Adsorbent for regeneration treatment of waste lubricating oil and preparation method thereof

Abstract

The invention relates to the technical field of regeneration treatment of lubricating oil, in particular to an adsorbent for regeneration treatment of waste lubricating oil and a preparation method of the adsorbent. The adsorbent can effectively remove free water, free water, acid value, solid particles and the like in the waste lubricating oil, and the regeneration quality and the repeated utilization rate of the waste lubricating oil are improved. The adsorbent is formed by compounding an organic metal framework material prepared from p-phenylene diisocyanate and 3-chloropropyltrimethoxysilane. The invention further discloses a preparation method of the adsorbent. The adsorbent disclosed by the invention has extremely strong adsorption capacity on S, P and K elements in the waste lubricating oil, meanwhile, the solid particle purification effect is outstanding, the recovery rate is high, the preparation process is simple, the conditions are mild, the implementation is easy, the production efficiency is high, batch preparation is easy, the regeneration treatment efficiency of the waste lubricating oil is favorably improved, and the production cost and pollution emission are reduced.

Description

Technical Field

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

[0002] As an industrial base oil and additive, lubricating oil is responsible for lubricating machinery and reducing friction. It has multiple functions such as lubrication, auxiliary cooling, rust prevention, cleaning, sealing and buffering. After being injected into the machinery and running for a long time, due to continuous friction and the external environment, its internal molecular structure will change, and the water and solid particle content will gradually increase. Once it exceeds a certain threshold, the lubrication efficiency will decrease, and new oil must be added or replaced. However, the waste lubricating oil cannot be disposed of by burning because of its highly toxic oleic acid and cyclohexane acid components. It can only be landfilled or directly discharged, which undoubtedly brings serious pollution to the environment.

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

[0004] The present invention proposes an adsorbent specially used for waste lubricating oil regeneration and its preparation process. The 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 water, acid value, moisture, and solid particles in waste lubricating oil, and the stability and recovery rate are greatly improved. After being treated with this adsorbent, the regeneration quality of waste lubricating oil is significantly improved, the reuse performance is excellent, the production cost can be effectively reduced, and it has a very broad market prospect. Summary of the invention

[0005] In view of this, the purpose of the present invention is to propose an adsorbent for waste lubricating oil regeneration and a preparation method thereof, so as to solve the problems in the existing waste lubricating oil regeneration technology that the moisture and solid impurities in the waste lubricating oil cannot be effectively removed, the pure regenerated base oil cannot be obtained, and the lubricating oil regeneration quality and reuse rate are low.

[0006] Based on the above purpose, the present invention provides an adsorbent for waste lubricating oil regeneration treatment, wherein the adsorbent is composited by a p-phenylene diisocyanate solution and a modified metal organic framework material, wherein the weight ratio of the modified metal organic framework material to the p-phenylene diisocyanate solution is 0.8-1.2:40-60, and the preparation steps of the modified metal organic framework material are as follows:

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

[0008] (2) adding acetic acid solution to mixed solution A and reacting at 90° C. for 3 h to obtain mixed solution B;

[0009] (3) The product obtained in step (2) is washed with water and ethanol, and then dried to obtain a 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, the weight ratio of the acetic acid aqueous solution to the mixed solution A in step (2) is 3:10.

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

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

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

[0015] The modified metal organic framework material is added into a p-phenylene diisocyanate solution, reacted in a 90-100° C. water bath for 10-12 hours, and then dried to obtain an adsorbent for waste lubricating oil regeneration treatment.

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

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

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

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

[0020] 1. A new type of adsorbent is prepared by using a metal organic framework material containing 3-chloropropyltrimethoxysilane groups modified by 2-aminoterephthalic acid as a precursor. It has a good adsorption capacity for free water, free water, acid value, solid particles, especially S, P, K, etc. in waste lubricating oil.

[0021] 2. The present invention utilizes a metal organic framework material containing 3-chloropropyltrimethoxysilane groups modified by 2-aminoterephthalic acid, and introduces chlorine element into the metal organic framework material, so that the specific surface area of ​​the metal organic framework material in the adsorbent is increased, and its dispersibility in waste oil is better, thereby improving the adsorption capacity of the adsorbent material.

[0022] 3. The present invention utilizes p-phenylene diisocyanate. Since the modified metal organic framework material contains an amino structure, and the urea group generated by the reaction of the amino structure and the phenyl isocyanate group makes the organic metal framework material more stable, thereby avoiding the dissociation of the adsorption material during the adsorption process.

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

[0024] Therefore, the present invention provides a novel, environmentally friendly, and highly adsorbent adsorbent for waste lubricating oil regeneration, which has broad application prospects. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0026] The sources of raw materials used in the specific implementation 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 Denuo Chemical Co., Ltd. Purity: 99%, ammonium acetate was purchased from Beijing Wokai Biotechnology Co., Ltd. Purity: 99%, and acetic acid was purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd. Purity: 99%.

[0028] Example 1: Step 1: 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 were mixed to obtain a mixed solution A;

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

[0030] Step 3: The cooled solution obtained in step 2 is washed three times with 300 ml of water each time and then washed twice with 300 ml of anhydrous ethanol, and the obtained mixture is dried at 80° C. in 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 isocyanate solution, stir and react at 90° C. in a water bath at 500 r / min for 10 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.

[0032] Example 2: Step 1: 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 were mixed to obtain a mixed solution A;

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

[0034] Step 3: The cooled solution obtained in step 2 is washed three times with 150 ml of water each time and then washed twice with 150 ml of anhydrous ethanol, and the obtained mixture is dried at 80° C. in 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 isocyanate solution, stir and react at 95° C. in a water bath at 500 r / min for 11 h, and dry at 80° C. under vacuum for 12 h to obtain an adsorbent for waste lubricating oil regeneration.

[0036] Example 3: Step 1: 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 were mixed to obtain a mixed solution A;

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

[0038] Step 3: The cooled solution obtained in step 2 is washed three times with 330 ml of water each time and then washed twice with 330 ml of anhydrous ethanol, and the obtained mixture is dried at 80° C. in 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 isocyanate solution, stir in a water bath at 100° C. and 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.

[0040] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that the 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 the 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 the modified metal organic framework material is directly used as an adsorbent without being compounded with a p-phenylene isocyanate solution. The specific steps are as follows:

[0043] Step 1: 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 were mixed to obtain a mixed solution A;

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

[0045] Step 3: The cooled solution obtained in step 2 is washed three times with 150 ml of water each time and then washed twice with 150 ml of anhydrous ethanol, and the obtained mixture is dried at 80° C. in vacuum for 12 h to obtain a modified metal organic framework material, which is an adsorbent for waste lubricating oil regeneration treatment;

[0046] Performance Testing

[0047] In order 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 tested for performance, as follows: 100 mL of commercially available waste lubricating oil was purchased from an abandoned automobile repair factory in Bao'an District, Shenzhen, and its heavy metal content (containing 0.2000 mg / LS, 0.3500 mg / LP, 20 mg / LK, 450 mg / L solid particles, 3.77% water content, and 770 mg / L total acid value) was detected. When the adsorbent was added in an amount of 1.5 g / L, the removal rate of S, P, and K elements in the waste lubricating oil and the removal rate of solid particles were detected, as shown in Table 1, respectively.

[0048] Table 1 Performance test results

[0049] sample S residual rate / % P residual rate / % K residual rate / % Solid matter residue rate / % 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 the preparation method of the waste lubricating oil regeneration adsorbent of the present invention has a strong purification effect on S, P, and K elements in the waste lubricating oil, and has a good removal rate for solid residues, moisture and acid value.

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

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

[0053] It can be seen from Example 2 and Comparative Example 3 in Table 1 that the addition of p-phenylene isocyanate to the adsorbent has a significant improvement in the adsorption performance. This may be because the isocyanate group in p-phenylene isocyanate has a 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 thus improving the adsorption capacity. At the same time, the isocyanate group has a high chemical activity. During the adsorption process, p-phenylene isocyanate can react chemically with the active group of the adsorbed substance, thereby achieving chemical adsorption.

[0054] Further, in order to test the stability and recovery rate of the adsorbent, the following tests were performed on Examples 1-3 and Comparative Examples 1-3, respectively. Specifically, 10 g of adsorbent was taken from Examples 1-3 and Comparative Examples 1-3 for ten batches of 1 L of waste lubricating oil (purchased from an abandoned automobile repair factory in Bao'an District, Shenzhen), respectively, and then the waste lubricating oil was treated and recovered. After washing with an organic solvent and drying, the residual mass and the cleanliness of each of the ten batches were measured as shown in Table 2:

[0055] Table 2 Stability and recovery rate

[0056]

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

[0058] It can be seen from Example 2 and Comparative Example 1 in Table 2 that the adsorbent for waste lubricating oil regeneration treatment prepared by using tetramethylsilane has better adsorption stability and recovery rate due to the use of 3-chloropropyltrimethoxysilane group. This may be because the chlorine atom in the molecular structure of 3-chloropropyltrimethoxysilane makes the reactivity 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 condensation reactions to form a stable cross-linked network structure, thereby improving the overall stability of the adsorbent, making it relatively stable in a humid environment or aqueous solution system. In addition, the introduction of chlorine atoms improves its tolerance to chemical substances such as acids and alkalis.

[0059] It can be seen from Example 2 and Comparative Example 2 in Table 2 that the adsorbent containing the metal organic framework material prepared with 2-aminoterephthalic acid is better in stability and recovery rate than the adsorbent containing the metal organic framework material prepared with terephthalic acid. This may be because 2-aminoterephthalic acid contains amino and carboxyl groups. When constructing a metal organic framework with metal ions, the amino and carboxyl groups can both serve as coordination groups to coordinate with the metal ions. This multi-dentate coordination method forms a more stable structure between the metal ions and the ligands. Since the MOF structure containing 2-aminoterephthalic acid is more stable, its pore structure and adsorption site integrity can be better maintained during the adsorption-desorption cycle. This means that when used in multiple cycles, its adsorption performance will not be significantly reduced due to structural damage, which is conducive to maintaining a high recovery rate.

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

[0061] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative 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 may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. 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, the weight ratio of the modified metal organic framework material to the p-phenylene diisocyanate solution is 0.8-1.2:40-60, and 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 adsorbent for waste lubricating oil regeneration according to claim 1, characterized in that: The weight ratio of the acetic acid aqueous solution to the mixed solution A in step (2) is 3:

10.

3. The 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 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 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. A method for preparing an adsorbent for waste lubricating oil regeneration according to any one of claims 1 to 5, characterized in that: The following steps are involved: The modified metal organic framework material is added into a p-phenylene diisocyanate solution, reacted in a 90-100° C. water bath for 10-12 hours, and then dried to obtain an adsorbent for waste lubricating oil regeneration treatment.

7. The preparation method according to claim 6, characterized in that: The drying step is vacuum drying at 80°C for 12 h.

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