A loofah-based crosslinked hydrophobic and lipophilic modified oil-absorbing material and its preparation method

Abstract

The present invention discloses a preparation method of a loofah sponge-based crosslinked hydrophobic and lipophilic modified oil-absorbing material, which includes grafting bisphenol dicycloglycidyl ether between internal fibers of a loofah sponge pretreated with an alkali solution to obtain a crosslinked modified loofah sponge; adding a hydrophobic and lipophilic long-chain alkyl compound to the reaction solution after the grafting reaction, and continuously stirring and reacting to obtain a loofah sponge-based crosslinked hydrophobic and lipophilic modified oil-absorbing material. The mass ratio of the alkali solution-pretreated loofah sponge to the long-chain alkyl compound is 1:(0.4-0.8). The present invention also discloses a loofah sponge-based crosslinked hydrophobic and lipophilic modified oil-absorbing material prepared by the preparation method. The oil-absorbing material prepared by the present invention simultaneously has excellent hydrophobic and lipophilic properties and reusability, and the preparation method is simple.

Description

Technical Field

[0001] The present invention relates to the technical field of solid adsorbents, and particularly to a loofah-based crosslinked hydrophobic and lipophilic modified oil-absorbing material and a preparation method thereof. Background Art

[0002] Loofah has a unique spatial structure composed of macroscopic macropores and micropores. Coupled with the characteristics of low cost, renewable utilization, and easy biodegradation, it can be used as a biomass porous oil-absorbing material.

[0003] However, the natural hydrophilic and lipophilic properties of loofah limit its adsorption efficiency and oil-water separation effect, and it is difficult to meet the requirements of efficient oil-water separation in practical applications. Although a variety of low-surface-energy substances have been used to hydrophobically modify loofah at present, most of these hydrophobic substances are only attached to the surface of loofah by physical coating, lacking a firm chemical bond connection, resulting in the easy shedding of the hydrophobic layer during the repeated use process, thus affecting the repeated utilization rate of loofah. In addition, loofah also needs to face the challenges of complex environmental conditions such as changes in acidity and alkalinity and temperature fluctuations in practical applications. The original loofah is prone to degradation or failure under these conditions, thereby reducing its oil-absorbing performance and service life. Therefore, it is particularly important to chemically modify loofah to improve its oil-water separation performance and enhance its durability. However, although the existing chemical modification technologies have improved the performance of loofah to a certain extent, the improvement effect is limited and the modification process is relatively complicated. Summary of the Invention

[0004] Aiming at the deficiencies of the above-mentioned prior art, the present invention provides a preparation method of a loofah-based crosslinked hydrophobic and lipophilic modified oil-absorbing material and a loofah-based crosslinked hydrophobic and lipophilic modified oil-absorbing material prepared by this preparation method, aiming to simply and efficiently chemically modify loofah, and at the same time significantly improve the oil-water separation performance and durability of loofah.

[0005] The technical solution of the present invention is as follows: A preparation method of a loofah-based crosslinked hydrophobic and lipophilic modified oil-absorbing material, comprising the following steps:

[0006] (1) Crosslinking and grafting bisphenol dicycloglycerol ether between the internal fibers of loofah pretreated with alkali solution to obtain crosslinked modified loofah;

[0007] (2) Adding a hydrophobic and lipophilic long-chain alkyl compound to the reaction solution after the crosslinking and grafting reaction in step (1), and continuing to stir and react to obtain a loofah-based crosslinked hydrophobic and lipophilic modified oil-absorbing material, and the mass ratio of the loofah pretreated with alkali solution to the long-chain alkyl compound is 1:(0.4 - 0.8).

[0008] Further, in step (1), the loofah sponge pretreated with alkali solution is added to ethanol, bisphenol dicycloglycidyl ether is added, and an organic acid is added as a catalyst for cross-linking grafting reaction, wherein the mass ratio of the loofah sponge pretreated with alkali solution, bisphenol dicycloglycidyl ether, and organic acid is 1:(0.1~0.3):(0.03~0.07).

[0009] Further, the organic acid is one of formic acid and acetic acid.

[0010] Further, the cross-linking grafting reaction in step (1) is carried out under stirring at 40~60 °C for 6~10 h.

[0011] Further, the hydrophobic and lipophilic long-chain alkyl compound is a hydrophobic and lipophilic epoxy alkane.

[0012] Further, after adding the hydrophobic and lipophilic long-chain alkyl compound in step (2), the reaction is continued under stirring at 40~60 °C for 6~10 h. After the reaction, suction filtration, repeated washing with ethanol, and drying are carried out to obtain the loofah sponge-based cross-linked hydrophobic and lipophilic modified material.

[0013] Further, the alkali solution pretreatment is to soak the loofah sponge in a 2%~15% NaOH aqueous solution, stir and treat it at 60~100 °C for 2~5 h, and then wash it with deionized water until neutral.

[0014] Another technical solution of the present invention is a loofah sponge-based cross-linked hydrophobic and lipophilic modified oil-absorbing material, which is prepared by the preparation method of the loofah sponge-based cross-linked hydrophobic and lipophilic modified oil-absorbing material described above.

[0015] The present invention utilizes the ring-opening reaction of hydroxyl group and epoxy group to firstly realize the cross-linking grafting of bisphenol dicycloglycidyl ether inside the loofah sponge. Cross-linking modification not only further improves the porosity and specific surface area of the loofah sponge, but also introduces a series of lipophilic groups such as benzene ring structure, methylene group, and ether group. More importantly, cross-linking modification significantly enhances the structural stability of the loofah sponge, ensuring that in practical applications, the structure of the loofah sponge can resist external extrusion without being damaged. Subsequently, the present invention uses the new hydroxyl groups generated by the ring-opening reaction as binding sites to covalently graft a large number of hydrophobic and lipophilic long-chain alkyl compounds onto the cross-linked and grafted loofah sponge. This step not only further enriches the hydrophobic and lipophilic groups of the loofah sponge, but also ensures that the hydrophobic and lipophilic substances can be tightly attached to the loofah sponge through the strong connection of covalent bonds, effectively avoiding the problem of shedding during repeated use.

[0016] The advantages of the present invention compared with the prior art are as follows:

[0017] (1) The loofah sponge cross-linked hydrophobic and lipophilic modification method provided by the present invention has simple and clear steps, efficient and convenient operation, and significantly reduces the production cost and time cost.

[0018] (2) The modified loofah sponge prepared by the present invention not only has a rich pore structure, but also has a large number of hydrophobic and lipophilic groups, so it has very excellent oil-water separation ability.

[0019] (3) The modified loofah sponge prepared by the present invention not only has excellent oil-water separation performance, but also improves its durability and environmental adaptability through the dual enhancement of cross-linking modification and covalent hydrophobic and lipophilic modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It shows the variation of the adsorption amount of the loofah sponge-based cross-linked hydrophobic and lipophilic modified oil-absorbing material prepared in Example 1 of the present invention for engine oil with the number of cycles.

[0021] Figure 2 It shows the variation of the contact angle of the loofah sponge-based cross-linked hydrophobic and lipophilic modified oil-absorbing material prepared in Example 1 of the present invention for water with the number of cycles. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be further described below in conjunction with embodiments, but it is not intended to limit the present invention.

[0023] Example 1

[0024] A preparation method of a loofah sponge-based cross-linked hydrophobic and lipophilic modified oil-absorbing material includes the following steps:

[0025] Peel and seed the mature loofah sponge fruit, and immerse it in distilled water, squeeze it several times until no more impurities fall off and the color changes. Then re-immerse the loofah sponge in fresh distilled water, change the water every 3 h, take it out after 12 h, air-dry it naturally, and cut the loofah sponge into 0.3 cm specimens. Immerse the specimens in 10% NaOH aqueous solution, stir and treat them at 80 °C for 3 h, take them out, wash them with distilled water until neutral, and dry them for standby.

[0026] Add 1 g of the loofah sponge pretreated with alkali solution to ethanol, then stir and add 0.1 g of bisphenol dicycloglycerol ether and 0.03 g of formic acid. After stirring and reacting the reaction solution at 40 °C for 10 h, add 0.4 g of epoxy octadecane to the reaction solution, and continue to stir and react at 40 °C for 10 h. After the reaction, filter by suction, wash repeatedly with ethanol, and dry to obtain the loofah sponge-based cross-linked hydrophobic and lipophilic modified oil-absorbing material.

[0027] The relevant performance experiments of the loofah sponge-based cross-linked hydrophobic and lipophilic modified oil-absorbing material of Example 1 are as follows:

[0028] Water contact angle test: A contact angle tester (model SDC-350H) was used to characterize the hydrophobicity of the materials. The sample was adhered to a glass slide, and 5 μl of water was dropped onto the surface of the sample using a syringe. Five different positions of each sample were measured, and the average value was taken. The results are listed in Table 1.

[0029] Oil absorption capacity test: First, the sample was dried in an oven at 60 °C for 2 h and then weighed. The initial weight was recorded as M 0 . Then the sample was placed in a mixed system of engine oil and water. After 15 min, the sample was taken out and placed on a metal filter. After standing and dripping for 3 min, the sample was placed in an oven at 60 °C again for drying treatment for 4 h and then weighed. The weight was recorded as M t . Each sample was measured three times, and the average value was taken. The oil absorption capacity (AR) of the sample was calculated according to the following formula, and the results are listed in Table 1.

[0030]

[0031] Reusability: The oil agent adsorbed by the impregnated sample was extruded by mechanical extrusion. Each oil-water separation and each extrusion were regarded as one cycle. The changes in the water contact angle and oil absorption capacity of the sample with the number of extrusion times were recorded to judge the reusability of the sample. The results of Example 1 are as Figure 1 and Figure 2 shown. It can be seen that with the increase in the number of recycling times, the prepared loofah-based crosslinked hydrophobic and oleophilic modified oil-absorbing material only showed a slight decrease in oil absorption and water contact angle, and still maintained excellent oil absorption ability and excellent hydrophobic characteristics. It shows that the loofah crosslinked hydrophobic and oleophilic modification technology adopted in the present invention effectively enhances the durability of the loofah. Specifically, the crosslinking modification endows the loofah with stronger compressive ability in practical applications, effectively preventing its structure from being squeezed and damaged when stressed; while the covalent hydrophobic and oleophilic modification ensures that the hydrophobic layer is not easily detached during repeated use, thus greatly improving the recycling rate of the loofah.

[0032] Example 2

[0033] The loofah was treated with an alkali solution in the same pretreatment method as in Example 1. 1 g of the loofah pretreated with the alkali solution was added to ethanol, and then 0.2 g of bisphenol dicycloglycerol ether and 0.05 g of acetic acid were added with stirring. After the reaction solution was stirred and reacted at 50 °C for 8 h, 0.6 g of epoxy octadecane was added to the reaction solution, and the reaction was continued to stir at 50 °C for 8 h. After the reaction, it was filtered, washed repeatedly with ethanol, and dried to obtain a loofah-based crosslinked hydrophobic and oleophilic modified oil-absorbing material. Its water contact angle and oil absorption capacity were measured according to the relevant performance experiments of the product in Example 1, and the results are listed in Table 1.

[0034] Example 3

[0035] The loofah sponge was treated with an alkali solution in the same pretreatment manner as in Example 1. 1 g of the alkali solution-pretreated loofah sponge was added to ethanol, and then 0.3 g of bisphenol dicycloglycerol ether and 0.07 g of formic acid were added with stirring. After the reaction solution was stirred at 60 °C for 6 h, 0.8 g of epoxy octadecane was added to the reaction solution, and the reaction was continued with stirring at 60 °C for 6 h. After the reaction, suction filtration was carried out, and the product was repeatedly washed with ethanol and dried to obtain a loofah sponge-based crosslinked hydrophobic and lipophilic modified oil-absorbing material. Its water contact angle and oil absorption capacity were measured according to the relevant performance experiments of the product in Example 1, and the results are listed in Table 1.

[0036] Comparative Example 1

[0037] A preparation method of a loofah sponge-based crosslinked modified oil-absorbing material: The loofah sponge was treated with an alkali solution in the same pretreatment manner as in Example 1. 1 g of the alkali solution-pretreated loofah sponge was added to ethanol, and then 0.1 g of bisphenol dicycloglycerol ether and 0.03 g of formic acid were added with stirring. The reaction solution was stirred at 40 °C for 10 h. After the reaction, suction filtration was carried out, and the product was repeatedly washed with ethanol and dried to obtain a loofah sponge-based crosslinked modified oil-absorbing material. Its water contact angle and oil absorption capacity were measured according to the relevant performance experiments of the product in Example 1, and the results are listed in Table 1.

[0038] Comparative Example 2

[0039] A preparation method of a loofah sponge-based hydrophobic and lipophilic modified oil-absorbing material: The loofah sponge was treated with an alkali solution in the same pretreatment manner as in Example 1. 1 g of the alkali solution-pretreated loofah sponge was added to ethanol, and then 0.4 g of epoxy octadecane and 0.03 g of formic acid were added with stirring. The reaction solution was stirred at 40 °C for 10 h. After the reaction, suction filtration was carried out, and the product was repeatedly washed with ethanol and dried to obtain a loofah sponge-based hydrophobic and lipophilic modified oil-absorbing material. Its water contact angle and oil absorption capacity were measured according to the relevant performance experiments of the product in Example 1, and the results are listed in Table 1.

[0040] Table 1 Water contact angle and adsorption amount of engine oil of the adsorption materials prepared in Examples 1-3 and Comparative Examples 1-2

[0041]

[0042] In the examples of the present invention, for the prepared loofah sponge-based crosslinked hydrophobic and lipophilic modified oil-absorbing material, the hydrophobic substance is tightly grafted into the loofah sponge through stable covalent bonds, significantly enhancing the hydrophobic property of the loofah sponge. Its surface water contact angle is as high as 149.7°, showing excellent hydrophobic performance. In addition, the adsorption material also has a rich pore structure and a large number of lipophilic groups, which enables it to show excellent ability in oil-water separation, and the adsorption amount of silicone oil can reach 18.9 g / g.

[0043] In contrast, the loofah sponge in Comparative Example 1 was only subjected to cross-linking modification and not further covalently hydrophobic modified; while Comparative Example 2 was only subjected to covalent hydrophobic and lipophilic modification. Therefore, the modified loofah sponges prepared in these two comparative examples could not match the modified loofah sponges in the examples in terms of the number of lipophilic groups and the richness of the pore structure, which also directly led to a significant decrease in their hydrophobicity and the silicone oil adsorption capacity.

Claims

1. A method for preparing a luffa-based cross-linked hydrophobic and lipophilic modified oil-absorbing material, characterized in that: The following steps are involved: (1) cross-linking and grafting bisphenol diglycerol between fibers in the loofah pretreated with alkali solution to obtain a cross-linked modified loofah, specifically, adding the loofah pretreated with alkali solution into ethanol, adding bisphenol diglycerol, and adding an organic acid as a catalyst to carry out a cross-linking and grafting reaction, wherein the mass ratio of the loofah pretreated with alkali solution, bisphenol diglycerol, and the organic acid is 1: (0.1-0.3): (0.03-0.07); (2) The cross-linked modified loofah is modified with a hydrophobic and lipophilic long-chain alkyl compound to obtain a loofah-based cross-linked hydrophobic and lipophilic modified oil-absorbing material, specifically, the hydrophobic and lipophilic long-chain alkyl compound is added to the reaction solution after the cross-linking and grafting reaction in step (1), and the reaction is continued by stirring, wherein the mass ratio of the loofah pretreated with alkali solution to the long-chain alkyl compound is 1: (0.4-0.8).

2. The preparation method of the luffa-based cross-linked hydrophobic and lipophilic modified oil-absorbing material according to claim 1, characterized in that: The organic acid is one of formic acid and acetic acid.

3. The preparation method of the luffa-based cross-linked hydrophobic and lipophilic modified oil-absorbing material according to claim 1, characterized in that, The cross-linking and grafting reaction in step (1) is carried out by stirring at 40-60° C. for 6-10 hours.

4. The preparation method of the luffa-based cross-linked hydrophobic and lipophilic modified oil-absorbing material according to claim 1, characterized in that: The hydrophobic and lipophilic long-chain alkyl compound is a hydrophobic and lipophilic alkylene oxide.

5. The method for preparing the luffa-based cross-linked hydrophobic and lipophilic modified oil-absorbing material according to claim 1, wherein: After adding the hydrophobic and lipophilic long-chain alkyl compound in step (2), stirring and reacting at 40-60° C. for 6-10 hours is continued. After the reaction, suction filtration, repeated washing with ethanol and drying are performed to obtain the luffa-based cross-linked hydrophobic and lipophilic modified material.

6. The method for preparing the luffa-based cross-linked hydrophobic and lipophilic modified oil-absorbing material according to claim 1, wherein: The alkaline solution pretreatment is to soak the loofah in a 2% to 15% NaOH aqueous solution, stir and treat it at 60 to 100° C. for 2 to 5 hours, and then wash it with deionized water until it is neutral.

7. A loofah-based cross-linked hydrophobic and lipophilic modified oil-absorbing material, characterized in that: The invention is prepared by the preparation method of the loofah-based cross-linked hydrophobic and lipophilic modified oil-absorbing material according to any one of claims 1 to 6.

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