Preparation method of super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation
By preparing a superhydrophobic microalgae-polyvinyl alcohol crosslinked network aerogel, combining the photothermal properties of microalgae with the crosslinked network of polyvinyl alcohol, the problems of low adsorption efficiency of high-viscosity crude oil and high cost of traditional materials were solved, achieving efficient and low-cost oil-water separation.
Patent Information
- Application Number
- CN202511096487.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-06
- Publication Date
- 2025-10-24
AI Technical Summary
Existing adsorbents are inefficient, costly, and difficult to recycle when treating high-viscosity crude oil. Traditional photothermal materials have complicated preparation processes and are difficult to apply on a large scale. Microalgae as adsorbents suffer from poor mechanical strength and low adsorption efficiency.
By combining microalgae with polyvinyl alcohol crosslinked network aerogel, the viscosity of crude oil is reduced through photothermal effect, and superhydrophobic microalgae-polyvinyl alcohol crosslinked network aerogel is prepared. The photothermal properties of microalgae and hydrogen bonding of polyvinyl alcohol are used to form a three-dimensional network, constructing a microporous structure and performing hydrophobic modification.
It achieves efficient and low-cost oil-water separation. The material has good mechanical strength and stability, and can quickly reduce the viscosity of crude oil under light irradiation, thereby improving adsorption efficiency. It is suitable for rapid separation at large-area crude oil spill sites.
Smart Images
Figure CN120829620A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of crude oil adsorption, and particularly relates to a preparation method of super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation. BACKGROUND
[0002] Crude oil is a mixture of various alkanes, cycloalkanes and aromatic hydrocarbons, and has a high viscosity and poor flowability. Crude oil plays an increasingly important role in daily life. However, the increasingly serious ecological environmental problems, such as offshore oil pipeline leakage, industrial oil-containing wastewater and organic pollutant discharge, have caused considerable damage and far-reaching influence on marine organisms, tourism and human health. Therefore, how to quickly clean the high-viscosity oil spill on the sea is a technical problem to be solved in the field, but it is still a great challenge.
[0003] Adsorbents with hydrophobicity and lipophilicity are considered to be ideal candidate materials for oil spill remediation. However, traditional adsorbents are not suitable for thick oil, which will block the pore structure and result in poor adsorption efficiency. In this case, researchers have paid extensive attention to new adsorbent materials based on photothermal conversion technology. By compounding porous matrices such as sponges, aerogels and diatomite with photosensitive materials, an intelligent adsorption system with super-hydrophobic and super-lipophilic properties is successfully constructed. The above-mentioned materials can quickly increase the surface temperature under light conditions through the photothermal effect, and significantly enhance the flowability of the surrounding high-viscosity crude oil, so as to realize effective adsorption of high-viscosity crude oil. However, there are still the following technical problems in the recycling process of the above-mentioned materials for adsorbing high-viscosity crude oil on the sea: complicated preparation process, high cost and difficult to be applied on a large scale.
[0004] Microalgae, as microorganisms widely existing in the natural environment, have been proved to be high-efficiency adsorbents for heavy metal ions and dyes and other pollutants, and have the advantages of green environmental protection, safety and biodegradability. The surface of microalgae has lipophilic properties, and some microalgae have the ability of photothermal conversion, which can increase the temperature and reduce the viscosity of crude oil under light, and improve the adsorption efficiency. Therefore, the adsorbent prepared from microalgae is a low-cost and environmentally friendly crude oil remover. However, the single microalgae as an adsorbent has the problems of low crude oil adsorption efficiency, poor mechanical strength and difficult recycling. Therefore, how to use microalgae to prepare an adsorbent with high crude oil adsorption efficiency, good mechanical strength and easy recycling has become a technical problem to be solved in the field. SUMMARY
[0005] To solve the above technical problems, the application provides a preparation method of super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation.
[0006] To achieve the above-mentioned purposes, the application provides the following technical solutions.
[0007] The application provides a preparation method of a super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation.
[0008] (1) adding a microalgae aqueous solution into a polyvinyl alcohol (PVA) aqueous solution to obtain a mixed solution;
[0009] (2) mixing the mixed solution, a foaming agent and a binder, stirring and foaming, freezing and drying to obtain a photo-thermal microalgae composite aerogel;
[0010] (3) performing surface hydrophobic treatment on the photo-thermal microalgae composite aerogel by using a polydimethylsiloxane (PDMS) solution to obtain the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation.
[0011] Technical principle: the application takes microalgae as a substrate, and the microalgae has good photo-thermal effect, generates heat energy through thermal radiation under light conditions, reduces the viscosity of crude oil, and thus improves the oil-water separation efficiency. Meanwhile, based on the rich functional groups such as hydroxyl and amino groups of the microalgae, the microalgae can be cross-linked with polyvinyl alcohol to form a three-dimensional network through hydrogen bonds, a large number of microporous structures are successfully constructed on the surface of the aerogel by combining a mechanical stirring and foaming method, and then the polydimethylsiloxane is grafted and modified, and finally the microalgae-polyvinyl alcohol cross-linked network aerogel with rich pore structure, super-hydrophobicity, high thermal conductivity and stable structure is obtained.
[0012] Further, in step (1), the microalgae in the microalgae aqueous solution are selected from one or more of diatom, chlorella pyrenoidosa, chlorella vulgaris, chlorella kessleri, spirulina, green algae, chlorella, oscillato and haematococcus pluvialis.
[0013] Further, in step (1), the concentration of the microalgae aqueous solution is 1-20wt%; the concentration of the polyvinyl alcohol aqueous solution is 1-10wt%; and the mass ratio of the microalgae in the microalgae aqueous solution to the polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 1:(0.1-1).
[0014] Further, in step (2), the mass ratio of the foaming agent, the binder to the microalgae in the microalgae aqueous solution in step (1) is (0.1-3):(0.1-2):1.
[0015] Further, in step (2), the binder is selected from one or more of polyvinyl acetate, polyurethane, urea-formaldehyde glue and phenol-formaldehyde glue; and / or,
[0016] The foaming agent is selected from one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and rosin soap foaming agent.
[0017] Further, in step (2), the stirring foaming rotation speed is 1000-3000 rad / min, and the volume expands to 4-8 times of the original volume after stirring foaming.
[0018] Further, in step (2), the freezing temperature is-20 DEG C, and the freezing time is 5-12 h; the drying is vacuum drying; the vacuum drying temperature is-40 DEG C, and the vacuum drying time is 12-24 h.
[0019] Further, in step (3), the surface hydrophobic treatment mode is soaking; and the soaking time is 5-10 min.
[0020] The application provides a super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared by the preparation method.
[0021] The application further provides application of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel in the field of crude oil adsorption.
[0022] Compared with the prior art, the application has the following advantages and technical effects:
[0023] (1) The microalgae has the advantages of low cost, biodegradability, hydrophilicity and lipophilicity, and rich source, and is an ideal green crude oil pollution treatment material; based on this, the microalgae is mixed with PVA to form a uniform solution, and then a kind of aerogel with a unique cross-linked network structure and pores is prepared through continuous mechanical foaming, freezing and drying. The introduction of the microalgae significantly improves the photo-thermal properties of the material. The physical mechanical foaming overcomes the problem that the photo-thermal materials in the photo-thermal super-hydrophobic materials prepared by traditional impregnation, spraying and in-situ growth are easy to fall off, causing the photo-thermal performance of the material to decrease. The aerogel material prepared by the application has good mechanical properties, porosity and cycle stability, and has good development prospects in the field of adsorption and recovery of high-viscosity petroleum.
[0024] (2) The super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared by the application has high adsorption capacity and high adsorption rate, and also has good stability in cyclic use, and does not cause secondary pollution.
[0025] (3) The super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared by the application has a hydrophobic contact angle of 125 DEG, has good hydrophobic and lipophilic properties and photo-thermal properties, the photo-thermal test temperature can be as high as 69.3 DEG C, has potential adsorption capacity for crude oil, and as the temperature increases, the viscosity of the crude oil decreases obviously, so that long-term adsorption of offshore crude oil can be realized.
[0026] (4) The preparation method of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel provided by the application has the advantages of low cost, simple operation and environmental friendliness, is suitable for efficient and rapid oil-water separation in a large-area oil leakage site, and realizes waste treatment with waste. BRIEF DESCRIPTION OF DRAWINGS
[0027] The drawings that form a part of this application provide further understanding of the application, and the illustrative embodiments of the application and their description serve to explain the application, and do not constitute improper limitations on the application. In the drawings:
[0028] Figure 1 Process flow chart for the preparation method of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation in Example 1;
[0029] Figure 2 Actual physical diagram of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1;
[0030] Figure 3 Scanning electron microscope diagram of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1;
[0031] Figure 4 Schematic diagram of the hydrophobic contact angle of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1;
[0032] Figure 5 Photothermal test result of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1;
[0033] Figure 6 Infrared camera diagram of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1;
[0034] Figure 7 Adsorption of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 on crude oil (a) and dichloromethane (b);
[0035] Figure 8 Adsorption of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 on crude oil under photothermal conditions. DETAILED DESCRIPTION
[0036] The technical solutions in the embodiments of the application will be described below in detail with reference to the drawings of the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.
[0037] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.
[0038] The present application provides a preparation method of a super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation, comprising the following steps:
[0039] (1) adding a microalgae aqueous solution into a polyvinyl alcohol aqueous solution to obtain a mixed solution;
[0040] (2) mixing the mixed solution, a foaming agent and a binder, and then stirring and foaming, and then freezing and drying to obtain a photo-thermal microalgae composite aerogel;
[0041] (3) performing a surface hydrophobic treatment on the photo-thermal microalgae composite aerogel with a polydimethylsiloxane solution to obtain the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation.
[0042] In a preferred embodiment, in step (1), the microalgae in the microalgae aqueous solution are selected from one or more of diatom, chlorella vulgaris, chlorella ellipsoidea, chlorella kessleri, spirulina, green algae, chlorella, oscillato and haematococcus pluvialis, and are further preferably selected from one or more of chlorella vulgaris, chlorella ellipsoidea, chlorella kessleri and spirulina. Microalgae have the advantages of low cost, biodegradability, hydrophilic and lipophilic, and abundant source, and are ideal green crude oil pollution treatment materials. The microalgae are used as a substrate to prepare the aerogel for efficient solar-driven oil-water separation, which can generate heat energy through thermal radiation under light conditions, reduce the viscosity of crude oil, and thus improve the oil-water separation efficiency.
[0043] In a preferred embodiment, in step (1), the concentration of the microalgae aqueous solution is 1-20 wt%, and is further preferably 5-15 wt%; the concentration of the polyvinyl alcohol aqueous solution is 1-10 wt%, and is further preferably 5-10 wt%; and the mass ratio of the microalgae in the microalgae aqueous solution to the polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 1:(0.1-1), and is further preferably 1:(0.3-0.6). The amount of the microalgae and the polyvinyl alcohol in the present application will affect the forming degree and mechanical properties of the aerogel.
[0044] In a preferred embodiment, in step (1), the preparation method of the polyvinyl alcohol aqueous solution is: dissolving polyvinyl alcohol in deionized water, and heating and stirring to obtain; the temperature of the heating and stirring is 80-110℃, and the time of the heating and stirring is 0.5-2h.
[0045] In the preferred embodiment, in step (2), the mass ratio of the foaming agent, the binder and the microalgae in the aqueous solution of the microalgae in step (1) is (0.1-3):(0.1-2):1, and further preferably (0.1-2):(0.1-1):1. The amount of the foaming agent and the binder in the present application will affect the pore structure and mechanical strength of the aerogel.
[0046] In the preferred embodiment, in step (2), the binder is selected from one or more of polyvinyl acetate, polyurethane, urea-formaldehyde glue and phenol-formaldehyde glue, and further preferably polyvinyl acetate and / or polyurethane.
[0047] In the preferred embodiment, in step (2), the foaming agent is selected from one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and rosin soap foaming agent, and further preferably sodium dodecyl benzene sulfonate and / or sodium dodecyl sulfate.
[0048] In the preferred embodiment, in step (2), the stirring foaming speed is 1000-3000 rad / min, and the volume expansion after stirring foaming is 4-8 times the original volume.
[0049] In the preferred embodiment, in step (2), the freezing temperature is-20℃, and the freezing time is 5-12 h.
[0050] In the preferred embodiment, in step (2), the drying is vacuum drying, the vacuum drying temperature is-40℃, and the vacuum drying time is 12-24 h.
[0051] In the preferred embodiment, in step (3), the concentration of the polydimethylsiloxane solution is 25 wt%, and the solvent of the polydimethylsiloxane solution is dichloromethane.
[0052] In the preferred embodiment, in step (3), the surface hydrophobic treatment is by immersion, and the immersion time is 5-10 min.
[0053] In the preferred embodiment, in step (3), the surface hydrophobic treatment further comprises a drying step, the drying temperature is 50-100℃, and the drying time is 2-12 h.
[0054] The present application provides a super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared by the preparation method described in the above technical solution.
[0055] The present application also provides a use of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel described in the above technical solution in the field of crude oil adsorption.
[0056] In the present application, room temperature refers to "25±2℃".
[0057] The raw materials in the embodiments of the present application are all purchased through the market route unless otherwise specified.
[0058] Example 1
[0059] A preparation method of a super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation, the process flow chart is shown in Figure 1 , and the steps are as follows:
[0060] (1) 5 g of Chlorella pyrenoidosa was added to 30 mL of deionized water to prepare a Chlorella pyrenoidosa aqueous solution with a concentration of about 14%; 10 g of PVA was added to 100 mL of deionized water and heated and stirred at 100℃ for 1 h to prepare a PVA aqueous solution with a concentration of 10 wt%; 15 mL of the PVA aqueous solution with a concentration of 10 wt% was added to the Chlorella pyrenoidosa aqueous solution (i.e., the mass ratio of Chlorella pyrenoidosa to PVA was 1:0.3), and stirred at a speed of 2000 rad / min for 5 min to obtain a mixed solution.
[0061] (2) 5 g of polyvinyl acetate and 5 g of sodium dodecyl benzene sulfonate were sequentially added to the mixed solution obtained in step (1) and stirred at 2000 rad / min to foam, and when the foaming ratio of the foam reached 8 times the original volume, the foam was slowly poured into a mold, and left to stand for 5 min, and then frozen at -20℃ for 10 h, and then vacuum dried at -40℃ for 24 h to obtain a light-heat microalgae composite aerogel.
[0062] (3) The light-heat microalgae composite aerogel obtained in step (2) was soaked in a PDMS solution with a concentration of 25 wt% for hydrophobic modification treatment for 7 min, and then dried at 90℃ for 3 h to obtain a super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel.
[0063] Figure 2 A physical diagram of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1.
[0064] Figure 3 A scanning electron microscope image of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1. It can be seen from Figure 3 that the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 has a porous structure.
[0065] Figure 4 A schematic diagram of the hydrophobic contact angle of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1. It can be seen from Figure 4 that the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 has good hydrophobicity, and the hydrophobic angle is 125.06°.
[0066] The super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 was placed under a light intensity of 1 kW m -2 Irradiate under xenon lamp for 15 minutes, and test the surface temperature at the same time. Figure 5 .
[0067] Figure 5 The photothermal test results of the super hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1. Figure 5 It can be seen that the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 has a light intensity of 1 kW m -2 After irradiation under a xenon lamp for 15 minutes, the surface temperature can reach up to 69.3℃.
[0068] Figure 6 This is an infrared image of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1. Figure 6 The super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 was shown to be -2 The surface temperature changes during irradiation under xenon lamp. Figure 5 , which confirmed that the superhydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel has good photothermal properties, which is conducive to the adsorption of high-viscosity crude oil.
[0069] The super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 was placed in a mixed solution of dichloromethane and water (the volume ratio of dichloromethane to water was 1:50) and a mixed solution of crude oil and water (the volume ratio of crude oil to water was 1:50) for 1 min, and the adsorption was observed. The results are shown in FIG. Figure 7 .
[0070] Figure 7 The adsorption of crude oil (a) and dichloromethane (b) by the super hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 is shown in FIG. Figure 7 As can be seen from part a of the figure, the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 is placed in a mixed solution of crude oil and water, and can completely absorb the crude oil (black) in the water, indicating that it has a high adsorption capacity for crude oil. Figure 7 As can be seen from part b, since the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 has good hydrophobicity, it can selectively adsorb dichloromethane (red) when placed in a mixed solution of dichloromethane and water.
[0071] The super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 was placed in a mixed solution of crude oil and water (the volume ratio of crude oil to water was 1:3) and a light intensity of 1 kWm was used. -2The xenon lamp is irradiated, and a peristaltic pump is connected, one end of the peristaltic pump is inserted into the aerogel surface, and the other end is placed in an empty beaker, and the adsorption result is shown in Figure 8 .
[0072] Figure 8 The adsorption of crude oil on the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in Example 1 under the light-thermal condition is shown in Figure 8 It can be seen that under the irradiation of the xenon lamp with an intensity of 1 kW m -2 With the assistance of the peristaltic pump, the crude oil is recovered into the right beaker after 6 minutes, because the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared in the application has excellent light-thermal conversion performance, the surface temperature of the aerogel is increased under irradiation, so that the temperature of the crude oil is increased, the viscosity is reduced, and the adsorption and recovery rate of the crude oil is improved.
[0073] Example 2
[0074] A preparation method of a super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation, the steps are as follows:
[0075] (1) 5g of spirulina is added to 30mL of deionized water to prepare a spirulina aqueous solution with a concentration of about 14%; 10g of PVA is added to 100mL of deionized water, heated and stirred at 100℃ for 1h to prepare a PVA aqueous solution with a concentration of 10wt%; 15mL of the PVA aqueous solution with a concentration of 10wt% is added to the spirulina aqueous solution (i.e. the mass ratio of spirulina to PVA is 1:0.3), stirred for 5min at a speed of 2000rad / min to obtain a mixed solution.
[0076] Step (2) is the same as Example 1.
[0077] Example 3
[0078] A preparation method of a super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation, the steps are as follows:
[0079] (1) 5g of spirulina is added to 30mL of deionized water to prepare a spirulina aqueous solution with a concentration of about 14%; 10g of PVA is added to 100mL of deionized water, heated and stirred at 100℃ for 1h to prepare a PVA aqueous solution with a concentration of 10wt%; 15mL of the PVA aqueous solution with a concentration of 10wt% is added to the spirulina aqueous solution (i.e. the mass ratio of spirulina to PVA is 1:0.3), stirred for 5min at a speed of 2000rad / min to obtain a mixed solution.
[0080] (2) To the mixed solution obtained in step (1), 3 g of polyvinyl acetate and 3 g of sodium dodecyl benzene sulfonate were added, and the foam was stirred at 2000 rad / min. When the foaming ratio of the foam reached 8 times the original volume, the foam was slowly poured into a mold, and was left to stand for 5 min. Then, the foam was frozen at -20°C for 10 h, and was vacuum dried at -40°C for 24 h to obtain the photo-thermal microalgae composite aerogel.
[0081] (3) The photo-thermal microalgae composite aerogel obtained in step (2) was soaked in a PDMS solution with a concentration of 25 wt% for 7 min for hydrophobic modification treatment, and was then dried at 90°C for 3 h to obtain the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel.
[0082] Comparative Example 1
[0083] A method for preparing a photo-thermal microalgae composite aerogel, comprising the following steps:
[0084] (1) 5 g of spirulina was added to 30 mL of deionized water to prepare a spirulina aqueous solution with a concentration of about 14%. 10 g of PVA was added to 100 mL of deionized water, and the mixture was heated and stirred at 100°C for 1 h to prepare a PVA aqueous solution with a concentration of 10 wt%. 15 mL of the PVA aqueous solution with a concentration of 10 wt% was added to the spirulina aqueous solution (i.e., the mass ratio of spirulina to PVA was 1:0.3), and the mixture was stirred at 2000 rad / min for 5 min to obtain a mixed solution.
[0085] (2) To the mixed solution obtained in step (1), 5 g of polyvinyl acetate and 5 g of sodium dodecyl benzene sulfonate were added, and the foam was stirred at 2000 rad / min. When the foaming ratio of the foam reached 8 times the original volume, the foam was slowly poured into a mold, and was left to stand for 5 min. Then, the foam was frozen at -20°C for 10 h, and was vacuum dried at -40°C for 24 h to obtain the photo-thermal microalgae composite aerogel.
[0086] Comparative Example 2
[0087] A method for preparing a photo-thermal microalgae composite aerogel, comprising the following steps:
[0088] (1) 5 g of spirulina was added to 30 mL of deionized water to prepare a spirulina aqueous solution with a concentration of about 14%. 10 g of PVA was added to 100 mL of deionized water, and the mixture was heated and stirred at 100°C for 1 h to prepare a PVA aqueous solution with a concentration of 10 wt%. 75 mL of the PVA aqueous solution with a concentration of 10 wt% was added to the spirulina aqueous solution (i.e., the mass ratio of spirulina to PVA was 1:1.5), and the mixture was stirred at 2000 rad / min for 5 min to obtain a mixed solution.
[0089] Step (2)-(3) are the same as in Example 2.
[0090] The aerogels prepared in Examples 1-3 and Comparative Examples 1-2 were tested for surface temperature after irradiation for 30 min under a xenon lamp with an illumination intensity of 1 kW m -2
[0091] The aerogels prepared in Examples 1-3 and Comparative Examples 1-2 were placed in a mixed solution of crude oil and water (volume ratio of crude oil to water 1:3), and irradiated using a xenon lamp with an illumination intensity of 1 kW m -2
[0092] Table 1
[0093] Water contact angle / ° Surface temperature / °C Oil absorption capacity / (g / g) Example 1 125.06 69.3 43.0 Example 2 113.56 62.9 37.4 Example 3 122.78 61.0 39.1 Comparative Example 1 0 53.8 25.8 Comparative Example 2 107.03 30.1 8.2
[0094] As can be seen from Table 1, after hydrophobic treatment, the water contact angle of the aerogel is significantly improved, the material is more hydrophobic, which is conducive to floating on the water surface to absorb oil, and the oil absorption capacity is significantly improved; the addition of different algal materials has a certain influence on the surface temperature, and the increase of different contents of the same algal material also has an influence on the surface temperature, because the chlorophyll content in different algal materials is different, thereby affecting the conversion efficiency of photo-thermal.
[0095] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.
Claims
1. A method for the preparation of superhydrophobic microalgae-polyvinyl alcohol cross-linked network aerogels for efficient solar-driven oil-water separation, characterized in that, The method comprises the following steps: (1) adding a microalgae aqueous solution into a polyvinyl alcohol aqueous solution to obtain a mixed solution; (2) mixing the mixed solution, a foaming agent and a binder, and then stirring and foaming, and then freezing and drying to obtain a photothermal microalgae composite aerogel; (3) performing surface hydrophobic treatment on the photothermal microalgae composite aerogel by using a polydimethylsiloxane solution to obtain the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel for efficient solar-driven oil-water separation.
2. The production method according to claim 1, characterized by, In step (1), the microalgae in the microalgae aqueous solution are selected from one or more of diatom, chlorella pyrenoidosa, chlorella vulgaris, chlorella kessleri, spirulina, green algae, chlorella, oscillato and haematococcus pluvialis.
3. The production method according to claim 1, characterized by, In step (1), the concentration of the microalgae aqueous solution is 1-20 wt%, the concentration of the polyvinyl alcohol aqueous solution is 1-10 wt%, and the mass ratio of the microalgae in the microalgae aqueous solution to the polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 1:(0.1-1).
4. The method of claim 1, wherein, In step (2), the mass ratio of the foaming agent, the binder to the microalgae in the microalgae aqueous solution in step (1) is (0.1-3):(0.1-2):
1.
5. The preparation method according to claim 1, characterized in that In step (2), the binder is selected from one or more of polyvinyl acetate, polyurethane, urea-formaldehyde glue and phenol-formaldehyde glue; and / or, The foaming agent is selected from one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and rosin soap foaming agent.
6. The method of claim 1, wherein, In step (2), the stirring and foaming speed is 1000-3000 rad / min, and the volume expansion after stirring and foaming is 4-8 times of the original volume.
7. The preparation method according to claim 1, characterized in that In step (2), the freezing temperature is-20℃, and the freezing time is 5-12 h; The drying is vacuum drying, the vacuum drying temperature is-40℃, and the vacuum drying time is 12-24 h.
8. The method of claim 1, wherein, In step (3), the surface hydrophobic treatment is performed by immersion, and the immersion time is 5-10 min.
9. A super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel prepared by the preparation method according to any one of claims 1-8.
10. Application of the super-hydrophobic microalgae-polyvinyl alcohol cross-linked network aerogel according to claim 9 in the field of crude oil adsorption.