A method for preparing a foaming aerogel elastomer with integrated photothermal and hydrophilic design

Abstract

The present invention discloses a method for preparing a foaming aerogel elastomer with a photothermal hydrophilic integrated design, and the steps are as follows: (1) adding copper acetylacetonate to a polyether polyol and stirring to obtain a uniform dispersion; (2) quickly adding diphenylmethane diisocyanate to the dispersion, and quickly and vigorously stirring with a glass rod, and foaming and aging at a constant temperature of 30°C for 4 hours; (3) cutting and shaping the sample obtained in step (2) and placing it in a (NH4)2S solution with a concentration of 14wt% to soak and react for 12 hours, repeatedly squeezing and washing the unreacted raw materials after the reaction is completed, and drying to obtain a foaming aerogel elastomer. The integrated design of the present application realizes the perfect unification of the photothermal layer and the hydrophilic layer, successfully suppressing the overflow of salt during the evaporation process; and at the same time, it also solves the problem of mechanical stability of the photothermal evaporator material.

Description

Technical Field

[0001] The invention relates to the field of seawater desalination, and in particular to a method for preparing a foaming aerogel elastomer with a photothermal-hydrophilic integrated design. Background Art

[0002] Industrial production, environmental pollution, and population explosion have led to a serious shortage of natural freshwater resources in many countries. The ocean, as the most important reservoir on Earth, has a salinity of about 35‰. Desalination of seawater is the most ideal solution to this problem. Solar evaporators use green solar energy to obtain a large amount of steam, which not only meets the requirements of green development, but also solves the problem of resource shortage. Traditional technologies such as multi-stage flash evaporation, reverse osmosis, and electrodialysis are based on fossil energy and do not conform to the concept of green production.

[0003] Since the beginning of the 21st century, people have gradually mastered the positioning of solar heat and expanded it to power generation, sterilization, production and other technical fields, providing new desalination solutions for high-efficiency steam. Zhang Zhe's team at Tianjin University of Commerce prepared a double-layer structure by calcination and adhesion. The upper layer uses copper carbide doped biochar to fix sunlight and increase the photothermal conversion capacity through the local surface plasma resonance effect. The lower layer is constructed of felt fabric. The larger spatial network structure ensures sufficient water transportation and has good salt resistance while reaching 1.571kg·m -2 ·h -1 The evaporation rate of 2D photothermal paper was reduced by 1.53 kg·m in the test. -2 ·h -1 The evaporation rate exceeds the thermodynamic upper limit of the 2D evaporator. Zheng Yanyan's team from North Sichuan Medical College successfully developed an evaporator based on the integration of copper dendrites and abundant copper oxide nanowires. With a large photothermal evaporation area and efficient water transfer characteristics, the solar water evaporation system can still achieve an amazing evaporation rate of 87.8% and 1.40kg·m even after multiple cycles. -2 ·h -1 In addition, the continuous release of copper ions effectively inhibits bacterial growth, ensuring the quality and biosafety of pure water in practical applications. The Tang Sheng team of Jiangsu University of Science and Technology integrated nano-CuFe2O4 and plasma Cu in graphite porous carbon nanofibers through electrospinning, gel crosslinking and other methods, and finally embedded them in melamine sponge, so that the evaporator achieved a maximum of 1.76kg·m -2 ·h -1 steam production rate.

[0004] However, the above schemes still have some shortcomings, such as: the photothermal layer is separated from the hydrophilic layer, the water transfer effect is poor, and the evaporation rate is low; the synthesis process often uses expensive reagents or complex synthesis methods or harsh treatment methods; some schemes use membranes as the main light absorption and evaporation materials, which have limited mechanical stability and are prone to salt accumulation.

[0005] Based on this, the technical solution of the present application is proposed. Summary of the invention

[0006] The solution of the present invention is to introduce a copper source into a self-foaming polyurethane elastomer. The integrated design achieves a perfect unification of the photothermal layer and the hydrophilic layer, successfully suppressing the overflow of salt during the evaporation process; at the same time, it also solves the problem of mechanical stability of the photothermal evaporator material.

[0007] The present invention relates to a method for preparing a foamed aerogel elastomer with a photothermal-hydrophilic integrated design, and the steps are as follows:

[0008] (1) adding copper acetylacetonate to polyether polyol and stirring to obtain a uniform dispersion;

[0009] (2) quickly adding diphenylmethane diisocyanate to the dispersion, stirring rapidly and vigorously with a glass rod, and foaming and aging at a constant temperature of 30° C. for 4 h;

[0010] (3) Cutting and shaping the sample obtained in step (2), soaking it in a 14 wt% (NH4)2S solution for reaction for 12 h, and after the reaction is completed, repeatedly squeezing and washing the unreacted raw materials, and drying to obtain a foamed aerogel elastomer.

[0011] More preferably, the ratio of polyether polyol to copper acetylacetonate in step (1) is 10:0.5-3 in ml:g.

[0012] More preferably, the volume ratio of diphenylmethane diisocyanate to polyether polyol in step (2) is 1:2.

[0013] Application of the foamed aerogel elastomer obtained by any of the above preparation methods in photothermal evaporator materials.

[0014] The present invention has the following beneficial effects:

[0015] (1) The integration of the photothermal layer and the hydrophilic channel is achieved, which improves the overall mechanical stability;

[0016] (2) The synthesis process is mild, the operation is simple, and it is easy to prepare large-scale products;

[0017] (3) CuS is used as the light absorbing material. The roughness of the aerogel surface not only enhances the light absorption, but also increases the effective evaporation area. The evaporation rate reaches 2.05 kg·m-2 ·h -1 . BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 As shown in the figure: (a) actual image of polyurethane aerogel, (b) photo of hydrophilicity of aerogel, salt dissolution experiment (c), evaporation experiment in salt water (d).

[0019] Figure 2 (ac) SEM images of pure polyurethane aerogel, CuS, and photothermal polyurethane aerogel. Stress-strain experiment (d). Photothermal cycle stability (e).

[0020] Figure 3 (ac) are the actual pictures of comparative examples 1, 2 and 3. DETAILED DESCRIPTION

[0021] In order to demonstrate the essential features and significant improvements of the present invention, the following examples are used to further illustrate the implementation methods and effects.

[0022] The polyether polyol was produced by Yadong, model 6401-01, and diphenylmethane diisocyanate was produced by Huntsman. Copper acetylacetonate and 14 wt% (NH4)2S solution were provided by Shanghai MacLean Biochemical Technology Co., Ltd.

[0023] Embodiment one:

[0024] The preparation method of the photothermal hydrophilic integrated self-foaming aerogel elastomer comprises the following steps:

[0025] a. Add 1g of copper acetylacetonate to 10ml of polyether polyol and stir for 10min to obtain a uniform dispersion.

[0026] b. Quickly add 5 ml of diphenylmethane diisocyanate into the dispersion, stir rapidly and vigorously with a glass rod for 10 seconds, and then place it at 30°C for constant temperature foaming for 4 hours.

[0027] c. After the sample is cut and shaped, it is placed in 30 ml of 14 wt% (NH4)2S solution and soaked for 12 hours. After the reaction is completed, the unreacted raw materials are repeatedly squeezed and washed. After drying, a hydrophilic polyurethane aerogel with excellent photothermal properties can be obtained, such as Figure 1 As shown in a.

[0028] When water droplets were placed on the surface of a working evaporator, they were found to be absorbed within 30 milliseconds ( Figure 1 b). The salts are placed on the surface of the evaporator and will dissolve again in the original solution due to capillary action ( Figure 1 c). In the brine evaporation experiment, the good water channel in the evaporator effectively suppressed the overflow of salt ( Figure 1 d).

[0029] like Figure 2 As shown, the synthesized polyurethane aerogel retains the porous structure during foaming ( Figure 2 a), which provides ample water supply channels for surface evaporation. CuS is fixed inside the foamed fiber to locate solar energy, effectively avoiding performance degradation after repeated use ( Figure 2 b, 2c). The integrated design of photothermal and hydrophilic makes the evaporator have excellent mechanical stability. In the stress-strain experiment, the strain was fixed at 90% and compressed repeatedly for 10 cycles, and the plastic deformation was less than 1% ( Figure 2 d). After the cycle, the evaporator rate is stable and there is no obvious downward trend ( Figure 2 e).

[0030] Embodiment 2:

[0031] The preparation method of the photothermal hydrophilic integrated self-foaming aerogel elastomer comprises the following steps:

[0032] a. Add 0.5 g of copper acetylacetonate to 10 ml of polyether polyol and stir for 10 min to obtain a uniform dispersion.

[0033] b. Quickly add 5 ml of diphenylmethane diisocyanate into the dispersion, stir rapidly and vigorously with a glass rod for 10 seconds, and then place it at 30°C for constant temperature foaming for 4 hours.

[0034] c. After the sample is cut and shaped, it is placed in 30 ml of 14 wt% (NH4)2S solution and soaked for 12 hours. After the reaction is completed, the unreacted raw materials are repeatedly squeezed and washed.

[0035] Embodiment three:

[0036] The preparation method of the photothermal hydrophilic integrated self-foaming aerogel elastomer comprises the following steps:

[0037] a. Add 2g of copper acetylacetonate to 10ml of polyether polyol and stir for 10min to obtain a uniform dispersion.

[0038] b. Quickly add 5 ml of diphenylmethane diisocyanate into the dispersion, stir rapidly and vigorously with a glass rod for 10 seconds, and then place it at 30°C for constant temperature foaming for 4 hours.

[0039] c. After the sample is cut and shaped, it is placed in 30 ml of 14 wt% (NH4)2S solution and allowed to react for 12 hours. After the reaction is completed, the unreacted raw materials are repeatedly squeezed and washed. After drying, a hydrophilic polyurethane aerogel with excellent photothermal properties is obtained.

[0040] Embodiment 4:

[0041] The preparation method of the photothermal hydrophilic integrated self-foaming aerogel elastomer comprises the following steps:

[0042] a. Add 3g of copper acetylacetonate to 10ml of polyether polyol and stir for 10min to obtain a uniform dispersion.

[0043] b. Quickly add 5 ml of diphenylmethane diisocyanate into the dispersion, stir rapidly and vigorously with a glass rod for 10 seconds, and then place it at 30°C for constant temperature foaming for 4 hours.

[0044] c. After the sample is cut and shaped, it is placed in 30 ml of 14 wt% (NH4)2S solution and allowed to react for 12 hours. After the reaction is completed, the unreacted raw materials are repeatedly squeezed and washed. After drying, a hydrophilic polyurethane aerogel with excellent photothermal properties is obtained.

[0045] Table 1 shows the evaporation rate of the hydrophilic polyurethane aerogel in Examples 1-4

[0046] Example Ratio (ml:g) <![CDATA[Evaporation rate (kg·m -2 ·h -1 )]]> Embodiment 1 10：1 2.05 Embodiment 2 10：0.5 1.49 Embodiment 3 10：2 1.70 Embodiment 4 10：3 1.40

[0047] It can be seen that the difference between Examples 1, 2, 3 and 4 is that the masses of copper acetylacetonate added during foaming are different. According to repeated experiments, it is found that when the ratio is 10:1 (ml:g), the evaporator rate reaches the highest.

[0048] Comparative Example 1 ( Figure 3 a):

[0049] (1) Add 1 g of copper stearate to 10 ml of polyether polyol and stir for 10 min to obtain a uniform dispersion.

[0050] (2) Quickly add 5 ml of diphenylmethane diisocyanate into the dispersion, stir rapidly and vigorously with a glass rod for 10 seconds, and then place at 30°C for constant temperature foaming for 4 hours.

[0051] (3) After cutting, the sample is placed in 30 ml of 14 wt% (NH4)2S solution and soaked for 12 hours. After the reaction is completed, the unreacted raw materials are repeatedly squeezed and washed.

[0052] Comparative Example 2 ( Figure 3 b):

[0053] (1) Add 1 g of copper sulfate to 10 ml of polyether polyol and stir for 10 min to obtain a uniform dispersion.

[0054] (2) Quickly add 5 ml of diphenylmethane diisocyanate into the dispersion, stir rapidly and vigorously with a glass rod for 10 seconds, and then place at 30°C for constant temperature foaming for 4 hours.

[0055] (3) After cutting, the sample is placed in 30 ml of 14 wt% (NH4)2S solution and soaked for 12 hours. After the reaction is completed, the unreacted raw materials are repeatedly squeezed and washed.

[0056] Comparative Example 3 ( Figure 3 c):

[0057] (1) Add 1 g of copper nitrate to 10 ml of polyether polyol and stir for 10 min to obtain a uniform dispersion.

[0058] (2) Quickly add 5 ml of diphenylmethane diisocyanate into the dispersion, stir rapidly and vigorously with a glass rod for 10 seconds, and then place at 30°C for constant temperature foaming for 4 hours.

[0059] (3) After cutting, the sample is placed in 30 ml of 14 wt% (NH4)2S solution and soaked for 12 hours. After the reaction is completed, the unreacted raw materials are repeatedly squeezed and washed.

[0060] The biggest difference between the above-mentioned comparative examples 1, 2, and 3 and the first embodiment is that the copper source is replaced with copper stearate, copper sulfate, and copper nitrate. However, the polyether polyol in the first comparative example will no longer self-foam. The aerogel in the second comparative example hardens and is no longer hydrophilic, and cannot be effectively evaporated. The aerogel produced in the third comparative example has a poor hydrophilic effect. In the evaporation experiment, it shows 1.07 kg·m -2 ·h -1 , the lower rate is not suitable for commercial production.

[0061] Of course, the above embodiments of the present invention are only examples for illustrating the present invention, and are not intended to limit the specific implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above examples. It is impossible to give detailed examples of all implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for preparing a foamed aerogel elastomer with integrated photothermal and hydrophilic design, characterized in that: The steps include: (1) Add copper acetylacetonate to polyether polyol and stir to obtain a uniform dispersion; the amount ratio of polyether polyol to copper acetylacetonate is 10:0.5-3 in ml:g; (2) Quickly add diphenylmethane diisocyanate to the dispersion and stir rapidly and vigorously with a glass rod. Foam and mature at a constant temperature of 30 ºC for 4 h. (3) After cutting and shaping the sample obtained in step (2), the sample was placed in a 14 wt % (NH4)2S solution for immersion reaction for 12 h. After the reaction was completed, the unreacted raw materials were repeatedly squeezed and washed away, and the foamed aerogel elastomer was obtained after drying.

2. The method according to claim 1, characterized in that: Step (1) The ratio of polyether polyol to copper acetylacetonate in ml:g is 10:

1.

3. The method according to claim 1, characterized in that: In step (2), the volume ratio of diphenylmethane diisocyanate to polyether polyol is 1:

2.

4. Use of the foamed aerogel elastomer obtained by any one of the preparation methods of claims 1 to 3 in photothermal evaporator materials.

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