Application of praseodymium oxide nanoparticles in solar evaporator and solar evaporator

Abstract

The present invention discloses an application of praseodymium oxide nanoparticles in a solar evaporator and a solar evaporator, belonging to the field of interface evaporators. The technical solution includes using praseodymium oxide nanoparticles as light absorbing materials in a solar evaporator to convert solar energy into thermal energy and use it for photothermal evaporation. The present invention is applied to solar evaporators to solve the problems of low solar energy conversion efficiency, low water transport and environmental risks in existing photothermal elements. It has the characteristics of integrating the triple capabilities of photothermal conversion, water transport and thermal insulation, and is efficient, environmentally friendly and low-cost.

Description

Technical Field

[0001] The invention belongs to the field of interface evaporators, and in particular relates to an application of praseodymium oxide nanoparticles in a solar evaporator and a solar evaporator. Background Art

[0002] Solar evaporation, as a green and efficient way to utilize solar energy, can utilize the two most abundant resources on Earth: solar energy and water. It can directly convert low-energy solar energy into high-energy thermal energy and steam energy. Generating steam and clean water from wastewater or seawater is a basic application of solar evaporation technology and one of the most promising green and sustainable solutions to the urgent challenge of global water shortage.

[0003] Traditional water evaporation using solar radiation as a heat source has the disadvantage of low solar energy conversion efficiency due to the large amount of heat loss to water or the external environment. Therefore, an ideal light-to-heat conversion element for building an efficient solar interfacial evaporation system requires some key properties, such as high efficiency as a light absorber, thermal insulation to block heat, and a hydrophilic porous structure that provides a channel for water transport. In order to improve the efficiency of solar-driven water evaporation, a lot of attempts have been made in three aspects: improving the efficiency of light-to-heat conversion, preparing hydrophilic porous self-floating substrates, and reducing heat conduction losses.

[0004] However, for typical photothermal cells, the light absorbing element and the water conducting element are separate, and efforts are usually devoted to optimizing the light absorber, but very limited work has been done on optimizing the water transporter. In addition, the chemicals used in traditional absorbers pose environmental risks. Summary of the invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to overcome the problems of low solar energy conversion efficiency, low water transport and environmental risks in the existing photothermal elements, and propose an application of praseodymium oxide nanoparticles in a solar evaporator and a solar evaporator which has the triple capabilities of photothermal conversion, water transport and thermal insulation, and is efficient, environmentally friendly and low-cost.

[0006] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0007] On one hand, the present invention provides an application of praseodymium oxide nanoparticles in a solar evaporator. The praseodymium oxide nanoparticles are used as light absorbing materials in the solar evaporator to convert solar energy into thermal energy for photothermal evaporation.

[0008] Preferably, the method comprises: uniformly mixing the praseodymium oxide nanoparticles in a dopamine solution to form a mixed solution, immersing a sponge carrier in the mixed solution and fully absorbing the mixed solution, and drying to obtain a sponge modified with praseodymium oxide nanoparticles and polydopamine.

[0009] Preferably, the method comprises: reacting the praseodymium oxide nanoparticles with a H2O2 solution, recovering the praseodymium oxide precipitate by centrifugation, drying to obtain a powder, adding the powder to an alkaline dopamine solution to make the powder concentration be 1-4 g / L, stirring until the powder is evenly dispersed in the alkaline dopamine solution to obtain a mixed solution, fully immersing the sponge carrier in the mixed solution, and repeatedly squeezing the sponge carrier several times to allow the sponge carrier to fully absorb the mixed solution, placing the sponge carrier that has fully absorbed the mixed solution in an air drying oven to dry, and obtaining a sponge modified with praseodymium oxide nanoparticles and polydopamine.

[0010] Preferably, the sponge modified with praseodymium oxide nanoparticles and polydopamine is in the shape of a mushroom, including a rhizome portion and a cap portion; the rhizome portion is a channel for water transfer and diffusion; the top of the cap portion is an evaporation interface; the cap portion remains moist after receiving water from the rhizome portion, and performs photothermal evaporation at the evaporation interface.

[0011] Preferably, the cap part is a rectangular parallelepiped, and the rhizome part is a cube.

[0012] Preferably, the cap part has a length of 4 cm, a width of 4 cm and a height of 1 cm; the rhizome part has a length of 1 cm, a width of 1 cm and a height of 1 cm.

[0013] Preferably, the praseodymium oxide nanoparticles are prepared by the following method: using Pr(NO3)3·6H2O as a praseodymium source, preparing a praseodymium nitrate solution, adding concentrated ammonia water as a precipitant to the praseodymium nitrate solution, heating and stirring to obtain a uniform cyan colloid, centrifuging the obtained cyan colloid to obtain a cyan colloidal precipitate, washing, drying to obtain a cyan powder, and calcining the cyan powder to obtain the praseodymium oxide nanoparticles.

[0014] On the other hand, the present invention provides a solar evaporator, using the praseodymium oxide nanoparticles described in any of the above technical solutions in the solar evaporator. The praseodymium oxide nanoparticles are used as light absorbing materials in the solar evaporator to convert solar energy into thermal energy for photothermal evaporation.

[0015] Preferably, the solar evaporator comprises a sponge carrier, and praseodymium oxide nanoparticles and polydopamine modified on the sponge carrier.

[0016] Preferably, the sponge carrier is in the shape of a mushroom.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides an application of praseodymium oxide nanoparticles in a solar evaporator. The praseodymium oxide nanoparticles are used as light absorbing materials to convert solar energy into thermal energy and use it for photothermal evaporation, which has the characteristics of low cost, environmental protection and high efficiency.

[0019] The present invention provides an application of praseodymium oxide nanoparticles in a solar evaporator, specifically defining a sponge modified with praseodymium oxide nanoparticles and polydopamine in a mushroom shape, including a rhizome part and a cap part, wherein the rhizome part is a channel for water transfer and diffusion, achieving the purpose of high-speed water transport, and the top of the cap part is an evaporation interface, and the cap part remains moist after receiving water from the rhizome part, and performs photothermal evaporation at the evaporation interface, with high light absorption rate and high conversion efficiency, and has the characteristics of integrating the triple capabilities of photothermal conversion, water transportation and thermal insulation, and being high-efficiency, environmentally friendly and low-cost;

[0020] The present invention also provides a solar evaporator, which has the characteristics of high efficiency, environmental protection, low cost and integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a solar evaporator provided in an embodiment of the present invention;

[0022] Figure 2 Another structural schematic diagram of a solar evaporator provided by an embodiment of the present invention;

[0023] Figure 3 A schematic diagram of the use of a solar evaporator provided in an embodiment of the present invention;

[0024] Figure 4 The solar evaporator provided in the embodiments and comparative examples of the present invention has different Pr6O 11 Schematic diagram of evaporation efficiency under concentration;

[0025] Figure 5 A schematic diagram of the evaporation efficiency of the solar evaporator provided in the embodiments and comparative examples of the present invention at different PDA concentrations;

[0026] Figure 6 A schematic diagram of the evaporation efficiency of the solar evaporator provided in the embodiments and comparative examples of the present invention under different sponges and sponge densities;

[0027] Figure 7 A schematic diagram of the evaporation efficiency of the solar evaporator provided in Example 1 of the present invention under different solar intensities;

[0028] In the above figures: 1. Rhizome part; 2. Cap part. DETAILED DESCRIPTION

[0029] The technical scheme in the specific embodiment of the present invention will be described in detail and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only some specific implementation methods of the overall technical scheme of the present invention, rather than all implementation methods. Based on the overall concept of the present invention, all other embodiments obtained by ordinary technicians in this field fall within the scope of protection of the present invention.

[0030] On one hand, the present invention provides an application of praseodymium oxide nanoparticles in a solar evaporator. The praseodymium oxide nanoparticles are used as light absorbing materials in the solar evaporator to convert solar energy into thermal energy and used for photothermal evaporation, and have the characteristics of low cost, environmental protection and high efficiency. In a preferred embodiment, the praseodymium oxide nanoparticles are prepared by the following method: Pr(NO3)3·6H2O is used as a praseodymium source, a praseodymium nitrate solution is prepared, concentrated ammonia water is added to the praseodymium nitrate solution as a precipitant, heating and stirring to obtain a uniform cyan colloid, centrifuging the obtained cyan colloid to obtain a cyan colloidal precipitate, washing, drying to obtain a cyan powder, and calcining the cyan powder to obtain the praseodymium oxide nanoparticles.

[0031] It should be noted that in terms of the selection of light-absorbing layer materials, the existing literature mainly includes precious metal nanoparticles, polymers, nanocarbon materials, etc. They have strong light absorption, but the light-to-heat conversion efficiency is not very high and the cost is high; in terms of improving water-absorbing materials, there are mainly polyurethane foam, inorganic materials, and natural wood, but the evaporation efficiency is still not very high. The application method of the present invention synthesizes praseodymium oxide nanoparticles by direct precipitation method, which is simple and convenient to prepare, and has low cost, and can prepare praseodymium oxide nanoparticles in large quantities. The praseodymium oxide nanoparticles are Pr6O 11 Nanoparticles are used as light-absorbing materials for solar evaporators, where Pr6O 11 Nanomaterials have high absorbance in the range of 200-2500nm and have good photothermal conversion performance.

[0032] In a preferred embodiment, the method comprises: uniformly mixing the praseodymium oxide nanoparticles in a dopamine solution to form a mixed solution, immersing a sponge carrier in the mixed solution and fully absorbing the mixed solution, and drying to obtain a sponge modified with praseodymium oxide nanoparticles and polydopamine. Preferably, the sponge carrier is selected from a melamine sponge carrier or a polyurethane sponge carrier. By the above method, the praseodymium oxide nanoparticles are uniformly loaded on the sponge carrier, and the Pr6O 11Modified on the porous sponge, PDA can also increase the hydrophilicity of the sponge, promote the capillary rise of water to the capillary area, and promote the rapid replenishment of evaporated surface water. Specifically, the sponge has an interconnected porous structure and good mechanical stability, which can provide excellent reusability and a platform for large-scale photothermal evaporation; PDA has excellent adhesion, biocompatibility and self-polymerization properties, and PDA-based materials can be prepared under mild conditions. By using the adhesive effect of PDA, Pr6O 11 In addition, PDA can also increase the hydrophilicity of the sponge, promote the capillary rise of water to the capillary area, and promote the rapid replenishment of evaporated surface water, thus constructing a Pr6O-based 11 / PDA 3D porous sponge evaporator, by adjusting the shape and type of sponge, the modified Pr6O 11 and PDA concentration, achieving high-efficiency solar evaporation.

[0033] In a preferred embodiment, the method comprises: reacting the praseodymium oxide nanoparticles with H2O2 solution, centrifugally recovering the praseodymium oxide precipitate, drying to obtain a powder, adding the powder to an alkaline dopamine solution to make the powder concentration be 1-4 g / L, stirring until the powder is evenly dispersed in the alkaline dopamine solution to obtain a mixed solution, fully immersing the sponge carrier in the mixed solution, and repeatedly squeezing several times to allow the sponge carrier to fully absorb the mixed solution, placing the sponge carrier that has fully absorbed the mixed solution in a blast drying oven to dry, and obtaining a sponge modified with praseodymium oxide nanoparticles and polydopamine. Preferably, the concentration of the alkaline dopamine solution is 1-4 g / L. This embodiment specifically defines the powder concentration, and it is understood that the concentration can also be 2 g / L, 3 g / L, and any point value within the range thereof; this embodiment further defines the concentration of the alkaline dopamine solution, and it is understood that the concentration can also be 2 g / L, 3 g / L, and any point value within the range thereof.

[0034] In a preferred embodiment, if Figure 1 , 2 As shown, the sponge modified with praseodymium oxide nanoparticles and polydopamine is in the shape of a mushroom, including a root portion 1 and a cap portion 2; Figure 3As shown, the root stem 1 is a channel for water transfer and diffusion; the top of the cap part 2 is an evaporation interface; the cap part 2 receives water from the root stem 1 and remains moist, and performs photothermal evaporation at the evaporation interface. The solar evaporator provided by the present invention is inspired by the fly agaric, wherein the root stem of the fly agaric absorbs underground water, the upper thick cap remains moist, and the stem is a channel for its water transfer and diffusion, wherein a large amount of crude fiber, hemicellulose and lignin are contained to form a channel, so that it can absorb a large amount of water. This structure can be used in the solar evaporator to obtain a high-speed water transport channel. In addition, the cap of the fly agaric is thick and uneven, with many white tumor-like spots on it, and the rough surface increases its surface area, which means that the light receiving area is increased in the photothermal evaporator, and the light absorption rate is increased. Therefore, a mushroom-shaped sponge modified by praseodymium oxide / polydopamine is designed as an interface photothermal evaporator, which integrates the triple capabilities of photothermal conversion, water transportation and thermal insulation.

[0035] In a preferred embodiment, the cap part 2 is a cuboid, and the rhizome part 1 is a cube. Further, the cap part 2 has a length of 4 cm, a width of 4 cm, and a height of 1 cm; the rhizome part 1 has a length of 1 cm, a width of 1 cm, and a height of 1 cm. This embodiment further defines the shape and size of the cap part 2 and the rhizome part 1, which is conducive to further improving the evaporation effect of the evaporator. It should be noted that in order to study the influence of the shape and size of the carrier made of melamine sponge on the final photothermal conversion, the present invention designs a three-dimensional mushroom shape of 4*4*1+1*1*1, 4*4*0.5+1*1*1, 2*2*1+1*1*1cm, and a cube shape of 4*4*1, 2*2*1cm for a total of 5 shapes for experiments, and simulates and analyzes the capillary pressure distribution of mushroom-shaped sponges and cubic sponges. Through the evaporation experimental data, it is found that the evaporation effect of the three-dimensional mushroom-shaped evaporator of 4*4*1+1*1*1cm is the most significant.

[0036] Another aspect of the present invention provides a solar evaporator, using the praseodymium oxide nanoparticles listed in any of the above embodiments in the solar evaporator as light absorbing materials to convert solar energy into thermal energy for photothermal evaporation. The praseodymium oxide nanoparticles are Pr6O 11 Nanoparticles are used as light-absorbing materials for solar evaporators, where Pr6O 11 Nanomaterials have high absorbance in the range of 200-2500nm and have good photothermal conversion performance.

[0037] In a preferred embodiment, the solar evaporator includes a sponge carrier, and praseodymium oxide nanoparticles and polydopamine modified on the sponge carrier. The sponge has an interconnected porous structure and good mechanical stability, which can provide excellent reusability and a platform for large-scale photothermal evaporation; PDA has excellent adhesion, biocompatibility and self-polymerization properties, and PDA-based materials can be prepared under mild conditions. 11 In addition, PDA can also increase the hydrophilicity of the sponge, promote the capillary rise of water to the capillary area, and promote the rapid replenishment of evaporated surface water, thus constructing a Pr6O-based 11 / PDA 3D porous sponge evaporator, by adjusting the shape and type of sponge, the modified Pr6O 11 and PDA concentration, achieving high-efficiency solar evaporation.

[0038] In a preferred embodiment, the sponge carrier is in the shape of a mushroom. 11 / PDA's 3D porous sponge solar evaporator has the advantages of high-efficiency solar evaporation, green and efficient environmental protection, low production cost, high universality, good stability, strong portability, etc. In addition, the bionic integrated structure inspired by mushrooms can effectively prevent oxidation and degradation, and has the characteristics of high efficiency and environmental protection, strong light absorption and photothermal conversion capabilities. At the same time, it also has the advantages of simple production, low cost, easy to carry and reusable.

[0039] In order to more clearly and in detail introduce the application of the praseodymium oxide nanoparticles in the solar evaporator and the solar evaporator provided by the embodiments of the present invention, a description will be given below in conjunction with specific embodiments.

[0040] Example 1

[0041] 1. Preparation of praseodymium oxide nanoparticles

[0042] Pr(NO3)3·6H2O was used as the praseodymium source, 50 mL of praseodymium nitrate solution was prepared, concentrated ammonia was added as a precipitant, and the beaker was placed on a temperature-controlled magnetic stirrer (1000r / min, 80°C) and heated for 3 hours. After heating and stirring, the mixture was cooled and allowed to stand for 48 hours to obtain a uniform turquoise colloid. The obtained colloid was centrifuged (10000r / min, 30min) to obtain a turquoise colloidal precipitate, which was washed three times with anhydrous ethanol and deionized water respectively; the precipitate was taken out and placed in a clean beaker, and air was blown at 100°C for 10 hours to obtain a turquoise powder, which was then placed in a crucible and calcined at 500°C in a muffle furnace for 3 hours to obtain praseodymium oxide nanoparticles (Pr6O 11 NP).

[0043] 2. Load

[0044] The prepared praseodymium oxide nanoparticles (Pr6O 11 NP) was reacted with H2O2 solution for 30 min, and the praseodymium oxide precipitate was recovered by centrifugation, dried at 80℃ for 24 h, and the sample was recovered. 11 powder to obtain a mixed solution, in which Pr6O 11 The concentration of praseodymium oxide was 2 g / L (the dopamine solution prepared under acidic conditions was no longer added with praseodymium oxide), and the mixture was stirred for 48 h to make it evenly dispersed in the dopamine solution to synthesize Pr6O 11 and PDA mixed solution. Fully immerse the melamine sponge in the solution and squeeze it repeatedly several times to allow the sponge to fully absorb the solution. Put the sponge that has fully absorbed the mixed solution of praseodymium oxide and polydopamine into a 60°C forced air drying oven for drying. Weigh the mass of the cut clean sponge and the mass of the sponge that has been modified with praseodymium oxide and polydopamine and dried on an electronic balance to obtain a solar evaporator.

[0045] During the loading process, the concentration of alkaline dopamine was 2 g / L, and the Pr6O 11 The concentration is 2g / L; the size of the melamine sponge is 4*4*1+1*1*1cm (that is, the length of the cap part 2 is 4cm, the width is 4cm, and the height is 1cm; the length of the rhizome part 1 is 1cm, the width is 1cm, and the height is 1cm).

[0046] Example 2

[0047] Preparation and loading of praseodymium oxide nanoparticles are the same as in Example 1, except that Pr6O 11 The concentration is 1g / L.

[0048] Example 3

[0049] Preparation and loading of praseodymium oxide nanoparticles are the same as in Example 1, except that Pr6O 11 The concentration is 3g / L.

[0050] Example 4

[0051] Preparation and loading of praseodymium oxide nanoparticles are the same as in Example 1, except that Pr6O 11 The concentration is 4g / L.

[0052] Example 5

[0053] The preparation and loading of praseodymium oxide nanoparticles were the same as in Example 1, except that the concentration of alkaline dopamine was 1 g / L.

[0054] Example 6

[0055] The preparation and loading of praseodymium oxide nanoparticles were the same as in Example 1, except that the concentration of alkaline dopamine was 3 g / L.

[0056] Example 7

[0057] The preparation and loading of praseodymium oxide nanoparticles were the same as in Example 1, except that the concentration of alkaline dopamine was 4 g / L.

[0058] Example 8

[0059] The preparation and loading of praseodymium oxide nanoparticles are the same as in Example 1, except that the sponge is a high-density polyurethane sponge.

[0060] Example 9

[0061] The preparation and loading of praseodymium oxide nanoparticles are the same as in Example 1, except that the sponge is a medium-density polyurethane sponge.

[0062] Example 10

[0063] The preparation and loading of praseodymium oxide nanoparticles are the same as in Example 1, except that the sponge is a low-density polyurethane sponge.

[0064] Comparative Example 1

[0065] Preparation and loading of praseodymium oxide nanoparticles are the same as in Example 1, except that Pr6O 11 The concentration of praseodymium oxide nanoparticles (Pr6O 11 NP).

[0066] Comparative Example 2

[0067] The preparation and loading of praseodymium oxide nanoparticles were the same as in Example 1, except that the concentration of alkaline dopamine was 0 g / L, that is, alkaline dopamine was not used in the loading process.

[0068] Performance Testing

[0069] The evaporation efficiency of the solar evaporators prepared in the above examples 1-10 and comparative examples 1-2 was tested. The test results are as follows: Figure 4-6 shown.

[0070] The evaporation efficiency of the solar evaporator prepared in Example 1 was tested under different solar intensities. The test results are as follows: Figure 7 shown.

Claims

1. An application of praseodymium oxide nanoparticles in a solar evaporator, characterized in that: The praseodymium oxide nanoparticles are used as light absorbing materials in a solar evaporator to convert solar energy into thermal energy and be used for photothermal evaporation, including: The praseodymium oxide nanoparticles are reacted with H2O2 solution, the praseodymium oxide precipitate is recovered by centrifugation, and a powder is obtained by drying. The powder is added to an alkaline dopamine solution to make the powder concentration be 1-4 g / L, and the powder is stirred until it is uniformly dispersed in the alkaline dopamine solution to obtain a mixed solution. A sponge carrier is fully immersed in the mixed solution and squeezed repeatedly several times so that the carrier fully absorbs the mixed solution. The sponge carrier that has fully absorbed the mixed solution is placed in a forced air drying oven and dried to obtain a sponge modified with praseodymium oxide nanoparticles and polydopamine. The sponge modified with praseodymium oxide nanoparticles and polydopamine is in the shape of a mushroom, including a rhizome and a cap part; the rhizome is a channel for water transfer and diffusion; the top of the cap part is an evaporation interface; the cap part remains moist after receiving water from the rhizome, and photothermal evaporation is performed at the evaporation interface.

2. The use of praseodymium oxide nanoparticles in a solar evaporator according to claim 1, characterized in that: The cap part is a rectangular parallelepiped, and the rhizome part is a cube.

3. The use of praseodymium oxide nanoparticles in a solar evaporator according to claim 2, characterized in that: The length of the cap part is 4 cm, the width is 4 cm, and the height is 1 cm; the length of the rhizome part is 1 cm, the width is 1 cm, and the height is 1 cm.

4. The use of praseodymium oxide nanoparticles in a solar evaporator according to claim 1, characterized in that: The praseodymium oxide nanoparticles are prepared by the following method: Pr(NO3)3•6H2O is used as a praseodymium source to prepare a praseodymium nitrate solution, concentrated ammonia water is added into the praseodymium nitrate solution as a precipitant, and heated and stirred to obtain a uniform cyan colloid. The obtained cyan colloid is centrifuged to obtain a cyan colloidal precipitate, which is washed and dried to obtain a cyan powder. The cyan powder is calcined to obtain the praseodymium oxide nanoparticles.

5. A solar evaporator, characterized in that: The praseodymium oxide nanoparticles according to any one of claims 1 to 4 are used in a solar evaporator, wherein the praseodymium oxide nanoparticles are used as light absorbing materials in the solar evaporator to convert solar energy into thermal energy for photothermal evaporation; the solar evaporator comprises a sponge carrier, and praseodymium oxide nanoparticles and polydopamine modified on the sponge carrier.

6. The solar evaporator according to claim 5, characterized in that: The sponge carrier is in the shape of a mushroom.

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