Evaporation desalination method based on photoacoustic synergistic effect

Abstract

The invention provides a photo-acoustic synergistic effect-based evaporative desalination method, which comprises the following steps: preparing an interface evaporator, putting the interface evaporator into a salt-containing solution, and performing ultrasonic treatment while illuminating. By means of the mode, a good desalting effect can be achieved, the problem that interface evaporators of hydrogel, aerogel, fabric and the like are blocked by salt in the seawater evaporation process is effectively solved, and the service life of the interface evaporators is prolonged. The Janus composite aerogel with a tenon-and-mortise structure is prepared by improving the interface evaporator, the influence of salt blockage can be reduced by utilizing the difference of upper and lower wettability of the Janus composite aerogel, the Janus composite aerogel can completely and independently float on the water surface, the contact with water is converted into point contact from three-dimensional contact, and the evaporation efficiency is effectively improved; the composite aerogel cannot be soaked in a salt-containing solution, so that the influence of salt blockage can be further reduced to a certain extent, meanwhile, the durability of the aerogel is effectively improved, and the service life of the aerogel is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of interface evaporator desalination, in particular to an evaporation desalination method based on photoacoustic synergy. Background Art

[0002] Humans have been using desalination technology to obtain pure water for thousands of years. With the growth of the world's population and economic prosperity, the scarcity of freshwater resources has become increasingly prominent. Removing salt from seawater can generate more freshwater resources to meet people's daily water needs, and research on desalination has garnered widespread attention.

[0003] In addition to traditional desalination methods, solar interfacial evaporation technology has gained significant attention and maturity both domestically and internationally due to its zero-pollution, zero-energy consumption approach. Solar evaporators, often made from aerogels, hydrogels, and fabrics, boast high evaporation efficiencies, and the quality of desalinated seawater meets national drinking water standards. However, salt blockage is a common problem in the desalination process, significantly impacting both the efficiency and lifespan of the evaporator.

[0004] While Janus aerogels can mitigate the effects of salt clogging by exploiting the difference in wettability between the upper and lower portions, this approach still doesn't effectively eliminate the problem. Furthermore, these aerogels often have a hydrophilic layer placed at the bottom, submerging it in water. This not only affects evaporation efficiency, but also exposes the submerged portion to salt clogging, shortening its lifespan. Effectively preventing salt clogging is a current research priority.

[0005] In view of this, it is necessary to design an improved evaporation desalination method to solve the above problems. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, the purpose of the present invention is to provide an evaporation desalination method based on photoacoustic synergy, which effectively desalinates by performing ultrasonic treatment during photoevaporation, prolongs the service life of the interface evaporator, and improves the evaporation efficiency.

[0007] To achieve the above object, the present invention provides an evaporative desalination method based on photoacoustic synergy, comprising the following steps:

[0008] S1. Prepare an interface evaporator;

[0009] S2. placing the interface evaporator in a saline solution and performing ultrasonic treatment while irradiating with light.

[0010] As a further improvement of the present invention, in step S2, the power of the ultrasonic treatment is 80 to 120 W, and the treatment method is: work for 3 to 7 minutes and rest for 3 to 7 minutes.

[0011] As a further improvement of the present invention, in step S1, the interface evaporator includes one of aerogel, hydrogel, and fabric.

[0012] As a further improvement of the present invention, in step S1, the interface evaporator is a Janus composite aerogel with a mortise and tenon structure; the Janus composite aerogel with a mortise and tenon structure includes, from top to bottom, an upper aerogel with hydrophilicity and a lower aerogel with hydrophobicity; the interior of the lower aerogel contains a through hole that penetrates the upper and lower surfaces of the lower aerogel, and the bottom of the upper aerogel contains a columnar protrusion that matches the through hole, and the columnar protrusion forms a mortise and tenon structure with the through hole.

[0013] As a further improvement of the present invention, the preparation method of the Janus composite aerogel having a mortise and tenon structure comprises the following steps:

[0014] S11, fully mixing the nanofiber suspension with the cross-linking agent to obtain a first mixed solution; placing the first mixed solution in a mold, freeze-drying it to form an aerogel, and then performing a hydrophobic modification treatment to obtain a lower layer aerogel; the lower layer aerogel comprises through holes penetrating the upper and lower surfaces of the lower layer aerogel;

[0015] S12. After uniformly mixing the nanofiber suspension and the carbon nanotube dispersion, a cross-linking agent is added, and the mixture is thoroughly mixed to obtain a second mixed liquid; the second mixed liquid is poured on the upper surface of the lower aerogel layer, and a portion of the second mixed liquid is filled into the through hole. After freeze-drying, an upper aerogel layer is formed that is connected to the lower aerogel layer by mortise and tenon joints, thereby obtaining a Janus composite aerogel having a mortise and tenon structure.

[0016] As a further improvement of the present invention, in step S11, the method of forming the through hole includes:

[0017] A lower layer of aerogel having the through-holes is directly prepared using a predetermined mold, wherein at least one columnar protrusion is provided inside the predetermined mold;

[0018] Alternatively, a lower layer aerogel without through holes is prepared first, and then the lower layer aerogel without through holes is punched.

[0019] As a further improvement of the present invention, in step S11 and step S12, the method for preparing the nanofiber suspension includes: mixing pure nanofibers, deionized water and isopropyl alcohol in a mass ratio of 1:50 to 100:50 to 100, beating the mixture, and stirring thoroughly to obtain a nanofiber suspension; the crosslinking agent is prepared by mixing deionized water, glutaraldehyde and hydrochloric acid in a mass ratio of 5 to 10:1:0.1.

[0020] As a further improvement of the present invention, in step S11, the mass ratio of the nanofiber suspension to the crosslinking agent is 8 to 10:1; and the hydrophobic modification treatment method is: fumigation with methyltrichlorosilane at 40 to 80° C. for 6 to 12 hours.

[0021] As a further improvement of the present invention, in step S12, the method for preparing the carbon nanotube dispersion includes: mixing carbon nanotubes, surfactant and deionized water in a mass ratio of 1 to 5:1:100, then crushing them with a cell crusher for 1 to 2 hours, and then heating them in a water bath at 30 to 80°C for 1 to 3 hours.

[0022] As a further improvement of the present invention, in step S12, the mass ratio of the nanofiber suspension to the carbon nanotube dispersion is 10:1-3; the mass ratio of the total mass of the nanofiber suspension and the carbon nanotube dispersion to the crosslinking agent is 8-10:1.

[0023] The beneficial effects of the present invention are:

[0024] 1. The evaporation and desalination method based on photoacoustic synergy provided by the present invention performs ultrasonic treatment while utilizing light to carry out interfacial evaporation, which can achieve a good desalination effect, effectively solving the salt blockage problem faced by interfacial evaporators such as hydrogels, aerogels, and fabrics during seawater evaporation, and extending the service life of the interfacial evaporators.

[0025] 2. The present invention further improves the interface evaporator itself to prepare a Janus composite aerogel with a mortise and tenon structure. This not only utilizes the upper and lower wettability differences of conventional Janus aerogels to reduce the impact of salt clogging, but also uses a hydrophobic aerogel as the lower aerogel to ensure that the composite aerogel as a whole can float completely independently on the water surface. At the same time, although the upper aerogel is located at the top, the columnar protrusions at its bottom can pass through the through holes in the lower aerogel to contact the water surface and utilize its hydrophilicity to continuously transport water upward, so that the upper aerogel utilizes its photothermal conversion properties to convert solar energy into thermal energy to evaporate water. In this way, the contact between the Janus composite aerogel with a mortise and tenon structure and water can be transformed from conventional three-dimensional contact to point contact, allowing the aerogel to float completely on the water surface, using only the point-shaped columnar protrusions at the bottom for water transfer, greatly avoiding heat loss to the water body and enabling more heat to be used for evaporation in the interface water area. Moreover, since the aerogel is not immersed in a salt solution, the impact of salt blockage can be further reduced to a certain extent, while effectively improving the durability of the aerogel and extending its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the structure of the Janus composite aerogel with a mortise and tenon structure prepared in some embodiments of the present invention.

[0027] Figure 2 Schematic diagram of the structure of the lower layer aerogel in the Janus composite aerogel with a mortise and tenon structure prepared in some embodiments of the present invention.

[0028] Figure 3 Actual pictures of the interfacial evaporator prepared in Example 1 at different time periods during the evaporation process under photoacoustic synergy conditions.

[0029] Figure 4 Actual pictures of the interfacial evaporator prepared in comparative example 1 at different time periods during the evaporation process under photoacoustic synergy conditions.

[0030] Figure 5 This is a physical picture of the Janus composite aerogel with a mortise and tenon structure prepared in Example 2.

[0031] Figure 6 This is a bottom view of the Janus composite aerogel with a mortise and tenon structure prepared in Example 2.

[0032] Reference numerals

[0033] 1-upper aerogel layer; 2-lower aerogel layer. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] It should also be noted here that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0036] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0037] The present invention provides an evaporative desalination method based on photoacoustic synergy, comprising the following steps:

[0038] S1. Prepare an interface evaporator;

[0039] S2. placing the interface evaporator in a saline solution and performing ultrasonic treatment while irradiating with light.

[0040] In step S1, the interfacial evaporator can be an aerogel, a hydrogel, or a fabric. The aerogel can be either conventional aerogel or Janus aerogel. Conventional aerogels are formed by freeze-drying a nanofiber suspension after a thorough reaction with a crosslinker. Janus aerogels, on the other hand, consist of two layers of aerogel with different wettabilities: a lower hydrophilic layer and an upper hydrophobic layer. This type of aerogel can utilize the difference in wettability to reduce the effects of salt clogging.

[0041] More preferably, the present invention further provides a Janus composite aerogel having a mortise and tenon structure, the structural diagram of which is shown in FIG. Figure 1-2 Unlike conventional Janus aerogels, this Janus composite aerogel with a mortise and tenon structure comprises, from top to bottom, a hydrophilic upper aerogel layer 1 and a hydrophobic lower aerogel layer 2. The lower aerogel layer 2 contains through-holes extending through its upper and lower surfaces, and the bottom of the upper aerogel layer 1 contains columnar protrusions that match the through-holes, forming a mortise and tenon structure with the through-holes.

[0042] The preparation method of the Janus composite aerogel having a mortise and tenon structure comprises the following steps:

[0043] S11, fully mixing the nanofiber suspension and the cross-linking agent to obtain a first mixed solution; placing the first mixed solution in a mold, freeze-drying it to form an aerogel, and then performing a hydrophobic modification treatment to obtain a lower layer aerogel 2; the lower layer aerogel 2 contains through holes penetrating the upper and lower surfaces of the lower layer aerogel 2;

[0044] S12. After uniformly mixing the nanofiber suspension and the carbon nanotube dispersion, a cross-linking agent is added, and the mixture is thoroughly mixed to obtain a second mixed liquid; the second mixed liquid is poured onto the upper surface of the lower aerogel 2, and a portion of the second mixed liquid is filled into the through hole. After freeze-drying, an upper aerogel 1 is formed that is connected to the lower aerogel 2 by mortise and tenon joints, thereby obtaining a Janus composite aerogel having a mortise and tenon structure.

[0045] The present invention provides through-holes penetrating the upper and lower surfaces of the lower aerogel layer, and directly pours a mixed liquid for preparing the upper aerogel layer 1 onto the surface of the lower aerogel layer, thereby forming a columnar protrusion at the bottom of the upper aerogel layer 1 that is connected to the through-holes by mortise and tenon joints. The composite aerogel formed under these conditions not only tightly connects the upper and lower aerogel layers 2 via the mortise and tenon joint structure, but also allows the hydrophobic aerogel to serve as the lower aerogel layer 2, ensuring that the composite aerogel as a whole can completely and independently float on the water surface. At the same time, although the upper aerogel layer 1 is located at the top, the columnar protrusions at its bottom can pass through the through-holes in the lower aerogel layer 2 to contact the water surface, and utilize its hydrophilicity to continuously transport water upward, so that the upper aerogel layer 1 utilizes its photothermal conversion properties to convert solar energy into thermal energy to evaporate the water. Through this method, the contact between the Janus composite aerogel with a mortise and tenon structure and water is transformed from conventional three-dimensional contact to point contact, allowing the aerogel to float completely on the water surface. Water is transferred only through the dotted columnar protrusions at the bottom, greatly reducing heat loss to the water body and allowing more heat to be used for evaporation from the interfacial water. Furthermore, since the aerogel is not immersed in a salt solution, the impact of salt clogging can be further reduced to a certain extent, while effectively improving the aerogel's durability and extending its service life.

[0046] More preferably, in the method for preparing the Janus composite aerogel having a mortise and tenon structure, the method for forming the through hole in step S11 includes:

[0047] A lower layer of aerogel 2 having the through-holes is directly prepared using a predetermined mold, wherein at least one columnar protrusion is provided inside the predetermined mold;

[0048] Alternatively, a lower layer aerogel 2 without through holes is prepared first, and then the lower layer aerogel 2 without through holes is punched.

[0049] In steps S11 and S12, the method for preparing the nanofiber suspension includes: mixing pure nanofibers, deionized water, and isopropyl alcohol in a mass ratio of 1:50-100:50-100, beating the mixture, and stirring thoroughly to obtain a nanofiber suspension; the crosslinking agent is prepared by mixing deionized water, glutaraldehyde, and hydrochloric acid in a mass ratio of 5-10:1:0.1; and the mass ratio of the nanofiber suspension to the crosslinking agent is 8-10:1. If the amount of crosslinking agent added is too small, the resulting aerogel is brittle and has extremely poor mechanical properties.

[0050] In step S11, the hydrophobic modification treatment is performed by fumigating the aerogel with methyltrichlorosilane at 40-80°C for 6-12 hours. If the fumigation time is too short, the hydrophobic modification is not thorough enough, and the hydrophobic angle can only reach about 90°. If the modification time is too long, the surface of the aerogel will shrink, and the morphology will be damaged.

[0051] In step S12, the method for preparing the carbon nanotube dispersion includes: mixing carbon nanotubes, a surfactant, and deionized water in a mass ratio of 1 to 5:1:100, crushing with a cell crusher for 1 to 2 hours, and then heating in a water bath at 30 to 80 degrees Celsius for 1 to 3 hours; the mass ratio of the nanofiber suspension to the carbon nanotube dispersion is 10:1 to 3; and the mass ratio of the total mass of the nanofiber suspension and the carbon nanotube dispersion to the crosslinking agent is 8 to 10:1. If the proportion of crosslinking agent is too low, the surface of the freeze-dried aerogel will be bumpy and the mechanical properties will be extremely poor.

[0052] In step S2, the illumination can be natural light, xenon light, or other light sources. The ultrasonic treatment power is 80 to 120 W, and the treatment method is: 3 to 7 minutes of operation followed by 3 to 7 minutes of rest. Under these conditions, a good desalination effect is achieved, effectively solving the salt clogging problem faced by hydrogel, aerogel, and fabric interfacial evaporators during seawater evaporation, and extending the service life of the interfacial evaporators.

[0053] The evaporative desalination method based on photoacoustic synergy provided by the present invention is described in detail below with reference to specific embodiments.

[0054] Example 1

[0055] This embodiment provides an evaporative desalination method based on photoacoustic synergy, comprising the following steps:

[0056] S1. Prepare an interface evaporator. The interface evaporator prepared in this embodiment is an aerogel evaporator, and its preparation method is as follows:

[0057] Pure nanofibers (fiber material is pva-co-pe), deionized water and isopropyl alcohol are mixed in a mass ratio of 1:100:100 and then pulped. After sufficient stirring, a nanofiber suspension is obtained, which is stored for later use; deionized water, glutaraldehyde and hydrochloric acid are mixed in a mass ratio of 10:1:0.1 to form a crosslinking agent, which is stored for later use.

[0058] The nanofiber suspension and the crosslinking agent were mixed and stirred for 2 hours at a mass ratio of 10:1 to obtain a mixed solution. The mixed solution was poured into a mold and rapidly frozen with liquid nitrogen to form a cryogel. The mold was then placed in a freeze dryer and freeze-dried for 48 hours to form an aerogel evaporator.

[0059] S2. Prepare a sodium chloride solution with a concentration of 21 wt% as a saline solution and place it in a beaker. Then, place the aerogel interfacial evaporator obtained in step S1 in the saline solution in the beaker and irradiate it with a xenon lamp with a power of 1 sun. Simultaneously, place the beaker in an ultrasonic machine (ultrasonic power of 100 W) for 120 minutes, with the ultrasonic probe working for 5 minutes and resting for 5 minutes every time, to perform an evaporation experiment.

[0060] Comparative Example 1

[0061] This comparative example provides an interfacial evaporator and evaporation method. The interfacial evaporator is identical to the aerogel evaporator prepared in step S1 of Example 1. The evaporation method is based on step S2 of Example 1, omitting the ultrasonic treatment. A seawater evaporation experiment was conducted under a single illumination condition.

[0062] The aerogel evaporator in the evaporation experiment of Example 1 and Comparative Example 1 was photographed every 30 minutes, and the results were as follows: Figure 3 、 Figure 4 As shown. Figure 3 and Figure 4 It can be seen that compared with the single light treatment in Comparative Example 1, Example 1 can significantly improve the salt blockage problem in the evaporation process by coordinating the ultrasonic treatment, and effectively extend the service life of the interface evaporator.

[0063] The desalination rate of Example 1 was calculated by quantitative analysis to be 56%, and the water evaporation rate was 2.0 kg·m -2 h -1 , the photothermal conversion efficiency is 66%; the desalination rate of comparative example 1 is 34%, and the water evaporation rate is 1.4 kg·m -2 h -1 , the photothermal conversion efficiency is 42%.

[0064] According to the above results, it can be seen that the ultrasonic treatment provided in Example 1 can effectively improve the desalination rate, thereby improving the water evaporation rate and the photothermal conversion efficiency.

[0065] Example 2

[0066] This embodiment provides an evaporative desalination method based on photoacoustic synergy. Compared with Example 1, the only difference is that the structure of the interface evaporator in step S1 and its preparation method are changed. Step S2 is completely consistent with Example 1 and will not be repeated here.

[0067] In this embodiment, the interface evaporator is a conventional Janus aerogel, and its preparation method specifically includes the following steps:

[0068] S11. Pure nanofibers (fiber material is pva-co-pe), deionized water and isopropyl alcohol are mixed in a mass ratio of 1:100:100 and then beaten. After sufficient stirring, a nanofiber suspension is obtained, which is stored for later use; deionized water, glutaraldehyde and hydrochloric acid are mixed in a mass ratio of 10:1:0.1 to form a cross-linking agent, which is stored for later use.

[0069] The nanofiber suspension and crosslinker were mixed and stirred for 2 hours at a mass ratio of 10:1 to obtain a first mixed solution. This first mixed solution was then placed in a mold without columnar protrusions. The mold containing the first mixed solution was first rapidly frozen with liquid nitrogen to form a cryogel, which was then freeze-dried in a freeze dryer for 48 hours to form an aerogel. The aerogel was then fumigated with methyltrichlorosilane at 60°C for 12 hours to perform a hydrophobic modification. The resulting hydrophobic aerogel served as the upper layer aerogel.

[0070] S12, carbon nanotubes, surfactants and deionized water are mixed in a mass ratio of 3:1:100, crushed with a cell crusher for 2 hours, and then heated in a water bath at 70°C for 1 hour to obtain a carbon nanotube dispersion. The nanofiber suspension prepared in step S1 is mixed with the carbon nanotube dispersion in a mass ratio of 10:1, and then the crosslinker prepared in step S1 is added so that the total mass of the nanofiber suspension and the carbon nanotube dispersion is 10:1 to the mass ratio of the crosslinker. After mixing and stirring for 2 hours, a second mixed solution is obtained. The upper layer of aerogel is then placed in a mold without columnar protrusions, and the second mixed solution is poured on the surface of the upper layer of aerogel. After rapid freezing with liquid nitrogen, it is placed in a freeze dryer and freeze-dried for 48 hours. The hydrophilic aerogel layer formed on the surface of the upper layer of aerogel serves as the lower layer of aerogel, obtaining a Janus aerogel with different wettability at the top and bottom.

[0071] The test results show that the desalination rate of the interface evaporator prepared in this embodiment during the evaporation experiment is 65%, and the water evaporation rate is 2.3 kg·m -2 h -1 , the photothermal conversion efficiency is 72%. Compared with Example 1, it can be seen that conventional Janus aerogel has more advantages than ordinary aerogel in desalination.

[0072] Example 3

[0073] This embodiment provides an evaporative desalination method based on photoacoustic synergy. Compared with Example 1, the only difference is that the structure of the interface evaporator in step S1 and its preparation method are changed. Step S2 is completely consistent with Example 1 and will not be repeated here.

[0074] In this embodiment, the interface evaporator is a Janus composite aerogel with a mortise and tenon structure, and its preparation method specifically includes the following steps:

[0075] S11. Pure nanofibers (fiber material is pva-co-pe), deionized water and isopropyl alcohol are mixed in a mass ratio of 1:100:100 and then beaten. After sufficient stirring, a nanofiber suspension is obtained, which is stored for later use; deionized water, glutaraldehyde and hydrochloric acid are mixed in a mass ratio of 10:1:0.1 to form a cross-linking agent, which is stored for later use.

[0076] A nanofiber suspension and a crosslinker were mixed and stirred for 2 hours at a mass ratio of 10:1 to obtain a first mixed liquid. This first mixed liquid was then placed in a predetermined mold with two columnar protrusions. The mold containing the first mixed liquid was first rapidly frozen with liquid nitrogen to form a cryogel, which was then freeze-dried in a freeze dryer for 48 hours to form an aerogel. The aerogel was then fumigated with methyltrichlorosilane at 60°C for 12 hours to perform a hydrophobic modification, yielding a lower layer of aerogel. This lower layer of aerogel contained through-holes extending through the upper and lower surfaces of the lower layer of aerogel.

[0077] S12. Mix carbon nanotubes, surfactants and deionized water in a mass ratio of 3:1:100, crush them with a cell crusher for 2 hours, and then heat them in a water bath at 70°C for 1 hour to obtain a carbon nanotube dispersion. Mix the nanofiber suspension prepared in step S1 with the carbon nanotube dispersion in a mass ratio of 10:1, then add the cross-linking agent prepared in step S1 to make the total mass of the nanofiber suspension and the carbon nanotube dispersion to the mass ratio of the cross-linking agent be 10:1, and mix and stir for 2 hours to obtain a second mixed solution. Then place the lower layer of aerogel in a mold that does not contain columnar protrusions inside, pour the second mixed solution on the upper surface of the lower layer of aerogel, and fill a portion of the second mixed solution into the through hole. First, freeze it rapidly with liquid nitrogen, and then place it in a freeze dryer for freeze drying for 48 hours to obtain a Janus composite aerogel with a mortise and tenon structure. The actual figure is as shown in the figure below. Figure 5-6 shown.

[0078] The test results show that the desalination rate of the interface evaporator prepared in this embodiment during the evaporation experiment is 80%, and the water evaporation rate is 3.0 kg·m -2 h -1, the photothermal conversion efficiency is 85%. Compared with Example 2, it can be seen that the Janus composite aerogel with a mortise and tenon structure designed in the present invention has better desalination performance than the conventional Janus aerogel.

[0079] In summary, the present invention provides an evaporative desalination method based on photoacoustic synergy, comprising preparing an interfacial evaporator, placing the interfacial evaporator in a saline solution, and performing ultrasonic treatment while irradiating with light. Through the above-mentioned method, a better desalination effect can be achieved, effectively solving the problem of salt blockage faced by interfacial evaporators such as hydrogels, aerogels, and fabrics during the evaporation of seawater, and extending the service life of the interfacial evaporator. The present invention also improves the interfacial evaporator itself to prepare a Janus composite aerogel with a mortise and tenon structure, which can not only utilize the difference in wettability between the upper and lower parts to reduce the impact of salt blockage, but also can float completely independently on the water surface, transforming the contact with water from three-dimensional to point contact, effectively improving the evaporation efficiency; and the composite aerogel will not be immersed in a saline solution, which can further reduce the impact of salt blockage to a certain extent, while effectively improving the durability of the aerogel and extending its service life.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. An evaporative desalination method based on photoacoustic synergy, characterized in that: The steps include: S1. Prepare an interface evaporator; S2. placing the interface evaporator in a saline solution and performing ultrasonic treatment while irradiating with light.

2. The evaporative desalination method based on photoacoustic synergy according to claim 1, characterized in that: In step S2, the power of the ultrasonic treatment is 80-120W, and the treatment method is: work for 3-7 minutes and rest for 3-7 minutes.

3. The evaporative desalination method based on photoacoustic synergy according to claim 1, characterized in that: In step S1, the interface evaporator includes one of aerogel, hydrogel, and fabric.

4. The evaporative desalination method based on photoacoustic synergy according to claim 3, characterized in that: In step S1, the interface evaporator is a Janus composite aerogel with a mortise and tenon structure; the Janus composite aerogel with a mortise and tenon structure includes, from top to bottom, an upper aerogel with hydrophilicity and a lower aerogel with hydrophobicity; the interior of the lower aerogel contains a through hole that penetrates the upper and lower surfaces of the lower aerogel, and the bottom of the upper aerogel contains a columnar protrusion that matches the through hole, and the columnar protrusion forms a mortise and tenon structure with the through hole.

5. The evaporative desalination method based on photoacoustic synergy according to claim 4, characterized in that: The preparation method of the Janus composite aerogel with a mortise and tenon structure comprises the following steps: S11, fully mixing the nanofiber suspension with the cross-linking agent to obtain a first mixed solution; placing the first mixed solution in a mold, freeze-drying it to form an aerogel, and then performing a hydrophobic modification treatment to obtain a lower layer aerogel; the lower layer aerogel comprises through holes penetrating the upper and lower surfaces of the lower layer aerogel; S12. After uniformly mixing the nanofiber suspension and the carbon nanotube dispersion, a cross-linking agent is added, and the mixture is thoroughly mixed to obtain a second mixed liquid; the second mixed liquid is poured on the upper surface of the lower aerogel layer, and a portion of the second mixed liquid is filled into the through hole. After freeze-drying, an upper aerogel layer is formed that is connected to the lower aerogel layer by mortise and tenon joints, thereby obtaining a Janus composite aerogel having a mortise and tenon structure.

6. The evaporative desalination method based on photoacoustic synergy according to claim 5, characterized in that: In step S11, the method of forming the through hole includes: A lower layer of aerogel having the through-holes is directly prepared using a predetermined mold, wherein at least one columnar protrusion is provided inside the predetermined mold; Alternatively, a lower layer aerogel without through holes is prepared first, and then the lower layer aerogel without through holes is punched.

7. The evaporative desalination method based on photoacoustic synergy according to claim 5, characterized in that: In step S11 and step S12, the method for preparing the nanofiber suspension includes: mixing pure nanofibers, deionized water and isopropyl alcohol in a mass ratio of 1:50 to 100:50 to 100, beating the mixture, and stirring the mixture sufficiently to obtain a nanofiber suspension; the crosslinking agent is prepared by mixing deionized water, glutaraldehyde and hydrochloric acid in a mass ratio of 5 to 10:1:0.

1.

8. The evaporative desalination method based on photoacoustic synergy according to claim 5, characterized in that: In step S11, the mass ratio of the nanofiber suspension to the cross-linking agent is 8 to 10:1; and the hydrophobic modification treatment method is: fumigating with methyltrichlorosilane at 40 to 80° C. for 6 to 12 hours.

9. The evaporative desalination method based on photoacoustic synergy according to claim 5, characterized in that: In step S12, the preparation method of the carbon nanotube dispersion includes: mixing carbon nanotubes, surfactant and deionized water in a mass ratio of 1-5:1:100, crushing with a cell crusher for 1-2 hours, and then heating in a water bath at 30-80°C for 1-3 hours.

10. The evaporative desalination method based on photoacoustic synergy according to claim 5, characterized in that: In step S12, the mass ratio of the nanofiber suspension to the carbon nanotube dispersion is 10:1-3; the mass ratio of the total mass of the nanofiber suspension and the carbon nanotube dispersion to the crosslinking agent is 8-10:1.

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