A brine evaporation power generation hydrogel and a preparation method and application thereof

Abstract

The application discloses a kind of brine evaporation power generation hydrogel and its preparation method and application, belong to energy power generation technical field.Polyelectrolyte polystyrene sulfonic acid sodium (PNaSS) is used, and its microstructure presents "brush-like" structure, when the hydrogel (HPH) prepared is immersed in high concentration brine, a large number of salt ions pass through the polyelectrolyte brush channel, because PNaSS chain itself has negative charge, more easily attract sodium ion Na + The material in the application has low cost and simple preparation, and the thermal gradient generated by the hydrogel under light can induce water evaporation, thereby driving ion selective through the charged channel. The application uses a power-free, environmentally friendly and economical way to carry out seawater desalination and evaporation power generation, making the evaporation efficiency and power generation capacity stronger, which has important significance for realizing solar steam and water evaporation power generation in seawater.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energy power generation, and particularly relates to a saltwater evaporation power generation hydrogel as well as a preparation method and application thereof. BACKGROUND

[0002] Since the 20th century, energy crisis and fresh water crisis are two key problems to be solved in the world, and using solar energy and environmental energy to obtain steam and electricity from seawater provides a new strategy for solving these problems. Generally, the power generation from seawater is to utilize its kinetic energy and potential energy, such as tidal energy, wave energy, etc., but the large equipment required is expensive, and the power generation stability is poor, and meanwhile, the environmental problems caused by more fossil fuel combustion will become increasingly serious. On the other hand, the current mature seawater desalination methods involve thermal distillation desalination and reverse osmosis desalination, etc., wherein the thermal distillation method has a high operation cost due to the complicated seawater circulation and fluid transportation process; and the most critical problem in the reverse osmosis method is that the permeation membrane needs to be regularly manually managed and maintained and cleaned, and large high-pressure equipment is involved for pumping seawater. Therefore, developing a small and inexpensive seawater desalination and power generation device is a low-cost, green and sustainable development approach.

[0003] Solar energy is a kind of inexhaustible renewable energy, and using solar energy as the only power source for seawater desalination has low energy consumption, simple operation and no pollution, which is a very promising technology. In the past decade, there have been numerous studies on interfacial solar evaporation devices, and scholars have proposed various strategies to avoid salt accumulation and crystallization on the surface of the evaporation device, such as controlling the seawater transportation route to limit salt crystallization at the edge of the material, or introducing large-size channels to improve water replenishment to improve salt resistance, thereby greatly improving the evaporation rate in concentrated salt water.

[0004] Water evaporation occurs spontaneously in nature at all times, and research on generating electricity from water evaporation has been reported. Evaporation-driven power generation mainly utilizes the directional transport of water through evaporation. Due to the double layer effect, the flow of water in micro- and nano-channels drives the movement of counterions, thereby generating a potential difference. Solar interface evaporation based on porous media can provide the power and large specific surface area for water transport in micro-channels. However, previous reports on evaporation-driven power generation have been limited to deionized water or low-concentration saline. For example, Zhou et al. studied the water evaporation process on the surface of nano-carbon materials, which can induce the generation of electricity, but only discussed the relevant mechanisms and performance in deionized water, which has certain limitations (Nature Nanotechnology 12, 317–321 (2017)). Zhou et al. designed a fully printed porous carbon membrane for evaporation power generation, which has the advantages of simple structure, low cost, and easy scalability, but the drawback is that it did not further consider the feasibility of application in seawater of different concentrations (Adv. Funct. Mater. 2017, 1700551). Qu et al. precisely adjusted Al 3+ with Ni 2+ Ni-Al layered double hydroxide films synthesized at a specific molar ratio can generate electricity through natural water evaporation, but the maximum open-circuit voltage produced is relatively small, and the output power is low (Nano Energy 2020, 70, 104502). Therefore, developing power generation devices that realize high-concentration brine evaporation power generation remains an important challenge.

[0005] In recent years, much research has been conducted on seawater desalination and evaporative power generation, but most of these efforts have been independent. One important reason for this is that the voltage drops rapidly, even approaching zero, as the salt concentration increases. When a solid surface comes into contact with salt water, the surface charge attracts a large number of counterions, forming an ion cloud on the material surface. This large number of ions compresses the electric field formed on the material surface into a smaller "sheath," causing the Debye length to decrease rapidly and thus the zeta potential to drop. Based on this, various strategies have been proposed to increase the power of the water voltaic effect in salt water, such as adjusting the pH value of the salt water to deviate from the isoelectric point of the material, or reducing the channel size to make the channel radius smaller than the Debye radius. However, these methods are complex to operate, and small channels make it easier for salt to accumulate and crystallize. Therefore, a new strategy is needed to simultaneously generate steam and electricity in seawater. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a brine evaporation power generation hydrogel, its preparation method and application, to solve the technical problems that the prior art is limited to working in deionized water or low-concentration brine, and that seawater evaporation power generation is complicated in operation.

[0007] To achieve the above object, the present application adopts the following technical solutions to achieve the above object:

[0008] 2. The application discloses a preparation method of a salt water evaporation power generation hydrogel, comprising the following steps:

[0009] S1: stirring and mixing a sodium poly (p-styrenesulfonate) solution, a poly (3-methyl-2-methylacrylamido-ammonium chloride) solution and deionized water to obtain a PIC complex;

[0010] S2: immersing the PIC complex into a mixed solution composed of phytic acid and aniline to obtain a PIC complex after polymerization of aniline monomers;

[0011] S3: mixing the PIC complex after polymerization of aniline monomers and an ammonium persulfate aqueous solution to react, obtaining a reaction product after the reaction, and washing the reaction product to obtain the salt water evaporation power generation hydrogel.

[0012] Further, in S1, the sodium poly (p-styrenesulfonate) solution is composed of sodium poly (p-styrenesulfonate) and deionized water; and the poly (3-methyl-2-methylacrylamido-ammonium chloride) solution is composed of poly (3-methyl-2-methylacrylamido-ammonium chloride) and deionized water.

[0013] The concentration of the sodium poly (p-styrenesulfonate) solution and the poly (3-methyl-2-methylacrylamido-ammonium chloride) solution is 0.1-0.5M.

[0014] Further, the preparation method of the sodium poly (p-styrenesulfonate) comprises the following steps: mixing sodium p-styrenesulfonate and alpha-ketoglutaric acid, irradiating under ultraviolet light to obtain a mixed solution A; pouring the mixed solution A into anhydrous ethanol to precipitate, obtaining precipitate A, and drying the precipitate A to obtain the sodium poly (p-styrenesulfonate).

[0015] The preparation method of the poly (3-methyl-2-methylacrylamido-ammonium chloride) comprises the following steps: mixing 3-methyl-2-methylacrylamido-ammonium chloride and alpha-ketoglutaric acid, irradiating under ultraviolet light to obtain a mixed solution B; pouring the mixed solution B into anhydrous ethanol to precipitate, obtaining precipitate B, and drying the precipitate B to obtain the poly (3-methyl-2-methylacrylamido-ammonium chloride).

[0016] Further, the ultraviolet light is characterized by 365nm and 7.5mW / cm 2The irradiation time is 8-10h; the molar percentage of alpha-ketoglutaric acid and sodium p-styrenesulfonate is 0.1mol%; the molar percentage of alpha-ketoglutaric acid and 3-methyl 2-methyl acrylamido-ammonium chloride is 0.1mol%; the drying temperature is 80-100 DEG C, and the drying time is 12-24h.

[0017] Further, in S1, the volume ratio of the sodium poly-p-styrenesulfonate solution, the poly-3-methyl 2-methyl acrylamido-ammonium chloride solution and the deionized water is (100-110):(100-110):200; the stirring time is 30-40min.

[0018] Further, in S2, the molar concentration of phytic acid and aniline in the mixed solution is 0.05M and 0.25M respectively.

[0019] Further, in S2, the volume ratio of the sodium poly-p-styrenesulfonate solution and the mixed solution is (100-110):250.

[0020] Further, in S3, the volume ratio of the sodium poly-p-styrenesulfonate solution and the ammonium persulfate aqueous solution is (100-110):250; the concentration of the ammonium persulfate aqueous solution is 0.125M.

[0021] The application further discloses the water evaporation power generation hydrogel prepared by the preparation method.

[0022] The application further discloses the application of the water evaporation power generation hydrogel, and the salt water evaporation power generation hydrogel is used as an additive in a seawater evaporation power generation process.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] The application discloses a preparation method of a salt water evaporation power generation hydrogel. + Moreover, the benzene ring in the PNaSS molecular chain makes the PNaSS have harder "bristles", which leads to the fact that the PNaSS chain is more likely to attract sodium ions Na +The material is constrained between the "bristles", that is, "overscreening" occurs, the charge sign of the channel surface is reversed, that is, positive electricity is presented. At this time, the channel will attract negative ions into the channel, and the continuous passage of a large number of counterions can generate a streaming potential, thereby achieving the remarkable effect of evaporation power generation in high-concentration salt water. Compared with existing carbon nanotubes, graphene, carbon nanoparticles and graphene-based metal composites, the material in the application has low cost and simple preparation, and the thermal gradient generated by the hydrogel under light can induce water evaporation, thereby driving the selective passage of ions through the charged channel. The seawater desalination and evaporation power generation are carried out in a power-free, environmentally friendly and economical way, which is more efficient in evaporation and power generation capacity, and has important significance for realizing solar steam and water evaporation power generation in seawater.

[0025] The application further discloses a salt water evaporation power generation hydrogel (HPH) prepared by the preparation method, the seawater desalination efficiency and water power generation capacity are greatly improved by using the HPH hydrogel which is rich in hydrophilic groups and has an ultra-wide pore size distribution range, and the HPH has super strong hydrophilicity and water transport rate, which is mainly due to the rich hydrophilic groups on the surface of the HPH, such as C=O, -C-O and -OH, the water effect is improved, the phenomenon of salt analysis on the evaporation surface is eliminated, and the cost and manpower problems caused by the replacement of the hydrogel due to the reduction of the performance of the hydrogel are minimized, so that the seawater and concentrated salt water can be desalinated to produce low-price drinking water, and the high evaporation performance can be maintained for a long time.

[0026] The application further discloses application of the hydrogel in solar seawater desalination and evaporation power generation, and provides a low-cost and very simple preparation process, which is used as a core component to realize integration of solar steam and flow power generation in salt water, can be applied to daily small-scale power generation equipment, has high economic benefits and social value, and has wide development prospect. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The open-circuit voltage and short-circuit current diagram of the HPH hydrogel prepared in the embodiment 1 of the application during evaporation power generation is shown in the figure;

[0028] Figure 2 The structure diagram of poly 3-methyl 2-methyl acrylamide ammonium chloride (PMPTC) and poly sodium p-styrenesulfonate (PNaSS) in the HPH hydrogel prepared in the embodiment 1 of the application is shown in the figure;

[0029] Figure 3 The SEM diagram of the HPH hydrogel prepared in the embodiment 1 of the application is shown in the figure;

[0030] Wherein: a-500 mu m; b-5 mu m;

[0031] Figure 4 Open circuit voltage of HPH hydrogel prepared in Example 2 of the present application at different temperatures;

[0032] Figure 5 Open circuit voltage of HPH hydrogel prepared in Example 3 of the present application at different humidity;

[0033] Figure 6 Open circuit voltage and Zeta potential of HPH hydrogel prepared in Example 4 of the present application at different salt concentration;

[0034] Figure 7 Power generation performance of HPH hydrogel prepared in Example 5 of the present application at different light intensity;

[0035] Figure 8 Mass change and voltage of HPH hydrogel prepared in Example 6 of the present application in simulated seawater;

[0036] Figure 9 Voltage change of HPH hydrogel prepared in Example 7 of the present application when connected in series with different number of devices;

[0037] Figure 10 Actual picture of HPH hydrogel prepared in Example 7 of the present application when six devices are connected in series to power a small calculator;

[0038] Figure 11 Variation trend of temperature, voltage and power density during outdoor experiment in Example 8 of the present application. DETAILED DESCRIPTION

[0039] To enable persons skilled in the art to understand the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have their usual meanings understood by those skilled in the art of the present application, and in case of conflict, the definition in the specification shall prevail.

[0040] Theories or mechanisms described and disclosed herein, whether correct or not, should not be considered limiting the scope of the present application, i.e., the present application can be practiced without regard to any particular theory or mechanism.

[0041] Herein, all features defined in the form of numerical ranges or percentage ranges, such as values, amounts, contents and concentrations, are for the sake of brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual values within the range (including integers and fractions).

[0042] In the present specification, unless particularly stated, "comprising", "including", "containing", "having" or like terms means "consisting essentially of and "consisting essentially of", for example, "A comprising a" means "A comprising a and other" and "A consisting of a".

[0043] In the present specification, all possible combinations of the various technical features in the various embodiments or examples are not described in order to make the description concise. Therefore, as long as the combinations of the technical features do not contradict each other, the technical features in the various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered as falling within the scope of the present specification.

[0044] The present application is further described in detail by the following specific examples. It is to be understood that these examples are intended to illustrate the application and that changes can be variously made in the application by those skilled in the art without departing from the scope of the application. In addition, it should be understood that where I have not specifically followed the traditional order of steps in the construction of the compositions of the present application, the skilled artisan will appreciate that such order is set forth herein for illustrative purposes only and is not to be taken in a limiting sense.

[0045] The following examples use conventional equipment in the art. The following examples use conventional equipment in the art. The experimental methods in the following examples, unless otherwise specified, are generally carried out under conventional conditions, or under the conditions recommended by the manufacturer. The following examples use various raw materials, unless otherwise specified, all use conventional commercially available products, the specifications are conventional specifications in the art. In the specification of the present application and in the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0046] Example 1

[0047] A method for preparing a salt water evaporation power generation hydrogel, comprising the following steps:

[0048] S1: 22.91 g of sodium p-styrenesulfonate (NaSS) powder with a purity of 90% and 41.93 mL of 3-methyl 2-methyl acrylamido-ammonium chloride (MPTC) solution with a purity of 50% were added to 100 mL of deionized water, respectively, to obtain a sodium p-styrenesulfonate (NaSS) solution with a concentration of 1 M and a 3-methyl 2-methyl acrylamido-ammonium chloride (MPTC) solution with a concentration of 1 M, then 0.05 mol% of α-ketoglutaric acid was added as an initiator, and then irradiated under 365 nm, 7.5 mW / cm 2 ultraviolet light for 8 h to obtain mixed solution A and mixed solution B; the mixed solution A, the mixed solution B were poured into anhydrous ethanol for precipitation to remove the NaSS and MPTC that were not completely polymerized. The obtained precipitate was placed in an electric heating air drying oven at 80°C for drying for 24 h to finally obtain PNaSS and PMPTC powders;

[0049] The PNaSS and PMPTC powders obtained above were respectively dissolved in deionized water to obtain a PNaSS solution and a PMPTC solution with a concentration of 0.1 M (relative to monomers); 100 mL of the PNaSS solution and 100 mL of the PMPTC solution were slowly added into 200 mL of deionized water, and stirring was continued for 30 min, and the PNaSS and PMPTC powders were spontaneously polymerized by electrostatic interaction, and the PNaSS and PMPTC powders were left to stand at room temperature for 2 h to self-assemble into a stable white polyion complex, i.e., a PIC complex;

[0050] S2: The PIC complex obtained was immersed in a 250-mL mixed solution of phytic acid and aniline to obtain a PIC complex after polymerization of aniline monomers; the molar concentrations of phytic acid and aniline in the mixed solution were 0.05 M and 0.25 M, respectively;

[0051] S3: The PIC complex after polymerization of aniline monomers obtained was mixed with 250 mL of an ammonium persulfate aqueous solution with a concentration of 0.125 M to perform a reaction, and a reaction product was obtained after the reaction; the reaction product was dialyzed in a large amount of deionized water to wash away excess acid and byproducts, and a salt water evaporation power hydrogel (HPH) was obtained.

[0052] Example 2

[0053] A method for preparing a salt water evaporation power hydrogel, comprising the following steps:

[0054] S1: 22.91 g of sodium p-styrenesulfonate (NaSS) powder with a purity of 90% and 41.93 mL of 3-methyl 2-methyl acrylamido-ammonium chloride (MPTC) solution with a purity of 50% were respectively added into 100 mL of deionized water to obtain a sodium p-styrenesulfonate (NaSS) solution with a concentration of 1 M and a 3-methyl 2-methyl acrylamido-ammonium chloride (MPTC) solution with a concentration of 1 M, and then 0.1 mol% of α-ketoglutaric acid was added as an initiator, and the solutions were irradiated under ultraviolet light with a wavelength of 365 nm and an intensity of 7.5 mW / cm 2 for 10 h to obtain mixed solution A and mixed solution B; the mixed solution A and the mixed solution B were poured into anhydrous ethanol to precipitate, and the NaSS and MPTC that were not completely polymerized were removed, and the obtained precipitate was placed in a 100°C electric heating air drying oven to dry for 12 h to finally obtain PNaSS and PMPTC powders;

[0055] The PNaSS and PMPTC powders obtained above were dissolved in deionized water respectively to obtain PNaSS solution and PMPTC solution with a concentration of 0.5 M (relative to monomer); 110 mL of the PNaSS solution and 110 mL of the PMPTC solution were slowly added into 200 mL of deionized water, and stirring was continued for 40 min, and the PNaSS and PMPTC powders spontaneously polymerized by electrostatic interaction, and the PNaSS and PMPTC powders were left to stand at room temperature for 2 h to self-assemble into a stable white polyion complex, i.e., a PIC complex;

[0056] S2: The PIC complex obtained was immersed in a mixed solution of 250 mL of phytic acid and aniline to obtain a PIC complex after polymerization of aniline monomers; the molar concentration of the phytic acid and the aniline in the mixed solution was 0.05 M and 0.25 M respectively;

[0057] S3: The PIC complex after polymerization of aniline monomers obtained was mixed with 250 mL of an aqueous solution of ammonium persulfate with a concentration of 0.125 M to perform a reaction, and a reaction product was obtained after the reaction; the reaction product was put into a large amount of deionized water to perform dialysis, and the excess acid and by-products were washed away to obtain a hydrogel (HPH) for evaporation power generation.

[0058] Application Example 1

[0059] The HPH hydrogel prepared in the example was tested for evaporation power generation performance in deionized water, and the specific steps were as follows:

[0060] The HPH hydrogel with a thickness of about 2 mm was cut into a block with an area of 4 cm x 1 cm, and copper foil electrodes with a width of 5 mm were used to paste the upper and lower ends to a polytetrafluoroethylene (PT) plate, and then the side was inclined at an angle of 60° and immersed in deionized water with an immersion depth just reaching the lower electrode, and the open-circuit voltage and short-circuit current generated over a long period of time were measured, as shown in FIG. 1. Figure 1 As shown in FIG. 1, the open-circuit voltage V oc was about 160 mV, and the short-circuit current I sc was 0.3 μA.

[0061] The inclination angle of 60° was set to maximize the transportation of water from the lower block to the upper end by capillary action to ensure the directional and continuous transportation of water and ions.

[0062] Figure 2 FIG. 1 is a structural schematic diagram of poly 3-methyl 2-methyl acrylamide ammonium chloride (PMPTC) and poly p-styrenesulfonic acid sodium (PNaSS) in the HPH hydrogel prepared in Example 1, Figure 3 FIG. 2 is a SEM top view of the HPH hydrogel obtained in Example 1, and Figure 2 and Figure 3It can be seen that the hydrogel has high porosity, large specific surface area, rich surface charge and good hydrophilicity. Polyaniline (PAni) is introduced into PIC as a light absorbing material, forming a new polyelectrolyte porous hydrogel, which improves the light absorption efficiency and mechanical properties of the hydrogel.

[0063] The evaporation power generation performance of the evaporation power generation device in Example 1 was measured at different ambient temperatures, and the specific steps were as follows:

[0064] The humidity was kept constant (RH = 80%) in the constant temperature and humidity chamber, and different ambient temperatures (25℃, 35℃, 45℃, 55℃, 65℃) were changed, as shown in Figure 4 , it can be seen that the open circuit voltage V oc is 82mV, 96mV, 128mV, 160mV, 160mV, respectively. It can be seen that the water evaporation rate has a significant effect on the evaporation power generation performance. The increase of ambient temperature is more conducive to water evaporation, resulting in the continuous increase of V oc , but when the temperature exceeds 55℃, V oc no longer increases, which may be due to the balance between the evaporation rate and the amount of water transported by capillary force.

[0065] The evaporation power generation performance of the evaporation power generation device in Example 1 was measured at different ambient humidities, and the specific steps were as follows:

[0066] The temperature was kept constant (T = 25℃) in the constant temperature and humidity chamber, and different ambient humidities (50%RH, 60%RH, 70%RH, 80%RH, 90%RH, 100%RH) were changed, as shown in Figure 5 , the open circuit voltage is 104mV, 100mV, 97mV, 89mV, 62mV, 30mV, respectively. It can be seen that when the ambient humidity increases, that is, the vapor partial pressure in the environment increases, resulting in a decrease in the driving force for evaporation. Therefore, V oc will decrease rapidly with the increase of ambient RH.

[0067] The open circuit voltage and Zeta potential of the evaporation power generation device in Example 1 were measured in different mass fractions of NaCl (0, 2%, 4%, 6%, 8%) electrolyte, as shown in Figure 6The open circuit voltage is 220 mV, -25 mV, -30 mV, -69 mV, and -65 mV, respectively, and the Zeta potential is -72 mV, 28 mV, 36 mV, 40 mV, and 32 mV, respectively. It can be seen that when the evaporation power generation is used in salt water, the sign of the generated voltage is reversed as the salt water concentration increases. In this process, the direction of the electrode is not changed, and the bottom electrode is the positive electrode, while the top electrode is the negative electrode. This is because the surface charge of the material in the salt water is reversed. When the HPH is immersed in pure water, due to the evaporation at the top, the ions at the lower end will move upward with the water flow. In pure water, the small amount of OH- and H3O + that are dissociated in water follow the water flow. The channel with a negative surface charge repels OH- with the same charge, and attracts counterions with a positive charge into the channel. When the HPH is immersed in salt water, a large number of ions pass through the polyelectrolyte brush channel, and PNaSS is more likely to attract Na + , and PNaSS has harder "bristles" due to the presence of benzene rings. This will cause excess Na + to be trapped between the "bristles", that is, overscreening occurs, and the channel surface charge sign is reversed, that is, the Zeta potential is positive.

[0068] The flow potential, flow current, and power density of the evaporation power generation device in Application Example 1 under different light intensities (0, 0.5 kW·m -2 , 1.0 kW·m -2 , and 1.5 kW·m -2 ) were measured, and the results are shown in Table 1. Figure 7 As shown in Table 1, the flow potential varies between 150 mV and 240 mV, the flow current varies between 0 and 5 μA, and the power density ranges from 0 to 1.3 μW·cm -2 . It can be seen that the generated flow potential, flow current, and power density all have a positive correlation with the light intensity, and excellent power generation effect is exhibited.

[0069] Application Example 2

[0070] A device capable of simultaneously generating electricity and fresh water was designed using the HPH hydrogel prepared in Example 1, and the performance in simulated seawater (about 4 wt% NaCl) was tested. The specific operation steps are as follows:

[0071] The HPH was cut into a block with a size of 3 cm x 6 cm and bent into an L shape, and then a piece of PS foam was placed as a heat insulation layer and a support between the HPH and the water, so that the entire device can float on the water surface.

[0072] The two copper electrodes on both sides are used to collect the generated electricity.

[0073] One end of the HPH was immersed in water, so that water could be transported directionally in the HPH. The evaporation rate and power generation performance of the HPH in pure water and simulated seawater were tested, as shown in Figure 8 The test of water-power cogeneration in saltwater was carried out by the device, and the evaporation rate of the HPH in pure water was only 1.9 kg·m -2 ·h -1 , and in 4% wt simulated seawater, it could reach 2.5 kg·m -2 ·h -1 . Its higher evaporation rate exceeded the theoretical maximum evaporation rate (1.47 kg·m -2 ·h -1 ), because the vibration energy of the hydrogen bond in water was lower in the HPH, and the generated hydrogen bond was more unstable. Therefore, it required smaller vaporization enthalpy for its evaporation. At the same time, a voltage of 50 mV could be generated under a light power density of 1 Sun, and a voltage of 30 mV could be generated even in dark conditions.

[0074] In the HPH, the voltage change when different numbers of devices obtained by application example 2 were connected in series was tested, as shown in Figure 9 As can be seen from Figure 9 , the generated voltage increased by a multiple, and the voltage output did not have obvious fluctuations over time, having good stability; and when six devices were connected in series, it could power a small calculator, as shown in Figure 10 As can be seen from Figure 10 , it has excellent practicability and convenience.

[0075] Six devices obtained by application example 2 were connected in series and placed outdoors for testing for 14 hours, and the change trends of temperature, voltage and power density were observed, as shown in Figure 11 As can be seen, the voltage and power density generated in one day have a close correlation with the environmental temperature, showing excellent potential in actual outdoor applications.

[0076] The above merely illustrates the technical idea of the present application, and cannot limit the protection scope of the present application, and any modification made according to the technical idea of the present application on the basis of the technical solution falls within the protection scope of the claims of the present application.

Claims

1. A method for preparing a salt water evaporation hydrogel for power generation, characterized in that, Includes the following steps: S1: A PIC complex is obtained by stirring and mixing sodium poly(p-styrene sulfonate) solution, poly(3-methyl-2-methyl-enacrylamide-ammonium chloride) solution, and deionized water; the volume ratio of sodium poly(p-styrene sulfonate) solution, poly(3-methyl-2-methyl-enacrylamide-ammonium chloride) solution, and deionized water is (100~110):(100~110):200; the stirring time is 30~40 min; S2: The PIC complex is immersed in a mixed solution of phytic acid and aniline to obtain the PIC complex after polymerization of aniline monomer; the molar concentrations of phytic acid and aniline in the mixed solution are 0.05M and 0.25M, respectively. S3: The PIC complex obtained after polymerizing aniline monomers is mixed with an aqueous solution of ammonium persulfate and reacted. After the reaction is completed, the reaction product is obtained. The reaction product is washed to obtain a salt water evaporation hydrogel.

2. The method for preparing a saltwater evaporation hydrogel for power generation according to claim 1, characterized in that, In S1, the sodium poly(p-styrene sulfonate) solution is composed of a mixture of sodium poly(p-styrene sulfonate) and deionized water; the poly(3-methyl-2-methylenylacrylamide-ammonium chloride) solution is composed of a mixture of poly(3-methyl-2-methylenylacrylamide-ammonium chloride) and deionized water. The concentrations of the sodium terephthalate sulfonate solution and the poly-3-methyl-2-methyl-enacrylamide-ammonium chloride solution are both 0.1~0.5M.

3. The method for preparing a saltwater evaporation power generation hydrogel according to claim 2, characterized in that, The preparation method of the sodium p-styrene sulfonate is as follows: sodium p-styrene sulfonate and α-ketoglutaric acid are mixed and irradiated under ultraviolet light to obtain mixed solution A; mixed solution A is poured into anhydrous ethanol to precipitate, precipitate A is obtained, and precipitate A is dried to obtain sodium p-styrene sulfonate. The preparation method of the poly(3-methyl-2-methylenacrylamide-ammonium chloride) is as follows: 3-methyl-2-methylenacrylamide-ammonium chloride and α-ketoglutaric acid are mixed and irradiated under ultraviolet light to obtain mixed solution B; mixed solution B is poured into anhydrous ethanol to precipitate, and precipitate B is obtained by drying precipitate B to obtain the poly(3-methyl-2-methylenacrylamide-ammonium chloride).

4. The method for preparing a saltwater evaporation power generation hydrogel according to claim 3, characterized in that, The ultraviolet light is characterized by 365nm and 7.5mW / cm². 2 The irradiation time is 8-10 h; the molar percentage of α-ketoglutaric acid and sodium p-styrenesulfonate is 0.1 mol%; the molar percentage of α-ketoglutaric acid and 3-methyl-2-methyl-enacrylamido-ammonium chloride is 0.1 mol%; the drying temperature is 80-100 °C, and the drying time is 12-24 h.

5. The method for preparing a saltwater evaporation hydrogel for power generation according to claim 1, characterized in that, In S2, the volume ratio of the sodium poly(p-styrene sulfonate) solution to the mixed solution is (100~110):

250.

6. The method for preparing a saltwater evaporation hydrogel for power generation according to claim 1, characterized in that, In S3, the volume ratio of the sodium poly(p-styrene sulfonate) solution to the ammonium persulfate aqueous solution is (100~110):250; the concentration of the ammonium persulfate aqueous solution is 0.125M.

7. A salt water evaporation power generation hydrogel, characterized in that, The hydrogel for power generation by salt water evaporation is prepared using any one of claims 1 to 6.

8. The application of the brine evaporation power generation hydrogel according to claim 7, characterized in that, The saltwater evaporation power generation hydrogel is used as an additive in the seawater evaporation power generation process.

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