A photothermal superhydrophobic porous material based on ultra-light clay, its preparation method and application

Abstract

The present invention provides a photothermal superhydrophobic porous material based on ultra-light clay, its preparation method and application, belonging to the technical field of oil-water separation, and is used to solve the technical problem of poor adsorption of superhydrophobic adsorption materials to high-viscosity crude oil. The photothermal superhydrophobic porous material comprises the following steps: dispersing a carbon material and ultra-light clay in distilled water in sequence to obtain a mixed solution; adding a foaming agent to the mixed solution and continuously stirring until uniform foam appears in the mixed solution; freeze-drying the mixed solution to obtain a sponge based on ultra-light clay. Configuring a superhydrophobic modification solution, impregnating the sponge based on ultra-light clay in the superhydrophobic modification solution for hydrophobic modification to obtain the photothermal superhydrophobic porous material. The present invention has good photothermal performance, and the highest temperature in the photothermal test can reach 82.9 °C. It has potential adsorption capacity for crude oil, and with the increase of temperature, the viscosity of crude oil decreases significantly.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil-water separation, and particularly relates to a photothermal superhydrophobic porous material based on ultra-light clay, a preparation method thereof, and an application thereof. Background Art

[0002] With the continuous development of the industrial and transportation industries, the huge demand for crude oil by humans has intensified the exploitation of crude oil. Subsequently, the occurrence of oil spills during the exploitation and transportation processes has become more and more frequent, which has caused serious damage to the ecological environment, aquaculture, and human health. Traditional methods for treating oil spills mainly include controlled combustion, skimming, etc., which have the disadvantages of low efficiency and may cause secondary pollution. In recent years, photothermal superhydrophobic adsorption materials prepared by combining photothermal conversion materials with substrates such as sponges, aerogels, and diatomaceous earth have attracted extensive attention from researchers due to their advantages of superhydrophobicity and superoleophilicity. At the same time, due to the presence of the photothermal conversion material, the surface temperature of the superhydrophobic adsorption material rises rapidly under sunlight irradiation, resulting in a decrease in the viscosity of the surrounding crude oil, thereby realizing the effective adsorption of high-viscosity crude oil.

[0003] Patent Publication No. CN111229168A discloses a method for recovering highly viscous leaked crude oil using a graphene-based material. Graphene oxide is loaded onto the framework of a melamine sponge material through an impregnation method, and then the graphene oxide is reduced to graphene to obtain the graphene-based material. The temperature of the crude oil leaked on the sea surface is increased by light irradiation, and the graphene material is added to adsorb the crude oil. Patent Publication No. CN114452960A discloses a light-driven oil-absorbing MXene-modified melamine sponge and its preparation method. The melamine sponge is impregnated in a mixed solution composed of MXene, polydimethylsiloxane, and an organic solvent, and then the sponge modification liquid mixture is transferred to a hydrothermal reaction kettle for hydrothermal reaction, and finally taken out and dried. Patent Publication No. CN115491020A discloses a Janus-type composite foam photothermal functional material, its preparation method and application, that is, one side is superhydrophilic / underwater superoleophobic, and the other side is hydrophobic / superoleophilic. Preparation of the photothermal functional layer: First, MXene nanosheets are impregnated on one side of the porous foam through a coating method, and then a hydrophobic composite shielding layer is impregnated to endow the MXene-modified side with excellent hydrophobic properties and antioxidant shielding effects; Construction of Janus wettability: Using the impregnation method, hydrophilic functional components are loaded on the opposite side of the MXene modification of the porous foam to prepare a Janus-type MXene-based composite foam photothermal functional material with asymmetric wetting properties. In the above patents, functional materials with photothermal conversion are all loaded on porous foams / sponges by impregnation / coating methods, and the surface temperature of the superhydrophobic adsorption material is increased by sunlight irradiation to reduce the viscosity of the crude oil, thereby realizing the effective adsorption of highly viscous crude oil. However, due to the poor binding force between the photothermal conversion material and the matrix, it is difficult to increase the loading amount, and it is easy to desorb, resulting in limited temperature increase of the photothermal superhydrophobic adsorption material under light irradiation conditions. Summary of the Invention

[0004] Aiming at the technical problem of poor adsorption stability of superhydrophobic adsorption materials for highly viscous crude oil, the present invention proposes a photothermal superhydrophobic porous material based on ultra-light clay, its preparation method and application. The prepared photothermal superhydrophobic porous material has low cost, high photothermal conversion performance, and high oil adsorption performance.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] A preparation method of a photothermal superhydrophobic porous material based on ultra-light clay, comprising the following steps:

[0007] (1) Disperse carbon materials and ultra-light clay in distilled water in sequence to obtain a mixed solution;

[0008] (2) Add a foaming agent to the mixed solution and continuously stir until uniform foam appears in the mixed solution;

[0009] (3) Freeze-dry the mixed solution obtained in step (2) to obtain a porous material based on ultralight clay.

[0010] (4) Prepare a superhydrophobic modification solution, immerse the porous material based on ultralight clay in the superhydrophobic modification solution for hydrophobic modification to obtain a photothermal superhydrophobic porous material.

[0011] The carbon material is carbon nanotubes (CNTs), multi-walled carbon nanotubes (MWCNTs), carbon black (CB), carbon dots (CDs), graphene (GO), etc.

[0012] The ultralight clay includes all commercially available ultralight clays, and its main components are water, polypropylene microspheres, synthetic paste, plastics, etc.

[0013] The foaming agent is Triton X-100 or sodium dodecyl sulfate. In addition, it can also be other surfactants that can foam.

[0014] The mass ratio of the ultralight clay: carbon material: distilled water is 10:(0.5 - 5):(30 - 80).

[0015] The mass ratio of the distilled water to the foaming agent is 20:(1 - 2).

[0016] In step (1), the carbon material is first added to distilled water and ultrasonically dispersed for 30 - 180 min, and then the ultralight clay is added.

[0017] The freeze-drying time is 12 - 72 h.

[0018] The superhydrophobic modification solution is prepared by dissolving a superhydrophobic modifier in a solvent, and the concentration is 1 - 5 vol%; the superhydrophobic modifier is silane or fluorosilane, and the solvent is n-hexane, toluene, ethanol, tetrahydrofuran, etc.

[0019] The photothermal superhydrophobic porous material based on ultralight clay prepared by the above method.

[0020] Application of the photothermal superhydrophobic porous material in oil-water separation.

[0021] Advantages of the present invention:

[0022] Ultra-light clay has advantages such as low cost, light weight, and easy solubility in water, and is an alternative for excellent porous materials. Based on this, the present invention mixes ultra-light clay with carbon materials to form a homogeneous solution, enabling the carbon materials to firmly combine with the ultra-light clay, prepares a photothermal superhydrophobic porous material based on ultra-light clay, and can significantly increase the loading amount of carbon materials and improve the photothermal temperature of the materials. Moreover, it solves the problem that the photothermal materials in the photothermal superhydrophobic materials based on sponges prepared by methods such as impregnation, spraying, and in-situ growth are prone to desorption, thus reducing the photothermal performance of the materials. At the same time, the prepared photothermal superhydrophobic porous material based on ultra-light clay has good mechanical properties, porosity, and cycle stability, and has good development prospects in the field of adsorption and recovery of high-viscosity oil.

[0023] After the porous material prepared by the present invention is hydrophobically modified, the hydrophobic contact angle of the prepared sponge is 137°, it has good photothermal performance, the highest photothermal test temperature can reach 82.9 °C, it has potential adsorption capacity for crude oil, and as the temperature rises, the viscosity of the crude oil decreases significantly. Brief Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 The hydrophobic contact angle of the photothermal superhydrophobic porous material based on ultra-light clay prepared in Example 1.

[0026] Figure 2 The finished product diagram of the photothermal superhydrophobic porous material based on ultra-light clay prepared in Example 1.

[0027] Figure 3 The electron microscope scanning diagram of the photothermal superhydrophobic porous material based on ultra-light clay prepared in Example 1.

[0028] Figure 4 The photothermal test of the photothermal superhydrophobic porous materials based on ultra-light clay prepared in Examples 1-4.

[0029] Figure 5 The infrared camera diagram of the photothermal superhydrophobic porous materials based on ultra-light clay prepared in Examples 1-4.

[0030] Figure 6 The adsorption situation of the photothermal superhydrophobic porous material based on ultra-light clay prepared in Example 1 for n-hexane (orange liquid: n-hexane; blue liquid: water).

[0031] Figure 7 Adsorption amounts of the photothermal superhydrophobic porous material based on ultralight clay prepared in Example 1 for lubricating oil, toluene, cyclohexane, dichloromethane, and n-hexane.

[0032] Figure 8 Cyclic adsorption experiment of the photothermal superhydrophobic porous material based on ultralight clay prepared in Example 1.

[0033] Figure 9 Curve of crude oil viscosity varying with temperature.

[0034] Figure 10 Adsorption experiment of the photothermal superhydrophobic porous material based on ultralight clay prepared in Example 1 for crude oil under photothermal conditions. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] Example 1

[0037] A photothermal superhydrophobic porous material based on ultralight clay, and its preparation method includes the following steps:

[0038] (1) Weigh 0.8 g of carbon nanotubes and place them in a beaker.

[0039] (2) Take 35 mL of distilled water, add it to the above beaker, and ultrasonicate for 30 min to uniformly disperse CNTs in the distilled water.

[0040] (3) Take 10 g of ultralight clay and place it in the above CNT aqueous solution, stir for 2 h under magnetic stirring, and then continue to stir with a glass rod until the ultralight clay is uniformly dispersed in the CNT solution.

[0041] (4) Measure 2 g of Triton X-100, add it to the above uniformly dispersed ultralight clay solution, and stir with a glass rod for 6 min until foaming occurs.

[0042] (5) Transfer the above foamed solution to a polytetrafluoroethylene mold, then transfer the mold to a refrigerator at -20 °C and freeze for 24 h, and transfer the frozen product to a freeze dryer for freeze drying for 24 h to obtain a photothermal porous material based on ultralight clay.

[0043] (6) Add 30 mL of n-hexane and 300 μL of octadecyltrichlorosilane to a clean beaker. Immerse the above-mentioned photothermal foam material based on ultralight clay into the octadecyltrichlorosilane solution and soak for 12 h. After soaking, place it in an oven at 60 °C to dry, and obtain a photothermal superhydrophobic porous material based on ultralight clay.

[0044] Example 2

[0045] A photothermal superhydrophobic porous material based on ultralight clay, and its preparation method includes the following steps:

[0046] (1) Weigh 1.6 g of carbon nanotubes and place them in a beaker.

[0047] (2) Take 50 mL of distilled water and add it to the above beaker. Ultrasonicate for 60 min to uniformly disperse CNTs in the distilled water.

[0048] (3) Take 10 g of ultralight clay and place it in the above aqueous CNTs solution. Stir for 2 h under magnetic stirring, and then continue to stir with a glass rod until the ultralight clay is uniformly dispersed in the CNTs solution.

[0049] (4) Measure 2.5 g of Triton X-100 and add it to the above uniformly dispersed ultralight clay solution. Stir with a glass rod for 6 min until foaming occurs.

[0050] (5) Transfer the above foamed solution to a polytetrafluoroethylene mold, then transfer the mold to a refrigerator at -20 °C and freeze for 12 h. Transfer the frozen product to a freeze dryer and freeze-dry for 24 h to obtain a photothermal porous material based on ultralight clay.

[0051] (6) Add 30 mL of n-hexane and 300 μL of octadecyltrichlorosilane to a clean beaker. Immerse the above-mentioned photothermal foam material based on ultralight clay into the octadecyltrichlorosilane solution and soak for 12 h. After soaking, place it in an oven at 60 °C to dry, and obtain a photothermal superhydrophobic porous material based on ultralight clay.

[0052] Example 3

[0053] A photothermal superhydrophobic porous material based on ultralight clay, and its preparation method includes the following steps:

[0054] (1) Weigh 2.4 g of carbon nanotubes and place them in a beaker.

[0055] (2) Take 60 mL of distilled water and add it to the above beaker. Ultrasonicate for 30 min to uniformly disperse CNTs in the distilled water.

[0056] (3) Weigh 10 g of ultra-light clay and place it in the above-mentioned CNTs aqueous solution. Stir it for 2 h under magnetic stirring, and then continue to stir with a glass rod until the ultra-light clay is evenly dispersed in the CNTs solution.

[0057] (4) Measure 3 g of Triton X-100 and add it to the above-mentioned evenly dispersed ultra-light clay solution. Stir it with a glass rod for 6 min until foaming occurs.

[0058] (5) Transfer the above-mentioned foamed solution to a polytetrafluoroethylene mold, then transfer the mold to a refrigerator at -20 °C and freeze it for 12 h. Transfer the frozen product to a freeze dryer and freeze-dry it for 24 h to obtain a photothermal porous material based on ultra-light clay.

[0059] (6) Add 30 mL of n-hexane and 300 μL of octadecyltrichlorosilane to a clean beaker. Immerse the above-mentioned photothermal foam material based on ultra-light clay in the octadecyltrichlorosilane solution and soak it for 24 h. After soaking, place it in an oven at 60 °C and dry it to obtain a photothermal superhydrophobic porous material based on ultra-light clay.

[0060] Example 4

[0061] A photothermal superhydrophobic porous material based on ultra-light clay, and its preparation method includes the following steps:

[0062] (1) Weigh 3.6 g of carbon nanotubes and place them in a beaker.

[0063] (2) Take 80 mL of distilled water and add it to the above-mentioned beaker. Ultrasonic it for 30 min to make the CNTs evenly dispersed in the distilled water.

[0064] (3) Take 10 g of ultra-light clay and place it in the above-mentioned CNTs aqueous solution. Stir it for 2 h under magnetic stirring, and then continue to stir with a glass rod until the ultra-light clay is evenly dispersed in the CNTs solution.

[0065] (4) Measure 4 g of Triton X-100 and add it to the above-mentioned evenly dispersed ultra-light clay solution. Stir it with a glass rod for 6 min until foaming occurs.

[0066] (5) Transfer the above-mentioned foamed solution to a polytetrafluoroethylene mold, then transfer the mold to a refrigerator at -20 °C and freeze it for 12 h. Transfer the frozen product to a freeze dryer and freeze-dry it for 24 h to obtain a photothermal porous material based on ultra-light clay.

[0067] (6) Add 30 mL of n-hexane and 300 μL of octadecyltrichlorosilane to a clean beaker. Immerse the above-mentioned photothermal foam material based on ultra-light clay in the octadecyltrichlorosilane solution and soak it for 16 h. After soaking, place it in an oven at 60 °C and dry it to obtain a photothermal superhydrophobic porous material based on ultra-light clay.

[0068] Example 5

[0069] A photothermal superhydrophobic porous material based on ultra-light clay, and its preparation method includes the following steps:

[0070] (1) Weigh 5 g of multi-walled carbon nanotubes and place them in a beaker.

[0071] (2) Take 80 mL of distilled water, add it to the above beaker, and ultrasonicate for 30 min to uniformly disperse MWCNTs in the distilled water.

[0072] (3) Take 10 g of ultra-light clay and place it in the above MWCNTs aqueous solution, stir for 2 h under magnetic stirring, and then continue to stir with a glass rod until the ultra-light clay is uniformly dispersed in the MWCNTs solution.

[0073] (4) Measure 6 g of Triton X-100, add it to the above uniformly dispersed ultra-light clay solution, and stir with a glass rod for 3 min until foaming occurs.

[0074] (5) Transfer the above foamed solution to a polytetrafluoroethylene mold, then transfer the mold to a refrigerator at -20 °C and freeze for 24 h. Transfer the frozen product to a freeze dryer and freeze-dry for 72 h to obtain a photothermal porous material based on ultra-light clay.

[0075] (6) Add 50 mL of toluene and 2.5 mL of octadecyltrichlorosilane to a clean beaker, immerse the above photothermal foam material based on ultra-light clay in the octadecyltrichlorosilane solution, and soak for 16 h. After soaking, place it in an oven at 60 °C and dry it to obtain a photothermal superhydrophobic porous material based on ultra-light clay.

[0076] Example 6

[0077] A photothermal superhydrophobic porous material based on ultra-light clay, and its preparation method includes the following steps:

[0078] (1) Weigh 0.5 g of graphene and place it in a beaker.

[0079] (2) Take 30 mL of distilled water, add it to the above beaker, and ultrasonicate for 180 min to uniformly disperse GO in the distilled water.

[0080] (3) Take 10 g of ultra-light clay and place it in the above GO aqueous solution, stir for 2 h under magnetic stirring, and then continue to stir with a glass rod until the ultra-light clay is uniformly dispersed in the GO solution.

[0081] (4) Measure 1.5 g of sodium dodecyl sulfate, add it to the above uniformly dispersed ultra-light clay solution, and stir with a glass rod for 6 min until foaming occurs.

[0082] (5) Transfer the above foamed solution to a polytetrafluoroethylene mold, then transfer the mold to a refrigerator at -20 °C and freeze for 12 h. Transfer the frozen product to a freeze dryer and freeze-dry for 12 h to obtain a photothermal porous material based on ultra-light clay.

[0083] (6) Add 50 mL of tetrahydrofuran and 1 mL of octadecyltrichlorosilane to a clean beaker. Immerse the above photothermal foam material based on ultra-light clay in the octadecyltrichlorosilane solution and soak for 12 h. After soaking, place it in an oven at 60 °C and dry to obtain a photothermal superhydrophobic porous material based on ultra-light clay.

[0084] Test Example

[0085] Take the photothermal superhydrophobic porous material based on ultra-light clay prepared in Example 1 for hydrophobic contact angle test and photothermal test. The results of morphological structure characterization are as follows:

[0086] 1. Contact angle and morphological structure characterization

[0087] As Figure 1 shown, after hydrophobic modification with octadecyltrichlorosilane, the photothermal superhydrophobic porous material based on ultra-light clay shows a good hydrophobic angle (137°). As Figure 2 shown in the schematic diagram of the finished product, the prepared porous material has the advantage of being ultra-light, which is beneficial for subsequent applications. As Figure 3 shown, the photothermal superhydrophobic porous material based on ultra-light clay formed by adding CNTs and foaming agent and continuous stirring is filled with pore structure inside (pore diameter is about 100 - 200 μm). The advantages of pore structure, good hydrophobicity and light weight are more conducive to the adsorption and recovery of high-viscosity crude oil.

[0088] 2. Photothermal test

[0089] As Figure 4 shown, the surface temperature of the photothermal superhydrophobic porous material based on ultra-light clay in Examples 1 - 4 can reach up to 82.9 °C under the irradiation of a xenon lamp with an illumination intensity of 1 kW / m 2 . Figure 4 And Figure 5 confirmed its good photothermal property, which is beneficial for realizing the adsorption of high-viscosity crude oil.

[0090] Due to its good hydrophobicity, when the porous material is placed in a mixed solution of n-hexane and water, the photothermal superhydrophobic porous material based on ultra-light clay can selectively adsorb n-hexane without adsorbing water ( Figure 6 ), realizing selective adsorption. The adsorption capacity of the photothermal superhydrophobic porous material based on ultra-light clay for various oils was tested. As Figure 7As shown, its adsorption range is 15 - 30 g / g. Figure 8 It is confirmed that the prepared ultra-light clay-based photothermal superhydrophobic porous material has good cycle stability in the adsorption experiment.

[0091] 3. Crude oil adsorption experiment

[0092] The viscosity of crude oil decreases with the increase of temperature. As Figure 9 shown, at 24°C, its viscosity is 1.3×10 5 mpa·s. When the temperature rises to 83°C, the viscosity of crude oil decreases to 10 mpa·s. The decrease in the viscosity of crude oil will effectively improve the adsorption and recovery efficiency of the material for crude oil. As Figure 10 shown, the ultra-light clay-based photothermal superhydrophobic porous material in Example 1, under the irradiation of a xenon lamp with an illumination intensity of 1 kw / m 2 and with the assistance of a peristaltic pump, crude oil begins to be recovered into the right beaker after 6 minutes. When the adsorption experiment proceeds to 20 minutes, the recovered amount of crude oil reaches 20 g, achieving effective adsorption and recovery of high-viscosity crude oil. This is because the prepared ultra-light clay-based photothermal superhydrophobic porous material has good photothermal conversion performance, which makes its surface temperature rise under illumination, further causing the temperature of crude oil to rise and the viscosity to decrease.

[0093] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a photothermal superhydrophobic porous material based on ultra-light clay, characterized in that, It includes the following steps: (1) Disperse carbon materials and ultralight clay in distilled water in sequence to obtain a mixed solution; (2) Add a foaming agent to the mixed solution and continuously stir to foam; (3) Lyophilize the foamed mixed solution in step (2) to obtain a porous material based on ultralight clay; (4) Prepare a superhydrophobic modification solution, immerse the porous material based on ultralight clay in the superhydrophobic modification solution for hydrophobic modification to obtain a photothermal superhydrophobic porous material.

2. The preparation method of the photothermal superhydrophobic porous material based on ultra-light clay according to claim 1, characterized in that, The carbon material is any one or combination of carbon nanotubes, carbon black, carbon dots and graphene.

3. The preparation method of the photothermal superhydrophobic porous material based on ultra-light clay according to claim 1, characterized in that, The foaming agent is Triton X-100 or sodium dodecyl sulfate.

4. The preparation method of the photothermal superhydrophobic porous material based on ultra-light clay according to claim 1, characterized in that, The mass ratio of the ultralight clay: carbon material: distilled water is 10:(0.5 - 5):(30 - 80).

5. The preparation method of the photothermal superhydrophobic porous material based on ultra-light clay according to claim 1, characterized in that, The mass ratio of the distilled water to the foaming agent is 20:(1 - 2).

6. The preparation method of the photothermal superhydrophobic porous material based on ultra-light clay according to claim 1, characterized in that, In step (1), add the carbon material to the distilled water and ultrasonically disperse it for 30 - 180 min, and then add the ultralight clay.

7. The preparation method of the photothermal superhydrophobic porous material based on ultra-light clay according to claim 1, characterized in that, The time of lyophilization is 12 - 72 h.

8. The preparation method of the photothermal superhydrophobic porous material based on ultra-light clay according to claim 1, characterized in that, The superhydrophobic modification solution is prepared by dissolving a hydrophobic modifier in a solvent, and the concentration is 1 - 5 vol%; the hydrophobic modifier is silane, and the solvent is n-hexane, toluene, ethanol or tetrahydrofuran.

9. A photothermal superhydrophobic porous material based on ultra-light clay prepared by the method according to any one of claims 1-8.

10. Application of the photothermal superhydrophobic porous material based on ultra-light clay according to claim 9 in oil-water separation.

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