Preparation method of foam composite self-floating sponge and photo-thermal interface evaporation application of foam composite self-floating sponge

Abstract

The invention discloses a preparation method of foam composite self-floating sponge and photo-thermal interface evaporation application of the foam composite self-floating sponge. In the foaming process of preparing the porous sponge, the step of adding hydrophobic foam particles in situ is introduced, and the composite material which can rapidly absorb and guide water and has the self-floating characteristic is prepared through a one-step method. The composite material disclosed by the invention can simultaneously meet the dual functions of water absorption, water diversion and self-floating. When the composite material is used as a substrate material of a photo-thermal interface evaporation system, a spontaneous, continuous and stable outdoor evaporation process can be ensured. Under the condition of simulating 1 solar radiation (1000 W / m < 2 >), the technology realizes the water evaporation rate up to 1.86 kg.m <-2 >. H <-1 >; and under natural sunlight irradiation (about 435 W / m < 2 >), the average sewage evaporation rate reaches 1.70 kg.m <-2 >. H <-1 >, and the daily average sewage evaporation capacity is 12.0-14.0 kg.m <-2 >.

Description

Technical Field

[0001] The invention belongs to the technical field of solar thermal interface evaporation, and specifically relates to a preparation method of a foam composite self-floating sponge and its photothermal interface evaporation application. Background Art

[0002] Solar thermal evaporation is a natural process that occurs all the time in nature and is one of the important links in the hydrological cycle in nature. Its energy source is the sun, and its applications include seawater desalination, sterilization and disinfection, fresh water acquisition, sewage treatment, etc. As a natural process, solar thermal interface evaporation shows unique advantages in sewage treatment: no specific sewage type and concentration restrictions are required, the effluent quality is high, no equipment investment and maintenance are required, energy consumption is zero, and it occupies a small area, and the device is flexible and movable. However, despite the obvious advantages, there are few reports on the practical application of this technology, mainly due to the much lower sewage treatment rate compared with conventional industrial methods, and the technical difficulties of existing solar thermal interface evaporators that make it difficult to achieve simplified and low-cost preparation of large-size samples and spontaneous, long-term continuous and stable evaporation. Summary of the invention

[0003] In view of this, the present invention designs and prepares a foam composite self-floating sponge material, which is specially used in the base layer of the photothermal interface evaporator. The material successfully realizes continuous and stable outdoor solar evaporation wastewater treatment without external intervention, demonstrating its high efficiency and stability in practical applications.

[0004] The present invention introduces a step of in-situ adding hydrophobic foam particles during the foaming process of preparing a porous sponge, thereby realizing a one-step method for preparing a composite material that can quickly absorb and conduct water and has self-floating properties. By adjusting the addition ratio of the foam particles, the floating height of the composite material on the liquid surface can be conveniently adjusted. By using this composite material as the substrate of a photothermal interface evaporator and combining it with a photothermal interface evaporation layer, a large-scale, simplified, low-cost photothermal interface evaporator can be manufactured. The evaporator can spontaneously, continuously and stably perform evaporation operations for a long time, making full use of solar energy for sewage treatment.

[0005] The method for preparing the foam composite self-floating sponge of the present invention comprises the following steps:

[0006] Step 1: Mix the sponge foaming raw material liquid and the foaming curing liquid (Haibei 901 high resilience material combination, purchased from Beijing Haibei Company) in a certain proportion, place in a flat-bottomed container, and quickly stir mechanically to make it uniform. The stirring time is controlled within 1 minute;

[0007] Step 2: Mix a certain proportion of foam particles into it, quickly stir it mechanically and evenly, and the time is controlled within 2 minutes; let it stand for 5 to 10 minutes to complete foaming and drying, and cut the sponge foam composite material into sheets with a thickness of 1 to 10 cm;

[0008] Step 3: mixing the photothermal conversion substance and the hydrogel matrix material to obtain a pre-gelled composite liquid;

[0009] Step 4: immerse one side of the sheet-like sponge foam composite material prepared in step 2 in the pre-gelled composite liquid prepared in step 3, and obtain a self-floating foam / sponge / hydrogel composite material after the hydrogel is cured.

[0010] In step 1, the sponge comprises one or more of melamine, polyurethane, polyester, polyether, and polyvinyl alcohol, preferably melamine or polyurethane.

[0011] In step 2, the foam comprises one or more of polystyrene, polyurethane, polyethylene, polypropylene, plastic, and rubber foam materials, preferably spherical particles, which may be solid or hollow, and the particle (equivalent) diameter is 2 to 10 mm.

[0012] In step 2, the ratio of the foam volume to the sponge volume is 1 to 4:8. The foam is a low-density, large-discharge volume material, and the height of the overall evaporator above the liquid level can be adjusted by adjusting the ratio of the foam to the sponge, which is closely related to the appropriate water supply capacity.

[0013] In step 2, the porosity after foaming is controlled to be 70% to 99%, preferably 80% to 90%; the pore size distribution is controlled to be 20 μm to 2 mm, preferably 200 to 600 μm. The sponge foam composite material after foaming is cut into sheets with a thickness of 1 to 10 cm, preferably 3 to 7 cm. This thickness is the thickness of the main material, that is, the thickness of the solar thermal interface evaporator.

[0014] In step 3, the photothermal conversion substance is activated carbon powder. The hydrogel matrix material includes one or more of polyvinyl alcohol hydrogel, polyacrylamide hydrogel, polyacrylic acid hydrogel, and polysaccharide hydrogel, and the mass fraction of activated carbon powder in the hydrogel prepolymer solution is 1 wt%.

[0015] In the present invention, the hydrogel composite material is arranged on one side of the sponge foam composite material to form a photothermal evaporation layer with a thickness of 0.2 to 10 mm, preferably 1 to 3 mm. The loading amount of the photothermal conversion material composite hydrogel matrix on the surface of the sponge sheet is 0.2 to 4 g / cm 2 , preferably 1.0~3.0 g / cm 2 .

[0016] The invention discloses an application of the foam composite self-floating sponge material in photothermal interface evaporation.

[0017] The sponge foam composite material prepared by the invention is used to realize the self-floating and continuous water guiding and supplying functions of the photothermal interface evaporator, and can be applied to solar energy evaporation sewage treatment.

[0018] The raw materials selected by the present invention, namely sponge, foam, photothermal conversion material and synthetic hydrogel raw materials, are low in price, no equipment expenditure is required, and the cost is effectively controlled.

[0019] The size of the sponge foam composite material prepared by the present invention depends on the selection of the foaming container, which ensures the simplicity of preparing a large-sized self-floating base layer.

[0020] The hydrogel synthesis method selected by the present invention is simple and can quickly gel at room temperature. The gelation process can be carried out in situ in the sponge gap, and the thickness of the photothermal interface evaporation layer can be easily controlled, ensuring the simplified and low-cost preparation of a large-scale evaporator.

[0021] The sponge material selected in the present invention provides excellent bottom-up water supply capability, which ensures the continuous stability of the evaporation process of the evaporator.

[0022] The foam material selected in the present invention endows the sponge material and the evaporator as a whole with self-floating properties, so that the evaporator can rise and fall with the liquid level and maintain a stable water supply capacity, which ensures the spontaneous and long-term continuous stability of the evaporation process of the evaporator.

[0023] The present invention combines the high light absorption (light absorption rate of about 86%) of the photothermal conversion material, the heat conversion, the thermal localization of the photothermal evaporation layer, the 3D support of the sponge material and the excellent bottom-up water supply capacity, the high thermal insulation capacity and self-floating performance of the foam, and the preferred room temperature in-situ gelation hydrogel system to achieve a simplified and low-cost preparation of a large-scale evaporator and spontaneous, long-term continuous and stable evaporation performance. The preparation cost of the solar photothermal interface evaporator is about 65 yuan / m 2 ; When treating actual sewage, the system was operated for 24 hours for 10 days (the highest solar intensity was about 435 W / m 2 ), the average daily water evaporation rate during the day is 1.70 kg·m -2 ·h -1 , which is significantly higher than the direct evaporation rate of sewage under the same conditions by 1.10 kg·m -2 ·h -1 The average water evaporation rate during the daytime remained stable within 10 days, and the average daily sewage treatment volume was 12.0 ~ 14.0 kg·m -2 .

[0024] The solar thermal evaporator of the present invention is a low-cost and efficient solar interface evaporation system with functional zoning, simple process, almost no operation required, easy large-scale preparation, high energy utilization rate, high degree of spontaneous operation, small footprint, high flexibility, and low maintenance cost. It can be used for sewage treatment, especially sewage treatment, and has good economic and environmental benefits and prospects for promotion in civil and commercial use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the surface of the PU sponge / PS foam composite material in Example 1 of the present invention.

[0026] Figure 2 This is the surface of the PU sponge / PS foam / SA hydrogel composite material in Example 2 of the present invention.

[0027] Figure 3 : This is the evaporation curve of the PU sponge / PS foam / SA hydrogel composite material in Example 2 of the present invention under simulated 1 sun.

[0028] Figure 4 This is the evaporation curve of the PU sponge / PS foam / SA hydrogel composite material in Example 2 of the present invention under actual sunlight on September 8, 2024 (sample 1, 2, and 3 are three parallel sample tests).

[0029] Figure 5 It is the average daily maximum water evaporation rate of the PU sponge / PS foam / SA hydrogel composite material in Example 3 of the present invention under actual sunlight from September 2 to 12, 2024 (sample 1, 2, and 3 are three parallel sample tests).

[0030] Figure 6 It is the average daily sewage evaporation of the PU sponge / PS foam / SA hydrogel composite material in Example 4 of the present invention under actual sunlight from September 2 to 12, 2024 (sample 1, 2, and 3 are three parallel sample tests). DETAILED DESCRIPTION

[0031] The present invention provides a self-floating solar photothermal interface evaporator, comprising a photothermal interface evaporation layer and a self-floating base layer; the photothermal interface evaporation layer comprises a hydrogel material and a photothermal conversion substance dispersed therein, and a pre-gelled solution mixed with the photothermal conversion substance is prepared by in-situ gelation in the gap on one side of a sponge; the self-floating base layer comprises a sponge and foam.

[0032] Unless otherwise specified, the sources of the raw materials of the present invention have no special requirements, and common commercial products known to those skilled in the art can be directly used.

[0033] The self-floating solar thermal interface evaporator provided by the present invention includes a sponge. The sponge is porous, and the material is preferably melamine, polyurethane, polyester, polyether or polyvinyl alcohol, more preferably melamine or polyurethane; the porosity of the sponge is preferably 70% to 99%, more preferably 80% to 90%, and the internal pore size distribution is preferably 20 μm to 2 mm, more preferably 200 to 600 μm. Cut the flat sheet sponge according to the required size, the thickness is preferably 1 to 10 cm, more preferably 3 to 7 cm. The area is preferably 0.5 m × 0.5 m and 1.0 m × 1.0 m, or other sizes can be adjusted and cut according to the actual sewage treatment scale.

[0034] The self-floating solar thermal interface evaporator provided by the present invention includes foam. The foam shape is preferably spherical particles; the foam material is preferably polystyrene, polyurethane, polyethylene, polypropylene, plastics, rubber, and more preferably polystyrene; the foam and sponge are composited in a way that foam particles are in situ doped during the synthesis of the sponge.

[0035] The self-floating solar thermal interface evaporator provided by the present invention comprises a photothermal conversion material, which is preferably one or more of metal particles, carbon materials, organic small molecules, polymers and biomass materials, and more preferably activated carbon powder among carbon materials.

[0036] The self-floating solar thermal interface evaporator provided by the present invention comprises a hydrogel matrix, preferably one or more of polyvinyl alcohol hydrogel, polyacrylamide hydrogel, polyacrylic acid hydrogel, and polysaccharide hydrogel, more preferably polyvinyl alcohol hydrogel or sodium alginate / calcium ion hydrogel; the water content of the hydrogel is preferably 50% to 98%, more preferably 80% to 95%.

[0037] The self-floating solar thermal interface evaporator provided by the present invention comprises a thermal interface evaporation layer, the thickness of which is preferably 0.2 to 10 mm, more preferably 1 to 3 mm. The loading amount of the photothermal conversion material composite hydrogel matrix on the surface of the sponge sheet is preferably 0.2 to 4 g·cm -2 , more preferably 1.0~3.0 g·cm -2 .

[0038] The present invention combines the high light absorption (light absorption rate of about 86%) of the photothermal conversion material, thermal conversion, thermal localization of the photothermal evaporation layer, 3D support and excellent bottom-up water supply capacity of the sponge material, high thermal insulation capacity and self-floating performance of the foam, and anisotropic functional zoning design to ensure functional requirements and save material usage, and optimizes the room temperature in-situ gelling hydrogel system to achieve simplified and low-cost preparation of large-scale evaporators and spontaneous, long-term continuous and stable evaporation performance.

[0039] The present invention also provides a method for preparing the floating solar evaporator described in the above technical solution, comprising the following steps:

[0040] In-situ doping of foam particles during the sponge synthesis process;

[0041] The photothermal conversion material and various raw materials for synthesizing hydrogel are mixed in a certain proportion to obtain a pre-gelled composite liquid, and the prepared sponge / foam composite material is immediately immersed in the pre-gelled composite liquid and waited for solidification to obtain a self-floating sponge / foam / hydrogel solar thermal interface evaporator.

[0042] The present invention combines the high light absorption (light absorption rate of about 86%) of the photothermal conversion material, the heat conversion, the thermal localization of the photothermal evaporation layer, the 3D support of the sponge material and the excellent bottom-up water supply capacity, the high thermal insulation capacity and self-floating performance of the foam, and the preferred room temperature in-situ gelation hydrogel system to achieve a simplified and low-cost preparation of a large-scale evaporator and spontaneous, long-term continuous and stable evaporation performance. The preparation cost of the solar photothermal interface evaporator is about 65 yuan / m 2 ; When treating actual sewage, the system was operated for 24 hours for 10 days (the highest solar intensity was about 435 W / m 2 ), the average daily evaporation rate is 1.70 kg·m -2 ·h -1 , which is much higher than the direct evaporation rate of sewage under the same conditions, which is 1.10 kg·m -2 ·h -1 The average daily evaporation rate remained stable within 10 days, and the average daily sewage treatment volume was 12.0 ~ 14.0 kg·m -2 .

[0043] The solar thermal evaporator of the present invention is a low-cost and efficient solar interface evaporation system with functional zoning, simple process, almost no operation required, easy large-scale preparation, high energy utilization rate, high degree of spontaneous operation, small footprint, high flexibility, and low maintenance cost. It can be used for sewage treatment, especially sewage treatment, and has good economic and environmental benefits and prospects for promotion in civil and commercial use.

[0044] The present invention also provides the use of the floating solar evaporator described in the above technical solution or the self-floating solar thermal interface evaporator prepared by the preparation method described in the above technical solution in sewage treatment and / or sewage treatment.

[0045] The present invention has no special limitation on the application of the self-floating solar thermal interface evaporator in sewage treatment and / or wastewater treatment, and any application method known in the art may be used.

[0046] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0047] Embodiment 1:

[0048] Weigh 10 g of polyurethane foaming liquid, add 0.8 g of PS foam ball particles (diameter 3-5 mm) to it, mix well, add 4 g of sponge foaming curing agent, and foaming is completed after about 2 minutes to obtain PU sponge / PS foam composite material, which is cut into sheets with a thickness of 3 cm and used as the self-floating base layer of solar thermal interface evaporator (see Figure 1 In subsequent tests, this sample was used as a reference sample for photothermal evaporation testing (i.e. Figure 4 , 5 , PU sponge sample in 6).

[0049] Embodiment 2:

[0050] The preparation of the PU sponge / PS foam composite material is consistent with that in Example 1.

[0051] Weigh 10.0 g of 2 wt% sodium alginate (SA) aqueous solution, add 0.10 g of activated carbon powder, and stir mechanically to evenly disperse the activated carbon powder. -2 The amount of PU sponge / PS foam was absorbed on one side, and then immersed in a 2 wt% CaCl2 aqueous solution. After 30 min, gelation was completed, and a floating PU sponge / PS foam / SA hydrogel solar thermal interface evaporator was prepared (see Figure 2 ).

[0052] Processing Example:

[0053] Treatment of actual sewage under natural environment: The solar thermal interface evaporator in Example 2 was used. The actual sewage sample was sewage from a small pond on the campus of Anhui University. The sewage was placed in an open circular container with a height of 0.16 m and a radius of 5 cm. The sewage height was 0.15 m and covered with the solar thermal interface evaporator in Example 1. The solar thermal evaporation experiment was carried out in a sunny and well-ventilated place. A reference experimental group was also set up. The only difference was that no objects were covered, so that the sewage was allowed to evaporate naturally under the same conditions. The experiment started at 8:00 every day and ended at 17:00. The mass of the entire experimental system was weighed at the beginning of the experiment and every hour, and the water evaporation rate (kg·m -2 ·h -1), while recording the actual solar radiation intensity and wind speed data. Continue the experiment for 24 hours, and calculate the average daily evaporation, that is, the average daily sewage treatment rate (kg·m -2 ). The test was conducted continuously for 10 days from September 2 to 12, 2024 (September 11 was cloudy and rainy, so no data was collected). Three parallel samples were tested at the same time (sample 1, 2, and 3). The evaporation curve for September 8, 2024 is given as follows: Figure 4 The average daily maximum water evaporation rate data under actual sunlight from September 2 to 12, 2024 is as follows Figure 5 The average daily sewage evaporation data under actual sunlight from September 2 to 12, 2024 is as follows: Figure 6 shown.

[0054] Performance test data:

[0055] In Example 2, the sample was subjected to pure water evaporation under simulated 1 sun, and the evaporation rate was 1.86 kg·m -2 ·h -1 (See Figure 3 ).

[0056] In the actual sewage natural environment (the highest sunlight intensity is about 435 W / m 2 The average maximum photothermal evaporation rate of the photothermal interface evaporator in the 10-day treatment in Example 1 was 1.81 kg·m -2 ·h -1 (See Figure 5 ), with an average daily sewage treatment volume of 13.1 kg·m -2 (See Figure 6 ).

[0057] In the actual sewage natural environment (the highest sunlight intensity is about 435 W / m 2 The average maximum photothermal evaporation rate of the photothermal interface evaporator in the 10-day treatment of Example 2 was 1.62 kg·m -2 ·h -1 (See Figure 5 ), with an average daily sewage treatment capacity of 12.5 kg·m -2 (See Figure 6 ).

[0058] In the actual sewage natural environment (the highest sunlight intensity is about 435 W / m 2 The average maximum photothermal evaporation rate of the photothermal interface evaporator in the 10-day treatment of Example 3 was 1.67 kg·m -2 ·h -1 (See Figure 5 ), with an average daily sewage treatment capacity of 12.5 kg·m -2(See Figure 6 Since this experiment was conducted in early September 2024, the actual maximum daytime sunlight intensity was only 1sun (1000 W / m 2 ), and it is expected that the actual sewage treatment rate under normal summer outdoor conditions will be higher.

[0059] It can be seen that this self-floating sponge / foam / hydrogel solar thermal interface evaporator has excellent spontaneous continuous stability. Compared with the reference group, it significantly improves the sewage treatment rate. It relies only on solar energy, has low cost and good flexibility. Its promotion and application will have good economic and environmental benefits.

[0060] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

[0061] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a foam composite self-floating sponge, characterized in that The steps include: Step 1: Mix the sponge foaming raw material liquid and the foaming curing liquid, place them in a flat-bottomed container, and quickly stir them mechanically until they are uniform. The stirring time should be controlled within 1 minute. Step 2: Add the foam particles to the system of step 1, and stir them evenly mechanically for less than 2 minutes; let them stand for 5 to 10 minutes to complete foaming and drying, and cut the sponge foam composite material into sheets with a thickness of 1 to 10 cm; Step 3: mixing the photothermal conversion substance and the hydrogel matrix material to obtain a pre-gelled composite liquid; Step 4: immerse one side of the sheet-like sponge foam composite material prepared in step 2 in the pre-gelled composite liquid prepared in step 3, and obtain a self-floating foam / sponge / hydrogel composite material after the hydrogel is cured.

2. The preparation method according to claim 1, characterized in that: In step 1, the sponge includes one or more of melamine, polyurethane, polyester, polyether, and polyvinyl alcohol.

3. The preparation method according to claim 1, characterized in that: In step 2, the foam includes one or more of polystyrene, polyurethane, polyethylene, polypropylene, plastic, and rubber foam materials.

4. The preparation method according to claim 3, characterized in that: The foam is solid or hollow spherical particles with a diameter of 2 to 10 mm.

5. The preparation method according to claim 1, characterized in that: In step 2, the ratio of the foam volume to the sponge volume is 1-4:

8.

6. The preparation method according to claim 1, characterized in that: In step 2, the porosity after foaming is controlled at 70% to 99%, the pore size distribution is controlled at 20 μm to 2 mm, and the thickness is 1 to 10 cm.

7. The preparation method according to claim 1, characterized in that: In step 3, the photothermal conversion substance is activated carbon powder; the hydrogel matrix material includes one or more of polyvinyl alcohol hydrogel, polyacrylamide hydrogel, polyacrylic acid hydrogel, and polysaccharide hydrogel.

8. The preparation method according to claim 7, characterized in that: The photothermal conversion substance accounts for 1 wt% of the mass of the pre-gelled composite liquid; the loading amount of the pre-gelled composite liquid on the surface of the sponge sheet is 0.2-4 g / cm 2 .

9. The preparation method according to claim 1, characterized in that: The hydrogel composite material is arranged on one side of the sponge foam composite material to form a photothermal evaporation layer with a thickness of 0.2-10 mm.

10. Use of the foam composite self-floating sponge material prepared by the preparation method according to any one of claims 1 to 9 in photothermal interface evaporation.

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