An adsorbent for the regeneration treatment of waste lubricating oil and a preparation method thereof

Abstract

The present invention relates to the technical field of waste lubricating oil regeneration treatment, and particularly relates to an adsorbent for waste lubricating oil regeneration treatment and a preparation method thereof. The adsorbent can effectively remove free water, bound water, acid value, solid particles, etc. in the waste lubricating oil, and improve the regeneration quality and reuse rate of the waste lubricating oil. The adsorbent is composed of an organometallic framework material prepared from p-phenylene diisocyanate and 3-chloropropyltrimethoxysilane. The adsorbent of the present invention has extremely strong adsorption capacity for S, P, and K elements in the waste lubricating oil, and at the same time has outstanding purification effect on solid particles, high recovery rate, simple preparation process, mild conditions, easy to implement, high production efficiency, easy to batch preparation, which is beneficial to improving the waste lubricating oil regeneration treatment efficiency, reducing production costs and pollution emissions.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating oils, and particularly to an adsorbent for regenerating waste lubricating oils and a preparation method thereof. Background Art

[0002] As an industrial base oil and additive, lubricating oil undertakes the important tasks of lubricating machinery and reducing friction, and has multiple functions such as lubrication, auxiliary cooling, rust prevention, cleaning, sealing, and buffering. After being injected into machinery and operating for a long time, due to continuous friction and the action of the external environment, the molecular structure inside it will change, and the content of moisture and solid particles will gradually increase. Once it exceeds a specific threshold, the lubrication efficiency will decrease, and at this time, new oil needs to be replenished or replaced. The waste lubricating oil is highly toxic due to its oleic acid and naphthenic acid components, and cannot be disposed of by combustion. It can only be landfilled or directly discharged, which undoubtedly causes serious pollution to the environment.

[0003] In view of this dilemma, the research on regenerating lubricating oils has increasingly become a key research direction. Regenerated lubricating oil can not only improve the utilization efficiency of waste oil, reduce production and environmental protection costs, but also reduce the amount of crude oil extraction, achieve the recycling of lubricating oil, and conform to the concept of green development. At present, the lubricating oil regeneration technology mainly includes two major links: waste oil recovery pretreatment and reprocessing. However, the existing waste lubricating oil regeneration technologies mostly adopt methods such as molecular distillation and thin-film evaporation. These methods can only remove the free water and free moisture in the waste oil, and it is difficult to remove the acid value and solid impurities in it, and it is impossible to obtain pure regenerated base oil, resulting in poor quality and low reuse rate of the regenerated lubricating oil, and it is difficult to be widely promoted.

[0004] The present invention provides an adsorbent for regenerating waste lubricating oils and its preparation process. This adsorbent has excellent adsorption performance, especially strong adsorption capacity for S, P, and K elements, and can effectively adsorb impurities such as free water, free moisture, acid value, moisture, and solid particles in waste lubricating oils. Its stability and recovery rate have been greatly improved. After being treated with this adsorbent, the regeneration quality of waste lubricating oil is significantly improved, and its reuse performance is excellent, which can effectively reduce production costs and has extremely broad market prospects. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an adsorbent for regenerating waste lubricating oils and a preparation method thereof, so as to solve the problems in the existing waste lubricating oil regeneration technology that it is impossible to effectively remove the moisture and solid impurities in waste lubricating oils, impossible to obtain pure regenerated base oil, and the regeneration quality and reuse rate of lubricating oil are low.

[0006] For the above purposes, the present invention provides an adsorbent for the regeneration treatment of waste lubricating oil. The adsorbent is composed of a terephthalic diisocyanate solution and a modified metal-organic framework material. The weight ratio of the modified metal-organic framework material to the terephthalic diisocyanate solution is 0.8 - 1.2:40 - 60. The preparation steps of the modified metal-organic framework material are as follows:

[0007] (1) Mix magnesium chloride, 2-aminoterephthalic acid, N,N-dimethylformamide, 3-chloropropyltrimethoxysilane, and ammonium acetate to obtain a mixed solution A;

[0008] (2) Add acetic acid solution to the mixed solution A and react at 90 °C for 3 h to obtain a mixed solution B;

[0009] (3) Wash the product obtained in step (2) with water and ethanol, and then dry it to obtain the modified metal-organic framework material.

[0010] Preferably, in step (1), the weight ratio of magnesium chloride, 2-aminoterephthalic acid, N,N-dimethylformamide, 3-chloropropyltrimethoxysilane, and ammonium acetate is 0.9 - 1.1:0.25 - 0.29:28 - 32:0.18 - 0.22:0.22 - 0.28.

[0011] Preferably, in step (2), the weight ratio of the acetic acid solution to the mixed solution A is 3:10.

[0012] Preferably, in step (2), the molar concentration of the acetic acid solution is 0.5 mol / L.

[0013] Preferably, in step (3), the drying is carried out by vacuum drying at 80 °C for 12 h.

[0014] Furthermore, the present invention also provides a preparation process for the above adsorbent for the regeneration treatment of waste lubricating oil. The specific preparation process is as follows:

[0015] Add the modified metal-organic framework material to the terephthalic diisocyanate solution, react in a water bath at 90 - 100 °C for 10 - 12 h, and then dry it to obtain the adsorbent for the regeneration treatment of waste lubricating oil.

[0016] Preferably, the weight ratio of the modified metal-organic framework material to the terephthalic diisocyanate is 0.8 - 1.2:40 - 60.

[0017] Preferably, the mass fraction of the terephthalic diisocyanate in the terephthalic diisocyanate solution is 5%.

[0018] Preferably, the drying is carried out by vacuum drying at 80 °C for 12 h.

[0019] The present invention provides an adsorbent for the regeneration treatment of waste lubricating oil and a preparation method thereof, and the main advantages are as follows:

[0020] 1. Using a metal-organic framework material modified by 2-aminoterephthalic acid containing 3-chloropropyltrimethoxysilyl groups as a precursor to prepare a novel adsorbent, which has good adsorption capacity for free water, bound water, acid value, solid particles, especially S, P, K, etc. in waste lubricating oil.

[0021] 2. The present invention uses a metal-organic framework material modified by 2-aminoterephthalic acid containing 3-chloropropyltrimethoxysilyl groups, introducing chlorine elements into the metal-organic framework material, increasing the specific surface area of the metal-organic framework material in the adsorbent, and making its dispersibility in waste oil better, improving the adsorption force of the adsorbent material.

[0022] 3. The present invention uses p-phenylene diisocyanate. Since the modified metal-organic framework material contains an amino structure, and the amino structure reacts with the phenyl isocyanate group to form a urea group, the structure of the metal-organic framework material is more stable, avoiding the dissociation of the adsorbent material during the adsorption process.

[0023] 4. The present invention forms the metal-organic framework material by a one-step reaction hydrothermal method through the intermolecular force by mixing magnesium chloride, 2-aminoterephthalic acid, N,N-dimethylformamide, 3-chloropropyltrimethoxysilane and ammonium acetate. The preparation process is simple, the reaction conditions are mild, it is easy to implement, and the reaction process is simple, the production efficiency is high, it is easy to prepare in batches, which is beneficial to the subsequent regeneration treatment of waste lubricating oil.

[0024] Therefore, the present invention provides a novel, environmentally friendly adsorbent with strong adsorption force for the regeneration treatment of waste lubricating oil, which has broad application prospects. Detailed Embodiments

[0025] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further details the present invention in conjunction with specific embodiments.

[0026] The sources of raw materials used in the specific embodiments of the present invention are as follows:

[0027] 3-Chloropropyltrimethoxysilane was purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd. Purity: 98%, anhydrous methanol was purchased from Jiangsu Pulesi Biotechnology Co., Ltd. Purity: 99%, magnesium chloride was purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd. Purity: 99%, 2-aminoterephthalic acid was purchased from Nantong Runfeng Petrochemical Co., Ltd. Purity: 99%, N,N-dimethylformamide was purchased from Shanghai Deno Chemical Co., Ltd. Purity: 99%, ammonium acetate was purchased from Beijing Wokai Biotechnology Co., Ltd. Purity: 99%, acetic acid was purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd. Purity: 99%.

[0028] Example 1: Step 1: Mix 90 g of magnesium chloride, 25 g of 2-aminoterephthalic acid, 2800 g of N,N-dimethylformamide, 18 g of 3-chloropropyltrimethoxysilane and 22 g of ammonium acetate to obtain a mixed solution A;

[0029] Step 2: Add 9.85 Kg of 0.5 mol / L acetic acid solution to the mixed solution A, and stir at 90 °C at 500 r / min for 3 h;

[0030] Step 3: Wash the cooled solution obtained in Step 2 three times with 300 ml of water each time and then twice with 300 ml of anhydrous ethanol. The obtained mixture is dried at 80 °C under vacuum for 12 h to obtain a modified metal-organic framework material;

[0031] Step 4: Mix 8 g of the modified metal-organic framework material obtained in Step 3 with 400 g of a 5% by mass p-phenylene diisocyanate solution, stir and react at 90 °C in a water bath at 500 r / min for 10 h. After the reaction is completed, it is dried at 80 °C under vacuum for 12 h to obtain an adsorbent for waste lubricating oil regeneration treatment.

[0032] Example 2: Step 1: Mix 50 g of magnesium chloride, 13.5 g of 2-aminoterephthalic acid, 1500 g of N,N-dimethylformamide, 10 g of 3-chloropropyltrimethoxysilane and 12.5 g of ammonium acetate to obtain a mixed solution A;

[0033] Step 2: Add 5 Kg of 0.5 mol / L acetic acid solution to the mixed solution A, and stir at 90 °C at 500 r / min for 3 h;

[0034] Step 3: Wash the cooled solution obtained in Step 2 three times with 150 ml of water each time and then twice with 150 ml of anhydrous ethanol. The obtained mixture is dried at 80 °C under vacuum for 12 h to obtain a modified metal-organic framework material;

[0035] Step 4: Mix 5 g of the modified metal-organic framework material obtained in Step 3 with 250 g of a 5% by mass p-phenylene diisocyanate solution, stir and react at 95 °C in a water bath at 500 r / min for 11 h, and after the reaction is completed, dry at 80 °C under vacuum for 12 h to obtain an adsorbent for waste lubricating oil regeneration treatment.

[0036] Example 3: Step 1: Mix 110 g of magnesium chloride, 29 g of 2-aminoterephthalic acid, 3200 g of N,N-dimethylformamide, 22 g of 3-chloropropyltrimethoxysilane, and 28 g of ammonium acetate to obtain a mixed solution A;

[0037] Step 2: Add 11.30 Kg of a 0.5 mol / L acetic acid solution to the mixed solution A, and stir at 90 °C at 500 r / min for 3 h;

[0038] Step 3: Wash the solution obtained in Step 2 after cooling three times with 330 ml of water each time and then twice with 330 ml of absolute ethanol, and dry the resulting mixture at 80 °C under vacuum for 12 h to obtain a modified metal-organic framework material;

[0039] Step 4: Mix 7.5 g of the modified metal-organic framework material obtained in Step 3 with 450 g of a 5% by mass p-phenylene diisocyanate solution, stir and react at 100 °C in a water bath at 500 r / min for 12 h, and after the reaction is completed, dry at 80 °C under vacuum for 12 h to obtain an adsorbent for waste lubricating oil regeneration treatment.

[0040] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that: 3-chloropropyltrimethoxysilane used in Step 1 is replaced by tetramethylsilane.

[0041] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that: 2-aminoterephthalic acid in Step 1 is replaced by terephthalic acid.

[0042] Comparative Example 3: The difference between Comparative Example 3 and Example 2 is that: directly use the modified metal-organic framework material as an adsorbent without compounding with a p-phenylene diisocyanate solution. The specific steps are as follows:

[0043] Step 1: Mix 50 g of magnesium chloride, 13.5 g of 2-aminoterephthalic acid, 1500 g of N,N-dimethylformamide, 10 g of 3-chloropropyltrimethoxysilane, and 12.5 g of ammonium acetate to obtain a mixed solution A;

[0044] Step 2: Add 5 Kg of a 0.5 mol / L acetic acid solution to the mixed solution A, and stir at 90 °C at 500 r / min for 3 h;

[0045] Step 3: Wash the cooled solution obtained in Step 2 three times with 150 ml of water each time and then two times with 150 ml of absolute ethanol. Dry the obtained mixture under vacuum at 80 °C for 12 h to obtain the modified metal-organic framework material, which is the adsorbent for waste lubricating oil regeneration treatment.

[0046] Performance test

[0047] To verify the performance of the adsorbent in the technical solution of the present invention, the adsorbents prepared in Examples 1-3 and Comparative Examples 1-3 were respectively subjected to performance tests, which are specifically as follows: Take 100 mL of commercially available waste lubricating oil, purchased from a certain abandoned automobile repair factory in Bao'an District, Shenzhen, and detect its heavy metal content (containing 0.2000 mg / L S, 0.3500 mg / L P, 20 mg / L K, 450 mg / L solid particles, water content 3.77%, total acid value 770 mg / L). At an adsorbent addition amount of 1.5 g / L, detect the removal rates of S, P, and K elements in the waste lubricating oil and the removal rate of solid particles, as shown in Table 1 respectively.

[0048] Table 1 Performance test results

[0049] Sample Residual rate of S / % Residual rate of P / % Residual rate of K / % Residual rate of solids / % Water content / % Total acid value / (mg / L) Example 1 0.96 0.85 0.80 1.27 0.56 274 Example 2 0.88 0.72 0.63 1.15 0.48 255 Example 3 0.89 0.77 0.69 1.24 0.49 268 Comparative Example 1 6.99 6.12 6.33 3.68 1.23 512 Comparative Example 2 3.78 3.65 3.64 6.32 1.88 553 Comparative Example 3 5.78 4.99 4.87 4.12 1.66 555

[0050] Data analysis: It can be seen from Examples 1-3 in Table 1 that the adsorbent prepared by using the preparation method of the waste lubricating oil regeneration treatment adsorbent of the present invention has a very strong purification effect on S, P, and K elements in the waste lubricating oil, and has good removal rates for solid residue, moisture, and acid value.

[0051] It can be seen from Example 2 and Comparative Example 1 in Table 1 that the present invention uses a material containing 3-chloropropyltrimethoxysilyl groups as a precursor to prepare an adsorbent for waste lubricating oil regeneration treatment, which has a significant effect on improving the adsorption performance of the adsorbent. This may be because chlorine atoms have high reactivity and can specifically interact with various impurity components in the waste lubricating oil, and can make its dispersibility in waste oil better and have better contact with the waste lubricating oil.

[0052] As can be seen from Example 2 and Comparative Example 2 in Table 1, the adsorption effect of the adsorbent prepared from the metal-organic framework material directly using terephthalic acid is not as good as that of the adsorbent prepared from the metal-organic framework material using 2-aminoterephthalic acid. This may be because the coordination between 2-aminoterephthalic acid and metal ions is stronger, which can form a more stable and regular structure, conducive to providing more effective adsorption sites, thereby increasing the adsorption capacity. At the same time, the amino group of 2-aminoterephthalic acid has certain hydrophilicity, which enhances the adsorption ability of the modified metal-organic framework for hydrophilic substances. In contrast, the metal-organic framework formed by terephthalic acid has a relatively more hydrophobic surface, which is not conducive to the adsorption of hydrophilic substances.

[0053] As can be seen from Example 2 and Comparative Example 3 in Table 1, adding p-phenyl isocyanate to the adsorbent has a great improvement on the adsorption performance. This may be because the isocyanate group in p-phenyl isocyanate has high reactivity and can react with the amino group on the surface of the modified metal-organic framework, thereby providing more adsorption sites, increasing the interaction between the adsorbent and the adsorbate, and further improving the adsorption capacity. At the same time, the isocyanate group has high chemical activity. During the adsorption process, p-phenyl isocyanate can react chemically with the active groups of the adsorbed substance, thereby realizing chemical adsorption.

[0054] Furthermore, in order to test the stability and recycling rate of the adsorbent, the following tests were carried out on Examples 1-3 and Comparative Examples 1-3 respectively, specifically as follows: 10 g of adsorbent was taken from Examples 1-3 and Comparative Examples 1-3 respectively for each batch of 1 L of waste lubricating oil, a total of ten batches (purchased from a certain abandoned automobile repair factory in Bao'an District, Shenzhen), and then recycled after treatment. The remaining mass measured after washing with organic solvents and drying and the cleanliness of each batch in the ten batches are shown in Table 2:

[0055] Table 2 Stability and recycling rate

[0056]

[0057] Data analysis: As can be seen from Examples 1-3 in Table 2, the adsorbent prepared by the preparation method of the waste lubricating oil regeneration treatment adsorbent of the present invention has excellent use stability and recovery rate.

[0058] As can be seen from Example 2 and Comparative Example 1 in Table 2, in the present invention, the adsorbent for waste lubricating oil regeneration prepared using 3-chloropropyltrimethoxysilyl groups is better in terms of adsorption stability and recovery rate than that prepared using tetramethylsilane. This may be because the chlorine atoms in the molecular structure of 3-chloropropyltrimethoxysilane make the reaction activity of the silane coupling agent higher. During the hydrolysis process, although it will also react with water, due to the presence of chlorine atoms, the hydrolysis products are more likely to undergo polycondensation reactions to form a stable cross-linked network structure, thereby improving the overall stability of the adsorbent and making its stability relatively better in a humid environment or an aqueous solution system. Secondly, the introduction of chlorine atoms improves its tolerance to chemical substances such as acids and bases.

[0059] As can be seen from Example 2 and Comparative Example 2 in Table 2, the adsorbent of the metal-organic framework material prepared with 2-aminoterephthalic acid is better than the adsorbent of the metal-organic framework material prepared with terephthalic acid in terms of stability and recovery rate. This may be because 2-aminoterephthalic acid contains amino and carboxyl groups. When constructing the metal-organic framework with metal ions, both the amino and carboxyl groups can act as coordination groups to coordinate with metal ions. This multidentate coordination method makes the structure formed between metal ions and ligands more stable. Since the MOF structure containing 2-aminoterephthalic acid is more stable, during the adsorption-desorption cycle process, it can better maintain the integrity of its pore structure and adsorption sites. This means that during multiple cycles of use, its adsorption performance will not decrease significantly due to structural damage, which is beneficial to maintaining a high recovery rate.

[0060] As can be seen from Example 2 and Comparative Example 3 in Table 2, the use of p-phenylene diisocyanate has an obvious effect on improving adsorption stability and recovery rate. This may be because p-phenylene diisocyanate can be combined with the matrix material of the adsorbent through chemical bonds to enhance the overall stability of the adsorbent. The modified metal-organic framework material used in the present invention contains an amino structure, which makes the isocyanate group in p-phenylene diisocyanate act with the amino structure, and further makes the urea group formed by the isocyanate group and the amino structure connected to the metal-organic framework material, improving the structural stability of the metal-organic framework material, reducing the dissociation of the adsorbent during the adsorption process, and increasing the recovery rate of the adsorbent during use.

[0061] Those of ordinary skill in the art should understand that: the discussion of any above embodiment is only exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A method for preparing an adsorbent for waste lubricating oil regeneration, characterized in that: The adsorbent is composited by a p-phenylene diisocyanate solution and a modified metal organic framework material, and specifically comprises the following steps: adding the modified metal organic framework material to the p-phenylene diisocyanate solution, reacting in a 90-100° C. water bath for 10-12 hours, and then vacuum drying at 80° C. for 12 hours to obtain an adsorbent for waste lubricating oil regeneration treatment; The weight ratio of the modified metal organic framework material to the p-phenylene diisocyanate solution is 0.8-1.2:40-60. The preparation steps of the modified metal organic framework material are as follows: (1) mixing magnesium chloride, 2-aminoterephthalic acid, N,N-dimethylformamide, 3-chloropropyltrimethoxysilane and ammonium acetate to obtain a mixed solution A; (2) adding acetic acid solution to mixed solution A and reacting at 90° C. for 3 h to obtain mixed solution B; (3) washing the product obtained in step (2) with water and ethanol, and then drying to obtain a modified metal organic framework material; In step (1), the weight ratio of magnesium chloride, 2-aminoterephthalic acid, N,N-dimethylformamide, 3-chloropropyltrimethoxysilane and ammonium acetate is 0.9-1.1: 0.25-0.29: 28-32: 0.18-0.22: 0.22-0.

28.

2. The method for preparing an adsorbent for waste lubricating oil regeneration according to claim 1, characterized in that: The weight ratio of the acetic acid solution to the mixed solution A in step (2) is 3:

10.

3. The method for preparing an adsorbent for waste lubricating oil regeneration according to claim 1, characterized in that: The molar concentration of the acetic acid solution in step (2) is 0.5 mol / L.

4. The method for preparing an adsorbent for waste lubricating oil regeneration according to claim 1, characterized in that: The drying in step (3) is performed by vacuum drying at 80° C. for 12 h.

5. The method for preparing an adsorbent for waste lubricating oil regeneration according to claim 1, characterized in that: The mass fraction of the p-phenylene diisocyanate solution is 5%.

6. An adsorbent for waste lubricating oil regeneration, prepared by the preparation method according to any one of claims 1 to 5.

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