A highly salt-resistant zwitterionic polymer-modified photothermal material, its preparation method and application

Abstract

This invention belongs to the field of photothermal conversion materials technology, specifically relating to a highly salt-resistant zwitterionic polymer-modified photothermal material, its preparation method, and its application. The invention involves uniformly mixing zwitterionic monomers, light absorbers, crosslinking agents, and initiators in a solvent, then immersing porous polymer foam in the above mixed solution for polymerization to obtain the highly salt-resistant zwitterionic polymer-modified photothermal material. The photothermal material of this invention has low cost, can be applied over large areas, and exhibits a high evaporation rate (up to 3.82 kg / m³) for high-salt brine. ‑2 h ‑1 Furthermore, the evaporation rate remains stable after 30 days of continuous operation, demonstrating excellent cycle performance.

Description

Technical Field

[0001] This invention belongs to the field of photothermal conversion materials technology, specifically relating to a highly salt-resistant zwitterionic polymer-modified photothermal material, its preparation method, and its application. Background Technology

[0002] High-salinity brines contain large amounts of salts and complex organic pollutants, making their treatment challenging. They typically require significant energy input, resulting in high energy consumption and costs, posing a major challenge to current wastewater treatment and recycling technologies. Solar thermal interface water evaporation technology, as an environmentally friendly clean energy technology, can effectively alleviate the global water shortage problem. Specifically, solar-driven interface water evaporation concentrates solar energy in the air. Heating at the water interface to reduce heat loss and improve thermal energy utilization is an effective way to purify water. By controlling factors such as the thermal management of photothermal materials and systems, as well as water transport, the water evaporation rate and efficiency of the photothermal system can be effectively adjusted. Therefore, solar photothermal interface water evaporation technology has become a novel, effective, and feasible solution for dealing with high-salinity brine.

[0003] In recent years, various photothermal materials, such as metal-based, carbon-based, semiconductor-based, and polymer materials, have been widely used in the construction of photothermal interfaces. However, most of them have certain limitations in application due to problems such as complex preparation methods, poor resistance to salt accumulation, high cost, or low porosity. Therefore, there is an urgent need to develop more photothermal materials with good mechanical properties, high water evaporation rate, and high stability. Summary of the Invention

[0004] The purpose of this invention is to provide a highly salt-resistant zwitterionic polymer-modified photothermal material to solve the problems of poor mechanical properties and low water evaporation rate in existing technologies. To address the above technical problems, this invention provides the following technical solution: A method for preparing a highly salt-resistant zwitterionic polymer-modified photothermal material includes the following steps: Amphoteric monomers, light absorbers, crosslinking agents, and initiators are mixed uniformly in a solvent. Then, porous polymer foam is immersed in the above mixed solution to carry out a polymerization reaction, thereby obtaining a highly salt-resistant zwitterionic polymer modified photothermal material.

[0005] In some embodiments, the zwitterionic monomer is selected from methacryloylethyl sulfobetaine (SBMA), methacryloylethyl carboxybetaine (CBMA), 2-methacryloyloxyethyl phosphoric acid choline (MPC), and trimethylamine oxide (TMAO). One or more of them.

[0006] In some embodiments, the porous polymer foam is selected from one or more of melamine foam, polyurethane foam, polyethylene foam, polypropylene foam, and phenolic resin foam, with melamine foam being preferred.

[0007] In some embodiments, the light absorber is selected from one or more of carbon black, activated carbon, graphene oxide, carbon nanotubes, Mxene, and polypyrrole; the crosslinking agent is selected from ethylene glycol dimethacrylate (EGDMA) and polyethylene glycol diacrylate (PEGDA). N , N One or more of the following: methylenebisacrylamide (MBAA), pentaerythritol tetraacrylate (PETTA), 1,3-butanediol dimethacrylate (BGDMA), 1,4-butanediol diacrylate (BDDA), 1,6-hexanediol diacrylate (HDDA), 1,6-hexanediol dimethacrylate (HDDMA), neopentyl glycol diacrylate (NPGDA), and trimethylolpropane triacrylate (TMPTA).

[0008] In some embodiments, the initiator is a photoinitiator or a thermal initiator; In some embodiments, the photoinitiator is selected from one or more of 2-hydroxy-2-methylphenylacetone, benzophenone, isopropylthioxanthanone, 2,4-diethylthioxanthanone, 4-chlorobenzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 2-hydroxy-1,2-diphenylethyl ketone, 2-ethoxy-1,2-diphenylethyl ketone, 2-butoxy-1,2-diphenylethyl ketone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, bis(2,6-difluoro-3-pyrrolephenyldicyclopentadiene), and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone. In some embodiments, the thermal initiator is selected from one or more of ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, barium peroxide, azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, 2,2'-azo(2-methylpropylamidine) dihydrochloride (AIBA), benzoyl peroxide, tert-amyl peroxide acetate, tert-amyl peroxide (2-ethylhexyl) carbonate, tert-butyl peroxide (2-ethylhexyl) carbonate, tert-amyl peroxide (3,5,5-trimethylhexanoate), tert-butyl peroxide (3,5,5-trimethylhexanoate), 1,1-di-tert-butylcyclohexane peroxide, and tert-butyl tert-valerate peroxide.

[0009] In some embodiments, the solvent is selected from one or more of H2O, dichloromethane, trichloromethane, tetrahydrofuran, acetone, ethyl acetate, methanol, ethanol, DMSO and DMF, preferably H2O.

[0010] In some embodiments, the mass ratio of the zwitterionic monomer to the light absorber is (20~80):1; the mass ratio of the zwitterionic monomer to the crosslinking agent is 1:(0.01%~1%), preferably 1:(0.01%~0.5%); and the mass ratio of the zwitterionic monomer to the initiator is 1:(0.01%~1%), preferably 1:(0.01%~0.5%).

[0011] In some embodiments, the porous polymer foam has a thickness of 5-10 mm, a cross-sectional area of ​​(1-5) cm × (1-5) cm, a porosity greater than 90%, and a pore size of 50-200 μm.

[0012] In some embodiments, the polymerization reaction includes photopolymerization and / or thermal polymerization; the thermal polymerization temperature is 50–100°C and the time is 1–10 h; the photopolymerization time is 20–90 min.

[0013] This invention also protects the highly salt-resistant zwitterionic polymer-modified photothermal material prepared by the above method.

[0014] This invention also protects the application of the above-mentioned highly salt-resistant zwitterionic polymer modified photothermal material in the desalination or purification of seawater and high-salinity brine at the solar interface.

[0015] This invention also protects the application of the above-mentioned highly salt-resistant zwitterionic polymer-modified photothermal material in salt production.

[0016] The present invention has achieved the following beneficial effects: 1) This invention utilizes the strong hydration and electrostatic repulsion of zwitterionic polymers, as well as the strong convection diffusion of macroporous structures, to coordinate and achieve high salt resistance during the water evaporation process at the solar interface, thereby achieving the ability to sustainably evaporate salt from sea / brine, and solving the problems of mechanical properties of photothermal materials and salt formation during processing under harsh conditions.

[0017] 2) Compared with traditional materials for treating high-salinity brine, the photothermal material prepared in this invention has low cost, can be applied over a large area, and exhibits a high evaporation rate for high-salinity brine, reaching 3.82 kg m³. -2 h -1 Furthermore, the evaporation rate remains stable after 30 days of continuous operation, demonstrating excellent circulation performance. It can collect salt from high-salinity brine, which is beneficial for recycling.

[0018] 3) The photothermal material prepared by this invention has excellent mechanical properties, with a fracture strength of 50 kPa and an elongation of 85%. Attached Figure Description

[0019] Figure 1 Here is a SEM image of the photothermal material obtained in Example 1; Figure 2 The tensile test results of the photothermal material obtained in Example 1 are shown below. Figure 3 This is a diagram showing the interface temperature of the photothermal material obtained in Example 1. Figure 4 The image shows the salt resistance test results of the photothermal material obtained in Example 1. Detailed implementation method: The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The endpoints and any values ​​of the ranges described in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The raw materials and reagents used in the following examples are commercially available.

[0021] Preparation Example 1: Preparation of TMAO Monomer

[0022] Add 200 mg of diethylenetriaminepentaacetic acid to 15 mL of deionized water until fully dissolved, then slowly add 10 mL of 30% H2O2 and heat to 60°C. o C. Stir the mixture thoroughly and add it to a three-necked flask filled with O2. Dissolve 3.6 g of dimethylaminopropylacrylamide in 10 ml of deionized water, then add it to the three-necked flask and stir for 6 h. After the reaction is complete, cool to room temperature and extract with dichloromethane. Place the extracted product in a freeze dryer and dry for 12 h to obtain TMAO monomer with a yield of 95%.

[0023] Example 1 A highly salt-resistant zwitterionic polymer-modified photothermal material, comprising the following steps: Prepare a 60% (w / w) TMAO monomer aqueous solution by adding TMAO monomer to deionized water; mix 10 mL of the TMAO monomer aqueous solution with 0.1 g of activated carbon, and then add 0.1 mol / L of crosslinking agent dropwise. N , N '-Methylenebisacrylamide solution (MBAA) (200 μL) and 10 g / L photoinitiator 2-hydroxy-2-methylphenylacetone solution (100 μL) were mixed evenly. A melamine foam with a thickness of 5 mm and a cross-sectional area of ​​2 cm × 2 cm (porosity 98%, pore size 100 μm) was immersed in the above mixed solution and irradiated with ultraviolet light for 30 min to allow the TMAO monomer to undergo a polymerization reaction in the melamine foam. After the reaction was completed, the melamine foam was dried to obtain a high salt-resistant zwitterionic polymer modified photothermal material.

[0024] Example 2 A highly salt-resistant zwitterionic polymer-modified photothermal material, comprising the following steps: TMAO monomer was added to deionized water to prepare a 60% (w / w) TMAO monomer aqueous solution. The TMAO monomer aqueous solution (10 mL) was mixed evenly with activated carbon (0.1 g), and then polyethylene glycol diacrylate (PEGDA) (50 μL) and 10 g / L photoinitiator 2-hydroxy-2-methylphenylacetone solution (100 μL) were added dropwise and stirred evenly. A melamine foam with a thickness of 5 mm and a cross-sectional area of ​​2 cm × 2 cm (porosity 98%, pore size 100 μm) was immersed in the above mixed solution and irradiated with ultraviolet light for 30 min to allow the TMAO monomer to polymerize in the melamine foam. After the reaction was completed, the melamine foam was dried to obtain a high salt-resistant zwitterionic polymer modified photothermal material.

[0025] Example 3 A highly salt-resistant zwitterionic polymer-modified photothermal material, comprising the following steps: Prepare a 60% (w / w) TMAO monomer aqueous solution by adding TMAO monomer to deionized water; mix 10 mL of the TMAO monomer aqueous solution with 0.1 g of activated carbon, and then add 0.1 mol / L of crosslinking agent dropwise. N , N '-Methylenebisacrylamide solution (MBAA) (200 μL) and 0.1 mol / L water-soluble thermal initiator ammonium persulfate (1 mL) were mixed thoroughly. A melamine foam (98% porosity, 100 μm pore size) with a thickness of 5 mm and a cross-sectional area of ​​2 cm × 2 cm was immersed in the above mixture and heated at 60 °C. oThe reaction was carried out in a C water bath for 4 hours to allow the TMAO monomer to polymerize within the melamine foam. After the reaction was completed, the melamine foam was dried to obtain a photothermal material modified with a highly salt-resistant zwitterionic polymer.

[0026] Example 4 A highly salt-resistant zwitterionic polymer-modified photothermal material, comprising the following steps: Prepare a 60% (w / w) TMAO monomer aqueous solution by adding TMAO monomer to deionized water; mix 10 mL of the TMAO monomer aqueous solution with 0.1 g of activated carbon, and then add 0.1 mol / L of crosslinking agent dropwise. N , N '-Methylenebisacrylamide solution (MBAA) (200 μL) and 0.1 mol / L water-soluble thermal initiator potassium persulfate (1 mL) were mixed thoroughly. A melamine foam (98% porosity, 100 μm pore size) with a thickness of 5 mm and a cross-sectional area of ​​2 cm × 2 cm was immersed in the above mixed solution and heated at 60 °C. o The reaction was carried out in a C water bath for 4 hours to allow the TMAO monomer to polymerize within the melamine foam. After the reaction was completed, the melamine foam was dried to obtain a photothermal material modified with a highly salt-resistant zwitterionic polymer.

[0027] Example 5 Based on Example 1, the TMAO monomer was replaced with methacryloyl ethyl sulfobetaine (SBMA), and other operating steps and conditions were the same as in Example 1.

[0028] Example 6 Based on Example 1, activated carbon was replaced with carbon black, and other operating steps and conditions were the same as in Example 1.

[0029] Example 7 Based on Example 1, the 5 mm melamine foam was replaced with 10 mm melamine foam, and other operating steps and conditions were the same as in Example 1.

[0030] Comparative Example 1 Based on Example 1, the 5 mm melamine foam was replaced with 2 mm melamine foam, and other operating steps and conditions were the same as in Example 1.

[0031] Comparative Example 2 Based on Example 1, the 5 mm melamine foam was replaced with 15 mm melamine foam, and other operating steps and conditions were the same as in Example 1.

[0032] Comparative Example 3 Based on Example 1, the melamine foam was replaced with nylon fabric, and other operating steps and conditions were the same as in Example 1.

[0033] Comparative Example 4 Based on Example 1, the melamine foam was replaced with suede composite fleece lamb wool fabric, and other operating steps and conditions were the same as in Example 1.

[0034] Comparative Example 5 Based on Example 1, the melamine foam was replaced with fleece fabric, and other operating steps and conditions were the same as in Example 1.

[0035] Comparative Example 6 Based on Example 1, melamine foam was replaced with polyurethane foam, and other operating steps and conditions were the same as in Example 1.

[0036] Comparative Example 7 Based on Example 1, melamine foam was replaced with polyethylene foam, and other operating steps and conditions were the same as in Example 1.

[0037] Comparative Example 8 Dissolve 10 g of sodium alginate in 500 mL of deionized water, heat and stir in a water bath at 80°C for 3 h to disperse the sodium alginate evenly in the water to obtain a sodium alginate solution; dissolve 11 g of calcium chloride powder in 500 mL of deionized water, and sonicate for 30 min to obtain a calcium chloride solution.

[0038] Melamine foam with a thickness of 5 mm and a cross-sectional area of ​​2 cm × 2 cm was completely immersed in 10 mL of sodium alginate solution for 8 h. Then, the melamine foam photothermal material was immersed in calcium chloride solution for 3 h and dried to obtain the modified photothermal material.

[0039] Comparative Example 9 Based on Example 1, the TMAO monomer was replaced with acrylamide, and other operating steps and conditions were the same as in Example 1.

[0040] Performance testing 1. SEM Testing Test method: The material to be tested was fixed on the sample stage and placed in a scanning electron microscope (SEM) under an accelerating voltage of 10 kV. By adjusting the working distance and magnification, the pore morphology, pore wall structure, and interpore connectivity of the sample were analyzed using scanning images. The SEM image of the photothermal material obtained in Example 1 is shown below. Figure 1 .

[0041] like Figure 1As shown, the photothermal material prepared in Example 1 of this invention can form uniform micropores of 1-5 μm with a porosity of over 92%. This porous structure not only provides channels for water transport but also endows the material with excellent mechanical properties. When subjected to external forces such as shearing and bending, the pores can absorb energy through deformation, and the cross-linked network formed by zwitterionic monomers can provide elastic recovery force. Furthermore, the mechanical properties of the photothermal material prepared in Example 1 were measured by… Figure 2 It can be seen that its fracture strength reaches 50 kPa and its elongation reaches 85%, therefore the photothermal material prepared by this invention has excellent mechanical properties.

[0042] 2. Solar Interface Water Evaporation Performance Test Interface temperature measurement: The interface temperature change was measured using an infrared thermal imager (FOTRIC 326) during the evaporation process of the photothermal material interface. The interface temperature of the photothermal material obtained in Example 1 is shown in [reference needed]. Figure 3 The material heats up rapidly within 1 hour, and the interface temperature stabilizes at 40~45℃, indicating that the photothermal material prepared by this invention has excellent heat-gathering ability.

[0043] Evaporation rate determination: A uniform xenon lamp (CEL-PE300L-A) was used to irradiate the materials under one solar intensity. The mass change before and after irradiation was measured in pure water and in an environment with a salt concentration of 10 wt%, thereby measuring the evaporation rate. The evaporation rate determination results of the photothermal materials prepared in Examples 1-7 and Comparative Examples 1-9 are shown in Table 1.

[0044] In addition, the photothermal material prepared in Example 1 was subjected to a long-term salt resistance test (salt concentration 10 wt%), and the results are shown in [the table below]. Figure 4 .

[0045] Table 1 Evaporation rate determination

[0046] From Table 1 and Figure 4 It can be seen that the photothermal material prepared by this invention has a high water evaporation rate, reaching 3.82 kg m³ in an environment with a salt concentration of 10 wt%. -2 h -1 This material exhibits significantly better performance than other matrix materials (nylon fabric, suede-like composite lamb wool fabric, fleece fabric, polyethylene foam, and polyurethane foam) and non-amphoionic monomers (such as acrylamide). Furthermore, its evaporation rate remains stable after 30 days of continuous operation (current technologies typically cycle for 100 hours), demonstrating excellent circulation performance. Ultimately, salt is enriched on the material surface, facilitating the collection of crystalline salts. In addition, the water evaporation rate is also related to the foam thickness; excessively low or high thickness leads to a reduced water evaporation rate.

[0047] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a photothermal material modified with a highly salt-resistant zwitterionic polymer, comprising the following steps: Amphoteric monomers, light absorbers, crosslinking agents, and initiators are mixed uniformly in a solvent. Then, porous polymer foam is immersed in the above mixed solution to carry out a polymerization reaction, thereby obtaining a highly salt-resistant zwitterionic polymer modified photothermal material.

2. The preparation method according to claim 1, characterized in that, The zwitterionic monomers are selected from methacryloylethyl sulfobetaine (SBMA), methacryloylethyl carboxybetaine (CBMA), 2-methacryloyloxyethyl phosphoric acid choline (MPC), and trimethylamine oxide (TMAO). One or more of the following: the porous polymer foam is selected from one or more of melamine foam, polyurethane foam, polyethylene foam, polypropylene foam, and phenolic resin foam.

3. The preparation method according to claim 1, characterized in that, The light absorber is selected from one or more of carbon black, activated carbon, graphene oxide, carbon nanotubes, Mxene, and polypyrrole; the crosslinking agent is selected from ethylene glycol dimethacrylate (EGDMA) and polyethylene glycol diacrylate (PEGDA). N , N One or more of the following: methylenebisacrylamide (MBAA), pentaerythritol tetraacrylate (PETTA), 1,3-butanediol dimethacrylate (BGDMA), 1,4-butanediol diacrylate (BDDA), 1,6-hexanediol diacrylate (HDDA), 1,6-hexanediol dimethacrylate (HDDMA), neopentyl glycol diacrylate (NPGDA), and trimethylolpropane triacrylate (TMPTA).

4. The preparation method according to claim 1, characterized in that, The initiator is a photoinitiator or a thermal initiator; Preferably, the photoinitiator is selected from one or more of 2-hydroxy-2-methylphenylacetone, benzophenone, isopropylthioxanthanone, 2,4-diethylthioxanthanone, 4-chlorobenzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 2-hydroxy-1,2-diphenylethyl ketone, 2-ethoxy-1,2-diphenylethyl ketone, 2-butoxy-1,2-diphenylethyl ketone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, bis(2,6-difluoro-3-pyrrolephenyldicyclopentadiene), and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone. Preferably, the thermal initiator is selected from one or more of the following: ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, barium peroxide, azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, 2,2'-azo(2-methylpropylamidine) dihydrochloride (AIBA), benzoyl peroxide, tert-amyl peroxide acetate, tert-amyl peroxide (2-ethylhexyl) carbonate, tert-butyl peroxide (2-ethylhexyl) carbonate, tert-amyl peroxide (3,5,5-trimethylhexanoate), tert-butyl peroxide (3,5,5-trimethylhexanoate), 1,1-di-tert-butylcyclohexane peroxide, and tert-butyl tert-valerate peroxide.

5. The preparation method according to claim 1, characterized in that, The solvent is selected from one or more of H2O, dichloromethane, trichloromethane, tetrahydrofuran, acetone, ethyl acetate, methanol, ethanol, DMSO and DMF, preferably H2O.

6. The preparation method according to claim 1, characterized in that, The mass ratio of the zwitterionic monomer to the light absorber is (20~80):1; the mass ratio of the zwitterionic monomer to the crosslinking agent is 1:(0.01%~1%), preferably 1:(0.01%~0.5%); the mass ratio of the zwitterionic monomer to the initiator is 1:(0.01%~1%), preferably 1:(0.01%~0.5%).

7. The preparation method according to claim 1, characterized in that, The porous polymer foam has a thickness of 5-10 mm, a cross-sectional area of ​​(1-5) cm × (1-5) cm, a porosity greater than 90%, and a pore size of 50-200 μm.

8. The preparation method according to claim 1, characterized in that, The polymerization reaction includes photopolymerization and / or thermal polymerization; the thermal polymerization temperature is 50-100℃ and the time is 1-10h; the photopolymerization time is 20-90min.

9. A highly salt-resistant zwitterionic polymer-modified photothermal material prepared by the method according to any one of claims 1 to 8.

10. The application of the high salt-resistant zwitterionic polymer modified photothermal material according to claim 9 in the desalination or purification of seawater and high-salinity brine at the solar interface.

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