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CN-117547976-B - Humidity responsive CO2Composite membrane preparation method

CN117547976BCN 117547976 BCN117547976 BCN 117547976BCN-117547976-B

Abstract

The invention relates to a preparation method of a humidity response CO 2 composite membrane, which comprises the following steps of adding anhydrous piperazine into carboxymethyl chitosan solution, dissolving and mixing to obtain CMCs-PiP mixed solution, coating the CMCs-PiP mixed solution on a polyether sulfone supporting layer in a multi-layer manner, drying to obtain the CMCs-PiP/PES composite membrane, and mixing the CMCs-PiP/PES composite membrane with the following components Dissolving the particles in a mixed solvent of n-propanol and n-butanol, and refluxing and stirring to obtain Solution to be processed The solution is coated on CMCs-PiP/PES composite film in multiple layers, and is dried to obtain And (3) a composite membrane. The CO 2 separation composite membrane prepared by the invention is beneficial to improving the compatibility between the supporting layer and the selective layer by introducing carboxymethyl chitosan as the intermediate layer of the composite membrane, and effectively reduces the resistance of the intermediate layer to CO 2 transmission by the assistance of water, thereby being beneficial to the practical application of CO 2 separation and filling the blank of the intermediate layer research in the prior art.

Inventors

  • CAO JINGGUO
  • LU JIAWEI

Assignees

  • 天津科技大学

Dates

Publication Date
20260505
Application Date
20231206

Claims (8)

  1. 1. The preparation method of the humidity response CO 2 composite film is characterized by comprising the following steps of: S1, adding anhydrous piperazine into a carboxymethyl chitosan solution, dissolving and mixing to obtain a CMCs-PiP mixed solution, wherein the anhydrous piperazine is added as a small molecule auxiliary agent to perform entanglement with a polymer chain of carboxymethyl chitosan, and the anhydrous piperazine separates out cations in water to perform self-assembly with an anionic polymer of carboxymethyl chitosan so as to enhance power transmitted by CO 2 ; S2, coating the CMCs-PiP mixed solution on a polyether sulfone supporting layer in a multi-layer manner, and drying to obtain the CMCs-PiP/PES composite membrane; s3, dissolving the Pebax 3533 particles in a mixed solvent of n-propanol and n-butanol, and refluxing and stirring to obtain a Pebax 3533 solution; s4, coating the Pebax 3533 solution on the CMCs-PiP/PES composite membrane in a plurality of layers, drying to obtain the Pebax 3533/CMCs-PiP/PES composite membrane, Before the polyethersulfone supporting layer is coated, the polyethersulfone supporting layer is pretreated, the pretreatment comprises repeatedly cleaning the polyethersulfone supporting layer, soaking the polyethersulfone supporting layer in a sodium dodecyl sulfate aqueous solution, soaking the polyethersulfone supporting layer in n-hexane again to fill pores of a film, slowing down the penetration of the solution into the pores, and wiping the surface and fixing the surface on the surface of a glass plate.
  2. 2. The method for preparing the humidity-responsive CO 2 composite membrane according to claim 1, wherein in the step S1, carboxymethyl chitosan is dissolved in water to obtain 1wt% of carboxymethyl chitosan solution, and the anhydrous piperazine is added in the stirring process, wherein the relative mass of the anhydrous piperazine is 20% of that of carboxymethyl chitosan, so as to obtain the CMCs-PiP mixed solution.
  3. 3. The method for preparing a humidity responsive CO 2 composite membrane according to claim 1, wherein in step S2, two layers are coated on the polyethersulfone supporting layer using the CMCs-PiP mixed solution.
  4. 4. The method for preparing the humidity-responsive CO 2 composite membrane according to claim 3, wherein in the step S2, the CMCs-PiP mixed solution is cast on a polyether sulfone supporting layer, the coating is carried out by adopting a micrometer coater, the above operation is repeated for 1 time after drying, and the CMCs-PiP/PES composite membrane is obtained after drying.
  5. 5. The method for preparing a humidity-responsive CO 2 composite membrane according to claim 2, wherein in step S3, the Pebax 3533 particles are dissolved in a mixed solvent of n-propanol and n-butanol in a volume ratio of 3:1, and the mixture is refluxed and stirred at 80 ℃ for 2 hours, to obtain 0.5wt% of the Pebax 3533 solution.
  6. 6. The method for preparing a humidity-responsive CO 2 composite membrane according to claim 5, wherein the CMCs-PiP mixed solution or Pebax 3533 solution is filtered by using a sample injector and a 0.45 μm filter membrane filter to remove undissolved small particles, and then bubbles in the solution are removed by a vacuum decompression method.
  7. 7. The method for preparing the humidity-responsive CO 2 composite membrane according to claim 1, wherein in the step S4, the Pebax 3533 solution is cast on the CMCs-PiP/PES composite membrane, a micrometer coater is adopted for coating, the above operation is repeated for 1 time after drying, and the Pebax 3533/CMCs-PiP/PES composite membrane is obtained after drying.
  8. 8. The method for preparing a humidity-responsive CO 2 composite membrane according to claim 1, wherein the polyether sulfone supporting layer is soaked in 0.5wt% aqueous solution of sodium dodecyl sulfate for 24hours, and then soaked in n-hexane for 2 hours again.

Description

Preparation method of humidity-responsive CO 2 composite membrane Technical Field The invention relates to the technical field of membrane separation, in particular to a preparation method of a humidity-responsive CO 2 composite membrane. Background The growing prominence of global warming issues has made reducing greenhouse gas emissions, particularly carbon dioxide (CO 2) emissions, an urgent need. Among them, flue gas generated in the combustion power generation process has become a main source of CO 2 emissions, and to cope with this challenge, separation and capture of CO 2 from flue gas has become critical. At present, CO 2 is separated mainly by technologies such as pressure swing adsorption, amine washing, low-temperature distillation, membrane separation and the like. Among these technologies, membrane separation technology is widely practiced in academia and industry with its efficiency, low cost and design flexibility. The existing gas separation membranes can be largely classified into dense polymer membranes and ultra-thin composite membranes (UTFC). While dense membranes exhibit good gas selectivity, their gas permeability is relatively poor. In contrast, UTFC successfully reduced the permeation resistance of gases due to its ultra-thin membrane layer structure. Typically UTFC consists of a multilayer structure including a support layer (providing mechanical strength), an intermediate layer (improving the compatibility between the support layer and the polymer selection layer) and a selection layer (mainly contributing to the gas separation). Although the research on the selective layer is rich at present, the research on the intermediate layer is relatively less, so that the intermediate layer cannot further improve the compatibility between the intermediate layer and the selective layer, further the stability and long-term use reliability of the membrane cannot be fully ensured, and the actual application of CO 2 separation is influenced due to the high resistance of the intermediate layer to CO 2 transmission at present, so that the intermediate layer is still further improved. Disclosure of Invention The invention aims to solve the technical problem of overcoming the defects in the prior art and providing a preparation method of a CO 2 composite membrane with humidity response. The invention is realized by the following technical scheme: A preparation method of a humidity-responsive CO 2 composite membrane comprises the following steps: s1, adding anhydrous piperazine into a carboxymethyl chitosan solution, and dissolving and mixing to obtain a CMCs-PiP mixed solution; S2, coating the CMCs-PiP mixed solution on a polyether sulfone supporting layer in a multi-layer manner, and drying to obtain the CMCs-PiP/PES composite membrane; S3, will The 3533 particles are dissolved in a mixed solvent of n-propanol and n-butanol, and are obtained after reflux and stirring3533 Solution; s4, the step of Coating 3533 solution on the CMCs-PiP/PES composite film in multiple layers, and drying to obtain3533/CMCs-PiP/PES complex film. According to the technical scheme, in the step S1, preferably, carboxymethyl chitosan is dissolved in water to obtain a carboxymethyl chitosan solution with the weight percentage of 1%, and the anhydrous piperazine with the relative mass of 20% of that of the carboxymethyl chitosan is added in the stirring process to obtain a CMCs-PiP mixed solution. According to the above technical solution, preferably, in step S2, 2 layers are coated on the polyethersulfone supporting layer using the CMCs-PiP mixed solution. According to the technical scheme, in the step S2, preferably, the CMCs-PiP mixed solution is cast on a polyether sulfone supporting layer, and is coated by a micrometer coater, and the above operation is repeated for 1 time after drying, and the CMCs-PiP/PES composite membrane is obtained after drying. According to the above technical solution, preferably, in step S3, the following is performed3533 Particles were dissolved in a 3:1 volume ratio of n-propanol to n-butanol mixed solvent and stirred at 80 ℃ under reflux for 2 hours to give 0.5wt% of the above3533 Solution. According to the above technical scheme, preferably, the CMCs-PiP mixed solution orThe 3533 solution was filtered using a sample injector and 0.45 μm filter membrane filter to remove undissolved small particles, and then the bubbles in the solution were removed by vacuum depressurization. According to the above technical solution, preferably, in step S4, the following is performedCasting 3533 solution on the CMCs-PiP/PES composite membrane, coating with micrometer coater, oven drying, repeating the above steps for 1 time, and drying to obtain3533/CMCs-PiP/PES complex film. According to the technical scheme, the polyether sulfone supporting layer is preferably subjected to pretreatment, wherein the pretreatment comprises the steps of repeatedly cleaning the polyether sulfone supporting layer, soaking the po