Solid phase extraction packing for removing metal ions from waste lubricant of steel cord and preparation method thereof

Abstract

The application relates to the field of industrial waste liquid treatment, in particular to a solid-phase extraction filler for removing metal ions in waste lubricant of steel cord and a preparation method. The solid-phase extraction filler for removing metal ions in waste lubricant of steel cord is a composite particle with a core-shell structure, which comprises a magnetic Fe3O4 inner core, a mesoporous silica gel adsorption layer coated outside the inner core, and a TiO2-SiO2 outer protective layer coated outside the adsorption layer; the pore inner surface of the mesoporous silica gel adsorption layer is bonded with amino and thiol bifunctional groups. The filler has the advantages of high adsorption capacity, high selectivity, strong anti-clogging capacity and easy recycling and regeneration, is particularly suitable for the recycling treatment of waste lubricant of steel cord drawing with complex components and easy clogging, can effectively remove copper and zinc ions in the waste lubricant, and realizes resource recycling.

Description

Technical Field

[0001] This application relates to the field of industrial waste liquid treatment, and in particular to a solid phase extraction packing for removing metal ions from waste lubricant in steel cord and its preparation method. Background Technology

[0002] In the wet drawing process of steel cord in the tire radial industry, a large amount of drawing lubricant is used. This lubricant is expensive and is one of the main costs in the production process of steel cord. After the lubricant fails, a large amount of high-concentration emulsion waste liquid is generated. The waste liquid contains high concentrations of copper and zinc ions, which affects the performance of the steel cord drawing lubricant. The waste liquid is difficult to treat and can easily cause environmental pollution.

[0003] Existing treatment methods such as chemical precipitation, ion exchange, and membrane separation have the following problems: chemical precipitation produces a large amount of sludge that is difficult to dispose of; ion exchange resins are easily contaminated and difficult to regenerate; and membrane separation is costly and prone to clogging.

[0004] Although solid-phase extraction technology has some applications, traditional packing materials have poor selectivity for copper and zinc ions and low adsorption capacity, making it difficult to operate stably in continuous industrial plants. Summary of the Invention

[0005] In order to design a solid-phase extraction packing material with high selectivity and high adsorption capacity to achieve efficient removal and resource recycling of copper and zinc ions in waste lubricants, this application provides a solid-phase extraction packing material for removing metal ions from waste lubricants of steel cord and its preparation method.

[0006] In the first aspect, this application provides a solid-phase extraction packing for removing metal ions from waste lubricant in steel cord, using the following technical solution;

[0007] A solid-phase extraction filler for removing metal ions from waste lubricant in steel cord is a composite particle with a core-shell structure, comprising a magnetic Fe3O4 core, a mesoporous silica adsorption layer covering the core, and a TiO2-SiO2 outer protective layer covering the adsorption layer; the inner surface of the pores of the mesoporous silica adsorption layer is bonded with amino and thiol bifunctional groups.

[0008] By adopting the above technical solution, a three-layer core-shell structure packing was designed. The magnetic Fe3O4 core facilitates rapid filling, fixation, and recovery of the packing material via an external magnetic field, significantly improving operational convenience and process continuity. The mesoporous silica adsorption layer provides ample adsorption sites through its high specific surface area, and the amino and thiol bifunctional groups bonded to the inner surface of its pores can synergistically coordinate Cu. 2+ Zn 2+This achieves highly selective adsorption of target metal ions. The TiO2-SiO2 outer protective layer acts as a physical barrier, pre-intercepting larger colloidal particles and mechanical impurities in the waste liquid, effectively preventing the internal, delicate mesoporous adsorption layer from becoming clogged, thus ensuring the stability and throughput of the packing material during long-term operation in complex waste liquids. This synergistic design of "internal adsorption and external protection" solves the problem of traditional packing materials being "easy to clog and easy to deactivate."

[0009] In addition, the magnetic Fe3O4 core allows the packing material to be quickly separated and recovered using an external magnetic field.

[0010] Furthermore, it includes the following raw materials in parts by weight:

[0011] 10-20 parts of magnetic Fe3O4 nanoparticles for forming the magnetic Fe3O4 core; 30-50 parts of silica gel, 5-15 parts of activated carbon, 5-15 parts of 3-aminopropyltriethoxysilane, and 3-10 parts of mercaptoacetic acid for forming the mesoporous silica gel adsorption layer; 5-10 parts of nano-alumina, 5-10 parts of diatomaceous earth, 3-8 parts of tetrabutyl titanate, and 2-5 parts of tetraethyl orthosilicate for forming the TiO2-SiO2 outer protective layer.

[0012] Furthermore, the weight ratio of the silica gel to the activated carbon is (3-5):1.

[0013] By employing the above technical solution, the weight ratio of silica gel to activated carbon is limited. Silica gel primarily provides a regular mesoporous structure and mechanical framework, while activated carbon contributes additional specific surface area and surface functional groups. When the ratio is maintained at (3-5):1, it ensures that the packing material as a whole has sufficient structural strength and regular mesoporous channels to facilitate the grafting of functional groups and the diffusion and mass transfer of metal ions, while also fully utilizing the adsorption characteristics of activated carbon as a supplement. This ratio range is crucial for balancing structural stability and adsorption capacity; too low a ratio may lead to a loose structure, while too high a ratio may weaken the synergistic effect of activated carbon.

[0014] Furthermore, the molar ratio of 3-aminopropyltriethoxysilane to mercaptoacetic acid is 1:(0.8-1.2).

[0015] By employing the above technical solution, the key molar ratio of the two functionalized modifiers is defined. The amino (-NH2) and mercapto (-SH) groups affect Cu... 2+ Zn 2+Both exhibit coordination ability, but their binding strength and selectivity differ slightly. Maintaining a molar ratio of 3-aminopropyltriethoxysilane to mercaptoacetic acid at 1:(0.8-1.2) implies that the number of amino and mercapto functional groups is similar. This ratio allows the two groups to achieve optimal synergistic states on the adsorption layer surface, potentially forming a mixed coordination mode. This enhances the overall adsorption capacity, selectivity, and binding strength for target metal ions, avoiding site waste or adsorption performance imbalance caused by an excess of a single group.

[0016] Furthermore, the mesoporous silica adsorption layer has an average pore size of 2-10 nm and a specific surface area of ​​400-800 m². 2 / g.

[0017] By employing the above technical solution, the core physical parameters of the mesoporous adsorption layer are defined. The average pore size of 2-10 nm falls within the typical mesoporous range, and its size is larger than the diameter of common hydrated metal ions, ensuring that ions can diffuse smoothly to the adsorption sites inside the pores. Simultaneously, it exhibits a certain size exclusion effect on larger organic molecules, improving selectivity. The specific surface area is as high as 400-800 m². 2 The / g parameter provides a large surface area for grafting numerous amino and thiol functional groups, ensuring the high adsorption capacity of the filler. These two parameters together define the "doorway, multi-chamber" microstructure necessary for efficient adsorption.

[0018] Furthermore, the TiO2-SiO2 outer protective layer has a through-hole structure with an average pore size of 50-200 nm.

[0019] By adopting the above technical solution, the pore structure characteristics of the outer protective layer are defined. The through-pore structure with an average pore size of 50-200 nm falls into the macroporous category. This structure firstly acts as a "sieve," allowing waste liquid to pass through while trapping or dispersing larger suspended solids, colloidal particles, and other impurities within the pores, preventing them from penetrating and clogging the finer mesoporous adsorption layer inside. Secondly, the through-pore structure ensures low fluid resistance and low pressure drop, which is beneficial for the continuous and stable operation of industrial plants. This structure directly reflects the packing material's excellent anti-fouling and anti-clogging capabilities.

[0020] Secondly, this application provides a method for preparing a solid-phase extraction packing for removing metal ions from waste lubricant in steel cord, using the following technical solution:

[0021] A method for preparing a solid-phase extraction packing for removing metal ions from waste lubricant in steel cord includes the following steps:

[0022] S1. Formation of a magnetic core:

[0023] Magnetic Fe3O4 nanoparticles were prepared to serve as magnetic cores;

[0024] S2. Constructing a mesoporous adsorption layer:

[0025] Using the magnetic core obtained from S1 as the core, silica gel, activated carbon, 3-aminopropyltriethoxysilane and mercaptoacetic acid are co-condensed on its surface by sol-gel method to form a mesoporous silica gel adsorption layer bonded with amino and mercapto bifunctional groups.

[0026] S3. Construct an outer protective layer:

[0027] On the surface of the particles with adsorption layer obtained in S2, tetrabutyl titanate and tetraethyl orthosilicate are hydrolyzed and condensed, and nano-alumina and diatomaceous earth are added to form a composite TiO2-SiO2 gel layer, which is then cured and calcined to obtain the solid phase extraction filler.

[0028] By employing the above technical solution, the magnetic core prepared in step S1 forms the basis for subsequent layer-by-layer assembly. Step S2, through sol-gel co-condensation, achieves in-situ growth of a mesoporous silica layer on the surface of the magnetic core, simultaneously chemically bonding amino and thiol groups to the pore surface, ensuring the stability and high-density distribution of functional groups. Step S3 constructs an outer protective layer through hydrolysis-condensation, incorporating nano-reinforcing phases (alumina, diatomaceous earth) within it, and finally stabilizes the overall structure through curing and calcination. This method is logically clear and highly operable.

[0029] Furthermore, in S2, the co-condensation reaction is carried out in the presence of the template agent hexadecyltrimethylammonium bromide, at a reaction temperature of 60-80°C, and for a reaction time of 6-12 hours.

[0030] The use of hexadecyltrimethylammonium bromide as a template agent, based on the above technical solution, is a key technology for forming ordered or disordered mesoporous structures. This template agent is removed by calcination after the reaction, leaving the desired mesoporous spaces. Controlling the reaction temperature at 60-80℃ and the reaction time at 6-12 hours provides mild and sufficient conditions for the simultaneous and uniform hydrolysis and condensation of the silicon source and the effective grafting of functionalized silanes, thereby forming a high-quality adsorption layer with a well-developed pore structure and uniformly distributed functional groups.

[0031] Furthermore, in S3, the curing and calcination is a gradient calcination, specifically: first aging at 60-100℃, then calcining at 350-500℃ for 2-5 hours at a rate of 1-5℃ / min, and holding at 250-300℃ for 0.5-1 hours.

[0032] By adopting the above technical solution, aging at 60-100℃ helps the gel network to initially solidify and slowly remove solvent, preventing cracking. Subsequent slow temperature ramp-up at 1-5℃ / min, especially setting the temperature range of 250-300℃ and holding for 0.5-1 hour, has multiple benefits: First, it allows the hexadecyltrimethylammonium bromide template agent to fully and slowly decompose and burn within this temperature range, avoiding rapid gas production that could cause the pore structure to collapse, thus forming interconnected macropores; second, it promotes the bonding between the TiO2-SiO2 network and its interface with nano-alumina and diatomaceous earth, enhancing the mechanical strength of the outer protective layer.

[0033] Thirdly, this application provides an application of solid-phase extraction packing material in the regeneration treatment of waste lubricant from steel cord drawing.

[0034] In summary, this application has the following beneficial effects:

[0035] High adsorption capacity and high selectivity: The filler has a well-developed mesoporous structure, high specific surface area, and is bonded with amino and thiol bifunctional groups, which enhances its adsorption capacity for Cu. 2+ Zn 2+ It exhibits high adsorption capacity and high selectivity.

[0036] Excellent anti-clogging and operational stability: The TiO2-SiO2 outer protective layer has a through-pore structure, which can effectively intercept impurities and protect the internal adsorption layer. The example showed a low flux decline rate (3.5%-5.1%) after continuous operation, which is far better than the control sample without a protective layer. Detailed Implementation

[0037] The present application will be further described in detail below with reference to the embodiments.

[0038] Example of raw material and intermediate preparation

[0039] raw material

[0040] It should be noted that: in the following examples, unless otherwise specified, the conditions shall be in accordance with conventional conditions or the manufacturer's recommended conditions; and the raw materials used in the following examples, unless otherwise specified, shall be from commercially available sources.

[0041] Silica gel, particle size 100-200 mesh, specific surface area 300 m² 2 / g;

[0042] Activated carbon powder, particle size 200 mesh, specific surface area 1000 m² 2 / g;

[0043] Nano-alumina, with a particle size of 20-30 nm;

[0044] Diatomaceous earth, refined, 400 mesh particle size.

[0045] Example

[0046] Examples 1-3

[0047] A solid-phase extraction packing for removing metal ions from waste lubricant in steel cord, the preparation method of which is as follows:

[0048] S1. Formation of a magnetic core:

[0049] Solution preparation:

[0050] Weigh out ferric chloride hexahydrate and ferrous chloride tetrahydrate, according to Fe 3+ Fe 2+ A mixed iron salt solution was obtained by dissolving iron salts in deionized water that had been deoxygenated by nitrogen gas at a solid-liquid ratio of 1 g / 11 mL with a molar ratio of 2:1.

[0051] Prepare a 25 wt% ammonia solution as a precipitant;

[0052] Precipitation reaction:

[0053] The iron salt solution was placed in a three-necked flask, stirred and heated to 60°C in a water bath under nitrogen protection. While stirring vigorously, the precipitant preheated to the same temperature was rapidly added dropwise to the iron salt solution until the pH of the system reached 10.

[0054] At this point, the solution quickly turns black, indicating that Fe3O4 has begun to form. Continue to stir the reaction at this temperature for 45 minutes to ensure the reaction is complete and the grains grow.

[0055] Separation and washing:

[0056] After the reaction was completed, the heat source was removed and the container was cooled to room temperature under continuous nitrogen purging. The generated black Fe3O4 particles were adsorbed onto the bottom of the container using an external magnet. The supernatant was discarded and the container was washed four times alternately with deionized water and anhydrous ethanol until the washing solution was neutral and free of chloride ions (detected with AgNO3 solution).

[0057] The washed black magnetic mud was redispersed in anhydrous ethanol to form a stable magnetic Fe3O4 nanoparticle ethanol sol with a solid content of 15wt%, which was set aside for later use. This ethanol sol can be directly used for the next step of core-shell construction.

[0058] S2. Constructing a mesoporous adsorption layer:

[0059] According to Table 1, the magnetic Fe3O4 nanoparticle ethanol sol obtained in S1 (based on the content of magnetic Fe3O4 nanoparticles, for example, if the amount of magnetic Fe3O4 nanoparticles used in Example 1 is 10 kg, then 66.7 kg of magnetic Fe3O4 nanoparticle ethanol sol is taken), silica gel, activated carbon powder and hexadecyltrimethylammonium bromide are added in sequence, and dispersed in a 60°C water bath, under nitrogen protection and stirring at 400 rpm for 1 hour to form a uniform slurry;

[0060] First step functionalization (introduction of amino groups): 3-aminopropyltriethoxysilane was slowly added dropwise to the above slurry. After the addition was complete, the system was heated to 70°C and reacted for 8 hours under reflux, nitrogen protection and stirring.

[0061] The second step is functionalization (introduction of thiol groups): keeping the system conditions unchanged, slowly add mercaptoacetic acid to the reaction solution and continue the reaction at 70°C for 3 hours;

[0062] Intermediate product processing: After the reaction is completed, heating is stopped, and the product is allowed to cool naturally. The solid product is separated by a magnet, washed three times with ethanol, and dried in a vacuum drying oven at 60°C for 6 hours to obtain intermediate particles with a magnetic core-mesoporous adsorption layer.

[0063] S3. Construct an outer protective layer:

[0064] Preparation of the outer protective layer sol: According to the ratio in Table 1, tetrabutyl titanate and tetraethyl orthosilicate were mixed and dissolved in anhydrous ethanol at a solid-liquid ratio of 1 g / 6.5 mL, and magnetically stirred until homogeneous to obtain reaction solution one; nano-alumina and diatomaceous earth were mixed and dispersed in ethanol at a solid-liquid ratio of 1 g / 4 mL, and ultrasonicated for 15 minutes to obtain reaction solution two. Reaction solution one and reaction solution two were mixed, and the pH was adjusted to 3-4 with dilute nitric acid. The mixture was stirred at room temperature for 2 hours to perform pre-hydrolysis and form a stable composite sol.

[0065] Coating and molding: The intermediate particles obtained in S2 are added to the above composite sol and stirred at 200 rpm for 4 hours to ensure that the particle surface is fully wetted and coated by the sol. The slurry is then fed into a spray dryer with an inlet temperature of 180℃, an outlet temperature of 90℃, and a feed rate of 10 mL / min to obtain microspherical precursors.

[0066] Gradient curing and calcination: The microspheres obtained by spray drying are placed in an alumina crucible and then placed in a programmable temperature-controlled muffle furnace.

[0067] First stage (aging): Increase the temperature from room temperature to 80°C at a rate of 2°C / min and keep it at that temperature for 12 hours to completely remove residual solvents and moisture;

[0068] The second stage (decomposition of template agent and formation of channels): the temperature is increased to 280℃ at 3℃ / min and held for 1 hour to allow hexadecyltrimethylammonium bromide to decompose slowly and completely, forming through channels;

[0069] The third stage (structural densification): continue to heat to 400℃ at 3℃ / min and hold for 3 hours to make the TiO2-SiO2 network completely condense and firmly bond with nano-alumina and diatomaceous earth.

[0070] Cooling: After the program ends, turn off the power and allow the furnace to cool naturally to room temperature;

[0071] Sieving: The calcined particles are passed through a standard sieve to collect particles of 0.5-1.0 mm to obtain solid phase extraction packing.

[0072] Table 1 Raw material ratio table for Examples 1-3 / kg

[0073]

[0074] Example 4

[0075] Unlike Example 2, in Example 4 the weight ratio of silica gel to activated carbon is 3:1.

[0076] Example 5

[0077] Unlike Example 2, in Example 5 the weight ratio of silica gel to activated carbon is 5:1.

[0078] Example 6

[0079] Unlike Example 2, in Example 6 the total amount of 3-aminopropyltriethoxysilane and mercaptoacetic acid is the same as in Example 2, but the molar ratio of 3-aminopropyltriethoxysilane to mercaptoacetic acid is 1:0.8.

[0080] Example 7

[0081] Unlike Example 2, in Example 7 the total amount of 3-aminopropyltriethoxysilane and mercaptoacetic acid is the same as in Example 2, but the molar ratio of 3-aminopropyltriethoxysilane to mercaptoacetic acid is 1:1.

[0082] Example 8

[0083] Unlike Example 2, in Example 8 the total amount of 3-aminopropyltriethoxysilane and mercaptoacetic acid is the same as in Example 2, but the molar ratio of 3-aminopropyltriethoxysilane to mercaptoacetic acid is 1:1.2.

[0084] Comparative Example

[0085] Comparative Example 1

[0086] Unlike Example 1, in Comparative Example 1, all raw materials were mixed, ground, and extruded with polyvinyl alcohol binder in one go, and then calcined and sieved according to the same procedure to obtain uniform mixed particles without core-shell structure; wherein the amount of polyvinyl alcohol binder used was 4% of the total weight of other raw materials, and the polyvinyl alcohol binder was prepared as a 5 wt% aqueous solution for use.

[0087] Comparative Example 2

[0088] Unlike Example 1, Comparative Example 2 omits step S1 and starts directly from S2, using a non-magnetic silica gel / activated carbon mixture as the core for subsequent coating.

[0089] Comparative Example 3

[0090] Unlike Example 1, Comparative Example 3 omits the step of constructing the outer protective layer in S3. After the adsorption layer is constructed in S2, the particles are directly solidified and calcined to obtain a double-shell filler with only Fe3O4 core and adsorption layer.

[0091] Comparative Example 4

[0092] Unlike Example 1, in Comparative Example 4, thioglycolic acid was replaced with an equal amount of 3-aminopropyltriethoxysilane.

[0093] Performance testing

[0094] The average pore size of the mesoporous adsorption layer was determined according to GB / T 21650.2-2008, the specific surface area of ​​the mesoporous adsorption layer was determined according to GB / T 19587-2017, and the average pore size of the through-hole structure of the outer protective layer was determined according to GB / T 21650.1-2008. The pore connectivity was observed by scanning electron microscopy (SEM) cross-section. The results are shown in Table 2.

[0095] Table 2. Test results of the physicochemical properties of the packing material

[0096]

[0097] The waste liquid treatment capacity of the packing material in the examples and comparative examples was tested, and the test results are shown in Table 3:

[0098] Cu 2+ Adsorption capacity: Referring to GB / T 39291-2020 "Determination of Copper in Industrial Wastewater", with initial Cu... 2+ The adsorption capacity per unit mass of packing material was calculated after the material was saturated in a simulated waste liquid with a concentration of 100 mg / L.

[0099] Zn 2+ Adsorption capacity: Referring to GB / T 39290-2020 "Determination of Zinc in Industrial Wastewater", the initial Zn...2+ The adsorption capacity per unit mass of packing material was calculated after the material was saturated in a simulated waste liquid with a concentration of 80 mg / L.

[0100] Cu 2+ Removal rate: Taken from waste lubricant (initial Cu) from a steel cord factory 2+ =120 mg / L), solid-liquid ratio 1 g / L, after adsorption for 2 h, the residual concentration was measured and the removal rate was calculated;

[0101] Zn 2+ Removal rate: Taken from waste lubricant (initial Zn) from a steel cord factory 2+ =80 mg / L), solid-liquid ratio 1 g / L, after adsorption for 2 h, the residual concentration was measured and the removal rate was calculated;

[0102] Anti-clogging performance (flux reduction rate): continuous dynamic column experiment, waste liquid flow rate 10 BV / h, flux change rate after 24 h of operation;

[0103] Regeneration performance (adsorption capacity retention after 5 cycles): After adsorption saturation, regeneration was achieved by elution with 0.5 mol / L HCl, repeated 5 times. Calculate Cu. 2+ Adsorption capacity retention rate;

[0104] Selectivity coefficient (Cu / Zn vs Ca / Mg): For preparation of Cu-containing... 2+ Zn 2+ Ca 2+ Mg 2+ A mixed solution of each ion at 50 mg / L (C0) was prepared. A certain mass (m, g) of the packing material was placed in a known volume (V, L) of the above mixed solution, and the mixture was shaken at a constant temperature until adsorption equilibrium was reached. The concentrations of each ion in the solution after equilibrium were determined using ICP-OES. e (mg / L), calculation formula:

[0105] Allocation coefficient: ;

[0106] Selectivity coefficient: , .

[0107] Table 3 Performance Test Results

[0108]

[0109] As can be seen from Tables 2 and 3, Example 1 has a regular outer protective layer of mesopores and macropores, while Comparative Example 1 has a disordered structure. This directly leads to the Cu content of Example 1 being lower. 2+ The adsorption capacity and selectivity coefficients were much higher than those of Comparative Example 1, indicating that the core-shell structure is the decisive factor in forming regular mesopores and achieving high adsorption capacity and high selectivity.

[0110] As can be seen from Tables 2 and 3, Example 2 has a through-hole outer protective layer, while Comparative Example 3 cannot form an effective protective layer. This directly leads to the Cu content of Example 2 being lower when treating real waste liquid. 2+ The removal rate and anti-clogging performance (flux reduction rate) were significantly better than those of Comparative Example 3, indicating that the TiO2-SiO2 outer protective layer is the core of ensuring the efficient and stable operation of the packing in complex waste liquid.

[0111] As can be seen from Table 3, the selectivity coefficient and adsorption capacity retention rate after 5 cycles of Example 7 are both higher than those of Comparative Example 4. This indicates that the synergistic effect of the amino and thiol bifunctional groups is the key to achieving high selectivity and excellent regeneration performance.

[0112] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A solid-phase extraction packing for removing metal ions from waste lubricant in steel cord, characterized in that, It is a composite particle with a core-shell structure, including a magnetic Fe3O4 core, a mesoporous silica adsorption layer covering the core, and a TiO2-SiO2 outer protective layer covering the adsorption layer; the inner surface of the pores of the mesoporous silica adsorption layer is bonded with amino and thiol bifunctional groups. It comprises the following raw materials in parts by weight: 10-20 parts of magnetic Fe3O4 nanoparticles for forming the magnetic Fe3O4 core; 30-50 parts of silica gel, 5-15 parts of activated carbon, 5-15 parts of 3-aminopropyltriethoxysilane, and 3-10 parts of mercaptoacetic acid for forming the mesoporous silica gel adsorption layer; 5-10 parts of nano-alumina, 5-10 parts of diatomaceous earth, 3-8 parts of tetrabutyl titanate, and 2-5 parts of tetraethyl orthosilicate for forming the TiO2-SiO2 outer protective layer.

2. The solid-phase extraction packing material for removing metal ions from waste lubricant in steel cord according to claim 1, characterized in that, The weight ratio of the silica gel to the activated carbon is (3-5):

1.

3. The solid-phase extraction packing material for removing metal ions from waste lubricant in steel cord according to claim 1, characterized in that, The molar ratio of 3-aminopropyltriethoxysilane to mercaptoacetic acid is 1:(0.8-1.2).

4. The solid-phase extraction packing material for removing metal ions from waste lubricant in steel cord according to claim 1, characterized in that, The mesoporous silica adsorption layer has an average pore size of 2-10 nm and a specific surface area of ​​400-800 m². 2 / g.

5. The solid-phase extraction packing material for removing metal ions from waste lubricant in steel cord according to claim 1, characterized in that, The TiO2-SiO2 outer protective layer has a through-hole structure with an average pore size of 50-200 nm.

6. A method for preparing a solid-phase extraction packing material for removing metal ions from waste lubricant in steel cord as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Formation of a magnetic core: Magnetic Fe3O4 nanoparticles were prepared to serve as magnetic cores; S2. Constructing a mesoporous adsorption layer: Using the magnetic core obtained from S1 as the core, silica gel, activated carbon, 3-aminopropyltriethoxysilane and mercaptoacetic acid are co-condensed on its surface by sol-gel method to form a mesoporous silica gel adsorption layer bonded with amino and mercapto bifunctional groups. S3. Construct an outer protective layer: On the surface of the particles with adsorption layer obtained in S2, tetrabutyl titanate and tetraethyl orthosilicate are hydrolyzed and condensed, and nano-alumina and diatomaceous earth are added to form a composite TiO2-SiO2 gel layer, which is then cured and calcined to obtain the solid phase extraction filler.

7. The method for preparing a solid-phase extraction packing for removing metal ions from waste lubricant in steel cord according to claim 6, characterized in that, In S2, the co-condensation reaction is carried out in the presence of the template agent hexadecyltrimethylammonium bromide at a reaction temperature of 60-80°C for 6-12 hours.

8. The method for preparing a solid-phase extraction packing for removing metal ions from waste lubricant in steel cord according to claim 6, characterized in that, In S3, the curing and calcination is a gradient calcination, specifically: first aging at 60-100℃, then calcining at 350-500℃ for 2-5 hours at a rate of 1-5℃ / min, and holding at 250-300℃ for 0.5-1 hours.

9. The application of a solid-phase extraction filler as described in any one of claims 1-5 in the regeneration treatment of waste lubricant from steel cord drawing.

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