Dual-responsiveness eutectic solvent as well as preparation method and application thereof

Abstract

The invention provides a dual-responsiveness eutectic solvent as well as a preparation method and application thereof. The dual-responsiveness deep-eutectic solvent comprises hydrogen bond donors and hydrogen bond acceptors, wherein the hydrogen bond donors comprise a first hydrogen bond donor and a second hydrogen bond donor; the first hydrogen bond donor comprises a polyalcohol compound containing a light response group, and the second hydrogen bond donor comprises a temperature-sensitive compound. The dual-responsiveness deep-eutectic solvent provided by the invention realizes one-step high-selectivity leaching and separation of various valuable metals from the positive electrode active material of the waste lithium ion battery, so that transition metal elements are separated out in a precipitation form, the lithium element is leached in the solution, and the subsequent extra complicated separation process is avoided.

Description

Technical Field

[0001] This invention belongs to the field of battery material recycling technology, specifically relating to a dual-responsive eutectic solvent, its preparation method, and its application. Background Technology

[0002] In recent years, with the rapid development of new energy vehicles, the output of used lithium-ion batteries has increased dramatically. The cathode material of lithium-ion batteries accounts for 45% of the total battery cost, and its active materials mainly include lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4), and lithium nickel cobalt manganese oxide (LiNiO2). x Co y Mn 1-x-y Materials containing valuable metal elements such as Li, Ni, Co, and Mn (e.g., O2) can help alleviate resource shortages by recycling used lithium-ion batteries.

[0003] The current methods for recycling spent lithium-ion batteries, including pyrometallurgy, hydrometallurgy, and remediation, all have their shortcomings, necessitating a more environmentally friendly and efficient approach. Desiccant (DES) exhibits unique advantages in spent lithium-ion battery recycling due to its thermal stability, ease of synthesis, and low toxicity. However, DES suffers from technical limitations, such as high viscosity restricting mass transfer rates leading to slow reaction rates, complex metal ion recovery processes after leaching, limited recyclability, and even non-recyclability of some DES components. These limitations restrict its application in industrial production.

[0004] Therefore, there is an urgent need in this field to develop a eutectic solvent system that can more efficiently recover valuable metals from the cathode, thereby solving the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a dual-responsive eutectic solvent, its preparation method, and its application. This solvent enables a one-step highly selective leaching separation of multiple valuable metals from the positive electrode active material of spent lithium-ion batteries, allowing transition metal elements to precipitate out while lithium elements leach out in the solution, thus avoiding subsequent complex separation processes.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a dual-responsive eutectic solvent, the dual-responsive eutectic solvent comprising a hydrogen bond donor and a hydrogen bond acceptor, the hydrogen bond donor comprising a first hydrogen bond donor and a second hydrogen bond donor;

[0008] The first hydrogen bond donor includes a polyol compound containing a photoresponsive group, and the second hydrogen bond donor includes a thermosensitive compound.

[0009] This invention provides a dual-responsive eutectic solvent that can modulate the hydrogen bond network through temperature or light, thereby achieving controllable viscosity and two-phase separation. Furthermore, the dual-responsive eutectic solvent provided by this invention can improve reaction kinetics, reduce leaching time, lower leaching temperature, and increase overall leaching efficiency.

[0010] Specifically, the advantages of the eutectic solvent provided by this invention are mainly reflected in its photoresponse or temperature response characteristics. The photoresponse characteristic allows it to generate localized heating or chemical activation under irradiation with light of a specific wavelength, thereby reducing the bonding energy on the surface of metal oxides, making it easier for metal ions to be complexed and migrate into the solution. The temperature response characteristic changes viscosity or polarity after heating to a set threshold, similarly promoting the dissociation and dissolution of metal ions. Both of these response mechanisms can achieve efficient extraction of key metals such as lithium, nickel, cobalt, and manganese from positive electrode active materials, significantly improving recovery rates and reducing energy consumption and chemical reagent usage, thus achieving greener and more economical resource recycling.

[0011] Preferably, the photoresponsive group includes o-nitrophenyl.

[0012] Preferably, the polypolyol compound containing photoresponsive groups includes o-nitrophenyl-polyethylene glycol-400.

[0013] Preferably, the thermosensitive compound includes at least one of p-toluenesulfonamide, N-ethyl-p-toluenesulfonamide, or N-methyl-p-toluenesulfonamide.

[0014] It should be noted that the thermosensitive compounds described in this invention refer to combinations of functional groups in their molecular structure that can alter intermolecular interactions (such as hydrogen bonds and hydrophobic interactions) with temperature changes. For example, the thermosensitive compounds may contain strong hydrogen-bonding groups such as sulfonamide groups, and simultaneously possess certain hydrophobic structural units (such as aromatic rings, alkyl groups, etc.). This balance of hydrophilic and hydrophobic structures causes significant changes in solubility, conformation, or aggregation state at specific temperature thresholds, thereby regulating the macroscopic properties of eutectic solvents, such as viscosity or phase.

[0015] Preferably, with the total molar amount of the hydrogen bond donor being 100%, the molar percentage of the first hydrogen bond donor is 30% to 70%, for example, it can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] Preferably, with the total molar amount of the hydrogen bond donor being 100%, the molar percentage of the second hydrogen bond donor is 30% to 70%, for example, it can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] In this invention, by controlling the structure and content relationship of two hydrogen bond donors, a variety of hydrogen bond donors with different structures are introduced, enabling the formation of a richer and more tunable hydrogen bond network on the surface of the metal oxide cathode material. These hydrogen bonds significantly enhance the interaction between metal ions (such as lithium, cobalt, nickel, and manganese) and solvent molecules, resulting in higher coordination stability of metal ions during dissolution and reducing migration resistance in the solvent. Simultaneously, the tunability of the hydrogen bond network facilitates higher selective capture and enrichment of metal ions in subsequent leaching steps, thereby improving metal recovery and reducing residual metal loss.

[0018] Preferably, the hydrogen bond acceptor includes choline chloride.

[0019] Preferably, the dual-responsive eutectic solvent further includes functional additives.

[0020] Preferably, the functional additive includes triethanolamine.

[0021] Preferably, based on the total mass of the dual-responsive eutectic solvent as 100%, the mass percentage of the functional additive is 5% to 15%, for example, it can be 5%, 8%, 10%, 12% or 15%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0022] Preferably, the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is (2~6):1, for example, it can be 2:1, 3:1, 4:1, 5:1 or 6:1, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable. This invention improves the leaching efficiency of valuable metals by controlling the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor. Too high or too low a molar ratio will negatively impact leaching.

[0023] In this invention, by adjusting the molar ratio of hydrogen bond donors to hydrogen bond acceptors to a reasonable range, the reducing properties and acidity of the formed eutectic solvent can be precisely controlled, enabling metal ions to form more soluble metal-coordination complexes in the solvent. This significantly improves the recovery rate of valuable metals such as lithium, cobalt, nickel, and manganese, while reducing leaching temperature and energy consumption.

[0024] In a second aspect, the present invention provides a method for preparing a dual-responsive eutectic solvent as described in the first aspect, the method comprising the following steps:

[0025] The first hydrogen bond donor, the second hydrogen bond donor, and the hydrogen bond acceptor are heated for the first time to obtain the dual-responsive eutectic solvent, wherein the first hydrogen bond donor includes a polyol compound containing a photoresponsive group, and the second hydrogen bond donor includes a thermosensitive compound.

[0026] This invention improves the efficiency of metal recycling by rationally designing and controlling the leaching process, thereby achieving a more sustainable and environmentally friendly treatment and recycling of waste lithium-ion batteries.

[0027] Preferably, the temperature of the first heating is 60℃~80℃, and the heating time is 20min~50min.

[0028] Specifically, the temperature of the first heating can be, for example, 60℃, 65℃, 70℃, 75℃ or 80℃; the time of the first heating can be, for example, 20min, 30min, 40min or 50min, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] Thirdly, the present invention provides a method for recycling metal elements from waste positive electrode sheets, the method comprising the following steps:

[0030] Under light or secondary heating conditions, the waste positive electrode sheet to be recycled is reacted with the dual-responsive eutectic solvent as described in the first aspect to obtain a lithium-rich leachate and a chelate containing transition metal ions.

[0031] The eutectic solvent provided by this invention exhibits a stronger hydrogen bonding effect under light irradiation or secondary heating conditions, thereby improving the leaching efficiency of many valuable metals in the positive electrode active material.

[0032] Preferably, the illumination conditions are: illumination intensity of 10 mW / cm². 2 ~50mW / cm 2 For example, it can be 10mW / cm 2 20mW / cm 2 30mW / cm 2 40mW / cm 2 Or 50mW / cm 2 The term "etc." is not limited to the listed values; it also applies to other unlisted values ​​within the range.

[0033] Preferably, the temperature of the second heating is 60℃~90℃, and the time of the second heating is 2h~6h.

[0034] Specifically, the temperature of the second heating can be, for example, 60°C, 70°C, 80°C, or 90°C; the time of the second heating can be, for example, 2h, 4h, 5h, or 6h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the solid-liquid ratio of the waste positive electrode to be recycled to the dual-responsive eutectic solvent is 1:(70-90), for example, it can be 1:70, 1:72, 1:75, 1:78, 1:80, 1:82, 1:85, 1:88 or 1:90, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] In this invention, by adjusting the solid-liquid ratio of the waste positive electrode sheet to be recycled and the dual-responsive eutectic solvent, it is possible to ensure that the solvent fully penetrates and uniformly contacts the active material inside the positive electrode sheet, thereby promoting the dissolution rate of metal ions in the eutectic system.

[0037] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] This invention provides a dual-responsive eutectic solvent that can modulate the hydrogen bond network through temperature or light, thereby achieving controllable viscosity and two-phase separation. Furthermore, the dual-responsive eutectic solvent provided by this invention can improve reaction kinetics, reduce leaching time, lower leaching temperature, and increase overall leaching efficiency.

[0040] The advantages of the eutectic solvent provided by this invention are mainly reflected in its photoresponse or temperature response characteristics. The photoresponse characteristic allows it to generate localized heating or chemical activation under irradiation with light of a specific wavelength, thereby reducing the bonding energy on the surface of metal oxides, making it easier for metal ions to be complexed and migrate into the solution. The temperature response characteristic changes viscosity or polarity after heating to a set threshold, similarly promoting the dissociation and dissolution of metal ions. Both of these response mechanisms can achieve efficient extraction of key metals such as lithium, nickel, cobalt, and manganese from positive electrode active materials, significantly improving recovery rates and reducing energy consumption and chemical reagent usage, thus achieving greener and more economical resource recycling. Detailed Implementation

[0041] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0042] Example 1

[0043] This embodiment provides a dual-responsive eutectic solvent, which includes a first hydrogen bond donor, a second hydrogen bond donor, a choline chloride hydrogen bond acceptor, and a triethanolamine additive. The first hydrogen bond donor is o-nitrophenyl-polyethylene glycol-400, and the second hydrogen bond donor is p-toluenesulfonamide.

[0044] Of these, based on the total molar amount of all hydrogen bond donors as 100%, the molar percentage of o-nitrophenyl-polyethylene glycol-400 is 50%, and the molar percentage of p-toluenesulfonamide is 50%; the molar ratio of the combination of the first and second hydrogen bond donors to the hydrogen bond acceptor is 4:1; and based on the total mass of the dual-responsive eutectic solvent as 100%, the mass percentage of triethanolamine additive is 10%.

[0045] This embodiment also provides a method for preparing the above-mentioned dual-responsive eutectic solvent, the preparation method comprising the following steps:

[0046] The first hydrogen bond donor, the second hydrogen bond donor, the hydrogen bond acceptor, and the additive were heated at 70°C for 35 minutes according to the formulation to obtain the dual-responsive eutectic solvent.

[0047] Example 2

[0048] This embodiment provides a dual-responsive eutectic solvent, which includes a first hydrogen bond donor, a second hydrogen bond donor, a choline chloride hydrogen bond acceptor, and a triethanolamine additive. The first hydrogen bond donor is o-nitrophenyl-polyethylene glycol-400, and the second hydrogen bond donor is p-toluenesulfonamide.

[0049] Of these, based on the total molar amount of all hydrogen bond donors as 100%, the molar percentage of o-nitrophenyl-polyethylene glycol-400 is 70%, and the molar percentage of p-toluenesulfonamide is 30%; the molar ratio of the combination of the first and second hydrogen bond donors to the hydrogen bond acceptor is 2:1; and based on the total mass of the dual-responsive eutectic solvent as 100%, the mass percentage of triethanolamine additive is 5%.

[0050] This embodiment also provides a method for preparing the above-mentioned dual-responsive eutectic solvent, the preparation method comprising the following steps:

[0051] The first hydrogen bond donor, the second hydrogen bond donor, the hydrogen bond acceptor, and the additive were heated at 60°C for 40 minutes according to the formulation to obtain the dual-responsive eutectic solvent.

[0052] Example 3

[0053] This embodiment provides a dual-responsive eutectic solvent, which includes a first hydrogen bond donor, a second hydrogen bond donor, a choline chloride hydrogen bond acceptor, and a triethanolamine additive. The first hydrogen bond donor is o-nitrophenyl-polyethylene glycol-400, and the second hydrogen bond donor is p-toluenesulfonamide.

[0054] Of these, based on the total molar amount of all hydrogen bond donors as 100%, the molar percentage of o-nitrophenyl-polyethylene glycol-400 is 30%, and the molar percentage of p-toluenesulfonamide is 70%; the molar ratio of the combination of the first and second hydrogen bond donors to the hydrogen bond acceptor is 6:1; and based on the total mass of the dual-responsive eutectic solvent as 100%, the mass percentage of triethanolamine additive is 15%.

[0055] This embodiment also provides a method for preparing the above-mentioned dual-responsive eutectic solvent, the preparation method comprising the following steps:

[0056] The first hydrogen bond donor, the second hydrogen bond donor, the hydrogen bond acceptor, and the additives were heated at 80°C for 20 minutes according to the formulation to obtain the dual-responsive eutectic solvent.

[0057] Example 4

[0058] The difference between this embodiment and Example 1 is that, with the total molar amount of all hydrogen bond donors being 100%, the molar percentage of o-nitrophenyl-polyethylene glycol-400 is 20%, the molar percentage of p-toluenesulfonamide is 80%, and everything else is the same as in Example 1.

[0059] Example 5

[0060] The difference between this embodiment and Example 1 is that, with the total molar amount of all hydrogen bond donors being 100%, the molar percentage of o-nitrophenyl-polyethylene glycol-400 is 80%, the molar percentage of p-toluenesulfonamide is 20%, and everything else is the same as in Example 1.

[0061] Example 6

[0062] The difference between this embodiment and Embodiment 1 is that the molar ratio of hydrogen bond donor to hydrogen bond acceptor is 1:1, while all other aspects are the same as in Embodiment 1.

[0063] Example 7

[0064] The difference between this embodiment and Embodiment 1 is that the molar ratio of hydrogen bond donor to hydrogen bond acceptor is 10:1, while all other aspects are the same as in Embodiment 1.

[0065] Example 8

[0066] The difference between this embodiment and Example 1 is that o-nitrophenyl-polyethylene glycol-400 is replaced with an equimolar percentage of azophenyl-polyethylene glycol-400, while all other aspects are the same as in Example 1.

[0067] Example 9

[0068] The difference between this embodiment and Example 1 is that p-toluenesulfonamide is replaced with an equimolar percentage of N-isopropylacrylamide, while all other aspects are the same as in Example 1.

[0069] Comparative Example 1

[0070] The difference between this comparative example and Example 1 is that o-nitrophenyl-polyethylene glycol-400 is replaced with an equimolar percentage of p-toluenesulfonamide; all other aspects are the same as in Example 1.

[0071] Comparative Example 2

[0072] The difference between this comparative example and Example 1 is that p-toluenesulfonamide is replaced with an equimolar percentage of o-nitrophenyl-polyethylene glycol-400, while all other aspects are the same as in Example 1.

[0073] Comparative Example 3

[0074] The difference between this comparative example and Example 1 is that o-nitrophenyl-polyethylene glycol-400 is replaced with equimolar percentages of polyethylene glycol-400, while all other aspects are the same as in Example 1.

[0075] Application Example 1

[0076] This application example provides a method for recovering metal elements from waste lithium nickel cobalt manganese oxide cathode sheets, the method comprising the following steps:

[0077] At a light intensity of 30mW / cm 2 Under certain conditions, the waste lithium nickel cobalt manganese oxide cathode sheet to be recycled is reacted with the dual-responsive eutectic solvent provided in Example 1 at a solid-liquid ratio of 1:80 to obtain a lithium-rich leachate and a chelate precipitate containing transition metal ions.

[0078] The contents of nickel, cobalt, manganese and lithium in the leachate and its precipitate were determined by inductively coupled plasma atomic emission spectrometry (ICP-OES). The detection method followed the international standard ISO 11885 "Water quality - Inductively coupled plasma atomic emission spectrometry (ICP-OES)". The detection results of each metal are shown in Table 1.

[0079] Table 1

[0080]

[0081] Application Example 2

[0082] The difference between this application example and application example 1 is that the dual-responsive eutectic solvent provided in example 2 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 2.

[0083] Table 2

[0084]

[0085] Application Example 3

[0086] The difference between this application example and application example 1 is that the dual-responsive eutectic solvent provided in example 3 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 3.

[0087] Table 3

[0088]

[0089] Application Example 4

[0090] The difference between this application example and application example 1 is that the dual-responsive eutectic solvent provided in example 4 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 4.

[0091] Table 4

[0092]

[0093] Application Example 5

[0094] The difference between this application example and application example 1 is that the dual-responsive eutectic solvent provided in example 5 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 5.

[0095] Table 5

[0096]

[0097] Application Example 6

[0098] The difference between this application example and application example 1 is that the dual-responsive eutectic solvent provided in example 6 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 6.

[0099] Table 6

[0100]

[0101] Application Example 7

[0102] The difference between this application example and application example 1 is that the dual-responsive eutectic solvent provided in example 7 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 7.

[0103] Table 7

[0104]

[0105] Application Example 8

[0106] The difference between this application example and application example 1 is that the dual-responsive eutectic solvent provided in example 8 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 8.

[0107] Table 8

[0108]

[0109] Application Example 9

[0110] The difference between this application example and application example 1 is that the dual-responsive eutectic solvent provided in example 9 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 9.

[0111] Table 9

[0112]

[0113] Comparative Application Example 1

[0114] The difference between this comparative application example and application example 1 is that the dual-responsive eutectic solvent provided in comparative example 1 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 10.

[0115] Table 10

[0116]

[0117] Comparative Application Example 2

[0118] The difference between this comparative application example and application example 1 is that the dual-responsive eutectic solvent provided in comparative example 2 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 11.

[0119] Table 11

[0120]

[0121] Comparative Application Example 3

[0122] The difference between this comparative application example and application example 1 is that the dual-responsive eutectic solvent provided in comparative example 3 is used. All other aspects are the same as in application example 1. The detection results of each metal are shown in Table 12.

[0123] Table 12

[0124]

[0125] In summary, by rationally optimizing the composition of the eutectic solvent, this invention can achieve efficient extraction of key metals such as lithium, nickel, cobalt and manganese from positive electrode active materials, significantly improve the recovery rate and reduce energy consumption and chemical reagent usage, thereby achieving greener and more economical resource recycling.

[0126] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A dual-responsive eutectic solvent, characterized in that, The dual-responsive eutectic solvent includes a hydrogen bond donor and a hydrogen bond acceptor, wherein the hydrogen bond donor includes a first hydrogen bond donor and a second hydrogen bond donor; The first hydrogen bond donor includes a polyol compound containing a photoresponsive group, and the second hydrogen bond donor includes a thermosensitive compound.

2. The dual-responsive eutectic solvent according to claim 1, characterized in that, The photoresponsive group includes o-nitrophenyl; Preferably, the polypolyol compound containing photoresponsive groups includes o-nitrophenyl-polyethylene glycol-400.

3. The dual-responsive eutectic solvent according to claim 1 or 2, characterized in that, The thermosensitive compound includes at least one of p-toluenesulfonamide, N-ethyl-p-toluenesulfonamide, or N-methyl-p-toluenesulfonamide.

4. The dual-responsive eutectic solvent according to any one of claims 1-3, characterized in that, With the total molar amount of the hydrogen bond donors being 100%, the molar percentage of the first hydrogen bond donor is 30% to 70%. Preferably, with the total molar amount of the hydrogen bond donor being 100%, the molar percentage of the second hydrogen bond donor is 30% to 70%.

5. The dual-responsive eutectic solvent according to any one of claims 1-4, characterized in that, The hydrogen bond acceptor includes choline chloride; Preferably, the dual-responsive eutectic solvent further includes functional additives; Preferably, the functional additive includes triethanolamine; Preferably, the functional additive has a mass percentage content of 5% to 15%, based on the total mass of the dual-responsive eutectic solvent as 100%.

6. The dual-responsive eutectic solvent according to any one of claims 1-5, characterized in that, The molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is (2~6):

1.

7. A method for preparing a dual-responsive eutectic solvent as described in any one of claims 1-6, characterized in that, The preparation method includes the following steps: The first hydrogen bond donor, the second hydrogen bond donor, and the hydrogen bond acceptor are heated for the first time to obtain the dual-responsive eutectic solvent, wherein the first hydrogen bond donor includes a polyol compound containing a photoresponsive group, and the second hydrogen bond donor includes a thermosensitive compound.

8. The preparation method according to claim 7, characterized in that, The temperature of the first heating is 60℃~80℃, and the heating time is 20min~50min.

9. A method for recycling metal elements from waste positive electrode plates, characterized in that, The method includes the following steps: Under light or secondary heating conditions, the waste positive electrode sheet to be recycled is reacted with a dual-responsive eutectic solvent as described in any one of claims 1-6 to obtain a lithium-rich leachate and a chelate containing transition metal ions.

10. The method according to claim 9, characterized in that, The illumination conditions are: light intensity of 10 mW / cm². 2 ~50mW / cm 2 ; Preferably, the temperature of the second heating is 60℃~90℃, and the duration of the second heating is 2h~6h; Preferably, the solid-liquid ratio of the waste positive electrode sheet to be recycled to the dual-responsive eutectic solvent is 1:(70-90).

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