Sawdust filter element material for engine oil purification and preparation method thereof

Abstract

The invention discloses a sawdust filter element material for engine oil purification and a preparation method thereof, belonging to the technical field of engine oil filter material preparation, and comprising the following steps: firstly pre-treating sawdust with an alkaline sodium sulfite solution, then respectively performing oxidation-acyl chloride, phenol hydroxylation and amination on the pre-treated sawdust to obtain a first / second / third intermediate product, respectively, and finally mixing the first intermediate product with the second intermediate product and the third intermediate product and performing compression molding under hot conditions to obtain the sawdust filter element material; the invention uses sawdust as a raw material, and obtains an engine oil filter element material with good engine oil filtering performance through chemical modification.

Description

Technical Field

[0001] The invention relates to the technical field of engine oil filter material preparation, and in particular to a sawdust filter element material for engine oil purification and a preparation method thereof. Background Art

[0002] In order to reduce the friction resistance between the moving parts of the engine during operation and reduce the wear of the parts, the engine oil needs to be continuously transported to the surface of each moving part to form a lubricating oil film to lubricate the moving parts. As the engine continues to run, the physical and chemical properties of the engine oil decay due to oxidation, thermal decomposition and impurity contamination. Among them, the factors that affect the performance of the engine oil during use are mainly NO x , H 2 S. SO x Gases, oxidation or decomposition of oil in the engine oil and evaporation of light components, disappearance of additives and diluents in the engine oil, carbon deposits generated during operation, metal grinding chips, and solids such as dust in the air. The deterioration process of engine oil can be divided into two categories: (1) The oxidation process of alkanes, cycloalkanes and aromatic hydrocarbons with long side chains. Hydrocarbons are oxidized to peroxides, and then further oxidized to become carboxyl acids, asphalt acids and even carbonized products; (2) The oxidation process experienced by aromatic hydrocarbons with short side chains and aromatic hydrocarbons without side chains. Hydrocarbons are oxidized to peroxides, and then further oxidized to phenols, gums, asphaltene, and semi-tars. There are also many pollutants generated by the reaction, mainly including acids, asphalt gums, organic salts, carbon, etc. In order to ensure the normal operation of the engine, it is usually necessary to purify the engine oil through an oil filter to filter out impurities and improve the quality of the engine oil.

[0003] There are many types of existing oil filters, and many filter materials are used. In addition to the common paper and polymer filter materials, there are also wood chips, metal mesh and other materials. Among them, wood is widely used in the purification field due to its porosity, permeability and adsorption. The production process of oil filter elements based on wood chips is simple, the cost is low, the filtration accuracy is higher than that of paper, and it can absorb the moisture and acidity of online oil, but the filtration resistance is large, the filtration efficiency is low, and it is very easy to fall off. The molding makes the core body large at both ends and the density in the middle is small, which is easy to deform, and does not achieve a good filtration effect. The service life is also short, and it can generally only be used for shunt filtration. Summary of the invention

[0004] In view of the above problems, the present invention provides a sawdust filter element material for oil purification and a preparation method thereof.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A method for preparing a sawdust filter element material for oil purification comprises the following steps:

[0007] (1) Immerse sawdust in a mixed solution of sodium hydroxide and sodium sulfite, heat to 60-80°C and stir to react for 6-12 hours, filter out the sawdust, wash to neutrality, and dry to obtain a pre-treated product;

[0008] (2) oxidizing the pretreatment product with a TEMPO oxidation system to obtain an oxidation product; dispersing the oxidation product in a dimethylformamide solvent, adding thionyl chloride, stirring and reacting at 60-100° C. for 12-24 hours, separating the precipitate after cooling, washing with a dichloromethane solvent, and drying to obtain a first intermediate product;

[0009] (3) dispersing the pre-treatment product in a dimethylformamide solvent, heating to 60-80° C., adding p-hydroxybenzoyl chloride, and reacting with stirring for 1-2 hours. After the reaction is completed, adding deionized water to dilute the reaction system, separating the precipitate, washing with deionized water, and drying to obtain a second intermediate product;

[0010] (4) dispersing the pre-treated product in a dimethylformamide solvent, adding an aminosilane coupling agent, stirring the reaction sufficiently, separating the precipitate, washing with deionized water, and drying to obtain a third intermediate product;

[0011] (5) The first intermediate product is mixed with the second intermediate product and the third intermediate product, and then molded under hot conditions to obtain the wood chip filter element material.

[0012] In some preferred embodiments, the wood chips are from poplar, eucalyptus or birch.

[0013] In some preferred embodiments, the concentration of sodium hydroxide in the mixed solution of step (1) is 1-2 mol / L, and the concentration of sodium sulfite is 0.1-1 mol / L.

[0014] In some preferred embodiments, the oxidation in step (2) comprises the following steps:

[0015] TEMPO and sodium bromide are weighed in proportion and dissolved in water, the pre-treatment product is added, the sodium hypochlorite solution is added after sufficient stirring and mixing, and the mixture is stirred for reaction at room temperature for 2-6 hours, an alkaline solution is added during the reaction to keep the pH of the reaction system at 9-10, an ethanol solvent is added to dilute the reaction system after the reaction is completed, an acidic solution is added to adjust the pH to neutral, the precipitate is separated and washed with deionized water and an ethanol solvent in sequence, and the oxidation product is obtained after drying.

[0016] In some preferred embodiments, the mass ratio of the TEMPO to the sodium bromide and the sodium hypochlorite is (0.1-0.2):1:(0.09-0.15).

[0017] In some preferred embodiments, the mass ratio of the oxidation product to the thionyl chloride in step (2) is 1:(16-20).

[0018] In some preferred embodiments, the mass ratio of the pre-treatment product in step (3) to the p-hydroxybenzoyl chloride is 1:(4-5).

[0019] In some preferred embodiments, the aminosilane coupling agent in step (4) is N-(2-aminoethyl)-3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane, and the mass ratio of the pre-treatment product to the aminosilane coupling agent is 1:(0.1-1).

[0020] In some preferred embodiments, in step (5), the mass ratio of the first intermediate product to the second intermediate product and the third intermediate product is (2-5):1:(0.8-1.2).

[0021] In some preferred embodiments, the sawdust filter element material further comprises a binder, wherein the binder comprises carboxymethyl cellulose and a wood extract, and the method for preparing the wood extract comprises the following steps:

[0022] The sawdust is immersed in a mixed solution of 1,4-dioxane and water, and the reaction is stirred for 12-24 hours under a protective atmosphere. The supernatant is separated by centrifugation, the solvent is evaporated under reduced pressure, and then an acetic acid solution is added to dissolve it. Deionized water is then added to precipitate it, and the precipitate is separated and washed with ether and deionized water in turn, and then dried to obtain the product.

[0023] Another object of the present invention is to provide a sawdust filter element material for oil purification, wherein the sawdust filter element material is prepared according to the aforementioned preparation method.

[0024] The beneficial effects of the present invention are:

[0025] In view of the problems of large filtering resistance, low filtering efficiency and easy deformation in the existing oil purifier using sawdust as filter element, the present invention provides a filter element material for oil purification based on sawdust. The filter element material uses sawdust as raw material, first pre-treats the sawdust with an alkaline sodium sulfite solution, washes and removes part of the lignin and hemicellulose in the sawdust, expands the pore diameter of the sawdust, and then increases its filtering area. Furthermore, by utilizing the abundant hydroxyl groups on the surface of the pre-treated sawdust, the pre-treated sawdust is oxidized and chlorinated, phenol hydroxylated and aminated, respectively, to obtain the first / second / third intermediate products, respectively, and a rich cross-linked network is formed on the surface of the sawdust through the reaction of the chlorinated product with the phenolic hydroxyl group and the amino group. On the one hand, the cross-linked network can improve the molding stability of the filter element, and on the other hand, the cross-linked network further improves the filtering accuracy of the molded filter element; further, the present invention also adds carboxymethyl cellulose and wood extracts including lignin as adhesives of the filter element, thereby further improving the molding stability of the filter element and improving the adsorption performance of oil pollutants. DETAILED DESCRIPTION

[0026] The present invention is further described in conjunction with the following examples.

[0027] Example 1

[0028] A sawdust filter element material for oil purification, the preparation method of which comprises the following steps:

[0029] (1) Immerse sawdust in a mixed solution of sodium hydroxide and sodium sulfite, heat to 70°C and stir to react for 8 hours, filter out the sawdust, wash to neutrality, and dry to obtain a pre-treated product;

[0030] Wherein, the sawdust is poplar wood, and its particle size is 10-50 mesh; the concentration of the sodium hydroxide in the mixed solution is 1.8 mol / L, and the concentration of the sodium sulfite is 0.8 mol / L;

[0031] (2) TEMPO and sodium bromide were weighed at a mass ratio of 0.16:1 and dissolved in water (sodium bromide concentration was 1 g / L), the pretreatment product was added at a material-liquid ratio of 1 g / 100 mL, sodium hypochlorite solution was added after sufficient stirring and mixing, and the reaction was stirred at room temperature for 4 hours. During the reaction, 0.5 mol / L NaOH solution was added to keep the pH of the reaction system at 9-10. After the reaction was completed, ethanol solvent was added to dilute the reaction system, 0.5 mol / L HCl solution was added to adjust the pH to neutral, the precipitate was separated and washed with deionized water and ethanol solvent in turn, and dried to obtain an oxidation product; the oxidation product was dispersed in dimethylformamide solvent, thionyl chloride was added, the reaction was stirred at 80°C for 16 hours, the precipitate was separated after cooling, washed with dichloromethane solvent, and dried to obtain a first intermediate product; wherein the mass ratio of sodium bromide to sodium hypochlorite was 1:0.1, and the mass ratio of the oxidation product to thionyl chloride was 1:18;

[0032] (3) dispersing the pre-treatment product in dimethylformamide solvent to prepare a dispersion with a mass fraction of 10%, heating to 70° C., adding p-hydroxybenzoyl chloride, and stirring to react for 1 hour. After the reaction is completed, adding deionized water to dilute the reaction system, separating the precipitate, washing with deionized water, and drying to obtain a second intermediate product; wherein the mass ratio of the pre-treatment product to the p-hydroxybenzoyl chloride is 1:4.6;

[0033] (4) dispersing the pre-treatment product in a dimethylformamide solvent to prepare a dispersion with a mass fraction of 10%, adding 3-aminopropyltriethoxysilane, stirring the reaction sufficiently, separating the precipitate, washing with deionized water, and drying to obtain a third intermediate product; wherein the mass ratio of the pre-treatment product to the 3-aminopropyltriethoxysilane is 1:0.18;

[0034] (5) The first intermediate product is mixed with the second intermediate product and the third intermediate product, and then molded under hot conditions to obtain the wood chip filter element material; wherein the mass ratio of the first intermediate product to the second intermediate product and the third intermediate product is 3.5:1:1, the hot pressing temperature is 120-130°C, and the hot pressing pressure is 0.5MPa.

[0035] Example 2

[0036] A sawdust filter element material for oil purification, the preparation method of which comprises the following steps:

[0037] (1) Immerse sawdust in a mixed solution of sodium hydroxide and sodium sulfite, heat to 70°C and stir to react for 8 hours, filter out the sawdust, wash to neutrality, and dry to obtain a pre-treated product;

[0038] Wherein, the sawdust is poplar wood, and its particle size is 10-50 mesh; the concentration of the sodium hydroxide in the mixed solution is 1.8 mol / L, and the concentration of the sodium sulfite is 0.8 mol / L;

[0039] (2) TEMPO and sodium bromide were weighed at a mass ratio of 0.16:1 and dissolved in water (sodium bromide concentration was 1 g / L), the pretreatment product was added at a material-liquid ratio of 1 g / 100 mL, sodium hypochlorite solution was added after sufficient stirring and mixing, and the reaction was stirred at room temperature for 4 hours. During the reaction, 0.5 mol / L NaOH solution was added to keep the pH of the reaction system at 9-10. After the reaction was completed, ethanol solvent was added to dilute the reaction system, 0.5 mol / L HCl solution was added to adjust the pH to neutral, the precipitate was separated and washed with deionized water and ethanol solvent in turn, and dried to obtain an oxidation product; the oxidation product was dispersed in dimethylformamide solvent, thionyl chloride was added, the reaction was stirred at 80°C for 16 hours, the precipitate was separated after cooling, washed with dichloromethane solvent, and dried to obtain a first intermediate product; wherein the mass ratio of sodium bromide to sodium hypochlorite was 1:0.1, and the mass ratio of the oxidation product to thionyl chloride was 1:18;

[0040] (3) dispersing the pre-treatment product in dimethylformamide solvent to prepare a dispersion with a mass fraction of 10%, heating to 70° C., adding p-hydroxybenzoyl chloride, and stirring to react for 1 hour. After the reaction is completed, adding deionized water to dilute the reaction system, separating the precipitate, washing with deionized water, and drying to obtain a second intermediate product; wherein the mass ratio of the pre-treatment product to the p-hydroxybenzoyl chloride is 1:4.6;

[0041] (4) dispersing the pre-treatment product in a dimethylformamide solvent to prepare a dispersion with a mass fraction of 10%, adding 3-aminopropyltriethoxysilane, stirring the reaction sufficiently, separating the precipitate, washing with deionized water, and drying to obtain a third intermediate product; wherein the mass ratio of the pre-treatment product to the 3-aminopropyltriethoxysilane is 1:0.18;

[0042] (5) The first intermediate product is mixed with the second intermediate product, the third intermediate product and an adhesive, and then molded under hot conditions to obtain the sawdust filter element material; wherein the adhesive comprises carboxymethyl cellulose and wood extract in a mass ratio of 1:2.4, and the preparation method of the wood extract comprises the following steps:

[0043] The sawdust was immersed in a mixed solution of 1,4-dioxane and water (v / v=96 / 4) at a material-liquid ratio of 1g / 10mL, stirred for reaction for 18h under a protective atmosphere, the supernatant was separated by centrifugation, the solvent was evaporated under reduced pressure, and then an acetic acid aqueous solution (v / v=9 / 1) was added to dissolve, and then deionized water was added to precipitate, the precipitate was separated and washed with ether and deionized water in turn, and dried to obtain;

[0044] The mass ratio of the first intermediate product to the second intermediate product, the third intermediate product and the adhesive is 3.5:1:1:1.2, the hot pressing temperature is 120-130°C, and the hot pressing pressure is 0.5MPa.

[0045] Comparative Example 1

[0046] A sawdust filter element material for oil purification, the preparation method of which comprises the following steps:

[0047] (1) Immerse sawdust in a mixed solution of sodium hydroxide and sodium sulfite, heat to 70°C and stir to react for 8 hours, filter out the sawdust, wash to neutrality, and dry to obtain a pre-treated product;

[0048] Wherein, the sawdust is poplar wood, and its particle size is 10-50 mesh; the concentration of the sodium hydroxide in the mixed solution is 1.8 mol / L, and the concentration of the sodium sulfite is 0.8 mol / L;

[0049] (2) TEMPO and sodium bromide were weighed at a mass ratio of 0.16:1 and dissolved in water (sodium bromide concentration was 1 g / L), the pretreatment product was added at a material-liquid ratio of 1 g / 100 mL, sodium hypochlorite solution was added after sufficient stirring and mixing, and the reaction was stirred at room temperature for 4 hours. During the reaction, 0.5 mol / L NaOH solution was added to keep the pH of the reaction system at 9-10. After the reaction was completed, ethanol solvent was added to dilute the reaction system, 0.5 mol / L HCl solution was added to adjust the pH to neutral, the precipitate was separated and washed with deionized water and ethanol solvent in turn, and dried to obtain an oxidation product; the oxidation product was dispersed in dimethylformamide solvent, thionyl chloride was added, the reaction was stirred at 80°C for 16 hours, the precipitate was separated after cooling, washed with dichloromethane solvent, and dried to obtain a first intermediate product; wherein the mass ratio of sodium bromide to sodium hypochlorite was 1:0.1, and the mass ratio of the oxidation product to thionyl chloride was 1:18;

[0050] (3) dispersing the pre-treatment product in dimethylformamide solvent to prepare a dispersion with a mass fraction of 10%, heating to 70° C., adding p-hydroxybenzoyl chloride, and stirring to react for 1 hour. After the reaction is completed, adding deionized water to dilute the reaction system, separating the precipitate, washing with deionized water, and drying to obtain a second intermediate product; wherein the mass ratio of the pre-treatment product to the p-hydroxybenzoyl chloride is 1:4.6;

[0051] (4) The first intermediate product and the second intermediate product are mixed and then molded under hot conditions to obtain the wood chip filter element material; wherein the mass ratio of the first intermediate product to the second intermediate product is 3.5:1, the hot pressing temperature is 120-130°C, and the hot pressing pressure is 0.5MPa.

[0052] Comparative Example 2

[0053] A sawdust filter element material for oil purification, the preparation method of which comprises the following steps:

[0054] (1) Immerse sawdust in a mixed solution of sodium hydroxide and sodium sulfite, heat to 70°C and stir to react for 8 hours, filter out the sawdust, wash to neutrality, and dry to obtain a pre-treated product;

[0055] Wherein, the sawdust is poplar wood, and its particle size is 10-50 mesh; the concentration of the sodium hydroxide in the mixed solution is 1.8 mol / L, and the concentration of the sodium sulfite is 0.8 mol / L;

[0056] (2) TEMPO and sodium bromide were weighed at a mass ratio of 0.16:1 and dissolved in water (sodium bromide concentration was 1 g / L), the pretreatment product was added at a material-liquid ratio of 1 g / 100 mL, sodium hypochlorite solution was added after sufficient stirring and mixing, and the reaction was stirred at room temperature for 4 hours. During the reaction, 0.5 mol / L NaOH solution was added to keep the pH of the reaction system at 9-10. After the reaction was completed, ethanol solvent was added to dilute the reaction system, 0.5 mol / L HCl solution was added to adjust the pH to neutral, the precipitate was separated and washed with deionized water and ethanol solvent in turn, and dried to obtain an oxidation product; the oxidation product was dispersed in dimethylformamide solvent, thionyl chloride was added, the reaction was stirred at 80°C for 16 hours, the precipitate was separated after cooling, washed with dichloromethane solvent, and dried to obtain a first intermediate product; wherein the mass ratio of sodium bromide to sodium hypochlorite was 1:0.1, and the mass ratio of the oxidation product to thionyl chloride was 1:18;

[0057] (3) dispersing the pre-treatment product in a dimethylformamide solvent to prepare a dispersion with a mass fraction of 10%, adding 3-aminopropyltriethoxysilane, stirring the reaction sufficiently, separating the precipitate, washing with deionized water, and drying to obtain a third intermediate product; wherein the mass ratio of the pre-treatment product to the 3-aminopropyltriethoxysilane is 1:0.18;

[0058] (4) The first intermediate product and the third intermediate product are mixed and then molded under hot conditions to obtain the wood chip filter element material; wherein the mass ratio of the first intermediate product to the third intermediate product is 3.5:1, the hot pressing temperature is 120-130°C, and the hot pressing pressure is 0.5MPa.

[0059] Comparison example

[0060] A sawdust filter element material for oil purification. The filter element material is sawdust, and the sawdust is untreated poplar sawdust with a particle size range of 10-50 meshes.

[0061] Example 3

[0062] A sawdust filter element material for oil purification, the preparation method of which comprises the following steps:

[0063] (1) Immerse sawdust in a mixed solution of sodium hydroxide and sodium sulfite, heat to 60°C and stir to react for 12 hours, filter out the sawdust, wash to neutrality, and dry to obtain a pre-treated product;

[0064] Wherein, the sawdust is eucalyptus, and its particle size is 10-50 mesh; the concentration of the sodium hydroxide in the mixed solution is 1 mol / L, and the concentration of the sodium sulfite is 0.1 mol / L;

[0065] (2) TEMPO and sodium bromide are weighed at a mass ratio of 0.1:1 and dissolved in water (sodium bromide concentration is 1 g / L), the pretreatment product is added at a material-liquid ratio of 1 g / 100 mL, sodium hypochlorite solution is added after sufficient stirring and mixing, and the reaction is stirred at room temperature for 2 hours. During the reaction, 0.5 mol / L NaOH solution is added to keep the pH of the reaction system at 9-10. After the reaction is completed, ethanol solvent is added to dilute the reaction system, 0.5 mol / L HCl solution is added to adjust the pH to neutral, the precipitate is separated and washed with deionized water and ethanol solvent in turn, and dried to obtain an oxidation product; the oxidation product is dispersed in dimethylformamide solvent, thionyl chloride is added, the reaction is stirred at 60°C for 24 hours, the precipitate is separated after cooling, washed with dichloromethane solvent, and dried to obtain a first intermediate product; wherein the mass ratio of sodium bromide to sodium hypochlorite is 1:0.09, and the mass ratio of the oxidation product to thionyl chloride is 1:16;

[0066] (3) dispersing the pre-treatment product in dimethylformamide solvent to prepare a dispersion with a mass fraction of 10%, heating to 80° C., adding p-hydroxybenzoyl chloride, and stirring to react for 1 hour. After the reaction is completed, adding deionized water to dilute the reaction system, separating the precipitate, washing with deionized water, and drying to obtain a second intermediate product; wherein the mass ratio of the pre-treatment product to the p-hydroxybenzoyl chloride is 1:4;

[0067] (4) dispersing the pre-treatment product in a dimethylformamide solvent to prepare a dispersion with a mass fraction of 10%, adding N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, stirring the reaction sufficiently, separating the precipitate, washing with deionized water, and drying to obtain a third intermediate product; wherein the mass ratio of the pre-treatment product to the N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is 1:0.1;

[0068] (5) The first intermediate product is mixed with the second intermediate product, the third intermediate product and an adhesive, and then molded under hot conditions to obtain the sawdust filter element material; wherein the adhesive comprises carboxymethyl cellulose and wood extract in a mass ratio of 1:1.5, and the preparation method of the wood extract comprises the following steps:

[0069] The sawdust was immersed in a mixed solution of 1,4-dioxane and water (v / v=96 / 4) at a material-liquid ratio of 1g / 10mL, stirred for reaction for 12h under a protective atmosphere, the supernatant was separated by centrifugation, the solvent was evaporated under reduced pressure, and then an acetic acid aqueous solution (v / v=9 / 1) was added to dissolve, and then deionized water was added to precipitate, the precipitate was separated and washed with ether and deionized water in turn, and dried to obtain;

[0070] The mass ratio of the first intermediate product to the second intermediate product, the third intermediate product and the adhesive is 2:1:0.8:1, the hot pressing temperature is 120-130°C, and the hot pressing pressure is 0.5MPa.

[0071] Example 4

[0072] A sawdust filter element material for oil purification, the preparation method of which comprises the following steps:

[0073] (1) Immerse sawdust in a mixed solution of sodium hydroxide and sodium sulfite, heat to 80°C and stir to react for 6 hours, filter out the sawdust, wash to neutrality, and dry to obtain a pre-treated product;

[0074] Wherein, the sawdust is birch, and its particle size is 10-50 mesh; the concentration of the sodium hydroxide in the mixed solution is 2 mol / L, and the concentration of the sodium sulfite is 1 mol / L;

[0075] (2) TEMPO and sodium bromide are weighed at a mass ratio of 0.2:1 and dissolved in water (sodium bromide concentration is 1 g / L), the pretreatment product is added at a material-liquid ratio of 1 g / 100 mL, sodium hypochlorite solution is added after sufficient stirring and mixing, and the reaction is stirred at room temperature for 6 hours. During the reaction, 0.5 mol / L NaOH solution is added to keep the pH of the reaction system at 9-10. After the reaction is completed, ethanol solvent is added to dilute the reaction system, 0.5 mol / L HCl solution is added to adjust the pH to neutral, the precipitate is separated and washed with deionized water and ethanol solvent in turn, and dried to obtain an oxidation product; the oxidation product is dispersed in dimethylformamide solvent, thionyl chloride is added, the reaction is stirred at 100°C for 12 hours, the precipitate is separated after cooling, washed with dichloromethane solvent, and dried to obtain a first intermediate product; wherein the mass ratio of sodium bromide to sodium hypochlorite is 1:0.15, and the mass ratio of the oxidation product to thionyl chloride is 1:20;

[0076] (3) dispersing the pre-treatment product in dimethylformamide solvent to prepare a dispersion with a mass fraction of 10%, heating to 60° C., adding p-hydroxybenzoyl chloride, and stirring to react for 2 hours. After the reaction is completed, adding deionized water to dilute the reaction system, separating the precipitate, washing with deionized water, and drying to obtain a second intermediate product; wherein the mass ratio of the pre-treatment product to the p-hydroxybenzoyl chloride is 1:5;

[0077] (4) dispersing the pre-treatment product in a dimethylformamide solvent to prepare a dispersion having a mass fraction of 10%, adding N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, stirring the reaction sufficiently, separating the precipitate, washing with deionized water, and drying to obtain a third intermediate product; wherein the mass ratio of the pre-treatment product to the N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is 1:1;

[0078] (5) The first intermediate product is mixed with the second intermediate product, the third intermediate product and an adhesive, and then molded under hot conditions to obtain the sawdust filter element material; wherein the adhesive comprises carboxymethyl cellulose and wood extract in a mass ratio of 1:1.5, and the preparation method of the wood extract comprises the following steps:

[0079] The sawdust was immersed in a mixed solution of 1,4-dioxane and water (v / v=96 / 4) at a material-liquid ratio of 1g / 10mL, stirred for reaction for 24 hours under a protective atmosphere, the supernatant was separated by centrifugation, the solvent was evaporated under reduced pressure, and then an acetic acid aqueous solution (v / v=9 / 1) was added to dissolve, and then deionized water was added to precipitate, the precipitate was separated and washed with ether and deionized water in turn, and dried to obtain;

[0080] The mass ratio of the first intermediate product to the second intermediate product, the third intermediate product and the adhesive is 5:1:1.2:2.2, the hot pressing temperature is 120-130°C, and the hot pressing pressure is 0.5MPa.

[0081] Experimental example

[0082] Engine oil with a rubber content of 1.75%, an iron content of 65.2 mg / kg, and an aluminum content of 14.5 mg / kg was used as the test oil. The filtration performance of the wood chip filter element materials prepared in Examples 1-4, Comparative Examples 1-2 and the control example was measured. The filter element performance was measured with reference to the industry standard JB / T5089.3-2020. The measurement results are shown in Table 1.

[0083] Table 1 Comparison of filtration performance of various prepared sawdust filter materials

[0084]

[0085] According to the filtration performance measurement of the sawdust filter element material described in Examples 1-4, it can be seen that the sawdust filter element material described in the present invention has a good filtration effect; by comparing the filtration performance of the sawdust filter element material described in Example 1 and Example 2, it can be seen that the sawdust filter element material with the addition of adhesive not only has better molding stability, but also can improve its adsorption performance for engine oil pollutants; according to the comparison between Example 1 and Comparative Example 1, and between Example 1 and Comparative Example 2, it can be seen that the sawdust filter element material without amination or phenolic hydroxylation pre-treatment products has decreased adsorption performance, filtration efficiency and pressure resistance, but is better than the original sawdust that has not been modified by any physical or chemical treatment.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a sawdust filter element material for oil purification, characterized in that: The following steps are involved: (1) Immerse sawdust in a mixed solution of sodium hydroxide and sodium sulfite, heat to 60-80°C and stir to react for 6-12 hours, filter out the sawdust, wash to neutrality, and dry to obtain a pre-treated product; (2) oxidizing the pretreatment product with a TEMPO oxidation system to obtain an oxidation product; dispersing the oxidation product in a dimethylformamide solvent, adding thionyl chloride, stirring and reacting at 60-100° C. for 12-24 hours, separating the precipitate after cooling, washing with a dichloromethane solvent, and drying to obtain a first intermediate product; (3) dispersing the pre-treatment product in a dimethylformamide solvent, heating to 60-80° C., adding p-hydroxybenzoyl chloride, and reacting with stirring for 1-2 hours. After the reaction is completed, adding deionized water to dilute the reaction system, separating the precipitate, washing with deionized water, and drying to obtain a second intermediate product; (4) dispersing the pre-treated product in a dimethylformamide solvent, adding an aminosilane coupling agent, stirring the reaction sufficiently, separating the precipitate, washing with deionized water, and drying to obtain a third intermediate product; (5) The first intermediate product is mixed with the second intermediate product and the third intermediate product, and then molded under hot conditions to obtain the wood chip filter element material.

2. The method for preparing a sawdust filter element material for oil purification according to claim 1, characterized in that: In the mixed solution of step (1), the concentration of sodium hydroxide is 1-2 mol / L, and the concentration of sodium sulfite is 0.1-1 mol / L.

3. The method for preparing a sawdust filter element material for oil purification according to claim 1, characterized in that: The oxidation in step (2) comprises the following steps: TEMPO and sodium bromide are weighed in proportion and dissolved in water, the pre-treatment product is added, the sodium hypochlorite solution is added after sufficient stirring and mixing, and the mixture is stirred for reaction at room temperature for 2-6 hours, an alkaline solution is added during the reaction to keep the pH of the reaction system at 9-10, an ethanol solvent is added to dilute the reaction system after the reaction is completed, an acidic solution is added to adjust the pH to neutral, the precipitate is separated and washed with deionized water and an ethanol solvent in turn, and the oxidation product is obtained after drying.

4. The method for preparing a sawdust filter element material for oil purification according to claim 3, characterized in that: The mass ratio of the TEMPO to the sodium bromide and the sodium hypochlorite is (0.1-0.2):1:(0.09-0.15).

5. The method for preparing a sawdust filter element material for oil purification according to claim 1, characterized in that: The mass ratio of the oxidation product to the thionyl chloride in step (2) is 1:(16-20).

6. The method for preparing a sawdust filter element material for oil purification according to claim 1, characterized in that: The mass ratio of the pre-treatment product in step (3) to the p-hydroxybenzoyl chloride is 1:(4-5).

7. The method for preparing a sawdust filter element material for oil purification according to claim 1, characterized in that: The aminosilane coupling agent in step (4) is N-(2-aminoethyl)-3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane, and the mass ratio of the pre-treatment product to the aminosilane coupling agent is 1:(0.1-1).

8. The method for preparing a sawdust filter element material for oil purification according to claim 1, characterized in that: In step (5), the mass ratio of the first intermediate product to the second intermediate product and the third intermediate product is (2-5):1:(0.8-1.2).

9. The method for preparing a sawdust filter element material for oil purification according to claim 1, characterized in that: The sawdust filter element material further comprises a binder, wherein the binder comprises carboxymethyl cellulose and a wood extract, and the preparation method of the wood extract comprises the following steps: The sawdust is immersed in a mixed solution of 1,4-dioxane and water, and the reaction is stirred for 12-24 hours under a protective atmosphere. The supernatant is separated by centrifugation, the solvent is evaporated under reduced pressure, and then an acetic acid solution is added to dissolve it. Deionized water is then added to precipitate it, and the precipitate is separated and washed with ether and deionized water in turn, and then dried to obtain the product.

10. A sawdust filter element material for oil purification, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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