A TiN / polyimide aerogel-based solar-driven interface evaporator and its preparation method and application

Abstract

The present invention relates to the field of solar-driven interfacial photothermal evaporation technology, and more particularly to a solar-driven interfacial evaporator based on TiN / polyimide aerogel, its preparation method, and application. The TiN / polyimide aerogel comprises a polyimide aerogel matrix with vertical channels connecting upper and lower surfaces, loaded with TiN nanoparticles. The aerogel is prepared by polycondensation, dehydration, and cyclization of the polyimide aerogel 4,4'-diaminodiphenyl ether and 4,4'-oxydiphthalic anhydride. The TiN / polyimide aerogel provided by the present invention, when used as a solar-driven interfacial evaporator, can not only improve the water transfer performance of a three-dimensional photothermal evaporator, but also increase the photothermal evaporation rate during seawater desalination.

Description

Technical Field

[0001] The present invention relates to the technical field of solar-driven interface photothermal evaporation, and in particular to a TiN / polyimide aerogel-based solar-driven interface evaporator and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Solar-driven interfacial photothermal evaporation technology uses heat generated by photothermal materials absorbing solar energy to convert liquid water into steam. Compared to existing desalination and wastewater treatment technologies, this method does not require additional energy consumption or rely on large-scale infrastructure, and therefore has huge application potential.

[0004] The core of solar-driven interfacial photothermal evaporation technology lies in the design of photothermal evaporation materials. Currently, photothermal evaporation materials mainly include two-dimensional photothermal evaporation films and three-dimensional photothermal evaporators. However, the widespread application of two-dimensional photothermal evaporation films is limited by their poor anti-fouling properties and the potential for aging and degradation of the film material during long-term exposure to sunlight and water vapor during use, thereby shortening its service life. Furthermore, some three-dimensional evaporators suffer from poor water transport performance or easily clogged pore structures due to salt accumulation. The reduced photoevaporation rate caused by the treatment of actual seawater is also a major challenge hindering its large-scale application. Summary of the Invention

[0005] In order to overcome the above problems, the present invention provides a TiN / polyimide aerogel-based solar-driven interface evaporator and its preparation method and application.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a TiN / polyimide aerogel, which uses a polyimide aerogel having a vertically penetrating pore structure as a matrix and is loaded with TiN nanoparticles;

[0008] The polyimide aerogel is prepared by polycondensation and dehydration cyclization of 4,4'-diaminodiphenyl ether and 4,4'-oxydiphthalic anhydride.

[0009] A second aspect of the present invention provides a method for preparing the TiN / polyimide aerogel described in the first aspect, comprising the following steps:

[0010] (1) dissolving 4,4'-diaminodiphenyl ether and 4,4'-oxydiphthalic anhydride in an organic solvent, reacting to obtain a polyamic acid solution; adding acetic anhydride and triethylamine, reacting to obtain a polyimide oligomer; and adding a crosslinking agent to the polyimide oligomer to obtain a polyimide precursor;

[0011] (2) adding TiN nanoparticles to the polyimide precursor, mixing well, transferring to a mold, performing unidirectional freezing, and then freeze-drying until completely dry;

[0012] (3) The completely dried sample was thermally annealed to obtain TiN / polyimide aerogel.

[0013] The third aspect of the present invention provides the use of the TiN / polyimide aerogel described in the first aspect and / or the TiN / polyimide aerogel prepared by the preparation method described in the second aspect as a solar-driven interface evaporator.

[0014] A fourth aspect of the present invention provides a solar-driven interface evaporator comprising the TiN / polyimide aerogel described in the first aspect and / or the TiN / polyimide aerogel prepared by the preparation method described in the second aspect.

[0015] A fifth aspect of the present invention provides the application of the solar-driven interface evaporator described in the fourth aspect in seawater desalination and sewage treatment.

[0016] The beneficial effects of the present invention are:

[0017] (1) The TiN / polyimide aerogel provided by the present invention is used as a solar-driven interface evaporator, which can not only improve the water transport performance of the three-dimensional photothermal evaporator, but also improve the photothermal evaporation rate in the seawater desalination process. Through the one-way freezing technology, the polyimide aerogel has vertical channels connected up and down, which facilitates the radial transportation of water and improves the water transport performance of the three-dimensional photothermal evaporator. TiN nanoparticles with surface plasmon resonance (LSPR) effect are used as photothermal conversion materials. When sunlight irradiates the TiN surface, free electrons are excited and resonant oscillations are generated to enhance the local electric field on the TiN surface, thereby quickly inducing a local heating effect. At the same time, due to the Hofmeister effect, Cl in seawater - It will induce the salting process of polyimide polymer chain, in which Cl -By affecting the structure and arrangement of water molecules, the solvation capacity of water molecules and the structure of the hydration shell are changed, and the hydrogen bonding between water molecules is weakened, thereby affecting the intermolecular force formed by π-π stacking of two adjacent chains in the polyimide network, thereby enhancing the hydration of the polyimide polymer chain and allowing more carbonyl groups on the amide groups to contact water molecules. At the polyimide-water interface, the hydrogen bonding effect is further enhanced, increasing the intermediate water content and reducing the evaporation enthalpy of water, thereby greatly improving the photothermal evaporation rate.

[0018] (2) Compared with precious metals such as Au and Ag that have surface plasmon resonance effects, TiN nanoparticles are cheaper and therefore have greater advantages in large-scale production and application.

[0019] (3) Polyimide aerogel has excellent thermal and chemical stability, and can maintain structural stability under high temperature and harsh environments, making it suitable for long-term stable photothermal evaporation processes. In addition, polyimide aerogel has low density and high mechanical strength, making the photothermal evaporator lightweight and easy to transport and install.

[0020] (4) Hofmeister effect leads to Cl - The induced saltation process of the polyimide polymer chain makes the photothermal evaporation rate of TiN / polyimide aerogel in seawater greater than that in pure water, thus making TiN / polyimide aerogel have broad application prospects in large-scale seawater desalination processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] Figure 1 Figures a, b, and c are scanning electron microscope images of the TiN / polyimide aerogel (0.4-TiN / PI) obtained in Example 4;

[0023] Figure 2 This is a density verification effect diagram of the TiN / polyimide aerogel (0.4-TiN / PI) obtained in Example 4;

[0024] Figure 3 This is a thermal conductivity effect diagram of the TiN / polyimide aerogel (0.4-TiN / PI) obtained in Example 4;

[0025] Figure 4 When the samples obtained in Examples 2 to 6 and Comparative Example 1 in Experimental Example 1 float on the water surface, the light intensity (1 kW m -2) Comparison of water weight loss curve (a) and evaporation rate (b);

[0026] Figure 5 Comparison of evaporation rates of 0.4-TiN / PI at different salinities in Experiment 2, a is the weight loss curve, b is the evaporation rate;

[0027] Figure 6 A diagram of a continuous seawater desalination or sewage treatment device in Experimental Example 3;

[0028] Figure 7 This is a rendering of the effect of seawater desalination using a continuous seawater desalination or sewage treatment device;

[0029] Figure 8 For wastewater treatment using continuous desalination or wastewater treatment plants, the levels of various pollutants in the water before evaporation and in the condensate after evaporation are compared. DETAILED DESCRIPTION

[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] A first typical embodiment of the present invention provides a TiN / polyimide aerogel, which uses a polyimide aerogel having a vertically penetrating pore structure as a matrix and is loaded with TiN nanoparticles;

[0033] The polyimide aerogel is prepared by polycondensation and dehydration cyclization of 4,4'-diaminodiphenyl ether and 4,4'-oxydiphthalic anhydride.

[0034] In one or more embodiments, the mass fraction of TiN nanoparticles in the TiN / polyimide aerogel is 20% to 60%, preferably 40%.

[0035] In one or more embodiments, the particle size of the TiN nanoparticles is 15 to 25 nm, preferably 20 nm.

[0036] In one or more embodiments, the pore size of the polyimide aerogel pore structure is 50 to 200 μm.

[0037] A second typical embodiment of the present invention provides a method for preparing the TiN / polyimide aerogel according to the first aspect, comprising the following steps:

[0038] (1) dissolving 4,4'-diaminodiphenyl ether and 4,4'-oxydiphthalic anhydride in an organic solvent, reacting to obtain a polyamic acid solution; adding acetic anhydride and triethylamine, reacting to obtain a polyimide oligomer; and adding a crosslinking agent to the polyimide oligomer to obtain a polyimide precursor;

[0039] (2) adding TiN nanoparticles to the polyimide precursor, mixing well, transferring to a mold, performing unidirectional freezing, and then freeze-drying until completely dry;

[0040] (3) The completely dried sample was thermally annealed to obtain TiN / polyimide aerogel.

[0041] In one or more embodiments, in step (1), the organic solvent includes dimethyl sulfoxide.

[0042] In one or more embodiments, in step (1), the mass ratio of 4,4'-diaminodiphenyl ether to 4,4'-oxydiphthalic anhydride is (0.6-0.9):(1-1.5), preferably 0.75:1.28.

[0043] In one or more embodiments, in step (1), 4,4'-diaminodiphenyl ether and 4,4'-oxydiphthalic anhydride are dissolved in an organic solvent, and stirred at room temperature to obtain a polyamic acid solution. The stirring reaction time is 10 to 15 hours, preferably 12 hours.

[0044] In one or more embodiments, in step (1), the cross-linking agent includes 1,3,5-tris(4-aminophenoxy)benzene.

[0045] Preferably, after adding the cross-linking agent 1,3,5-tris(4-aminophenoxy)benzene, the cross-linking time is 1 to 2 hours, preferably 1.5 hours.

[0046] In one or more embodiments, in step (3), the thermal annealing temperature is 230-260° C., preferably 250° C.; and the thermal annealing time is 2-4 hours, preferably 3 hours.

[0047] A third typical embodiment of the present invention provides the use of the TiN / polyimide aerogel described in the first aspect and / or the TiN / polyimide aerogel prepared by the preparation method described in the second aspect as a solar-driven interface evaporator.

[0048] A fourth typical embodiment of the present invention provides a solar-driven interface evaporator, comprising the TiN / polyimide aerogel described in the first aspect and / or the TiN / polyimide aerogel prepared by the preparation method described in the second aspect.

[0049] A fifth typical embodiment of the present invention provides the application of the solar-driven interface evaporator described in the fourth aspect in seawater desalination and sewage treatment.

[0050] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0051] Example 1

[0052] 30.5 mL of dimethyl sulfoxide (DMSO) was added to a 100 mL three-necked flask equipped with a mechanical stirring paddle at a stirring speed of 500 r / min and nitrogen was used as a protective gas. Subsequently, 0.75 g of 4,4'-diaminodiphenyl ether was added to the flask and completely dissolved. Then, 1.28 g of 4,4'-oxydiphthalic anhydride was slowly added to the solution. After stirring at room temperature for 12 hours, 75 g of L -1 Then, 0.7 mL of acetic anhydride and 11.15 mL of triethylamine were added to the dispersion and stirred for 1 hour to obtain a polyimide oligomer. 30 mL of the polyimide oligomer was diluted to 180 mL with DMSO to obtain 12.5 g of the polyimide oligomer. -1 A polyimide oligomer / DMSO dispersion was prepared, 0.1 g of 1,3,5-tris(4-aminophenoxy)benzene was added to the dispersion, and cross-linked for 1.5 h to obtain a polyimide precursor / DMSO dispersion.

[0053] Example 2

[0054] 0.125 g of TiN nanoparticles were added to 30 mL of the polyimide precursor / DMSO dispersion prepared in Example 1, and the mixture was magnetically stirred for 10 min and ultrasonicated at low temperature for 30 min to obtain a uniform TiN / polyimide precursor / DMSO dispersion.

[0055] The TiN / polyimide precursor / DMSO dispersion was poured into a mold and unidirectionally frozen in liquid nitrogen; the mold was then transferred to a -80°C freezer and continued to freeze for 12 hours, followed by freeze-drying for 72 hours. Finally, the TiN / polyimide aerogel was thermally annealed at 250°C in a nitrogen atmosphere for 3 hours to obtain a TiN / polyimide aerogel named 0.2-TiN / PI.

[0056] Example 3

[0057] 0.188 g of TiN nanoparticles were added to 30 mL of the polyimide precursor / DMSO dispersion prepared in Example 1, and the mixture was magnetically stirred for 10 min and ultrasonicated at low temperature for 30 min to obtain a uniform TiN / polyimide precursor / DMSO dispersion.

[0058] The TiN / polyimide precursor / DMSO dispersion was poured into a mold and unidirectionally frozen in liquid nitrogen; the mold was then transferred to a -80°C freezer and continued to freeze for 12 hours, followed by freeze drying for 72 hours. Finally, the TiN / polyimide aerogel was thermally annealed at 250°C in a nitrogen atmosphere for 3 hours, and named 0.3-TiN / PI.

[0059] Example 4

[0060] 0.250 g of TiN nanoparticles were added to 30 mL of the polyimide precursor / DMSO dispersion prepared in Example 1, and the mixture was magnetically stirred for 10 min and ultrasonicated at low temperature for 30 min to obtain a uniform TiN / polyimide precursor / DMSO dispersion.

[0061] The TiN / polyimide precursor / DMSO dispersion was poured into a mold and unidirectionally frozen in liquid nitrogen; the mold was then transferred to a -80°C freezer and continued to freeze for 12 hours, followed by freeze drying for 72 hours. Finally, the TiN / polyimide aerogel was thermally annealed at 250°C in a nitrogen atmosphere for 3 hours, and named 0.4-TiN / PI.

[0062] Example 5

[0063] 0.313 g of TiN nanoparticles were added to 30 mL of the polyimide precursor / DMSO dispersion prepared in Example 1, and the mixture was magnetically stirred for 10 min and ultrasonicated at low temperature for 30 min to obtain a uniform TiN / polyimide precursor / DMSO dispersion.

[0064] The TiN / polyimide precursor / DMSO dispersion was poured into a mold and unidirectionally frozen in liquid nitrogen; the mold was then transferred to a -80°C freezer and continued to freeze for 12 hours, followed by freeze-drying for 72 hours. Finally, the TiN / polyimide aerogel was thermally annealed at 250°C in a nitrogen atmosphere for 3 hours to obtain a TiN / polyimide aerogel named 0.5-TiN / PI.

[0065] Example 6

[0066] 0.375 g of TiN nanoparticles were added to 30 mL of the polyimide precursor / DMSO dispersion prepared in Example 1, and the mixture was magnetically stirred for 10 min and ultrasonicated at low temperature for 30 min to obtain a uniform TiN / polyimide precursor / DMSO dispersion.

[0067] The TiN / polyimide precursor / DMSO dispersion was poured into a mold and unidirectionally frozen in liquid nitrogen; the mold was then transferred to a -80°C freezer for further freezing for 12 hours, followed by freeze-drying for 72 hours. Finally, the TiN / polyimide aerogel was thermally annealed at 250°C in a nitrogen atmosphere for 3 hours, and named 0.6-TiN / PI.

[0068] Comparative Example 1

[0069] 30 mL of the polyimide precursor / DMSO dispersion prepared in Example 1 was poured into a mold and unidirectionally frozen in liquid nitrogen. The mold was then transferred to a -80°C freezer and continued to be frozen for 12 h, followed by freeze-drying for 72 h. Finally, the polyimide aerogel was thermally annealed at 250°C in a nitrogen atmosphere for 3 h to obtain the polyimide aerogel, named PI.

[0070] Figure 1 The scanning electron microscope image of the TiN / polyimide aerogel (0.4-TiN / PI) obtained in Example 4 is shown in FIG. Figure 1 It can be seen that TiN / polyimide aerogel has high porosity ( Figure 1 a); and having a vertically penetrating pore structure ( Figure 1 b), this is because the unidirectional freezing makes the solvent crystal grow from bottom to top, forming directional channels, high porosity and vertical channels connected up and down facilitate the smooth flow of water, thus improving the water transport performance; TiN is evenly loaded on the surface of polyimide aerogel ( Figure 1 c), thereby giving the material good photothermal conversion ability. At the same time, it can be seen from the scanning electron microscope that the pore size of the polyimide aerogel pore structure is 50 to 200 μm.

[0071] Figure 2 The density verification effect diagram of the TiN / polyimide aerogel (0.4-TiN / PI) obtained in Example 4 is shown in FIG. Figure 2 It can be seen from the graph that the density of TiN / polyimide aerogel is low.

[0072] The thermal conductivity of the TiN / polyimide aerogel (0.4-TiN / PI) obtained in Example 4 is 3.31 W m -1 K -1 , the thermal insulation effect is as shown in the figure Figure 3 As shown, it can be seen that TiN / polyimide aerogel has good thermal insulation effect.

[0073] Experimental Example 1

[0074] The samples obtained in Examples 2 to 6 and Comparative Example 1 were cut into cubes with a length of 2 × 2 cm and a thickness of 1.2 cm. The light intensity was set to 1 kW m -2, the interfacial photothermal evaporation experiment was carried out in pure water. Working continuously for 3 hours at 25℃, the mass change of water was recorded and the evaporation rate was calculated. The results are as follows Figure 4 shown.

[0075] Due to the vertically penetrating pore structure inside the polyimide aerogel, the water transport performance is improved under the action of capillary force, which increases the water evaporation rate from 0.52 to 0.96 kg m -2 h -1 As the mass fraction of TiN increases, the evaporation rate of TiN / PI increases first and then stabilizes. This is because the LSPR effect of TiN significantly improves the material's heat generation performance, further increasing the evaporation rate. Subsequently, due to the filling effect, the material's heat generation reaches saturation when the mass fraction of TiN is 0.4. Therefore, 0.4-TiN / PI is determined to be the optimal composite ratio.

[0076] Experimental Example 2

[0077] Comparison of 0.4-TiN / PI evaporation rates under different salinities:

[0078] Set the light intensity to 1kW m -2 , 0.4-TiN / PI was placed in NaCl solutions with salt contents of 3.5, 7, 15, and 25 wt.%, and interfacial photothermal evaporation experiments were performed. The experiment was carried out continuously at 25°C for 3 hours, and the mass change of water was recorded and the evaporation rate was calculated. The results are shown in Figure 2. Figure 5 shown.

[0079] from Figure 5 It can be seen that the Hofmeister effect leads to Cl - The salination process of the polyimide polymer chains was induced, which resulted in a higher photothermal evaporation rate of 0.4-TiN / PI aerogel in salt water than in pure water. The maximum evaporation rate was 4.22 kg m at a concentration of 7 wt.% NaCl. -2 h -1 It is noteworthy that when the NaCl concentration is greater than 7 wt.%, the evaporation rate of 0.4-TiN / PI decreases due to the accumulation of salt in the pores, but it is still greater than that in pure water. The unique salt tolerance of 0.4-TiN / PI makes it a reliable choice for interfacial photothermal evaporation for seawater desalination.

[0080] Experimental Example 3

[0081] This experimental example provides a continuous seawater desalination or sewage treatment device, such as Figure 6As shown, a continuous seawater desalination or sewage treatment device includes a circular base plate with an annular protrusion provided on the base plate. The base plate and the annular protrusion are an integral structure and are both made of polystyrene foam. A hole is provided in the middle of the base plate, in which the TiN / polyimide aerogel prepared in Example 4 is placed. An inverted plastic conical funnel is connected around the hole, and a plurality of holes are provided on the side wall of the plastic conical funnel to facilitate the entry and exit of water vapor. An inverted hemispherical plastic cover is connected to the upper surface of the annular protrusion. A water channel is provided at the bottom of the annular protrusion. One end of the plastic water pipe is connected to the space of the hemispherical plastic cover through the water channel, and the other end of the plastic water pipe is connected to a collection device. In order to prevent the plastic water pipe from being immersed in seawater or sewage, the outer wall of the plastic water pipe is wrapped with polystyrene foam. A layer of filter cotton is set at the bottom of the base plate to prevent the falling of TiN / polyimide aerogel and the entry of marine floating plants such as algae; in order to improve the stability of the overall device, the connection between the hemispherical plastic cover and the annular protrusion is sealed with glue; the connection between the plastic water pipe and the collection device is also sealed.

[0082] The above device is used to desalinate seawater. The contents of various ions before and after desalination are as follows: Figure 7 As shown, from Figure 7 It can be seen in the figure. + , Ca 2+ , K + and Mg 2+ The concentrations of the four ions ranged from 9783.6, 5867.2, 5264.1 and 1526.2 mg L -1 decreased to 0.98, 0.57, 0.62, and 0.84 mg L -1 The purification efficiency is greater than 99.9%, and the content of each element in the condensed water meets the WHO and EPA drinking water standards.

[0083] The above device was used to treat sewage, and the content of pollutants in the water before evaporation and the condensed water after evaporation were compared. The results are as follows: Figure 8 As-GW is the actual arsenic-containing groundwater (samples were taken from Shanyin County, Shanxi Province), with a total arsenic content of 320 μg L -1 Sb-IW is antimony-containing industrial wastewater (sample taken from Lengshuijiang City, Hunan Province), with a total antimony content of 14.8 mg L -1 MB-SW and PFOA were respectively laboratory simulated wastewater containing methylene blue and perfluorooctanoic acid, with the contents of methylene blue and perfluorooctanoic acid both at 10 mg / L. -1 No target pollutants were detected in the water collected after the four types of wastewater purification, indicating that TiN / polyimide aerogel has excellent purification ability for wastewater.

[0084] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A TiN / polyimide aerogel, characterized in that: It uses a polyimide aerogel with a vertically penetrating pore structure as a matrix and is loaded with TiN nanoparticles. The polyimide aerogel is prepared by polycondensation and dehydration cyclization of 4,4'-diaminodiphenyl ether and 4,4'-oxydiphthalic anhydride.

2. The TiN / polyimide aerogel according to claim 1, wherein The mass fraction of TiN nanoparticles in TiN / polyimide aerogel is 20%~60%.

3. The TiN / polyimide aerogel according to claim 2, wherein: The mass fraction of TiN nanoparticles in TiN / polyimide aerogel is 40%.

4. The TiN / polyimide aerogel according to claim 1, wherein The particle size of the TiN nanoparticles is 15-25 nm.

5. The TiN / polyimide aerogel according to claim 4, wherein: The particle size of the TiN nanoparticles is 20 nm.

6. The TiN / polyimide aerogel according to claim 1, wherein The pore size of the polyimide aerogel pore structure is 50~200 μm.

7. The method for preparing the TiN / polyimide aerogel according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) dissolving 4,4'-diaminodiphenyl ether and 4,4'-oxydiphthalic anhydride in an organic solvent to react to obtain a polyamic acid solution; adding acetic anhydride and triethylamine to react to obtain a polyimide oligomer; and adding a crosslinking agent to the polyimide oligomer to obtain a polyimide precursor; (2) Add TiN nanoparticles to the polyimide precursor, mix well, transfer to a mold, perform unidirectional freezing, and then freeze-dry until completely dry; (3) The completely dried sample was thermally annealed to obtain TiN / polyimide aerogel.

8. The preparation method according to claim 7, wherein In step (1), the organic solvent includes dimethyl sulfoxide.

9. The preparation method according to claim 7, wherein In step (1), the mass ratio of 4,4'-diaminodiphenyl ether to 4,4'-oxydiphthalic anhydride is (0.6-0.9): (1-1.5).

10. The preparation method according to claim 9, wherein The mass ratio of 4,4'-diaminodiphenyl ether to 4,4'-oxydiphthalic anhydride is preferably 0.75:1.

28.

11. The preparation method according to claim 7, wherein In step (1), 4,4'-diaminodiphenyl ether and 4,4'-oxydiphthalic anhydride are dissolved in an organic solvent, and stirred at room temperature to react to obtain a polyamic acid solution. The stirring reaction time is 10 to 15 hours.

12. The preparation method according to claim 11, characterized in that The stirring reaction time was 12 h.

13. The preparation method according to claim 7, wherein In step (1), the cross-linking agent includes 1,3,5-tris(4-aminophenoxy)benzene.

14. The preparation method according to claim 13, wherein After adding the cross-linking agent 1,3,5-tris(4-aminophenoxy)benzene, the cross-linking time is 1~2 h.

15. The preparation method according to claim 14, wherein After the cross-linking agent 1,3,5-tris(4-aminophenoxy)benzene was added, the cross-linking time was 1.5 h.

16. The preparation method according to claim 7, wherein In step (3), the thermal annealing temperature is 230-260°C; the thermal annealing time is 2-4 h.

17. The preparation method according to claim 16, wherein The thermal annealing temperature is 250°C and the thermal annealing time is 3 h.

18. Use of the TiN / polyimide aerogel according to any one of claims 1 to 6 and / or the TiN / polyimide aerogel prepared by the preparation method according to any one of claims 7 to 17 as a solar-driven interfacial evaporator.

19. A solar-driven interface evaporator, characterized in that: The invention comprises the TiN / polyimide aerogel according to any one of claims 1 to 6 and / or the TiN / polyimide aerogel prepared by the preparation method according to any one of claims 7 to 17.

20. Use of the solar-driven interface evaporator according to claim 19 in seawater desalination and sewage treatment.

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