A hyperbranched Pickering microsphere adsorbent and its preparation method and application

Abstract

To solve the problems of low efficiency and poor specificity of traditional adsorption materials for CO2, the present invention provides a hyperbranched Pickering microsphere adsorbent, its preparation method and application. The adsorbent has rich branched chains, no entanglement between molecules, and a large number of terminal amino groups, so that it can adsorb CO2 with high adsorption capacity and high selectivity, achieving the purpose of purifying flue gas, and has the advantages of fast adsorption rate and low desorption energy consumption, fundamentally solving the problems of low adsorption efficiency and poor selectivity of traditional materials.

Description

Technical Field

[0001] The invention belongs to the technical field of adsorption materials, and particularly relates to a hyperbranched Pickering microsphere adsorbent and a preparation method and application thereof. Background Art

[0002] Climate change caused by the greenhouse effect has become one of the core issues of the current global environment. Studies have shown that the main factor causing the temperature rise is carbon dioxide (CO 2 ) content, so it is necessary to develop efficient and complete processes and methods for CO 2 The capture of carbon dioxide is attracting increasing attention. In theory, the main way to deal with global warming is to reduce carbon dioxide emissions.

[0003] Considering the characteristics of the current energy structure and the high cost of developing and utilizing new energy, the combustion of fossil fuels will remain the main source of energy for a long time in the future. 2 Capture and storage technology (CO 2 capture and storage (CCS) will be a key step in stabilizing atmospheric CO 2 The most feasible scenario for the concentration of CO 2 Capture and storage technology refers to the use of CO2 at the source of emission. 2 Capture, transport to storage sites, and injection into geology or the ocean for storage.

[0004] Among them, the solid adsorption method does not involve the participation of solvents, which can avoid the construction cost problem caused by equipment corrosion and the additional energy consumption problem caused by solvent evaporation; moreover, CO 2 The molecules can directly contact with the active groups on the adsorbent material, reducing a mass transfer interface, which also reduces the energy required to overcome the interfacial tension. Therefore, adsorption separation has greater energy-saving potential. However, at this stage, whether it is pressure swing physical adsorption or temperature swing chemical adsorption, energy consumption is still high. The core problem is that the comprehensive performance of the adsorption material cannot meet the actual needs. The ideal adsorption material should have the following characteristics: high adsorption capacity and CO 2 / N 2 It has the characteristics of selectivity, tolerance to impurities, fast adsorption and desorption kinetics, good morphological and chemical stability, good wear resistance in fluidized beds, low regeneration energy consumption and equipment cost.

[0005] Therefore, how to obtain an ideal adsorption material with the above-mentioned comprehensive properties is a problem that needs to be solved. Summary of the invention

[0006] In view of the problems existing in the prior art, the object of the present invention is to provide a hyperbranched Pickering microsphere adsorbent and a preparation method and application thereof, wherein the hyperbranched Pickering microsphere adsorbent is used for the adsorption of carbon dioxide, and can achieve the adsorption of CO2 in the atmosphere. 2 Efficient and highly selective adsorption of pollutants.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] The first aspect of the present invention provides a method for preparing a hyperbranched Pickering microsphere adsorbent, comprising the following steps:

[0009] (1) First, 0.4-0.5 g of 1-dodecanol, 20-23 mg of azobisbutyronitrile, 1-2 mL of toluene, 2-3 mmol of 2-(diethylamino)ethyl methacrylate and 7-9 mmol of divinylbenzene are weighed in a test tube, mixed by vortexing, referred to as solution A, and nitrogen is continuously introduced into solution A; then 80-140 mg of silica balls are mixed with 10 mL of pure water in a test tube, and ultrasonically treated for 1-2 min, referred to as solution B; solution A is added to solution B, and the mixture is homogenized to obtain a Pickering emulsion; the Pickering emulsion is placed in a water bath at 60-80° C. for polymerization reaction for 20-24 h; after the reaction, the composite material obtained by filtration is soaked in an acidic solution, then filtered and washed with deionized water until the composite material is neutral; methanol is used as an extraction solvent, and Soxhlet extraction is performed for 10-15 h to remove unreacted impurities in the composite material, thereby obtaining a Pickering microsphere material;

[0010] (2) dispersing a mixture of 10 to 30 g of the Pickering microsphere material obtained in step (1) and 20 to 60 g of an epoxy silane coupling agent in 10 to 100 mL of anhydrous toluene, refluxing at 100 to 140° C. for 4 to 8 h under inert gas protection, filtering, washing the resulting precipitate with anhydrous toluene and ethanol, and drying to obtain epoxy-modified Pickering microspheres;

[0011] (3) dissolving 2-50 g of polyethyleneimine in 50-500 mL of a methanol / water mixture, adding 5-50 g of the epoxy-modified Pickering microspheres obtained in step (2), and then reflux reacting at 60-100° C. for 4-8 h. After evaporating the solvent, amino-modified Pickering microspheres are obtained, which are the hyperbranched Pickering microsphere adsorbent.

[0012] Further, in step (1), the acidic solution includes HCl aqueous solution, HF aqueous solution and HNO 3 Aqueous solution.

[0013] Furthermore, in step (1), the conditions for the homogenization treatment include: the speed of the homogenizer is 4000-6000 rpm, and the stirring time is 1-3 min.

[0014] Furthermore, the epoxysilane coupling agent is a mixture of any one or more of 2-(3,4-epoxycyclohexane)ethyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, and 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane.

[0015] Furthermore, the inert gas includes nitrogen, argon and helium.

[0016] Furthermore, in step (3), the polyethyleneimine is any one or a mixture of two or more of chain or branched polyethyleneimine with molecular weights of 10,000, 25,000, 70,000 and 700,000.

[0017] Furthermore, in step (3), the volume ratio of methanol to water in the methanol / water mixture is 1:5 to 5:1.

[0018] In a second aspect, the present invention provides a hyperbranched Pickering microsphere adsorbent prepared by the above preparation method.

[0019] In a second aspect of the present invention, the hyperbranched Pickering microsphere adsorbent is provided for adsorbing / capturing CO in flue gas or air. 2 Application in.

[0020] Furthermore, after 20 to 100 adsorption-desorption cycles, the hyperbranched Pickering microsphere adsorbent has a CO 2 The adsorption capacity decreased within 5%.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The preparation method of the hyperbranched Pickering microsphere adsorbent of the present invention is simple, has high yield, low raw material price, and is environmentally friendly. 2 Bottlenecks such as low efficiency and poor specificity provide new research ideas.

[0023] (2) The hyperbranched Pickering microsphere adsorbent prepared by the present invention has abundant side chains, no entanglement between molecules, and a large number of terminal amino groups, so it can adsorb CO with high adsorption capacity and high selectivity. 2 , achieving the purpose of purifying flue gas, it has the advantages of fast adsorption speed and reduced desorption energy consumption, fundamentally solving the problems of low adsorption efficiency and poor selectivity of traditional materials.

[0024] (3) The present invention explores the use of hyperbranched Pickering microsphere adsorbents to capture CO in simulated flue gas. 2 performance, has strong water vapor tolerance and cyclic stability, and its pore size is similar to CO 2molecular dynamics diameter, showing high CO 2 Adsorption selectivity.

[0025] (4) The hyperbranched Pickering microsphere adsorbent prepared by the present invention also exhibits good reusability and can be applied to large-scale CO 2 Capture items. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0027] Figure 1 Example 2: Using the hyperbranched Pickering microsphere adsorbent of the present invention to perform CO 2 Schematic diagram of the device structure for adsorption treatment;

[0028] Figure 2 The present invention is used for CO 2 Results of 40 adsorption-desorption cycles of adsorbed hyperbranched Pickering microsphere materials. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, features and effects proposed according to the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0030] Example 1

[0031] This embodiment provides a method for preparing a hyperbranched Pickering microsphere adsorbent, comprising the following steps:

[0032] (1) First, 0.422 g of 1-dodecanol, 22.5 mg of azobisbutyronitrile (AIBN), 1.2 mL of toluene, 2 mmol of 2-(diethylamino)ethyl methacrylate (DEAEMA) and 8 mmol of divinylbenzene (DVB) were weighed in a test tube and mixed by vortexing, which was called solution A. Nitrogen was continuously introduced into solution A. Then 120 mg of silica balls and 10 mL of pure water were mixed in a test tube and placed in an ultrasonic bath for 1 min, which was called solution B. Next, solution A was added to solution B, and the mixture was rapidly stirred at 6000 rpm for 1 min using a homogenizer to obtain a Pickering emulsion. The Pickering emulsion was then placed in a water bath at 60°C for 24 h to undergo polymerization. After the reaction was completed, the composite material obtained by filtration was soaked in hydrofluoric acid for 24 h, then filtered and washed with deionized water until the composite material was neutral.

[0033] Methanol was used as the extraction solvent, and Soxhlet extraction was performed at 60° C. for 12 h to remove unreacted impurities in the composite material, thereby obtaining the Pickering microsphere material.

[0034] (2) A mixture of 5 g of the Pickering microsphere material obtained in step (1) and 10 g of 3-glycidyloxypropyltriethoxysilane was dispersed in 20 mL of anhydrous toluene, heated to 100° C. and refluxed for 6 h under nitrogen protection, filtered and washed with anhydrous toluene and ethanol, and then the solid was dried in a vacuum drying oven at 80° C. for 24 h to obtain epoxy-modified Pickering microspheres.

[0035] (3) Dissolve 5 g of branched polyethyleneimine with a molecular weight of 70,000 in 50 mL of a methanol / water mixture (the volume ratio of methanol to water is 1:1), add 5 g of the epoxy-modified Pickering microspheres obtained in step (2), heat to 100° C. and reflux for 6 h under nitrogen protection, dry in a vacuum drying oven at 80° C. for 24 h to evaporate the solvent, and obtain amino-modified Pickering microspheres, i.e., the hyperbranched Pickering microsphere adsorbent.

[0036] Example 2

[0037] This embodiment provides another method for preparing a hyperbranched Pickering microsphere adsorbent, comprising the following steps:

[0038] (1) First, 0.422 g of 1-dodecanol, 22.5 mg of azobisbutyronitrile (AIBN), 1.2 mL of toluene, 2 mmol of 2-(diethylamino)ethyl methacrylate (DEAEMA) and 8 mmol of divinylbenzene (DVB) were weighed in a test tube and mixed by vortexing, which was called solution A. Nitrogen was continuously introduced into solution A. Then 80 mg of silica balls were mixed with 10 mL of pure water in a test tube and placed in an ultrasonic bath for 1 min, which was called solution B. Next, solution A was added to solution B, and the mixture was rapidly stirred at 6000 rpm for 1 min using a homogenizer to obtain a Pickering emulsion. The Pickering emulsion was then placed in a water bath at 60°C for 24 h to undergo polymerization. After the reaction was completed, the composite material obtained by filtration was soaked in hydrofluoric acid for 24 h, then filtered and washed with deionized water until the composite material was neutral.

[0039] Methanol was used as the extraction solvent and Soxhlet extraction was performed at 60° C. for 12 h to remove unreacted impurities in the composite material, thereby obtaining a Pickering microsphere material with a size different from that in Example 1.

[0040] (2) Disperse 5 g of the Pickering microsphere material obtained in step (1) and a mixture of 5 g of 3-glycidyloxypropyltriethoxysilane and 5 g of 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane in 20 mL of anhydrous toluene, heat to 100° C. and reflux for 6 h under nitrogen protection, filter and wash with anhydrous toluene and ethanol, and then dry the solid in a vacuum drying oven at 80° C. for 24 h to obtain epoxy-modified Pickering microspheres.

[0041] (3) Dissolve 5 g of branched polyethyleneimine with a molecular weight of 10,000 in 50 mL of a methanol / water mixture (the volume ratio of methanol to water is 1:1), add 5 g of the epoxy-modified Pickering microspheres obtained in step (2), heat to 100° C. and reflux for 6 h under nitrogen protection, dry in a vacuum drying oven at 80° C. for 24 h to evaporate the solvent, and obtain amino-modified Pickering microspheres, i.e., the hyperbranched Pickering microsphere adsorbent.

[0042] Example 3

[0043] In order to explore the adsorption capacity of the hyperbranched Pickering microsphere adsorbent prepared in Example 1, this example adopts Figure 1 The device shown is used to perform the following tests:

[0044] 500 mg of the hyperbranched Pickering microsphere adsorbent sample prepared in Example 1 was added to a U-shaped tube with an outer diameter of 1 cm and an inner diameter of 0.6 cm, supported by quartz wool, and connected to the injection port of a gas chromatograph. The overall experimental device is as follows: Figure 1 As shown. 2 Before adsorption analysis, the samples were degassed with 50 mL / min nitrogen at 130 °C for 1.5 h, then cooled to the test temperature and replaced with 15 vol.% CO 2 / 85vol.%N 2 The mixed gas is controlled to have a total flow rate of 20 mL / min.

[0045] The loaded adsorption materials were subjected to dynamic adsorption evaluation at different temperatures. The temperature was lowered to 30, 40, 50, 60, 70, 80, 90, and 100°C, the humidity was maintained at 50%, and the CO 2 The breakthrough curve for CO 2 The adsorption capacity of the adsorbed hyperbranched Pickering microspheres adsorbent at different temperatures, and the results showed that the optimal adsorption capacity was achieved at 50 °C.

[0046] The dynamic adsorption evaluation of the above-mentioned adsorbent materials under different relative humidity was carried out. 2 / 85%vol.N 2 Water vapor was introduced into the carrier gas, and the humidity was set to 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%, respectively. The temperature was maintained at 50°C, and the relative humidity of the gas was adjusted to measure CO 2 Breakthrough curve, thus calculating the CO 2 The adsorption capacity of the adsorbed hyperbranched Pickering microsphere adsorbent at different relative humidity. The results show that the adsorption capacity is higher and the difference is not large when the humidity is 50%-100%.

[0047] The above loaded adsorbent material was subjected to 40 CO 2 Adsorption and desorption cycles were performed to evaluate the CO 2 Adsorption-desorption cycle performance. At 75°C, from 60 mL / min of 15 vol.% CO 2 / 85vol.%N 2 CO in mixed gas 2 Adsorption. At 130 °C with 100 mL / min N 2 Conduct CO 2 Desorption. Figure 2 For 40 times CO 2 During the adsorption-desorption cycle, CO 2 Changes in adsorption amount. During the adsorption and desorption process, the decomposition and volatilization of the active components of the adsorbent and the CO 2 The incomplete desorption will reduce the adsorption active sites in the adsorbent, which will slightly reduce the amount of carbon dioxide adsorption. 2 Adsorption-desorption cycle, still with high CO 2 The adsorption capacity indicates that the adsorbent has relatively good stability.

[0048] In summary, the method for preparing CO 2 The adsorbed hyperbranched Pickering microsphere adsorbent has the advantages of high stability, excellent adsorption performance, fast adsorption rate and reduced desorption energy consumption, and shows good reusability, which can be applied to large-scale CO 2 Capture items.

[0049] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred arrangement scheme, a person skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a hyperbranched Pickering microsphere adsorbent, characterized in that: The preparation method comprises the following steps: (1) First, 1-dodecanol, azobisisobutyronitrile, toluene, 2-(diethylamino)ethyl methacrylate and divinylbenzene are weighed in a test tube, mixed by vortex, referred to as solution A, and nitrogen is continuously introduced into solution A; then, silicon spheres and pure water are mixed in a test tube, and ultrasonic treatment is performed for 1-2 min, referred to as solution B; solution A is added to solution B, and the mixture is homogenized to obtain a Pickering emulsion; the Pickering emulsion is placed in a water bath at 60-80°C for polymerization for 20-24 h; after the reaction is completed, the composite material obtained by filtration is soaked in an acidic solution, then filtered and washed with deionized water until the composite material is neutral; methanol is used as an extraction solvent, and Soxhlet extraction is performed for 10-15 h to remove unreacted impurities in the composite material, thereby obtaining a Pickering microsphere material; (2) dispersing the mixture of the Pickering microsphere material and the epoxy silane coupling agent obtained in step (1) in anhydrous toluene, refluxing at 100-140° C. for 4-8 h under inert gas protection, filtering, washing the obtained precipitate with anhydrous toluene and ethanol, and drying to obtain epoxy-modified Pickering microspheres; The epoxy silane coupling agent is a mixture of any one or more of 2-(3,4-epoxycyclohexane)ethyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, and 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane; (3) Dissolving polyethyleneimine in a methanol / water mixture, adding the epoxy-modified Pickering microspheres obtained in step (2), and then reflux reacting at 60-100° C. for 4-8 h. After evaporating the solvent, amino-modified Pickering microspheres are obtained, which are the hyperbranched Pickering microsphere adsorbent.

2. The method for preparing the hyperbranched Pickering microsphere adsorbent according to claim 1, characterized in that: In step (1), the acidic solution includes HCl aqueous solution, HF aqueous solution and HNO3 aqueous solution.

3. The method for preparing the hyperbranched Pickering microsphere adsorbent according to claim 1, characterized in that: In step (1), the conditions for the homogenization treatment include: the speed of the homogenizer is 4000-6000 rpm, and the stirring time is 1-3 min.

4. The method for preparing the hyperbranched Pickering microsphere adsorbent according to claim 1, characterized in that: In step (2), the inert gas includes argon and helium.

5. The method for preparing the hyperbranched Pickering microsphere adsorbent according to claim 1, characterized in that: In step (3), the polyethyleneimine is any one of chain or branched polyethyleneimine with molecular weights of 10,000, 25,000, 70,000 and 700,000, or a mixture of two or more thereof.

6. The method for preparing the hyperbranched Pickering microsphere adsorbent according to claim 1, characterized in that: In step (3), the volume ratio of methanol to water in the methanol / water mixture is 1:5 to 5:

1.

7. A hyperbranched Pickering microsphere adsorbent prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the hyperbranched Pickering microsphere adsorbent according to claim 7 in adsorbing / capturing CO2 in flue gas or air.

9. The use according to claim 8, characterized in that: After 20 to 100 adsorption-desorption cycles, the CO2 adsorption capacity of the hyperbranched Pickering microsphere adsorbent decreases within 5%.

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