Carbon-supported phenolic resin and its preparation method and application

Abstract

The present invention relates to a carbon-supported phenolic resin and a preparation method and application thereof. The carbon-supported phenolic resin comprises a carbon support and a phenolic resin, wherein the phenolic resin is grafted onto the carbon support, wherein the structural unit of the phenolic resin comprises an aromatic phenol, and the aromatic phenol is connected with more than two hydroxyl groups. The carbon-supported phenolic resin has the advantages of large specific surface area, large adsorption capacity, and strong adsorption selectivity for silicon, and can be used as a highly selective silicon removal adsorbent.

Description

Technical Field

[0001] The invention relates to the technical field of adsorbents, and in particular to a carbon-supported phenolic resin and a preparation method and application thereof. Background Art

[0002] As an important energy storage device, lithium batteries are widely used in modern society. However, lithium batteries need to be recycled and processed at the end of their service life to reduce negative impacts on the environment and achieve the reuse of limited resources.

[0003] During the recycling process, discarded lithium batteries undergo a series of physical and chemical processing steps, including decomposing the battery, recovering the electrolyte, extracting metals, etc. However, silicon becomes a challenge in this process. Silicon is usually present in the negative electrode material of lithium batteries, and lithium batteries produced by different manufacturers contain different amounts of silicon. The presence of silicon may cause a series of problems in the recycling process, as follows:

[0004] First, silicon can react with other metals to form impurities or lumps, reducing the purity and quality of the recycled materials. Second, silicon may also increase the viscosity of the battery recycling fluid, resulting in poor fluidity and affecting the efficiency of subsequent processing steps. In addition, the presence of silicon can also cause corrosion and wear on equipment and processes.

[0005] In order to solve these problems, silicon removal technology in lithium battery recycling liquid came into being. The more mature methods for silicon removal in lithium solutions that have been reported include precipitation, solvent extraction, ion exchange, adsorption separation and other methods. These technologies can effectively remove silicon from the recycling liquid by physical or chemical means. Physical methods often include steps such as screening and centrifugation, and remove silicon-containing particles or substances by particle size selection and solid-liquid separation. Chemical methods use adsorption, acidic or alkaline solutions to react, and then filter or precipitate to separate. Through the application of silicon removal technology, the purity and quality of the recycling liquid can be improved, the corrosion and wear of equipment can be reduced, the generation of waste can be reduced, and a more sustainable and environmentally friendly solution can be provided for the recycling and reuse of lithium batteries. With the continuous improvement of the development of these technologies, they have made important contributions to the realization of circular economy and efficient utilization of resources. In particular, the adsorption method has attracted much attention for its advantages such as low cost, easy operation and high silicon removal rate, but traditional silicon removal adsorbents have problems such as small adsorption capacity and poor adsorption selectivity, which urgently need to be improved. Summary of the invention

[0006] Based on this, the present invention provides a carbon-supported phenolic resin, which has a large specific surface area, a large adsorption capacity, and a strong adsorption selectivity for silicon, and can be used as a highly selective silicon removal adsorbent.

[0007] The technical solution is as follows:

[0008] A carbon-supported phenolic resin comprises a carbon carrier and a phenolic resin, wherein the phenolic resin is grafted onto the carbon carrier, the structural unit of the phenolic resin comprises aromatic phenol, and the aromatic phenol is connected with more than two hydroxyl groups.

[0009] In one embodiment, the number of ring atoms in the aromatic ring of each aromatic phenol is independently 6 to 30.

[0010] In one embodiment, each of the aromatic phenols is independently connected to 2 or 3 hydroxyl groups.

[0011] In one embodiment, the aromatic phenol is selected from one or more of catechol and pyrogallol.

[0012] In one embodiment, the weight average molecular weight of the phenolic resin is 50000 g / mol to 80000 g / mol.

[0013] In one embodiment, the type of the carbon carrier is selected from one or more of carbon nanotubes, carbon black, mesoporous carbon and carbon aerogel.

[0014] In one embodiment, the carbon carrier contains multiple functional groups, and the functional groups include 1% to 3% carbonyl and 4% to 8% carboxyl, based on molar percentage of the total amount of functional groups of the carbon carrier.

[0015] In one embodiment, the molar ratio of the carbon support to the aromatic phenol in the phenolic resin is (1-3):1.

[0016] In one embodiment, the carbon carrier is a carbon nanotube, the carbon nanotube has an average diameter of 10 nm to 20 nm, an average length of 5 μm to 20 μm, and an aspect ratio of 500 to 1000.

[0017] The present invention also provides a method for preparing the carbon-supported phenolic resin as described above, comprising the following steps:

[0018] Acidifying the carbon material to prepare the carbon carrier;

[0019] The carbon carrier is mixed with formaldehyde, aromatic phenol and a pH regulator to prepare the carbon-supported phenolic resin through a polymerization reaction.

[0020] In one embodiment, the acidification treatment comprises the following steps:

[0021] The carbon material and the acid are mixed and refluxed at 60° C. to 90° C. for 6 h to 9 h.

[0022] In one embodiment, the acid is selected from one or more of nitric acid, sulfuric acid and hydrochloric acid.

[0023] In one embodiment, after the acidification step, the following steps are also included:

[0024] The product after the acidification treatment is subjected to one or more treatments selected from the group consisting of suction filtration, washing, drying and screening.

[0025] In one embodiment, the mesh size of the sieve used in the sieving process is 150-250 meshes.

[0026] In one embodiment, the molar ratio of the carbon carrier, the formaldehyde and the aromatic phenol is (1-3):(0.7-0.9):1.

[0027] In one embodiment, the pH of the polymerization reaction system is 1 to 3, the polymerization reaction temperature is 60° C. to 90° C., and the polymerization reaction time is 1 h to 3 h.

[0028] In one embodiment, the pH adjuster is selected from one or more of oxalic acid, folic acid and citric acid.

[0029] In one embodiment, the mass ratio of the pH regulator to the aromatic phenol is (1-2):100.

[0030] The present invention also provides an adsorbent, comprising the carbon-supported phenolic resin as described above, or the carbon-supported phenolic resin prepared according to the preparation method of the carbon-supported phenolic resin as described above.

[0031] In one embodiment, the adsorbent is a lithium battery recovery liquid desiliconization adsorbent.

[0032] The present invention has the following beneficial effects:

[0033] The carbon-supported phenolic resin provided by the present invention comprises a carbon carrier and a phenolic resin, and the structural unit of the phenolic resin comprises aromatic phenol, and the aromatic phenol is connected to more than two hydroxyl groups. The hydroxyl groups in the aromatic phenol can chelate with silicon to form a stable chelate, showing excellent ability to selectively adsorb silicon, and is suitable for selective adsorption and separation of silicon in a complex multi-element environment. Since the carbon carrier has a large specific surface area, the phenolic resin is grafted onto the carbon carrier to achieve specific high-capacity adsorption of silicon.

[0034] After testing, the carbon-supported phenolic resin provided in the embodiment of the present invention is used as a silicon removal adsorbent. When the solution contains multiple element ions (iron ions, cobalt ions, nickel ions, silicate ions, manganese ions and lithium ions), the carbon-supported phenolic resin adsorption material of the present invention can adsorb a large amount of silicon, but has poor adsorption for iron ions, cobalt ions, nickel ions, manganese ions and lithium ions, indicating that the carbon-supported phenolic resin of the present invention has high adsorption selectivity for silicon. After being recycled for 5 times, the adsorption capacity for silicon remains basically unchanged, showing excellent stability, and can be used as a stable and highly selective silicon removal adsorbent or silicon removal adsorbent material.

[0035] In addition, the preparation method of the carbon-supported phenolic resin provided by the present invention has simple and easy-to-control process, simple operation, low reagent cost, mild conditions, low equipment investment, green and environmental protection, no toxic and harmful gases are generated during the preparation process, the use of toxic reagents and dangerous surface treatment methods is reduced, the yield is high, the product is pure, the product is easy to recycle, the quality is controllable and it is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a physical picture of the carbon-supported phenolic resin prepared in Example 1 of the present invention;

[0037] Figure 2 is an infrared spectrum of the carbon-supported phenolic resin prepared in Example 1 of the present invention;

[0038] Figure 3 is a SEM image of the carbon-supported phenolic resin prepared in Example 1 of the present invention;

[0039] Figure 4 The carbon-supported phenolic resin prepared in Example 1 of the present invention is used as a silicon removal adsorption material for five cycles to obtain the adsorption capacity of silicon. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below in conjunction with specific embodiments and accompanying drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0042] Where “including,” “having,” and “comprising” are used herein, it is intended to cover a non-exclusive inclusion, and another component may also be added unless explicit limiting terms such as “only,” “consisting of,” etc. are used.

[0043] The words "preferably", "more preferably", "preferably", "better", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the statement of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention. That is, in the present invention, "preferably", "more preferably", "preferably", "better", etc. are only used to describe implementation methods or examples with better effects, but do not constitute a limitation on the scope of protection of the present invention.

[0044] In the present invention, “further”, “furthermore”, “particularly”, etc. are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present invention.

[0045] In the present invention, "at least one" means more than one, such as one, two and more than two. "Multiple" or "several" means at least two, such as two, three, etc., and "multilayer" means at least two layers, such as two layers, three layers, etc., unless otherwise clearly and specifically defined. In the description of the present invention, "several" means at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0046] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0047] If not otherwise specified, all steps of the present invention may be performed sequentially or randomly. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0048] In the present invention, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0049] The temperature parameters in the present invention, if not specifically limited, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the precision range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0050] Unless mentioned to the contrary, terms in the singular may include plural forms and should not be construed as being one in number.

[0051] In the present invention, "A and B are independently selected from x, y or z" means that A and B are independent events, and event A does not affect the occurrence of event B. Therefore, when A is selected from x, B can be selected from any one of x, y or z; when A is selected from y, B can be selected from any one of x, y or z; when A is selected from z, B can be selected from any one of x, y or z.

[0052] "Aryl or aromatic group or aromatic radical" refers to an aromatic hydrocarbon radical derived from an aromatic ring compound by removing a hydrogen atom, which may be a monocyclic aromatic radical, a condensed aromatic radical, or a polycyclic aromatic radical. For polycyclic rings, at least one is an aromatic ring system. For example, "substituted or unsubstituted aromatic radical having 6 to 40 ring atoms" refers to a substituted or unsubstituted aromatic radical containing 6 to 40 ring atoms, preferably an aromatic radical having 6 to 30 ring atoms, more preferably an aromatic radical having 6 to 18 ring atoms, and particularly preferably an aromatic radical having 6 to 14 ring atoms, and the aromatic radical may be further substituted; suitable examples include, but are not limited to, benzene, biphenyl, terphenyl, naphthalene, anthracene, fluoranthene, phenanthrene, triphenylene, perylene, tetracene, pyrene, benzopyrene, acenaphthene, fluorene and derivatives thereof. It is understandable that multiple aromatic groups may also be interrupted by short non-aromatic units (e.g. <10% non-H atoms, such as C, N or O atoms), specifically acenaphthene, fluorene, or 9,9-diarylfluorene, triarylamine, diaryl ether systems should also be included in the definition of aromatic groups.

[0053] In the present invention, the "number of ring atoms" refers to the number of atoms in the atoms constituting the ring itself of a structural compound (e.g., a monocyclic compound, a condensed ring compound, a cross-linked compound, a carbocyclic compound, a heterocyclic compound) in which atoms are bonded to form a ring. When the ring is substituted with a substituent, the atoms contained in the substituent are not included in the ring atoms. The same is true for the "number of ring atoms" described below unless otherwise specified. For example, the number of ring atoms of a benzene ring is 6, the number of ring atoms of a naphthalene ring is 10, and the number of ring atoms of a thienyl group is 5.

[0054] The raw materials, reagents and materials used in the following specific embodiments are all commercially available products unless otherwise specified.

[0055] Traditional silicon removal adsorbents have the problems of small adsorption capacity and poor adsorption selectivity, which need to be improved. Based on this, the present invention provides a carbon-supported phenolic resin, which has a large specific surface area, a large adsorption capacity, and a strong adsorption selectivity for silicon, and can be used as a highly selective silicon removal adsorbent.

[0056] The technical solution is as follows:

[0057] A carbon-supported phenolic resin comprises a carbon carrier and a phenolic resin, wherein the phenolic resin is grafted onto the carbon carrier, the structural unit of the phenolic resin comprises aromatic phenol, and the aromatic phenol is connected with more than two hydroxyl groups.

[0058] The hydroxyl groups in aromatic phenol can chelate with silicon to form a stable chelate, showing excellent ability to selectively adsorb silicon and is suitable for selective adsorption and separation of silicon in a complex multi-element environment. Due to the large specific surface area of ​​the carbon carrier, grafting phenolic resin on the carbon carrier can achieve specific high-capacity adsorption of silicon.

[0059] In one embodiment, the number of ring atoms of the aromatic ring in each of the aromatic phenols is independently 6 to 30, including but not limited to 6, 10, 15, 20, 24 or 30. Further, the number of ring atoms of each aromatic ring is independently 6 to 20. In a specific example, the number of ring atoms of each aromatic ring is independently 6 to 10.

[0060] In one embodiment, each of the aromatic phenols is independently connected to 2 or 3 hydroxyl groups.

[0061] In one embodiment, the aromatic phenol is selected from one or more of catechol and pyrogallol.

[0062] In one embodiment, the weight average molecular weight of the phenolic resin is 50000 g / mol to 80000 g / mol.

[0063] In one embodiment, the type of the carbon carrier is selected from one or more of carbon nanotubes, carbon black, mesoporous carbon and carbon aerogel.

[0064] In one embodiment, the carbon carrier contains multiple functional groups, and the functional groups include 1% to 3% carbonyl and 4% to 8% carboxyl, based on molar percentage of the total amount of functional groups of the carbon carrier.

[0065] In one embodiment, the carbon carrier contains a plurality of functional groups, and the functional groups include 1% to 2% carbonyl and 4% to 6% carboxyl, based on molar percentage of the total amount of functional groups of the carbon carrier.

[0066] In one embodiment, the carbon carrier contains multiple functional groups, and the functional groups include 2% to 3% carbonyl and 6% to 8% carboxyl in terms of molar percentage of the total amount of functional groups of the carbon carrier.

[0067] In one embodiment, the molar ratio of the carbon support to the aromatic phenol in the phenolic resin is (1-3):1, including but not limited to 1:1, 2:1 or 3:1.

[0068] In one embodiment, the carbon carrier is a carbon nanotube, the average diameter of the carbon nanotube is 10nm-20nm, the average length is 5μm-20μm, and the aspect ratio is 500-1000. It can be understood that the aspect ratio of the carbon nanotube includes but is not limited to 500, 600, 800, 900 or 1000.

[0069] The present invention also provides a method for preparing the carbon-supported phenolic resin as described above, comprising the following steps:

[0070] Acidifying the carbon material to prepare the carbon carrier;

[0071] The carbon carrier is mixed with formaldehyde, aromatic phenol and a pH regulator to prepare the carbon-supported phenolic resin through a polymerization reaction.

[0072] In one embodiment, the acidification treatment comprises the following steps:

[0073] The carbon material and the acid are mixed and refluxed at 60° C. to 90° C. for 6 h to 9 h.

[0074] It can be understood that the temperature of the acidification treatment includes but is not limited to 60°C, 70°C, 80°C or 90°C, preferably 80°C to 90°C.

[0075] It can be understood that the time of the acidification treatment includes but is not limited to 6 h, 7 h, 8 h or 9 h, preferably 6 h to 7 h.

[0076] In one embodiment, the acid is selected from one or more of nitric acid, sulfuric acid and hydrochloric acid.

[0077] In one specific example, the acid used in the acidification treatment is hydrochloric acid.

[0078] In one embodiment, the concentration of the acid is 5M to 6M, and the amount of the acid used is 300mL to 500mL for 100g of carbon material.

[0079] In one embodiment, after the acidification step, the following steps are also included:

[0080] The product after the acidification treatment is subjected to one or more treatments selected from the group consisting of suction filtration, washing, drying and screening.

[0081] In one embodiment, after the acidification step, the following steps are also included:

[0082] The product after the acidification treatment is filtered, washed, dried and sieved in sequence.

[0083] In one embodiment, the mesh size of the sieve used for the sieving process is 150-250 meshes, including but not limited to 150 meshes, 180 meshes, 200 meshes, 220 meshes or 250 meshes.

[0084] In one embodiment, the molar ratio of the carbon carrier, the formaldehyde and the aromatic phenol is (1-3):(0.7-0.9):1, including but not limited to 1:0.7:1, 1:0.8:1, 1:0.9:1, 2:0.7:1, 2:0.8:1, 2:0.9:1, 3:0.7:1, 3:0.8:1 or 3:0.9:1.

[0085] In one embodiment, the pH of the polymerization reaction system is 1-3, including but not limited to 1, 1.5, 2 or 3, preferably 1-2.

[0086] In one embodiment, the pH adjuster is selected from one or more of oxalic acid, folic acid and citric acid.

[0087] In one embodiment, the mass ratio of the pH regulator to the aromatic phenol is (1-2):100.

[0088] In one embodiment, the polymerization reaction temperature is 60°C to 90°C, including but not limited to 60°C, 70°C, 80°C or 90°C, preferably 70°C to 75°C.

[0089] In one embodiment, the polymerization reaction time is 1 h to 3 h, including but not limited to 1 h, 2 h or 3 h.

[0090] In one embodiment, during the polymerization reaction, the stirring speed is 200 rpm to 800 rpm.

[0091] The present invention also provides an adsorbent, comprising the carbon-supported phenolic resin as described above, or the carbon-supported phenolic resin prepared according to the preparation method of the carbon-supported phenolic resin as described above.

[0092] In one embodiment, the adsorbent is a lithium battery recovery liquid desiliconization adsorbent.

[0093] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described below in conjunction with specific embodiments and comparative examples. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention.

[0094] The average diameter of the carbon nanotubes used in the following examples and comparative examples is 10 nm to 20 nm.

[0095] Example 1

[0096] This embodiment provides a carbon-supported phenolic resin and a preparation method thereof, which are specifically as follows:

[0097] (a) Acidification of carbon nanotubes: 100 g of carbon nanotubes were placed in a single-necked flask containing 500 mL of 5M acid solution, stirred for 1 hour to make it evenly distributed, and refluxed at 80 °C for 6 hours;

[0098] (b) screening: filtering, washing, drying and sieving (200 mesh) the material in step (a) to obtain a carbon support, wherein the functional groups include 1.5% carbonyl and 5% carboxyl, based on the molar percentage of the total amount of functional groups of the carbon support;

[0099] (c) Phenol condensation: add carbon support, formaldehyde and pyrogallol in a molar ratio of 1:0.7:1 into a three-necked flask, stir evenly, add oxalic acid as a catalyst, adjust the solution pH to 1-2, the amount of oxalic acid added is 3wt% of pyrogallol, then heat to 70°C, react for 1.5h, and the weight average molecular weight of the phenolic resin is 50000g / mol;

[0100] (d) Purification: The material obtained in step (c) is filtered, washed, and dried to obtain a carbon-supported phenolic resin, which is referred to as product A.

[0101] Figure 1 This is a physical picture of the carbon-supported phenolic resin prepared in Example 1. It can be seen that it is a black powder.

[0102] Figure 2 This is the infrared spectrum of the carbon-supported phenolic resin obtained in Example 1. By analyzing its characteristic vibration peaks, it can be seen that the carbon carrier successfully supports the phenolic resin.

[0103] Figure 3 is a SEM image of the carbon-supported phenolic resin prepared in Example 1. It can be seen that the phenolic resin is uniformly supported on the carbon support.

[0104] Example 2

[0105] This embodiment provides a carbon-supported phenolic resin and a preparation method thereof, which are specifically as follows:

[0106] (a) Acidification of carbon nanotubes: 100 g of carbon nanotubes were placed in a single-necked flask containing 500 mL of 5M acid solution, stirred for 1 hour to make it evenly distributed, and refluxed at 80 °C for 6 hours;

[0107] (b) screening: filtering, washing, drying and sieving (200 mesh) the material in step (a) to obtain a carbon support, wherein the functional groups include 1.5% carbonyl and 5% carboxyl, based on the molar percentage of the total amount of functional groups of the carbon support;

[0108] (c) Phenol condensation: add the treated carbon support, formaldehyde and pyrogallol in a molar ratio of 1:0.7:1 to a three-necked flask, stir evenly, add oxalic acid as a catalyst, adjust the solution pH to 1-2, the amount of oxalic acid added is 3wt% of pyrogallol, then heat to 90°C and react for 1.5h; the weight average molecular weight of the obtained phenolic resin is 76000g / mol;

[0109] (d) Purification: The material obtained in step (c) is filtered, washed, and dried to obtain a carbon-supported phenolic resin, which is referred to as product B.

[0110] Example 3

[0111] This embodiment provides a carbon-supported phenolic resin and a preparation method thereof, which are specifically as follows:

[0112] (a) Acidification of carbon nanotubes: 100 g of carbon nanotubes were placed in a single-necked flask containing 500 mL of 5M acid solution, stirred for 1 hour to make it evenly distributed, and refluxed at 80 °C for 6 hours;

[0113] (b) screening: filtering, washing, drying and sieving (200 mesh) the material in step (a) to obtain a carbon support, wherein the functional groups include 1.5% carbonyl and 5% carboxyl, based on the molar percentage of the total amount of functional groups of the carbon support;

[0114] (c) Phenol condensation: add the treated carbon support, formaldehyde and pyrogallol in a molar ratio of 1:0.7:1 to a three-necked flask, stir evenly, add oxalic acid as a catalyst, adjust the solution pH to 1-2, the amount of oxalic acid added is 3wt% of pyrogallol, then heat to 70°C and react for 3h; the weight average molecular weight of the obtained phenolic resin is 68000g / mol;

[0115] (d) Purification: The material obtained in step (c) is filtered, washed, and dried to obtain a carbon-supported phenolic resin, which is referred to as product C.

[0116] Example 4

[0117] This embodiment provides a carbon-supported phenolic resin and a preparation method thereof, which are specifically as follows:

[0118] (a) Acidification of carbon nanotubes: 100 g of carbon nanotubes were placed in a single-necked flask containing 500 mL of 5M acid solution, stirred for 1 hour to make it evenly distributed, and refluxed at 80 °C for 6 hours;

[0119] (b) screening: filtering, washing, drying and sieving (200 mesh) the material in step (a) to obtain a treated carbon nanotube carrier, wherein the functional groups include 1.5% carbonyl and 5% carboxyl, based on the molar percentage of the total amount of functional groups of the carbon carrier;

[0120] (c) Phenol condensation: add the treated carbon support, formaldehyde and pyrogallol in a molar ratio of 1:0.7:1 to a three-necked flask, stir evenly, add oxalic acid as a catalyst, adjust the solution pH to 2-3, the amount of oxalic acid added is 2wt% of pyrogallol, then heat to 70°C and react for 1.5h; the weight average molecular weight of the obtained phenolic resin is 53000g / mol;

[0121] (d) Purification: The material obtained in step (c) is filtered, washed, and dried to obtain a carbon-supported phenolic resin, which is referred to as product D.

[0122] Example 5

[0123] This embodiment provides a carbon-supported phenolic resin and a preparation method thereof, which are specifically as follows:

[0124] (a) Acidification of carbon nanotubes: 100 g of carbon nanotubes were placed in a single-necked flask containing 500 mL of 5M acid solution, stirred for 1 hour to make it evenly distributed, and refluxed at 80 °C for 6 hours;

[0125] (b) screening: filtering, washing, drying and sieving (200 mesh) the material in step (a) to obtain a carbon support, wherein the functional groups include 1.5% carbonyl and 5% carboxyl, based on the molar percentage of the total amount of functional groups of the carbon support;

[0126] (c) Phenol condensation: add the treated carbon support, formaldehyde and pyrogallol in a molar ratio of 1:0.8:1 to a three-necked flask, stir evenly, add oxalic acid as a catalyst, adjust the solution pH to 1-2, the amount of oxalic acid added is 3wt% of pyrogallol, then heat to 90°C and react for 3h; the weight average molecular weight of the obtained phenolic resin is 80000g / mol;

[0127] (d) Purification: The material obtained in step (c) is filtered, washed, and dried to obtain a carbon-supported phenolic resin, which is referred to as product E.

[0128] Example 6

[0129] This embodiment provides a carbon-supported phenolic resin and a preparation method thereof, which are specifically as follows:

[0130] (a) Acidification of carbon nanotubes: 100 g of carbon nanotubes were placed in a single-necked flask containing 500 mL of 5M acid solution, stirred for 1 hour to make it evenly distributed, and refluxed at 80° C. for 6 hours.

[0131] (b) screening: filtering, washing, drying and sieving (200 mesh) the material in step (a) to obtain a treated carbon nanotube carrier, wherein the functional groups include 1.5% carbonyl and 5% carboxyl, based on the molar percentage of the total amount of functional groups of the carbon carrier;

[0132] (c) Phenolic condensation: Add the treated carbon support, formaldehyde and catechol in a molar ratio of 1:0.8:1 to a three-necked flask, stir evenly, add oxalic acid as a catalyst, adjust the solution pH to 1-2, and add oxalic acid in an amount of 3wt% of catechol, then heat to 90°C and react for 3h; the weight average molecular weight of the obtained phenolic resin is 78000g / mol;

[0133] (d) Purification: The material obtained in step (c) is filtered, washed and dried to obtain a carbon-supported phenolic resin adsorption material, which is recorded as product F.

[0134] Example 7

[0135] This embodiment provides a carbon-supported phenolic resin and a preparation method thereof, which are specifically as follows:

[0136] (a) Acidification of carbon nanotubes: 100 g of carbon nanotubes were placed in a single-necked flask containing 500 mL of 6M acid solution, stirred for 1 hour to make it evenly distributed, and refluxed at 90 °C for 9 hours;

[0137] (b) screening: filtering, washing, drying and sieving (200 mesh) the material in step (a) to obtain a carbon support, wherein the functional groups include 3% carbonyl and 8% carboxyl, based on the molar percentage of the total amount of functional groups of the carbon support;

[0138] (c) Phenol condensation: add the treated carbon support, formaldehyde and pyrogallol in a molar ratio of 1:0.8:1 to a three-necked flask, stir evenly, add oxalic acid as a catalyst, adjust the solution pH to 1-2, the amount of oxalic acid added is 3wt% of pyrogallol, then heat to 90°C and react for 3h; the weight average molecular weight of the obtained phenolic resin is 77000g / mol;

[0139] (d) Purification: The material obtained in step (c) is filtered, washed, and dried to obtain a carbon-supported phenolic resin, which is referred to as product G.

[0140] Comparative Example 1

[0141] This comparative example provides a carbon-supported phenolic resin and a preparation method thereof, which are specifically as follows:

[0142] (a) Acidification of carbon nanotubes: 100 g of carbon nanotubes were placed in a single-necked flask containing 500 mL of 5M acid solution, stirred for 1 hour to make it evenly distributed, and refluxed at 80 °C for 6 hours;

[0143] (b) screening: filtering, washing, drying and sieving (200 mesh) the material in step (a) to obtain a carbon support, wherein the functional groups include 1.5% carbonyl and 5% carboxyl, based on the molar percentage of the total amount of functional groups of the carbon support;

[0144] (c) Phenolic condensation: add the treated carbon support, formaldehyde and phenol in a molar ratio of 1:0.8:1 into a three-necked flask, stir evenly, add oxalic acid as a catalyst, adjust the solution pH to 1-2, and add oxalic acid in an amount of 3wt% of phenol, then heat to 90°C and react for 3h;

[0145] (d) Purification: The material obtained in step (c) is filtered, washed, and dried to obtain a carbon-supported phenolic resin, which is referred to as product H.

[0146] Comparative Example 2

[0147] The commercially available product, desilicyl, is recorded as Product I.

[0148] The performance test of the products obtained in Examples 1 to 7 and Comparative Examples 1 to 2 was performed as follows:

[0149] 1. Investigate the adsorption selectivity of each adsorption material for silicon:

[0150] (1) 10 g of the carbon-supported phenolic resin prepared in Examples 1 to 7 and Comparative Example 1, and 10 g to 20 g of the commercially available silicon removal material in Comparative Example 3 were added to a prepared solution containing 200 ppm of polymetallic ions (Fe 3+ , Cu 2+ 、Ni 2+ 、Co 2+ , Mn 3+ , Li + , Si exists in the form of silicate ions) in wastewater;

[0151] (2) The liquid in step (1) was placed in a 100 mL to 500 mL conical flask and oscillated in a constant temperature oscillator for 12 h to 24 h. The liquid was passed through a 0.45 μm membrane and the content of each ion was determined. The results are shown in Table 1.

[0152] Table 1 Ion content in lithium battery recovery liquid before and after adsorption

[0153]

[0154] It can be seen from Table 1 that in the presence of multi-metal ions in the solution, the carbon-supported phenolic resin material synthesized in the embodiment of the present invention can selectively adsorb silicon with excellent silicon adsorption performance, is suitable for the selective adsorption and separation of silicon in a complex multi-heavy element environment, and can be used as a silicon removal adsorbent.

[0155] 2. The carbon-supported phenolic resin prepared in Example 1 was used as a desiliconizing adsorbent and the commercially available desiliconizing adsorbent resin shown in Comparative Example 2 were tested for desiliconizing effects, as shown in Table 2 below.

[0156] Table 2 Comparison of silicon removal effects between carbon-supported phenolic resin and commercially available silicon removal adsorption resin in Example 1

[0157]

[0158] It can be clearly seen from Table 2 above that the carbon-supported phenolic resin synthesized in Example 1 of the present invention has excellent adsorption selectivity for silicon and maintains good adsorption performance at a flow rate of 4 BV / h.

[0159] 3. Test the stability of the carbon-supported phenolic resin prepared in Example 1 as a silicon removal adsorbent. Cycle 5 times and record the adsorption capacity for silicon. The results are as follows: Figure 4 As shown by Figure 4 It can be seen that the carbon-supported phenolic resin has a high adsorption selectivity for silicon. After being recycled for 5 times, the adsorption capacity for silicon remains basically unchanged, showing excellent stability, and can be used as a stable and highly selective silicon removal adsorbent.

[0160] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0161] The above-described embodiments only express several implementation methods of the present invention, which are convenient for understanding the technical solutions of the present invention in detail, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention. It should be understood that the technical solutions obtained by ordinary technicians in this field through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present invention are all within the protection scope of the claims attached to the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the contents of the attached claims, and the description and drawings can be used to explain the contents of the claims.

Claims

1. A carbon-supported phenolic resin, characterized in that: It comprises a carbon carrier and a phenolic resin, wherein the phenolic resin is grafted onto the carbon carrier, and the structural unit of the phenolic resin comprises aromatic phenol, and the aromatic phenol is pyrogallol; The carbon carrier is selected from carbon nanotubes, and the carbon carrier contains multiple functional groups, and the functional groups include 1% to 3% carbonyl and 4% to 8% carboxyl in terms of molar percentage of the total amount of functional groups of the carbon carrier; The preparation method of the carbon-supported phenolic resin comprises the following steps: Acidifying the carbon material to prepare the carbon carrier; The carbon carrier is mixed with formaldehyde, aromatic phenol and a pH regulator to prepare the carbon-supported phenolic resin through a polymerization reaction; The pH regulator is selected from one or more of oxalic acid, folic acid and citric acid; The mass ratio of the pH regulator to the aromatic phenol is (1-2):100; The molar ratio of the carbon carrier, the formaldehyde and the aromatic phenol is (1-3):(0.7-0.9):

1.

2. The carbon-supported phenolic resin according to claim 1, characterized in that: The functional groups include 2% to 3% carbonyl and 6% to 8% carboxyl.

3. The carbon-supported phenolic resin according to claim 1, characterized in that: The weight average molecular weight of the phenolic resin is 50000 g / mol to 80000 g / mol.

4. The carbon-supported phenolic resin according to claim 3, characterized in that: The carbon nanotubes have an average diameter of 10 nm to 20 nm, an average length of 5 μm to 20 μm, and an aspect ratio of 500 to 1000.

5. The carbon-supported phenolic resin according to any one of claims 1 to 4, characterized in that: The pH of the polymerization reaction system is 1 to 3, the polymerization reaction temperature is 60° C. to 90° C., and the polymerization reaction time is 1 h to 3 h.

6. The carbon-supported phenolic resin according to claim 5, characterized in that: Acidification treatment includes the following steps: The carbon material and the acid are mixed and refluxed at 60° C. to 90° C. for 6 h to 9 h.

7. The carbon-supported phenolic resin according to claim 5, characterized in that: After the acidification step, the following steps are also included: The product after the acidification treatment is subjected to one or more treatments selected from the group consisting of suction filtration, washing, drying and screening.

8. The carbon-supported phenolic resin according to claim 7, characterized in that: The mesh size of the sieve used for the sieving process is 150 to 250 meshes.

9. An adsorbent, characterized in that The invention comprises the carbon-supported phenolic resin according to any one of claims 1 to 8.

10. The adsorbent according to claim 9, characterized in that The adsorbent is a lithium battery recovery liquid desiliconizing adsorbent.

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