A degradable and recyclable solar seawater desalination evaporator and preparation method thereof

Abstract

The present invention relates to the technical field of seawater desalination, and in particular to a degradable and recyclable solar seawater desalination evaporator and a preparation method thereof. The degradable and recyclable solar seawater desalination evaporator of the present invention comprises a water supply layer and an evaporation layer; the water supply layer is a carrageenan hydrogel; and the evaporation layer is a ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel. The degradable and recyclable solar seawater desalination evaporator of the present invention can efficiently evaporate seawater into water vapor under the irradiation of sunlight, thereby increasing the output of fresh water. It has high photothermal conversion efficiency and can make full use of solar energy resources. The evaporator also has the advantages of degradable recycling and magnetic recovery, which reduces costs and environmental impacts.

Description

Technical Field

[0001] The invention relates to the technical field of seawater desalination, and in particular to a degradable and recyclable solar seawater desalination evaporator and a preparation method thereof. Background Art

[0002] As an effective solution, seawater desalination can transform abundant seawater resources into fresh water for human use, which has important practical significance. Solar desalination technology uses solar energy, a clean and renewable energy source, to evaporate and condense seawater into fresh water through photothermal conversion, reducing dependence on fossil energy. However, existing solar desalination technology still has some shortcomings in material selection and system design, which limits its widespread application.

[0003] As an important means of solar desalination, interfacial desalination technology improves the efficiency of seawater evaporation by constructing an efficient light-heat conversion interface on the surface of the evaporator. However, existing interfacial desalination technologies mostly use non-degradable materials such as polyacrylamide as evaporators. These materials will pollute the environment after being discarded, and most of them are non-recyclable, further exacerbating resource waste and environmental burden. Therefore, it is of great significance to develop an innovative green solar desalination technology to overcome the limitations of existing technologies and achieve biodegradability and recycling of evaporators. Summary of the invention

[0004] Based on the above content, the present invention provides a degradable and recyclable solar seawater desalination evaporator and a preparation method thereof.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is a degradable and recyclable solar desalination evaporator (abbreviated as: evaporator), comprising a water supply layer and an evaporation layer;

[0007] The water supply layer is carrageenan hydrogel; the evaporation layer is ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel.

[0008] The second technical solution of the present invention is a method for preparing the above-mentioned degradable and recyclable solar desalination evaporator, which uses the carrageenan aqueous solution as an adhesive to adhere the evaporation layer to the surface of the water supply layer, and allows it to stand to obtain the degradable and recyclable solar desalination evaporator.

[0009] The third technical solution of the present invention is the application of the above-mentioned degradable and recyclable solar seawater desalination evaporator in seawater desalination.

[0010] A fourth technical solution of the present invention is a solar seawater desalination device, comprising a platform, a degradable and recyclable solar seawater desalination evaporator arranged on the platform, and a transparent glass cover.

[0011] The present invention discloses the following technical effects:

[0012] (1) Efficient evaporation: The degradable and recyclable solar desalination evaporator of the present invention can efficiently evaporate seawater into water vapor under the irradiation of sunlight, thereby increasing the production of fresh water. It has a high photothermal conversion efficiency (as reflected in the evaporation rate) and can make full use of solar energy resources.

[0013] (2) Degradable and recyclable: Carrageenan has good biodegradability. After aging for one year of continuous use, it can be completely biodegraded by adding carrageenan degrading enzymes, reducing environmental pollution.

[0014] (3) Magnetic recovery: As photothermal materials, ferroferric oxide and yttrium iron garnet ferrite are magnetic. Using magnets, ferroferric oxide and yttrium iron garnet ferrite can be easily recovered, realizing multiple recycling and reuse of the photothermal layer, further reducing costs and environmental impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 This is a schematic diagram of the degradable and recyclable solar seawater desalination evaporator of the present invention.

[0017] Figure 2 It is a schematic diagram of the solar seawater desalination device of the present invention. DETAILED DESCRIPTION

[0018] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0019] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0020] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0021] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0022] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0023] The "room temperature" described in the present invention, unless otherwise specified, refers to 20-30°C.

[0024] A first aspect of the present invention provides a degradable and recyclable solar seawater desalination evaporator, comprising a water supply layer and an evaporation layer;

[0025] The water supply layer is carrageenan hydrogel; the evaporation layer is ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel.

[0026] The evaporator can be heated to 70°C-100°C to dissolve the evaporator, and the dissolved carrageenan solution can be completely biodegraded by carrageenan degrading enzymes. The ferroferric oxide and yttrium iron garnet ferrite in the evaporation layer can be recycled and reused using magnets after the carrageenan is biodegraded by the carrageenan degrading enzymes. The types of magnets are permanent magnets and soft magnets, and their types include but are not limited to samarium cobalt, neodymium iron boron, ferrite, aluminum nickel cobalt, iron chromium cobalt, etc.

[0027] The water supply layer of the evaporator has a diameter of 60-100 mm and a height of 2-6 mm, and the evaporation layer has a diameter of 60-100 mm and a height of 0.2-0.8 mm.

[0028] Under the irradiation of sunlight, the evaporator can evaporate the water in the seawater into water vapor, which condenses into fresh water, thus realizing seawater desalination.

[0029] After one year of continuous use, the evaporator will be discarded due to aging. Enzyme treatment can make the carrageenan of the evaporator 100% biodegradable, and ferroferric oxide and yttrium iron garnet ferrite can be recycled and reused by magnet absorption. The advantage of the evaporator of the present invention is that the evaporator can continuously desalinate seawater. When the evaporator is aged and discarded, it is biodegraded and magnetically recovered to avoid pollution to the environment, providing a new solution with application prospects in the field of environmentally friendly and low-cost solar desalination technology.

[0030] In a preferred embodiment of the present invention, the method for preparing the carrageenan hydrogel comprises the following steps:

[0031] Carrageenan and potassium chloride are mixed and dissolved in water to obtain a carrageenan aqueous solution, which is then cross-linked at room temperature to obtain the carrageenan hydrogel.

[0032] In a preferred embodiment of the present invention, the dissolving method is: first stirring in a 95° C. magnetic water bath for 60 minutes until the liquid is transparent; stopping stirring and continuing heating until the liquid is clear without bubbles, thereby obtaining a carrageenan aqueous solution.

[0033] In a preferred embodiment of the present invention, the cross-linking time is 3 hours.

[0034] In a preferred embodiment of the present invention, the mass ratio of carrageenan to potassium chloride is (1-3.5): (0.01-0.08); and the mass concentration of carrageenan in the carrageenan aqueous solution is 1%-3.5%.

[0035] In the present invention, potassium chloride is a cross-linking agent for carrageenan. After carrageenan is cross-linked, its gel strength is improved, ensuring good performance. If the amount of potassium chloride added is too little, the performance cannot be optimized, and if the amount of potassium chloride added is too much, the cost is increased.

[0036] When the mass concentration of carrageenan in the carrageenan aqueous solution is within the above-mentioned range, the prepared water supply layer has better performance; if the concentration is too low, the performance is poor; if the concentration is too high, the cost is increased.

[0037] In a preferred embodiment of the present invention, the method for preparing the ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel comprises the following steps:

[0038] Dissolving carrageenan in water, and adding ferroferric oxide and yttrium iron garnet ferrite to disperse uniformly, to obtain a ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution;

[0039] The ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution is coated on cellulose filter paper to obtain the ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel.

[0040] In a preferred embodiment of the present invention, the mass ratio of the ferroferric oxide, yttrium iron garnet ferrite and carrageenan is (6-12): (0.6-1.2): (0.8-1.2); the pore size of the cellulose filter paper is 2-25 μm; and the mass concentration of carrageenan in the ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution is 0.8%-1.2%.

[0041] The reason why the mass ratio of ferroferric oxide, yttrium iron garnet ferrite and carrageenan is limited to the above-mentioned ratio range when preparing the ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel is: experimental results show that only within the above-mentioned ratio range can the evaporation performance of the prepared evaporation layer be better.

[0042] In a preferred embodiment of the present invention, the temperature at which carrageenan is dissolved in water is 70-100°C.

[0043] The second aspect of the present invention provides a method for preparing the above-mentioned degradable and recyclable solar desalination evaporator, wherein the evaporation layer is adhered to the surface of the water supply layer using the carrageenan aqueous solution as an adhesive and allowed to stand to obtain the degradable and recyclable solar desalination evaporator.

[0044] In a preferred embodiment of the present invention, the standing time is 20 minutes.

[0045] The third aspect of the present invention provides an application of the above-mentioned degradable and recyclable solar seawater desalination evaporator in seawater desalination.

[0046] A fourth aspect of the present invention provides a solar desalination device, comprising a platform, a degradable and recyclable solar desalination evaporator arranged on the platform, and a transparent glass cover.

[0047] The process of desalination of seawater by the solar desalination device is as follows: the evaporator is floated on the seawater, and under the irradiation of sunlight, the evaporator evaporates the seawater through the efficient photothermal conversion effect, and the generated water vapor rises, condenses into fresh water after encountering the transparent glass cover, flows down along the glass cover, and the fresh water is collected. The evaporator can continuously desalinate seawater under the irradiation of sunlight.

[0048] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0049] The schematic diagram of the degradable and recyclable solar desalination evaporator of the present invention is as follows Figure 1 As shown; the upper layer of the evaporator is ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel, which serves as the evaporation layer; the lower layer is carrageenan hydrogel, which serves as the water supply layer.

[0050] The schematic diagram of the solar desalination device of the present invention is as follows Figure 2 As shown, sunlight shines through the transparent glass cover onto the evaporator, evaporating the seawater adsorbed by the hydrogel. The generated water vapor rises, condenses when it encounters the glass cover, flows down along the glass cover, and the condensed fresh water is collected.

[0051] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0052] Example 1

[0053] (1) Preparation of carrageenan hydrogel: Add 1g carrageenan, 0.01g potassium chloride and 98.99g distilled water into a 100ml beaker and stir evenly with a glass rod. Place the mixture in a 95℃ magnetic water bath and stir for 60 minutes until the liquid becomes transparent. Stop stirring and continue heating. When the liquid is clear and free of bubbles, a carrageenan aqueous solution is obtained and poured into a vessel with a diameter of 80 mm. Crosslink and cool at room temperature for 3 hours to obtain a carrageenan hydrogel.

[0054] (2) Preparation of ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution: 6 g ferroferric oxide, 0.6 g yttrium iron garnet ferrite, 0.8 g carrageenan and 92.6 g distilled water were mixed, the temperature was controlled at 95°C in a magnetic stirring water bath, and the mixture was heated and stirred until the carrageenan was completely dissolved. The ferroferric oxide and yttrium iron garnet ferrite were stirred and dispersed evenly to prepare a ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution.

[0055] (3) Preparation of evaporation layer: 0.5 g of the ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixture prepared in step (2) was coated on a cellulose filter paper with a pore size of 20 μm to obtain an evaporation layer with a height of about 0.5 mm.

[0056] (4) FeO / Yttrium iron garnet ferrite / carrageenan composite hydrogel evaporator (abbreviated as: evaporator): The evaporation layer prepared in step (3) is adhered to the surface of the carrageenan hydrogel prepared in step (1) with the carrageenan aqueous solution prepared in step (1) (heated to 95°C), and the mixture is allowed to stand for 20 minutes to obtain a FeO / Yttrium iron garnet ferrite / carrageenan composite hydrogel evaporator. The evaporator has a diameter of 80 mm and a height of 4.5 mm.

[0057] (5) Evaporator degradation and recycling: After one year of continuous use, the evaporator ages. The carrageenan is completely degraded by adding carrageenan-degrading enzyme, and the ferrosoferric oxide and yttrium iron garnet ferrite are recovered and reused by magnets to prepare a new evaporator.

[0058] Example 2

[0059] (1) Preparation of carrageenan hydrogel: same as step (1) of Example 1.

[0060] (2) Preparation of ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution: 6.2 g ferroferric oxide, 0.62 g yttrium iron garnet ferrite, 0.8 g carrageenan and 92.38 g distilled water were mixed, the temperature was controlled at 95°C in a magnetic stirring water bath, and the mixture was heated and stirred until the carrageenan was completely dissolved. The ferroferric oxide and yttrium iron garnet ferrite were stirred and dispersed evenly to prepare a ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution.

[0061] (3) Preparation of evaporation layer: 0.5 g of the ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixture prepared in step (2) was coated on a cellulose filter paper with a pore size of 20 μm to obtain an evaporation layer with a height of about 0.5 mm.

[0062] (4) Fe3O4 / Yttrium Iron Garnet Ferrite / Carrageenan Composite Hydrogel Evaporator: The evaporation layer prepared in step (3) is adhered to the surface of the carrageenan hydrogel prepared in step (1) with the carrageenan aqueous solution prepared in step (1) (heated to 95°C), and the mixture is allowed to stand for 20 minutes to obtain a Fe3O4 / Yttrium Iron Garnet Ferrite / Carrageenan Composite Hydrogel Evaporator. The evaporator has a diameter of 80 mm and a height of 4.5 mm.

[0063] (5) Evaporator degradation and recycling: After the evaporator has been used continuously for one year and aged, the carrageenan is completely degraded by adding carrageenan-degrading enzyme, and the ferrosoferric oxide and yttrium iron garnet ferrite are recovered and reused by magnets to prepare a new evaporator.

[0064] Example 3

[0065] (1) Preparation of carrageenan hydrogel: same as step (1) of Example 1.

[0066] (2) Preparation of ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution: 6.4 g ferroferric oxide, 0.64 g yttrium iron garnet ferrite, 0.8 g carrageenan and 92.16 g distilled water were mixed, the temperature was controlled at 95°C in a magnetic stirring water bath, and the mixture was heated and stirred until the carrageenan was completely dissolved. The ferroferric oxide and yttrium iron garnet ferrite were stirred and dispersed evenly to prepare a ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution.

[0067] (3) Preparation of evaporation layer: 0.5 g of the ferroferric oxide / yttrium iron garnet ferrite / carrageenan solution prepared in step (2) was coated on a cellulose filter paper with a pore size of 20 μm to obtain an evaporation layer with a height of about 0.5 mm.

[0068] (4) FeO / Yttrium iron garnet ferrite / carrageenan composite hydrogel evaporator: The evaporation layer prepared in step (3) is adhered to the surface of the carrageenan hydrogel prepared in step (1) with the carrageenan aqueous solution prepared in step (1) (heated to 95°C), and the mixture is allowed to stand for 20 minutes to obtain a FeO / Yttrium iron garnet ferrite / carrageenan composite hydrogel evaporator. The evaporator has a diameter of 80 mm and a height of 4.5 mm.

[0069] (5) Evaporator degradation and recycling: After the evaporator has been used continuously for one year and aged, the carrageenan is completely degraded by adding carrageenan-degrading enzyme, and the ferrosoferric oxide and yttrium iron garnet ferrite are recovered and reused by magnets to prepare a new evaporator.

[0070] Effect verification 1

[0071] The evaporator prepared in Example 1-3 was used Figure 2 The device was used to conduct solar desalination experiments to measure the evaporation rate and the concentrations of sodium ions, magnesium ions, potassium ions and calcium ions before and after desalination. The results are shown in Tables 1 and 2:

[0072] Table 1 Evaporation rates of three evaporators

[0073] Evaporator Example 1 Example 2 Example 3 average <![CDATA[Evaporation rate (kg·m -2 ·h -1 ).]]> 1.780 1.886 2.103 1.923

[0074] As shown in Table 1, Examples 1-3 all have good evaporation rates, with an average of 1.923 kg·m -2 ·h -1 .

[0075] Table 2 Concentration of metal ions before and after desalination (ppm)

[0076] Example Sodium ion Magnesium ion Potassium Calcium Untreated seawater 11750 7540 536 459 Example 1 (after desalination) 8.34 5.42 1.74 1.46 Example 2 (after desalination) 8.27 5.49 1.69 1.54 Example 3 (after desalination) 8.33 5.35 1.88 1.79

[0077] It can be seen from Table 2 that the removal rate of salt in the water after desalination treatment by the solar seawater desalination device of the present invention reaches 99.9%.

[0078] Comparative Example 1

[0079] The only difference from Example 3 is that in step (2), the addition of ferrosoferric oxide is omitted, and the remaining steps and parameters are the same as those in Example 3.

[0080] Comparative Example 2

[0081] The only difference from Example 3 is that in step (2), the addition of yttrium iron garnet ferrite is omitted, and the remaining steps and parameters are the same as those in Example 3.

[0082] The evaporators prepared in Comparative Examples 1 and 2 were subjected to the same effect verification as in Effect Verification Example 1. The results are shown in Tables 3 and 4.

[0083] Table 3 Evaporation rate of evaporator

[0084] Evaporator Comparative Example 1 Comparative Example 2 <![CDATA[Evaporation rate (kg·m -2 ·h -1 )]]> 1.012 0.717

[0085] Table 4 Concentration of metal ions before and after seawater desalination (ppm)

[0086] Example Sodium ion Magnesium ion Potassium Calcium Untreated seawater 11750 7540 536 459 Comparative Example 1 (after dilution) 8.41 5.39 1.84 1.52 Comparative Example 2 (after dilution) 8.39 5.28 1.69 1.45

[0087] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A degradable and recyclable solar desalination evaporator, characterized in that: Includes water supply layer and evaporation layer; The water supply layer is carrageenan hydrogel; the evaporation layer is ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel; The preparation method of the carrageenan hydrogel comprises the following steps: Mixing carrageenan and potassium chloride and dissolving them in water to obtain a carrageenan aqueous solution, and then cross-linking at room temperature to obtain the carrageenan hydrogel; The mass ratio of carrageenan to potassium chloride is (1-3.5): (0.01-0.08); the mass concentration of carrageenan in the carrageenan aqueous solution is 1%-3.5%; The preparation method of the ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel comprises the following steps: Dissolving carrageenan in water, and adding ferroferric oxide and yttrium iron garnet ferrite to disperse uniformly, to obtain a ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution; The ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution is coated on cellulose filter paper to obtain a ferroferric oxide / yttrium iron garnet ferrite / carrageenan composite hydrogel; The mass ratio of the ferroferric oxide, yttrium iron garnet ferrite and carrageenan is (6-12): (0.6-1.2): (0.8-1.2); the pore size of the cellulose filter paper is 2-25 μm; and the mass concentration of carrageenan in the ferroferric oxide / yttrium iron garnet ferrite / carrageenan mixed solution is 0.8%-1.2%.

2. A method for preparing the degradable and recyclable solar desalination evaporator according to claim 1, characterized in that: The evaporation layer is adhered to the surface of the water supply layer using the carrageenan aqueous solution as an adhesive and allowed to stand to obtain the degradable and recyclable solar seawater desalination evaporator.

3. Application of the degradable and recyclable solar seawater desalination evaporator as claimed in claim 1 in seawater desalination.

4. A solar desalination device, characterized in that: The invention comprises a platform, the degradable and recyclable solar seawater desalination evaporator as claimed in claim 1 and a transparent glass cover which are arranged on the platform.

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