A multifunctional catalyst, a method of making the same, and methods of using the same

Abstract

The present application discloses a multifunctional catalyst, a manufacturing method thereof and a method of using the same. The multifunctional catalyst is suitable for recycling polyester fabrics. The multifunctional catalyst comprises a carrier and a first functional ionic liquid and a second functional ionic liquid grafted on the carrier. The carrier is an inorganic composite powder material and is composed of the following chemical components: C:Na-Ni / Al2O3. In the process of recycling polyester fabrics, the multifunctional catalyst can simultaneously perform color removal and depolymerization on the polyester fabrics. The first functional ionic liquid is used to remove color from the polyester fabrics, and the second functional ionic liquid is used to depolymerize the polyester fabrics. In this way, the functions of depolymerization and color removal are provided, and the catalyst recycling is easy.

Description

Technical Field

[0001] This invention relates to a catalyst, and more particularly to a multifunctional catalyst for recycling polyester fabrics, its manufacturing method, and its use. Background Technology

[0002] Closed-loop chemical recycling technology for polyester (PET) has developed rapidly globally in recent years. Among these technologies, whether using solvent-assisted chemical degradation, biotechnology-assisted chemical degradation, or microwave-assisted chemical degradation, all have reached the pilot-scale production development stage. These chemical recycling technologies can be used to process various types of waste polyester materials, such as waste polyester bottle flakes or waste polyester textile fabrics.

[0003] For the recycling of waste polyester textiles, most existing chemical recycling technologies require the depolymerization and decolorization of waste polyester textiles to be carried out in separate processes, and there is also the problem that the catalyst is not easy to recover, resulting in excessively high recycling costs.

[0004] Therefore, the inventor felt that the above-mentioned defects could be improved, so he devoted himself to research and applied scientific principles, and finally proposed an invention that is reasonably designed and effectively improves the above-mentioned defects. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an environmentally friendly multifunctional catalyst for recycling polyester fabrics, its manufacturing method and its usage method, in order to address the shortcomings of the prior art.

[0006] To address the aforementioned technical problems, one technical solution adopted by this invention is to provide a multifunctional catalyst suitable for recycling polyester fabrics. The multifunctional catalyst comprises: a support; wherein the support is an inorganic composite powder material composed of a chemical composition having the following formula: C: Na-Ni / Al2O3; a first functional ionic liquid grafted onto the support; and a second functional ionic liquid grafted onto the support. During the recycling of polyester fabrics, the multifunctional catalyst can simultaneously decolorize and depolymerize the polyester fabrics, wherein the first functional ionic liquid is used to decolorize the polyester fabrics, and the second functional ionic liquid is used to depolymerize the polyester fabrics.

[0007] Preferably, the inorganic composite powder material is composed of a sodium-nickel composite alumina and a carbon-adsorbing material; wherein the inorganic composite powder material adsorbs carbon at its nickel atom ends; wherein the inorganic composite powder material is configured to decolorize the polyester fabric by means of the carbon component adsorbed at its nickel atom ends.

[0008] Preferably, the first functional ionic liquid is an imidazole ionic liquid, and is selected from at least one of the material group consisting of [C4mim][PF6], [C6mim][PF6], [C6mim][BF4], and [C8mim][PF6].

[0009] Preferably, the second functional ionic liquid is a salt composed of a cation and an anion; wherein the cation is selected from at least one of the group consisting of imidazole cations, pyridine cations, quaternary phosphine cations, and quaternary ammonium cations, and the anion is selected from: CI - ,Br - I - A1C14 - AlBr4 - A1I4 - CF3COO - CH3COO - CF3SO3 - SCN - (CF3SO2)2N - (CF3SO2) - 3C - C6H4(OH)(COO) - ), which is at least one of the material groups.

[0010] Preferably, the imidazole cation has the chemical structure of formula (1).

[0011]

[0012] The pyridine cation has the chemical structure of the following formula (2).

[0013]

[0014] The quaternary phosphine cation has the chemical structure of the following formula (3).

[0015]

[0016] The quaternary ammonium cation has the chemical structure of formula (4).

[0017]

[0018] Among them, R1, R2, R3, R4, and R5 are independent alkane groups, haloalkanes, hydroxyl groups, aromatic groups, or heterocyclic hydrocarbon groups.

[0019] Preferably, the total weight of the inorganic composite powder material is 100 wt%, and the carbon content is between 10 wt% and 15 wt%.

[0020] Preferably, the grafting ratio of the first functional ionic liquid to the second functional ionic liquid onto the carrier is between 5% and 40%.

[0021] Preferably, the grafting ratio of the first functional ionic liquid to the second functional ionic liquid onto the carrier is between 5% and 25%.

[0022] Preferably, the weight of the first functional ionic liquid with decolorization function is between 2 and 10 times the weight of the second functional ionic liquid with depolymerization function.

[0023] To address the aforementioned technical problems, another technical solution adopted by the present invention is to provide a method for manufacturing a multifunctional catalyst, comprising: providing a first inorganic composite powder material, which is composed of Na-Ni / Al2O3 with the following chemical composition; performing a reduction operation, comprising: using a fixed-bed reactor, under a reaction condition, introducing carbon dioxide gas into the first inorganic composite powder material to reduce the carbon dioxide gas into carbon components, which are adsorbed onto the nickel atom ends of the first inorganic composite powder material; performing a sintering operation, comprising: under a sintering condition, rearranging the lattice of the first inorganic composite powder material with the carbon components adsorbed onto the nickel atom ends to obtain a second inorganic composite powder material, which is composed of C:Na-Ni / Al2O3 with the following chemical composition; and performing a grafting operation, comprising: reacting a first functional ionic liquid and a second functional ionic liquid with a siloxane coupling agent respectively, and grafting them onto the second inorganic composite powder material through the siloxane coupling agent to obtain a multifunctional catalyst.

[0024] Preferably, the first functional ionic liquid is an imidazole ionic liquid, and is selected from at least one of the material group consisting of [C4mim][PF6], [C6mim][PF6], [C6mim][BF4], and [C8mim][PF6].

[0025] Preferably, the second functional ionic liquid is a salt composed of a cation and an anion; wherein the cation is selected from at least one of the group consisting of imidazole cations, pyridine cations, quaternary phosphine cations, and quaternary ammonium cations, and the anion is selected from: CI - ,Br - I - A1C14 - AlBr4 - A1I4 - CF3COO - CH3COO - CF3SO3 - SCN - (CF3SO2)2N - (CF3SO2) - 3C - C6H4(OH)(COO) - ), which is at least one of the material groups.

[0026] To address the aforementioned technical problems, another technical solution adopted by the present invention is to provide a method for using a multifunctional catalyst, comprising: providing a polyester fabric, which is a dyed polyester fabric; providing a multifunctional catalyst, which includes a support and a first functional ionic liquid and a second functional ionic liquid grafted onto the support; wherein the support is an inorganic composite powder material composed of a chemical composition having the following formula: C: Na-Ni / Al2O3; mixing the polyester fabric, the multifunctional catalyst, and a chemical depolymerization solution, such that the first functional ionic liquid decolorizes the polyester fabric and the second functional ionic liquid depolymerizes the polyester fabric, thereby obtaining a depolymerized product after decolorization and depolymerization; wherein the depolymerization product includes polyethylene terephthalate; and separating the multifunctional catalyst from the polyethylene terephthalate.

[0027] One of the beneficial effects of this invention is that the multifunctional catalyst, its manufacturing method, and its usage method provided by this invention can simultaneously possess depolymerization and decolorization functions through the special material selection of the carrier and the grafting of a first functional ionic liquid and a second functional ionic liquid onto the carrier, and also has the advantage of easy recycling. The special material design of the multifunctional catalyst of this invention enables the decolorization and depolymerization of polyester fabrics in the same process flow, and solves the problem of excessively high recycling costs in existing chemical recycling technologies.

[0028] Furthermore, the inorganic composite powder material can also remove dyes from polyester fabrics by adsorbing carbon at the ends of its nickel atoms, thereby improving the color removal efficiency of the multifunctional catalyst.

[0029] In addition, since the inorganic composite powder material is composed of sodium-nickel composite alumina, the multifunctional catalyst can be recovered by magnetic materials (such as magnets) or by filtration.

[0030] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the chemical structure of the multifunctional catalyst according to an embodiment of the present invention.

[0032] Figure 2 This is a flowchart illustrating the manufacturing method of the multifunctional catalyst according to an embodiment of the present invention.

[0033] Figure 3 This is a flowchart illustrating the method of using the multifunctional catalyst according to an embodiment of the present invention. Detailed Implementation

[0034] The following specific embodiments illustrate the implementation methods disclosed in this invention. Those skilled in the art can understand the advantages and effects of this invention from the content disclosed in this specification. This invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of this invention. Furthermore, the accompanying drawings of this invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated beforehand. The following embodiments will further describe the relevant technical content of this invention in detail, but the disclosed content is not intended to limit the scope of protection of this invention.

[0035] It should be understood that while terms such as "first," "second," and "third" may be used in this document to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. Furthermore, the term "or" as used herein should, as appropriate, include any combination of one or more of the related listed items.

[0036] [Multifunctional Catalyst]

[0037] This invention provides a multifunctional catalyst suitable for recycling polyester fabrics. During the recycling process, the multifunctional catalyst can decolorize and depolymerize the polyester fabric in the same process, and the catalyst can be easily recovered, thereby reducing the cost of the recycling operation. The polyester specifically refers to polyethylene terephthalate (PET).

[0038] like Figure 1 As shown, the multifunctional catalyst 100 comprises: a support S and a first functional ionic liquid IL-1 and a second functional ionic liquid IL-2 grafted onto the support S.

[0039] The carrier S is an inorganic composite powder material, and the inorganic composite powder material is composed of a chemical composition having the following formula: C: Na-Ni / Al2O3. Alternatively, the inorganic composite powder material is composed of a composite sodium-nickel alumina (Na-Ni / Al2O3) and a carbon-adsorbing material. Specifically, the inorganic composite powder material adsorbs carbon (C:) at the nickel atom ends.

[0040] The first functional ionic liquid IL-1 and the second functional ionic liquid IL-2 are grafted onto the carrier S via chemical covalent bonding. Specifically, the first functional ionic liquid IL-1 is used to decolorize the polyester fabric during the recycling process, and the second functional ionic liquid IL-2 is used to depolymerize the polyester fabric during the recycling process. In other words, the first functional ionic liquid IL-1 and the second functional ionic liquid IL-2 can perform decolorization and depolymerization of the polyester fabric in the same process.

[0041] It is worth mentioning that the inorganic composite powder material can also further remove dyes from polyester fabrics by adsorbing carbon at the ends of its nickel atoms, thereby improving the color removal efficiency of the multifunctional catalyst.

[0042] Furthermore, since the inorganic composite powder material is composed of composite sodium-nickel alumina (Na-Ni / Al2O3), the multifunctional catalyst 100 can be recovered by magnetic materials (such as magnets) or by filtration.

[0043] Furthermore, the first functional ionic liquid IL-1 with decolorization function can be, for example, an imidazole ionic liquid.

[0044] In various embodiments of the present invention, the first functional ionic liquid is selected from at least one of the group consisting of [C4mim][PF6], [C6mim][PF6], [C6mim][BF4], and [C8mim][PF6]. The first functional ionic liquid can be used to remove anionic dyes, such as methyl orange, eosin yellow, or orange G solution, and exhibits good decolorization efficiency for these anionic dyes in an aqueous environment with a suitable pH. Specifically, [PF6] or [BF4] in the aforementioned ionic liquid has the ability to remove dyes.

[0045] Furthermore, the second functional ionic liquid IL-2 with depolymerization function can, for example, be a salt composed of a cation and an anion. The cation of the second functional ionic liquid IL-2 is selected from at least one of the group consisting of imidazolium cations, pyridium cations, quaternary phosphonium ions, and quaternary ammonium cations. These cations have depolymerization capabilities against polyesters.

[0046] Table 1 shows the chemical structures of the cations of the second functional ionic liquid. Among them, the imidazole cation has the chemical structure of formula (1), the pyridine cation has the chemical structure of formula (2), the quaternary phosphine cation has the chemical structure of formula (3), and the quaternary ammonium cation has the chemical structure of formula (4).

[0047] [Table 1]

[0048]

[0049]

[0050] In the above chemical structure, the substituents R1, R2, R3, R4, and R5 are independent (identical or different) alkane groups, halogenated hydroxyl groups, hydroxyl groups, aromatic groups, or heterocyclic hydroxyl groups. The number of carbon atoms in the aliphatic chain organic substituents of the above substituents R1, R2, R3, R4, and R5 is between 1 and 14.

[0051] The anions of the second functional ionic liquid IL-2 are selected from: CI-, Br-, I-, AlCl4-, AlBr4-, AlI4-, CF3COO-, CH3COO-, CF3SO3-, SCN-, (CF3SO2)2N-, (CF3SO4)2N-, and (CF3SO4)2N-. 2- It is at least one of the material groups consisting of 3C- and C6H4(OH)(COO-).

[0052] In some embodiments of the present invention, based on the total weight of the inorganic composite powder material (C: Na-Ni / Al2O3) being 100 wt%, the carbon content being between 10 wt% and 15 wt% of the total weight, thereby enabling the carbon adsorbed at the nickel atom ends to give the inorganic composite powder material a decolorizing effect.

[0053] If the carbon content is too high, the carbon will become saturated and unable to adsorb onto the nickel atom ends. Conversely, if the carbon content is too low, the carbon concentration will be too low to provide sufficient decolorization.

[0054] In some embodiments of the present invention, the weight of the support S (C: Na-Ni / Al2O3) of the multifunctional catalyst 100 is defined as a first weight. The total weight of the first functional ionic liquid IL-1 and the second functional ionic liquid IL-2 of the multifunctional catalyst 100 is defined as a second weight. Further, the weight ratio between the first weight and the second weight is between 1:0.05 and 1:0.40, preferably between 1:0.05 and 1:0.25. That is, the total weight of the first functional ionic liquid IL-1 and the second functional ionic liquid IL-2 is between 5% and 40% (preferably 5% to 25%) of the weight of the support S. In other words, the grafting ratio of the first functional ionic liquid IL-1 and the second functional ionic liquid IL-2 onto the support S is 5% to 40% (preferably 5% to 25%).

[0055] In some embodiments of the present invention, the weight ratio between the first functional ionic liquid IL-1 with decolorizing function and the second functional ionic liquid IL-2 with depolymerization function is between 2:1 and 10:1, and preferably 4:1. That is, the weight of the first functional ionic liquid IL-1 with decolorizing function is between 2 and 10 times, and preferably 4 times, the weight of the second functional ionic liquid IL-2 with depolymerization function, but the present invention is not limited thereto.

[0056] According to the above configuration, the multifunctional catalyst 100 of this embodiment of the invention can simultaneously possess depolymerization and decolorization functions through the special material selection of the support S and the grafting of the first functional ionic liquid IL-1 and the second functional ionic liquid IL-2 onto the support S, and also has the advantage of easy recycling. The special material design of the multifunctional catalyst 100 of this embodiment of the invention enables the decolorization and depolymerization of polyester fabrics in the same process, and solves the problem of excessively high recycling costs in existing chemical recycling technologies.

[0057] [Manufacturing Method of Multifunctional Catalysts]

[0058] The above describes the material characteristics of the multifunctional catalyst according to the embodiments of the present invention. The following describes the manufacturing method of the multifunctional catalyst according to the embodiments of the present invention.

[0059] like Figure 2 As shown, the manufacturing method of the multifunctional catalyst includes steps S110, S120, S130, and S140. It should be noted that the order of the steps and the actual operation method described in this embodiment can be adjusted according to requirements, and the present invention is not limited to the embodiments described herein.

[0060] Step S110 includes: providing a first inorganic composite powder material, which is composed of the following chemical composition: Na-Ni / Al2O3.

[0061] Step S120 includes performing a reduction operation, which includes: using a fixed-bed reactor, under reaction conditions of a reaction temperature and a reaction time, introducing carbon dioxide gas into a first inorganic composite powder material to reduce the carbon dioxide gas into carbon components, and causing the carbon components to be adsorbed at the nickel atom ends of the first inorganic composite powder material (Na-Ni / Al2O3). The reaction temperature is between 400°C and 800°C (preferably between 400°C and 600°C), and the reaction time is between 2 hours and 72 hours (preferably between 12 hours and 36 hours).

[0062] Step S130 includes performing a sintering operation, which includes: lattice rearrangement of a first inorganic composite powder material with carbon adsorbed at the nickel atom ends under sintering conditions of a sintering temperature and a sintering time to obtain a second inorganic composite powder material, which is composed of the chemical composition C: Na-Ni / Al2O3. The sintering temperature is between 500°C and 800°C (preferably between 500°C and 700°C), and the sintering time is between 1 hour and 2 hours (preferably between 12 and 48 hours).

[0063] Step S140 includes performing a grafting operation, which includes reacting a first functional ionic liquid and a second functional ionic liquid with a siloxane coupling agent respectively, and grafting the first functional ionic liquid and the second functional ionic liquid onto the second inorganic composite powder material through the siloxane coupling agent to obtain the multifunctional catalyst.

[0064] [How to use a multi-functional catalyst]

[0065] The above describes the manufacturing method of the multifunctional catalyst according to the embodiments of the present invention. The following describes the usage method of the multifunctional catalyst according to the embodiments of the present invention.

[0066] like Figure 3 As shown, the method of using the multifunctional catalyst includes steps S210, S220, S230, and S240. It should be noted that the order of the steps and the actual operation method described in this embodiment can be adjusted according to requirements, and the present invention is not limited to the embodiments described herein.

[0067] Step S210 includes: providing a polyester fabric, wherein the polyester fabric is a dyed polyester fabric.

[0068] Step S220 includes: providing a multifunctional catalyst, wherein the multifunctional catalyst includes a support and a first functional ionic liquid and a second functional ionic liquid grafted onto the support.

[0069] The carrier is an inorganic composite powder material, and the inorganic composite powder material is composed of a chemical composition having the following formula: C: Na-Ni / Al2O3. Alternatively, the inorganic composite powder material is composed of a composite sodium-nickel alumina (Na-Ni / Al2O3) and a carbon-adsorbing material. Specifically, the inorganic composite powder material adsorbs carbon (C:) at the nickel atom ends.

[0070] The first functional ionic liquid may be, for example, an imidazole ionic liquid. The first functional ionic liquid is selected from at least one of the group of materials consisting of [C4mim][PF6], [C6mim][PF6], [C6mim][BF4], and [C8mim][PF6].

[0071] The cation of the second functional ionic liquid is selected from at least one of the following groups of materials: imidazolium cation, pyridium cation, quaternary phosphonium cation, and quaternary ammonium cation. The anion of the second functional ionic liquid is selected from at least one of the following groups of materials: Cl-, Br-, I-, AlCl4-, AlBr4-, AlI4-, CF3COO-, CH3COO-, CF3SO3-, SCN-, (CF3SO2)2N-, (CF3SO2-)3C-, and C6H4(OH)(COO-).

[0072] Step S230 includes: mixing the dyed polyester fabric, a multifunctional catalyst, and a chemical depolymerization solution in a predetermined weight ratio, and heating and stirring the mixture so that the first functional ionic liquid can decolorize the polyester fabric and the second functional ionic liquid can depolymerize the polyester fabric, thereby obtaining a depolymerized product that has undergone decolorization and depolymerization. In other words, the first and second functional ionic liquids can decolorize and depolymerize the polyester fabric in the same process.

[0073] The dyed polyester fabric, the multifunctional catalyst, and the chemical depolymerization solution are mixed in a predetermined weight ratio between 10~30:0.05~1:60~90, but the present invention is not limited thereto.

[0074] The depolymerization product comprises: polyethylene terephthalate (BHET), the multifunctional catalyst, and the chemical depolymerization solution. The polyethylene terephthalate is formed by the degradation of polyester fabric. Furthermore, the chemical depolymerization solution may be, for example, ethylene glycol (EG), but the invention is not limited thereto.

[0075] It is worth mentioning that the inorganic composite powder material can also further remove dyes from polyester fabrics by adsorbing carbon at the ends of its nickel atoms, thereby improving the color removal efficiency of the multifunctional catalyst.

[0076] Step S240 includes performing a catalyst recovery operation to separate the multifunctional catalyst from polyethylene terephthalate (BHET) and the chemical depolymerization solution. The catalyst recovery operation can be achieved, for example, by magnetically attracting the multifunctional catalyst using a magnetic material (e.g., a magnet), but the invention is not limited thereto. The catalyst recovery operation can also be performed, for example, by filtration or centrifugation to recover the multifunctional catalyst.

[0077] According to the above configuration, the depolymerization product has a degradation efficiency of not less than 90% (the efficiency of polyester fabric degradation to form BHET) as tested by GPC. The polyethylene terephthalate (BHET) has an L value of not less than 90, an a value between -1 and 1, and a b value between -5 and 5.

[0078] [Experimental Data and Test Results]

[0079] The present invention will now be described in detail with reference to Examples 1 to 4. However, these examples are provided only to help understand the present invention, and the scope of the present invention is not limited to these examples.

[0080] The preparation steps of Example 1 include: providing a dyed light-colored polyester fabric and placing it in a chemical depolymerization solution (ethylene glycol); then placing a multifunctional catalyst into the chemical depolymerization solution to decolorize and depolymerize the dyed light-colored polyester fabric. The multifunctional catalyst comprises: a support and a first functional ionic liquid and a second functional ionic liquid grafted onto the support.

[0081] The aforementioned support is composed of C:Na-Ni / Al2O3. The first functional ionic liquid in Example 1 is [C4mim][PF6], and the cation in the second functional ionic liquid is an imidazole cation, while the anion is Cl-. The grafting ratio of the first and second functional ionic liquids onto the support is 20.1% (by weight). Furthermore, the weight ratio between the first functional ionic liquid (decolorizing) and the second functional ionic liquid (depolymerizing) is 4:1. The added weight of the multifunctional catalyst is 2% of the weight of the polyester fabric. Additionally, the reaction time for depolymerization and decolorization is 2 hours. It should be noted that although only one material combination of the first and second functional ionic liquids is described in Examples 1-4, the present invention is not limited thereto. To those skilled in the art, it is understandable that the other materials with similar properties listed in the specification for the first and second functional ionic liquids, although not tested, should be able to infer that they have similar technical effects, namely: the first ionic liquid has a decolorization function, while the second ionic liquid has a depolymerization function.

[0082] After testing, the depolymerization efficiency of Example 1 was 93%, meaning that 93% of the polyester fabric was degraded into polyethylene terephthalate (BHET), indicating that the preparation conditions of Example 1 have good depolymerization efficiency. Regarding color removal, the polyethylene terephthalate (BHET) of Example 1 had an L value of 80, an a value of 0.16, and a b value of 4.46, indicating that the preparation conditions of Example 1 can produce polyethylene terephthalate (BHET) with good hue.

[0083] The depolymerization efficiency mentioned above was determined through GPC analysis. The depolymerization efficiency of polyester is calculated as (initial mass of polyester – mass of undepolymerized polyester) / initial mass of polyester. 100%. The Lab color space is a color-opposite space, and Lab values ​​are measured using a spectrometer.

[0084] The preparation conditions for Example 2 were largely the same as those for Example 1, except that the ionic liquid grafting ratio in Example 2 was 14.2%. The depolymerization efficiency of Example 2 was 92%, and BHET had an L value of 83, an a value of -0.65, and a b value of 3.9. The preparation conditions for Example 3 were largely the same as those for Example 1, except that the ionic liquid grafting ratio in Example 3 was 9.0%. The depolymerization efficiency of Example 3 was 91%, and BHET had an L value of 85, an a value of -0.73, and a b value of 3.1. The preparation conditions for Example 4 were largely the same as those for Example 1, except that the ionic liquid grafting ratio in Example 4 was 5.0%. The depolymerization efficiency of Example 4 was 91%, and BHET had an L value of 86, an a value of 0.07, and a b value of 1.8. Overall, as shown in Table 2, the preparation conditions of Examples 1 to 4 all have good depolymerization efficiency (greater than 90%) and good hue (L>80, a = -1~1, b= -5~5).

[0085] [Table 2]

[0086]

[0087] Next, as shown in Table 3, a multifunctional catalyst with an ionic liquid grafting ratio of 14.2% (Example 2) was subjected to twenty catalyst depolymerization and recovery cycles. The reaction time for both depolymerization and decolorization was 2 hours. Under the above conditions, each recovered catalyst provided a depolymerization efficiency of not less than 90%, and the decolorization effect of BHET met the following levels: L>80, a= -1~1, b= -5~5.

[0088] [Table 3]

[0089]

[0090] [Beneficial Effects of the Examples]

[0091] One of the beneficial effects of this invention is that the multifunctional catalyst, its manufacturing method, and its usage method provided by this invention can simultaneously possess depolymerization and decolorization functions through the special material selection of the carrier and the grafting of a first functional ionic liquid and a second functional ionic liquid onto the carrier, and also has the advantage of easy recycling. The special material design of the multifunctional catalyst of this invention enables the decolorization and depolymerization of polyester fabrics in the same process flow, and solves the problem of excessively high recycling costs in existing chemical recycling technologies.

[0092] Furthermore, the inorganic composite powder material can also remove dyes from polyester fabrics by adsorbing carbon at the ends of its nickel atoms, thereby improving the color removal efficiency of the multifunctional catalyst.

[0093] In addition, since the inorganic composite powder material is composed of sodium-nickel composite alumina, the multifunctional catalyst can be recovered by magnetic materials (such as magnets) or by filtration.

[0094] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention specification and drawings are included in the scope of the patent application of the present invention.

Claims

1. A multifunctional catalyst suitable for recycling polyester fabrics, characterized in that, The multifunctional catalyst includes: A carrier; wherein the carrier is an inorganic composite powder material, the inorganic composite powder material being composed of sodium-nickel composite alumina and a carbon-adsorbing material; A first functional ionic liquid grafted onto the support; the first functional ionic liquid is an imidazole ionic liquid and is selected from at least one of the material group consisting of [C4mim][PF6], [C6mim][PF6], [C6mim][BF4], and [C8mim][PF6]; and A second functional ionic liquid grafted onto the carrier; the second functional ionic liquid is a salt composed of a cation and an anion; wherein the cation is selected from at least one of the group consisting of imidazole cations, pyridine cations, quaternary phosphine cations, and quaternary ammonium cations, and the anion is selected from: CI - ,Br - I - A1C14 - AlBr4 - A1I4 - CF3COO - CH3COO - CF3SO3 - SCN - (CF3SO2)2N - (CF3SO2) - 3C - C6H4(OH)(COO) - ), and at least one of the material groups formed by them; In the process of recycling polyester fabric, the multifunctional catalyst can simultaneously decolorize and depolymerize the polyester fabric. The first functional ionic liquid is used to decolorize the polyester fabric, and the second functional ionic liquid is used to depolymerize the polyester fabric. The imidazole cation has the chemical structure of formula (1) below. The pyridine cation has the chemical structure of the following formula (2), The quaternary phosphine cation has the chemical structure of the following formula (3), Furthermore, the quaternary ammonium cation has the chemical structure of formula (4) below. Among them, R1, R2, R3, R4, and R5 are independent alkane groups, haloalkanes, hydroxyl groups, aromatic groups, or heterocyclic hydrocarbon groups.

2. The multifunctional catalyst according to claim 1, characterized in that, The inorganic composite powder material adsorbs carbon at its nickel atom ends; wherein, the inorganic composite powder material is configured to remove color from the polyester fabric by adsorbing carbon at its nickel atom ends.

3. The multifunctional catalyst according to claim 1, characterized in that, The total weight of the inorganic composite powder material is 100 wt%, and the carbon content is between 10 wt% and 15 wt%.

4. The multifunctional catalyst according to claim 1, characterized in that, The grafting ratio of the first functional ionic liquid to the second functional ionic liquid onto the carrier is between 5% and 40%.

5. The multifunctional catalyst according to claim 4, characterized in that, The grafting ratio of the first functional ionic liquid to the second functional ionic liquid onto the carrier is between 5% and 25%.

6. The multifunctional catalyst according to claim 4, characterized in that, The weight of the first functional ionic liquid with decolorization function is between 2 and 10 times the weight of the second functional ionic liquid with depolymerization function.

7. A method for manufacturing a multifunctional catalyst, characterized in that, The method for manufacturing the multifunctional catalyst includes: A first inorganic composite powder material is provided, wherein the first inorganic composite powder material is composed of sodium-nickel composite aluminum oxide; A reduction operation is performed, comprising: using a fixed-bed reactor, under certain reaction conditions, introducing carbon dioxide gas into the first inorganic composite powder material to reduce the carbon dioxide gas into carbon components, which are then adsorbed onto the nickel atom ends of the first inorganic composite powder material; A sintering operation is performed, comprising: lattice rearrangement of the first inorganic composite powder material, in which the nickel atom ends are adsorbed with the carbon component, under sintering conditions to obtain a second inorganic composite powder material, wherein the second inorganic composite powder material is composed of a sodium-nickel composite alumina and a carbon-adsorbed material. A grafting operation is performed, comprising: reacting a first functional ionic liquid and a second functional ionic liquid with a siloxane coupling agent respectively, and grafting them onto a second inorganic composite powder material through the siloxane coupling agent to obtain a multifunctional catalyst. Wherein, the first functional ionic liquid is an imidazole ionic liquid, and is selected from at least one of the material group consisting of: [C4mim][PF6], [C6mim][PF6], [C6mim][BF4] and [C8mim][PF6]. The second functional ionic liquid is a salt composed of a cation and an anion; wherein the cation is selected from at least one of the group consisting of imidazole cations, pyridine cations, quaternary phosphine cations, and quaternary ammonium cations, and the anion is selected from: CI - ,Br - I - A1C14 - AlBr4 - A1I4 - CF3COO - CH3COO - CF3SO3 - SCN - (CF3SO2)2N - (CF3SO2) - 3C - C6H4(OH)(COO) - ), and at least one of the material groups formed by them; The imidazole cation has the chemical structure of formula (1) below. The pyridine cation has the chemical structure of the following formula (2), The quaternary phosphine cation has the chemical structure of the following formula (3), Furthermore, the quaternary ammonium cation has the chemical structure of formula (4) below. Among them, R1, R2, R3, R4, and R5 are independent alkane groups, haloalkanes, hydroxyl groups, aromatic groups, or heterocyclic hydrocarbon groups.

8. A method of using a multifunctional catalyst, characterized in that, The method of using the multifunctional catalyst includes: A polyester fabric is provided, which is a dyed polyester fabric; A multifunctional catalyst is provided, comprising a support and a first functional ionic liquid and a second functional ionic liquid grafted onto the support; wherein the support is an inorganic composite powder material, the inorganic composite powder material being composed of a sodium-nickel composite alumina and a carbon-adsorbing material; Wherein, the first functional ionic liquid is an imidazole ionic liquid, and is selected from at least one of the material group consisting of: [C4mim][PF6], [C6mim][PF6], [C6mim][BF4] and [C8mim][PF6]. The second functional ionic liquid is a salt composed of a cation and an anion; wherein the cation is selected from at least one of the group consisting of imidazole cations, pyridine cations, quaternary phosphine cations, and quaternary ammonium cations, and the anion is selected from: CI - ,Br - I - A1C14 - AlBr4 - A1I4 - CF3COO - CH3COO - CF3SO3 - SCN - (CF3SO2)2N - (CF3SO2) - 3C - C6H4(OH)(COO) - ), and at least one of the material groups formed by them; The imidazole cation has the chemical structure of formula (1) below. The pyridine cation has the chemical structure of the following formula (2), The quaternary phosphine cation has the chemical structure of the following formula (3), Furthermore, the quaternary ammonium cation has the chemical structure of formula (4) below. Among them, R1, R2, R3, R4, and R5 are independent alkane groups, haloalkanes, hydroxyl groups, aromatic groups, or heterocyclic hydrocarbon groups; The polyester fabric, the multifunctional catalyst, and a chemical depolymerization solution are mixed to decolorize the polyester fabric with the first functional ionic liquid and depolymerize the polyester fabric with the second functional ionic liquid, thereby obtaining a depolymerization product after decolorization and depolymerization; wherein the depolymerization product comprises polyethylene terephthalate; and The multifunctional catalyst is separated from the ethylene terephthalate.

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