A high-stability underwater super-oleophobic photothermal fabric and its preparation method and application

Abstract

The present invention discloses a high-stability underwater super-oleophobic photothermal fabric, and a preparation method and application thereof. The present invention prepares an underwater super-oleophobic photothermal fabric by depositing carbon black nanoparticles of a photothermal material and calcium alginate hydrogel, an underwater super-oleophobic material, on a cotton fabric substrate. The application is: assembling the underwater super-oleophobic photothermal fabric and polyethylene foam from top to bottom in the form of a two-dimensional water channel to form a solar interface water evaporation device. The entire preparation process of the high-stability underwater super-oleophobic photothermal material of the present invention has the advantages of low raw material price, simple and mild preparation process, and easy to scale up production. In terms of performance, it simultaneously achieves efficient light absorption and underwater super-oleophobic function, and can withstand harsh environments such as acidic, alkaline, salt water environment, ultrasound, high temperature treatment, etc., and can be used for solar-driven oil-containing water purification.

Description

Technical Field

[0001] The present invention relates to the field of environmental functional materials, and in particular to a high-stability underwater super oleophobic photothermal fabric, a preparation method thereof, and applications thereof. Background Art

[0002] Against the backdrop of achieving carbon peak and carbon neutrality, solar interfacial water evaporation, as a clean energy-driven, environmentally friendly water treatment technology, holds broad promise in applications such as seawater desalination and wastewater treatment. Photothermal materials absorb solar energy and convert it into heat, accelerating water evaporation and thus separating water molecules from pollutants. Designing photothermal materials with superior performance is key to achieving effective solar water evaporation.

[0003] Oil, a common contaminant in aquatic environments, can adhere to photothermal materials, hindering water transport and thus inhibiting the evaporation performance of solar water evaporation devices. Highly stable underwater superoleophobic photothermal materials can successfully resist oil contamination in oily waters, enabling solar-driven water purification. This holds great promise for practical applications, yet research on this topic remains limited. Summary of the Invention

[0004] The present invention provides a highly stable underwater superoleophobic photothermal fabric, its preparation method, and its application. The fabric is prepared by depositing carbon black nanoparticles (a photothermal material) and calcium alginate hydrogel (an underwater superoleophobic material) onto a cotton fabric substrate. This fabric is then embedded in a polyethylene foam insulation material in the form of two-dimensional water channels to form a solar interfacial water evaporation device, which can be used for solar-driven purification of oily water bodies.

[0005] 1. A method for preparing a highly stable underwater superoleophobic photothermal fabric, comprising the following steps:

[0006] (1) Carbon black nanoparticles and sodium alginate were dissolved in deionized water, and then magnetically stirred for 0.5 to 10 h and ultrasonically treated for 0.5 to 10 h to obtain a uniformly dispersed carbon black suspension.

[0007] (2) Soak the cotton fabric in the suspension for 0.5 to 120 minutes, then transfer the cotton fabric to a CaCl2 solution and soak for 0.5 to 120 minutes to achieve CaCl2 2+ After the reaction, the product was thoroughly washed with deionized water and dried naturally for 1 to 72 hours to obtain a highly stable underwater superoleophobic photothermal fabric.

[0008] In step (1), the mass fraction of carbon black in the carbon black suspension is 0.01 to 10.0 wt% (more preferably 0.05 to 5%), and the mass fraction of sodium alginate is 0.01 to 10.0 wt% (more preferably 0.05 to 5%).

[0009] Preferably, the magnetic stirring time is 0.5 to 5 h, and the ultrasonic treatment time is 0.5 to 5 h.

[0010] In step (2), the mass fraction of CaCl2 in the CaCl2 solution is 0.1 to 30 wt% (more preferably 1 to 10 mol / L).

[0011] Preferably, the immersion time in the carbon black suspension is 1 to 60 minutes; the immersion time in the CaCl2 solution is 1 to 60 minutes; and the natural drying is drying in the air for 8 to 24 hours.

[0012] 2. Application of oil-resistant solar interfacial water evaporation devices based on highly stable underwater superoleophobic photothermal fabrics

[0013] The underwater superoleophobic photothermal fabric is embedded in the polyethylene foam insulation material in the form of two-dimensional water channels to form a solar-driven oil-resistant interfacial water evaporation device.

[0014] During the evaporation test, 1kW m -2 Simulated sunlight was provided by a solar simulator (CEL-AAAS50, Aulight). The room temperature was maintained at 24-26°C and the humidity was 45%-65%. The oil-resistant interfacial water evaporation device was placed on a beaker of water. The weight change during evaporation was recorded using an electronic balance, and the evaporation rate was calculated to examine the device's evaporation performance.

[0015] When studying the oil-resistant performance of the device, 1 mL of soybean oil was injected into a beaker using a syringe, the weight change was recorded using an electronic balance, and the evaporation rate was calculated to examine the evaporation performance of the device in oil-containing water.

[0016] The stability of the underwater superoleophobic photothermal fabric in a variety of typical harsh environments was tested. Among them, the acidic environment (pH = 1), alkaline environment (pH = 11) and salt water environment (0.5M NaCl) were provided by aqueous solutions of HCl, NaOH and NaCl, respectively, and the fabric was immersed in these solutions for 48 hours; during ultrasonic treatment, the fabric was placed in deionized water and treated with an ultrasonic cleaner for 30 minutes; during high temperature treatment, the fabric was treated in an 80°C oven for 3 hours. The fabrics treated in these harsh environments were then subjected to relevant tests, including their absorption spectrum in the sunlight band, underwater soybean oil contact angle, and solar evaporation rate in oil-containing water bodies. The method was the same as the previous test method for untreated fabrics.

[0017] When examining the device's water purification performance, the device is placed in a beaker containing oily wastewater or dye-containing wastewater. The steam generated under simulated sunlight condenses into liquid on the inner wall of a large beaker used to collect condensed water. The TOC concentration of the wastewater and condensed water before and after evaporation is measured using a total organic carbon analyzer, and the dye absorbance is measured using a UV-visible-near-infrared spectrophotometer.

[0018] The present invention assembles underwater superoleophobic photothermal fabric and polyethylene foam in a two-dimensional water channel from top to bottom to form a solar interfacial water evaporation device. The entire preparation process of the high-stability underwater superoleophobic photothermal material of this invention offers advantages such as low raw material costs, a simple and gentle preparation process, and ease of scalable production. It simultaneously achieves efficient light absorption and underwater superoleophobicity, and is resistant to harsh environments such as acidic, alkaline, and saline environments, ultrasound, and high-temperature treatments. It can be used for solar-driven purification of oily water bodies.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) By loading carbon black nanoparticles and calcium alginate hydrogel on cotton fabric, a highly stable underwater superoleophobic photothermal fabric can be prepared, which has the advantages of low raw material price, simple and mild preparation process, and easy to scale up production.

[0021] (2) It achieves both efficient light absorption and underwater superoleophobicity in terms of performance, and can be used for solar-driven purification of oily water bodies.

[0022] (3) The interfacial water evaporation device based on underwater superoleophobic photothermal fabric successfully purified TOC in oily wastewater and dyes in simulated dye wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 These are the actual pictures and SEM pictures of the underwater superoleophobic photothermal fabric.

[0024] Figure 2 This is the UV-visible-near-infrared absorption spectrum of the underwater superoleophobic photothermal fabric and its infrared image when it is in a stable state under light.

[0025] Figure 3 Underwater soybean oil contact angle of underwater superoleophobic photothermal fabric.

[0026] Figure 4 It is an oil-resistant solar interfacial water evaporation device based on underwater superoleophobic photothermal fabric (placed on a beaker).

[0027] Figure 5 is the evaporation rate of the device in oily and non-oiled water bodies. The results show that the performance of the device is similar in the two water bodies, confirming the oil-resistant effect of the device.

[0028] Figure 6 The UV-visible-near-infrared absorption spectra, underwater soybean oil contact angles, and solar evaporation rates of the corresponding evaporation devices of underwater superoleophobic photothermal fabrics after treatment in various typical harsh environments are presented.

[0029] Figure 7 The device's purification effect on oily water and simulated dye wastewater. DETAILED DESCRIPTION

[0030] The present invention is further described in detail through the following examples with reference to the accompanying drawings.

[0031] (1) Processing process of the present invention

[0032] A method for preparing a highly stable underwater superoleophobic photothermal fabric. First, carbon black nanoparticles (mass fraction of 0.2 wt% in carbon black suspension) and sodium alginate (mass fraction of 1 wt% in carbon black suspension) were dissolved in deionized water, and then subjected to magnetic stirring for 1 h and ultrasonic treatment for 1 h to obtain a uniformly dispersed carbon black suspension. Cotton fabric was soaked in the suspension for 10 min, and then the cotton fabric was transferred to a CaCl2 aqueous solution (5 wt%) and soaked for 10 min to achieve CaCl2 2+ After the reaction, the super-oleophobic photothermal fabric with high stability was obtained by thorough washing with deionized water and drying naturally for 12 hours. Figure 1 Optical photographs and SEM images of the fabric are shown, the latter demonstrating that the surface roughness helps promote the wettability of the fabric (underwater superoleophobicity).

[0033] like Figure 2 As shown in the figure, the light absorption rate of the fabric (in wet state) was measured by UV-visible-near infrared absorption spectrophotometer, and the result was 93.6%; at 1 kW m -2 Under the simulated sunlight, the temperature of the fabric can be raised from room temperature to about 70°C, showing its excellent photothermal properties. The surface wettability of the fabric was tested using a video contact angle meter. The underwater contact angle of the fabric to soybean oil was 152.4°, indicating underwater superoleophobicity. Figure 3 shown.

[0034] As an application, the fabric (2×9 cm 2 ) is embedded in polyethylene foam (thickness 1.5cm) thermal insulation material in the form of a two-dimensional water channel, controlling the area of ​​the photothermal fabric that can receive sunlight to 2×2cm 2 , forming a solar-driven oil-resistant interfacial water evaporation device, such as Figure 4 shown.

[0035] During the evaporation test, 1kW m -2Simulated sunlight was provided by a solar simulator (CEL-AAAS50, Aulight). The room temperature was maintained at 24-26°C and the humidity was 45%-65%. The oil-resistant interfacial water evaporation device was placed on a beaker of water. The weight change during evaporation was recorded using an electronic balance, and the evaporation rate was calculated to examine the device's evaporation performance.

[0036] When studying the oil resistance of the device, 1 mL of soybean oil was injected into a beaker using a syringe, and the weight change was recorded using an electronic balance. The evaporation rate was calculated to examine the evaporation performance of the device in oil-containing water. The results are as follows: Figure 5 The evaporation rates of the device in oil-free water and oil-containing water are 1.44 kg / m 2 / h and 1.43kg / m 2 / h, and the evaporation efficiency is about 85%.

[0037] The stability of the underwater superoleophobic photothermal fabric in a variety of typical harsh environments was tested. Among them, the acidic environment (pH = 1), alkaline environment (pH = 11) and saline environment (0.5M NaCl) were provided by aqueous solutions of HCl, NaOH and NaCl, respectively, and the fabric was immersed in these solutions for 48 hours; during ultrasonic treatment, the fabric was placed in deionized water and treated with an ultrasonic cleaner for 30 minutes; during high-temperature treatment, the fabric was treated in an 80°C oven for 3 hours. The fabrics treated in these harsh environments were then subjected to relevant tests, including their absorption spectrum in the sunlight band, underwater soybean oil contact angle, and solar evaporation rate in oil-containing water bodies. The methods were the same as those for the untreated fabrics. The results are as follows Figure 6 As shown, the solar absorption performance, underwater superoleophobic properties and solar evaporation rate of the fabric do not change significantly, that is, it has high stability.

[0038] When testing the device's water purification performance, the device was placed in a beaker containing oily wastewater or dye-containing wastewater. The steam generated under simulated sunlight condensed into liquid on the inner wall of a large beaker used to collect condensed water. The TOC concentration of the wastewater and condensed water before and after evaporation was measured using a total organic carbon analyzer, and the dye absorbance was measured using a UV-Vis-NIR spectrophotometer. The results are as follows: Figure 7 As shown in the figure, the TOC removal rate of oily water is as high as 99.7%, and Rhodamine B and methylene blue in dye-containing wastewater are also successfully removed.

[0039] (2) The effect obtained by this example

[0040] This example realizes the preparation and application of a highly stable underwater superoleophobic photothermal fabric. When it is applied to solar interface water evaporation, the evaporation performance is excellent and is not affected by oil. After being treated in a variety of harsh environments such as acidic environment (pH=1), alkaline environment (pH=11), salt water environment (0.5M NaCl), ultrasonic treatment, high temperature (80°C), etc., the solar light absorption performance and underwater superoleophobic properties of the fabric remain stable, and the solar evaporation rate in oily wastewater does not change significantly compared with before treatment. In addition, the evaporator based on this fabric has excellent purification effects on oily wastewater and simulated dye wastewater, and has application prospects in water treatment.

Claims

1. A method for preparing a high-stability underwater super oleophobic photothermal fabric, characterized in that: The following steps are involved: (1) dissolving carbon black nanoparticles and sodium alginate in water, performing magnetic stirring and ultrasonic treatment to obtain a uniformly dispersed carbon black suspension; (2) Soak the cotton fabric in the carbon black suspension for 0.5 to 120 min, then transfer the cotton fabric to the CaCl2 solution and soak it for 0.5 to 120 min to achieve CaCl2 2+ Cross-linking, washing with water after the reaction, and naturally drying to obtain a highly stable underwater superoleophobic photothermal fabric; The mass fraction of CaCl2 in the CaCl2 aqueous solution is 0.1 to 30 wt%.

2. The preparation method according to claim 1, characterized in that In step (1), magnetic stirring is performed for 0.5 to 10 hours; Ultrasonic treatment for 0.5 to 10 hours.

3. The preparation method according to claim 1, characterized in that In step (1), the mass fraction of carbon black in the carbon black suspension is 0.01 to 10.0 wt%, and the mass fraction of sodium alginate is 0.01 to 10.0 wt%.

4. The preparation method according to claim 1, characterized in that In step (2), the mixture is dried naturally for 1 to 72 hours.

5. A high-stability underwater superoleophobic photothermal fabric prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the high-stability underwater superoleophobic photothermal fabric according to claim 5 in preparing a solar-driven oil-resistant interfacial water evaporation device.

7. The use according to claim 6, characterized in that include: The high-stability underwater superoleophobic photothermal fabric is embedded in the polyethylene foam insulation material in the form of two-dimensional water channels to form a solar-driven oil-resistant interfacial water evaporation device.

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