CN-121974447-A - TEMPO-CNT composite film based on layer-by-layer assembly, preparation method and application

Abstract

The invention discloses a TEMPO-CNT composite film based on layer-by-layer assembly, a preparation method and application thereof, and belongs to the technical field of preparation of electrochemical wastewater treatment materials. The composite membrane adopts a layer-by-layer assembly process, and a carbon-based conductive adsorption layer and a TEMPO catalytic function layer are sequentially constructed on a basal layer to form an ordered layered structure. The structure fully maintains the high specific surface area and conductivity of the carbon material, and enables TEMPO active sites to be uniformly exposed, thereby realizing the efficient synergy of pollutant adsorption and electrocatalytic degradation. The composite membrane prepared by the invention can be suitable for various direct current and alternating current (pulse) electrochemical systems, can efficiently remove trace organic pollutants in wastewater with low energy consumption by applying corresponding voltages, and has the advantages of flexible operation, wide application scene, good environmental compatibility and the like.

Inventors

• YAN WENXIN
• QIU ZHEN
• YU BING
• FENG HUAJUN
• SHEN JINCHAO
• WANG MIN
• JIN MIN
• Bian Xinyan

Assignees

• 浙江农林大学

Dates

Publication Date

20260505

Application Date

20260327

Claims (10)

1. 1. A preparation method of a TEMPO-CNT composite film based on layer-by-layer assembly is characterized by comprising the specific steps of uniformly loading conductive adsorption layer dispersion liquid containing a carbon-based material on the surface of a substrate layer to obtain an intermediate product, uniformly loading catalytic function layer dispersion liquid containing a TEMPO material on the surface of the intermediate product, and carrying out heat treatment to obtain the TEMPO-CNT composite film assembled layer by layer.
2. 2. The preparation method of the TEMPO-CNT composite film based on layer-by-layer assembly according to claim 1 is characterized in that carbon-based materials in the conductive adsorption layer dispersion liquid are carbon nanotubes or graphene, and the solvent is ethanol.
3. 3. The preparation method of the TEMPO-CNT composite film based on layer-by-layer assembly according to claim 2, wherein the concentration of carbon nanotubes in the conductive adsorption layer dispersion is 5-20 mg/mL, and the mass ratio of TEMPO material to carbon nanotubes in the catalytic functional layer dispersion is (1-4): 4-1.
4. 4. The preparation method of the TEMPO-CNT composite film based on layer-by-layer assembly according to claim 1 is characterized in that TEMPO material in the catalytic functional layer dispersion is prepared as follows: S1, fully dissolving a TEMPO polymer precursor material in an organic solvent subjected to nitrogen blowing and oxygen removal, and then adding an azodiisobutyronitrile solution into the solution under an anaerobic condition for polymerization reaction; S2, dissolving the first polymer in tetrahydrofuran solution, cooling, adding an oxidant, and uniformly mixing to perform oxidation reaction to obtain a second polymer; And S3, dropwise adding the second polymer into a sodium hydroxide solution, removing excessive tetrahydrofuran, and drying the product to obtain the partially oxidized TEMPO material.
5. 5. The preparation method of the TEMPO-CNT composite film based on layer-by-layer assembly according to claim 4, wherein the TEMPO polymer precursor material adopts 2, 6-tetramethylpiperidine-4-methacrylate, the organic solvent adopts N, N-dimethylformamide or N, N-dimethylacetamide, and the oxidant adopts m-chloroperoxybenzoic acid.
6. 6. The preparation method of the TEMPO-CNT composite film based on layer-by-layer assembly according to claim 1, wherein the substrate layer is a polyethylene terephthalate film or a polyvinylidene fluoride film, and the substrate layer is a polyvinylidene fluoride film filter film with a pore diameter of 0.1-1 μm, a diameter of 0.5-5 cm and a thickness of 0.2-3 mm.
7. 7. The preparation method of the TEMPO-CNT composite film based on layer-by-layer assembly according to claim 1, wherein the temperature of the heat treatment process is controlled to be 60-80 ℃ and the time is 20-24 hours.
8. 8. A TEMPO-CNT composite film produced according to the production method of any one of claims 1 to 7.
9. 9. The application of the TEMPO-CNT composite film in water treatment is characterized in that the TEMPO-CNT composite film is used as a working electrode to be placed in a three-electrode reaction system, waste water to be treated containing trace organic pollutants is added into an electrolytic reaction tank, so that the waste water to be treated flows through the TEMPO-CNT composite film, constant direct current potential is applied to the working electrode, the trace organic pollutants in the waste water to be treated are subjected to catalytic oxidative degradation after adsorption and enrichment on the surface of the composite film, electrolyte sodium sulfate or sodium chloride is further contained in the waste water to be treated, and the trace organic pollutants are one or more of sulfamethoxazole, carbamazepine, phenol or methylene blue.
10. 10. The application of the TEMPO-CNT composite film in water treatment is characterized in that two TEMPO-CNT composite films are respectively used as an anode and a cathode to be placed in an electrolytic reaction system, waste water to be treated containing trace organic pollutants is added into an electrolytic reaction tank so that the waste water to be treated flows through the TEMPO-CNT composite film, and periodically-transformed asymmetric voltage is applied to the anode and the cathode so that the trace organic pollutants in the waste water to be treated are subjected to catalytic oxidative degradation after adsorption and enrichment on the surface of the composite film, wherein the pulse period is 1-120 s, and the positive-negative voltage ratio is (1-7): 7~1; The waste water to be treated also contains electrolyte sodium sulfate or sodium chloride, and the trace organic pollutants are one or more of sulfamethoxazole, carbamazepine, phenol or methylene blue.

Description

TEMPO-CNT composite film based on layer-by-layer assembly, preparation method and application Technical Field The invention belongs to the technical field of preparation of electrochemical wastewater treatment materials, and particularly relates to a TEMPO-CNT composite film based on layer-by-layer assembly, a preparation method and application. Background The sustainable development of membrane water treatment technology is always developed around the core demands of efficient purification, stable operation, energy consumption optimization, multi-scene adaptation and the like. In practical application, the technology needs to accurately target and remove trace organic pollutants in a water body, such as micro/nanogram endocrine disruptors and other refractory substances, and needs to keep the removal rate at least 85% under the condition of complex matrixes such as tap water, municipal secondary effluent and the like, and meanwhile, the technology has strong anti-interference capability. In addition, the membrane material also provides low pollution and long service life, and the membrane material is expected to be regenerated in situ in an electrochemical green mode, so that the regeneration efficiency is more than or equal to 80 percent, and the energy consumption for removing the unit pollutant is less than or equal to 0.5 kWh/mol. In the aspect of application scenes, the membrane technology is required to be adapted to multiple scenes such as drinking water purification, industrial wastewater treatment, municipal wastewater recycling and the like, and the miniature convenient application and large-scale industrial treatment are considered, so that the cyclic utilization of the power-assisted water resource and the water quality safety guarantee are realized with the low-consumption environment-friendly characteristic. In this context, electrochemical processing techniques are receiving widespread attention for their clean, efficient nature. However, most of the existing electrode materials are designed for cathode or anode reactions under the direct current condition, and stable and efficient treatment performance is difficult to maintain in the alternating current environment with periodically switched polarities. The TEMPO material and carbon-based material (such as carbon nano tube, graphene and the like) composite membrane electrode combines excellent redox reversibility of the TEMPO material and high conductivity of the carbon-based material, and has good application prospect in the field of electrochemical water treatment, in particular to an alternating current mode. However, the practical properties of the composite are limited by the deficiencies of the existing manufacturing processes. At present, common preparation methods, such as a spin coating method, a blending impregnation method and the like, are often difficult to realize uniform and stable compounding of TEMPO and a carbon-based material in an electrode. In the preparation method provided by the invention patent with the publication number of CN119034507B, because of intrinsic characteristics of materials such as surface electrical repulsion of TEMPO and carbon nano tubes in a precursor liquid (TEMPO/CNT mixed liquid), the prepared film is easy to fall off or material agglomeration occurs in the catalytic application process. In summary, the conventional TEMPO-carbon-based composite electrode still faces challenges in terms of preparation process, structural stability, broad spectrum contaminant removal universality, and the like. Therefore, there is a need to provide an electrode material having high electrocatalytic activity, excellent membrane stability and good operational adaptability, and a method for preparing the same. Disclosure of Invention The invention aims to solve the defects in the prior art and provides a TEMPO-CNT composite film based on layer-by-layer assembly, a preparation method and application. The specific technical scheme adopted by the invention is as follows: According to the first aspect, the invention provides a preparation method of a TEMPO-CNT composite film based on layer-by-layer assembly, which comprises the specific steps of uniformly loading a conductive adsorption layer dispersion liquid containing a carbon-based material on the surface of a substrate layer to obtain an intermediate product, uniformly loading a catalytic functional layer dispersion liquid containing a TEMPO material on the surface of the intermediate product, and performing heat treatment to obtain the TEMPO-CNT composite film assembled layer by layer. Preferably, the carbon-based material in the conductive adsorption layer dispersion liquid adopts carbon nanotubes or graphene, and the solvent adopts ethanol. Further, the concentration of the carbon nano tube in the conductive adsorption layer dispersion liquid is 5-20 mg/mL, and the mass ratio of TEMPO material to the carbon nano tube in the catalytic function layer dispersion liq