A metal-modified decolorizing agent and its preparation method and application

Abstract

The present invention discloses a metal-modified decolorizing agent, a preparation method, and an application thereof, belonging to the technical field of regeneration adsorption treatment of electric power oil. The preparation method comprises the following steps: pre-treating a porous matrix material to obtain a pre-treated porous matrix material; immersing the pre-treated porous matrix material in a chloride solution to obtain a process product A; mixing the process product A with an activation reagent to obtain a suspension, filtering the suspension to obtain a process product B, and finally drying the process product B to obtain a metal-modified porous matrix material; placing the metal-modified porous matrix material into a chitosan solution, adding a polyvinyl alcohol solution, and finally filtering, washing, and drying. The metal-modified decolorizing agent provided by the present invention, its preparation method, and application thereof can prevent metal ions loaded on the porous matrix material from falling into degraded oil and contaminating the degraded oil.

Description

Technical Field

[0001] The invention relates to a metal modified decolorizing agent and a preparation method and application thereof, belonging to the technical field of regeneration adsorption treatment of power oil. Background Art

[0002] The oil used in power equipment is a crucial medium for insulation, cooling, and lubrication. However, during use, oil is subject to oxidation from air and high temperatures, as well as the influx of metal particles, moisture, and impurities. This can lead to the formation of colloids, asphaltenes, organic macromolecules, and heterocyclic compounds containing oxygen, sulfur, and nitrogen. These substances deteriorate the insulation properties of power oil, darken its color, and increase the amount of sediment, sludge, and varnish, which can cause equipment failure. Therefore, decolorizing and regenerating degraded power oil is the best option from an economic, environmental, and resource-efficient perspective.

[0003] The adsorption process can eliminate harmful pollutants, improve the color and odor of deteriorated power oil, and restore the performance of the oil. Therefore, adsorption decolorization and regeneration of deteriorated power oil is one of the most effective and feasible methods. Decolorizers are a key factor affecting the decolorization effect of oils and fats. Currently, the commonly used decolorizers for deteriorated oils in my country include activated carbon, diatomaceous earth, kaolin, activated alumina, etc. When porous matrix materials are used for adsorption decolorization, the adsorption capacity is very low and the decolorization effect on deteriorated oils is not obvious. Therefore, the modification of the surface physical structure properties and surface chemical modification of porous matrix materials are of great significance to improving their decolorization performance. The existing technology has investigated the removal effect of transition metal modified silica gel adsorbents on nitrogen compounds in coking diesel. The results show that the adsorbent can reduce the content of nitrogen compounds in oil products and improve the color of oil products. The metal modified decolorizer reported above has the ability to decolorize oil products.

[0004] However, during the decolorization process of degraded oil using the metal-modified porous matrix material, the loaded metal ions will inevitably fall into the degraded oil, contaminating the degraded oil and causing the performance of the degraded oil to deteriorate. Therefore, the decolorization material obtained by simply modifying the porous matrix material cannot be immediately applied in the decolorization process of degraded oil. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a metal-modified decolorizing agent for regeneration of power oil and a preparation method thereof, which can prevent the metal ions loaded on the porous matrix material from falling into the degraded oil, contaminating the degraded oil and causing the performance of the degraded oil to deteriorate.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] In a first aspect, a method for preparing a metal-modified decolorizing agent is provided, comprising the following steps:

[0008] Step a, rinsing the porous matrix material with deionized water and then soaking it in deionized water, and then filtering and drying it to obtain a pretreated porous matrix material;

[0009] Step b, immersing the pretreated porous matrix material in a chloride salt solution, and then filtering, air-drying, roasting and cooling to obtain process product A;

[0010] Step c: Mixing process product A with an activation reagent to obtain a suspension, filtering the suspension to obtain process product B and the filtered activation reagent. Measure the pH of the filtered activation reagent and repeat the activation steps multiple times until the pH reaches a neutral range (specifically, 7-8) to avoid contamination of the activation reagent with acidic or alkaline residues. Finally, drying process product B to obtain a metal-modified porous matrix material.

[0011] Step d: adding the metal-modified porous matrix material into the chitosan solution, stirring for a period of time, then adding the polyvinyl alcohol solution, continuing to stir for a period of time, and finally filtering, washing and drying.

[0012] In step a, the porous matrix material is one of coconut shell crushed activated carbon, coal crushed activated carbon, fruit shell activated carbon and columnar activated carbon.

[0013] In step a, the soaking time is 2 to 6 hours, preferably 4 hours.

[0014] In step b, the immersion time is 18 to 30 hours, preferably 24 hours; the chloride salt solution is one of ZnCl2, FeCl3 and BaCl2 solutions, and the concentration of the chloride salt solution ranges from 1 to 20 wt%, preferably 5 wt% FeCl3 solution; the calcination conditions are: calcination at 260 to 340 ° C for 1 to 4 hours, preferably calcination at 300 ° C for 2 hours.

[0015] In step c, the activation reagent is selected from one of deionized water, ethanol and methanol, preferably ethanol; the mixing time is 8 to 20 hours, the mixing temperature is 25 to 40°C, preferably 10 hours at 25°C; the process product A and the activation reagent are mixed in a mass ratio of 1:1 to 1:5, preferably 1:3, and the mixing method is selected from one of the static method, ultrasonic extraction method and shaking table method, preferably shaking table method.

[0016] In step d, the metal-modified porous matrix material is mixed with a chitosan solution and a polyvinyl alcohol solution in a mass ratio of 1:3 to 5:3, the concentration of the chitosan solution is in the range of 1 to 20 wt%, preferably 5 wt%; the concentration of the polyvinyl alcohol solution is in the range of 1 to 20 wt%, the single stirring time is 1 to 5 h, preferably 3 h, and the stirring temperature is 20 to 40 ° C, preferably 25 ° C.

[0017] In step a, step c and step d, the drying conditions are: drying at 100-140°C for 12-18 h, preferably drying at 120°C for 12 h.

[0018] In a second aspect, a metal-modified decolorizing agent is provided, which is prepared by the method for preparing a metal-modified decolorizing agent for regeneration of electric power oil described in the first aspect.

[0019] In a third aspect, there is provided a use of the metal-modified decolorizing agent described in the second aspect as an adsorbent in deteriorated power oil.

[0020] The mass ratio of metal modified decolorizer to deteriorated power oil is 1~2:4, the adsorption temperature is 60~100 ℃, and the adsorption time is 2~6 h.

[0021] Beneficial Effects of the Invention: The present invention provides a method for preparing a metal-modified decolorizing agent for regenerating power oil. The method involves immersing a pretreated porous substrate in a chloride solution, placing the metal-modified porous substrate in a chitosan solution, and then adding a polyvinyl alcohol solution. By loading the porous substrate with metal and securing it by a wrapping method, the method prevents metal particles from falling off the porous substrate and entering degraded oil, contaminating the degraded oil and degrading its performance. Furthermore, colored substances such as heterocyclic compounds containing oxygen, sulfur, and nitrogen in degraded power oil react with metal ion compounds with empty outer orbitals and small ionic radii, becoming adsorbed on the microporous decolorizing agent of the present invention, thereby enhancing the adsorption efficiency of the adsorbent on colored substances in degraded power oil. DETAILED DESCRIPTION

[0022] The present invention will be further described below. The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] Example 1

[0024] Crushed coal-based activated carbon was rinsed with deionized water, soaked for 4 hours, filtered, and dried at 120°C for 12 hours. 10 g of pretreated activated carbon was immersed in 100 mL of a 5 wt% ZnCl₂ solution for 24 hours, filtered, dried in the shade, and calcined at 300°C for 2 hours. The cooled activated carbon was mixed with ethanol in a 1:3 mass ratio and shaken at 25°C for 10 hours. After activation with ethanol three times, the activated carbon was filtered and dried at 120°C for 12 hours to obtain metal-modified activated carbon. The metal-modified activated carbon was then mixed with a 5 wt% chitosan solution in a 1:3 mass ratio to obtain a suspension, which was stirred at 25°C for 3 hours. Then, 13 wt % polyvinyl alcohol solution was added to the above suspension according to the mass ratio (metal-modified activated carbon: 13 wt % polyvinyl alcohol solution = 1:3), and the mixture was stirred at 25 °C for 3 h. The metal-modified decolorizer was obtained after filtration, washing, and drying.

[0025] Example 2

[0026] Crushed coal-based activated carbon was rinsed with deionized water, soaked for 4 hours, filtered, and dried at 120°C for 12 hours. 10 g of pretreated activated carbon was immersed in 100 mL of a 5 wt% BaCl₂ solution for 24 hours, filtered, dried in the shade, and calcined at 300°C for 2 hours. The cooled activated carbon was mixed with ethanol in a 1:3 mass ratio and shaken at 25°C for 10 hours. After activation with ethanol three times, the activated carbon was filtered and dried at 120°C for 12 hours to obtain metal-modified activated carbon. The metal-modified activated carbon was then mixed with a 5 wt% chitosan solution in a 1:3 mass ratio to obtain a suspension, which was stirred at 25°C for 3 hours. Then, 13 wt % polyvinyl alcohol solution was added to the above suspension according to the mass ratio (metal-modified activated carbon: 13 wt % polyvinyl alcohol solution = 1:3), and the mixture was stirred at 25 °C for 3 h. The metal-modified decolorizer was obtained after filtration, washing, and drying.

[0027] Example 3

[0028] Crushed coal-based activated carbon was rinsed with deionized water, soaked for 4 hours, filtered, and dried at 120°C for 12 hours. 10 g of pretreated activated carbon was immersed in 100 mL of a 5 wt% FeCl₃ solution for 24 hours, filtered, dried in the shade, and calcined at 300°C for 2 hours. The cooled activated carbon was mixed with ethanol in a 1:3 mass ratio and shaken at 25°C for 10 hours. After activation with ethanol three times, the activated carbon was filtered and dried at 120°C for 12 hours to obtain metal-modified activated carbon. The metal-modified activated carbon was then mixed with a 5 wt% chitosan solution in a 1:3 mass ratio to obtain a suspension, which was stirred at 25°C for 3 hours. Then, 13 wt % polyvinyl alcohol solution was added to the above suspension according to the mass ratio (metal-modified porous matrix material: 13 wt % polyvinyl alcohol solution = 1:3), and the mixture was stirred at 25 °C for 3 h. The metal-modified decolorizing agent was obtained after filtration, washing, and drying.

[0029] Example 4

[0030] Crushed coal-based activated carbon was rinsed with deionized water, soaked for 4 hours, filtered, and dried at 120°C for 12 hours. 10 g of pretreated activated carbon was immersed in 100 mL of a 5 wt% FeCl₃ solution for 24 hours, filtered, dried in the shade, and calcined at 300°C for 2 hours. The cooled activated carbon was mixed with deionized water in a 1:3 mass ratio and shaken at 25°C for 10 hours. After activation with deionized water three times, the activated carbon was filtered and dried at 120°C for 12 hours to obtain metal-modified activated carbon. The metal-modified activated carbon was then mixed with a 5 wt% chitosan solution in a 1:3 mass ratio to obtain a suspension, which was stirred at 25°C for 3 hours. Then, 13 wt % polyvinyl alcohol solution was added to the above suspension according to the mass ratio (metal-modified activated carbon: 13 wt % polyvinyl alcohol solution = 1:3), and the mixture was stirred at 25 °C for 3 h. The metal-modified decolorizer was obtained after filtration, washing, and drying.

[0031] Example 5

[0032] Crushed coal-based activated carbon was rinsed with deionized water, soaked for 4 hours, filtered, and dried at 120°C for 12 hours. 10 g of pretreated activated carbon was immersed in 100 mL of a 5 wt% FeCl₃ solution for 24 hours, filtered, dried in the shade, and calcined at 300°C for 2 hours. The cooled activated carbon was mixed with ethanol in a 1:3 mass ratio and shaken at 25°C for 10 hours. After activation with ethanol three times, the activated carbon was filtered and dried at 120°C for 12 hours to obtain metal-modified activated carbon. The metal-modified activated carbon was then mixed with a 5 wt% chitosan solution in a 1:5 mass ratio to obtain a suspension, which was stirred at 25°C for 3 hours. Then, 13 wt % polyvinyl alcohol solution was added to the above suspension according to the mass ratio (metal-modified activated carbon: 13 wt % polyvinyl alcohol solution = 1:5), and the mixture was stirred at 25 °C for 3 h. The metal-modified decolorizer was obtained after filtration, washing, and drying.

[0033] Comparative Example

[0034] Crushed coal-based activated carbon was rinsed with deionized water, soaked for 4 hours, filtered, and dried at 120°C for 12 hours. 10 g of pretreated activated carbon was immersed in 100 mL of a 5 wt% FeCl₃ solution for 24 hours, filtered, dried in the shade, and calcined at 300°C for 2 hours. The cooled activated carbon was mixed with methanol in a 1:3 mass ratio and shaken at 25°C for 10 hours. After activation with methanol three times, the activated carbon was filtered and dried at 120°C for 12 hours to obtain a metal-modified decolorizer.

[0035] Table 1 Decolorization performance of metal modified decolorizers in various examples and comparative examples

[0036]

[0037] Performance Evaluation: 5 g of the metal-modified decolorizer prepared in Examples 1 to 5 and the comparative example was weighed and placed in 15 g of degraded power oil. The mixture was adsorbed at 80°C for 4 hours using a magnetic heating stirrer to ensure full contact between the decolorizer and the oil for optimal adsorption. After adsorption, the oil was filtered while hot, and the sample was subjected to a colorimetric test. The decolorization performance results of the metal-modified decolorizers prepared in the examples and comparative examples are shown in Table 1. As can be seen from Table 1, the metal-modified decolorizers prepared in Examples 1 to 5 of the present invention all achieved high decolorization efficiencies for degraded power oil, exceeding 80%. Furthermore, a comparison of Example 3 with the comparative example shows that the present invention significantly improves the adsorption performance of the metal-modified decolorizer by adding a coating treatment to the metal-modified decolorizer.

[0038] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a metal-modified decolorizing agent, characterized in that: The following steps are involved: Step a, rinsing the porous matrix material with deionized water and then soaking it in deionized water, the porous matrix material being coal-based crushed activated carbon, the soaking time being 4 hours, and then filtering and drying it, drying it at 120° C. for 12 hours to obtain a pretreated porous matrix material; Step b, immersing the pretreated porous matrix material in 100 mL of a 5 wt% FeCl3 solution for 24 h, then filtering and drying in the shade, calcining at 300 °C for 2 h, and cooling to obtain process product A; Step c, mixing the process product A with an activation reagent to obtain a suspension, wherein the process product A and the activation reagent are mixed in a mass ratio of 1:3, the mixing method is a shaking table method, the activation reagent is selected from ethanol, the mixing time is 10 hours, and the mixing temperature is 25°C. The suspension is then filtered to obtain the process product B and the filtered activation reagent, and finally the process product B is dried to obtain a metal-modified porous matrix material, and the drying conditions are: drying at 120°C for 12 hours; Step d, adding the metal-modified porous matrix material to the chitosan solution, stirring for a period of time, then adding the polyvinyl alcohol solution, continuing to stir for a period of time, and finally filtering, washing and drying. The metal-modified porous matrix material is mixed with the chitosan solution and the polyvinyl alcohol solution in a mass ratio of 1:3:3, the chitosan solution concentration is 5wt%; the polyvinyl alcohol solution concentration is 13wt%, the single stirring time is 3 h, and the stirring temperature is 25°C.

2. The method for preparing a metal-modified decolorizing agent according to claim 1, wherein: In step d, the drying conditions are: drying at 100-140°C for 12-18 hours.

3. A metal-modified decolorizing agent for regeneration of power oil, characterized by: The decolorizing agent is prepared by the method for preparing the metal-modified decolorizing agent according to any one of claims 1 to 2.

4. Use of the metal-modified decolorizing agent according to claim 3 as an adsorbent in deteriorated power oil.

5. The use according to claim 4, characterized in that: The mass ratio of metal modified decolorizer to deteriorated power oil is 1~2:4, the adsorption temperature is 60~100 ℃, and the adsorption time is 2~6 h.

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