Silicon dioxide microcapsule with carbon dioxide adsorption capacity and preparation method thereof

Abstract

The invention discloses a silicon dioxide microcapsule with carbon dioxide adsorption capacity and a preparation method thereof, and belongs to the field of carbon dioxide adsorption materials. According to the preparation method, an interfacial polymerization method is adopted, organic amine is dispersed in an oily solvent, emulsification of an oil phase and a water phase is achieved through a surfactant, then a wall layer material is added to wrap the organic amine, the microcapsule which is smooth in surface and obvious in sphericity is successfully prepared, and the particle size of the microcapsule is 200-350 microns. The adsorption capacity of the microcapsule to CO2 can reach 3.46 mmol / g to the maximum, and the microcapsule can still keep good performance at the low temperature of-30 DEG C. In addition, the thermal decomposition temperature of the microcapsule is up to 250 DEG C, the microcapsule can be recycled for more than 60 times, and the microcapsule shows excellent thermal stability and reusability. Silicon dioxide is adopted as a shell of the microcapsule, the microcapsule has the advantages of being stable in chemical property, good in biocompatibility, resistant to high temperature, insoluble in water and the like, CO2 molecules can pass through the pore structure of the microcapsule and react with an internal adsorbent, and therefore efficient adsorption and desorption functions are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide adsorption materials, and particularly relates to a silica microcapsule with carbon dioxide adsorption ability and a preparation method thereof. Background Art

[0002] The problem of global climate change has become a severe challenge faced by the world today. The main reason is the excessive emission of greenhouse gases. Among various greenhouse gases, the emission of carbon dioxide remains high, having a profound impact on the earth's ecological environment and climate system. Although traditional emission reduction measures have achieved certain results, there are still many limitations in the face of the urgency of addressing climate change. Therefore, there is an urgent need for an efficient and sustainable solution to achieve the rational utilization of carbon resources and the coordinated development of the environment. The proposal of carbon capture, utilization, and storage (CCUS) technology provides a direction for the rational utilization of carbon resources.

[0003] In the field of carbon capture, utilization, and storage (CCUS), the amine / ammonia method for carbon dioxide adsorption is widely used, especially the organic amine absorbent absorption method, which has currently become one of the most mature and widely adopted methods in industry. However, this method has problems such as equipment corrosion and easy volatilization of the adsorbent. Therefore, how to effectively reduce volatilization and reduce equipment corrosion to achieve a high CO 2 capture effect is an urgent problem to be solved. Patent CN 113426249A discloses a mixed organic amine CO 2 absorbent. When the composition of the absorbent is monoethanolamine and diethylenetriamine and their ratio is 8:2, it has the maximum CO 2 absorption amount, and the absorption amount can reach 0.01534 mol / L.

[0004] Microcapsule technology is a process of using a core-shell structure to encapsulate solid particles, liquid droplets, or gases as core materials and form a continuous and thin outer shell on their outside. Microcapsules can be used to achieve applications such as drug controlled release, flavor release, and food preservation by encapsulating functional substances. Patent CN 108057402A discloses a method for preparing microcapsules containing pure polyamine. The preparation of microcapsules is achieved through a microdroplet device, but its preparation method requires special equipment and complex processes, increasing the production cost.

[0005] Combining the above technologies, microcapsules encapsulating organic amines are used to prepare CO 2Adsorbent materials have significant application potential. By encapsulating organic amines in microcapsules, not only can the volatilization of amines be reduced and their loss during use be reduced, but also the direct contact between amines and the external environment can be effectively avoided, thereby reducing corrosion to equipment and potential harm to the health of operators. In addition, this encapsulation method can also reduce the diffusion of amines in the air, reduce pollution to the surrounding environment, and improve the safety and environmental protection of the entire carbon capture system. It can be seen that microcapsule technology provides an effective solution for the improvement of organic amine adsorbents, which is expected to reduce regeneration energy consumption while improving CO 2 Capture efficiency, providing strong support for the further development of CCUS technology. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a silicon dioxide microcapsule having excellent thermal stability and reusability and strong carbon dioxide adsorption capacity and a preparation method thereof.

[0007] The silicon dioxide microcapsule with carbon dioxide adsorption capacity provided by the invention is a microcapsule with silicon dioxide as capsule wall and organic amine as capsule core, which is prepared by using any one of tetraethyl silicate and phenyltriethoxysilane as wall material raw material through interfacial polymerization method.

[0008] Furthermore, the organic amine is selected from any one or more of ethanolamine, diglycolamine, 2-amino-2-methyl-1-propanol, piperazine, diisopropanolamine, triethylenetetramine, tetraethylenepentamine and 1,3-propylenediamine.

[0009] The method for preparing silicon dioxide microcapsules with carbon dioxide adsorption capacity provided by the present invention comprises the following steps:

[0010] Step 1: Mix kerosene, organic amine and surfactant, and fully disperse them to form an emulsion.

[0011] Step 2: Add wall material raw materials and alkali solution to the emulsion in step 1 at room temperature and 200-2000 rpm mechanical stirring, and react for 2-5 hours.

[0012] Step 3: Filter the oil phase, collect the microcapsules, rinse them repeatedly with an organic solvent, and then place them in a constant temperature drying oven at 60-100° C. for 4-8 hours to obtain silica microcapsules with carbon dioxide adsorption capacity.

[0013] Furthermore, in step 1, the mass ratio of the kerosene, the organic amine and the surfactant is preferably 30 to 50:10 to 50:1.

[0014] Further, in step 1, it is preferred that the surfactant is any one of Span 85, polyglycerol ricinoleate, Tween 20, Tween 21, Tween 40, Tween 60, Tween 80, and Tween 85.

[0015] Further, in step 2, it is preferred that the mass ratio of the wall material raw material to the lye is 1-5:1.

[0016] Further, in step 2, it is preferred that the lye is an aqueous solution of any one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate, and the mass concentration of the lye is 0.1%-5%.

[0017] Further, in step 2, it is preferred that the mass ratio of the wall material raw material to the emulsion is 1:2-6.

[0018] Further, in step 2, it is preferred that the organic solvent is any one of kerosene, mineral oil, ethyl acetate, petroleum ether, n-hexane, cyclohexane, and n-butane.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. First, the organic amine is dispersed in kerosene in the present invention. Due to the presence of the surfactant, the organic amine is wrapped by kerosene to form tiny W / O droplets. The addition of the base promotes the hydrolysis and polymerization of silicon sources such as tetraethyl orthosilicate, and a silica shell is formed on the outer layer of the droplets, wrapping the organic amine to form microcapsules. The preparation process of the microcapsules of the present invention is simple, the raw material sources are wide, the process conditions are mild, the microcapsules are uniform in size, the particle size is 200-350 μm, its adsorption capacity can be regulated according to the type of organic amine added, and the wall thickness of the capsule can be adjusted by the addition amount of silicon sources such as tetraethyl orthosilicate.

[0021] 2. The microcapsules prepared by the present invention are a kind of efficient and reusable carbon dioxide adsorbent material. It can be directly placed in the CO 2 gas stream, and efficient adsorption is achieved through the chemical action between the internal adsorbent and CO 2 molecules. The maximum adsorption amount of CO 2 can reach 3.46 mmol / g, and good performance can still be maintained at a low temperature of -30°C. In addition, the thermal decomposition temperature of the microcapsules reaches 250°C, and under the heating condition of 60-80°C, the microcapsules can quickly release the adsorbed CO 2 and achieve regeneration, so as to be recycled multiple times, and excellent thermal stability and reusability are still shown after being recycled more than 60 times.

[0022] 3. The present invention uses silica as the outer shell of the microcapsules, which has the advantages of stable chemical properties, good biocompatibility, high temperature resistance, insoluble in water, easy storage, corrosion resistance, etc., and its pore structure can allow CO 2The molecules pass through and react with the internal adsorbent, thus achieving efficient adsorption and desorption functions, which can be used for CO 2 Adsorption, storage and separation of gases. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the microscopic morphology of the silicon dioxide microcapsule with ethanolamine as the capsule core prepared in Example 1.

[0024] Figure 2 The CO of the silica microcapsules with diglycolamine as the capsule core prepared in Example 2 2 Adsorption capacity.

[0025] Figure 3 The CO of the silica microcapsules with 2-amino-2-methyl-1-propanol as the capsule core prepared in Example 5 2 Adsorption capacity.

[0026] Figure 4 This is a graph showing the cyclic adsorption and desorption performance of the silica microcapsules prepared in Example 2 with diglycolamine as the capsule core.

[0027] Figure 5 This is a graph of the cyclic adsorption and desorption performance of the silica microcapsules prepared in Example 5 with 2-amino-2-methyl-1-propanol as the capsule core.

[0028] Figure 6 It is a graph of the low temperature adsorption performance of the microcapsules prepared in Examples 1 to 4.

[0029] Figure 7 This is a thermal decomposition curve of the silicon dioxide microcapsules prepared in Example 1 with ethanolamine as the capsule core.

[0030] Figure 8 This is a thermal decomposition curve of the silicon dioxide microcapsules prepared in Example 2 with diglycolamine as the capsule core. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0032] Example 1

[0033] Step 1: Mix 50g kerosene, 10g monoethanolamine and 1g Span 85 and disperse them thoroughly to make an emulsion.

[0034] Step 2: Add 10 g of tetraethyl silicate and 2 g of a 1% sodium hydroxide aqueous solution to the emulsion prepared in step 1 at room temperature with a stirring speed of 400 rpm and react for 3 h.

[0035] Step 3: Filter the oil phase, collect the microcapsules and rinse them three times with petroleum ether, place them in a constant temperature drying oven with a forced draft at 60°C for 4 hours, and obtain silica microcapsules with ethanolamine as the capsule core (see Figure 1 ).

[0036] Example 2

[0037] Step 1: Mix 25g kerosene, 10g diglycolamine and 0.5g Tween 85 and disperse them fully to make an emulsion.

[0038] Step 2: Add 12 g of tetraethyl silicate and 3 g of a 0.5% aqueous potassium hydroxide solution to the emulsion prepared in step 1 at room temperature with a stirring speed of 1200 rpm and allow to react for 5 h.

[0039] Step 3: Filter the oil phase, collect the microcapsules and rinse them with petroleum ether three times, put them into a constant temperature drying oven with a forced draft at 80° C. and dry them for 6 hours to obtain silica microcapsules with diglycolamine as the capsule core.

[0040] Example 3

[0041] Step 1: Mix 45 g of kerosene, 15 g of piperazine (first heated to melt at 150° C.), and 1.5 g of Span 85, and disperse them fully to prepare an emulsion.

[0042] Step 2: Add 15 g of tetraethyl silicate and 3 g of a 0.2% sodium carbonate aqueous solution to the emulsion prepared in step 1 at room temperature with a stirring speed of 800 rpm and allow to react for 3 h.

[0043] Step 3: Filter the oil phase, collect the microcapsules and rinse them with petroleum ether three times, put them into a constant temperature drying oven with a forced draft at 80° C. and dry them for 6 h to obtain silica microcapsules with piperazine as the capsule core.

[0044] Example 4

[0045] Step 1: Mix 30g kerosene, 20g diisopropanolamine and 1g Tween 40 and disperse them fully to make an emulsion.

[0046] Step 2: Add 10 g of tetraethyl silicate and 10 g of a 0.1% potassium hydroxide aqueous solution to the emulsion prepared in step 1 at room temperature with a stirring speed of 600 rpm and react for 4 h.

[0047] Step 3: Filter the oil phase, collect the microcapsules and rinse them with petroleum ether three times, put them into a constant temperature drying oven with a forced draft at 100° C. for 8 h, and obtain silica microcapsules with diisopropanolamine as the capsule core.

[0048] Example 5

[0049] Step 1: Mix 60 g of kerosene, 20 g of 2-amino-2-methyl-1-propanol and 2 g of Span 85, and disperse them thoroughly to prepare an emulsion.

[0050] Step 2: Add 20 g of tetraethyl silicate and 10 g of a 5% sodium hydroxide aqueous solution to the emulsion prepared in step 1 at room temperature with a stirring speed of 400 rpm and allow to react for 3 h.

[0051] Step 3: Filter the oil phase, collect the microcapsules and rinse them with petroleum ether three times, put them into a forced air constant temperature drying oven at 80° C. and dry them for 6 h to obtain silica microcapsules with 2-amino-2-methyl-1-propanol as the capsule core.

[0052] The specific surface area, pore volume and pore diameter of the microcapsules prepared in Examples 2 and 5 above were tested. The results are shown in Table 1.

[0053] Table 1 Pore size data of silica microcapsules

[0054]

[0055] The coating quality of the organic amine in the microcapsules prepared in Examples 1 to 5 above was tested, and the coating rate of the organic amine was calculated. The results are shown in Table 2.

[0056] Table 2 Coverage rate data of silica microcapsules

[0057]

[0058] The CO of the microcapsules prepared in the above examples was further investigated. 2 The adsorption and desorption capacity, cyclic adsorption and desorption capacity, low temperature adsorption capacity and thermal stability were tested. The results are shown in Figures 2 to 8 .

[0059] Figure 2 and Figure 3 The CO of the silica microcapsules with diglycolamine as the capsule core in Example 2 and the silica microcapsules with 2-amino-2-methyl-1-propanol as the capsule core in Example 5 are shown respectively. 2 Adsorption and desorption capacity curve, in CO 2 In the adsorption and desorption capacity test, under room temperature, the adsorption pressure is a standard atmospheric pressure. Before the test, the microcapsules need to be degassed at 60°C for 8 hours to remove the impurities contained in the microcapsules, and then CO is introduced. 2The gas was tested. The results showed that the silica microcapsules with diethanolamine as the core exhibited a higher adsorption capacity, reaching 3.46 mmol / g, which was significantly higher than that of the silica microcapsules with 2-amino-2-methyl-1-propanol as the core, which was 0.97 mmol / g. From the adsorption curve, the adsorption process of the silica microcapsules with diethanolamine as the core was relatively stable, while the adsorption curve of the silica microcapsules with 2-amino-2-methyl-1-propanol as the core was relatively steep.

[0060] Figure 4 and Figure 5 shows the cyclic adsorption and desorption capacities of the silica microcapsules with diethanolamine as the core in Example 2 and the silica microcapsules with 2-amino-2-methyl-1-propanol as the core in Example 5. Both types of microcapsules can achieve multiple cycles of adsorption, and the silica microcapsules with diethanolamine as the core are particularly prominent. Under the heating condition of 60-80 °C, the silica microcapsules with diethanolamine as the core can achieve more than 60 cycles of adsorption, fully demonstrating the excellent cyclic adsorption performance of the silica microcapsules.

[0061] Figure 6 shows the low-temperature adsorption performance of the silica microcapsules prepared in Examples 1-4. In the low-temperature adsorption test, a low-temperature cooling bath was used, and the cooling rate was set at 0.5 °C / min. The adsorption capacities of the microcapsules at -10 °C, -20 °C, -30 °C and -40 °C were measured respectively. Each type of microcapsule was placed at low temperature to adsorb CO 2 for 1 hour, and then the weight increase was measured and the CO 2 adsorption capacity was calculated. The results showed that all four types of microcapsules maintained good adsorption capacity at low temperature, and the adsorption rate was above 10%. Among them, the silica microcapsules with piperazine as the core were particularly prominent, with the highest adsorption capacity reaching 18%, and showing excellent stability and continuous adsorption capacity.

[0062] Figure 7 and Figure 8The thermal decomposition curves of the silica microcapsules with ethanolamine as the capsule core prepared in Example 1 and the silica microcapsules with diglycolamine as the capsule core prepared in Example 2 are respectively shown. In the thermal analysis experiment, the thermal stability and weight loss of the microcapsules were tested and analyzed using a thermogravimetric analyzer and a differential scanning calorimeter. The experimental temperature of the thermogravimetric analyzer was set to 30-600°C, the heating rate was 20°C / min, and the nitrogen atmosphere; the experimental temperature of the differential scanning calorimeter was set to 30-300°C, the heating rate was 20°C / min, and the nitrogen atmosphere. The thermal properties of the microcapsules were determined by analyzing the thermal decomposition and heat flow curves of the samples. As can be seen from the figure, the thermal decomposition curve is roughly divided into two parts, located at 130°C and 180°C respectively. At 130°C, the weight of the microcapsules increased slightly due to the reaction with oxygen in the air; as the temperature further increased, the mass of the microcapsules gradually decreased. When the temperature reached 180°C, the mass change was significant, at which time the shell material of the microcapsules began to decompose, and the excess shell material attached to the surface was removed by evaporation. According to the differential thermogravimetric analysis (DTG) curve, when the attachments on the surface of the microcapsules are completely removed, the weight loss rate will reach the maximum value. When the temperature rises to 300°C, the mass of the microcapsules no longer changes significantly. These experimental data show that the microcapsules prepared by this method have good thermal stability.

Claims

1. A silicon dioxide microcapsule having carbon dioxide adsorption capacity, characterized in that: The microcapsule is prepared by using any one of tetraethyl silicate and phenyltriethoxysilane as the wall material and by using an interfacial polymerization method. The microcapsule has silicon dioxide as the capsule wall and organic amine as the capsule core.

2. The silicon dioxide microcapsule having carbon dioxide adsorption capacity according to claim 1, characterized in that: The organic amine is selected from any one or more of ethanolamine, diglycolamine, 2-amino-2-methyl-1-propanol, piperazine, diisopropanolamine, triethylenetetramine, tetraethylenepentamine and 1,3-propylenediamine.

3. A method for preparing silicon dioxide microcapsules having carbon dioxide adsorption capacity according to claim 1 or 2, characterized in that The method comprises the following steps: Step 1: Mix kerosene, organic amine and surfactant, fully disperse them and prepare an emulsion; Step 2: Add wall material raw materials and alkali solution to the emulsion in step 1 at room temperature and 200-2000 rpm mechanical stirring, and react for 2-5 hours; Step 3: Filter the oil phase, collect the microcapsules, rinse them repeatedly with an organic solvent, and then place them in a constant temperature drying oven at 60-100° C. for 4-8 hours to obtain silica microcapsules with carbon dioxide adsorption capacity.

4. The method for preparing silicon dioxide microcapsules having carbon dioxide adsorption capacity according to claim 3, characterized in that: In step 1, the mass ratio of the kerosene, the organic amine and the surfactant is 30-50:10-50:

1.

5. The method for preparing silicon dioxide microcapsules having carbon dioxide adsorption capacity according to claim 3, characterized in that: In step 1, the surfactant is selected from any one of Span 85, polyglycerol ricinoleate, Tween 20, Tween 21, Tween 40, Tween 60, Tween 80, and Tween 85.

6. The method for preparing silicon dioxide microcapsules having carbon dioxide adsorption capacity according to claim 3, characterized in that: In step 2, the mass ratio of the wall material raw material to the alkali solution is 1 to 5:

1.

7. The method for preparing silicon dioxide microcapsules having carbon dioxide adsorption capacity according to claim 6, characterized in that: In step 2, the alkali solution is selected from an aqueous solution of any one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, and the mass concentration of the alkali solution is 0.1% to 5%.

8. The method for preparing silicon dioxide microcapsules having carbon dioxide adsorption capacity according to claim 3, characterized in that: In step 2, the mass ratio of the wall material raw material to the emulsion is 1:2-6.

9. The method for preparing silicon dioxide microcapsules having carbon dioxide adsorption capacity according to claim 3, characterized in that: In step 2, the organic solvent is selected from any one of kerosene, mineral oil, ethyl acetate, petroleum ether, n-hexane, cyclohexane, and n-butane.

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