CN111569839A - A kind of preparation method of hydrophobic and lipophilic adsorbent using loofah cotton as raw material - Google Patents

Abstract

The invention relates to a preparation method of a hydrophobic and lipophilic adsorbent using loofah cotton as a raw material, specifically: using loofah cotton as a raw material, firstly, soaking, washing and drying the material; secondly, immersing the material in an alkaline solution to carry out Pretreatment, then adjusted to neutrality with acid, washed and dried; thirdly, the alkali-treated material was immersed in a mixed solution of tetraethyl silicate, anhydrous ethanol and pure water, and then an appropriate amount of ammonia was added, and then washed with ethanol The fourth is to immerse the material in a mixed solution of cetyltrimethoxysilane and pure water, then add an appropriate amount of acetic acid, and then wash and dry with ethanol to obtain a modified adsorption material. Compared with the prior art, the invention can be widely used in oil leakage treatment and oily wastewater treatment, and the modified oil absorbing material has fast adsorption rate, low cost, and can be biodegraded without causing secondary environmental pollution.

Description

A kind of preparation method of hydrophobic and lipophilic adsorbent using loofah cotton as raw material

technical field

The invention belongs to the technical field of material surface modification and new adsorption materials, and relates to a preparation method of a hydrophobic and lipophilic adsorbent using loofah cotton as a raw material.

Background technique

Oil spills are an inevitable consequence of continued exploitation of fossil fuel resources. Surfactants, while capable of dissolving oil, can pose serious hazards to aquatic life and can lead to long-term contamination of the seabed. Large oil skimming equipment can remove oil, but the equipment is expensive, and the usefulness of these equipment is largely dependent on weather conditions. Therefore, in the existing main oil removal technologies, the use of oil adsorbents becomes more meaningful. The oil adsorbent has lipophilicity and hydrophobicity, and has a good oil-water separation function. And if the adsorbent has the ability to absorb oil into the material matrix, the adsorption capacity of the adsorbent will be further improved, so it is expected that the oil-absorbing material should have a porous structure. At the same time, the ideal oil-absorbing material should also have the characteristics of being reusable, non-toxic and harmless to the environment, and preferably biodegradable. Organic synthetic materials, including polymeric materials, such as polypropylene (PP) and polyurethane foam, are often used as commercial adsorption materials for water plants and marine oil spill treatment projects due to their lipophilic, hydrophobic, chemically stable, and high buoyancy properties. . The main disadvantage of these materials compared to mineral materials and natural fiber materials is that the rate of natural degradation is extremely slow or not at all, and at the same time, they cannot be naturally generated. It brings a lot of trouble to the adsorption recovery work and subsequent waste disposal work. Therefore, many domestic scholars focus their research on the search for biodegradable natural adsorption materials to solve the problem of polymeric materials. The present invention is proposed to solve the above-mentioned problems.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of a hydrophobic and lipophilic adsorbent using loofah cotton as a raw material in order to overcome the defects of the above-mentioned prior art. The prepared hydrophobic and lipophilic adsorbent can efficiently and rapidly adsorb oil pollutants in large quantities, and can be used for the adsorption of sudden oil pollution and the treatment of oily wastewater.

The object of the present invention can be realized through the following technical solutions:

A preparation method of a hydrophobic and lipophilic adsorbent using loofah cotton as a raw material, is characterized in that, comprises the following steps:

(1) Pretreatment: after cleaning and drying the raw material of loofah cotton, it is immersed in an alkaline solution, stirred for treatment, and then washed and dried to constant weight;

(2) Silicon loading treatment: Weigh pure water and add it to absolute ethanol, then add tetraethyl silicate under stirring conditions to obtain mixed solution 1, and then immerse the loofah cotton obtained after the treatment in step (1) into the mixed solution In solution one, stir, then add ammonia water, continue stirring, then wash and dry to constant weight;

(3) Hydrophobic and lipophilic treatment: weigh cetyltrimethoxysilane and add it to absolute ethanol, add acetic acid after stirring to obtain mixed solution II, and then immerse the loofah cotton obtained after the treatment in step (2) into mixed solution II stirring, and finally, washing and drying to constant weight to obtain the target product, the hydrophobic and lipophilic loofah cotton adsorbent.

Further, in step (1), the described luffa cotton raw material is a square with a side length of 2cm or a circle with a diameter of 2cm;

The specific cleaning and drying process is as follows: soak the raw loofah cotton in ultrapure water for 24-48h at room temperature, then wash it with pure water for several times, and finally, dry it in a vacuum oven at 50℃-70℃ until the quality is constant.

Further, in step (1), the alkaline solution is a NaOH solution with a concentration of 1wt%-5wt%;

The stirring treatment is specifically as follows: stirring for 5.0-10.0 h at a rotating speed of <500 r/min.

Further, in step (1), after stirring, the pH is adjusted to 6-8 with hydrochloric acid, and then washed with pure water for several times.

Further, in step (2), the ratio of the additions of the loofah cotton, tetraethyl silicate and ammonia water obtained after the treatment in step (1) is 2g: (1-5) mL: (1-5) mL, Wherein, the concentration of ammonia water is an aqueous solution containing 25wt%-28wt% of ammonia.

Further, in step (2), in the mixed solution one, the volume ratio of pure water, absolute ethanol and tetraethyl silicate is 20:(100-200):(1-5).

Further, in step (2), the loofah cotton obtained after the treatment in step (1) is immersed in the mixed solution, first stirred at room temperature for 10 minutes, then added with ammonia water, and then stirred at room temperature for 4-10 hours.

Further, in step (3), the ratio of the addition of loofah cotton, cetyltrimethoxysilane and acetic acid obtained after the treatment in step (2) is 2g: (1-5) mL: (0.5-3) mL.

Further, in the mixed solution 2 of step (3), the volume ratio of hexadecyltrimethoxysilane, absolute ethanol and acetic acid is (1-5):100:(0.5-3).

Further, in the step (3), the stirring process after the loofah cotton obtained after the treatment in the step (2) is immersed in the mixed solution 2 is specifically: stirring at a speed of not less than 500r/min at room temperature for 5-10h.

The present invention finds that, as a pure natural fiber material, loofah cotton contains about 60% of cellulose, about 30% of hemicellulose, 9.1% of lignin and 0.9% of pectin. When cellulose undergoes oxidative and grafting reactions, the active site is located on the hydroxyl groups of the 2nd, 4th, and 6th carbons of β-D-glucose. These active hydroxyl groups are surrounded by lignin, hemicellulose and pectin on the surface, so in order to achieve a better modification effect, the original material is usually pretreated before modification. The present invention adopts a chemical treatment method, which can It penetrates into the material and exposes a large number of hydroxyl groups inside the material, and the cellulose participates in the chemical modification reaction at a higher rate and the modification effect is better.

The hydrophilicity and hydrophobicity of a material is determined by how difficult it is for the liquid to spread over the surface of a solid substrate and displace the gas on the surface of the substrate. In the present invention, the material is modified from the surface microstructure of the material and the free energy of the surface of the material, wherein the micro-nanostructure obtained by modifying the surface of the material can make a large amount of air trapped in the grooves of the rough surface, thereby greatly reducing the amount of liquid The contact area between the droplet and the surface of the material makes the material hydrophobic; and since the surface free energy of the material is an important factor affecting the hydrophobicity of the solid surface, the present invention reduces the free energy of the surface of the material through modification, and increases the material accordingly. Hydrophobicity of the surface.

Luffa cotton is a biomass material, mainly composed of cellulose, lignin and hemicellulose, with a large content of active hydroxyl groups, which is easy to be functionalized and modified. Due to the physical and chemical properties of the loofah cotton material, it is selected as the raw material for the modification of the hydrophobic and lipophilic material in the present invention. In addition, the present invention also specifically limits the process conditions in the reaction process. First, the mechanical strength of the treated luffa cotton is greatly different with different treatment methods and different alkali solution concentrations, which will affect the application of the modified material in engineering practice; secondly, the stirring speed will affect the pretreatment effect and hydrophobic affinity. Oil modification effect. In the pretreatment process, the stirring speed is too low, so that the active hydroxyl groups in the material cannot be well exposed, which is not conducive to the subsequent hydrophobic and lipophilic functional modification, and the stirring speed is too high, which will damage the mechanical properties of the material. . Then, the dosage ratio of different materials during the hydrophobic and oleophilic modification will affect the effect of the hydrophobic modification of the material. Therefore, the present invention specifically limits these process conditions.

Compared with the prior art, the present invention has the following advantages:

1) The present invention utilizes loofah cotton as the raw material of the adsorbent, which is a natural biomass material, biodegradable, and will not cause secondary pollution, thereby solving the problem of secondary environmental pollution caused by the non-degradability of chemical oil-absorbing cotton;

2) This material is a common crop, with a large amount of domestic planting and a wide distribution range, and it is convenient and quick to obtain;

3) The adsorption material prepared by the present invention has a water contact angle of up to 151°, good hydrophobicity, a contact angle with oil of less than 10°, good oil adsorption, and can realize the separation of oil-containing wastewater without sudden change. It is used for adsorption when it is polluted by petroleum;

4) The preparation method of the adsorbent material of the present invention is simple, does not require heating at high temperature, does not require large-scale precision operating instruments, has low operating process difficulty, requires small capital investment, and has a wide range of raw material sources, can realize large-scale industrial production, and has good application prospects.

Description of drawings

Fig. 1 is the contact angle of the loofah cotton obtained with NaOH pretreatment method and water;

Fig. 2 is the contact angle of the loofah cotton that NaClO obtains with pretreatment method and water;

Fig. 3 is the contact angle of loofah cotton and water obtained by H ₂ O ₂ +NaOH pretreatment method;

Figure 4 is an optical picture of dirty scarlet dyed water droplets on loofah cotton;

Fig. 5 is the Fourier transform infrared spectrum of the loofah cotton obtained by different pretreatment methods;

Figure 6 is the SEM images of the material before and after modification (Figures a, b are Mag=100× and 1.0k×SEM images before modification, Figures e, c, d, and f are Mag=100×, 1.0k×, 5.0k×, 50.0k×SEM image);

Figure 7 shows the maximum adsorption capacity of the materials before and after modification for different organic substances.

8 is the water contact angle of the modified material obtained under the conditions of Comparative Example 1;

9 is the water contact angle of the modified material obtained under the conditions of Comparative Example 2;

Figure 10 is the water contact angle of the modified material obtained under the conditions of Comparative Example 3.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

In the following embodiments, the source of the loofah cotton used is obtained by removing the epidermis and the loofah seeds after planting the loofah in the farmland after the natural aging. The ammonia water used is an aqueous solution with a concentration of 25wt%-28wt% of ammonia.

If there is no special description of the raw materials or processing techniques, the rest are all conventional commercially available products or conventional processing techniques in the field.

Example 1:

The first step: pretreatment: use ultrapure water to soak the raw luffa cotton at room temperature (20-25°C) for 24.0 hours, wash three times with pure water, and dry it in a vacuum oven at 70°C until the quality is constant;

Step 2: Alkaline treatment: Immerse the loofah cotton pretreated in the first step in an alkaline solution, stir at room temperature (20-25°C) with a magnetic stirrer for 8.0 hours, and the alkaline solution is 5% wt NaOH solution, then adjusted pH to 7.0 with hydrochloric acid, washed several times with pure water, and dried in a vacuum oven at 70 °C until the quality was constant;

The third step: surface silicon loading treatment: add 20.0 mL of pure water to 100.0 mL of absolute ethanol, then add 2.0 mL of tetraethyl silicate under stirring conditions, and stir for 10 minutes to obtain mixed solution one. 2.0g was immersed in mixed solution 1, stirred at room temperature for 10min, then added with 1.0mL ammonia water, stirred at room temperature for 5.0h, then washed with absolute ethanol and pure water, and dried in a vacuum oven at 70°C until the quality was constant;

The fourth step: super-hydrophobicity and super-lipophilic treatment: immerse 2.0 g of the loofah cotton obtained in step 3 into mixed solution 2, and stir at room temperature for 5.0 h. The above mixed solution 2 is to add 1.0 mL of hexadecyltrimethoxysilane to 100 mL of In anhydrous ethanol solution, stir at room temperature for 10 min, and then add 1.0 mL of acetic acid to obtain; then wash with absolute ethanol and pure water, and dry in a vacuum oven at 70 °C until the quality is constant; obtain a hydrophobic and lipophilic loofah cotton adsorbent.

The contact angle between the adsorbent and water is shown in Figure 1, the Fourier transform infrared spectrum is shown in the spectral line in Figure 5, and the microstructure of the material surface is shown in Figure 6.

It can be seen from FIG. 1 that the contact angle between the adsorbent modified by the method of this embodiment and water can reach 150.6°, which fully achieves the effect of a superhydrophobic interface. It can be seen from Figure 4 that the dyed water droplets can roll on the surface of the material and completely "stand" on the surface of the material, and the material is not hydrophilic at all. As can be seen from Fig. 5, compared with the original unmodified material, the modified material has _SiO2 and -Si-O-Si- bond formation, while the infrared absorption of _-CH2 , _-CH3 organic groups The peaks are greatly enhanced, indicating that the material not only forms a SiO ₂ micro-nano rough surface, but also successfully grafts -CH ₂ , -CH ₃ organic groups, making the material achieve a hydrophobic effect. In Figure 6, the surface of the raw material before modification can be seen to be smooth and flat in Figures a and b, and the surface of the modified material is relatively rough in Figures c and d; it can be seen in Figure e that after modification The surface of the material is covered with a layer of nano-scale SiO ₂ raspberry-like particles, and the SiO ₂ particles have good dispersibility and cover the surface of the material more uniformly. It can be seen from the figure f that the SiO ₂ particles are more densely and uniformly dispersed on the surface of the material. . It can be seen from Figure 7 that the maximum adsorption capacity of the modified adsorbent for lubricating oil can reach about 14.0g/g, which is higher than the adsorption capacity before modification of about 12.0g/g, and the maximum adsorption capacity for diesel It is about 10.0g/g before modification and about 12.0g/g after modification. The maximum adsorption capacity for soybean oil is about 14.0g/g after modification and about 10.0g/g before modification.

Comparative Example 1:

Compared with Example 1, most of them are the same, except that the second step of alkali treatment is omitted. The experimental results are shown in Figure 8. It can be seen from the figure that the water contact angle of the modified material without alkali treatment is about 105°. Although it is a hydrophobic material, it cannot achieve the super-hydrophobic effect.

Comparative Example 2:

Compared with Example 1, most of the materials are the same, except that the third step of surface silicon loading treatment is omitted. Water-based materials, with a water contact angle of about 85°, cannot be used as oil-absorbing materials.

Comparative Example 3:

Compared with Example 1, most of them are the same, except that the fourth step of super-hydrophobic and super-oleophilic treatment is omitted. It is still a hydrophilic material after denaturation, with a water contact angle of about 65°, which is more hydrophilic than Comparative Example 2 and cannot be used for oil absorption treatment.

Example 2

The first step: pretreatment: use ultrapure water to soak the raw luffa cotton at room temperature (20-25°C) for 24.0 hours, wash three times with pure water, and dry it in a vacuum oven at 70°C until the quality is constant;

Step 2: Pretreatment: Immerse 2.0g of pretreated loofah cotton into the mixed solution, stir with a magnetic stirrer for 5.0h at 70°C, and the above alkaline solution is 1%wt NaOH+1%wt H ₂ O ₂ solution, then adjust the pH to 7.0 with hydrochloric acid, wash several times with pure water, and dry in a vacuum oven at 70°C to constant quality;

The third step: surface silicon loading treatment: add 20 mL of pure water to 100 mL of ethanol solution, then add 2 mL of tetraethyl silicate under stirring conditions, stir for 10 minutes to obtain a mixed solution, and immerse 2.0 g of alkali-treated loofah cotton into the mixed solution , stirred at room temperature for 10 min, then added 1.0 mL of ammonia water, stirred at room temperature for 5.0 h, then washed with absolute ethanol and pure water, and dried in a vacuum oven at 70 °C until the quality was constant;

The fourth step: super-hydrophobic and super-lipophilic treatment: 2.0 g of the loofah cotton obtained in step 3 was immersed in the mixed solution, and stirred for 5.0 h at room temperature. In the aqueous ethanol solution, stir at room temperature for 10 min, and then add 1.0 mL of acetic acid to obtain it; then wash it with absolute ethanol and pure water, and dry it in a vacuum oven at 70 °C until the quality is constant; obtain the hydrophobic and lipophilic loofah cotton adsorbent.

The contact angle between the hydrophobic and lipophilic loofah cotton adsorbent obtained in this example and water is shown in Figure 3, which can reach 149.6°. In addition, its Fourier infrared spectrum is shown in Figure 5. It can be seen from the figure that the modified The absorption peaks at 850, 2850, 2920 and 3000-3300 cm ^-1 wavenumbers of the material after characterization are enhanced, which proves that the modification of this method is relatively successful. Compared with Example 1, the same modification effect can be achieved.

Example 3

The first step: pretreatment: use ultrapure water to soak the raw luffa cotton at room temperature (20-25°C) for 24.0 hours, wash three times with pure water, and dry it in a vacuum oven at 70°C until the quality is constant;

Step 2: Pretreatment: Immerse 2.0g of pretreated loofah cotton in 100mg/L NaClO solution, stir with a magnetic stirrer for 24.0h at room temperature (20-25°C), and then adjust the pH to 7.0 with hydrochloric acid. Wash several times with pure water and dry in a vacuum oven at 70°C until the quality is constant;

The third step: surface silicon loading treatment: add 20.0 mL of pure water to 100.0 mL of ethanol solution, then add 2.0 mL of tetraethyl silicate under stirring conditions, and stir for 10 minutes to obtain a mixed solution. Add 2.0 g of alkali-treated loofah cotton Immerse in the mixed solution, stir at room temperature for 10 min, then add 1.0 mL of ammonia water, stir at room temperature for 5.0 h, then wash with absolute ethanol and pure water, and dry in a vacuum oven at 70 °C until the quality is constant;

The fourth step: super-hydrophobic and super-lipophilic treatment: 2.0 g of the loofah cotton obtained in step 3 was immersed in the mixed solution, and stirred for 5.0 h at room temperature. In the aqueous ethanol solution, stir at room temperature for 10 min, and then add 1.0 mL of acetic acid to obtain it; then wash it with absolute ethanol and pure water, and dry it in a vacuum oven at 70 °C until the quality is constant; obtain the hydrophobic and lipophilic loofah cotton adsorbent.

The contact angle between the hydrophobic and lipophilic loofah cotton adsorbent obtained in this example and water is shown in Figure 2, which can reach 149.3°. In addition, its Fourier infrared spectrum is shown in Figure 5. It can be seen from the figure that the modified The absorption peaks at 850, 2850, 2920 and 3000-3300 cm ^-1 wavenumbers of the material after characterization are enhanced, which proves that the modification of this method is relatively successful. Compared with Example 1, the same modification effect can be achieved.

Example 4:

Compared with Example 1, most of them are the same, except that in the surface-loaded silicon treatment process of the present example, the added amount of the loofah cotton, tetraethyl silicate, ammonia water, pure water, and anhydrous ethanol obtained after the treatment The ratio is 2g:1mL:1mL:20mL:150mL.

Example 5:

Compared with Example 1, most of them are the same, except that in the surface-loaded silicon treatment process of the present example, the added amount of the loofah cotton, tetraethyl silicate, ammonia water, pure water, and anhydrous ethanol obtained after the treatment The ratio is 2g:5mL:3mL:20mL:200mL.

Example 6:

Compared with Example 1, most of the results are the same, except that in the process of superhydrophobicity and superoleophilic treatment in this example, the addition of silicon-loaded loofah cotton, cetyltrimethoxysilane, acetic acid and absolute ethanol. The ratio of the amount is 2g:2mL:0.5mL:100mL.

Example 7:

Compared with Example 1, most of the results are the same, except that in the process of superhydrophobicity and superoleophilic treatment in this example, the addition of silicon-loaded loofah cotton, cetyltrimethoxysilane, acetic acid and absolute ethanol. The ratio of the amount is 2g:5mL:3mL:100mL.

In the above embodiments, the loofah cotton raw material used can be designed as a square with a side length of 2cm or a circle with a diameter of 2cm; in the alkali treatment process of the second step, the stirring speed needs to be <500r/min, preferably 300r/min Equal rotation speed; the stirring rotation speed of the fourth step is 500r/min, which can also be replaced by a rotation speed greater than 500r/min such as 600r/min.

The foregoing description of the embodiments is provided to facilitate understanding and use of the invention by those of ordinary skill in the art. It will be apparent to those skilled in the art that various modifications to these embodiments can be readily made, and the generic principles described herein can be applied to other embodiments without inventive step. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should all fall within the protection scope of the present invention.

Claims (10)

1. A preparation method of a hydrophobic oleophilic adsorbent taking silk melon cotton as a raw material is characterized by comprising the following steps:

(1) cleaning and drying the silk melon cotton raw material, then immersing the silk melon cotton raw material into an alkaline solution, stirring, washing and drying the silk melon cotton raw material to constant weight;

(2) weighing pure water, adding the pure water into absolute ethyl alcohol, adding tetraethyl silicate under the stirring condition to obtain a first mixed solution, then soaking the loofah cotton processed in the step (1) into the first mixed solution, stirring, adding ammonia water, continuously stirring, washing again, and drying to constant weight;

(3) and (3) weighing hexadecyl trimethoxysilane, adding the hexadecyl trimethoxysilane into absolute ethyl alcohol, stirring, adding acetic acid to obtain a mixed solution II, soaking the loofah cotton processed in the step (2) into the mixed solution II, stirring, washing, and drying to constant weight to obtain the target product, namely the hydrophobic oleophylic loofah cotton adsorbent.

2. The method for preparing the hydrophobic and lipophilic adsorbent from the silk melon cotton as the raw material according to claim 1, wherein in the step (1), the raw material of the silk melon cotton is square with the side length of 2cm or round with the diameter of 2 cm;

the cleaning and drying process specifically comprises the following steps: soaking a towel gourd cotton raw material in ultrapure water for 24-48h at room temperature, washing with pure water for multiple times, and finally drying in a vacuum oven at 50-70 ℃ until the quality is constant.

3. The method of claim 1The preparation method of the hydrophobic oleophilic adsorbent taking the silk melon cotton as the raw material is characterized in that in the step (1), the alkaline solution is NaOH solution with the concentration of 1 wt% -5 wt%, or 1 wt% NaOH +1 wt% WtH₂O₂Or 100mg/L NaClO solution;

the stirring treatment specifically comprises the following steps: stirring for 5.0-10.0h at the rotating speed of less than 500 r/min.

4. The method for preparing hydrophobic and lipophilic adsorbent from silk melon cotton as claimed in claim 1, wherein in step (1), after stirring, hydrochloric acid is used to adjust pH to 6-8, and then washing with pure water is performed several times.

5. The method for preparing the hydrophobic and lipophilic adsorbent from the towel gourd cotton as the raw material according to claim 1, wherein in the step (2), the addition ratio of the towel gourd cotton, the tetraethyl silicate and the ammonia water obtained after the treatment in the step (1) is 2 g: (1-5) mL: (1-5) mL, wherein the concentration of the ammonia water is 25 wt% -28 wt% of ammonia-containing aqueous solution.

6. The method as claimed in claim 1, wherein in the step (2), the volume ratio of pure water, absolute ethanol and tetraethyl silicate in the first mixed solution is 20 (100) to 200 (1-5).

7. The method for preparing the hydrophobic and lipophilic adsorbent from the loofah cotton as the raw material according to claim 1, wherein in the step (2), the loofah cotton treated in the step (1) is immersed in the mixed solution, stirred at room temperature for 10min, added with ammonia water, and then stirred at room temperature for 4-10 h.

8. The method for preparing the hydrophobic and lipophilic adsorbent by using the loofah cotton as the raw material according to claim 1, wherein in the step (3), the addition amount ratio of the loofah cotton obtained after the treatment in the step (2), the hexadecyl trimethoxysilane and the acetic acid is 2 g: (1-5) mL: (0.5-3) mL.

9. The method for preparing the hydrophobic and lipophilic adsorbent by using the silk melon cotton as the raw material according to claim 1, wherein in the mixed solution II in the step (3), the volume ratio of the hexadecyl trimethoxysilane to the absolute ethyl alcohol to the acetic acid is (1-5): 100: (0.5-3).

10. The method for preparing the hydrophobic and lipophilic adsorbent by using the loofah cotton as the raw material according to claim 1, wherein in the step (3), the stirring process after the loofah cotton treated in the step (2) is immersed in the mixed solution II is specifically as follows: stirring at room temperature at a rotation speed of not less than 500r/min for 5-10 h.

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