Waste plastic derived porous carrier as well as preparation method and application thereof

Abstract

The invention provides a waste plastic derived porous carrier as well as a preparation method and application thereof, and belongs to the technical field of preparation of carbon dioxide adsorbents. According to the invention, the porous carrier is prepared by using the waste plastic as the raw material, and the carrier can have very good adsorption performance through simple chemical modification and high-temperature treatment, so that not only is the synthesis cost of the porous carrier greatly reduced, but also the upgrading and utilization means of the waste plastic are enriched, and the resource reutilization of the waste plastic is realized. The prepared waste plastic derived porous carrier has a very good loading effect on an organic amine reagent, and the loading capacity of the organic amine reagent can be remarkably improved, so that the solid amine adsorbent obtained by loading has relatively high carbon dioxide adsorption capacity, and meanwhile, the solid amine adsorbent has excellent environmental and economic performance. The technical scheme provided by the invention is expected to cope with two environmental problems of global climate warming and plastic solid waste pollution.

Description

Technical Field

[0001] The invention relates to the technical field of carbon dioxide adsorbent preparation, and in particular to a waste plastic derived porous carrier and a preparation method and application thereof. Background Art

[0002] The large-scale emission of greenhouse gases, mainly CO2, has caused the global climate problem to become increasingly serious. In order to achieve the 1.5℃ target of the Paris Agreement, CO2 emission reduction is urgent. Carbon capture, utilization and storage technology plays a key role in carbon emission reduction. Direct air carbon capture technology is a negative emission technology that directly removes CO2 from the atmosphere through carbon capture materials. Due to the flexibility of equipment layout, direct air carbon capture can eliminate the cost of transporting carbon to storage or utilization sites, and is a potential carbon capture route. At present, the capture methods of direct air carbon capture are divided into two categories: solution absorption and solid adsorption. The use of organic amine solution to absorb CO2 has been widely used in flue gas carbon capture, but the high gas processing volume demand of direct air carbon capture makes the solution absorption technology have problems such as large volatilization of amine liquid and significant increase in capture cost. Compared with the solution absorption method, solid material adsorption avoids the high amount of heat for heating the absorption solution, has obvious advantages in reducing equipment corrosion and anti-degradation, and can effectively reduce amine volatilization and water loss. At present, solid adsorbents for direct air carbon capture mainly include solid amine adsorbents, physical adsorbents, alkaline earth metal-based adsorbents and humidifying adsorbents.

[0003] Solid amine adsorbents are currently the most mature type of direct air carbon capture solid materials. The preparation method of this type of material is to use amines as the active ingredient for CO2 adsorption and load them on a porous carrier with a suitable structure to prepare a solid amine material. There are three ways to load amine reagents on porous carriers, including physical impregnation, chemical grafting and in-situ polymerization. Among them, the physical impregnation method is the most widely used due to its simple process and considerable loading capacity. Among them, PEI and TEPA are the two most commonly used amine reagents.

[0004] At present, the porous carriers commonly used for loading amine groups mainly include mesoporous silicon-based materials, composite metal oxides and porous resins. Mesoporous silicon-based materials are the most widely used. Such carriers have uniform mesopore diameters, and the amine loading performance of silicon-based carriers has been widely verified. However, the synthesis of silicon-based mesoporous carriers mainly uses the template method, and its synthesis cost remains high, which restricts the large-scale application of amine-loaded adsorbents. Therefore, the development of a carrier with high adsorption capacity, low synthesis cost and good recycling is crucial for carbon dioxide capture, and has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a waste plastic derived porous carrier and a preparation method and application thereof. The waste plastic derived porous carrier prepared by the preparation method provided by the present invention has a large specific surface area, multiple pore structures, good loading effect on organic amines, low cost and good recycling.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a waste plastic-derived porous carrier, comprising the following steps:

[0008] (1) crushing waste plastics to obtain plastic powder, and then mixing the plastic powder with a chemical modifier to obtain a mixture; the chemical modifier includes any one of a solid base, an alkaline solution and an acid solution;

[0009] (2) heat-treating the mixture obtained in step (1) to obtain a waste plastic-derived porous carrier.

[0010] Preferably, the waste plastic in step (1) is PET plastic.

[0011] Preferably, the particle size of the plastic powder in step (1) is ≥40 mesh.

[0012] Preferably, in step (1), the solid base is potassium hydroxide or sodium hydroxide; the alkaline solution is potassium hydroxide solution or sodium hydroxide solution, and the concentration of the alkaline solution is 0.5-0.8 g / mL; the acid solution is phosphoric acid solution, and the mass concentration of the phosphoric acid solution is 80-85%.

[0013] Preferably, when the chemical modifier in step (1) is a solid base, the mass ratio of the plastic powder to the solid base is 1:(1-5).

[0014] Preferably, when the chemical modifier in step (1) is an alkaline solution, the ratio of the mass of the plastic powder to the volume of the alkaline solution is (2-5) g: (8-15) mL.

[0015] Preferably, when the chemical modifier in step (1) is an acid solution, the mass ratio of the plastic powder to the acid solution is 1:(1-5).

[0016] Preferably, the heat treatment temperature in step (2) is 600-800°C, and the heat treatment time is 0.2-3h; the heating rate to the heat treatment temperature is 3-10°C / min; the heat treatment atmosphere is nitrogen, and the nitrogen flow rate is 100-300mL / min.

[0017] The present invention provides a waste plastic derived porous carrier prepared by the preparation method described in the above technical solution, wherein the waste plastic derived porous carrier has a BET specific surface area of ​​800 to 1100 m 2 ·g -1 The total pore volume of the waste plastic-derived porous carrier is 1.25-1.45 mL g -1 The BJH pore volume of the waste plastic derived porous carrier is 0.85-1.15 cm 3 / g, the HK method micropore volume of the waste plastic derived porous carrier is 0.44~0.5cm 3 / g, the BJH average pore diameter (4V / A) of the waste plastic derived porous carrier is 10-20nm.

[0018] The present invention provides the use of the waste plastic-derived porous carrier described in the above technical solution in the preparation of a solid amine adsorbent.

[0019] The present invention provides a method for preparing a waste plastic derived porous carrier, comprising the following steps: (1) crushing waste plastic to obtain plastic powder, and then mixing the plastic powder with a chemical modifier to obtain a mixture; the chemical modifier includes any one of a solid base, an alkaline solution and an acid solution; (2) subjecting the mixture obtained in step (1) to heat treatment to obtain a waste plastic derived porous carrier. The present invention prepares a porous carrier using waste plastic as a raw material, and through simple chemical modification and high temperature treatment, the carrier can have good adsorption performance, which not only greatly reduces the synthesis cost of the porous carrier, but also enriches the means of upgrading and utilizing waste plastics, and realizes the resource recycling of waste plastics. The waste plastic derived porous carrier prepared by the present invention has a good loading effect on organic amine reagents, and can significantly increase the loading amount of organic amine reagents, so that the obtained solid amine adsorbent has a higher carbon dioxide adsorption amount, and has excellent environmental and economic performance. The technical solution provided by the present invention is expected to simultaneously address the two major environmental problems of global warming and plastic solid waste pollution. The results of the embodiment show that the BET specific surface area of ​​the waste plastic derived porous carrier prepared by the preparation method provided by the present invention is 800-1100m 2 ·g -1 The total pore volume of the waste plastic-derived porous carrier is 1.25-1.45 mL g -1 The BJH pore volume of the waste plastic derived porous carrier is 0.85-1.15 cm 3 / g, the HK method micropore volume of the waste plastic derived porous carrier is 0.44~0.5cm 3 / g, the BJH average pore diameter (4V / A) of the waste plastic derived porous carrier is 10-20nm; the solid amine adsorbent prepared by using the waste plastic derived porous carrier provided by the present invention has an adsorption capacity of 1.33mmol / g at 25°C and atmospheric CO2 partial pressure (i.e. 40Pa), and has a high direct air carbon capture capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the carbon dioxide adsorption isotherm of the solid amine adsorbent prepared in Application Example 1. DETAILED DESCRIPTION

[0021] The present invention provides a method for preparing a waste plastic-derived porous carrier, comprising the following steps:

[0022] (1) crushing waste plastics to obtain plastic powder, and then mixing the plastic powder with a chemical modifier to obtain a mixture; the chemical modifier includes any one of a solid base, an alkaline solution and an acid solution;

[0023] (2) heat-treating the mixture obtained in step (1) to obtain a waste plastic-derived porous carrier.

[0024] The invention crushes waste plastics to obtain the plastic powder, and then mixes the plastic powder with a chemical modifier to obtain a mixture.

[0025] In the present invention, the waste plastic is preferably PET plastic. The present invention has no particular limitation on the specific source of the waste plastic, and the waste PET plastic well known to those skilled in the art can be recycled.

[0026] The present invention preferably washes the waste plastics and then crushes them. The present invention has no particular limitation on the specific operation of the washing, as long as the impurities on the waste plastics can be removed.

[0027] In the present invention, the pulverization method is preferably: firstly, the waste plastic is cut into pieces, then immersed in liquid nitrogen, then pulverized, and finally sieved to obtain plastic powder.

[0028] The present invention has no special limitation on the specific operation of the shredding, as long as the size of the shredded plastic meets the requirements. In an embodiment of the present invention, the shredded plastic is 5mm*5mm diamond-shaped fragments.

[0029] In the present invention, the immersion time in liquid nitrogen is preferably 0.5 to 3 minutes. By immersing the plastic in liquid nitrogen, the brittleness of the plastic can be increased, making it easier to form fine powder during subsequent crushing. As an embodiment of the present invention, the immersion time can be 0.5 minutes, 1 minute, 2 minutes or 3 minutes.

[0030] In the present invention, the pulverization is preferably carried out in a pulverizer. The present invention has no particular limitation on the specific model and source of the pulverizer, and a commercially available pulverizer known to those skilled in the art can be used. The present invention has no particular limitation on the pulverization time, and it only needs to be able to make the particle size of the plastic powder meet the requirements. As an embodiment of the present invention, the pulverization time can be 30 seconds, 1 minute or 2 minutes.

[0031] In the present invention, the sieving is preferably through a 40-mesh sieve. In the present invention, the particle size of the plastic powder is preferably ≥ 40 mesh. The present invention can ensure that the subsequent chemical modifier fully modifies the plastic powder by controlling the particle size of the plastic powder.

[0032] In the present invention, the chemical modifier includes any one of a solid base, an alkaline solution and an acid solution; the solid base is preferably potassium hydroxide or sodium hydroxide, more preferably potassium hydroxide; the alkaline solution is preferably a potassium hydroxide solution or a sodium hydroxide solution, more preferably a potassium hydroxide solution; the solvent of the alkaline solution is water; the concentration of the alkaline solution is preferably 0.5-0.8 g / mL, more preferably 0.6 g / mL; the acid solution is preferably a phosphoric acid solution; the solvent of the acid solution is water; the mass concentration of the phosphoric acid solution is preferably 80-85%, more preferably 85%.

[0033] In the present invention, when the chemical modifier is a solid base, the mass ratio of the plastic powder to the solid base is preferably 1: (1-5), more preferably 1: (2-4), and further preferably 1: (2-3). In the present invention, the mixing of the plastic powder and the solid base is preferably carried out in a blender. The present invention has no special restrictions on the specific model and source of the blender, and a commercially available blender familiar to those skilled in the art can be used. The present invention has no special restrictions on the rotation speed and time of the stirring, and it is sufficient to break up the solid base and mix it evenly with the plastic powder. In an embodiment of the present invention, the stirring and mixing time can be 10s.

[0034] In the present invention, when the chemical modifier is an alkaline solution, the ratio of the mass of the plastic powder to the volume of the alkaline solution is preferably (2-5) g: (8-15) mL, and more preferably (3-4) g: (10-12) mL. In the present invention, the mixing method of the plastic powder and the alkaline solution is preferably: after the plastic powder and the alkaline solution are mixed, magnetic stirring is performed, and then drying is performed. In the present invention, the temperature of the magnetic stirring is preferably 50-80°C; the time of the magnetic stirring is preferably 1-6 hours; the temperature of the drying is preferably 70-80°C; and the time of the drying is preferably 8-12 hours. As an embodiment of the present invention, the temperature of the magnetic stirring can be 60-70°C; the time of the magnetic stirring can be 2-5 hours, and can also be 3-4 hours; the time of the drying can be 9-11 hours, and can also be 10 hours.

[0035] In the present invention, when the chemical modifier is an acid solution, the mass ratio of the plastic powder to the acid solution is preferably 1: (1-5), more preferably 1: (2-4), and further preferably 1: (2-3). In the present invention, the mixing method of the plastic powder and the acid solution is preferably: after the plastic powder and the acid solution are mixed, magnetic stirring is performed, and then drying is performed. In the present invention, the temperature of the magnetic stirring is preferably 50-80°C; the time of the magnetic stirring is preferably 1-6h; the temperature of the drying is preferably 70-80°C; and the time of the drying is preferably 8-12h. As an embodiment of the present invention, the temperature of the magnetic stirring can be 60-70°C; the time of the magnetic stirring can be 2-5h, and can also be 3-4h; the time of the drying can be 9-11h, and can also be 10h.

[0036] After obtaining the mixture, the present invention performs heat treatment on the mixture to obtain a waste plastic-derived porous carrier.

[0037] In the present invention, the heat treatment is preferably carried out in a tube furnace. The present invention has no particular limitation on the specific model and source of the tube furnace, and a commercially available tube furnace well known to those skilled in the art can be used.

[0038] In the present invention, the temperature of the heat treatment is preferably 600-800°C; the time of the heat treatment is preferably 0.2-3h; the heating rate to the heat treatment temperature is preferably 3-10°C / min; the atmosphere of the heat treatment is preferably nitrogen; the flow rate of the nitrogen is preferably 100-300mL / min. In the present invention, by heat treatment, under the action of high temperature, the chemical modifier can play a role in plasticizing the plastic powder, thereby increasing the specific surface area of ​​the carrier, and further improving the adsorption effect of the carrier.

[0039] As an embodiment of the present invention, the heat treatment temperature may be 600°C, 620°C, 650°C, 680°C, 700°C, 720°C, 750°C, 780°C or 800°C; the heat treatment time may be 0.2h, 0.5h, 1h, 1.5h, 2h, 2.5h or 3h; the heating rate to the heat treatment temperature may be 3°C / min, 4°C / min, 5°C / min, 8°C / min or 10°C / min; the nitrogen flow rate may be 100mL / min, 120mL / min, 150mL / min, 180mL / min, 200mL / min, 220mL / min, 250mL / min, 280mL / min or 300mL / min.

[0040] The present invention preferably further comprises filtering and drying the heat-treated product in sequence.

[0041] In the present invention, the suction filtration is preferably performed once with hydrochloric acid and then three times with deionized water. The present invention has no particular limitation on the specific operation of the suction filtration, and the operation well known to those skilled in the art can be used to completely remove the alkaline impurities.

[0042] The present invention has no particular limitation on the drying temperature and time, as long as the product can be completely dried. As an embodiment of the present invention, the drying temperature can be 80° C. and the drying time can be 12 hours.

[0043] The BET specific surface area of ​​the waste plastic derived porous carrier prepared by the preparation method provided by the present invention is preferably 800 to 1100 m 2 ·g -1 The total pore volume of the waste plastic derived porous carrier is preferably 1.25 to 1.45 mL·g -1 The BJH pore volume of the waste plastic derived porous carrier is preferably 0.85 to 1.15 cm 3 / g; the HK method micropore volume of the waste plastic derived porous carrier is preferably 0.44 to 0.5 cm 3 / g; the BJH average pore diameter (4V / A) of the waste plastic derived porous carrier is preferably 10 to 20 nm.

[0044] The present invention prepares a porous carrier using waste plastics as raw materials, and through simple chemical modification and high-temperature treatment, the carrier can have good adsorption performance, which not only greatly reduces the synthesis cost of the porous carrier, but also enriches the means of upgrading and utilizing waste plastics, and realizes the resource recycling of waste plastics. The waste plastic-derived porous carrier prepared by the present invention has a good loading effect on organic amine reagents, and can significantly increase the loading amount of organic amine reagents, so that the obtained solid amine adsorbent has a higher carbon dioxide adsorption amount, and has excellent environmental and economic performance. The technical solution provided by the present invention is expected to simultaneously address the two major environmental problems of global warming and plastic solid waste pollution.

[0045] The present invention also provides a waste plastic-derived porous carrier prepared by the preparation method described in the above technical solution.

[0046] The BET specific surface area of ​​the waste plastics-derived porous carrier provided by the present invention is preferably 800 to 1100 m 2 ·g -1 The total pore volume of the waste plastic derived porous carrier is preferably 1.25 to 1.45 mL·g -1 The BJH pore volume of the waste plastic derived porous carrier is preferably 0.85 to 1.15 cm 3 / g; the HK method micropore volume of the waste plastic derived porous carrier is preferably 0.44 to 0.5 cm 3 / g; the BJH average pore diameter (4V / A) of the waste plastic derived porous carrier is preferably 10 to 20 nm.

[0047] The present invention also provides the use of the waste plastics-derived porous carrier described in the above technical solution in the preparation of a solid amine adsorbent.

[0048] In the present invention, the method for preparing a solid amine adsorbent by using a porous carrier derived from waste plastics comprises:

[0049] The organic amine, the solvent and the waste plastic derived porous carrier are mixed and then subjected to rotary evaporation to obtain a solid amine adsorbent.

[0050] In the present invention, the organic amine is preferably polyethyleneimine; the solvent is preferably methanol or ethanol, more preferably methanol. In the present invention, the mass ratio of the organic amine to the waste plastic derived porous carrier is preferably 1:(1-2). By using the above organic amine, the waste plastic derived porous carrier can have better adsorption performance for the organic amine.

[0051] In the present invention, the method of mixing the organic amine, the solvent and the waste plastic-derived porous carrier is preferably: first, the organic amine and the solvent are mixed and then magnetically stirred for 10 to 30 minutes, and then the waste plastic-derived porous carrier is added and stirred for 3 to 10 hours. The present invention does not have any special limitation on the rotation speed of the magnetic stirring, which can be determined according to the technical common sense of those skilled in the art. The present invention can enable the waste plastic-derived porous carrier to fully combine with the organic amine by mixing in the above manner. As an embodiment of the present invention, the time of magnetic stirring after the organic amine and the solvent are mixed can also be 15 to 20 minutes; the time of continuous stirring after adding the waste plastic-derived porous carrier can also be 5 to 6 hours.

[0052] In the present invention, the rotary evaporation is preferably performed in a rotary evaporator. The present invention has no particular limitation on the specific model and source of the rotary evaporator, and a commercially available rotary evaporator well known to those skilled in the art can be used.

[0053] In the present invention, the temperature of the rotary evaporation is preferably 50 to 80°C; the time of the rotary evaporation is preferably 20 to 60 minutes; and the rotary evaporation is preferably carried out under the condition of water bath heating. The present invention can remove the solvent by selecting rotary evaporation. As an embodiment of the present invention, the temperature of the rotary evaporation can be 60 to 70°C; the time of the rotary evaporation can be 30 to 40 minutes.

[0054] The solid amine adsorbent prepared by using the waste plastic derived porous carrier provided by the present invention has an adsorption capacity of 1.33 mmol / g at 25° C. and atmospheric CO2 partial pressure (ie 40 Pa), and has a relatively high direct air carbon capture capacity.

[0055] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Example 1

[0057] A method for preparing a waste plastic-derived porous carrier is as follows:

[0058] (1) After cleaning, the waste plastic is cut into 5 mm*5 mm diamond-shaped pieces, then immersed in liquid nitrogen for 1 min, then crushed in a grinder for 1 min, passed through a 40-mesh sieve to obtain a plastic powder with a particle size of ≥40 mesh, and the plastic powder and a chemical modifier are mixed in a magnetic stirrer, stirred for 1 h in a 60°C water bath, and finally dried in an 80°C drying oven for 12 h to obtain a mixture; the waste plastic is PET plastic; the chemical modifier is a potassium hydroxide solution with a concentration of 0.6 g / mL; the ratio of the mass of the plastic powder to the volume of the chemical modifier is 3 g:10 mL;

[0059] (2) The mixture obtained in step (1) is heat-treated in a tubular furnace at a temperature of 700° C. for 1 h in a nitrogen atmosphere at a nitrogen flow rate of 200 mL / min. After the heat treatment, the product is naturally cooled to room temperature, filtered once with hydrochloric acid, then filtered three times with deionized water, and finally dried in a drying oven at 80° C. for 12 h to obtain a waste plastic-derived porous carrier, which is recorded as PET-K2-700.

[0060] Application Example 1

[0061] The method for preparing a solid amine adsorbent using the waste plastic-derived porous carrier provided in Example 1 is as follows:

[0062] First, polyethyleneimine and methanol are mixed in a beaker and magnetically stirred for 30 minutes. Then, a waste plastic-derived porous carrier is added. The beaker is sealed with a plastic film and stirring is continued for 6 hours. Finally, the mixture is poured into a rotary bottle and rotary evaporated in a rotary evaporator to obtain a solid amine adsorbent, which is recorded as PET-K2-700-PEI50. The mass ratio of the polyethyleneimine to the waste plastic-derived porous carrier is 1:1. The rotary evaporation temperature is 60°C, the rotary evaporation time is 30 minutes, and the rotary evaporation is carried out under water bath heating.

[0063] Example 2

[0064] A method for preparing a waste plastic-derived porous carrier is as follows:

[0065] (1) After cleaning, the waste plastic is cut into 5 mm*5 mm diamond-shaped pieces, then immersed in liquid nitrogen for 1 minute, then crushed in a grinder for 1 minute, passed through a 40-mesh sieve to obtain a plastic powder with a particle size of ≥40 mesh, and the plastic powder and a chemical modifier are stirred and mixed in a blender for 10 seconds to obtain a mixture; the waste plastic is PET plastic; the chemical modifier is potassium hydroxide; and the mass ratio of the plastic powder to the chemical modifier is 1:2;

[0066] (2) The mixture obtained in step (1) is heat-treated in a tube furnace at a temperature of 700° C. for 1 h. The heating rate to the heat treatment temperature is 5° C. / min. The atmosphere for the heat treatment is nitrogen at a flow rate of 200 mL / min. After the heat treatment, the product is naturally cooled to room temperature, filtered once with hydrochloric acid, then filtered three times with deionized water, and finally dried in a drying oven at 80° C. for 12 h to obtain a waste plastic-derived porous carrier, which is recorded as PET-K2-mix-700.

[0067] Application Example 2

[0068] The method for preparing a solid amine adsorbent using the waste plastics-derived porous carrier provided in Example 2 is as follows:

[0069] First, polyethyleneimine and methanol are mixed in a beaker and magnetically stirred for 30 minutes. Then, a waste plastic-derived porous carrier is added. The beaker is sealed with a plastic film and stirring is continued for 6 hours. Finally, the mixture is poured into a rotary bottle and rotary evaporated in a rotary evaporator to obtain a solid amine adsorbent, which is recorded as PET-K2-mix-700-PEI50. The mass ratio of the polyethyleneimine to the waste plastic-derived porous carrier is 1:1. The rotary evaporation temperature is 60°C, the rotary evaporation time is 30 minutes, and the rotary evaporation is carried out under water bath heating.

[0070] Example 3

[0071] A method for preparing a waste plastic-derived porous carrier is as follows:

[0072] (1) After cleaning the waste plastic, cut it into 5 mm*5 mm diamond-shaped pieces, then immerse it in liquid nitrogen for 1 minute, then grind it in a grinder for 1 minute, pass it through a 40-mesh sieve to obtain a plastic powder with a particle size of ≥40 mesh, mix the plastic powder with a chemical modifier in a magnetic stirrer, stir it in a 60°C water bath for 1 hour, and finally dry it in an 80°C drying oven for 12 hours to obtain a mixture; the waste plastic is PET plastic; the chemical modifier is a phosphoric acid solution, the mass concentration of the phosphoric acid solution is 85%; the mass ratio of the plastic powder to the phosphoric acid solution is 1:2;

[0073] (2) The mixture obtained in step (1) is heat-treated in a tubular furnace at a temperature of 700° C. for 1 h. The heating rate to the heat treatment temperature is 5° C. / min. The atmosphere for the heat treatment is nitrogen at a flow rate of 200 mL / min. After the heat treatment, the product is naturally cooled to room temperature, filtered once with hydrochloric acid, then filtered three times with deionized water, and finally dried in a drying oven at 80° C. for 12 h to obtain a waste plastic-derived porous carrier, which is recorded as PET-P2-700.

[0074] Application Example 3

[0075] The method for preparing a solid amine adsorbent using the waste plastic-derived porous carrier provided in Example 3 is as follows:

[0076] First, polyethyleneimine and methanol are mixed in a beaker and magnetically stirred for 30 minutes. Then, a waste plastic-derived porous carrier is added. The beaker is sealed with a plastic film and stirring is continued for 6 hours. Finally, the mixture is poured into a rotary bottle and rotary evaporated in a rotary evaporator to obtain a solid amine adsorbent, which is recorded as PET-P2-700-PEI50. The mass ratio of the polyethyleneimine to the waste plastic-derived porous carrier is 1:1. The rotary evaporation temperature is 60°C, the rotary evaporation time is 30 minutes, and the rotary evaporation is carried out under water bath heating.

[0077] The pore structure test of the waste plastics-derived porous carrier prepared in Examples 1 to 3 was conducted as follows:

[0078] 0.2 g of the waste plastic-derived porous carrier was loaded into the sample tube, and heated and vacuumed for degassing at the degassing position of the physical adsorption instrument. The heating temperature was set to 110°C, and the degassing time was 10 hours. Then, a nitrogen adsorption test was performed at the test position, and a Dewar cup filled with liquid nitrogen was used to provide a temperature environment. Pure nitrogen was introduced into the adsorption instrument, and the pressure and adsorption amount in the sample tube at equilibrium were detected. The pore structures of the waste plastic-derived porous carriers of Examples 1 to 3 obtained by the test are shown in Table 1:

[0079] Table 1 Pore structure of the waste plastics derived porous carrier of Examples 1 to 3

[0080]

[0081]

[0082] It can be seen from Table 1 that the BET specific surface area of ​​the waste plastic derived porous carrier prepared by the preparation method provided by the present invention is 800-1100 m 2 ·g -1 The total pore volume of the waste plastic derived porous carrier is 1.25 to 1.45 mL·g -1 The BJH pore volume of the waste plastic derived porous carrier is 0.85 to 1.15 cm 3 / g; the HK method micropore volume of the waste plastic derived porous carrier is 0.44 to 0.5 cm 3 / g; the BJH average pore diameter (4V / A) of the waste plastic-derived porous carrier is 10 to 20 nm.

[0083] The solid amine adsorbent PET-K2-700-PEI50 prepared in Example 1 was subjected to a carbon dioxide adsorption isotherm test, and the process was as follows:

[0084] 0.2g of solid amine adsorbent was filled in the sample tube, and heated and vacuumed for degassing at the degassing position of the physical adsorption instrument. The heating temperature was set to 110℃ and the degassing time was 5h. Then the sample tube was transferred to the test position and continued to be degassed in situ at the test position for 5h. After that, pure CO2 was introduced for adsorption test. A Dewar cup filled with 25℃ water was used to provide the temperature environment. The pressure and adsorption amount in the sample tube were tested at equilibrium. The test results are as follows: Figure 1 As shown. Figure 1 It can be seen that at 25°C and atmospheric CO2 partial pressure (i.e., 40 Pa), the solid amine adsorbent PET-K2-700-PEI50 provided in Application Example 1 of the present invention has an adsorption capacity of 1.33 mmol / g, and has a higher direct air carbon capture capacity.

[0085] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a porous carrier derived from waste plastics, comprising the following steps: (1) crushing waste plastics to obtain plastic powder, and then mixing the plastic powder with a chemical modifier to obtain a mixture; the chemical modifier includes any one of a solid base, an alkaline solution and an acid solution; (2) heat-treating the mixture obtained in step (1) to obtain a waste plastic-derived porous carrier.

2. The preparation method according to claim 1, characterized in that: The waste plastic in step (1) is PET plastic.

3. The preparation method according to claim 1, characterized in that: The particle size of the plastic powder in step (1) is ≥40 mesh.

4. The preparation method according to claim 1, characterized in that: In the step (1), the solid base is potassium hydroxide or sodium hydroxide; the alkaline solution is potassium hydroxide solution or sodium hydroxide solution, and the concentration of the alkaline solution is 0.5-0.8 g / mL; the acid solution is phosphoric acid solution, and the mass concentration of the phosphoric acid solution is 80-85%.

5. The preparation method according to claim 1, characterized in that: When the chemical modifier in step (1) is a solid base, the mass ratio of the plastic powder to the solid base is 1:(1-5).

6. The preparation method according to claim 1 or 4, characterized in that: When the chemical modifier in step (1) is an alkaline solution, the ratio of the mass of the plastic powder to the volume of the alkaline solution is (2-5) g: (8-15) mL.

7. The preparation method according to claim 1 or 4, characterized in that: When the chemical modifier in step (1) is an acid solution, the mass ratio of the plastic powder to the acid solution is 1:(1-5).

8. The preparation method according to claim 1, characterized in that: The heat treatment temperature in step (2) is 600-800°C, and the heat treatment time is 0.2-3h; the heating rate to the heat treatment temperature is 3-10°C / min; the heat treatment atmosphere is nitrogen, and the nitrogen flow rate is 100-300mL / min.

9. The waste plastic derived porous carrier prepared by the preparation method according to any one of claims 1 to 8, wherein the BET specific surface area of ​​the waste plastic derived porous carrier is 800 to 1100 m 2 ·g -1 The total pore volume of the waste plastic-derived porous carrier is 1.25-1.45 mL g -1 The BJH pore volume of the waste plastic derived porous carrier is 0.85-1.15 cm 3 / g, the HK method micropore volume of the waste plastic derived porous carrier is 0.44~0.5cm 3 / g, the BJH average pore diameter (4V / A) of the waste plastic derived porous carrier is 10-20nm.

10. Use of the waste plastics-derived porous carrier according to claim 9 in the preparation of a solid amine adsorbent.

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