ZIF-67 derived porous carbon / montmorillonite hydrogel. DETAILED DESCRIPTION
[0018] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.
[0019] Embodiment 1:
[0020] Preparation of ZIF-67-derived porous carbon / montmorillonite composites
[0021] Dissolve 1g of cobalt nitrate hexahydrate in 10ml of methanol, 1g of 2-methylimidazole in another 40ml of methanol, and 2g of montmorillonite in 50ml of methanol. After dissolving them separately, dissolve the cobalt nitrate hexahydrate-methanol solution and add it dropwise to the montmorillonite-methanol solution. After stirring at room temperature for 1h, slowly pour 2-methylimidazole into the above mixed solution in a straight line. After stirring at room temperature for 1h, let it stand for 24h to obtain a beautiful purple precipitate, which is montmorillonite / ZIF-67. Place montmorillonite / ZIF-67 in a tubular furnace with an argon atmosphere at a heating rate of 10℃ / min and keep it at 550℃ for 3h to obtain a ZIF-67-derived porous carbon / montmorillonite composite material.
[0022] Example 2
[0023] Preparation of ZIF-67-derived porous carbon / montmorillonite composites
[0024] Dissolve 1g of cobalt nitrate hexahydrate in 10ml of methanol, 1g of 2-methylimidazole in another 40ml of methanol, and 2g of montmorillonite in 50ml of methanol. After dissolving them separately, dissolve the cobalt nitrate hexahydrate-methanol solution and add it dropwise to the montmorillonite-methanol solution. After stirring at room temperature for 1h, slowly pour 2-methylimidazole into the above mixed solution in a straight line. After stirring at room temperature for 1h, let it stand for 24h to obtain a beautiful purple precipitate, which is montmorillonite / ZIF-67. Place montmorillonite / ZIF-67 in a tubular furnace with an argon atmosphere at a heating rate of 10℃ / min and keep it at 750℃ for 3h to obtain a ZIF-67-derived porous carbon / montmorillonite composite material.
[0025] Embodiment 3:
[0026] Preparation of ZIF-67-derived porous carbon / montmorillonite composites
[0027] Dissolve 1g of cobalt nitrate hexahydrate in 10ml of methanol, 1g of 2-methylimidazole in another 40ml of methanol, and 2g of montmorillonite in 50ml of methanol. After dissolving them separately, dissolve the cobalt nitrate hexahydrate-methanol solution and add it dropwise to the montmorillonite-methanol solution. After stirring at room temperature for 1h, slowly pour 2-methylimidazole into the above mixed solution in a straight line. After stirring at room temperature for 1h, let it stand for 24h to obtain a beautiful purple precipitate, which is montmorillonite / ZIF-67. Place montmorillonite / ZIF-67 in a tubular furnace with an argon atmosphere at a heating rate of 10℃ / min and keep it at 950℃ for 3h to obtain a ZIF-67-derived porous carbon / montmorillonite composite material.
[0028] Comparative Example 1:
[0029] ZIF-67 derived porous carbon
[0030] Dissolve 1g of cobalt nitrate hexahydrate in 10ml of methanol and 1g of 2-methylimidazole in another 40ml of methanol. After dissolving separately, slowly pour 2-methylimidazole into the cobalt nitrate hexahydrate-methanol solution in a straight line, stir at room temperature for 1h and let stand for 24h to obtain a beautiful purple precipitate, which is ZIF-67. Place ZIF-67 in a tube furnace with an argon atmosphere and heat at 750℃ for 3h at a rate of 10℃ / min to obtain ZIF-67-derived porous carbon.
[0031] Figure 1 The light absorption effect of ZIF-67, ZIF-67 derived porous carbon prepared in comparative example 1, and ZIF-67 derived porous carbon / montmorillonite prepared in example 2. After ZIF-67 is calcined into porous carbon, the light absorption capacity is significantly improved. According to the illustration, after ZIF-67 is loaded on MMT and calcined, the light absorption rate is also improved. It is due to the microscopic regulation of porous carbon by MMT, which changes the absorption and scattering of light and improves the light absorption rate. The absorbance is more than 90% in the full spectrum.
[0032] Figure 2 The microscopic morphology of ZIF-67 and ZIF-67-derived porous carbon / montmorillonite prepared in Example 2; ZIF-67 presents an agglomerated cubic morphology, and presents a separated porous spherical carbon morphology after composite calcination with montmorillonite.
[0033] Figure 3 The ZIF-67 derived porous carbon prepared in Comparative Example 1 and the ZIF-67 derived porous carbon / montmorillonite N prepared in Example 2 2 Adsorption-desorption isotherm curve; the specific surface area of ZIF-67 derived porous carbon / montmorillonite is higher than that of ZIF-67 derived porous carbon.
[0034] Figure 4 The pore size distributions of the ZIF-67 derived porous carbon prepared in Comparative Example 1 and the ZIF-67 derived porous carbon / montmorillonite prepared in Example 2; the ZIF-67 derived porous carbon / montmorillonite has a richer pore structure than the ZIF-67 derived porous carbon.
[0035] Application Examples
[0036] Preparation of ZIF-67-derived porous carbon / montmorillonite hydrogel
[0037] 0.80g chitosan and 2.40g polyvinyl alcohol were dispersed in a beaker containing 40ml pure water, and heated at 90°C for 3h to melt to obtain a mixed solution. After the mixed solution was cooled to room temperature, 1wt% acetic acid solution was added, and 4wt% ZIF-67 derived porous carbon / montmorillonite composite material (prepared in Example 2) was dispersed by ultrasonic stirring after rapid stirring and crosslinking for 30min. Finally, the solution was poured into an acrylic mold with a diameter of 3cm and a height of 2cm, and low-temperature solidification at -25°C for 6h was performed, and then melted at room temperature, and repeated three times.
[0038] Preparation of ZIF-67-derived porous carbon hydrogel
[0039] The ZIF-67-derived porous carbon / montmorillonite composite material (prepared in Example 2) was replaced by the ZIF-67-derived porous carbon prepared in the comparative example, and the rest was the same as in Example 4 to prepare a ZIF-67-derived porous carbon hydrogel, whose strength was lower than that of the ZIF-67-derived porous carbon / montmorillonite hydrogel prepared in Example 4.
[0040] Desalinated seawater ion concentration test: The hydrogel was placed between a transparent glass cover and a transparent glass plate, and 1 mL of distilled water desalinated in step (5) and 1 mL of undesalinated seawater were collected for inductively coupled plasma atomic emission spectrometry test. The ions measured were Na + , K + , Ca 2+ Mg 2+ .
[0041] Figure 5 The desalination effect of the prepared ZIF-67 derived porous carbon / montmorillonite hydrogel; ZIF-67 derived porous carbon / montmorillonite hydrogel was used to desalinate seawater by interfacial evaporation. By collecting the distilled water during the desalination process, it was proved that the hydrogel can effectively remove metal ions in seawater (Yellow Sea seawater), with a metal ion interception rate of up to 98% and a desalination capacity of over 98%.
[0042] Water evaporation capacity test: The hydrogel was placed in a beaker of fresh water, a xenon lamp was used as the solar light source, an optical power meter was used to measure the solar energy functional density, and an electronic balance was used to monitor the mass change of water during the solar energy driven evaporation process. The ambient temperature and humidity were 26°C and 50%, respectively. Under continuous sunlight, the water evaporation rate can reach 2.2 kg m -2 h -1 . Its evaporation enthalpy is 1360 J / g.
[0043] Figure 6 This is a photo of the prepared ZIF-67 derived porous carbon hydrogel. As can be seen from the figure, the mechanical strength is low and the surface of the hydrogel is not smooth enough after demolding and surface damage occurs.
[0044] Figure 7 This is a photo of the prepared ZIF-67 derived porous carbon / montmorillonite hydrogel; due to the introduction of ZIF-67 derived porous carbon / montmorillonite composite materials, the cross-linking sites of the polymer long chains are enriched, and the ZIF-67 derived porous carbon / montmorillonite composite materials have strong mechanical stability. The synergistic effect of the two improves the cross-linking density and mechanical strength. After demolding, the hydrogel surface is smooth and the structure is complete.
[0045] For matters not mentioned above, the prior art applies.
[0046] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art to which the present invention belongs may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but they will not deviate from the direction of the present invention or exceed the scope defined by the attached claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing a ZIF-67 derived porous carbon / montmorillonite composite material, characterized in that: An appropriate amount of montmorillonite, cobalt nitrate hexahydrate and 2-methylimidazole are placed in a methanol solution to in-situ grow ZIF-67 particles on the surface of montmorillonite; the composite material is then calcined and carbonized to obtain a ZIF-67-derived porous carbon / montmorillonite composite material.
2. The preparation method according to claim 1, characterized in that The mass ratio of montmorillonite, cobalt nitrate hexahydrate and 2-methylimidazole is 1-3:1:
1.
3. The preparation method according to claim 1, characterized in that: The calcination carbonization temperature is 550-950°C and the time is 2-4h.
4. The preparation method according to claim 1, characterized in that: The heating rate of calcination and carbonization was 10°C / min.
5. The preparation method according to claim 1, characterized in that: In step S2, the mass of ZIF-67 derived porous carbon / montmorillonite is 1-4 wt% of the total mass of the solution.
6. The preparation method according to claim 5, characterized in that: The mass ratio of ZIF-67 derived porous carbon / montmorillonite, polyvinyl alcohol and chitosan is 1-3:1-2:3-4.
7. A ZIF-67 derived porous carbon / montmorillonite composite material prepared by the preparation method according to any one of claims 1 to 6.
8. An application of the ZIF-67 derived porous carbon / montmorillonite composite material as claimed in claim 7, characterized in that: It is used as a photothermal conversion material in seawater desalination and sewage treatment.