A three-dimensional terry fabric and a method for manufacturing the same and use thereof

Abstract

The present application relates to a kind of stereoscopic terry knitted fabric and its preparation method and application, belong to seawater desalination technical field.The preparation method of the present application includes the following steps: S1, hydrophilic substrate is immersed in chlorate solution, and modified hydrophilic substrate is obtained by drying;S2, the modified hydrophilic substrate of S1 is immersed in surfactant solution for pretreatment, and pretreated hydrophilic substrate is obtained;S3, the pretreated hydrophilic substrate of S1 is immersed in oxidizing agent solution for 10min-30min, then monomer is added for in-situ polymerization, and composite yarn is obtained by drying;S4, the composite yarn of S3 is knitted on support fiber by knitting machine, and composite terry yarn is obtained;S5, the composite terry yarn of S4 is knitted by knitting machine, and stereoscopic terry knitted fabric is obtained.The stereoscopic terry knitted fabric of the present application exhibits its excellent stability, continuity and practicability in high salinity seawater desalination in the interface photothermal water evaporation system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of seawater desalination, and particularly relates to a three-dimensional pile fabric, a preparation method and application thereof. BACKGROUND

[0002] With the increasing pressure of global population growth and environmental pollution, water resource shortage and pollution have become serious problems. Traditional solutions to seawater resources, such as membrane distillation, reverse osmosis, and electrodialysis, have been applied to alleviate the freshwater crisis. However, their huge energy consumption and complex equipment limit their application. In recent years, green, cheap, and efficient interfacial photothermal water evaporation technology has been widely studied in seawater desalination and purification. Seawater is transported to the evaporator interface through the water supply material, and the photothermal conversion material converts clean and free light energy into heat energy for seawater desalination. However, the availability of photothermal water evaporation technology in high-salinity seawater and the stability of seawater desalination over a long period of time are a thorny problem. With the increase of running time, the accumulation of salt on the photothermal material or water transport material will weaken the evaporation rate and pollute the evaporator. Therefore, improving salt rejection and stability has become a core difficulty in photothermal water evaporation systems.

[0003] Currently, traditional seawater desalination technology cannot meet the requirements of modern society due to its complex structure, high energy consumption, and poor portability. Photothermal interfacial water evaporation technology only uses solar energy as a clean energy source to convert light energy into heat energy for seawater evaporation, without the need for additional consumption of non-renewable energy sources such as oil and natural gas. However, most interfacial photothermal water evaporation devices cannot maintain long-term operational stability in high-concentration saltwater, and salt crystals will deposit in the water transport channel or condense on the evaporator, affecting the overall evaporation efficiency of the system. Salt rejection schemes can be divided into externally driven and self-driven. Externally driven salt rejection schemes such as water washing and directional salt discharge require manual salt removal or collection to maintain cleanliness; self-driven salt rejection can ensure the stability and continuity of system operation. Self-driven salt rejection mainly relies on hydrophilic flow diffusion, but in high-salinity seawater desalination, salt horizontal flow diffusion relying on material hydrophilicity is limited, so further optimizing water circulation is a key technology to ensure photothermal water evaporation technology rejection.

[0004] Invention patent CN 114314993 A discloses a method for making a seawater desalination and salt removal equipment based on resource recycling and application. A dam body is set on the coast, and a heating box for seawater desalination and salt removal is set on one side of the dam body. A baffle is set on the side of the dam body facing the seawater. The impact force of the sea waves can intermittently impact the baffle, and the reciprocating movement of the baffle can drive the movement of the shaking mechanism in the heating box, thereby achieving the effect of salt removal. However, this method does not significantly improve the salt removal efficiency, and the system structure is too complex and the cost is too high.

[0005] Invention patent CN 116949808 A discloses a Janus nanofiber membrane and its preparation method and application. First, an ultrahydrophobic polysulfone-based nanofiber membrane is prepared, then an ultrathin photo-thermal conversion layer is prepared, then ultraviolet light cross-linking modification is carried out, and finally a polysulfone-based Janus nanofiber membrane is prepared. Although this photo-thermal absorption membrane layer with hydrophilic / hydrophobic double-layer structure can alleviate the salting-out effect to some extent, its complex manufacturing process, difficulty in efficient mass production and high cost limit its application in industry.

[0006] Invention patent CN 113772771 A discloses a tubular flow salt-free crystallization photo-thermal seawater desalination device and its preparation method. In addition to providing a seawater desalination device, the device can also utilize the liquid surface potential energy to guide the flow of liquid, evaporate through the photo-thermal layer, and be excluded before the liquid evaporates to the saturation concentration, thereby achieving the purpose of eliminating salt crystallization in the photo-thermal conversion layer and the water delivery layer, and enhancing the salt resistance of the device. However, the device has high precision requirements, low evaporation efficiency, and cannot be mass-produced. SUMMARY

[0007] To solve the above technical problems, the present application provides a three-dimensional loop knitted fabric and its preparation method and application. The three-dimensional loop knitted fabric (IBFF) with water-induced (high-concentration seawater hydrophilic horizontal flow-diffusion, air water collection to provide freshwater circulation) self-driven salt dilution function uses hydrophilic substrates such as Tencel as water delivery materials. First, hydrophilic chlorides are attached to the surface of the hydrophilic substrate to enable the composite yarn to capture environmental moisture. Then, a polymer with excellent photo-thermal conversion efficiency is polymerized in situ on the surface to reinforce it. The prepared composite yarn has properties such as photo-thermal conversion, moisture supply, and air water collection. Then, carbon fibers with excellent mechanical properties are used as core layer yarns to provide mechanical support for the entire composite loop yarn, and the composite yarn is wrapped on the outside to achieve water circulation and evaporation.

[0008] The first object of the present application is to provide a preparation method of a three-dimensional loop knitted fabric, comprising the following steps:

[0009] S1, immersing a hydrophilic substrate in a chloride salt solution and drying to obtain a modified hydrophilic substrate; the hydrophilic substrate is selected from one or more of Tencel, cotton, acetate fiber and wool;

[0010] S2, immersing the modified hydrophilic substrate of S1 in a surfactant solution for pretreatment to obtain a pretreated hydrophilic substrate;

[0011] S3, dipping the pretreated hydrophilic substrate in S1 into an oxidant solution for 10-30 min, then adding monomers for in-situ polymerization, and drying to obtain a composite yarn; the monomers are selected from one or more of pyrrole, dopamine and aniline;

[0012] S4, weaving the composite yarn in S3 on supporting fibers by a weaving machine to obtain a composite loop yarn; wherein the supporting fibers are interlaced to form a woven structure, a part of each composite yarn is embedded in the inside of the woven structure under the weaving force of the supporting fibers, and the other part is accumulated on the outer layer of the woven structure to form a loop structure due to stress relaxation; the supporting fibers are selected from one or more of carbon fibers, polyphenylene terephthalamide fibers, graphite fibers and silicon carbide fibers;

[0013] S5, weaving the composite loop yarn in S4 by a weaving machine to obtain a three-dimensional loop woven fabric.

[0014] Preferably, in S1, the hydrophilic substrate is selected from Tencel, which exhibits a compact cluster structure, has abundant fiber cracks and inter-fiber gaps, and can be used for water circulation.

[0015] In an embodiment of the present application, in S1, the chloride salt is selected from one or more of lithium chloride, calcium chloride and potassium chloride, and the hydrophilic chloride salt can capture fog water diluted salt; preferably, lithium chloride; the concentration of the chloride salt solution is 5wt%-10wt%, for example, it can be 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%. The higher the concentration of the chloride salt solution, the better the moisture absorption effect, but when the concentration of the chloride salt solution continues to rise, the moisture absorption effect will reach saturation, and excessive chloride salt load will block the yarn pore size.

[0016] In an embodiment of the present application, in S1, the drying is 60-80℃ drying for 60-90 min.

[0017] In an embodiment of the present application, in S2, the surfactant is selected from sodium dodecyl benzene sulfonate and / or sodium dodecyl sulfate; the concentration of the surfactant solution is 0.05wt%-0.2wt%.

[0018] In an embodiment of the present application, in S3, the oxidant is selected from one or more of ferric chloride, ammonium persulfate, sodium persulfate and potassium persulfate; the concentration of the oxidant solution is 0.12mol / L-0.24mol / L.

[0019] In one embodiment of the present application, in S3, the concentration of the monomer is 0.08 mol / L-0.16 mol / L, for example, it can be 0.08 mol / L, 0.09 mol / L, 0.10 mol / L, 0.11 mol / L, 0.12 mol / L, 0.13 mol / L, 0.14 mol / L, 0.15 mol / L, 0.16 mol / L. The higher the concentration of the monomer solution, the better the photothermal effect. However, too much monomer will cause problems such as agglomeration, blockage or waste during polymerization.

[0020] In one embodiment of the present application, in S3, the drying is 60-80℃ drying for 60-90min.

[0021] In one embodiment of the present application, in S4, the number of fibers supported during weaving is 12-20, for example, it can be 12, 13, 14, 15, 16, 17, 18, 19, 20; the number of composite yarns is 1-10, for example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

[0022] In one embodiment of the present application, in S4, the loop density of the composite loop yarn is 0.8g / cm 3 -1.6g / cm 3 , for example, it can be 0.8g / cm 3 , 0.9g / cm 3 , 1.0g / cm 3 , 1.1g / cm 3 , 1.2g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 ; the loop density affects the number of water supply yarns and the distribution of pores, the greater the density, the greater the water supply substrate content, the more abundant and fine the pores, and the faster the water transmission supply. For evaporation, the amount of water supply needs to be adjusted to ensure energy utilization efficiency. The loop height is 1mm-5mm, for example, it can be 1mm, 2mm, 3mm, 4mm, 5mm. The loop height increases the specific surface area, providing active sites for fog capture and condensation. Due to the limitation of the volume density of loop distribution, when the loop height reaches the peak, the moisture absorption performance will reach saturation, and if the loop height is further increased, the mechanical stability of the device will be poor.

[0023] In one embodiment of the present application, the preparation process of the composite loop yarn in S4 and the preparation of the three-dimensional loop knitted fabric in S5 are integrally formed, the feeding tension in the knitting process is 10 cN-50 cN, the knitting speed is 20 r / min-40 r / min, and the winding speed is 1 m / min-3 m / min.

[0024] The second object of the present application is to provide a three-dimensional loop knitted fabric prepared by the method.

[0025] The third object of the present application is to provide an application of the three-dimensional loop knitted fabric in seawater desalination.

[0026] The technical solution of the present application has the following advantages compared with the prior art:

[0027] (1) The three-dimensional loop knitted fabric in the present application can transport seawater to a polymer with light-heat conversion efficiency in an interfacial photo-thermal water evaporation system for seawater desalination. Under one solar radiation (1 sun), the evaporation rate is as high as 3.11 kg / (m 2 h). The air water collection capacity of the chloro-salt particles can achieve fog collection at night for eliminating the deposition of salt on the evaporator during the production of water by photo-thermal evaporation in the daytime. During the night environmental water capture process, the chloro-salt first forms a solid hydrate with environmental water through water ion hydrogen bonding, and the solid hydrate undergoes a phase transition to form a solid-liquid phase with further hygroscopicity. Subsequently, the solid-liquid hydrate completes the phase transition and turns into a saturated liquid solution. The size of the water droplets is improved through the interaction between water molecules. The micron-sized pores of the water transport channel shorten the diffusion path of water and facilitate rapid internal water circulation. The hydrophilic three-dimensional loop knitted fabric (IBFF) network acts as a water reservoir, and the absorbed water is finally stored under the action of gravity and flushes away the salt crystals formed in the evaporation system in the daytime. In the process of high salinity seawater desalination, the IBFF becomes clean after the dilution of salt caused by humidity overnight. When the periodic cycle desalination is carried out in 20wt% salt water, the daily fresh water production mass reaches 9 kg / m 2 .

[0028] (2) The three-dimensional loop knitted fabric in the present application in an interfacial photo-thermal water evaporation system supplies a large amount of seawater to the evaporator surface during the day for desalination and purification through the light-heat conversion effect. The salt crystals accumulated after seawater desalination at night are diluted by the hydrophilic diffusion and the humidity provided by air water collection, and the excellent water supply flux (4.1 kg / m 2 ) and the optimized pore channel distribution ensure stable and efficient seawater circulation supply. The amount of fog collected from the air at night is about 2.6 kg / m 2, the additional fog water supply can alleviate the limitations caused by the deposition of salt particles blocking the channels and the excessive concentration of circulating seawater. After the overnight self-driven salt dilution and dissolution induced by seawater circulation and fog water supply, the IBFF evaporator becomes clean and intact on the second day, and can be directly used for seawater desalination during the next day, showing its excellent stability, continuity and practicability in high salinity seawater desalination. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the drawings, in which:

[0030] Figure 1 Schematic diagram of the weaving process of the three-dimensional pile loop fabric of the present application;

[0031] Figure 2 Mechanical strength test results in Test Example 1 of the present application;

[0032] Figure 3 Flexibility and flexibility test results in Test Example 1 of the present application;

[0033] Figure 4 Full-spectrum solar light absorption rate test results in Test Example 2 of the present application;

[0034] Figure 5 Optical photograph of IBFF-Ts in Test Example 3 of the present application;

[0035] Figure 6 Performance test chart of IBFF-Ts in Test Example 3 of the present application; wherein a is the wet surface temperature of IBFF-Ts under one solar radiation (1 sun), and b is the water evaporation mass change record chart of IBFF-Ts under 1 sun;

[0036] Figure 7 Performance test chart of IBFF-T4 in Test Example 3 of the present application; wherein a is the evaporation amount of IBFF-T4 under different solar radiation intensities, and b is the periodic cycle evaporation amount and temperature of IBFF-T4;

[0037] Figure 8 Seawater desalination cycle stability test chart of IBFF-T4 in 10wt% salt water in Test Example 3 of the present application;

[0038] Figure 9 Test chart of IBFF-Hs in Test Example 4 of the present application; wherein a is the optical photograph of IBFF-Hs, b is the air water collection rate of IBFF-Hs under different humidity, and c is the air water collection process of IBFF-H4 under indoor environment;

[0039] Figure 10 The salt rejection process diagram of the evaporator in the test example 4 of the present application; wherein a is the salt rejection process of the evaporator without LiCl, b is the salt rejection process of the evaporator with LiCl;

[0040] Figure 11 The outdoor device diagram and test device diagram based on IBFF-H4 of the test example 5 of the present application;

[0041] Figure 12 The performance record of the IBFF-H4 array of the test example 5 of the present application in outdoor continuous operation for one week; wherein a is the relevant test result of 10wt% salt water, b is the relevant test result of 20wt% salt water. DETAILED DESCRIPTION

[0042] The present application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. It should be understood that the specific embodiments are only used to explain the present application, but the embodiments are not limited to the present application.

[0043] In the present application, unless otherwise specified, the technical and scientific terms used in the present application have the same meanings as those commonly understood by the person skilled in the art to which the present application belongs.

[0044] In the present application, unless otherwise specified, the term "and / or" used in the present application includes any and all combinations of one or more related listed items.

[0045] In the present application, unless otherwise specified, the experimental methods used in the embodiments of the present application are conventional methods, and the materials, reagents, etc. used are commercially available, unless otherwise specified.

[0046] In the present application, unless otherwise specified, when the terms "comprising" and / or "including" are used in the present application, it means that the features, integers, steps, operations, materials or components exist, but does not exclude the presence or addition of one or more other features, integers, steps, operations, materials, components or combinations thereof.

[0047] Example 1

[0048] Referring to Figure 1 As shown in the drawings, the three-dimensional loop knitted fabric and the preparation method thereof of the present application specifically include the following steps:

[0049] S1, the Tencel is ultrasonically stirred in anhydrous ethanol at 60℃ for 4h to remove surface impurities and contaminants, dried and immersed in a 10wt% LiCl dispersion for 4h, hygroscopic loading to load LiCl onto the Tencel to make it hydrophilic, then dried at 70℃ for 75min to obtain modified Tencel (LiCl / Tencel);

[0050] S2, the modified Tencel (LiCl / Tencel) is immersed in a 0.1wt% sodium dodecylbenzenesulfonate solution for 8min to obtain pretreated LiCl / Tencel;

[0051] S3, the pretreated LiCl / Tencel is immersed in a ferric chloride solution for 15min, then pyrrole monomer (concentration of 0.12mol / L) is added for in-situ polymerization, and polypyrrole is in-situ polymerized onto the pretreated LiCl / Tencel, which is then dried at 70℃ for 75min to obtain a composite yarn;

[0052] S4, 16 carbon fibers are wound onto the spools of a 16T-2 braider, and then the composite yarn (1-5) is fed into the braiding system from the central conduit through the pretension control device (feed tension of 10cN-50cN), the braiding speed of the 16T-2 braider is set to 30r / min, and the winding speed is 2m / min, the composite yarn with stress loading is overlapped on the carbon fibers, and reciprocates transversely on the surface of the cross-braided carbon fibers with the intermittent rotation of the disc to form a core-sheath structure of mutual entanglement, to obtain a composite loop yarn (CBY);

[0053] S5, the composite loop yarn (CBY) continues to be braided to obtain a three-dimensional loop knitted fabric (IBFF);

[0054] When the feed tension is 20cN, the number of composite yarns is adjusted to 1, 2, 3, 4, and 5 respectively to obtain composite loop yarns with loop densities of 0.8g / cm 3 , 1.0g / cm 3 , 1.2g / cm 3 , 1.4g / cm 3 , and 1.6g / cm 3 , respectively, and then different three-dimensional loop knitted fabrics (IBFF) are obtained, which are named IBFF-T1, IBFF-T2, IBFF-T3, IBFF-T4, and IBFF-T5, respectively;

[0055] When the number of composite yarns is 4, the feeding tension is adjusted to 50 cN, 40 cN, 30 cN, 20 cN and 10 cN respectively to obtain composite loop yarns with loop heights of about 1 mm, 2 mm, 3 mm, 4 mm and 5 mm respectively, and then different three-dimensional loop knitted fabrics (IBFF) are obtained, which are named IBFF-H1, IBFF-H2, IBFF-H3, IBFF-H4 and IBFF-H5 respectively.

[0056] Test Example 1

[0057] Mechanical strength tests (refer to standards DIN 53835-2, DIN 53835-2) were performed on the composite loop yarns (CBY, number of composite yarns is 4, feeding tension is 20 cN) and the smooth knitted yarns (4 composite yarns, feeding tension is 100 cN) of Example 1, and the results are shown in Figure 2 It can be seen from Figure 2 that the loop structure of the composite loop yarns improves the connection strength and ductility, alleviates the inconsistency of rupture, and improves the mechanical strength and stability. Therefore, compared with the smooth knitted yarns without loop structure, the CBY shows better mechanical strength.

[0058] The flexibility and flexibility test results of the composite loop yarns (CBY) are shown in Figure 3 It can be seen from Figure 3 that the composite loop yarns (CBY) have good flexibility and flexibility, and can be easily knotted, stretched and bent into various shapes, which is conducive to subsequent textile processing and device preparation.

[0059] Test Example 2

[0060] The original Tencel, LiCl / Tencel of Example 1, the composite loop yarns (CBY) of Test Example 1 and the smooth knitted yarns were tested for full-spectrum solar light absorption rate (refer to standard JB / T 6778-1993), and the results are shown in Figure 4 It can be seen from Figure 4It can be seen that the original Tencel has a weak full-spectrum solar energy absorption capacity of only 56.8%; after loading with LiCl, the overall solar energy absorption capacity of LiCl / Tencel has almost no change, indicating that the loading of the hydrophilic salt LiCl does not destroy the structure of the original Tencel, and the yarn structure remains intact; after in-situ polymerization of polypyrrole, the light absorption rate of the smooth woven yarn without the structure of the loop is 87.3%. This is because polypyrrole has a wide wavelength absorption characteristic and can absorb most of the visible light and infrared light. When sunlight shines on the surface of the polypyrrole material, light energy is absorbed. The absorbed light energy causes the excitation and vibration of the electrons inside the polypyrrole molecules, thereby generating heat energy. This energy conversion is achieved through the absorption and conversion of light energy into the transition between electronic energy levels and vibration energy levels. After weaving with loops, the light absorption rate of CBY reaches 94.1%, because the incident light can be reflected and absorbed between the loop structures in multiple stages, increasing the absorption rate of sunlight, and the excellent light absorption performance ensures the supply of photothermal energy of IBFF in the process of seawater desalination.

[0061] Test Example 3

[0062] (1) The composite loop yarn (CBY) of Example 1 was used as the core layer of the mechanical support with carbon fibers of the same diameter, and the loop density was adjusted by adjusting the number of composite yarns. The corresponding IBFF-Ts showed different physical forms, water supply capacity and photothermal water evaporation performance, and the optical photograph of IBFF-Ts is shown in Figure 5 . It can be seen from Figure 5 that the IBFF-Ts with increased loop density show higher thickness and compactness, which leads to a more intensive water circulation network.

[0063] (2) The water supply flux of IBFF-Ts was tested (the maximum water content per unit area of the sample), and through calculation, the water supply fluxes of IBFF-T1, IBFF-T2, IBFF-T3, IBFF-T4 and IBFF-T5 were 1.4 kg / m 2 , 2.4 kg / m 2 , 3.1 kg / m 2 , 4.1 kg / m 2 and 4.3 kg / m 2 , respectively. The enhanced water supply capacity is attributed to the strong hydrophilicity of the composite yarn and the better distribution of the water circulation network.

[0064] The wet surface temperature of IBFF-Ts under one solar radiation (1 sun) was measured with a thermocouple, and the sensing probe of the thermocouple was placed on the surface of the object to be measured, and the results are shown in Figure 6 a. It can be seen from Figure 6It can be seen that the wet surface temperature reached equilibrium after 10 min of irradiation, and the stable temperature decreased with the increase of the pile density. The rapid heating of IBFF-Ts under solar irradiation proved the fast photothermal response of the composite yarn. The wet evaporation temperature of the device surface was consistent with the water supply gradient trend, and the higher temperature was due to the less water supply and the high heat generated by the interfacial photothermal conversion, most of which was wasted. The lower stable temperature was attributed to the excessive water supply, and the balance between energy input and water supply during photothermal water evaporation was a key factor for efficient energy utilization. Water shortage led to a large amount of conduction and convection loss, while excessive water supply wasted energy on heating instead of accelerating evaporation.

[0065] The evaporation rate of the device was the evaporation mass per unit area per unit time, and the change of evaporation mass with time was recorded by an electronic balance continuously, and the evaporation area was measured directly. The evaporation rates of IBFF-T1, IBFF-T2, IBFF-T3, IBFF-T4 and IBFF-T5 were 2.44 kg / (m 2 h), 2.59 kg / (m 2 h), 2.75 kg / (m 2 h), 3.11 kg / (m 2 h), 3.01 kg / (m 2 h) under one solar irradiation (1 sun), respectively. Figure 6 As shown in b, the evaporation mass of IBFF-T4 under 0.4 sun, 0.7 sun, 1 sun and 1.3 sun was 1.43 kg / (m 2 h), 2.15 kg / (m 2 h), 3.11 kg / (m 2 h), 3.95 kg / (m 2 h), respectively. Figure 7 As shown in a, the periodic cycle evaporation mass and temperature of IBFF-T4 were as shown in b, and the evaporation mass and temperature of IBFF-T4 were as shown in c. Figure 7 b, Figure 6 b, Figure 7 It can be seen that due to the multi-stage light absorption of the rough surface, the optimized energy conversion efficiency, and the large specific surface area of the three-dimensional structure, the optimal evaporation rate of IBFF-T4 was 3.11 kg / (m 2 h). With the increase of solar intensity, the wet surface temperature showed a gradient improvement, and even under weak irradiation (0.4 sun), the evaporation rate reached 1.43 kg / (m 2 h), which showed strong adaptability to run under different light intensities. Due to the stable load and excellent mechanical strength, the surface temperature and evaporation mass change of the device remained stable within 10 operation cycles, ensuring the practicability and stability of long-time operation.

[0066] (3) IBFF-T4 was placed in 10wt% salt water to carry out seawater desalination cycle stability test, 8 hours for each cycle, after the cycle, the device was cooled to room temperature, and then the next cycle was started, the test results are shown in Figure 8 Figure 8 It can be seen that after 10 cycles (8h for each cycle) of desalination in 10wt% salt water, IBFF-T4 evaporator remains clean and intact, indicating that the device has excellent salt resistance. This is because of its strong hydrophilicity and optimized water channel distribution, the natural cracks on the fibers and the inter-fiber gaps provide abundant pathways for capillary pumping and water diffusion. Therefore, under the mechanism of hydrophilic horizontal flow diffusion, IBFF-T4 with optimized pore distribution can achieve stable cycle salt rejection in low concentration seawater (10wt%).

[0067] Test Example 4

[0068] (1) The composite loop yarn (CBY) of Example 1 was used as the core layer of mechanical support with carbon fibers of the same diameter, and the loop height was adjusted by adjusting the feeding tension of the composite yarn. The optical photo of the corresponding IBFF-Hs is shown in Figure 9 a, and the increased loop height of IBFF-Hs means more active sites for air water collection. The large contact area with the ambient humidity is conducive to the adsorption of humidity, and sufficient moisture rapidly enters the IBFF evaporator at night and conducts in the evaporator, and finally adheres to the fiber surface or fills in the inter-fiber pores, and removes the salt crystals generated by the evaporation of the light and heat water during the day under the action of gravity.

[0069] (2) The ambient temperature and humidity were adjusted by air humidifier and dehumidifier, and the IBFF was placed on the balance to record the mass change readings in real time. The air water collection rate of IBFF-Hs at different humidity is shown in Figure 9 b, and the air water collection process of IBFF-H4 under indoor conditions is recorded by cell dynamic observation instrument as shown in Figure 9 c. From Figure 9 b-9c, it can be seen that as the loop height increases, the moisture absorption performance of the device gradually increases, and IBFF-H4 has excellent moisture absorption performance under indoor conditions. For IBFF-H5 with further increased loop height, the environmental moisture trapping air water collection efficiency does not improve significantly due to saturation absorption. For IBFF-H4 with excellent air water collection capacity, sufficient moisture can be collected for salt dilution under indoor conditions without solar radiation.

[0070] (3) Based on IBFF-H4, salt rejection tests were carried out on the evaporators with and without LiCl under indoor conditions, and the IBFF was placed in simulated seawater with a salt concentration of 20wt% to carry out water evaporation test, and the evaporation mass change was recorded, and the results are shown in​Figure 10 As shown in FIG. 6, the IBFF-H4 evaporator with air condensation assistance for salt hygroscopicity was not clogged by salt particles even after long time of advection diffusion. In contrast, the evaporator without LiCl (evaporator without air condensation assistance for salt hygroscopicity) was clogged by salt particles after long time of advection diffusion. The clogged salt particles in the evaporator without LiCl were completely removed, and the cleaned evaporator could continue to be used for seawater desalination with high efficiency and stability. Figure 10 As shown in FIG. 6, the IBFF-H4 evaporator with air condensation assistance for salt hygroscopicity was not clogged by salt particles even after long time of advection diffusion. In contrast, the evaporator without LiCl (evaporator without air condensation assistance for salt hygroscopicity) was clogged by salt particles after long time of advection diffusion. The clogged salt particles in the evaporator without LiCl were completely removed, and the cleaned evaporator could continue to be used for seawater desalination with high efficiency and stability.

[0071] Test Example 5

[0072] As shown in FIG. 6, the IBFF-H4 evaporator with air condensation assistance for salt hygroscopicity was not clogged by salt particles even after long time of advection diffusion. In contrast, the evaporator without LiCl (evaporator without air condensation assistance for salt hygroscopicity) was clogged by salt particles after long time of advection diffusion. The clogged salt particles in the evaporator without LiCl were completely removed, and the cleaned evaporator could continue to be used for seawater desalination with high efficiency and stability. Figure 11 As shown in FIG. 7, the IBFF-H4 was used for outdoor seawater desalination and salt removal test in a 3x3 array. The detachable cover of the super-transparent glass condenser was suitable for photothermal water evaporation during the day and air condensation at night. The performance record of the IBFF-H4 array in outdoor continuous operation for one week is shown in FIG. 7. As shown in FIG. 7, the IBFF-H4 evaporator with air condensation assistance for salt hygroscopicity was not clogged by salt particles even after long time of advection diffusion. In contrast, the evaporator without LiCl (evaporator without air condensation assistance for salt hygroscopicity) was clogged by salt particles after long time of advection diffusion. The clogged salt particles in the evaporator without LiCl were completely removed, and the cleaned evaporator could continue to be used for seawater desalination with high efficiency and stability. Figure 12 As shown in FIG. 7, the IBFF-H4 evaporator with air condensation assistance for salt hygroscopicity was not clogged by salt particles even after long time of advection diffusion. In contrast, the evaporator without LiCl (evaporator without air condensation assistance for salt hygroscopicity) was clogged by salt particles after long time of advection diffusion. The clogged salt particles in the evaporator without LiCl were completely removed, and the cleaned evaporator could continue to be used for seawater desalination with high efficiency and stability. Figure 12 As shown in FIG. 7, the IBFF-H4 evaporator with air condensation assistance for salt hygroscopicity was not clogged by salt particles even after long time of advection diffusion. In contrast, the evaporator without LiCl (evaporator without air condensation assistance for salt hygroscopicity) was clogged by salt particles after long time of advection diffusion. The clogged salt particles in the evaporator without LiCl were completely removed, and the cleaned evaporator could continue to be used for seawater desalination with high efficiency and stability. 2 After long time of seawater desalination in 20wt% seawater during the day, salt crystals were formed on the surface of the IBFF-H4. After nightfall, the condensed water during the day was collected, and the transparent cover was removed for air condensation at night. Finally, after the auxiliary effect of fog condensation driving salt dilution for the whole night, the IBFF-H4 evaporator became clean again without manual removal of salt, and could be directly used for seawater desalination the next day. In 20wt% seawater, the calculated outdoor condensed water quality per day was more than 9kg / m 2 , and the water collection amount at night was calculated to be about 2.6kg / m 2 , which was crucial for salt dilution caused by water. After one week of cycle test, the desalination rate of the device remained high and stable, which proved the strong adaptability of IBFF under different outdoor conditions and the durability after long time of operation, greatly guaranteeing the practicality of the device.

[0073] In conclusion, the present application optimizes the seawater desalination and air water collection performance by changing the loop density and loop height of the composite loop yarn, and then prepares the three-dimensional loop knitted fabric (IBFF) with the water-induced salt dilution function, which has excellent hydrophilicity and interconnected porous water transport channels. The hydrophilic advection-diffusion mechanism drives the rapid circulation of salt water, which can continuously and stably desalinate seawater in low-concentration seawater desalination. With the assistance of night fog collection, combined with the advection-diffusion mechanism, the spontaneous dilution of salt particles can be promoted, which guarantees the periodic and stable seawater desalination in high-salinity seawater desalination.

[0074] Obviously, the above examples are only examples for clearly illustrating, not limiting the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments cannot be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method of making a three-dimensional terry knit fabric, characterized by, The method comprises the following steps: S1, dipping a hydrophilic substrate into a chlorine salt solution, and drying to obtain a modified hydrophilic substrate; the hydrophilic substrate is selected from one or more of Tencel, cotton, acetate fiber and wool; the chlorine salt is selected from one or more of lithium chloride, calcium chloride and potassium chloride; the concentration of the chlorine salt solution is 5wt%-10wt%; S2, dipping the modified hydrophilic substrate of S1 into a surfactant solution for pretreatment to obtain a pretreated hydrophilic substrate; the surfactant is selected from sodium dodecyl benzene sulfonate and / or sodium dodecyl sulfate; the concentration of the surfactant solution is 0.05wt%-0.2wt%; S3, dipping the pretreated hydrophilic substrate of S2 into an oxidant solution for 10min-30min, then adding a monomer for in-situ polymerization, and drying to obtain a composite yarn; the monomer is selected from one or more of pyrrole, dopamine and aniline; the concentration of the monomer is 0.08mol / L-0.16mol / L; the oxidant is selected from one or more of ferric chloride, ammonium persulfate, sodium persulfate and potassium persulfate; the concentration of the oxidant solution is 0.12mol / L-0.24mol / L; S4, weaving the composite yarn of S3 on supporting fibers by a weaving machine to obtain a composite loop yarn; wherein the supporting fibers are interlaced to form a woven structure, a part of each composite yarn is embedded in the woven structure under the weaving force of the supporting fibers, and the other part is accumulated on the outer layer of the woven structure to form a loop structure due to stress relaxation; the supporting fibers are selected from one or more of carbon fiber, polyphenylene terephthalamide fiber, graphite fiber and silicon carbide fiber; S5, weaving the composite loop yarn of S4 by a weaving machine to obtain a three-dimensional loop fabric.

2. The method of claim 1, wherein the three-dimensional looped fabric is formed by knitting the first and second yarns in the first and second courses, respectively. In S4, the number of supporting fibers in the weaving process is 12-20, and the number of composite yarns is 1-10.

3. The method of claim 1, wherein the three-dimensional loop pile fabric is prepared by the steps of: In S4, the terry density of the composite terry yarn is 0.8 g / cm 3 -1.6 g / cm 3 , and the terry height is 1 mm-5 mm.

4. The method of claim 1, wherein the three-dimensional loop pile fabric is prepared by the steps of: The preparation process of the composite loop yarn in S4 and the preparation of the three-dimensional loop fabric in S5 are integrally formed, the feeding tension in the weaving process is 10cN-50cN, the weaving speed is 20r / min-40r / min, and the winding speed is 1m / min-3m / min.

5. A three-dimensional loop fabric prepared by the method of any one of claims 1-4.

6. Use of the three-dimensional loop fabric of claim 5 in seawater desalination.

Images