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CN-121975062-A - Salt-resistant hydrogel and preparation method and application thereof

CN121975062ACN 121975062 ACN121975062 ACN 121975062ACN-121975062-A

Abstract

The invention belongs to the technical field of solar evaporator hydrogels, and particularly relates to a salt-resistant hydrogel, a preparation method and application thereof. According to the invention, sodium carboxymethyl cellulose is introduced as a first network, 3- [ N, N-dimethyl- [2- (2-methylpropan-2-enoyloxy) ethyl ] ammonium ] propane-1-sulfonate is used as a monomer, 2-hydroxyethyl methacrylate is used as a solvent, carboxylated multiwall carbon nanotubes are used as photothermal conversion materials, ammonium persulfate aqueous solution is used as an initiator, N, N' -methylene bisacrylamide is used as a cross-linking agent to form a second network, so that the hydrogel with salt tolerance and high evaporation rate is obtained, the hydrogel has high evaporation rate (the evaporation rate is 3.79kg m ‑2 h ‑1 ) and good mechanical properties (the strain is 175% and the stress is 23 kPa), and the problem that the existing evaporator hydrogel cannot be compatible with the salt tolerance, the high evaporation rate and the mechanical properties is solved.

Inventors

  • GAO ZIJIAN
  • ZHANG MENG
  • LIANG KAI
  • ZHANG FENGLI
  • LIU HONGLEI
  • KANG WENJUN
  • GUO YIHAN
  • ZHAO ZICHUN
  • MA AORAN
  • Xue Miaohui
  • WANG SHUANG
  • ZHANG YANNING

Assignees

  • 吉林化工大学

Dates

Publication Date
20260505
Application Date
20260317

Claims (8)

  1. 1. A method for preparing salt-resistant hydrogel, which is characterized by comprising the following steps: dispersing sodium carboxymethyl cellulose in water, and dissolving to form a first network of physical entanglement to obtain a first mixed solution; Adding 3- [ N, N-dimethyl- [2- (2-methylpropan-2-enoyloxy) ethyl ] ammonium ] propane-1-sulfonate and hydroxyethyl 2-methacrylate serving as monomers and carboxylated multiwall carbon nanotubes serving as photothermal conversion materials into a first mixed solution, stirring until the carboxylated multiwall carbon nanotubes are completely dissolved to obtain a second mixed solution, adding an initiator and a crosslinking agent, uniformly mixing, and then carrying out free radical polymerization reaction to enable the monomers to be polymerized and crosslinked in situ in a first network to form a second network, wherein the first network and the second network are physically crosslinked through multiple hydrogen bonds and electrostatic interactions to form a double-network hydrogel with a porous structure, and the carboxylated multiwall carbon nanotubes are dispersed in the double-network hydrogel to obtain the salt-resistant hydrogel.
  2. 2. The method for preparing salt-tolerant hydrogel according to claim 1, wherein the ratio of water to sodium carboxymethylcellulose, 3- [ N, N-dimethyl- [2- (2-methylprop-2-enoyloxy) ethyl ] ammonium ] propane-1-sulfonate, hydroxyethyl 2-methacrylate and carboxylated multi-walled carbon nanotubes in the second mixed solution is 10ml:0.08 g-0.1 g:0.5 g-0.6 g:5 ml-7 ml:0.02 g-0.04 g.
  3. 3. The method for preparing salt-resistant hydrogel according to claim 1, wherein the initiator is ammonium persulfate aqueous solution and the crosslinking agent is N, N' -methylenebisacrylamide.
  4. 4. The method for producing a salt-tolerant hydrogel according to claim 3, wherein the ratio of the amounts of sodium carboxymethyl cellulose, ammonium persulfate aqueous solution and N, N' -methylenebisacrylamide is 0.08g to 0.1g, 1mL, and 0.003g, and the concentration of the ammonium persulfate aqueous solution is ammonium persulfate aqueous solution.
  5. 5. The method for preparing a salt-resistant hydrogel according to claim 1, wherein the stirring is carried out until the temperature of complete dissolution is 50 ℃ + -5 ℃ for 20-40 min.
  6. 6. The method for preparing salt-resistant hydrogel according to claim 1, wherein the condition of the free radical polymerization reaction is that the temperature is 80 ℃ plus or minus 5 ℃ and the time is 3-5 h.
  7. 7. A salt-resistant hydrogel prepared by the method for preparing a salt-resistant hydrogel according to any one of claims 1 to 6.
  8. 8. Use of a salt-tolerant hydrogel as a hydrogel evaporator, characterized in that the salt-tolerant hydrogel is according to claim 7.

Description

Salt-resistant hydrogel and preparation method and application thereof Technical Field The invention belongs to the technical field of solar seawater desalination and solar evaporator hydrogel, and particularly relates to salt-resistant hydrogel and a preparation method and application thereof. Background Along with the continuous increase of the demand of fresh water resources, the solar seawater desalination technology becomes one of the important ways for solving the crisis of fresh water resources due to the characteristics of renewable energy sources and environmental friendliness. In many solar seawater desalination technologies, an interface solar evaporator realizes local heating and efficient evaporation by concentrating a photo-thermal conversion material on a gas-liquid interface, so that the solar energy utilization efficiency is remarkably improved, and the solar energy desalination technology has been receiving attention in recent years. Hydrogel is used as a high polymer material with a three-dimensional network structure, and has great application potential in the field of solar evaporators due to excellent water absorption and water retention capacity, good biocompatibility and adjustable physicochemical properties. Compared with the traditional solar evaporator, the hydrogel evaporator has the advantages of strong water absorption capacity, light weight and portability, can solve the problems of high cost and difficult transportation of the traditional solar evaporator, and becomes one of candidate materials of the solar evaporator. Therefore, the preparation of hydrogels with good salt tolerance and high evaporation rates is of great interest in solar evaporator applications. Currently, hydrogel-based solar evaporators are prepared to improve evaporation performance and salt tolerance mainly by two strategies, namely, reduction of evaporation enthalpy and construction of a porous structure. The strategy for reducing the evaporation enthalpy is mainly to introduce hydrophilic groups into a hydrogel network or regulate polymer-water interaction, so that the energy required by evaporation of water molecules is reduced, the evaporation enthalpy is reduced, and the evaporation efficiency is improved. The strategy for constructing the porous structure mainly adopts the means of freeze drying, phase separation, a template method or a foaming method and the like to construct rich porous channels in the hydrogel so as to enhance the water molecule transmission capacity and the photo-thermal conversion efficiency. Although the preparation strategy can improve the evaporation performance of the hydrogel to a certain extent, the prepared hydrogel still has the defects of low evaporation rate and poor salt tolerance, so that the hydrogel is greatly limited in application. In addition, the introduction of the porous structure often comes at the expense of mechanical properties, resulting in a decrease in mechanical strength, which in turn affects the structural stability and long-term reliability of the hydrogels. Disclosure of Invention The invention provides a salt-resistant hydrogel and a preparation method and application thereof, and aims to solve the problems that the evaporation rate is low, the salt resistance difference and the mechanical property are insufficient, and the structural stability and the long-term reliability of the hydrogel are further affected in the prior art. According to the invention, by constructing a double-network structure of a first network of sodium carboxymethyl cellulose and a second network of copolymerization of zwitterionic/hydroxyl monomers, physical crosslinking is formed by utilizing multiple hydrogen bonds and electrostatic interactions among networks, and the photo-thermal conversion effect of carboxylated multiwall carbon nanotubes is cooperated, so that the problems of low evaporation efficiency, easy salt crystallization blocking and low mechanical strength of the traditional hydrogel evaporator are solved, and the effects of high evaporation rate, excellent salt tolerance, good mechanical property and synchronous purification of organic pollutants are realized. In order to achieve the above object, the technical scheme of the present invention is as follows. In one aspect, the invention provides a method for preparing a salt-tolerant hydrogel, comprising the steps of: Dispersing sodium carboxymethyl cellulose in water to form a first network of physical entanglement, dissolving to obtain a first mixed solution, adding 3- [ N, N-dimethyl- [2- (2-methylpropan-2-enoyloxy) ethyl ] ammonium ] propane-1-sulfonate and hydroxyethyl 2-methacrylate serving as monomers into the first mixed solution, stirring until the sodium carboxymethyl cellulose is completely dissolved to obtain a second mixed solution, adding an initiator and a cross-linking agent, uniformly mixing, and performing free radical polymerization reaction to enable the monomers to be polymerized and