Replaceable photo-thermal membrane distillation hiking backpack and use method thereof

Abstract

The invention discloses a replaceable photo-thermal membrane distillation hiking backpack and a using method thereof, and relates to the technical field of sea water desalines.The backpack comprises a storage bin, a backpack assembly, a water conveying assembly, a replaceable vacuum water purification unit and a water purification bin, the storage bin and the water purification bin are distributed front and back, and the storage bin and the water purification bin have the storage function and the fresh water storage function; the vacuum water purification unit is formed by stacking a first EVA (Ethylene Vinyl Acetate) plate, a modified birch chip evaporation layer, a hydrophobic layer, a condensation layer and the like, water supply is stable through capillary action, solar energy is used for driving water to evaporate and condense to prepare fresh water, condensation latent heat realizes multi-stage utilization of energy, purified water is treated by an activated carbon sterilization module and then reaches the standard for drinking, and redundant wastewater is collected in a centralized manner. According to the invention, fresh water preparation and outdoor backpack integration is realized, the portability is high, the water production efficiency is high, the water purification scale can be flexibly adjusted, the device adapts to coastal hiking, emergency rescue and other scenes, the problem of outdoor fresh water supply is solved, hiking load is reduced, and the activity range is expanded.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of seawater desalination, in particular to a replaceable photothermal film distillation backpack and a use method thereof. BACKGROUND

[0002] Global freshwater resource shortage has become one of the key challenges restricting human sustainable development. About 71% of the earth's surface is covered by water, but more than 97% of it is seawater, and most of the freshwater resources exist in the form of glaciers, frozen soil, etc., which are difficult to directly use. With the acceleration of industrialization, population growth and the impact of climate change, the contradiction between supply and demand of freshwater resources is becoming increasingly prominent, especially in special scenarios such as outdoor exploration, coastal hiking, island operation, etc., the difficulty of freshwater supply has become a core problem that threatens personnel safety and limits the range of activities.

[0003] In outdoor hiking, field investigation and other activities, the traditional solution relies on carrying sufficient drinking water or relying on fixed supply points, but this not only greatly increases the load of hikers and consumes physical strength, but also severely limits the activity duration and route expansion; when encountering emergency situations such as getting lost, being stranded on an island or natural disasters, the interruption of freshwater supply can directly endanger life safety. Therefore, developing portable, efficient and low-cost outdoor freshwater preparation technology has become a key requirement to solve the water resource dilemma in outdoor scenarios.

[0004] Solar-driven membrane distillation seawater desalination technology has become a research hotspot in the field of freshwater resource preparation due to its advantages of being clean and pollution-free, and having a wide energy source. This technology converts solar energy into heat energy through photothermal materials, precisely acts on the gas-liquid interface to drive water evaporation, and then prepares freshwater through condensation. The core advantage is low energy consumption and strong adaptability. However, the existing solar membrane distillation device still has many defects and cannot meet the needs of outdoor portable use: first, the traditional device is mostly fixed structure, large in size and heavy in weight, lacks integrated design with outdoor equipment, and has poor portability; second, the design of photothermal conversion and condensation system is unreasonable, mostly focusing on the optimization of photothermal materials, ignoring the synergistic efficiency of evaporation-condensation, resulting in low water production rate, and the latent heat released by steam condensation is not effectively utilized, causing serious energy waste; third, the device is easy to be blocked by salt crystallization, and the existing technology lacks a convenient maintenance and replacement mechanism, so the long-term use stability is poor; fourth, the water supply system mostly relies on complex pumps or hydrophilic porous materials, which has complex manufacturing process, high cost, and is difficult to adapt to stable water supply in outdoor bumpy environment; fifth, the existing device has single function and can only realize freshwater preparation, cannot combine with the core needs of outdoor equipment such as storage and carrying, and the practicality is limited.

[0005] In view of the special needs of outdoor hiking, emergency rescue and the like, there is an urgent need for a portable, efficient, maintainable and multifunctional fresh water preparation device. The device needs to solve the problems of large size, low water production efficiency, inconvenient maintenance and single function in the traditional technology, realize the integration of fresh water preparation and outdoor backpack, and have the ability to flexibly adjust the water production scale, conveniently replace the vulnerable parts and adapt to complex outdoor environments, so as to reduce the load of hikers, expand the range of outdoor activities and ensure the safety of drinking water in emergency scenarios, and fill the gap in the field of portable photothermal film distillation fresh water preparation in the prior art. SUMMARY

[0006] This section is intended to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification of the present application in order to avoid obscuring the purpose of this section, the abstract and the title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0007] Therefore, the purpose of the present application is to provide a replaceable photothermal film distillation hiking backpack and a method for using the same to solve the problems raised in the background art.

[0008] To solve the above technical problems, according to one aspect of the present application, the present application provides the following technical solutions: A replaceable photothermal film distillation hiking backpack, comprising: a storage compartment; a carrying assembly connected to the storage compartment for carrying the overall structure; a water delivery assembly installed on both sides of the storage compartment for delivering the water source to be treated to the vacuum water purification unit and collecting the wastewater treated by the vacuum water purification unit; a vacuum water purification unit detachably installed on the storage compartment and detachably connected to the water delivery assembly, which realizes fresh water preparation by photothermal conversion to drive water evaporation-condensation; a water purification compartment detachably installed on the storage compartment and connected to the vacuum water purification unit for collecting and storing the fresh water condensed by the vacuum water purification unit.

[0009] As a preferred scheme of the replaceable photothermal film distillation hiking backpack, the carrying assembly comprises an S-shaped adjustable shoulder strap, a force relieving waist belt and a pressure relieving back pad, and the easy-wearing parts of the adjustable shoulder strap are made of woven nylon material.

[0010] As a preferred scheme of the replaceable photothermal film distillation hiking backpack, the water delivery assembly comprises a water inlet compartment and a wastewater compartment, the water inlet compartment is provided with a first pipeline, and the wastewater compartment is provided with a second pipeline.

[0011] As a preferred scheme of the replaceable photothermal film distillation backpack, the vacuum water purification unit comprises, from top to bottom, a first EVA plate, an evaporation layer, a first water diffusion layer, a hydrophobic layer, a condensation layer, a second water diffusion layer, and a second EVA plate. The first water diffusion layer has water absorption strips penetrating into the first pipeline and extending into the water inlet bin, and has wastewater drainage strips penetrating into the second pipeline and extending into the wastewater bin. The third pipeline is arranged on the water purification bin, and the second water diffusion layer has water purification drainage strips penetrating into the third pipeline and extending into the water purification bin.

[0012] As a preferred scheme of the replaceable photothermal film distillation backpack, the first EVA plate and the second EVA plate are high-transmittance ethylene-vinyl acetate copolymer plastic sheets, the evaporation layer is a chemically modified degradable wood, the hydrophobic layer is a PTFE microporous composite filter membrane, and the condensation layer is made of a degradable material with good thermal conductivity and coated with a hydrophilic coating on the surface.

[0013] As a preferred scheme of the replaceable photothermal film distillation backpack, the degradable wood is a degradable birch wood piece material, which has a vertical vascular bundle structure inside, and the diameter of the vertical vascular bundle structure is 1 mm, accounting for 40-60% of the total pore volume.

[0014] As a preferred scheme of the replaceable photothermal film distillation backpack, the evaporation layer is provided with a micro-nano porous structure on the surface, and the micro-nano porous structure is honeycomb-shaped or biomimetic snake skin texture.

[0015] As a preferred scheme of the replaceable photothermal film distillation backpack, the storage bin and the water purification bin are connected by a strap, and a magic tape is used as an auxiliary fixing structure, the storage bin is used for storing articles, and the water purification bin and the storage bin are distributed along the front-back direction of the backpack.

[0016] As a preferred scheme of the replaceable photothermal film distillation backpack, the bottom of the water purification bin is provided with an activated carbon sterilization module, the side wall is provided with a water outlet and a corresponding valve, and the valve controls the water outlet of the water purification bin.

[0017] A use method of the replaceable photothermal film distillation backpack, comprising the following steps: S1, the vacuum water purification unit is installed in the storage compartment in a detachable manner, the water absorption strip of the first water diffusion layer is inserted into the first pipeline to communicate with the water inlet compartment, the waste water drainage strip is inserted into the second pipeline to communicate with the waste water compartment, and the purified water drainage strip of the second water diffusion layer is inserted into the third pipeline to communicate with the purified water compartment, and the storage compartment and the purified water compartment are fixed by the binding belt and the magic tape; S2, inject the water to be treated into the water inlet compartment, the water absorption strip absorbs the water to be treated through capillary action, uniformly diffuses to the evaporation layer through the first water diffusion layer, and keeps the evaporation layer in a wet state; S3, the backpack is worn on the human body through the bearing assembly, the first EVA plate faces the sun, the solar energy transmits through the high-transmittance first EVA plate to irradiate the evaporation layer, the evaporation layer made of chemically modified degradable wood absorbs light energy and converts it into heat energy, and heats the water to be treated on its surface to evaporate to form water vapor; S4, the water vapor penetrates the hydrophobic layer under the action of pressure difference, condenses into liquid fresh water after contacting the condensation layer coated with a hydrophilic coating, and the liquid fresh water is collected to the purified water drainage strip through the second water diffusion layer; S5, the liquid fresh water is transmitted to the purified water compartment through the purified water drainage strip, sterilized by the activated carbon sterilization module at the bottom of the purified water compartment, and stored; S6, the excess water in the evaporation layer that does not participate in evaporation is guided to the waste water drainage strip through the first water diffusion layer and discharged into the waste water compartment through the second pipeline; S7, when the fresh water is needed, open the valve on the side wall of the purified water compartment, and the sterilized fresh water can be taken out through the water outlet.

[0018] Compared with the prior art, the present application has the beneficial effects that: 1, the fresh water preparation function is deeply integrated with the outdoor backpack, the front and rear distribution design of the storage compartment and the purified water compartment ensures the preparation of fresh water, and the core storage function of the backpack is retained, which completely eliminates the disadvantages of single function and additional weight of traditional outdoor fresh water devices. The bearing assembly composed of S-shaped adjustable shoulder straps, load-releasing waistbands and pressure-relieving back pads, and the wear-resistant woven nylon material used in the easy-to-wear parts of the shoulder straps, not only ensures the comfort and durability of the bearing, but also enables the hiker to carry the water purification equipment without additional burden, significantly reduces the weight and saves the physical strength, effectively expands the hiking routes and activity duration in areas with insufficient fresh water resources such as coastal areas and islands.

[0019] 2, the vacuum water purification unit is detachably connected with the water conveying assembly and the purified water compartment through the pipeline, when the hydrophobic layer appears salt deposition or the components are aged after long-term use, it can be quickly disassembled and replaced, avoiding the problem of reduced water production efficiency caused by blockage of traditional devices, and significantly improving the long-term operation stability of the equipment. At the same time, users can increase or decrease the number of vacuum water purification units according to the actual needs of outdoor duration, number of people, etc., flexibly adjust the water production scale, and adapt to various scenes such as daily hiking and emergency rescue.

[0020] 3、The vacuum water purification unit adopts a stacked structure of a first EVA plate, an evaporation layer, a hydrophobic layer and a condensation layer. The first EVA plate with high light transmittance can maximize the collection of solar energy. The degradable birch sheet evaporation layer is chemically modified. The vertical vascular bundle structure with a diameter of 1 mm inside and the micro-nano porous structure with a honeycomb / bionic snake skin texture on the surface not only strengthen the light capture and light-heat conversion efficiency, but also realize the rapid and uniform transmission of water body through capillary action. The hydrophilic coating coated on the surface of the condensation layer accelerates the condensation of steam, and cooperates with the flow guiding effect of the first and second water diffusion layers to realize the efficient cooperation of evaporation and condensation. In addition, the latent heat released by the steam condensation can help to raise the ambient temperature, indirectly promote the subsequent evaporation process, realize multi-stage utilization of energy, and solve the problems of energy waste and low water production rate of traditional devices.

[0021] 4、The water absorption strip of the first water diffusion layer continuously absorbs the water to be treated from the water inlet by capillary force, without the need for a complex pump body structure, so as to realize stable water supply in an outdoor bumpy environment. At the same time, the waste water drainage strip can guide the excess water in the evaporation layer that does not participate in evaporation into the waste water tank in real time, which not only avoids the increase of thermal resistance caused by water accumulation, but also collects high-salinity waste water to prevent environmental pollution and ensure the continuous and stable operation of the device. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the present application will be described in detail below in combination with the drawings and detailed embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor. Among them: Figure 1 It is a structure schematic diagram of the first perspective view of the replaceable photothermal film membrane distillation backpack of the present application; Figure 2 It is a structure schematic diagram of the second perspective view of the replaceable photothermal film membrane distillation backpack of the present application; Figure 3 It is a structure schematic diagram of the vacuum water purification unit of the replaceable photothermal film membrane distillation backpack of the present application; Figure 4 It is an exploded structure schematic diagram of the vacuum water purification unit of the replaceable photothermal film membrane distillation backpack of the present application; Figure 5 It is a structure schematic diagram of the water purification tank of the replaceable photothermal film membrane distillation backpack of the present application; Figure 6 It is a birch sheet morphology feature diagram provided by the embodiment of the present application; Figure 7 It is a pure water evaporation rate curve diagram provided by the embodiment of the present application; Figure 8An outdoor evaporation rate curve provided for an embodiment of the present invention. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Figures 1-5 The diagram shown is a structural schematic of a replaceable photothermal film distillation hiking backpack according to the present invention. Please refer to [link / reference]. Figures 1-5 The replaceable photothermal film distillation hiking backpack of this embodiment includes a storage compartment 100, a carrying component 200, a water supply component 300, a vacuum water purification unit 400, and a water purification tank 500.

[0025] Storage compartment 100 serves as the core load-bearing and storage unit of the replaceable photothermal film distillation hiking backpack, balancing structural support and storage practicality. It is a key component for achieving integrated functions of freshwater preparation and outdoor storage.

[0026] The carrying component 200 is connected to the storage compartment 100 and is used to support the overall structure. In this embodiment, the carrying component 200 includes an S-shaped adjustable shoulder strap, a pressure-relieving waist belt, and a pressure-relieving back pad. The S-shaped adjustable shoulder strap comfortably fits the waist curve. The whole is made of thickened sponge and breathable mesh. The easily worn parts are made of woven nylon. The pressure-relieving waist belt is equipped with an H-shaped adjustable snap button to effectively distribute pressure and provide comfort and stability.

[0027] Water delivery components 300 are installed on both sides of storage compartment 100 for delivering water to be treated into vacuum water purification unit 400 and collecting wastewater treated by vacuum water purification unit 400. In this embodiment, water delivery components 300 include water inlet compartment 310 and wastewater compartment 320. A first pipe 310a is provided on water inlet compartment 310 and a second pipe is provided on wastewater compartment 320. The first pipe 310a is used to protect water suction strip 430a and the second pipe is used to protect wastewater discharge strip 430b.

[0028] The vacuum water purification unit 400 is detachably installed on the storage chamber 100 and detachably connected to the water supply assembly 300. It achieves freshwater production through photothermal conversion-driven evaporation and condensation of water. In this embodiment, the vacuum water purification unit 400 includes, from top to bottom, a first EVA plate 410, an evaporation layer 420, a first water diffusion layer 430, a hydrophobic layer 440, a condensation layer 450, a second water diffusion layer 460, and a second EVA plate 470, stacked sequentially. The first water diffusion layer 430 has an absorbent strip 430a that penetrates into the first pipe 310a and extends into the water inlet chamber 310, and a condensation layer 450 that penetrates into the second... The pipe extends into the wastewater tank 320 via a wastewater drain strip 430b. A third pipe 510 is installed on the clean water tank 500. The second water diffusion layer 460 has a clean water drain strip 510a that penetrates the third pipe 510 and extends into the clean water tank 500. The first EVA board 410 and the second EVA board 470 are high-transmittance ethylene-vinyl acetate copolymer plastic sheets with a transmittance of over 92%, exhibiting good heat insulation and stability. The evaporation layer 420 is made of chemically modified biodegradable wood, specifically biodegradable birch chips, which, due to their natural hierarchical porous and anisotropic structure, possesses good... It exhibits excellent hydrophilicity and salt resistance, with a surface constructed with a micro-nano porous structure, such as a honeycomb or biomimetic snakeskin texture. Its internal vertical vascular bundle structure enhances light capture and water transport capabilities, ensuring a continuous flow of water to the evaporation interface for efficient localized evaporation. A vacuum insulation layer or multi-layer reflective membrane further reduces overall system heat loss. The hydrophobic layer 440 is a PTFE microporous composite filter membrane with a thickness of 0.16 mm and a pore size of 1 μm, possessing high current carrying capacity, high temperature resistance, and acid and alkali resistance. The condensation layer 450 is made of a biodegradable material with good thermal conductivity and a hydrophilic coating. The absorbent strip 43... 0a An integrated capillary absorbent core, such as paper towel or nylon fiber, continuously supplies water to be treated through the siphon effect, ensuring that the surface of 420 remains moist. At the same time, the wastewater drain strip 430b continuously regulates excess water during the evaporation process to prevent excessive thermal resistance, which would affect the continuous evaporation process and reduce evaporation efficiency. Water vapor rises and condenses into liquid water after encountering the condensation layer 450. It then flows along the condensation layer 450 into the clean water tank 500 below, completing the first stage of condensation. The latent heat released drives the next stage of evaporation, realizing multi-stage condensation and improving water production efficiency. The condensate from each stage is collected in the clean water tank 500 through the guide pipe, completing the collection and storage of fresh water.

[0029] In addition, such as Figure 6 As shown, the surface morphology of the evaporation layer based on biodegradable wood was obtained using field emission scanning electron microscopy. Characterization results show that the evaporation layer used in this design has a rich internal vertical vascular bundle structure with a diameter of approximately 1 mm, accounting for 40-60% of the total pore volume. This promotes effective liquid wetting, achieves rapid water transport through capillary action, and effectively reduces heat loss to the water body. The irregularity of its surface microstructure increases diffuse light reflection.

[0030] The water purification tank 500 is detachably installed on the storage compartment 100 and connected to the vacuum water purification unit 400. It is used to collect and store the fresh water condensed by the vacuum water purification unit 400. In this embodiment, the bottom of the water purification tank 500 is provided with an activated carbon sterilization module, and the side wall of the 500 is provided with a water outlet and a corresponding valve 520. The valve 520 controls the water outlet of the water purification tank 500. The storage compartment 100 is connected to the water purification tank 500 by a strap and uses Velcro as an auxiliary fixing structure. The storage compartment 100 is used to store items. The water purification tank 500 and the storage compartment 100 are distributed along the front and back direction of the backpack.

[0031] Combination Figures 1-5 The replaceable photothermal film distillation hiking backpack of this embodiment is used as follows: S1. The vacuum water purification unit 400 is detachably installed in the storage compartment 100, and the water absorption strip 430a of the first water diffusion layer 430 is inserted into the first pipe 310a and connected to the water inlet 310. The wastewater drainage strip 430b is inserted into the second pipe and connected to the wastewater compartment 320. At the same time, the clean water drainage strip 510a of the second water diffusion layer 460 is inserted into the third pipe 510 and connected to the clean water compartment 500. The storage compartment 100 and the clean water compartment 500 are fixed by straps and Velcro. S2. Inject the water to be treated into the water inlet 310. The water absorption strip 430a adsorbs the water to be treated through capillary action and diffuses it evenly to the evaporation layer 420 through the first water diffusion layer 430, so that the evaporation layer 420 is kept moist. S3. Wear the backpack on the body through the carrying component 200, so that the first EVA board 410 faces the sun. Solar energy shines through the highly transparent first EVA board 410 to the evaporation layer 420. The evaporation layer 420, made of chemically modified biodegradable wood, absorbs light energy and converts it into heat energy, heating the water to be treated on its surface and causing it to evaporate into water vapor. S4. Water vapor penetrates the hydrophobic layer 440 under the action of pressure difference, and condenses into liquid fresh water after contacting the condensation layer 450 with the surface coated with a hydrophilic coating. The liquid fresh water is collected into the clean water drainage strip 510a through the second water diffusion layer 460. S5. Liquid fresh water is transferred to the water purification tank 500 through the water purification drain strip 510a, and then stored after being sterilized by the activated carbon sterilization module at the bottom of the water purification tank 500. S6. Excess water in the evaporation layer 420 that does not participate in evaporation is guided to the wastewater drainage strip 430b through the first water diffusion layer 430 and discharged into the wastewater tank 320 for collection through the second pipe. S7. When you need fresh water, open valve 520 on the side wall of the water purification chamber 500 and take out the sterilized fresh water through the outlet.

[0032] To verify the water treatment effect of the vacuum water purification unit 400 of the present invention, experimental verification was conducted, such as... Figure 7 and Figure 8 As shown, experimental results indicate that the evaporation rate decreases slightly with increasing brine concentration, but remains consistently high, exceeding 4 kg·m⁻²·h⁻¹. Furthermore, the vacuum water purification unit 400 designed in this invention exhibits extremely high energy utilization efficiency, exceeding 200%. This result not only demonstrates the stable performance of the evaporator in a high-salt environment but also further verifies its application potential in efficient seawater desalination.

[0033] In summary, this invention solves the aforementioned problems through a specific salt crystallization process in a designated area. Salt crystallizes at the end of the nonwoven fabric and naturally detaches under gravity, achieving efficient salt collection. The invention connects the evaporation zone to the surrounding water body through 1mm diameter pores, utilizing atmospheric pressure to provide a stable water supply and ensure the moisture content of the nonwoven fabric in the evaporation groove. Simultaneously, the pore size can be adjusted according to actual conditions to balance water supply and heat loss. All components of this invention use inexpensive and readily available materials, and the assembly process is simple, demonstrating significant potential for industrial application. Finally, the invention's ingenious opening design creates a good airflow path driven by temperature differences. This design can promptly remove the wet vapor generated in the evaporation zone, thereby further enhancing the evaporation process. This design not only improves evaporation efficiency but also optimizes the overall system performance.

[0034] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A replaceable photothermal membrane distillation backpack, characterized in that, The utility model relates to a portable water purification device, comprising: a storage bin (100); a backpacking assembly (200) connected with the storage bin (100) and used for carrying the whole structure; a water conveying assembly (300) installed on both sides of the storage bin (100) and used for conveying water to be treated into a vacuum water purification unit (400) and collecting wastewater treated by the vacuum water purification unit (400); the vacuum water purification unit (400) is detachably installed on the storage bin (100) and detachably connected with the water conveying assembly (300), and fresh water is prepared by driving water evaporation-condensation through light-heat conversion; a water purification bin (500) detachably installed on the storage bin (100) and connected with the vacuum water purification unit (400) and used for collecting and storing the fresh water condensed by the vacuum water purification unit (400).

2. A replaceable photothermal membrane distillation backpack according to claim 1, wherein, The backpacking assembly (200) comprises an S-shaped adjustable shoulder strap, a force relieving waistband and a pressure relieving back pad, and the easy-wearing part of the adjustable shoulder strap is made of woven nylon.

3. A replaceable photothermal membrane distillation backpack according to claim 1, wherein, The water conveying assembly (300) comprises a water inlet bin (310) and a wastewater bin (320), the water inlet bin (310) is provided with a first pipeline (310a), and the wastewater bin (320) is provided with a second pipeline.

4. A replaceable photothermal membrane distillation backpack according to claim 3, wherein, The vacuum water purification unit (400) comprises, from top to bottom, a first EVA plate (410), an evaporation layer (420), a first water diffusion layer (430), a hydrophobic layer (440), a condensation layer (450), a second water diffusion layer (460) and a second EVA plate (470); The first water diffusion layer (430) has water absorption strips (430a) penetrating into the first pipeline (310a) and extending into the water inlet bin (310) and wastewater drainage strips (430b) penetrating into the second pipeline and extending into the wastewater bin (320); The water purification bin (500) is provided with a third pipeline (510), and the second water diffusion layer (460) has clean water drainage strips (510a) penetrating into the third pipeline (510) and extending into the water purification bin (500).

5. A replaceable photothermal membrane distillation backpack according to claim 4, wherein, The first EVA plate (410) and the second EVA plate (470) are high-transmittance ethylene-vinyl acetate copolymer plastic sheets, the evaporation layer (420) is a degradable wood treated by chemical modification, the hydrophobic layer (440) is a PTFE microporous composite filter membrane, and the condensation layer (450) is made of a degradable material with good thermal conductivity and is coated with a hydrophilic coating on the surface.

6. A replaceable photothermal membrane distillation backpack according to claim 5, wherein, The degradable wood is a degradable birch wood piece material, which has a vertical vascular bundle structure inside, the diameter of the vertical vascular bundle structure is 1 mm, and the vertical vascular bundle structure accounts for 40-60% of the total pore volume.

7. A replaceable photothermal membrane distillation backpack according to claim 4, wherein, The evaporation layer (420) is provided with a micro-nano porous structure on the surface, and the micro-nano porous structure is honeycomb-shaped or biomimetic snake skin texture.

8. A replaceable photothermal membrane distillation backpack according to claim 1, wherein, The storage bin (100) and the water purification bin (500) are connected through a belt and are secondarily fixed by a magic tape, the storage bin (100) is used for storing articles, and the water purification bin (500) and the storage bin (100) are distributed along the front-rear direction of the backpack.

9. A replaceable photothermal membrane distillation backpack according to claim 1, wherein, The bottom of the water purification bin (500) is provided with an activated carbon sterilization module, and the sidewall of the water purification bin (500) is provided with a water outlet and a corresponding valve (520), and the valve (520) controls the water outlet of the water purification bin (500).

10. A method of using a replaceable photothermal film distillation backpack according to any one of claims 1-9, wherein, The steps are as follows: S1, the vacuum water purification unit (400) is detachably installed in the storage bin (100), and the water absorption strip (430a) of the first water diffusion layer (430) penetrates into the first pipeline (310a) and communicates with the water inlet bin (310), the waste water drainage strip (430b) penetrates into the second pipeline and communicates with the waste water bin (320), and at the same time, the purified water drainage strip (510a) of the second water diffusion layer (460) penetrates into the third pipeline (510) and communicates with the water purification bin (500), and the storage bin (100) and the water purification bin (500) are fixed by the binding belt and the magic tape; S2, inject the water to be treated into the water inlet bin (310), the water absorption strip (430a) absorbs the water to be treated by capillary action, uniformly diffuses to the evaporation layer (420) through the first water diffusion layer (430), and keeps the evaporation layer (420) in a wet state; S3, the backpack is worn on the human body through the carrying assembly (200), the first EVA plate (410) faces the sun, the solar energy penetrates through the high-transmittance first EVA plate (410) and irradiates to the evaporation layer (420), the evaporation layer (420) made of chemically modified degradable wood absorbs light energy and converts it into heat energy, and heats the water to be treated on its surface to evaporate and form water vapor; S4, the water vapor penetrates the hydrophobic layer (440) under the action of pressure difference, and condenses into liquid fresh water after contacting the condensation layer (450) coated with a hydrophilic coating, and the liquid fresh water is collected to the purified water drainage strip (510a) through the second water diffusion layer (460); S5, the liquid fresh water is transmitted to the water purification bin (500) through the purified water drainage strip (510a), and is stored after sterilization treatment by the activated carbon sterilization module at the bottom of the water purification bin (500); S6, the excess water in the evaporation layer (420) not involved in evaporation is guided to the waste water drainage strip (430b) through the first water diffusion layer (430), and is discharged into the waste water bin (320) through the second pipeline for collection; S7, when the fresh water is needed, open the valve (520) on the sidewall of the water purification bin (500), and take out the sterilized fresh water through the water outlet.

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