Method for improving performance of photo-thermal evaporation-promoting composite material

Abstract

The invention discloses a method for improving the performance of a photo-thermal evaporation-promoting composite material, relates to the technical field of synthesis of solar seawater desalination materials and preparation of devices, and aims to solve the problems that a traditional photo-thermal material (such as metal nanoparticles and a carbon material) depends on a complex process and is high in cost, and a fiber or foam substrate of the traditional photo-thermal material has imbalance in heat transfer and storage. As a result, the photo-thermal conversion efficiency is low, the waste heat loss is large, the comprehensive cost is higher than that of a traditional technology, organic micromolecule photo-thermal materials are highly concerned due to the adjustable structure and remarkable functionalization potential, but the practical application of the organic micromolecule photo-thermal materials still faces challenges such as insufficient sunlight absorbance, low conversion efficiency and serious substrate heat dissipation. By shearing and optimizing a small molecular structure and a substrate micro-nano layered pore structure for heat preservation, loading high-efficiency photo-thermal molecules with high-porosity sponge fibers, enhancing heat concentration and light reflection by using layered pores, and combining with super-hydrophilic anti-oxidation characteristics, the evaporation efficiency and the material utilization rate are remarkably improved, and low-cost and high-efficiency seawater desalination is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of the synthesis of solar desalination materials and the preparation of devices, and particularly relates to a method for improving the performance of a composite material for photothermal evaporation promotion. Background Art

[0002] Under the background of the global population growth and the accelerating industrialization process, the shortage of fresh water resources has become a core issue threatening the survival and development of mankind. As the most abundant renewable energy source, using solar energy to drive seawater evaporation, collection, and desalination has gradually become a new, environmentally friendly, and economical means. Generally, a seawater desalination evaporator usually consists of two parts: a photothermal conversion material and a supporting substrate. In recent years, widely studied photothermal materials include metal nanoparticles, carbon materials, etc., and the support is mostly a substrate made of various fibers.

[0003] Traditionally, photothermal materials such as metal nanoparticles, carbon materials, and polymer polymers have shown good application potential in the field of photothermal conversion. However, the existing technologies still have the following defects: Photothermal materials need to rely on complex processes to prepare noble metal or carbon-based nanomaterials, resulting in high costs; traditional fiber or foam substrates are difficult to balance heat transfer and preservation; the photothermal conversion efficiency of photothermal materials is low; the heat preservation ability of the substrate material is poor, resulting in a large amount of waste heat, and the comprehensive cost is still higher than that of traditional desalination technologies. These bottlenecks jointly limit the large-scale application of solar desalination, and it is urgent to achieve technological breakthroughs through material innovation and structural design.

[0004] In contrast, organic small molecule photothermal materials, with their flexibility in structural design, wide tunability of properties, and rich functionalization potential, have opened up a new direction for the research of photothermal conversion materials. However, organic small molecule photothermal materials still face engineering application problems such as low absorption of sunlight, low photothermal conversion efficiency, and serious heat dissipation of the substrate material in practical applications. Therefore, a method for improving the performance of a composite material for photothermal evaporation promotion is urgently needed. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method for improving the performance of a composite material for photothermal evaporation promotion, which can effectively solve the problems in the background art.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for improving the performance of a composite material for photothermal evaporation promotion, including the steps of synthesizing an organic small molecule compound and using an evaporator composed of photothermal small molecules. The steps of synthesizing the organic small molecule compound are as follows:

[0008] S1.1: Add raw material compound 1, compound R, a catalyst, and a solvent into a reaction vessel;

[0009] S1.2: Introduce argon into the reaction vessel. After introducing argon, set the temperature around the reaction vessel to a constant 65 °C, and then let the argon reflux in the reaction vessel.

[0010] S1.3: After the argon reflux ends, cool the reaction vessel until the temperature in the reaction vessel gradually drops to room temperature (25 °C).

[0011] S1.4: After the temperature of the reaction vessel drops to room temperature (25 °C), pour the reaction product into 200 mL of methanol and filter. The precipitate obtained after filtration is separated by silica gel column chromatography to obtain a black solid, which is the organic conjugated small molecule material of Compound 3.

[0012] The steps of the evaporator composed of the photothermal small molecule are as follows:

[0013] S2.1: Add three milligrams of the organic small molecule obtained in S1.4 into an organic solvent and stir to dissolve it fully to obtain a solution of compound molecules.

[0014] S2.2: Uniformly drip the solution of compound molecules dissolved with small molecules onto a sponge substrate and dry it naturally in a fume hood.

[0015] S2.3: After the organic solvent volatilizes, an evaporator composed of photothermal small molecules is obtained.

[0016] In the steps of synthesizing the organic small molecule compound, the preparation of the compound can achieve the effects of different shear groups through different reaction conditions. The linking methods between the donor group and the acceptor group after the reaction are divided into two types: one is that the linking method between the donor group and the acceptor group in the compound is in parallel connection, and the other is that the donor group and the acceptor group in the compound are bridged; different catalysts can be selected during the reaction, including pyridine, piperidine, triethylamine, and diethylamine, the solvents are methanol, ethanol, isopropanol, n - hexane, acetone, dichloromethane, and chloroform, the time range for introducing argon is 5 - 50 minutes, and the reflux time is 5 - 50 hours. After experiments, the linking method between the donor group and the acceptor group is selected as bridging.

[0017] Among them, in S2.2, the sponge used is a porous layered sponge.

[0018] Preferably, the mass percentage concentration of the Compound 3 solution is 1% - 30%, and the drying time is 1 - 50 hours.

[0019] Preferably, in step 1.4, the silica gel column chromatography uses silica gel with 200 - 300 mesh, and the eluent is petroleum ether / dichloromethane with a volume ratio of 1:2.

[0020] Preferably, the organic solvent includes methanol, ethanol, isopropanol, n-hexane, acetone, dichloromethane, and chloroform. The stirring temperature is 30-80°C, and the stirring time is 1-50 hours.

[0021] Compared with the prior art, the present invention has the following beneficial effects

[0022] The present invention improves the heat preservation mechanism of the photothermal small molecule structure combined with the micro-nano layered porous structure of the substrate material by means of shearing, synergistically improves the evaporation efficiency of the evaporator, and experiments on the photothermal small molecule structures with different linking methods between the donor group and the acceptor group in the compound to obtain the optimal photothermal small molecule structure, further improving the evaporation efficiency of the evaporator.

[0023] The present invention selects sponge fibers with a larger porosity, synthesizes organic photothermal small molecules through a simple one-step organic synthesis process, dissolves them in a volatile organic solvent, and uniformly drops them on a specific sponge substrate to obtain a photothermal seawater desalination evaporator with excellent light absorption ability and high conversion efficiency.

[0024] In summary, through the mechanism proposed by the present invention, the evaporation efficiency of the evaporator can be further improved, and the economic benefits of the evaporator can be increased. Moreover, the innovation of the synthesis scheme can improve the efficiency of raw materials, and more significant effects can be achieved using the same raw materials. In addition, by introducing a layered pore mechanism on the substrate, the heat generated during the photothermal conversion process can be concentratedly utilized, and the layered pore structure is more conducive to the continuous reflection and absorption of light in the substrate material. Due to the superhydrophilicity of the sponge fibers, the substrate can also have self-suspension and anti-photooxidation properties. Description of the Drawings

[0025] 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 the description of the embodiments or the prior art. Obviously, the drawings in the following description 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.

[0026] Figure 1 It is a schematic diagram of synthesizing photothermal molecules in the present invention and a schematic diagram of specifically preparing a high-efficiency photothermal seawater desalination evaporator;

[0027] Figure 2 It is the photothermal temperature curve and the first water evaporation weight loss curve in the first embodiment of the present invention;

[0028] Figure 3 It is the photothermal temperature curve and the second water evaporation weight loss curve in the second embodiment of the present invention;

[0029] Figure 4This is the third of the photothermal temperature curve and water evaporation weight loss curve in the embodiments of the present invention;

[0030] Figure 5 This is an enlarged view of the molecular formula of compound A of the present invention;

[0031] Figure 6 This is an enlarged view of the molecular formula of compound B of the present invention;

[0032] Figure 7 This is an enlarged view of the molecular formula of compound C of the present invention;

[0033] Figure 8 This is an enlarged view of the molecular formula of compound D of the present invention;

[0034] Figure 9 This is an enlarged view of the molecular formula of compound R of the present invention;

[0035] In the figure: a. The synthesis path of the organic small molecule photothermal material before the improvement of the shearing means; b. The synthesis path of the organic small molecule photothermal material after the improvement of the shearing means; c. The specific process of preparing the evaporator by the drop coating method. Detailed implementation manners

[0036] To make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific implementation manners.

[0037] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0039] Embodiment

[0040] Please refer to Figures 1-4 , the present invention provides a technical solution:

[0041] The present invention discloses a method for improving the performance of a photothermal evaporation composite material, including the steps of synthesizing an organic small molecule compound and using an evaporator composed of photothermal small molecules. The step of synthesizing the organic small molecule compound is as follows:

[0042] S1.1: Add raw material compound 1, compound R, a catalyst, and a solvent into a reaction vessel;

[0043] S1.2: Introduce argon gas into the reaction vessel. After introducing the argon gas, set the temperature around the reaction vessel to a constant 65 °C, and then the argon gas refluxes in the reaction vessel;

[0044] S1.3: After the argon gas reflux ends, cool the reaction vessel until the temperature in the reaction vessel gradually drops to room temperature (25 °C);

[0045] S1.4: After the temperature of the reaction vessel drops to room temperature (25 °C), pour the reaction product into 200 mL of methanol and filter. The precipitate obtained after filtration is separated by silica gel column chromatography to obtain a black solid, which is the organic conjugated small molecule material of compound 3;

[0046] The steps of using the photothermal small molecules to form an evaporator are as follows:

[0047] S2.1: Add three milligrams of the organic small molecule obtained in S1.4 into an organic solvent and stir to fully dissolve it to obtain a solution of compound molecules;

[0048] S2.2: Uniformly drop the solution of compound molecules dissolved with small molecules onto a sponge substrate and naturally dry it in a fume hood;

[0049] S2.3: After the organic solvent volatilizes, an evaporator composed of photothermal small molecules is obtained;

[0050] Among the steps of synthesizing the organic small molecule compound, the preparation of the compound can achieve the effects of different shearing groups through different reaction conditions. There are two ways of linking between the donor group and the acceptor group after the reaction: one is that the linking way between the donor group and the acceptor group in the compound is parallel connection, and the other is that the donor group and the acceptor group in the compound are bridged; different catalysts can be selected during the reaction process, including pyridine, piperidine, triethylamine, diethylamine, the solvents are methanol, ethanol, isopropanol, n-hexane, acetone, dichloromethane, chloroform, the time range of introducing argon gas is 5 - 50 minutes, and the reflux time is 5 - 50 hours. Through experiments, the linking way between the donor group and the acceptor group is selected as bridging;

[0051] Among them, in S2.2, the sponge used is a porous layered sponge.

[0052] In Example 1, the steps for synthesizing an organic small molecule compound are as follows:

[0053] Select A as the raw material compound 1 (without shear process improvement) to synthesize B (a, the synthesis route of the organic small molecule photothermal material before shear means improvement). Select pyridine as the catalyst. The linking manner between the donor group and the acceptor group in the compound is parallel connection. The solvent is chloroform. The argon gas passing time is 20 minutes, and the reflux time is 10 hours.

[0054] The steps for using the evaporator composed of photothermal small molecules: Add 3 mg of the organic small molecule B into an organic solvent. The organic solvent is chloroform. The stirring temperature is 40 °C, and the stirring time is 2 hours. The mass percentage concentration of the compound B solution is 3%. Drop the solution onto the layered porous sponge fiber, and the drying time is 2 hours. Based on this evaporator, the temperature can rise to 61.4 °C in the air under one standard sunlight, the evaporation efficiency is 65.2%, and the water evaporation rate is 1.22 kg m -2 h -1 , and obtain the photothermal temperature curve and the water evaporation weight loss curve according to the experiment (as Figure 2 ).

[0055] In Example 2, the steps for synthesizing an organic small molecule compound are as follows:

[0056] Select C as the raw material compound 1 (with shear process improvement) to synthesize D (b, the synthesis route of the organic small molecule photothermal material after shear means improvement). The catalyst is pyridine. The linking manner between the donor group and the acceptor group in the compound is bridging. The solvent is chloroform. The argon gas passing time is 20 minutes, and the reflux time is 10 hours.

[0057] The steps for using the evaporator composed of photothermal small molecules: Add 3 mg of the organic small molecule D into an organic solvent. The organic solvent is chloroform. The stirring temperature is 40 °C, and the stirring time is 2 hours. Among them, the mass percentage concentration of the compound D solution is 3%. Drop the solution onto the ordinary macroporous sponge fiber, and the drying time is 2 hours. Based on this evaporator, the temperature can rise to 54.4 °C in the air under one standard sunlight, the evaporation efficiency is 79%, and the water evaporation rate is 1.52 kg m - 2 h -1 and obtain the photothermal temperature curve and the water evaporation weight loss curve according to the experiment (as Figure 3 ).

[0058] In Example 3, the steps for synthesizing an organic small molecule compound are as follows:

[0059] Select C as the raw material compound 1 (shearing process improvement), synthesize D catalyst as pyridine, there is a bridge between the donor group and the acceptor group in the compound, the solvent is chloroform, the argon passing time is 20 minutes, and the reflux time is 10 hours.

[0060] Steps of using an evaporator composed of photothermal small molecules: The organic solvent is chloroform, the stirring temperature is 40 °C, and the stirring time is 2 hours. Among them, the mass percentage concentration of compound D solution is 3%. The solution is drop-coated on the layered porous sponge fiber, and the drying time is 2 hours. Based on this evaporator, the temperature can rise to 64.1% in the air under a standard sunlight, the evaporation efficiency is 97.0%, and the water evaporation rate is 1.75 kg m -2 h -1 And obtain the photothermal temperature curve and water evaporation weight loss curve according to the experiment (such as Figure 4 ).

[0061] In this Example 4, by combining the experimental results in Examples 1 and 3 and comparing them, the means of improving the photothermal performance by changing the donor-acceptor linkage mode in the transformed organic small molecules is confirmed from the photothermal temperature curve, water evaporation weight loss curve and experimental results. The organic small molecules with a bridging structure can significantly improve the utilization efficiency of the photothermal energy of the evaporator, further improve the evaporation efficiency of the evaporator, and improve the economic benefits of the evaporator.

[0062] In this Example 5, by combining the experimental results in Examples 2 and 3 and comparing them, the layered porous sponge fiber has a better heat preservation strategy compared with the ordinary macroporous sponge fiber. By introducing the layered pore mechanism, the concentrated utilization of the heat generated in the photothermal conversion process can be achieved, and the layered pore structure is more conducive to the continuous reflection and absorption of light in the substrate material. Due to the superhydrophilicity of the sponge fiber, the substrate can also have self-suspension and anti-photooxidation properties, and its cost is lower compared with traditional photothermal materials such as metal nanoparticles, carbon materials and polymer materials.

[0063] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for improving the performance of a photothermal evaporation composite material, comprising the steps of synthesizing an organic small molecule compound and using an evaporator composed of photothermal small molecules, characterized in that: Steps for synthesizing the synthetic organic small molecule compound: S1.1: Add the raw material compound 1, compound R, catalyst, and solvent into a reaction vessel; S1.2: Introduce argon into the reaction vessel. After introducing argon, set the temperature around the reaction vessel to a constant temperature of 65 °C, and then let the argon reflux in the reaction vessel; S1.3: After the argon reflux ends, cool the reaction vessel until the temperature in the reaction vessel gradually drops to room temperature (25 °C); S1.4: After the temperature of the reaction vessel drops to room temperature (25 °C), pour the reaction product into 200 mL of methanol and filter. The precipitate obtained after filtration is separated by chromatography on a silica gel column to obtain a black solid, which is the compound 3 organic conjugated small molecule material; The steps for the evaporator composed of the photothermal small molecule are as follows: S2.1: Add three milligrams of the organic small molecule obtained in S1.4 into an organic solvent and stir to dissolve it fully to obtain a solution of the compound molecules; S2.2: Uniformly drop the solution of the compound molecules dissolved with the small molecules onto a sponge substrate and let it dry naturally in a fume hood; S2.3: After the organic solvent volatilizes, an evaporator composed of the photothermal small molecule is obtained; Among the steps for synthesizing the synthetic organic small molecule compound, the preparation of the compound can achieve the effects of different shearing groups through different reaction conditions. There are two ways of linking between the donor group and the acceptor group after the reaction: one is that the linking method between the donor group and the acceptor group in the compound is parallel connection, and the other is that the donor group and the acceptor group in the compound are bridged; Different catalysts can be selected during the reaction, including pyridine, piperidine, triethylamine, and diethylamine. The solvents are methanol, ethanol, isopropanol, n-hexane, acetone, dichloromethane, and chloroform. The time range for introducing argon is 5 - 50 minutes, and the reflux time is 5 - 50 hours. Through experiments, the linking method between the donor group and the acceptor group is selected as bridging; Among them, in S2.2, the sponge used is a porous layered sponge.

2. A method for improving the performance of a photothermal evaporation composite material according to claim 1, characterized in that: The mass percentage concentration of the compound 3 solution is 1% - 30%, and the drying time is 1 - 50 hours.

3. A method for improving the performance of a photothermal enhanced evaporation composite material according to claim 1, characterized in that: In step 1.4, the silica gel column chromatography uses silica gel with a mesh size of 200 - 300, and the eluent is petroleum ether / dichloromethane with a volume ratio of 1:

2.

4. A method for improving the performance of a photothermal enhanced evaporation composite material according to claim 1, characterized in that: The organic solvents include methanol, ethanol, isopropanol, n-hexane, acetone, dichloromethane, and chloroform. The stirring temperature is 30 - 80 °C, and the stirring time is 1 - 50 hours.

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